Gadolinium-enhanced three-dimensional MR angiography before endovascular treatment of aneurysms in the abdominal aorta, iliac and peripheral vessels

Purpose: The value of DSA for the measurement of aortic and peripheral arterial aneurysm dimensions before endovascular treatment is limited by projection effects. It was evaluated if additional gadolinium-enhanced three-dimensional MR angiography (3D-CEMRA) could compensate for the disadvantages of D5A. Materials and Methods: 21 patients with 35 aneurysms in the abdominal aorta (14), iliac (9) and femoropopliteal vessels (12) were assessed with DSA (7 with calibrated catheter, 14 with yardstick) and 3D-CEMRA (TR/TE 7.8/2.1 ms, flip-angle 40 degrees, Matrix 512 x 224, FOV 500 mm, eff. slice 1.8 mm). We measured and compared aneurysm dimensions on both modalities. 3D-CEMRA was regarded as the reference method to evaluate the dimension of DSA-projection effects. Results: Diameter and length of aneurysms were underestimated on DSA with the yardstick as reference. The deviation ranged from 15% (+/-5%) in the aorta to 21% (+/-10%) in the iliac vessels. Only with calibrated catheters as reference (7/21 DSA), were the distances on DSA correlated well with MRA. In 2/35 aneurysms 3D-CEMRA detected thrombosis with a difference between length of inner lumen dilatation on DSA and whole aneurysm length. 2/5 accessory renal arteries found on DSA were not detected on 3D-CEMRA. Conclusions: 3D-CEMRA is a valuable adjunct to DSA for pre-interventional diagnostics of aortic and peripheral arterial aneurysms. It provides exact evaluation of aneurysm dimensions and information about partial thrombosis.