Whole-brain perfusion CT performed with a prototype 256-detector row CT system: Initial experience

Purpose: To preliminarily evaluate the feasibility and potential diagnostic utility of whole-brain perfusion computed tomography (CT) performed with a prototype 256-detector row CT system over an extended range covering the entire brain to assess ischemic cerebrovascular disease. Materials and Methods: Institutional review board approval and informed consent were obtained. Eleven cases in 10 subjects (six men, four women; mean age, 64.3 years) with intra- or extracranial stenosis were retrospectively evaluated with whole-brain perfusion CT. Three readers independently evaluated per- fusion CT data. The diagnostic performance of perfusion CT was visually evaluated with a three-point scale used to assess three factors. Differences between four axial perfusion CT images obtained at the basal ganglia level (hereafter, four-section images) and whole-brain perfusion CT images were assessed with the paired t test. In four subjects, the interval between perfusion CT and single photon emission computed tomography (SPECT) was 1-17 days (mean, 10.3 days). Correlation between perfusion CT findings and SPECT findings was assessed with the Spearman correlation coefficient. Results: Three-dimensional perfusion CT images and axial, coronal, and sagittal whole-brain perfusion CT images were displayed, and the extent of ischemia was assessed. Mean visual evaluation scores were significantly higher for whole-brain images than for four-section images (4.27 ± 0.76 [standard deviation] vs 2.55 ± 0.87). The cerebral blood flow ratios of the ischemic lesions relative to normal regions scanned with perfusion CT (x) and SPECT (y) showed a significant positive correlation (R ² = 0.76, y = 0.44x + 0.37, P < .001). Conclusion: Perfusion CT performed with a 256-detector row CT system can be used to assess the entire brain with administration of one contrast medium bolus. Thus, ischemic regions can be identified with one examination, which has the potential to improve diagnostic utility.