Experimental renal artery embolization in a combined MR imaging/angiographic unit.

摘要

PURPOSE: The purpose of this study was to use a combined x-ray angiography and MR imaging (XMR) system to manipulate intraarterial catheters and monitor the deposition of gadolinium (Gd)-impregnated embolic microspheres in vivo in a canine kidney model. MATERIALS AND METHODS: Seven anesthetized dogs (18-28 kg) were studied. The renal arteries were catheterized under fluoroscopic guidance. Renal blood flow rates were assessed with velocity-encoded cine MR imaging before and after renal artery embolization with Gd-impregnated microspheres (300-500 and 500-700 micro m in size). The particles were injected in vivo into 14 canine renal arteries under fast dynamic T1-weighted MR imaging guidance at one frame per second. Postembolic microsphere distributions were assessed with MR imaging and digital subtraction angiography (DSA). RESULTS: Gd-impregnated microsphere injection into the renal arteries was successful in all animals. Renal enhancement due to the deposition of the particles persisted for at least 1hour after the injection. The distribution of MR signal enhancement in the kidneys differed for the smaller versus the larger microspheres. The 300-500- micro m microspheres deposited preferentially in the outer cortical regions, whereas the 500-700- micro m microspheres preferentially deposited in the medulla and inner cortex. Renal blood flow was significantly reduced after the administration of both the 300-500- micro m microspheres (from 3.9 to 1.0 mL/min/g) and the 500-700- micro m microspheres (from 3.5 to 0.2 mL/min/g). CONCLUSION: MR imaging permits real-time guidance of arterial embolization with Gd-impregnated microspheres.