Thoraco-abdominal high-pitch dual-source CT angiography: Experimental evaluation of injection protocols with an anatomical human vascular phantom

ObjectiveTo experimentally evaluate three different contrast injection protocols at thoraco-abdominal high-pitch dual-source computed tomography angiography (CTA), with regard to level and homogeneity of vascular enhancement at different cardiac outputs.Materials and methodsA uniphasic, a biphasic as well as an individually tailored contrast protocol were tested using a human vascular phantom. Each protocol was scanned at 5 different cardiac outputs (3-5 L/min, steps of 0.5 L/min) using an extracorporeal cardiac pump. Vascular enhancement of the thoraco-abdominal aorta was measured every 5 cm. Overall mean enhancement of each protocol and mean enhancement for each cardiac output within each protocol were calculated. Enhancement homogeneity along the z-axis was evaluated for each cardiac output and protocol.ResultsOverall mean enhancement was significantly higher in the uniphasic than in the other two protocols (all p < .05), whereas the difference between the biphasic and tailored protocol was not significant (p = .76). Mean enhancement among each of the 5 cardiac outputs within each protocol was significantly different (all p < .05). Only within the tailored protocol mean enhancement differed not significantly at cardiac outputs of 3.5 L/min vs. 5 L/min (484 ± 25 HU vs. 476 ± 19 HU, p = .14) and 4 vs. 5 L/min (443 ± 49 HU vs. 476 ± 19 HU, p = .05). Both, uniphasic and tailored protocol yielded homogenous enhancement at all cardiac outputs, whereas the biphasic protocol failed to achieve homogenous enhancement.ConclusionThis phantom study suggests that diagnostic and homogenous enhancement at thoraco-abdominal high-pitch dual-source CTA is feasible with either a uniphasic or an individually tailored contrast protocol.