SUPPRESSION OF VENOUS SIGNAL IN TIME-OF-FLIGHT MR-ANGIOGRAPHY OF THE LOWER-EXTREMITIES AFTER ADMINISTRATION OF GADOPENTETATE DIMEGLUMINE

PURPOSE: To evaluate a magnetic resonance (MR) angiography time-of-nig ht technique that can effectively suppress venous signal after gadopen tetate dimeglumine administration. MATERIALS AND METHODS: Twelve adult patients underwent MR angiography for the evaluation of peripheral va scular disease. Gradient-echo sequences were performed after the admin istration of 0.2 mmol/kg gadopentetate dimegiumine. Three sequences we re compared: a nontriggered sequence; a gap sequence, an electrocardio graphically triggered, segmented sequence with a 7-mm gap between satu ration and imaging sections; and a no-gap sequence, a similar sequence as gap but with partially overlapping imaging and saturation sections . For each sequence, identical regions of interest were generated for arterial, venous, and background muscle tissue and noise. A paired Stu dent t test was used to compare the signal-to-noise and contrast-to-no ise ratios (C/Ns) among the sequences. In seven patients, the no-gap s equence was used to acquire MR angiograms of the distal lower extremit ies. RESULTS: The mean artery-muscle C/N was similar for the triggered sequences; both were statistically significantly greater than the rat ios for the nontriggered sequence. Venous suppression was much better with the no-gap sequence. Overall, the best artery-vein C/N was also o btained with the no-gap sequence. MR angiograms with effective venous suppression could be obtained only with the no-gap sequence. CONCLUSIO N: Time-of-flight MR angiograms can be obtained with effective venous suppression after the administration of 0.2 mmol/kg gadopentetate dime glumine.