title: Carotid magnetization-prepared rapid acquisition with gradient-echo signal is associated with acute territorial cerebral ischemic events detected by diffusion-weighted MRI.
abstract: BACKGROUND
  Carotid intraplaque hemorrhage has been associated with symptomatic stroke and can be accurately detected with magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Currently, there are no studies analyzing carotid MPRAGE signal and territorial ischemic events defined by diffusion restriction in the acute setting. Our aim was to determine the association of carotid MPRAGE signal with acute territorial ischemic events using carotid MPRAGE and brain diffusion tensor imaging.
  
  
  RESULTS
  After the addition of the MPRAGE sequence to the neck MR angiographic protocol, 159 patients with suspected acute stroke were evaluated with both brain diffusion tensor imaging and carotid MPRAGE sequences over 2 years, providing 318 carotid artery and paired brain images for analysis. Forty-eight arteries were excluded due to extracarotid sources of brain ischemia and 4 were excluded due to carotid occlusion. Two hundred sixty-six arteries were eligible for data analysis. Carotid MPRAGE-positive signal was associated with an acute cerebral territorial ischemic event with a relative risk of 6.4 (P<0.001). The relative risk of a diffusion tensor imaging-positive territorial ischemic event with carotid MPRAGE-positive signal was increased in mild, moderate, and severe stenosis categories (10.3, P<0.001; 2.9, P=0.01; and 2.2, P=0.01, respectively).
  
  
  CONCLUSIONS
  In the workup of acute stroke, carotid MPRAGE-positive signal was associated with an increased risk of territorial cerebral ischemic events as detected objectively by brain diffusion tensor imaging. The relative risk of stroke was increased in all carotid stenosis categories but was most elevated in the mild stenosis category.
authors.affiliation: Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah School of Medicine, Salt Lake City, UT 84132-2140, USA. jmcnall76@gmail.com
authors.forename: J Scott
authors.initials: JS
authors.lastname: McNally
authors.forename: Seong-Eun
authors.initials: SE
authors.lastname: Kim
authors.forename: Hyo-Chun
authors.initials: HC
authors.lastname: Yoon
authors.forename: Laura K
authors.initials: LK
authors.lastname: Findeiss
authors.forename: John A
authors.initials: JA
authors.lastname: Roberts
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Nightingale
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Narra
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Parker
authors.forename: Gerald S
authors.initials: GS
authors.lastname: Treiman
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000175:diagnosis*; D002536:Cerebral Arteries / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D055815:Young Adult