The prolate spheroidal transform for the gated SPECT

Suggests a way to calculate the volume and surface area of left ventricle (LV) in the Prolate Spheroidal Coordinate (PSC) system. The advantages of this method are: (1) Due to the approximate ellipsoid shape of LV, the /spl zeta/ axis is perpendicular to the LV surfaces in the prolate spheroidal (/spl zeta/, /spl theta/, /spl phi/) coordinate system, the small elements used in volume and area calculations fit the geometry, even in the apex region with large curvature. (2) The authors don't need to align the LV with their coordinate system in order to get good results. This method requires the origin of the PSC system to be inside the LV cavity. The authors applied the prolate spheroidal transform to the short axis gated SPECT data and calculated the volumes of LV using the midmyocardium. Also they calculated the areas of the midmyocardial surface. The authors verified the method with the MCAT phantom and applied it to a patient case. In conclusion, the calculations of the LV volume and surface areas can be more easily performed in the PSC system. There exist good correlations between the calculated volume and surface area values, which implies that the calculation of surface area may be a possible way to estimate the volume of the LV.