Interpolating scan and oblique-angle tomograms in myocardial PET using nitrogen-13 ammonia

The effect of low sensitivity areas or gaps between adjacent slices of the multislice positron emission tomography on detection of myocardial perfusion abnormality with 13NH3 was evaluated segmentally in 36 patients with coronary artery disease at rest or during exercise. The detectability of the defects in RCA or LAD region was 80% in single-position scans in stress studies. The false-negative defects were located mainly in the inferior wall, apicoinferior wall, or high anterior wall. When the patients were moved half the slice interval to perform the interpolating scan, and the two sets of images were interlaced with each other, the detectability increased to 88%. The interpolating scan also allowed reconstruction of long-axis and short-axis tomograms in high quality, which further improved the detectability of perfusion defects (100% for RCA or LAD and 75% for LCX lesion) and helped in understanding the anatomic relationships to the coronary artery territories.