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Publications (10 of 10) Show all publications
Al-Ubeidy, H., Alshamari, M., Widell, J., Eriksson, T. & Lidén, M. (2019). High-pitch, low-kVp computed tomography for ruling out pulmonary embolism with 17-mL contrast media. In: : . Paper presented at European Conference of Radiology (ECR), Vienna, Austria, 2019.
Open this publication in new window or tab >>High-pitch, low-kVp computed tomography for ruling out pulmonary embolism with 17-mL contrast media
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2019 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:oru:diva-73820 (URN)
Conference
European Conference of Radiology (ECR), Vienna, Austria, 2019
Available from: 2019-04-16 Created: 2019-04-16 Last updated: 2019-04-16Bibliographically approved
Jendeberg, J., Geijer, H., Alshamari, M. & Lidén, M. (2018). Prediction of spontaneous ureteral stone passage: Automated 3D-measurements perform equal to radiologists, and linear measurements equal to volumetric. European Radiology, 28(6), 2474-2483
Open this publication in new window or tab >>Prediction of spontaneous ureteral stone passage: Automated 3D-measurements perform equal to radiologists, and linear measurements equal to volumetric
2018 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 28, no 6, p. 2474-2483Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Computed tomography, Ureteral calculi, Kidney stone, Ureter, Renal colic
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:oru:diva-64712 (URN)10.1007/s00330-017-5242-9 (DOI)000431653200024 ()29368161 (PubMedID)
Note

Funding Agency

Research Committee of Region Orebro County 

Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-08-20Bibliographically approved
Alshamari, M., Geijer, M., Norrman, E., Lidén, M., Krauss, W., Jendeberg, J., . . . Geijer, H. (2017). Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine. Acta Radiologica, 58(6), 702-709
Open this publication in new window or tab >>Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine
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2017 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 58, no 6, p. 702-709Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
London: Sage Publications, 2017
Keywords
X-ray computed tomography (CT), image manipulation/reconstruction, lumbar vertebrae, radiation dosage, spine
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:oru:diva-57646 (URN)10.1177/0284185116669870 (DOI)000399995700011 ()28157395 (PubMedID)2-s2.0-85019010032 (Scopus ID)
Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2019-03-26Bibliographically approved
Jendeberg, J., Geijer, H., Alshamari, M., Cierzniak, B. & Lidén, M. (2017). Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage. European Radiology, 27(11), 4775-4785
Open this publication in new window or tab >>Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage
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2017 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 27, no 11, p. 4775-4785Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Spiral computed tomography; Ureteral calculi; Kidney stone; Ureter; Renal colic
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:oru:diva-61961 (URN)10.1007/s00330-017-4852-6 (DOI)000412820500037 ()28593428 (PubMedID)2-s2.0-85020305726 (Scopus ID)
Note

Funding Agency:

Research Committee of Region Örebro County

Available from: 2017-10-26 Created: 2017-10-26 Last updated: 2018-08-07Bibliographically approved
Alshamari, M., Norrman, E., Geijer, M., Jansson, K. & Geijer, H. (2016). Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review. European Radiology, 26(6), 1766-1774
Open this publication in new window or tab >>Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review
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2016 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 26, no 6, p. 1766-1774Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
New York: Springer, 2016
Keywords
X-ray computed tomography, abdominal radiography, sensitivity and specificity, abdominal pain, abdomen, acute
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Radiology
Identifiers
urn:nbn:se:oru:diva-47089 (URN)10.1007/s00330-015-3984-9 (DOI)000376100100030 ()26385800 (PubMedID)2-s2.0-84942013953 (Scopus ID)
Note

Funding Agency:

Region Örebro County

Available from: 2015-12-16 Created: 2015-12-16 Last updated: 2019-03-26Bibliographically approved
Alshamari, M., Geijer, M., Norrman, E., Lidén, M., Krauss, W., Wilamowski, F. & Geijer, H. (2016). Low dose CT of the lumbar spine compared with radiography: a study on image quality with implications for clinical practice. Acta Radiologica, 57(5), 602-611
Open this publication in new window or tab >>Low dose CT of the lumbar spine compared with radiography: a study on image quality with implications for clinical practice
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2016 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 57, no 5, p. 602-611Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
London, United Kingdom: Sage Publications, 2016
Keywords
Radiation dose, radiography, tomography, X-ray computed, axial skeleton
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Radiology
Identifiers
urn:nbn:se:oru:diva-47090 (URN)10.1177/0284185115595667 (DOI)000374327600014 ()26221055 (PubMedID)
Available from: 2015-12-16 Created: 2015-12-16 Last updated: 2019-03-26Bibliographically approved
Alshamari, M. (2016). Low-dose computed tomography of the abdomen and lumbar spine. (Doctoral dissertation). Örebro: Örebro university
Open this publication in new window or tab >>Low-dose computed tomography of the abdomen and lumbar spine
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Radiography is a common radiologic investigation despite abundant evidence of its limited diagnostic value. On the other hand, computed tomography (CT) has a high diagnostic value and is widely considered to be among the most important advances in medicine. However, CT exposes patients to a higher radiation dose and it might therefore not be acceptable simply to replace radiography with CT, despite the powerful diagnostic value of this technique. At the expense of reduced CT image quality, which could be adjusted to the diagnostic needs, low-dose CT of abdomen and lumbar spine can be performed at similar dose to radiography. The aim of the current thesis project was to evaluate low-dose CT of the abdomen and lumbar spine and to compare it with radiography. The hypothesis was that CT would give better image quality and diagnostic information compared to radiography at similar dose levels. Firstly, the diagnostic accuracy of low-dose CT of the abdomen was evaluated. Results showed that low-dose CT of abdomen has a high sensitivity and specificity compared to radiography, i.e., it has higher diagnostic accuracy. Similar results were obtained from our systematic review. Secondly, in a phantom study, an ovine phantom was scanned at various CT settings. The image quality was evaluated to obtain a protocol for the optimal settings for low-dose CT of lumbar spine at 1 mSv. This new protocol was then used in a clinical study to assess the image quality of low-dose CT of the lumbar spine and compare it to radiography. Results showed that low-dose CT has significantly better image quality than radiography. Finally, the impact of Iterative reconstruction (IR) on image quality of lumbar spine CT was tested. Iterative reconstruction is a recent CT technique aimed to reduce radiation dose and/or improve image quality. The results showed that the use of medium strength IR levels in the reconstruction of CT image improves image quality compared to filtered back projection. In conclusion, low-dose CT of the abdomen and lumbar spine, at about 1 mSv, has better image quality and gives diagnostic information compared to radiography at similar dose levels and it could therefore replace radiography.

Place, publisher, year, edition, pages
Örebro: Örebro university, 2016. p. 87
Series
Örebro Studies in Medicine, ISSN 1652-4063 ; 137
Keywords
Tomography, X-Ray Computed, Radiography, Radiation Dosage, Abdomen, Spine, Lumbosacral Region, Regression Analysis
National Category
Surgery
Research subject
Surgery
Identifiers
urn:nbn:se:oru:diva-48242 (URN)978-91-7529-104-8 (ISBN)
Public defence
2016-04-08, Universitetssjukhuset, Bohmanssonsalen, Södra Grev Rosengatan, Örebro, 13:00 (English)
Opponent
Supervisors
Available from: 2016-02-15 Created: 2016-02-15 Last updated: 2018-04-27Bibliographically approved
Jendeberg, J., Cierzniak, B., Alshamari, M., Geijer, H. & Lidén, M. (2016). Prognosis of spontaneous ureteral stone passage: as revealed by CT. In: : . Paper presented at European Congress of Radiology 2016, Vienna, Austria, 2-6 Mars, 2016.
Open this publication in new window or tab >>Prognosis of spontaneous ureteral stone passage: as revealed by CT
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2016 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:oru:diva-65846 (URN)
Conference
European Congress of Radiology 2016, Vienna, Austria, 2-6 Mars, 2016
Available from: 2018-03-16 Created: 2018-03-16 Last updated: 2018-03-16Bibliographically approved
Alshamari, M., Geijer, M., Norrman, E. & Geijer, H. (2014). Low-dose computed tomography of the lumbar spine: a phantom study on imaging parameters and image quality. Acta Radiologica, 55(7), 824-832
Open this publication in new window or tab >>Low-dose computed tomography of the lumbar spine: a phantom study on imaging parameters and image quality
2014 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 55, no 7, p. 824-832Article in journal (Refereed) Published
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.

Keywords
conventional radiography; CT; spine; structures; techniques
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Radiology
Identifiers
urn:nbn:se:oru:diva-38243 (URN)10.1177/0284185113509615 (DOI)000342575300008 ()2-s2.0-84907878366 (Scopus ID)
Available from: 2014-11-03 Created: 2014-10-30 Last updated: 2019-03-26Bibliographically approved
Alshamari, M., Geijer, M., Norrman, E., Lidén, M., Krauss, W., Jendeberg, J., . . . Geijer, H.Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine.
Open this publication in new window or tab >>Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine
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(English)Manuscript (preprint) (Other academic)
National Category
Surgery
Research subject
Surgery
Identifiers
urn:nbn:se:oru:diva-49423 (URN)
Available from: 2016-03-17 Created: 2016-03-17 Last updated: 2019-03-26Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0137-9991

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