FIG. 5.

(a) The true image with perfusion defect of 24.4 ± 5.8 HU (range, 7.8–34.3 HU) (yellow arrow). Yellow circular ROIs on the myocardium and red circular ROIs on the left ventricular blood chamber were used for the measurements. [(b) and (c)] Images reconstructed by the halfscan method (d_R = 0.5 rot) when the central angles are 0° (b) and 180° (c), respectively. Due to halfscan artifacts, the mean value of the myocardium was biased to 69.3 HU (b) and 100.8 HU (c), while the true value was 80.2 HU (a). The window width and level are 200 and 100 HU, respectively.