Cerebral aneurysms treated by Guglielmi detachable coils: Evaluation with diffusion-weighted MR imaging

BACKGROUND AND PURPOSE: The most frequent and serious complications of endo vascular treatment of intracranial aneurysms with Guglielmi detachable coil s (GDCs) are ischemic lesions caused by thromboembolic events. Diffusion-we ighted MR imaging appears to be the most sensitive technique for detecting early ischemic phenomena. We evaluated this technique for the detection of brain changes in patients who underwent GDC treatment of aneurysms. METHODS: Twenty patients with a cerebral aneurysm were studied with diffusi on-weighted imaging before and after endovascular treatment with GDCs, Aneu rysms were located in the anterior (n = 16) or posterior (n = 4) circulatio n. Bleeding had occurred in 11 patients. MR studies, including fast fluid-a ttenuated inversion recovery (FLAIR) and diffusion-weighted sequences, were scheduled before, 2 to 4 hours after, and 48 hours after treatment. MR ima ges, including apparent diffusion coefficient (ADC) maps, were assessed for the presence of acute ischemic stroke lesions. RESULTS: In all patients, the aneurysm was excluded without neurologic wors ening. In 18 patients, diffusion-weighted and FLAIR images showed no eviden ce of recent ischemic lesions after treatment. In one patient, an asymptoma tic frontobasal hyperintense signal on diffusion-weighted images with a dro p of ADC values corresponding to an acute ischemic lesion was observed. In another patient, multiple silent lesions were seen on diffusion-weighted im ages after embolization, These silent lesions were not all located in the v ascular territory of the aneurysm's parent artery. CONCLUSION: This preliminary study suggests that diffusion-weighted MR imag ing is a potentially useful tool for monitoring patients after endovascular treatment of a cerebral aneurysm, While small asymptomatic lesions can be observed on these images after embolization, their exact prevalence should be evaluated in a larger series.