[MR dynamic subtraction angiography (MRDSA)].

We have developed magnetic resonance dynamic subtraction angiography (MRDSA), which depicts the long segments of arteries from the upper abdomen to the lower leg by using a small dose of Gd-DTPA. The lower half of the body was divided into three imaging regions, abdomen, thigh and lower leg, in the order of scanning. The contrast-enhanced three-dimensional breath-hold fast field echo technique with half Fourier acquisition was performed in 3 normal volunteers and 12 patients with vascular diseases (4: abdominal aortic aneurysm, 8: atherosclerotic occlusive disease). The images were reconstructed into composite images by using maximum-intensity-projection postprocessing after the subtraction of precontrast images. A bolus intravenous injection of a small dose of Gd-DTPA (0.02-0.05 mmol/kg) was given, followed by the five sets of scans. The acquisition time of each set was 8 to 16 seconds, and the total dose used in MRDSA was 0.1 to 0.15 mmol/kg. The image quality of MRDSA was satisfactory in 3 normal volunteers and 12 patients with vascular diseases. MRDSA demonstrated aortic aneurysm and atherosclerotic obstruction as clearly as conventional angiography. MRDSA can replace conventional angiography.