Assessment of aorto-coronary bypass graft patency and graft flow by contrast enhanced computed tomography
Hayase, S.; Shimizu, T.; Iriyama, T.; Nakajima, M.; Aida, H.; Iwanami, H.; Sakamoto, S.; Anzai, Y.; Watanabe, K.; Yuasa, K.
Nihon Kyobu Geka Gakkai 32(3): 307-314
1984
ISSN/ISBN: 0369-4739 PMID: 6611381 Document Number: 230778
Recent advances in computed tomography have led to clinically useful imaging of the cardiovascular structures with remarkable resolution. In 44 patients with 66 aorto-coronary bypass grafts, the efficacy of contrast enhanced computed tomography [CECT] to determine graft patency and estimate graft flow was studied. After the proper scanning level was selected by scout scans, sequential scans with a 5 s scanning time and a 5 s interscan period were performed during the rapid injection of a 30 ml bolus of contrast medium into an antecubital vein. Patency of grafts was determined by a characteristic enhancement with contrast medium that coincides with appearance of contrast in the aorta. Comparing CECT with conventional graft angiography, results gave a 91% sensitivity for CECT detection of graft patency, a 91% specificity and a 91% accuracy. Variables, such as follows, were measured by plotting the time-density curve of dynamic scans. .DELTA.CT = increasing rate of CT number, Max CT = peak CT number -.DELTA.CT = clearance rate of CT number. The mean graft flow was measured intraoperatively by using an electromagnetic flowmeter. To determine if CECT can quantitate graft flow, correlation between the mean graft flow and variables was studied. There was significant correlation between the mean graft flow and -.DELTA.CT of graft/-.DELTA.CT of Ao. (P < 0.001). CECT has promise as a safe and relatively noninvasive technique for determining bypass graft patency and estimating graft flow.