title: Carotid artery plaque assessment using quantitative expansive remodeling evaluation and MRI plaque signal intensity.
abstract: OBJECTIVE
  Plaque characteristics and morphology are important indicators of plaque vulnerability. MRI-detected intraplaque hemorrhage has a great effect on plaque vulnerability. Expansive remodeling, which has been considered compensatory enlargement of the arterial wall in the progression of atherosclerosis, is one of the criteria of vulnerable plaque in the coronary circulation. The purpose of this study was risk stratification of carotid artery plaque through the evaluation of quantitative expansive remodeling and MRI plaque signal intensity.
  
  
  METHODS
  Both preoperative carotid artery T1-weighted axial and long-axis MR images of 70 patients who underwent carotid endarterectomy (CEA) or carotid artery stenting (CAS) were studied. The expansive remodeling ratio (ERR) was calculated from the ratio of the linear diameter of the artery at the thickest segment of the plaque to the diameter of the artery on the long-axis image. Relative plaque signal intensity (rSI) was also calculated from the axial image, and the patients were grouped as follows: Group A = rSI ≥ 1.40 and ERR ≥ 1.66; Group B = rSI< 1.40 and ERR ≥ 1.66; Group C = rSI ≥ 1.40 and ERR < 1.66; and Group D = rSI < 1.40 and ERR < 1.66. Ischemic events within 6 months were retrospectively evaluated in each group.
  
  
  RESULTS
  Of the 70 patients, 17 (74%) in Group A, 6 (43%) in Group B, 7 (44%) in Group C, and 6 (35%) in Group D had ischemic events. Ischemic events were significantly more common in Group A than in Group D (p = 0.01).
  
  
  CONCLUSIONS
  In the present series of patients with carotid artery stenosis scheduled for CEA or CAS, patients with plaque with a high degree of expansion of the vessel and T1 high signal intensity were at higher risk of ischemic events. The combined assessment of plaque characterization with MRI and morphological evaluation using ERR might be useful in risk stratification for carotid lesions, which should be validated by a prospective, randomized study of asymptomatic patients.
authors.affiliation: Department of Neurosurgery, Kurashiki Central Hospital, Okayama; and.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kurosaki
authors.affiliation: Department of Neurosurgery, Kyoto University School of Medicine, Kyoto, Japan.
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Neurosurgery, Kyoto University School of Medicine, Kyoto, Japan.
authors.forename: Ryu
authors.initials: R
authors.lastname: Fukumitsu
authors.affiliation: Department of Neurosurgery, Kurashiki Central Hospital, Okayama; and.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Sadamasa
authors.affiliation: Department of Neurosurgery, Kurashiki Central Hospital, Okayama; and.
authors.forename: Akira
authors.initials: A
authors.lastname: Handa
authors.affiliation: Department of Neurosurgery, Kurashiki Central Hospital, Okayama; and.
authors.forename: Masaki
authors.initials: M
authors.lastname: Chin
authors.affiliation: Department of Neurosurgery, Kurashiki Central Hospital, Okayama; and.
authors.forename: Sen
authors.initials: S
authors.lastname: Yamagata
mesh_terms: D000368:Aged; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D058226:Plaque, Atherosclerotic / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D012189:Retrospective Studies; D018570:Risk Assessment; D015607:Stents; D066253:Vascular Remodeling
keywords: BB = black blood; CAS = carotid artery stenting; CE = contrast enhanced; CEA = carotid endarterectomy; ERR = expansive remodeling ratio; ICA = internal carotid artery; IPH = intraplaque hemorrhage; VD = vessel diameter; carotid artery MRI; carotid artery disease; expansive remodeling; intraplaque hemorrhage; rSI = relative plaque signal intensity; risk stratification; vascular disorders