Analysis of cardiopulmonary transit times at contrast material-enhanced MR imaging in patients with heart disease

PURPOSE: To build a database of arm-to-aorta circulation times for contrast enhancement and to determine if measured transit times can help in discrimination between patients with and patients without heart disease. MATERIALS AND METHODS: Findings at test-bolus examinations performed before acquisition of contrast material-enhanced magnetic resonance (MR) angiographic images of the head and neck were retrospectively reviewed. The times from test-bolus injection to first and peak enhancement in regions of interest were recorded in 77 patients with coronary artery disease, left ventricular hypertrophy, and/or impaired left ventricular function and 33 control subjects. Transit times in patients and control subjects were compared with Student t test. Linear regression was performed to measure the correlation coefficient. RESULTS: Transit times in patients with heart disease, including those with a normal ejection fraction, were significantly prolonged compared with those in control subjects (P < .05). Mean time to peak enhancement in the carotid artery bifurcation was 16.6 seconds ± 1.9 (SD) and 20.8 seconds ± 3.9 in control subjects and patients, respectively. Threshold value of 18 seconds for time to peak signal intensity in the carotid artery bifurcation provided highest combination of sensitivity and specificity. All (11 of 11) patients with an ejection fraction less than 40% and only three (9%) of 33 control subjects had circulation times greater than this threshold. No significant correlation was found between transit times and age, sex, weight, and height. CONCLUSION: Transit times measured with MR imaging may help in discrimination between patients with and patients without heart disease, independently of other cardiac functional parameters.