Assessment of myocardial perfusion with multi-detector computed tomography

A method to quantify the regional contrast enhancement as imaged during MDCT coronary angiography was developed. The procedure is based on the following steps: 1) Long axis reformatting and interactive selection of ventricular volume; 2) Normalization of image gray levels; 3) Extraction of the LV cavity by thresholding and blob growing; 4) LV segmentation by Fast Marching Level Set algorithm; 5) Building of bull-eye maps of the spatial distribution of contrast medium in the myocardium. The method was tested on a dataset including the scans from 10 patients with different perfusion defects. In 5 infarcted patients PET [¹³N] Ammonia scans were also performed: polar maps by CT imaging demonstrated well-defined regional perfusion defects consistent with PET imaging results.