Cvi42 post processing software

The UK Biobank CMR protocol has been described in detail elsewhere [18 (link)]. Briefly, all examinations were performed on a wide-bore 1.5 Tesla scanner (MAGNETOM Aera, Syngo Platform VD13A, Siemens Healthcare, Erlangen, Germany). For cardiac function, long-axis cines and a complete short-axis stack of balanced steady-state free precession (bSSFP) cines, covering the left and right ventricle were acquired.
Typical parameters were as follows: TR/TE = 2.6/1.1ms, flip angle 80°, Grappa factor 2, voxel size 1.8 mm x 1.8 mm x 8 mm (6 mm for long axis). The actual temporal resolution of 32 ms was interpolated to 50 phases per cardiac cycle (~20 ms). No signal or image filtering was applied besides distortion correction.
Analysis of the left ventricle (LV), right ventricle (RV), left atrium (LA) and right atrium (RA) for all CMR examinations were performed manually by observers across two core laboratories according to pre-approved standard operating procedures using cvi⁴² post-processing software (Version 5.1.1, Circle Cardiovascular Imaging Inc., Calgary, Canada). LV papillary muscles were included in blood pool volumes and excluded from LV mass. Detailed descriptions of analysis methodology, including exemplar contours and intra- and inter-observer variability, have been previously described [19 (link)].

CMR scans of the first 5,065 UKB participants that completed the imaging study were manually analyzed across two core laboratories (London, Oxford) using a pre-defined standard operating procedure, which is detailed elsewhere (22 (link)). In brief, left and right ventricular (LV, RV) endocardial contours and LV epicardial contours were drawn in end-systole and end-diastole on the short axis stack images using the CVI42 post-processing software (Version 5.1.1, Circle Cardiovascular Imaging Inc., Calgary, Canada). These contours were used to define three regions of interest (ROIs) for radiomics analysis: RV blood pool, LV blood pool, and LV myocardium. All acquisitions were ECG gated and thus end-diastole was defined as the first phase in the sequence. End-systole was defined as the frame with smallest LV cavity area by visual assessment detected at the mid-cavity level. Papillary muscles were considered part of the blood pool. Slices with more than 50% circumferential LV myocardium were included in LV contours. RV volume was defined as areas below the pulmonary valve plane identified by visual assessment.

The UK Biobank CMR protocol has been described in detail elsewhere [16 (link)]. Briefly, all examinations were performed on a wide-bore 1.5 Tesla scanner (MAGNETOM Aera, Syngo Platform VD13A, Siemens Healthcare, Erlangen, Germany). For cardiac function, long axis cines and a complete short axis stack of balanced steady-state free precession (bSSFP) cines, covering the left and right ventricle were acquired.
Analysis of the cardiac chambers for all CMR examinations was performed manually across two core laboratories according to pre-approved standard operating procedures using cvi⁴² post-processing software (Version 5.1.1, Circle Cardiovascular Imaging Inc., Calgary, Canada) by observers blinded to all exposures. LV papillary muscles were included in blood pool volumes and excluded from LV mass. Detailed descriptions of analysis methodology, including reference ranges, exemplar contours and intra- and inter-observer variability, have been previously described [17 (link)]. The CMR parameters examined in this study were left ventricular end-diastolic volume, end-systolic volume, stroke volume, ejection fraction and mass and left atrial maximal volume.