In this paper the computer method for evaluation of LV regional ejection fraction (REF) is described. Gated radionuclide angiocardiograms are obtained using gamma camera computer system. The computer (DJS-131) was made in China

We define Gp (x

y) as the background corrected image

then

Gp (x

y)=Fp (x

y)-Bp

Where Fp (x

y) is the image before background corrections

Bp is the background correction factor generated by the background ROI. The subscript p refers to image phase and p=0 (at ED) or p=1 (at ES). The LV ROI is subdivided in to i equiangular sections around its center of gravity (i>2). Sector 1 is marked by the long axis in opposite to the apex. REF is computed according to equation:

Where S

pi

(p=0 or1) is the number of pixels within the sector of interest (i). If we define i=8

then we can quantitatively evaluate the LV contraction functions in the following sections: posterior lateral (superior

medium

inferior)

apical

septal (superior

medium inferior).

This method has been successfully used to determine REF in 51 cases with either CAD or MI and 11 cases without heart disease.