Low-dose Contrast-enhanced Magnetic Resonance Angiography with Less than the Standard Dose of Gadolinium Chelate: Comparison with Conventional Digital Subtraction Angiography

ABSTRACT

PURPOSE: To evaluate the effectiveness of contrast-enhanced MR angiography (CEM-RA)using gadolinium chelate at less than the standard dose. MATERIALS AND METHODS: Eight patients with occlusive arterial disease underwent 16 CEMRA scans of the lower extremities following bolus injection of 0.075 mmol/kg gadolinium, using a 1.5T scanner and 3D-turbo-FLASH sequence. The arterial phase was compared with that obtained by digital subtraction angiography (DSA). After grouping arteries according to their diameter, arterial detectability (AD), stenosis grad-ing (SG), and the detectability of significant stenosis (SD) were compared. RESULTS: The AD of CEMRA showed high specificity (Sp, 98%-100%) in all groups, and sensitivity (Sn) was high (>90%) in groups I, II, and III. SG showed a correlation coefficient of 0.65* and 0.60* in groups I and II, though CEMRA tended to overesti-mate. SD was high (Sn,100%) in all groups, but Sp was low(<70%). CONCLUSION: Low-dose CEMRA is an excellent way to exclude significant arterial ob-struction in the lower extremities, even in small arteries. Stenosis grading was possible in large arteries but consideration must be paid to the technique 's overestimating characteristic.