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  • 1.
    Alshamari, Muhammed
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Geijer, Mats
    Center for Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden; Lund University, Lund, Sweden.
    Norrman, Eva
    Örebro University Hospital.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Low-dose computed tomography of the lumbar spine: a phantom study on imaging parameters and image quality2014In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 55, no 7, p. 824-832Article in journal (Refereed)
    Abstract [en]

    Background: Lumbar spine radiography has limited diagnostic value but low radiation dose compared with computed tomography (CT). The average effective radiation dose from lumbar spine radiography is about 1.1 mSv. Low-dose lumbar spine CT may be an alternative to increase the diagnostic value at low radiation dose, around 1 mSv.

    Purpose: To determine the optimal settings for low-dose lumbar spine CT simultaneously aiming for the highest diagnostic image quality possible.

    Material and Methods: An ovine lower thoracic and lumbar spine phantom, with all soft tissues around the vertebrae preserved except the skin, was placed in a 20 L plastic container filled with water. The phantom was scanned repeatedly with various technical settings; different tube potential, reference mAs, and with different convolution filters. Five radiologists evaluated the image quality according to a modification of the European guidelines for multislice computed tomography (MSCT) quality criteria for lumbar spine CT 2004. In a visual comparison the different scans were also ranked subjectively according to perceived image quality. Image noise and contrast were measured.

    Results: A tube potential of 120 kV with reference mAs 30 and medium or medium smooth convolution filter gave the best image quality at a sub-millisievert dose level, i.e. with an effective dose comparable to that from lumbar spine radiography.

    Conclusion: Low-dose lumbar spine CT thus opens a possibility to substitute lumbar spine radiography with CT without obvious increase in radiation dose.

  • 2.
    Alshamari, Muhammed
    et al.
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Geijer, Mats
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden; Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden.
    Norrman, Eva
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Lidén, Mats
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Krauss, Wolfgang
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Jendeberg, Johan
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Magnuson, Anders
    Örebro University Hospital.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine2017In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 58, no 6, p. 702-709Article in journal (Refereed)
    Abstract [en]

    Background: Iterative reconstruction (IR) is a recent reconstruction algorithm for computed tomography (CT) that can be used instead of the standard algorithm, filtered back projection (FBP), to reduce radiation dose and/or improve image quality.

    Purpose: To evaluate and compare the image quality of low-dose CT of the lumbar spine reconstructed with IR to conventional FBP, without further reduction of radiation dose.

    Material and Methods: Low-dose CT on 55 patients was performed on a Siemens scanner using 120 kV tube voltage, 30 reference mAs, and automatic dose modulation. From raw CT data, lumbar spine CT images were reconstructed with a medium filter (B41f) using FBP and four levels of IR (levels 2-5). Five reviewers scored all images on seven image quality criteria according to the European guidelines on quality criteria for CT, using a five-grade scale. A side-by-side comparison was also performed.

    Results: There was significant improvement in image quality for IR (levels 2-4) compared to FBP. According to visual grading regression, odds ratios of all criteria with 95% confidence intervals for IR2, IR3, IR4, and IR5 were: 1.59 (1.39-1.83), 1.74 (1.51-1.99), 1.68 (1.46-1.93), and 1.08 (0.94-1.23), respectively. In the side-by-side comparison of all reconstructions, images with IR (levels 2-4) received the highest scores. The mean overall CTDIvol was 1.70 mGy (SD 0.46; range, 1.01-3.83 mGy). Image noise decreased in a linear fashion with increased strength of IR.

    Conclusion: Iterative reconstruction at levels 2, 3, and 4 improves image quality of low-dose CT of the lumbar spine compared to FPB.

  • 3.
    Alshamari, Muhammed
    et al.
    Örebro University, School of Medical Sciences. Department of Radiology.
    Geijer, Mats
    Department of Radiology, School of Medical Sciences, Örebro University, Örebro, Sweden; Department of Medical Imaging and Physiology, Skåne University Hospital, Lund; Lund University, Lund, Sweden.
    Norrman, Eva
    Department of Medical Physics, School of Medical Sciences, Örebro University, Örebro, Sweden.
    Lidén, Mats
    Örebro University, School of Health Sciences.
    Krauss, Wolfgang
    Örebro University, School of Health Sciences.
    Jendeberg, Johan
    Örebro University, School of Health Sciences.
    Magnuson, Anders
    Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health Sciences.
    Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spineManuscript (preprint) (Other academic)
  • 4.
    Alshamari, Muhammed
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Geijer, Mats
    Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden.
    Norrman, Eva
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Medical Physics,, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Lidén, Mats
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Krauss, Wolfgang
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Wilamowski, Franciszek
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Low dose CT of the lumbar spine compared with radiography: a study on image quality with implications for clinical practice2016In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 57, no 5, p. 602-611Article in journal (Refereed)
    Abstract [en]

    Background: Lumbar spine radiography is often performed instead of CT for radiation dose concerns.

    Purpose: To compare image quality and diagnostic information from low dose lumbar spine CT at an effective dose of about 1 mSv with lumbar spine radiography.

    Material and Methods: Fifty-one patients were examined by both methods. Five reviewers scored all examinations on eight image quality criteria using a five-graded scale and also assessed three common pathologic changes.

    Results: Low dose CT scored better than radiography on the following: sharp reproduction of disc profile and vertebral end-plates (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.3-2.5), intervertebral foramina and pedicles (OR, 4.3; 95% CI, 3.1-5.9), intervertebral joints (OR, 139; 95% CI, 59-326), spinous and transverse processes (OR, 7.0; 95% CI, 4.3-11.2), sacro-iliac joints (OR, 4.2; 95% CI, 3.2-5.7), reproduction of the adjacent soft tissues (OR, 2.9; 95% CI, 2.1-4.0), and absence of any obscuring superimposed gastrointestinal gas and contents (OR, 188; 95% CI, 66-539). Radiography scored better on sharp reproduction of cortical and trabecular bone (OR, 0.3; 95% CI, 0.2-0.4). The reviewers visualized disk degeneration, spondylosis/diffuse idiopathic skeletal hyperostosis (DISH) and intervertebral joint osteoarthritis more clearly and were more certain with low dose CT. Mean time to review low dose CT was 204 s (95% CI, 194-214 s.), radiography 152 s (95% CI, 146-158 s.). The effective dose for low dose CT was 1.0-1.1 mSv, for radiography 0.7 mSv.

    Conclusion: Low dose lumbar spine CT at about 1 mSv has superior image quality to lumbar spine radiography with more anatomical and diagnostic information.

  • 5.
    Alshamari, Muhammed
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Norrman, Eva
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Geijer, Mats
    Department of Medical Imaging and Physiology, Lund University, Lund, Sweden; Skåne University Hospital, Lund, Sweden.
    Jansson, Kjell
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Surgery, Örebro University Hospital, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review2016In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 26, no 6, p. 1766-1774Article in journal (Refereed)
    Abstract [en]

    Objectives: Abdominal radiography is frequently used in acute abdominal non-traumatic pain despite the availability of more advanced diagnostic modalities. This study evaluates the diagnostic accuracy of low-dose CT compared with abdominal radiography, at similar radiation dose levels.

    Methods: Fifty-eight patients were imaged with both methods and were reviewed independently by three radiologists. The reference standard was obtained from the diagnosis in medical records. Sensitivity and specificity were calculated. A systematic review was performed after a literature search, finding a total of six relevant studies including the present.

    Results: Overall sensitivity with 95 % CI for CT was 75 % (66-83 %) and 46 % (37-56 %) for radiography. Specificity was 87 % (77-94 %) for both methods. In the systematic review the overall sensitivity for CT varied between 75 and 96 % with specificity from 83 to 95 % while the overall sensitivity for abdominal radiography varied between 30 and 77 % with specificity 75 to 88 %.

    Conclusions: Based on the current study and available evidence, low-dose CT has higher diagnostic accuracy than abdominal radiography and it should, where logistically possible, replace abdominal radiography in the workup of adult patients with acute non-traumatic abdominal pain.

    Key points: • Low-dose CT has a higher diagnostic accuracy than radiography. • A systematic review shows that CT has better diagnostic accuracy than radiography. • Radiography has no place in the workup of acute non-traumatic abdominal pain.

  • 6.
    Andersson, Karin M.
    et al.
    Department of Medical Physics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Norrman, Eva
    Department of Medical Physics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Krauss, Wolfgang
    Örebro University, School of Medical Sciences. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Cao, Yang
    Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden; Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Jendeberg, Johan
    Örebro University, School of Medical Sciences. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Geijer, Mats
    Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; Department of Clinical Sciences, Lund University, Lund, Sweden.
    Lidén, Mats
    Örebro University, School of Medical Sciences. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Thunberg, Per
    Örebro University, School of Medical Sciences. Department of Medical Physics, Örebro University Hospital, Örebro, Sweden .
    Visual grading evaluation of commercially available metal artefact reduction techniques in hip prosthesis computed tomography2016In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 89, no 1063, article id 20150993Article in journal (Refereed)
    Abstract [en]

    Objectives: To evaluate metal artefact reduction (MAR) techniques from four computed tomography (CT) vendors in hip prosthesis imaging.

    Methods: Bilateral hip prosthesis phantom images, obtained by using MAR algorithms for single energy CT data or dual energy CT (DECT) data and by monoenergetic reconstructions of DECT data, were visually graded by five radiologists using ten image quality criteria. Comparisons between the MAR images and a reference image were performed for each scanner separately. Ordinal probit regression analysis was used.

    Results: The MAR algorithms in general improved the image quality based on the majority of the criteria (up to between 8/10 and 10/10) with a statistically improvement in overall image quality (P<0.001). However, degradation of image quality, such as new artefacts, was seen in some cases. A few monoenergetic reconstruction series improved the image quality (P<0.004) for one of the DECT scanners, but it was only improved for some of the criteria (up to 5/10). Monoenergetic reconstructions resulted in worse image quality for the majority of the criteria (up to 7/10) for the other DECT scanner.

    Conclusions: The MAR algorithms improved the image quality of the hip prosthesis CT images. However, since additional artefacts and degradation of image quality were seen in some cases, all algorithms should be carefully evaluated for every clinical situation. Monoenergetic reconstructions were in general concluded to be insufficient for reducing metal artifacts. Advances in knowledge: Qualitative evaluation of the usefulness of several MAR techniques from different vendors in CT imaging of hip prosthesis.

  • 7.
    Bäck, Anna
    et al.
    Örebro University, School of Health Sciences. Department of Radiology.
    Savvopoulos, C.
    Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Funk, Eva
    Örebro University, School of Health Sciences. Division of Medical Diagnostics.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology.
    Diuretic decision seven minutes post Tc-99m-MAG3 administration in a renography2018In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 45, no Suppl. 1, p. S765-S765, article id E-TPW52Article in journal (Other academic)
    Abstract [en]

    Aim: The F+10 method in supine position, which has been implemented at our Nuclear Medicine department since 2015, involves a 30- minute long dynamic acquisition. The diuretic is only administered when necessary and decision is taken by the radiographers in a semi-automated fashion without consulting a physician, by calculating the remaining activity in the kidneys seven minutes post 99mTc-MAG3 injection and comparing the value with an arbitrary threshold of 75 %. If needed, the diuretic is injected three minutes later. The aim of this study was to correlate our method with the established previously used F+20 protocol in adults. Is the currently used threshold of 75% of activity left in any kidney at seven minutes the optimal cut-off value for diuretic administration?

    Material and Methods: This is an ongoing retrospective study which include 320 F+20 examinations of adult patients performed during 2013-2015. They were all re-evaluated according to the currently used F+10 method, categorized as requiring diuretic or not and correlated to the original F+20 examination. A ROC-curve was drawn to delineate the best cut-off value for remaining renal activity. Sensitivity, specificity and accuracy were calculated.

    Results: Preliminary results indicate that the F+10 re-evaluations with the currently used cut-off value of 75% did not correlate with the original F+20 examinations. In 80% (255 examinations) of the F+10 re-evaluations diuretic would have been considered necessary while only 52% (167 examinations) received diuretics in the original F+20 renographies (sensitivity 1.0, specificity 0.42). However, all the patients who required furosemide in the original F+20 renographies would have received diuretic if they had been imaged with the F+10 protocol. Furthermore, examination time is considerably reduced. After an evaluation of the ROC-curve the optimal cut-off value was 94% (sensitivity 0.92, specificity 0.84, accuracy 0.88). However, by implementing this value, 13 patients (4%) would have been falsely categorized as not requiring diuretic.

    Conclusions: The 99mTc-MAG3 renography with the F+10 protocol in supine position is a feasible and acceptable method in clinical practice.

  • 8.
    Geijer, Håkan
    et al.
    Örebro University, School of Medical Sciences. Ctr Assessment Med Technol, Örebro University Hospital, Örebro, Sweden.
    Breimer, Lars H.
    Ctr Assessment Med Technol, Örebro University Hospital, Örebro, Sweden.
    Somatostatin receptor PET/CT in neuroendocrine tumours: update on systematic review and meta-analysis2013In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 40, no 11, p. 1770-1780Article, review/survey (Refereed)
    Abstract [en]

    Purpose Neuroendocrine tumours (NET) are uncommon and may be localized in many different places in the body. Traditional imaging has mainly been performed with CT and somatostatin receptor scintigraphy (SRS). Recently, it has become possible to use somatostatin receptor PET/CT (SMSR PET) instead, which might improve diagnostic quality. To evaluate the diagnostic quality of SMSR PET we performed a meta-analysis as an update of a previous study published in 2012. A literature search was performed searching MEDLINE, Embase and five other databases with a combination of the expressions "PET", "positron emission tomography", "neuroendocrine" and "NET". The search was updated to 31 December 2012. Studies were selected which evaluated the sensitivity and specificity of SMSR PET for NET in the thorax or abdomen with a study size of at least eight patients. The methodological quality of the included studies was evaluated with QUADAS-2. Eight studies fulfilled the inclusion criteria and were selected for final analysis, and 14 articles from a previous meta-analysis were added for a total of 22 articles. A total of 2,105 patients were included in the studies, an increase from 567 in the previous meta-analysis. The pooled sensitivity was 93 % (95 % CI 91 - 94 %) and specificity 96 % (95 % CI 95 - 98 %). The area under the summary ROC curve was 0.98 (95 % CI 0.95 - 1.0). In the previous meta-analysis the pooled sensitivity was 93 % (95 % CI 91 - 95 %) and specificity 91 % (95 % CI 82 - 97 %). SMSR PET has good diagnostic performance for evaluation of NET in the thorax and abdomen, better than SRS which has been the previous standard method. This meta-analysis gives further support for switching to SMSR PET.

  • 9.
    Geijer, Håkan
    et al.
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Geijer, Mats
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden; Department of Radiology, Skåne University Hospital, Lund, Sweden; Lund University, Lund, Sweden.
    Added value of double reading in diagnostic radiology, a systematic review2018In: Insight into Imaging, ISSN 1869-4101, E-ISSN 1869-4101, Vol. 9, no 3, p. 287-301Article, review/survey (Refereed)
    Abstract [en]

    OBJECTIVES: Double reading in diagnostic radiology can find discrepancies in the original report, but a systematic program of double reading is resource consuming. There are conflicting opinions on the value of double reading. The purpose of the current study was to perform a systematic review on the value of double reading.

    METHODS: A systematic review was performed to find studies calculating the rate of misses and overcalls with the aim of establishing the added value of double reading by human observers.

    RESULTS: The literature search resulted in 1610 hits. After abstract and full-text reading, 46 articles were selected for analysis. The rate of discrepancy varied from 0.4 to 22% depending on study setting. Double reading by a sub-specialist, in general, led to high rates of changed reports.

    CONCLUSIONS: The systematic review found rather low discrepancy rates. The benefit of double reading must be balanced by the considerable number of working hours a systematic double-reading scheme requires. A more profitable scheme might be to use systematic double reading for selected, high-risk examination types. A second conclusion is that there seems to be a value of sub-specialisation for increased report quality. A consequent implementation of this would have far-reaching organisational effects.

    KEY POINTS: • In double reading, two or more radiologists read the same images. • A systematic literature review was performed. • The discrepancy rates varied from 0.4 to 22% in various studies. • Double reading by sub-specialists found high discrepancy rates.

  • 10.
    Geijer, Håkan
    et al.
    Örebro University, School of Medical Sciences.
    Geijer, Mats
    Örebro University, School of Medical Sciences. Örebro University Hospital.
    Double reading in diagnostic radiology: a systematic review2019Conference paper (Other academic)
  • 11. Geijer, Håkan
    et al.
    Norrman, Eva
    Örebro University, Department of Natural Sciences.
    Persliden, Jan
    Optimizing the tube potential for lumbar spine radiography with a flat-pane digital detector2009In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 82, no 973, p. 62-68Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to find the optimal settings for lumbar spine radiography with a flat-panel detector. A CDRAD contrast-detail phantom was imaged at various tube potentials, system speeds and filtration settings. Factorial experiments yielded a range of optimized exposure settings, which were submitted to visual grading analysis with images of an Alderson phantom. The first optimized settings involved a system speed increase from 400 to 800. For anteroposterior projection, the optimal tube potential was reduced from the default of 77 kV to 60 kV to give the best image quality without increasing the effective dose, or to 66 kV to give the lowest dose without reducing image quality. For lateral projection, the tube potential was similarly reduced from the default of 90 kV to 70 kV or 77 W. Visual grading analysis confirmed the results, with significantly better image quality when optimizing for image quality. The study thus shows that the tube potential can be reduced as long as the system speed is increased simultaneously. This leads to a lower effective dose and/or increased image quality depending on the settings chosen. The factorial experiments provided a powerful way to evaluate several parameters concomitantly.

  • 12.
    Geijer, Håkan
    et al.
    Örebro University, School of Medical Sciences. Centre for Assessment of Medical Technology in Örebro, Region Örebro County, Örebro, Sweden; Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Udumyan, Ruzan
    Örebro University, School of Medical Sciences. Örebro University Hospital, Örebro, Sweden.
    Lohse, Georg
    Centre for Assessment of Medical Technology in Örebro, Region Örebro County, Örebro, Sweden; Örebro Rehab Center, Örebro, Sweden.
    Nilsagård, Ylva
    Örebro University, School of Health Sciences. Centre for Assessment of Medical Technology in Örebro, Region Örebro County, Örebro, Sweden; Department of Medicine, Örebro University Hospital, Örebro, Sweden.
    Temperature measurements with a temporal scanner: systematic review and meta-analysis2016In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 6, no 3, article id e009509Article in journal (Refereed)
    Abstract [en]

    Objectives: Systematic review and meta-analysis on the diagnostic accuracy of temporal artery thermometers (TAT).

    Design: Systematic review and meta-analysis. The index test consisted of temperature measurement with TAT. The reference test consisted of an estimation of core temperature.

    Participants: Clinical patients as well as healthy participants, with or without fever.

    Interventions: Literature search in PubMed, Embase, Cinahl and Web of Science. Three reviewers selected articles for full-text reading after which a further selection was made. Risk of bias was assessed with QUADAS-2. Pooled difference and limits of agreement (LoA) were estimated with an inverse variance weighted approach. Subgroup and sensitivity analyses were performed. Sensitivity and specificity were estimated using hierarchical models. Quality of evidence was assessed according to the GRADE system.

    Primary and secondary outcome measures: The primary outcome was measurement accuracy expressed as mean difference ±95% LoA. A secondary outcome was sensitivity and specificity to detect fever. If tympanic thermometers were assessed in the same population as TAT, these results were recorded as well.

    Results: 37 articles comprising 5026 participants were selected. Pooled difference was -0.19°C (95% LoA -1.16 to 0.77°C), with moderate quality of evidence. Pooled sensitivity was 0.72 (95% CI 0.61 to 0.81) with a specificity of 0.94 (95% CI 0.87 to 0.97). The subgroup analysis revealed a trend towards underestimation of the temperature for febrile patients. There was a large heterogeneity among included studies with wide LoA which reduced the quality of evidence.

    Conclusions: TAT is not sufficiently accurate to replace one of the reference methods such as rectal, bladder or more invasive temperature measurement methods. The results are, however, similar to those with tympanic thermometers, both in our meta-analysis and when compared with others. Thus, it seems that TAT could replace tympanic thermometers with the caveat that both methods are inaccurate.

    Trial registration number: CRD42014008832.

  • 13.
    Geijer, Mats
    et al.
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden; Department of Clinical Sciences, Lund University, Lund, Sweden.
    Gunnlaugsson, Eirikur
    Department of Medical Imaging and Physiology, Lund University, Lund, Sweden; Skåne University Hospital, Lund, Sweden.
    Götestrand, Simon
    Department of Medical Imaging and Physiology, Lund University, Lund, Sweden; Skåne University Hospital, Lund, Sweden.
    Weber, Lars
    Department of Radiation Physics, Skåne University Hospital, Lund, Sweden.
    Geijer, Håkan
    Örebro University, School of Health Sciences. Department of Radiology.
    Tomosynthesis of the thoracic spine: added value in diagnosing vertebral fractures in the elderly2017In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 27, no 2, p. 491-497Article in journal (Refereed)
    Abstract [en]

    Objectives: Thoracic spine radiography becomes more difficult with age. Tomosynthesis is a low-dose tomographic extension of radiography which may facilitate thoracic spine evaluation. This study assessed the added value of tomosynthesis in imaging of the thoracic spine in the elderly.

    Methods: Four observers compared the image quality of 50 consecutive thoracic spine radiography and tomosynthesis data sets from 48 patients (median age 67 years, range 55-92 years) on a number of image quality criteria. Observer variation was determined by free-marginal multirater kappa. The conversion factor and effective dose were determined from the dose-area product values.

    Results: For all observers significantly more vertebrae were seen with tomosynthesis than with radiography (mean 12.4/9.3, P < 0.001) as well as significantly more fractures (mean 0.9/0.7, P = 0.017). The image quality score for tomosynthesis was significantly higher than for radiography, for all evaluated structures. Tomosynthesis took longer to evaluate than radiography. Despite this, all observers scored a clear preference for tomosynthesis. Observer agreement was substantial (mean κ = 0.73, range 0.51-0.94). The calibration or conversion factor was 0.11 mSv/(Gy cm(2)) for the combined examination. The resulting effective dose was 0.87 mSv.

    Conclusion: Tomosynthesis can increase the detection rate of thoracic vertebral fractures in the elderly, at low added radiation dose.

    KEY POINTS:• Tomosynthesis helps evaluate the thoracic spine in the elderly. • Observer agreement for thoracic spine tomosynthesis was substantial (mean κ = 0.73). • Significantly more vertebrae and significantly more fractures were seen with tomosynthesis. • Tomosynthesis took longer to evaluate than radiography. • There was a clear preference among all observers for tomosynthesis over radiography.

  • 14.
    Gustafsson, Agnetha
    et al.
    Department of Medical Physics, IMH, Linköping University, Linköping, Sweden; Radiation Physics UHL, County council of Östergötland, Linköping, Sweden.
    Karlsson, Henrik
    Department of Radiation Physics, Kalmar County Hospital, Kalmar, Sweden.
    Nilsson, Kerstin A.
    Department of Clinical Physiology UHL, County Council of Östergötland, Linköping, Sweden.
    Geijer, Håkan
    Örebro University Hospital. Department of Radiology.
    Olsson, Anna
    Department of Medical Physics, IMH, Linköping University, Linköping, Sweden; Radiation Physics UHL, County council of Östergötland, Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
    A visual grading study for different administered activity levels in bone scintigraphy2015In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 35, no 3, p. 231-236Article in journal (Refereed)
    Abstract [en]

    Introduction: The aim of the study is to assess the administered activity levels versus visual-based image quality using visual grading regression (VGR) including an assessment of the newly stated image criteria for whole-body bone scintigraphy.

    Materials and methods: A total of 90 patients was included and grouped in three levels of administered activity: 400, 500 and 600 MBq. Six clinical image criteria regarding image quality was formulated by experienced nuclear medicine physicians. Visual grading was performed in all images, where three physicians rated the fulfilment of the image criteria on a four-step ordinal scale. The results were analysed using VGR. A count analysis was also made where the total number of counts in both views was registered.

    Results: The administered activity of 600 MBq gives significantly better image quality than 400 MBq in five of six criteria (P<005). Comparing the administered activity of 600 MBq to 500 MBq, four criteria of six show significantly better image quality (P<005). The administered activity of 500 MBq gives no significantly better image quality than 400 Mbq (P<005). The count analysis shows that none of the three levels of administrated activity fulfil the recommendations by the EANM.

    Conclusion: There was a significant improvement in perceived image quality using an activity level of 600 MBq compared to lower activity levels in whole-body bone scintigraphy for the gamma camera equipment end set-up used in this study. This type of visual-based grading study seems to be a valuable tool and easy to implement in the clinical environment.

  • 15. Jansson, Margareta
    et al.
    Geijer, Håkan
    Örebro University, Department of Clinical Medicine.
    Persliden, Jan
    Örebro University, Department of Clinical Medicine.
    Andersson, Torbjörn
    Örebro University, Department of Clinical Medicine.
    Reducing dose in urography while maintaining image quality - a comparison of storage phosphor plates and a flat-panel detector2006In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 16, no 1, p. 221-226Article in journal (Refereed)
    Abstract [en]

    The introduction of new flat-panel detector technology often forces us to accept too high dose levels as proposed by the manufacturers. We need a tool to compare the image quality of a new system with the accepted standard. The aim of this study was to obtain a comparable image quality for two systems-storage phosphor plates and a flat-panel system using intravenous urography (IVU) as a clinical model. The image quality figure was calculated using a contrast-detail phantom (CDRAD) for the two evaluated systems. This allowed us to set a dose for the flat-panel system that gave equivalent image quality to the storage phosphor plates. This reduced detector dose was used in an evaluation of clinical images to find out if the dose reduction from the phantom study indeed resulted in images of equal clinical image quality. The image quality was assessed using image criteria of the European guidelines for IVU with visual grading analysis. Equivalent image quality in image pairs was achieved at 30% of the dose. The CDRAD contrast-detail phantom makes it possible to find dose levels that give equal image quality using different imaging systems.

  • 16.
    Jendeberg, Johan
    et al.
    Örebro University, School of Medical Sciences.
    Cierzniak, B.
    Alshamari, Muhammed
    Örebro University, School of Medical Sciences. Örebro University Hospital.
    Geijer, Håkan
    Örebro University, School of Medical Sciences.
    Lidén, Mats
    Örebro University, School of Medical Sciences.
    Prognosis of spontaneous ureteral stone passage: as revealed by CT2016Conference paper (Refereed)
  • 17.
    Jendeberg, Johan
    et al.
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Alshamari, Muhammed
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Cierzniak, Bartosz
    Department of Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Lidén, Mats
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage2017In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 27, no 11, p. 4775-4785Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To determine how to most accurately predict the chance of spontaneous passage of a ureteral stone using information in the diagnostic non-enhanced computed tomography (NECT) and to create predictive models with smaller stone size intervals than previously possible.

    METHODS: Retrospectively 392 consecutive patients with ureteric stone on NECT were included. Three radiologists independently measured the stone size. Stone location, side, hydronephrosis, CRP, medical expulsion therapy (MET) and all follow-up radiology until stone expulsion or 26 weeks were recorded. Logistic regressions were performed with spontaneous stone passage in 4 weeks and 20 weeks as the dependent variable.

    RESULTS: The spontaneous passage rate in 20 weeks was 312 out of 392 stones, 98% in 0-2 mm, 98% in 3 mm, 81% in 4 mm, 65% in 5 mm, 33% in 6 mm and 9% in ≥6.5 mm wide stones. The stone size and location predicted spontaneous ureteric stone passage. The side and the grade of hydronephrosis only predicted stone passage in specific subgroups.

    CONCLUSION: Spontaneous passage of a ureteral stone can be predicted with high accuracy with the information available in the NECT. We present a prediction method based on stone size and location.

    KEY POINTS: • Non-enhanced computed tomography can predict the outcome of ureteral stones. • Stone size and location are the most important predictors of spontaneous passage. • Prediction models based on stone width or length and stone location are introduced. • The observed passage rates for stone size in mm-intervals are reported. • Clinicians can make better decisions about treatment.

  • 18.
    Jendeberg, Johan
    et al.
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Alshamari, Muhammed
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Lidén, Mats
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Prediction of spontaneous ureteral stone passage: Automated 3D-measurements perform equal to radiologists, and linear measurements equal to volumetric2018In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 28, no 6, p. 2474-2483Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To compare the ability of different size estimates to predict spontaneous passage of ureteral stones using a 3D-segmentation and to investigate the impact of manual measurement variability on the prediction of stone passage.

    METHODS: We retrospectively included 391 consecutive patients with ureteral stones on non-contrast-enhanced CT (NECT). Three-dimensional segmentation size estimates were compared to the mean of three radiologists' measurements. Receiver-operating characteristic (ROC) analysis was performed for the prediction of spontaneous passage for each estimate. The difference in predicted passage probability between the manual estimates in upper and lower stones was compared.

    RESULTS: The area under the ROC curve (AUC) for the measurements ranged from 0.88 to 0.90. Between the automated 3D algorithm and the manual measurements the 95% limits of agreement were 0.2 ± 1.4 mm for the width. The manual bone window measurements resulted in a > 20 percentage point (ppt) difference between the readers in the predicted passage probability in 44% of the upper and 6% of the lower ureteral stones.

    CONCLUSIONS: All automated 3D algorithm size estimates independently predicted the spontaneous stone passage with similar high accuracy as the mean of three readers' manual linear measurements. Manual size estimation of upper stones showed large inter-reader variations for spontaneous passage prediction.

    KEY POINTS:• An automated 3D technique predicts spontaneous stone passage with high accuracy.• Linear, areal and volumetric measurements performed similarly in predicting stone passage.• Reader variability has a large impact on the predicted prognosis for stone passage.

  • 19.
    Johansson, Benny L.
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Souza, Domingos S. R.
    Bodin, Lennart
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Filbey, Derek
    Loesch, Andrzej
    Geijer, Håkan
    Department of Thoracic Radiology, Örebro University Hospital, Örebro, Sweden.
    Bojo, Leif
    Slower progression of atherosclerosis in vein grafts harvested with 'no touch' technique compared with conventional harvesting technique in coronary artery bypass grafting: an angiographic and intravascular ultrasound study2010In: European Journal of Cardio-Thoracic Surgery, ISSN 1010-7940, E-ISSN 1873-734X, Vol. 38, no 4, p. 414-419Article in journal (Refereed)
    Abstract [en]

    Objectives: In a long-term randomised coronary artery bypass grafting (CABG) study, the patency rate using a new 'no touch' (NT) vein-graft preparation technique was superior to the conventional (C) technique. This cineangiographic and intravascular ultrasound (IVUS) substudy examined possible mechanisms.

    Methods: A total of 45 patients (118 grafts) in the NT group and 46 patients (112 grafts) in the C group had patent grafts at short-term follow-up after 18 months. Thirty-seven patients (91 grafts) in the NT group and 37 patients (77 grafts) in the C group had patent grafts at long-term follow-up after 8 5 years, and were evaluated on a scale from 0 (normal) to 2 (significant stenosis) by cineangiogram. IVUS was performed in 15 NT grafts and 14 C grafts in the short-term follow-up, and 27 NT grafts and 26 C grafts in the long-term follow-up, in grafts considered normal by the cineangiogram. The grafts were evaluated with respect to lumen volume, intimal thickness, incidence of plaque and plaque components.

    Results: In the short-term follow-up, the cineangiogram showed more normal grafts (89.0% in the NT group compared with 75.0% in the C group), and the number of grafts with stenosis was 11.0% in the NT group compared with 25.0% in the C group (p = 0.006). IVUS showed less mean intimal thickness (0.43 (0.07) mm vs 0.52 (0.08) mm; p = 0.03), less grafts with considerable intimal hyperplasia (>= 0.9 mm; 20% vs 78.6%; p = 0.011) and fewer patients with considerable hyperplasia (>= 0.9 mm; 25% vs 100%; p = 0.007). In the long-term follow-up, the cineangiogram showed more normal grafts, with 91.2% in the NT group compared with 83.1% in the C group; there were fewer grafts with significant stenosis, with 7.7% in the NT group compared with 15 6% in the C group (p = 0.14). IVUS showed fewer grafts containing multiple plaques (14.8% vs 50%; p = 0.008), less advanced plaque with lipid (11.8% vs 63.9%; p = 0.0004) and less maximal plaque thickness (1.04 (0.23) mm vs 1.32 (0.25) mm; p = 0.02) in the NT group compared with the C group.

    Conclusion: The superior long-term patency rate using the NT vein-graft technique at CABG could be explained by a significantly slower progression of atherosclerosis. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  • 20.
    Kähäri, Anders
    et al.
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Thunberg, Per
    Department of Biomedical Engineering, Örebro University Hospital, Örebro, Sweden.
    Emilsson, Kent
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Clinical Physiology, Karlskoga Hospital, Karlskoga, Sweden.
    Geijer, Håkan
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Andersson, Torbjörn
    Wandt, Birger
    Assessment of left ventricular function from M-mode measurement of circumflex artery motion recorded by coronary angiography.2003In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 37, no 5, p. 259-265Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To evaluate the usefulness of M-mode measurement of circumflex artery motion (CAM) for assessment of left ventricular (LV) function.

    DESIGN: Seventy-two patients referred for coronary angiography and LV angiography were included. Ejection fraction (EF) was calculated from LV angiography and systolic and diastolic parameters of CAM were measured by M-mode from coronary angiography. Twenty-three patients, examined by echocardiography of mitral annulus motion (MAM) within 24 h before the angiographic examination, formed a subgroup for comparison between angiographic M-mode of CAM and echocardiographic M-mode of MAM.

    RESULTS: In addition to previous reported CAM amplitude and longitudinal fractional shortening (FSL) the maximal systolic velocity of CAM can be reliably recorded by M-mode. The diastolic indices, atrial contribution to the total amplitude and maximal early and late diastolic velocities, are also well monitored by M-mode of CAM in comparison with echocardiographic MAM.

    CONCLUSION: LV systolic and diastolic function can be assessed by M-mode of CAM.

  • 21.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Andersson, Torbjörn
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Broxvall, Mathias
    Örebro University, School of Science and Technology.
    Thunberg, Per
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Urinary stone size estimation: a new segmentation algorithm-based CT method2012In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 22, no 4, p. 731-737Article in journal (Refereed)
    Abstract [en]

    The size estimation in CT images of an obstructing ureteral calculus is important for the clinical management of a patient presenting with renal colic. The objective of the present study was to develop a reader independent urinary calculus segmentation algorithm using well-known digital image processing steps and to validate the method against size estimations by several readers. Fifty clinical CT examinations demonstrating urinary calculi were included. Each calculus was measured independently by 11 readers. The mean value of their size estimations was used as validation data for each calculus. The segmentation algorithm consisted of interpolated zoom, binary thresholding and morphological operations. Ten examinations were used for algorithm optimisation and 40 for validation. Based on the optimisation results three segmentation method candidates were identified. Between the primary segmentation algorithm using cubic spline interpolation and the mean estimation by 11 readers, the bias was 0.0 mm, the standard deviation of the difference 0.26 mm and the Bland-Altman limits of agreement 0.0 +/- 0.5 mm. The validation showed good agreement between the suggested algorithm and the mean estimation by a large number of readers. The limit of agreement was narrower than the inter-reader limit of agreement previously reported for the same data. The size of kidney stones is usually estimated manually by the radiologist. An algorithm for computer-aided size estimation is introduced. The variability between readers can be reduced. A reduced variability can give better information for treatment decisions.

  • 22.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences.
    Andersson, Torbjörn
    Örebro University, School of Health and Medical Sciences.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences.
    Alternative user interface devices for improved navigation of CT datasets2011In: Journal of digital imaging, ISSN 0897-1889, E-ISSN 1618-727X, Vol. 24, no 1, p. 126-134Article in journal (Refereed)
    Abstract [en]

    The workflow in radiology departments has changed dramatically with the transition to digital PACS, especially with the shift from tile mode to stack mode display of volumetric images. With the increasing number of images in routinely captured datasets, the standard user interface devices (UIDs) become inadequate. One basic approach to improve the navigation of the stack mode datasets is to take advantage of alternative UIDs developed for other domains, such as the computer game industry. We evaluated three UIDs both in clinical practice and in a task-based experiment. After using the devices in the daily image interpretation work, the readers reported that both of the tested alternative UIDs were better in terms of ergonomics compared to the standard mouse and that both alternatives were more efficient when reviewing large CT datasets. In the task-based experiment, one of the tested devices was faster than the standard mouse, while the other alternative was not significantly faster. One of the tested alternative devices showed a larger number of traversed images during the task. The results indicate that alternative user interface devices can improve the navigation of stack mode datasets and that radiologists should consider the potential benefits of alternatives to the standard mouse.

  • 23.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences.
    Andersson, Torbjörn
    Örebro University, School of Medicine, Örebro University, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences.
    Making renal stones change size: impact of CT image post processing and reader variability2011In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 21, no 10, p. 2218-2225Article in journal (Refereed)
    Abstract [en]

    Objectives The objectives of this study were to quantify the impact of image post-processing parameters on the apparent renal stone size, and to quantify the intra- and inter-reader variability in renal stone size estimation. Methods Fifty CT datasets including a renal or ureteral stone were included retrospectively during a prospective inclusion period. Each of the CT datasets was post-processed in different ways regarding slice thickness, slice increment and window setting. In the first part of the study a single reader repeated size estimations for the renal stones using different post-processing parameters. In the intra-reader variability experiment one reader reported size estimations for the same images with a one-week interval. The inter-reader variability data were obtained from 11 readers reporting size estimations for the same renal stones. Results The apparent stone size differed according to image post-processing parameters with the largest mean differences seen with regard to the window settings experiment (1.5 mm, p < 0.001) and slice thickness (0.8 mm, p < 0.001). Changes in parameters introduced a bias and a pseudo-random variability. The inter-reader variability was considerably larger than the intra-reader variability. Conclusion Our results indicate a need for the standardisation of making measurements on CT images.

  • 24.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Andersson, Torbjörn
    Örebro University, School of Medicine, Örebro University, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Urinary stone size estimation: Can we reduce the reader variations?Manuscript (preprint) (Other academic)
  • 25.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Thunberg, Per
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Kliniskt forskningscentrum (KFC), Univeritetssjukhuset, Örebro, Sverige.
    Broxvall, Mathias
    Örebro University, School of Science and Technology.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Two- and three-dimensional CT measurements of urinary calculi length and width: a comparative studyManuscript (preprint) (Other academic)
    Abstract [en]

    The standard imaging procedure for a patient presenting with renal colic is unenhanced CT. The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on 2d-reformats. In the present study we developed and validated a calculus oriented 3dmethod for measurements of length and width of urinary calculi and compared those with corresponding 2d measurements in axial and coronal reformats.

    Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3d-symmetric segmentation algorithm was validated against reader size estimations. The calculus-oriented size from the segmentation was then compared to the size in axial and coronal reformats.

    Results: The validation showed 0.1±0.7 mm agreement against reference measure. There was a 0.4 mm median bias for 3d-estimated calculus length compared to 2d (p<0.001), but no significant bias for 3d-width compared to 2d.

    Conclusion: The size of the urinary calculus becomes underestimated if its orientation is not aligned to the axial or coronal image plane. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.

  • 26.
    Lidén, Mats
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
    Thunberg, Per
    Örebro University Hospital. Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. School of Health and Medical Sciences, Örebro University, Örebro, Sweden; Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Broxvall, Mathias
    Modeling and Simulation Research Center, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Two- and three-dimensional CT measurements of urinary calculi length and width: a comparative study2015In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 56, no 4, p. 487-492Article in journal (Refereed)
    Abstract [en]

    Background: The standard imaging procedure for a patient presenting with renal colic is unenhanced computed tomography (CT). The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on two-dimensional (2D) reformats.

    Purpose: To develop and validate a calculus oriented three-dimensional (3D) method for measuring the length and width of urinary calculi and to compare the calculus oriented measurements of the length and width with corresponding 2D measurements obtained in axial and coronal reformats.

    Material and Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3D symmetric segmentation algorithm was validated against reader size estimations. The calculus oriented size from the segmentation was then compared to the estimated size in axial and coronal 2D reformats.

    Results: The validation showed 0.1 +/- 0.7mm agreement against reference measure. There was a 0.4mm median bias for 3D estimated calculus length compared to 2D (P < 0.001), but no significant bias for 3D width compared to 2D.

    Conclusion: The length of a calculus in axial and coronal reformats becomes underestimated compared to 3D if its orientation is not aligned to the image planes. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.

  • 27.
    Lundin, Margareta
    et al.
    Department of Radiology, Örebro University Hospital, Örebro University, Örebro, Sweden.
    Liden, Mats
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro University, Örebro, Sweden.
    Magnuson, Anders
    Clinical Epidemiology and Biostatistic Unit, Örebro University Hospital, Örebro, Sweden.
    Mohammed, Ahmed Abdulilah
    Department of Radiology, Linköping University Hospital, Linköping, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro University, Örebro, Sweden.
    Andersson, Torbjörn
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro University, Örebro, Sweden.
    Persson, Anders
    Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
    Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study2012In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 53, no 6, p. 689-694Article in journal (Refereed)
    Abstract [en]

    Background: Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce. a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation.

    Purpose: To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model.

    Material and Methods: Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard.

    Results: The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition.

    Conclusion: Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system.

  • 28.
    Piippo-Huotari, Oili
    et al.
    Örebro University, School of Health Sciences. Department of Radiology.
    Norrman, Eva
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Medical Physics.
    Anderzen-Carlsson, Agneta
    Örebro University, School of Health Sciences. Örebro University Hospital. University Health Care Research Center.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology.
    New patient-controlled abdominal compression method in radiography: radiation dose and image quality2018In: Acta radiologica open, ISSN 2058-4601, Vol. 7, no 5, p. 1-8, article id 2058460118772863Article in journal (Refereed)
    Abstract [en]

    Background: The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position.

    Purpose: To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography.

    Material and Methods: An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images.

    Results: There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality.

    Conclusion: Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

  • 29.
    Samano, Ninos
    et al.
    Örebro University, School of Health Sciences. Department of Cardiothoracic and Vascular Surgery.
    Bodin, Lennart
    Karolinska Institute, Stockholm, Sweden.
    Karlsson, Jan
    University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health Sciences. Department of Radiology.
    Arbeus, Mikael
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Souza, Domingos
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Graft patency is a predictor of health-related quality of life after coronary artery bypass surgeryManuscript (preprint) (Other academic)
  • 30.
    Samano, Ninos
    et al.
    Örebro University Hospital. Örebro University, School of Medical Sciences. Department of Cardiothoracic and Vascular Surgery, Örebro University Hospital, Örebro, Sweden.
    Bodin, Lennart
    Örebro University, Örebro University School of Business. Intervention and Implementation Research, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Karlsson, Jan
    Örebro University, School of Medical Sciences. Örebro University Hospital. University Health Care Research Center, Region Örebro County, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Arbeus, Mikael
    Department of Cardiothoracic and Vascular Surgery, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Souza, Domingos
    Örebro University Hospital. Department of Cardiothoracic and Vascular Surgery, Örebro University Hospital, Örebro, Sweden.
    Graft patency is associated with higher health-related quality of life after coronary artery bypass surgery2016In: Interactive Cardiovascular and Thoracic Surgery, ISSN 1569-9293, E-ISSN 1569-9285, Vol. 24, no 3, p. 388-394Article in journal (Refereed)
    Abstract [en]

    Objectives: The objective of this study was to investigate whether graft patency was associated with higher health-related quality of life in coronary artery bypass grafting patients and to compare this study with the general Swedish population.

    Methods: Patients were included from 3 randomized trials and 1 prospective cohort trial. The generic health-related quality of life instrument, EQ-5D (VAS and index) was used. Graft patency was assessed with computed tomography angiography. Patients were divided into 2 groups according to the number of occluded distal anastomosis: Group I with no to 1 occlusion (n = 209) and Group II with 2 to 4 occlusions (n = 24).

    Results: Two hundred and thirty-three patients underwent computed tomography angiography at a mean of 7.5 (1-18) years post-operatively. The mean difference in EQ-VAS and EQ-5D index between Groups II and I after model adjustment was -19.8 (95% CI -25.3 to -14.3; P < 0.001) and -0.13 (95% CI -0.19 to -0.08; P < 0.001), respectively. The EQ-5D index for the study population was similar compared with the Swedish population, 0.851 and 0.832, respectively, with an effect-size of 0.112 (trivial). The EQ-5D index of the study population was higher compared with the ischemic heart disease group in the Swedish population, 0.851 vs 0.60, with an effect-size of 0.999 (large).

    Conclusion: Graft patency was associated with higher health-related quality of life in coronary artery bypass patients. This patient group reported similar function and wellbeing compared to the general Swedish population and better health status than those in the same disease group in the general population.

    Clinical registration number: Clinicaltrials.gov: NCT02547194 and the Research and Development registry in Sweden: 167861.

  • 31.
    Samano, Ninos
    et al.
    Örebro University, School of Health Sciences. Department of Cardiothoracic and Vascular Surgery.
    Geijer, Håkan
    Örebro University, School of Health Sciences. Department of Radiology.
    Bodin, Lennart
    Karolinska Institute, Stockholm, Sweden.
    Arbeus, Mikael
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Mannion, J. D.
    Department of Surgery, Bayhealth Medical Center, Dover, DE, USA.
    Dashwood, M.
    Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, UK.
    Souza, Domingos
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    The no-touch saphenous vein graft in high-risk coronary bypass patients is a reliable conduit to substitute the left internal thoracic arteryManuscript (preprint) (Other academic)
  • 32.
    Samano, Ninos
    et al.
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Cardiothoracic and Vascular Surgery.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Bodin, Lennart
    Örebro University, Örebro University School of Business. Intervention and Implementation Research, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Arbeus, Mikael
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Mannion, John D.
    Department of Surgery, Bayhealth Medical Center, Dover DE, USA.
    Dashwood, Michael
    Surgical and Interventional Sciences, Royal Free Hospital Campus, University College Medical School, London, United Kingdom.
    Souza, Domingos
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    The no-touch saphenous vein graft in elderly coronary bypass patients with multiple comorbidities is a promising conduit to substitute the left internal thoracic artery2017In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 154, no 2, p. 457-466.e3Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: We investigated the patency rates of no-touch saphenous vein grafts anastomosed to the left anterior descending artery compared with the left internal thoracic artery. Further, we compared the patency of no-touch vein grafts to the left anterior descending artery with the patency of no-touch vein grafts to other coronary arteries.

    METHODS: Of 2635 consecutive patients undergoing coronary artery bypass grafting between 2003 and 2008, 168 (6.3%) were given at least a saphenous vein graft to the left anterior descending artery to avoid harvesting complications in high-risk patients or in response to a left internal thoracic artery injury. A total of 97 patients were consecutively included after informed consent. A clinical examination and computed tomography angiography were performed on 91 patients at a mean of 6 (4-9) years.

    RESULTS: The mean age of patients was 75.6 ± 8.5 years. Postoperatively, 88.7% of patients (86/97) were free of angina. The 91 examined patients had 163 grafts with 286 distal anastomoses. Crude patency, according to distal anastomoses, was 94.4% (270/286). The patency of single versus sequential no-touch vein grafts to the left anterior descending artery was 98% (50/51) versus 92.5% (37/40). The total patency rate was 95.6% (87/91), similar to the reported patency rate for the left internal thoracic artery. The no-touch grafts to the left anterior descending artery versus other coronaries had a patency of 95.6% (87/91) versus 93.8% (183/195), a high similarity confirmed by an equivalence analysis.

    CONCLUSIONS: In elderly coronary bypass patients with multiple comorbidities, a no-touch saphenous vein graft is a promising substitute for the left internal thoracic artery.

  • 33.
    Samano, Ninos
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Cardiothoracic and Vascular Surgery, Örebro University Hospital, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Lidén, Mats
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Fremes, Stephen
    Division of Cardiac Surgery, Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto ON, Canada.
    Bodin, Lennart
    Intervention and Implementation Research, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Souza, Domingos S. R.
    Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    The no-touch saphenous vein for coronary artery bypass grafting maintains a patency, after 16 years, comparable to the left internal thoracic artery: a randomized trial2015In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 150, no 4, p. 880-888Article in journal (Refereed)
    Abstract [en]

    Objectives: This study investigates whether the no-touch (NT) vein graft, at a mean time of 16 years, maintains a significantly higher patency rate than conventional (C) vein grafts and still has patency comparable to that of the left internal thoracic artery (LITA).

    Methods: A total of 156 patients accepted for coronary artery bypass grafting were randomly allocated to 1 of 3 groups. In the C group, the saphenous vein (SV) was stripped and distended. In the intermediate group, the SV was stripped but not distended. In the NT group, the SV was neither stripped nor distended, but rather harvested with a fat pedicle. This study is an angiographic follow-up of the C and NT groups, at a mean time of 16 years postoperatively.

    Results: Fifty-four patients were included (C group = 27; NT group = 27). In all, 72 and 75 vein grafts were completed in groups C and NT, respectively. Crude SV graft patency was 64% in the C group versus 83% in the NT group (P = .03), which was similar to the patency of the LITA (88%). The harvesting technique had a major impact on the patency with a hazard ratio for occlusion of 1.83 for the C group (P = .04).

    Conclusions: Harvesting the SV with the NT technique conferred, at a mean time of 16 years, a significantly higher patency than the conventional technique that was still comparable to that of the LITA.

  • 34.
    Savilampi, Johanna
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital.
    Ahlstrand, Rebecca
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital.
    Wattwil, Magnus
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital, Örebro, Sweden.
    Aspiration during monitored anesthesia care reply2015In: Anesthesiology, ISSN 0003-3022, E-ISSN 1528-1175, Vol. 122, no 2, p. 472-472Article in journal (Refereed)
  • 35.
    Savilampi, Johanna
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Anaesthesiology and Intensive Care, Örebro University Hospital, Örebro, Sweden.
    Ahlstrand, Rebecca
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Anaesthesiology and Intensive Care, Örebro University Hospital, Örebro, Sweden; Centre for Health Care Sciences, Örebro University Hospital, Örebro, Sweden.
    Magnuson, Anders
    Clinical Epidemiology and Biostatistic Unit, Örebro University Hospital, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Wattwil, Magnus
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Anaesthesiology and Intensive Care, Örebro University Hospital, Örebro, Sweden.
    Aspiration Induced by Remifentanil: A Double-blind, Randomized, Crossover Study in Healthy Volunteers2014In: Anesthesiology, ISSN 0003-3022, E-ISSN 1528-1175, Vol. 121, no 1, p. 52-58Article in journal (Refereed)
    Abstract [en]

    Background: Remifentanil is widely used for monitored anesthesia care in spontaneously breathing patients. However, the authors' previous studies have shown that remifentanil induces subjective swallowing difficulties, which may increase the risk of aspiration.

    Methods: Twenty-five healthy volunteers participated in a double-blind, randomized, crossover trial at the University Hospital in orebro, orebro, Sweden. The volunteers were studied on two different occasions during which they received either remifentanil with an effect-site target concentration of 3 ng/ml or saline over 1 h. A radionuclide tracer was infused simultaneously into the nasopharynx at a rate of 0.1 ml/min. Aspiration was determined by lung scans, and subjective swallowing difficulties and grip strength were evaluated. The primary outcome was the difference in occurrence of aspiration between remifentanil and placebo treatments. The secondary outcomes were differences in swallowing difficulty and grip strength and the association between aspiration and swallowing difficulty.

    Results: During remifentanil and placebo infusion, 48 and 12% of the volunteers aspirated, respectively, difference: 36% (95% CI, 10 to 62%). A similar significant difference was found for swallowing difficulties but not for the association between aspiration and swallowing. No difference was found in grip strength between the two treatments.

    Conclusions: Remifentanil infusion at concentrations used in monitored anesthesia care increases the incidence of aspiration. However, the subjective swallowing difficulty induced by remifentanil is not indicative of the aspiration risk.

  • 36.
    Savvopoulos, Christos
    et al.
    Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology.
    99mTc-MIBI Embolus in the Late Phase of a Parathyroid Scan2019In: Clinical Nuclear Medicine, ISSN 0363-9762, E-ISSN 1536-0229, Vol. 44, no 8, p. 655-656Article in journal (Other academic)
    Abstract [en]

    We report a case of a transient focal MIBI uptake in the late, 90 minutes postinjection phase of a parathyroid scintigraphy in which SPECT/CT imaging proved valuable in delineating the nature of this incidental finding.

  • 37.
    Simard, Trevor
    et al.
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Hibbert, Benjamin
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Natarajan, Madhu K.
    Division of Cardiology, Hamilton Health Sciences, Hamilton ON, Canada.
    Mercuri, Mathew
    Division of Cardiology, Hamilton Health Sciences, Hamilton ON, Canada; Division of Cardiology, Department of Medicine, Columbia University, New York NY, USA.
    Hetherington, Simon L.
    Kettering General Hospital, Kettering, United Kingdom.
    Wright, Robert
    James Cook University Hospital, Middlesbrough, United Kingdom.
    Delewi, Ronak
    Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
    Piek, Jan J.
    Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
    Lehmann, Ralf
    Johann Wolfgang Goethe-University, Frankfurt, Germany.
    Ruzsa, Zoltán
    Cardiac and Vascular Center, Semmelweis University, Budapest, Hungary.
    Lange, Helmut W.
    Kardiologisch-Angiologische Praxis Herzzentrum, Bremen, Germany.
    Geijer, Håkan
    Örebro University, School of Medical Sciences. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Sandborg, Michael
    Radiation Physics, Department of Medical and Health Sciences, Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
    Kansal, Vinay
    Faculty of Undergraduate Medicine, University of Ottawa, Ottawa ON, Canada.
    Bernick, Jordan
    Cardiovascular Research Methods Center, Ottawa ON, Canada.
    Di Santo, Pietro
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Pourdjabbar, Ali
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Ramirez, F. Daniel
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Chow, Benjamin J. W.
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Chong, Aun Yeong
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Labinaz, Marino
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    Le May, Michel R.
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada.
    O'Brien, Edward R.
    Libin Cardiovascular Institute of Alberta, Calgary AB, Canada.
    Wells, George A.
    Cardiovascular Research Methods Center, Ottawa ON, Canada.
    So, Derek
    Division of Cardiology, University of Ottawa Heart Institute, Ottawa ON, Canada .
    Impact of Center Experience on Patient Radiation Exposure During Transradial Coronary Angiography and Percutaneous Intervention: A Patient-Level, International, Collaborative, Multi-Center Analysis2016In: Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, ISSN 2047-9980, E-ISSN 2047-9980, Vol. 5, no 6, article id e003333Article in journal (Refereed)
    Abstract [en]

    Background: The adoption of the transradial (TR) approach over the traditional transfemoral (TF) approach has been hampered by concerns of increased radiation exposure-a subject of considerable debate within the field. We performed a patient-level, multi-center analysis to definitively address the impact of TR access on radiation exposure.

    Methods and Results: Overall, 10 centers were included from 6 countries-Canada (2 centers), United Kingdom (2), Germany (2), Sweden (2), Hungary (1), and The Netherlands (1). We compared the radiation exposure of TR versus TF access using measured dose-area product (DAP). To account for local variations in equipment and exposure, standardized TR:TF DAP ratios were constructed per center with procedures separated by coronary angiography (CA) and percutaneous coronary intervention (PCI). Among 57 326 procedures, we demonstrated increased radiation exposure with the TR versus TF approach, particularly in the CA cohort across all centers (weighted-average ratios: CA, 1.15; PCI, 1.05). However, this was mitigated by increasing TR experience in the PCI cohort across all centers (r=-0.8; P=0.005). Over time, as a center transitioned to increasing TR experience (r=0.9; P=0.001), a concomitant decrease in radiation exposure occurred (r=-0.8; P=0.006). Ultimately, when a center's balance of TR to TF procedures approaches 50%, the resultant radiation exposure was equivalent.

    Conclusions: The TR approach is associated with a modest increase in patient radiation exposure. However, this increase is eliminated when the TR and TF approaches are used with equal frequency-a guiding principle for centers adopting the TR approach.

  • 38. Souza, Domingos S. R.
    et al.
    Johansson, Benny
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden.
    Bojoe, Leif
    Karlsson, Roland
    Geijer, Håkan
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Filbey, Derek
    Bodin, Lennart
    Örebro läns landsting.
    Arbeus, Mikael
    Dashwood, Michael R.
    Harvesting the saphenous vein with surrounding tissue for CABG provides long-term graft patency comparable to the left internal thoracic artery: results of a randomized longitudinal trial2006In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 132, no 2, p. 373-U75Article in journal (Refereed)
    Abstract [en]

    Objective: Conventional harvesting of the saphenous vein in coronary artery bypass surgery produces vessel damage that contributes to graft failure. A novel "no touch" technique provides high short- and long-term patency rates.

    Method: This randomized longitudinal trial compares graft patency of two patient groups undergoing coronary artery bypass surgery. Conventional: 52 patients had their veins stripped, distended, and stored in saline solution. No-touch: 52 patients had veins removed with surrounding tissue, not distended, and stored in heparinized blood. Angiographic assessment was performed at mean time 18 months after the operation in 46 patients in the conventional group and 45 patients in the no-touch group and repeated at mean time 8.5 years in 37 patients from both groups.

    Results: The distribution of the grafts to the recipient coronary arteries regarding their size and quality was similar in both groups. The angiographic assessment at 18 months postoperatively showed 89% conventional versus 95% no-touch grafts were patent. Repeated angiography at 8.5 years showed a patency rate for the conventional group of 76% and 90% for the no- touch group ( P =.01). The multivariate analysis showed that the most important surgical factors for graft patency were the technique of harvesting ( odds ratio = 3.7, P =.007) for the no- touch versus the conventional technique and the vein quality before implantation ( odds ratio = 3.2, P =.007) for veins that were of good quality. By comparison the patency of the thoracic artery grafts was 90%.

    Conclusion: Harvesting the saphenous vein with surrounding tissue provides high short- and long-term patency rates comparable to the left internal thoracic artery.

1 - 38 of 38
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