MR-DWI–Positive Lesions and Symptomatic Ischemic Complications After Coiling of Unruptured Intracranial Aneurysms

Abstract

Downloaded from StrokeMarch 2013 infarction on MR-DWI. The incidence of SIC was 3.5% per patient (14/396). Among the patients who underwent MR-DWI, the incidence of SIC was 4.1% (14/342). All SIC developed within 12 hours posttreatment and were associated with the relevant brain. The ischemic symptoms were most severe at the beginning, but improved with time in all patients. The 1-month modified Rankin Scale scores of the 14 patients were 0 in 6, 1 in 5, 2 in 2, and 3 in 1 patient, respectively. The incidence of DWI(+) was 54.5%. The number of DWI(+) lesions was significantly larger than in the SIC group and in the asymptomatic one (12.1±10.4 versus 5.0±8.7, P<0.01). The cutoff value of DWI(+) for predicting SIC was ≥6 (sensitivity 85.7%, specificity 70.7%).The patients with DWI(+) ≥6 was 28.6% (98/343). Of the patients with SIC, the patients with DWI(+) ≥6 was 78.6% (11/14). Patients aged ≥65 had a trend for SIC, and it was the only independent risk factor for the number of DWI(+) ≥6 (Tables 1 and 2). DiscussionAlthough a few small case series reported the incidence of DWI(+) after coiling, 2,3 there has been no report about the clinical implications of such lesions. In this study, the number of DWI(+) was significantly larger in the SIC group than in the asymptomatic one. Furthermore, we found the cutoff value (≥6) of DWI(+) for predicting SIC, and these data support the higher rate of microembolism detected, as DWI(+) may be a surrogate marker for SIC.According to ATENA study, dome size ≥7 mm was significantly associated with the rate of thromboembolic complications and patients aged >60 showed significantly higher morbidity and mortality rate on univariate analysis. 4 In our study, dome size ≥7 mm and neck size ≥4 mm were significantly associated with both SIC and DWI(+) ≥6 on univariate analysis, but neither was associated with SIC or DWI(+) ≥6 in the logistic regression analysis. It may be because of low statistical power from low incidence of SIC (Tables 1 and 2). In contrast, patients aged ≥65 were significantly associated with both SIC and DWI(+) ≥6 on univariate analysis and also had a trend for SIC, and it remained the only independent risk factor for DWI(+) ≥6 in the logistic regression analysis. These data suggest that theoretically more baseline atherosclerosis and vascular tortuosity in the older patients may increase microembolisms, and in turn may increase the probability of SIC.3 Additionally, it is notable that DWI(+) lesions ≥6 was significantly higher in stent group on univariate analysis, and its P-value was close from significance in logistic regression. Contrary to expectation, antiplatelet premedication significantly increased DWI(+) lesions ≥6 on univariate analysis. Until late 2010, antiplatelet premedication had been given only to patients who had undergone stent-assisted coiling. However, stent itself may increase DWI(+) lesions ≥6, which seemed to be a compounding factor.In conclusion, the number of DWI(+) lesions was significantly larger in the SIC than in the asymptomatic group af...

Prospective Study of Early MRI Appearances following Flow-Diverting Stent Placement for Intracranial Aneurysms

“…Diffusion-positive lesions are mostly asymptomatic, but larger or more numerous lesions are associated with ischemic symptoms. 11 This was confirmed in our study with 2 of the 3 patients who had ischemic TIA or stroke with MR imaging scans showing a large number of diffusion lesions. The third patient did not have MR imaging, but an early CT scan and delayed MR imaging showed embolic changes that would certainly have been correlated with a large DWI load.…”

“…11,12 They are also increasingly recognized after open and endovascular cardiac interventions. 13,14 The degree to which they are due to gas or thrombotic or other embolic material is unknown; however, the use of heparin and air filters has been shown to reduce their incidence.…”

Association between Postprocedural Infarction and Antiplatelet Drug Resistance after Coiling for Unruptured Intracranial Aneurysms

“…Because there were only a small number (n ϭ 2) of symptomatic lesions in this study population, we assumed that multiple lesions (n Ն 6) were more severe lesions. 5 Additionally, the degree of embolization was determined by immediate postprocedural MR imaging.…”

“…[3][4][5] To reduce thromboembolic complications, many studies investigated the association between thromboembolism and aneurysm and/or patient factors. [5][6][7][8] Previous studies have demonstrated that 30%-60% of endovascular coil embolizations for unruptured aneurysms show ischemic lesions on postprocedural diffusion-weighted images. Although most of the lesions seem to be benign, some could result in permanent neurologic sequelae.…”

Microembolism after endovascular coiling of unruptured cerebral aneurysms: incidence and risk factors

“…[2][3][4]8,9,15,22,[24][25][26] Most patients who show HSI spots are asymptomatic, and the clinical significance of such spots remains controversial. However, the HSI spots reflect the presence of damaged tissue, 5,7,12,15 and their associated potential risks cannot be ignored.This study was conducted to analyze the current incidence of postprocedural DWI HSI lesions at our institution and to explore the possible risk factors for microembolic lesions visible as HSI spots on DWI after endovascular coiling of UIAs. …”