Accurate three-dimensional wall thickness measurement from multi-slice short-axis MR imaging

In multiple slice, multiple phase short-axis MR images of the left ventricle the cardiac wall and imaging plane are often at an oblique angle. Planar wall thickness measurements will consequently not be measured perpendicular to the myocardial wall, and therefore overestimate true wall thickness. To correct for this deficiency a three-dimensional wall thickness calculation algorithm has been developed, based on the planar improved centerline method. Evaluation was carried out using software phantoms and MR imaging studies obtained from twenty healthy individuals. When applied to the software phantoms the 3D method demonstrated an error of only 1.6% at the mid to low slices and 10.6% at the apex, compared to errors of 8.1% and 28.6% with the planar method, respectively. In patient studies 3D wall thickness results at apical, low and mid slices were 11.2%, 8.7% and 2.6% smaller than the corresponding 2D values. In conclusion, this three-dimensional approach significantly improves the assessment of cardiac wall thickness measurements from short-axis MR studies.