title: High signal intensity on T2-weighted magnetic resonance imaging and cerebral hemodynamic reserve in carotid occlusive disease.
abstract: OBJECTIVE
  The importance of MR imaging in carotid artery disease is unclear. We evaluated the sensitivity and specificity of the high signal intensity changes on MR images for diagnosis of hemodynamically compromised unilateral internal carotid artery disease.
  
  
  METHODS
  We evaluated the association of high signal intensities on T2-weighted MR images with changes in cerebral perfusion reserve measured using 99mTc-hexamethylpropyleneamine oxime single-photon emission CT and acetazolamide in 23 patients.
  
  
  RESULTS
  Eleven patients had a type I response (normal flow and normal perfusion reserve), 8 patients had a type II response (normal flow and decreased perfusion reserve), and 4 patients had a type III response (decreased flow and decreased perfusion reserve). High signal intensities in the centrum semiovale (11/12) and/or posterior periventricular white matter (6/12) were frequently seen in the hemodynamically compromised groups. Extensive high signal intensities were associated with severely impaired cerebral circulation. MR imaging had high sensitivity (0.92) and specificity (1.0) in predicting hemodynamically compromised patients when we used the presence of T2 high intensity in the centrum semiovale as a criterion.
  
  
  CONCLUSIONS
  The centrum semiovale T2 hyperintensities lateralized to the side of carotid occlusion are specific and sensitive for the presence and severity of hemodynamic compromise from carotid occlusive disease.
authors.affiliation: Department of Nuclear Medicine, Osaka National Hospital, Japan. yoshisk@onh.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Isaka
authors.forename: K
authors.initials: K
authors.lastname: Nagano
authors.forename: M
authors.initials: M
authors.lastname: Narita
authors.forename: K
authors.initials: K
authors.lastname: Ashida
authors.forename: M
authors.initials: M
authors.lastname: Imaizumi
mesh_terms: D000086:Acetazolamide; D000368:Aged; D002545:Brain Ischemia / Q000209:etiology; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000209:etiology; D002546:Ischemic Attack, Transient / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D000086:Acetazolamide