The prolate spheroidal transform for gated SPECT

Proposes a method to calculate the volume and surface area of the left ventricle (LV) in the prolate spheroidal coordinate system. The prolate spheroidal coordinate system is well suited for use with the LV due to the approximately ellipsoidal shape of the LV. The prolate spheroidal transform was applied to short axis gated SPECT data, and the volumes of the LV were calculated from the mid-myocardium surface. Also, the authors calculated the areas of the mid-myocardial surface. The information obtained may be used to estimate the LV wall thickening during a cardiac cycle. This is possible due to the fact that the myocardium is almost incompressible. The method was verified by performing tests using the MCAT phantom. The calculations of the LV volumes and surface areas of the MCAT phantoms agreed with the true values. The prolate spheroidal transform was also applied to patient gated SPECT data. Strong correlations were evident between the calculated volume and surface area values in MCAT simulations and in the patient study. These results imply that the calculation of the surface area, which is more convenient for hearts with defects, may be an alternative way to estimate the volumes of the myocardium.