High-Intensity Signal on Time-of-Flight Magnetic Resonance Angiography Indicates Carotid Plaques at High Risk for Cerebral Embolism During Stenting

Abstract

Background and Purpose-A major disadvantage of carotid artery stenting (CAS) compared to carotid endarterectomy is the increased risk of cerebral embolism. Thus, establishing a simple method to discriminate fragile plaques on preoperative routine examination is important. The present study examined whether high-intensity signal (HIS) in the plaque on time-of-flight (TOF) MRA, performed for screening, can discriminate plaque at high risk for cerebral embolism during CAS. Methods-In the 30 patients treated using carotid endarterectomy, relationships between pathological findings of the plaques and TOF-MRA findings were analyzed. In the 112 patients treated using CAS, postoperative ipsilateral ischemic lesions on diffusion-weighted imaging and periprocedural ischemic symptoms were analyzed. Results-The percentage area of intraplaque hemorrhage stained by glycophorin A was significantly larger in HIS-positive plaques (51.8%Ϯ9.8%) than in HIS-negative plaques (8.6%Ϯ9.4%; PϽ0.001). Postoperative ischemic lesions on diffusion-weighted imaging were more frequent in the HIS-positive plaques (25/38; 65.8%) than in the HIS-negative plaques (26/74; 35.1%; Pϭ0.002). Periprocedural ischemic symptoms were more frequently observed in HIS-positive plaques (7/38; 18.4%) than in HIS-negative plaques (1/74; 1.4%; Pϭ0.003). Multivariate logistic regression analysis identified HIS on TOF-MRA as an independent predictor of periprocedural ischemic symptoms (odds ratio, 15.08; 95% confidence interval, 1.76 -129.0). Conclusions-HIS in the plaque on TOF-MRA performed for screening could discriminate plaques at high risk for cerebral embolism during CAS. (Stroke. 2011;42:3132-3137.)Key Words: carotid endarterectomy Ⅲ carotid stenosis Ⅲ risk factors Ⅲ stenting A lthough carotid endarterectomy (CEA) is the established treatment for stroke prevention, carotid artery stenting (CAS) recently has emerged as a less invasive alternative to CEA. Two randomized controlled trials have shown that CAS and CEA offer similar efficacy, 1,2 whereas another 3 randomized studies have reported that CEA is superior to CAS. [3][4][5] Indications for CAS thus remain controversial. One of the major disadvantages of CAS is a high incidence of cerebral embolism. Recent reports described that there was an association between specific plaque components evaluated by preoperative examinations and an increased number of emboli after CAS, 6,7 and that multispectral MRI could identify plaque constituents, such as the necrotic core and intraplaque hemorrhage, with high sensitivity and specificity. 8,9 However, this examination requiring high-resolution MRI is not always available before revascularization procedures. Establishing a simple method to discriminate plaques at high risk for cerebral embolism during CAS on preoperative routine examination is important. We focused on high-intensity signal (HIS) in the plaque on time-of-flight (TOF) MRA performed for screening. The aims of this study were to validate HIS in the plaque on TOF-MRA with histology in CEA patients and t...

Effect of Pitavastatin on Preventing Ischemic Complications with Carotid Artery Stenting: A Multicenter Prospective Study—EPOCH-CAS Study

“…Several investigators, using DWI to detect clinically silent embolic lesions after protected CAS, have reported new DWI lesions at frequencies of 6.7-73 % [8,[17][18][19][20][21]. A substudy of the International Carotid Stenting Study (ICSS) reported that new DWI lesions occurred in 62 of 124 patients (50 %) in the stenting group [18].…”

“…Nakamura et al [10] reported that plaque stabilization of unstable carotid plaque significantly occurred by pitavastatin therapy within 1 month on ultrasonography. Yoshimura et al [8] reported that unstable plaque on time-of-flight MR angiography was associated with more ipsilateral ischemic lesions on DWI after CAS. One possible explanation for the lower DWIpositive rate in the PS group in this study is plaque stabilization as a consequence of the pitavastatin administration.…”

“…However, the incidence of periprocedural stroke (particularly ischemic stroke) is higher with CAS than with CEA [1,2]. Factors that influence periprocedural ischemic complications in CAS include use of a protection device, stent design, technical expertise, patient age, and plaque characteristics [3][4][5][6][7][8].…”

Carotid Intraplaque Hemorrhage Imaging: Diagnostic Value of High Signal Intensity Time-of-Flight MR Angiography Compared with Magnetization-Prepared Rapid Acquisition with Gradient-Echo Sequencing

“…However, a carotid TOF sequence has been widely used for detecting IPH because it was included in the routine protocol for brain MR examination and this approach can be time efficient, without the need for additional sequences such as MPRAGE. Maximum intensity projection (MIP) images from TOF MR angiography (MRA) can also show IPH as a high signal intensity (6,9). This finding indicates the possibility of an additional application of MIP from TOF MRA to investigate carotid artery stenosis.…”

“…The three T1-weighted sequences were two-dimensional (2D) fast spin-echo, three-dimensional (3D) time-of-flight (TOF), and threedimensional magnetization-prepared rapid acquisition gradient-echo (MPRAGE) sequence for detecting or quantifying IPH (1,(5)(6)(7)(8). Ota et al (8) reported on the diagnostic performance of three T1-weighted 3.0-T MR sequences at carotid IPH imaging, using histologic analysis as the standard of reference.…”