Atherosclerosis of the carotid artery: Evaluation by magnetic resonance angiography

Wildy, Kathryn S.; Yuan, Chun; Tsuruda, Jay S.; Ferguson, Marina; Wen, Nuan; Subramaniam, Deepa; Strandness, D. Eugene

doi:10.1002/jmri.1880060505

Cited by 22 publications

(16 citation statements)

References 13 publications

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“…11,12 Validation study using surgical specimens in the present study found that intraplaque hemorrhage and macrophage infiltration were more frequent in HIS-positive plaques than in HISnegative plaques. These findings suggested that HIS on TOF- MRA indicated the plaques with fragile components leading to cerebral embolism by balloon and stent compression.…”

Section: Discussionsupporting

confidence: 52%

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

Yoshimura

Yamada

Kawasaki

et al. 2011

Stroke

139

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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...

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Section: Discussionsupporting

confidence: 52%

“…11,12 In the present study, we focused on HIS in the sagittal oblique maximum intensity projection images, rather than sectional images, on TOF-MRA ( Figure 1A). …”

Section: Mri Analysis: Tof-mramentioning

confidence: 99%

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

Yoshimura

Yamada

Kawasaki

et al. 2011

Stroke

139

View full text Add to dashboard Cite

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“…Ex vivo and in vivo MR microimaging with histologic correlates provided unique opportunity to visualize diŠerent components inside plaque such as calcium, cholesterol, connective tissue, hemorrhage etc. [4][5][6][7] The importance of plaque content analysis of silent high-grade plaques during 2 year follow up, was highlighted based on the hypothesis that plaque contents play an important role in causing plaque instability by Correia et al 8 2D and 3D high resolution ex vivo MR microimaging at 9.4T is a powerful technique to visualize distribution of cholesterol crystals, thrombi, calciˆ-cation andˆbrous material in diŠerent types of lesions in resected human tissues. 9 For it, main emphasis was focused on lipid-rich and calciˆed heterogenous regions in lesions and good registration of MR slices with histologic sections.…”

Section: Introductionmentioning

confidence: 99%

“…Clinical studies have demonstrated the use of projection in MRA studies to measure the luminal area to measure the degree of luminal stenosis. It was reported for the clinical usefulness of carotid endarterectomy in symptomatic patients by Wildy et al 6 Carotid endarterectomy was emphasized for diagnostic accuracy as primary surgical intervention for the treatment of severely stenosed À70z distal internal carotid artery stenosis by Shinner et al 23 In another histopathological study, carotid artery plaque features were compared in symptomatic and asymptomatic patients for gross ulceration, plaque rapture, brous cap thinning, cap foam cells, intra-plaquê brin and intra-plaque hemorrhage. These exhibited signiˆcant diŠerences 32-47z suggestive to normalize these four measures in the symptomatic group shown in Table 1 (personal communication with Dr. Virmani R).…”

Section: Introductionmentioning

confidence: 99%

MR Imaging in Carotid Artery Atherosclerosis Plaque Characterization

Sharma

2002

MRMS

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Aim: To evaluate the potential role of carotid artery atherosclerosis plaque magentic resonance (MR) microimaging as magnetic resonance imaging (MRI) marker, ex vivo MR images were acquired at optimized parameters on 9.4T Bruker animal imager for occluded tissue resected by carotid endarterectomy (CEA) and corresponding histopathological analysis was made.Methods and Materials: For imaging, CEA tissues of size 2-6 cm long and 0.5-1.5 cm wide, were transferred to 15 ml co-polymer laboratory culture tubes containing either 10z formalin in phosphate buŠered saline (PBS) or in 50z glycerol in PBS. Imaging protocol was set at TE＝30 ms, TR＝1.5 s, matrix size＝265×512, NEX＝128, slice thickness＝1 mm and in-plane resolution＝0.1 mm for total sample size 2.5 cm. Soon after imaging done, carotid artery tissues were cut into 5-mm segments and processed for histological section for successive 5-micrometer slices. To compare morphology of 5 mm thin CEA section with that of 1 mm MR slices, registration was obtained between histologic sections and MR slices. Contrast and magnetic resonance relaxation characteristics were analyzed.Results: Total carotid artery area computed by MR imaging was correlated with areas determined from histologic sections (r 2 ＝0.989, p＝0.0001). For the lumen area, the correlation between MR images and histologic area was (r 2 ＝0.942, p＝0.0001). Relaxation times and T 2 parametric images of diŠerent plaque components were determinant for contrast resolution. Scan parameters were optimized forˆbrous cap and atheroma. Scan parameters were characteristic for comparison at 1.5T and 9.4T MR imagers.Conclusion: The observed correlation validated MR microimaging to assess morphological features of carotid artery plaques and contrast resolution highlighted the potential of in vivo MR imaging as non-invasive MRI marker to monitor carotid artery plaque morphometry and plaque composition.

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“…To date, magnetic resonance (MR)-based studies of atherosclerotic tissue primarily have been based on spectroscopy or 2D imaging. [17][18][19][20][21][22][23] These techniques resolve tissue at a level of 1 to 2 mm in Ն1 direction, obscuring the submillimeter architecture of plaque by partial volume averaging.…”

mentioning

confidence: 99%

Structure of Plaque at Carotid Bifurcation: High-Resolution MRI With Histological Correlation

Coombs¹,

Rapp²,

Ursell³

et al. 2001

Stroke

106

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Background and Purpose-The composition of carotid atherosclerosis was visualized by using 3D MRI at high resolution with 200-m 3 voxels. Magnetic resonance signal characteristics were correlated with plaque components, including collagenous cap, necrotic core, and calcification, to define resolution and other requirements for future clinical carotid MRI. Methods-Twenty-one en bloc carotid endarterectomy specimens were imaged ex vivo by 3D gradient-echo MRI by using a 1.5-T clinical scanner with repetition time, echo time, and flip angle of 40 ms, 18 ms, and 20°, respectively. Plaques were placed in Gd-saline and imaged in a solenoid radiofrequency coil. For quantitative tissue-specific signal analysis, techniques were developed to match tissue sections analyzed by MRI and histology. Results-Three-dimensional imaging resolved complex morphological features not visualized by density-or T 2 -weighted 2D spin-echo imaging. The collagenous cap, necrotic core, and areas of focal calcification showed differing signal characteristics: mean contrast-to-noise ratio for cap versus underlying core was 20. The signal distributions for media and necrotic core overlapped but were resolvable in most specimens. The signal from thrombus was variable. Conclusions-En bloc specimens provide a useful model for studying plaque MRI. By use of isotropic submillimeter resolution, the collagenous cap and underlying necrotic core typically can be distinguished, and calcification can be identified. Thrombus displays a wide variation in signal intensity.

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Atherosclerosis of the carotid artery: Evaluation by magnetic resonance angiography

Cited by 22 publications

References 13 publications

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

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

MR Imaging in Carotid Artery Atherosclerosis Plaque Characterization

Structure of Plaque at Carotid Bifurcation: High-Resolution MRI With Histological Correlation

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