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

Abstract

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 (3–5L/min, steps of 0.5L/min) using an extracorporeal cardiac pump. Vascular enhancement of the thoraco-abdominal aorta was measured every 5cm. 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 3.5L/min vs. 5L/min (484±25HU vs. 476±19HU, p=.14) and 4 vs. 5L/min (443±49HU vs. 476±19HU, 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.