Fig. 7

Transient interruption of contrast bolus results in suboptimal opacification of the pulmonary artery on initial contrast bolus, with subsequent diagnostic scan for pulmonary embolus after repeat injection using high pitch FLASH CTA. The initial CECT (a) shows poor opacification of the pulmonary artery despite high density contrast material within the aorta and SVC because deep inspiration resulted in increased venous return from the IVC and dilution of the contrast bolus in the right heart (b) at the time of scanning. Repeat injection using high pitch FLASH technique with free breathing (c) shows excellent opacification of the pulmonary artery