Utility of high resolution MR imaging to assess carotid plaque morphology: A comparison of acute symptomatic, recently symptomatic and asymptomatic patients with carotid artery disease

Sadat, Umar; Weerakkody, Ruwan; Bowden, David J.; Young, Victoria; Graves, Martin J.; Li, Zhi Yong; Tang, Tjun Yip; Gaunt, Michael E.; Hayes, Paul D.; Gillard, Jonathan H.

doi:10.1016/j.atherosclerosis.2009.05.002

Cited by 73 publications

(72 citation statements)

References 29 publications

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“…31 The prevalence of PH in the present patients was 62%, which is in accordance with the aforementioned study and with our previous report. 19 In the present study FEA was used for the biomechanical stress simulations. We have used this method extensively in the past to assess features of plaque vulnerability and compare different patient groups.…”

Section: Discussionmentioning

confidence: 99%

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Utility of Magnetic Resonance Imaging-Based Finite Element Analysis for the Biomechanical Stress Analysis of Hemorrhagic and Non-Hemorrhagic Carotid Plaques

Sadat

Zhang

Young

et al. 2011

Circ J

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Background: Biomechanical stress analysis has been used for plaque vulnerability assessment. The presence of plaque hemorrhage (PH) is a feature of plaque vulnerability and is associated with thromboembolic ischemic events. The purpose of the present study was to use finite element analysis (FEA) to compare the stress profiles of hemorrhagic and non-hemorrhagic profiles. Methods and Results:Forty-five consecutive patients who had suffered a cerebrovascular ischemic event with an underlying carotid artery disease underwent high-resolution magnetic resonance imaging (MRI) of their symptomatic carotid artery in a 1.5-T MRI system. Axial images were manually segmented for various plaque components and used for FEA. Maximum critical stress (M-CstressSL) for each slice was determined. Within a plaque, the maximum M-CstressSL for each slice of a plaque was selected to represent the maximum critical stress of that plaque (M-CstressPL) and used to compare hemorrhagic and non-hemorrhagic plaques. A total of 62% of plaques had hemorrhage. It was observed that plaques with hemorrhage had significantly higher stress (M-CstressPL) than plaques without PH ( Conclusions: Hemorrhagic plaques have higher biomechanical stresses than non-hemorrhagic plaques. MRIbased FEA seems to have the potential to assess plaque vulnerability. (Circ J 2011; 75: 884 - 889)

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Section: Discussionmentioning

confidence: 99%

“…using previously published criteria. 18, 19 Briefly, LRNC appears to be hyperintense on T1-and PD-weighted images, and hypointense on STIR and T2-weighted images. Fibrous tissue appears isointense -hypointense on T1-and PD-weighted images, and hyperintense on STIR and T2-weighted images.…”

Section: Mri Analysismentioning

confidence: 99%

Utility of Magnetic Resonance Imaging-Based Finite Element Analysis for the Biomechanical Stress Analysis of Hemorrhagic and Non-Hemorrhagic Carotid Plaques

Sadat

Zhang

Young

et al. 2011

Circ J

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“…Carotid stenosis was assessed with ultrasonography, as recommended by the North American Symptomatic Carotid Endarterectomy Trial collaborators [7]. We defined patients as symptomatic if they experienced a transient ischemic attack (TIA) or cerebral infarction caused by carotid stenosis within 180 days; patients were defined as asymptomatic if they were either truly asymptomatic or had been asymptomatic for >180 days according to previous reports [8,9]. In the symptomatic patients, there were no atrial flutter, atrial fibrillation or lacunar infarctions.…”

Section: Methodsmentioning

confidence: 99%

“…Symptomatic plaques were divided into an early symptomatic group and a late symptomatic group. According to the previous report, early symptomatic plaques were defined as plaques that had tissue characterization within 3 days of the onset of TIA or cerebral infarction caused by carotid stenosis (1 day: n = 5, 2 days: n = 9, 3 days: n = 11) [9], whereas late symptomatic plaques were treated by statins and/or cilostazol for 30–180 days after TIA or CI onset caused by carotid stenosis and allowed to stabilize before tissue characterization (30–59 days: n = 5, 60–89 days: n = 6, 90–119 days: n = 3, 150–180 days: n = 6) [9]. All the patients in the late symptomatic group were transferred to our hospital from affiliate hospitals where carotid artery stenting or carotid endarterectomy could not be performed.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Symptomatic Carotid Plaques by Tissue Characterization Using Integrated Backscatter Ultrasound and Magnetic Resonance Imaging

Yamada¹,

Kawasaki²,

Yoshimura³

et al. 2011

Cerebrovasc Dis

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Background: Unstable carotid plaques that consist of large lipid pool and intraplaque hemorrhage are more likely to cause cerebral infarction. We previously developed an integrated backscatter (IBS) ultrasound color-coded mapping method to evaluate the tissue characteristics of plaques. The purpose of this study was to determine whether 3-dimensional IBS color-coded mapping and signal intensity ratio (SIR) from magnetic resonance imaging (MRI) could distinguish the early symptomatic plaques from late symptomatic plaques. Methods: We performed quantitative tissue characterization of carotid plaques measuring IBS values and the SIR from T₁-weighted MRI images in 95 carotid plaques (>50% stenosis) in 95 patients (45 symptomatic, 50 asymptomatic). Results: The percent unstable component volume (UCV) that consisted of lipid pool and intraplaque hemorrhage and the SIR of symptomatic carotid plaques were higher than those of asymptomatic plaques (57.8 ± 25.1 vs. 46.8 ± 25.1%, p = 0.036; 1.31 ± 0.25 vs. 1.21 ± 0.26, p = 0.047). In patients that were imaged within 3 days of symptom onset, the %UCV and SIR were significantly higher than the values in patients that were imaged 30–180 days after symptom onset (73.1 ± 18.4 vs. 38.7 ± 18.4%, p < 0.001; 1.38 ± 0.22 vs. 1.22 ± 0.26, p = 0.031). From the analysis of receiver operating characteristic curves, a %UCV of 50% (measured by IBS) and an SIR of 1.25 (measured by MRI) were the most optimal cutoff values for identifying early symptomatic plaques. Conclusions: Noninvasive quantitative tissue characterization of atherosclerotic lesions in carotid arteries using IBS ultrasound and MRI is useful to distinguish early symptomatic plaques from late symptomatic plaques.

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“…18 Briefly speaking, patients underwent high resolution MRI of their carotid arteries in a 1.5 Tesla MRI system (Signa HDx GE Healthcare, Waukesha, WI, USA) with a 4-channel phased-array neck coil (PACC, Machnet BV, Elde, The Netherlands). Movement artefact was minimized using a dedicated vacuum-based head restraint system (VAC-LOK Cushion, Oncology Systems Limited, UK) to fix the head and neck in a comfortable position and allow close apposition of the surface coils.…”

Section: High Resolution Multi-sequence Mrimentioning

confidence: 99%

Normalized Wall Index Specific and MRI-Based Stress Analysis of Atherosclerotic Carotid Plaques - A Study Comparing Acutely Symptomatic and Asymptomatic Patients -

Zhu

Zhang

Sadat

et al. 2010

Circ J

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Background: Biomechanical stresses play an important role in determining plaque stability. Quantification of these simulated stresses can be potentially used to assess plaque vulnerability and differentiate different patient groups.Methods and Results: 54 asymptomatic and 45 acutely symptomatic patients underwent in vivo multicontrast magnetic resonance imaging (MRI) of the carotid arteries. Plaque geometry used for finite element analysis was derived from in vivo MRI at the sites of maximum and minimum plaque burden. In total, 198 slices were used for the computational simulations. A pre-shrink technique was used to refine the simulation. Maximum principle stress at the vulnerable plaque sites (ie, critical stress) was extracted for the selected slices and a comparison was performed between the 2 groups. Critical stress in the slice with maximum plaque burden is significantly higher in acutely symptomatic patients as compared to asymptomatic patients (median, inter quartile range: 198.0 kPa (119.8-359.0 kPa) vs 138.4 kPa (83.8-242.6 kPa), P=0.04). No significant difference was found in the slice with minimum plaque burden between the 2 groups .7 kPa) vs 182.4 kPa (117.2-310.6 kPa), P=0.82). Conclusions:Acutely symptomatic carotid plaques have significantly high biomechanical stresses than asymptomatic plaques. This might be potentially useful for establishing a biomechanical risk stratification criteria based on plaque burden in future studies. (Circ J 2010; 74: 2360 - 2364

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Utility of high resolution MR imaging to assess carotid plaque morphology: A comparison of acute symptomatic, recently symptomatic and asymptomatic patients with carotid artery disease

Cited by 73 publications

References 29 publications

Utility of Magnetic Resonance Imaging-Based Finite Element Analysis for the Biomechanical Stress Analysis of Hemorrhagic and Non-Hemorrhagic Carotid Plaques

Utility of Magnetic Resonance Imaging-Based Finite Element Analysis for the Biomechanical Stress Analysis of Hemorrhagic and Non-Hemorrhagic Carotid Plaques

Evaluation of Symptomatic Carotid Plaques by Tissue Characterization Using Integrated Backscatter Ultrasound and Magnetic Resonance Imaging

Normalized Wall Index Specific and MRI-Based Stress Analysis of Atherosclerotic Carotid Plaques - A Study Comparing Acutely Symptomatic and Asymptomatic Patients -

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