title: Localization of Coronary High-Intensity Signals on T1-Weighted MR Imaging: Relation to Plaque Morphology and Clinical Severity of Angina Pectoris.
abstract: OBJECTIVE
  This study sought to investigate the relationship between localization of high-intensity signals (HISs) on T1-weighted imaging (T1WI) with the noncontrast magnetic resonance technique and plaque morphology detected on optical coherence tomography, and the clinical severity of angina pectoris.
  
  
  BACKGROUND
  Since the introduction of the T1WI noncontrast magnetic resonance technique for plaque imaging, some groups have reported that HISs in the coronary artery on T1WI are associated with a vulnerable morphology and future cardiac events. However, the association between the localization of HISs, such as coronary intrawall or intraluminal, and plaque morphology has not been investigated.
  
  
  METHODS
  One hundred lesions with either stable or unstable angina were included and divided into 3 groups according to the following criteria using T1WI. First, the plaques with the ratio between the signal intensities of coronary plaque and cardiac muscle ≤1.0 were classified as non-HISs (n = 39). Then, HISs with the ratio between the signal intensities of coronary plaque and cardiac muscle >1.0 were classified into 2 types by using cross-sectional T1WI. Those localized within the coronary wall when the lumen was identified were defined as intrawall HISs (n = 37), whereas those occupying the lumen when the lumen was not, or even if only partly, identified, were defined as intraluminal HISs (n = 24).
  
  
  RESULTS
  Multivariate analysis revealed that intrawall HISs were associated with macrophage accumulation and the absence of calcification assessed by using optical coherence tomography. In contrast, thrombus and intimal vasculature were independent factors associated with intraluminal HISs. Furthermore, 50% of patients with intraluminal HISs experienced rest angina, such as Braunwald class II or III.
  
  
  CONCLUSIONS
  This study shows that intrawall and intraluminal HISs on T1WI in patients with angina are related to the different types of vulnerable plaque morphology and the clinical severity.
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan. Electronic address: ehara@med.osaka-cu.ac.jp.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Ehara
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Mikumo
authors.initials: M
authors.lastname: Sakaguchi
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Otsuka
authors.affiliation: Nishinomiya Watanabe Cardiovascular Center, Hyogo, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Yoshikawa
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kenei
authors.initials: K
authors.lastname: Shimada
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis / Q000209:etiology*; D016009:Chi-Square Distribution; D003324:Coronary Artery Disease / Q000150:complications / Q000473:pathology*; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence
keywords: angina pectoris; atherosclerosis; intraplaque hemorrhage; magnetic resonance imaging; optical coherence tomography; thrombosis