Semi-quantitative evaluation of cerebral blood flow with Modified Bull's Eye display using 123I-IMP SPECT

We developed Modified Bull's Eye (MBE) display to demonstrate 123I-IMP SPECT images on a single map. To compare the difference of some SPECT images, we changed the ratio of the occipitofrontal diameter to the temporal diameter of oblique SPECT images and transformed the oblique images to round-shaped images. After circumferential profile analysis (CPA) was performed on the round-shaped oblique images, the data were mapped into a polar representation (MBE display). The severity score, as the index of severity of the perfusion defect, was calculated in the same way as the myocardial SPECT. We selected five slices from the round-shaped SPECT images and divided each slice into 12 areas. The severity of the perfusion defect was scored (0-3 points) visually, and the total score was defined as the 'severity points'. We compared the severity score with the severity points for 29 patients and six normal male volunteers. The correlation coefficient of the severity score and the severity points was 0.86 (p<0.001). The MBE display makes it easy to evaluate SPECT images because it is represented on a single map, and it takes no more time to construct than the myocardial bull's eye display. It should be useful display. (author)