clinical applications of virtual, non-contrast head images derived from dual-source, dual-energy cerebrovascular computed tomography angiography

Background: this study set out to evaluate the utility of cerebrovascular virtual noncontrast (vnc) scans. materials and methods: conventional noncontrast (cnc) and dualenergy computed tomography angiography (decta) head scans were conducted on 100 subjects, of which 46 were normal, 15 had parenchymal hematomas of the brain, 13 had ischemic infarction, 22 had tumors, and 4 had calcified lesions. vnc images were extracted from the decta head scans by postprocessing. the true (or conventional) and vnc images were compared in terms of the mean ct attenuation value and signaltonoise ratio (snr) of the cerebral parenchyma, the image quality, the lesion detection sensitivity, and the radiation exposure level. results: the image qualities of the cnc and vnc scans were (4.95 plusmn; 0.22) points and (3.94 plusmn; 0.24) points (t = 31.18, p lt; 0.05), the mean ct values for the cnc and vnc images were (34.6 plusmn; 2.44) and (28.6 plusmn; 5.40) hu (t = 10.126, p lt; 0.05), the snrs were (9.45 plusmn; 1.26) and (6.87 plusmn; 1.77), and the hu for white matter was (t = 11.859, plt;0.05), respectively. the effective radiation doses from the decta head scans and the conventional noncontrast scans were (8.55 plusmn; 0.57) msv and (9.41 plusmn; 1.00) msv, respectively. no significant difference in the lesion detection sensitivities was observed between the cnc and vnc scans, except for tiny calcified lesions, which could not be identified by a vnc scan. conclusion: vnc and contrastenhanced images could be obtained from decta head scans and could aid in the diagnosis of cerebral lesions. the radiation dose from the vnc scan was less than that from the cnc scan.