Quantitative and qualitative evaluation of low-dose craniocervical computed tomography angiography with a lower tube voltage protocol

BackgroundCraniocervical computed tomography angiography (CCCTA) is widely used for the clinical assessment of craniocervical vessels. PurposeTo investigate and compare the image quality and radiation doses associated with lower-dose (100 and 80 kVp) CCCTA protocols versus the conventional 120-kVp protocol. Material and MethodsThis study enrolled 120 patients and randomly divided them into three groups: group A = 120 kVp; group B = 100 kVp; and group C = 80 kVp. Patients in all three groups were scanned in a 256-slice CT machine at a slice thickness of 0.625 mm. We compared the quantitative and qualitative image quality and radiation doses among the groups. The κ test was used to estimate the inter-observer reliability of image quality evaluations performed independently by two experienced radiologists. ResultsArterial attenuation of the head, neck, and shoulder regions was significantly higher in both groups B and C than in group A. In addition, no significant inter-group differences were observed in the signal-to-noise ratio or contrast-to-noise ratio in the head and neck regions. Both groups B and C had a lower CT dose index and dose-length product relative to group A. Regarding subjective image quality, group B yielded significantly better image quality than group A and C, while groups A and C did not differ significantly. The subjective quality analysis had good inter-observer reliability (κ = 0.785). ConclusionIn CCCTA, the 100-kVp protocol increased arterial enhancement, reduced the radiation dose, and would not cause prominent streak artifacts. This protocol should be considered for CCCTA.