Fig 1.
Schematic representation of workflow from imaging through to strain analysis.
16 short-axis cardiac MRI stacks were used from one specimen. Endocardial contours were traced in three software packages ScanIP, OsiriX, and Circle CVI42. Short-axis slices were grouped into three regions apex, mid-ventricle, and base, and regional circumferential strains were calculated as the average over slices in the region. Global circumferential strain, end-diastolic and end-systolic volumes, and left ventricular ejection fraction were also calculated.
Fig 2.
Visual comparison of contouring approaches in ScanIP and Osirix.
A. Contour representation in ScanIP. Pixels within the endocardium are selected (based on thresholding or manual selection), to be exported in a binary image format. B. Contour representation in OsiriX. Contours markers are placed at points around the endocardium, and a spline curve is interpolated between these points.
Table 1.
Means, standard deviations, standard deviation as a percentage of the mean, and 95% confidence intervals for all variables in each software package for both repetitions.
Table 2.
The paired mean data across the users of the paired repetitions and software.
Fig 3.
Boxplots of peak data for the four circumferential strain variables investigated.
a) apical circumferential strain, b) mid-ventricular circumferential strain, c) basal circumferential strain, d) global circumferential strain. The circles represent data from individual readers. T1 and T2 are the first and second repetition of contouring in a given software. Equivalent data from CVI42 is shown in the fifth column.
Fig 4.
Boxplots of peak data for the three clinical volume variables investigated.
a) end diastolic volume, b) end systolic volume, c) left ventricular ejection fraction. The circles represent data from individual readers. Equivalent data from CVI42 is shown in the fifth column.
Fig 5.
Bland-Altman analyses of differences in endocardial contour lengths measured in ScanIP, OsiriX, and CVI42.
Results from test 1 and test 2 from ScanIP and OsiriX are shown. The CVI42 data was assumed to be 100% repeatable, and thus the same data was used for both tests 1 and 2, as previously described.