Aim: To develop and validate a method for diagnosing left ventricular (LV) hypertrophy from cardiac perfusion 15O-water positron emission tomography (PET).
Methods:This was a retrospective study with pooled data from 139 subjects in four research cohorts. LV remodeling patterns ranged from normal to severe eccentric and concentric hypertrophy. 15O-water PET scans (n=197) were performed with three different PET devices. Data from a low-end scanner (66 scans) were used for method development, remaining scans were used for a blinded evaluation. Dynamic data were converted into parametric images of perfusable tissue fraction for semi-automatic delineation of the LV wall in the short axis view. The enclosed region was used to calculate LV mass (LVM) and septal wall thickness (WT). LVM and WT from PET were compared to cardiac magnetic resonance (CMR, n=47) and WT to 2D-echocardiography (2DE, n=36). PET accuracy was tested using linear regression, Bland-Altman plots, and ROC curves. Observer reproducibility were evaluated using intraclass correlation coefficients.
Results: Correlations (PET-LVM and PET-WT towards CMR; PET-WT towards 2DE) were high (r≥0.87, P<0.0001 for all) with high-end scanners, and slightly lower for LVM (r=0.84) and WT (r=0.76, both P<0.0001) with a low-end scanner. There was no significant bias for WT, but a proportional bias for LVM was found. The area-under-the-curve for blinded detection of increased LVM and WT (>12 mm and >15 mm) diagnosed by conventional imaging was ≥0.95 (P<0.0001 for all). Reproducibility was excellent (ICC ≥ 0.93, P<0.0001).
Conclusion: 15O-water PET might detect LV hypertrophy with high accuracy and precision.