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 non-contrast (vnc) scans. materials and methods: conventional non-contrast (cnc) and dual-energy computed tomography angiography (de-cta) 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 de-cta head scans by post-processing. the true (or conventional) and vnc images were compared in terms of the mean ct attenuation value and signal-to-noise 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 ± 0.22) points and (3.94 ± 0.24) points (t = 31.18, p < 0.05), the mean ct values for the cnc and vnc images were (34.6 ± 2.44) and (28.6 ± 5.40) hu (t = 10.126, p < 0.05), the snrs were (9.45 ± 1.26) and (6.87 ± 1.77), and the hu for white matter was (t = 11.859, p<0.05), respectively. the effective radiation doses from the de-cta head scans and the conventional non-contrast scans were (8.55 ± 0.57) msv and (9.41 ± 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 contrast-enhanced images could be obtained from de-cta 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.