Diffusion-Weighted MR Imaging after Carotid Artery Stenting

Park, Ju Hyun; Kim, Eui Jong; Koh, Jun Seok; Ryu, Chang Woo; Choi, Woo Suk

Abstract

PURPOSE
New Diffusion abnormalities of brain parenchyme are not infrequent after carotid artery angioplasty and stenting(CAS). Purpose of this study is to evaluate the changes of diffusion-weighted imaging(DWI) in pre- and post-carotid artery stenting (CAS) in patients with severe carotid stenosis regardless of use of distal protection devices.
MATERIALS AND METHODS
Between January 2003 and December 2005, 51 cases of CAS were performed. Among these 30 cases (27 patients, 63.9 years-old, 25 males and 2 females) undergoing CAS with pre- and poststenting DWI were evaluated. 25 CAS procedures were performed under distal protection, and remained 5 CAS procedures were done without use of distal protection device. In all cases, MR imaging was performed a week before and after CAS. The new lesions were defined as the lesions that were present only on the postprocedural DWI. The incidence, numbers, size and location (vascular territory) of the new lesions after stent placement, were accessed on DWI. A study on the relationships between the new lesions and the patient's age, the type of stent or filter device and neurologic symptoms was conducted.
RESULTS
New lesions on DWI were detected in 14 of 30 cases (46.7%). In 13 cases, the reported number of microembolism foci was 43 (mean 6.4 mm in size), and one patient showed diffuse bilateral watershed infarction. Among them, 19 foci (44.2%) were in ipsilateral vascular territory, but 24 foci (55.8%) were not. The new lesions were not related to the patient's age, site of stenosis, and stent or filter types. Three patients had neurologic symptoms after CAS. Two of them had improved, but one case with watershed infarction related with myocardial infarction had remained neurologic sequalae. All three these cases showed multiple new lesions after CAS.
CONCLUSION
New lesions on DWI after CAS are observed not only in the ipsilateral vascular territory but also in other locations as well. This suggests that cause of the new lesions might be any step in the procedure and not just the absence of distal protection devices. The incidence of microembolic events of CAS with or without use of distal protection devices was not low, but clinical symptoms with neurologic sequelae are rare.