title: Hemodynamic Significance of Internal Carotid or Middle Cerebral Artery Stenosis Detected on Magnetic Resonance Angiography.
abstract: OBJECTIVE
  We evaluated hemodynamic significance of stenosis on magnetic resonance angiography (MRA) using acetazolamide perfusion single photon emission computed tomography (SPECT).
  
  
  METHODS
  Of 171 patients, stenosis in internal carotid artery (ICA) and middle cerebral artery (MCA) (ICA-MCA) on MRA and cerebrovascular reserve (CVR) of MCA territory on SPECT was measured using quantification and a 3-grade system. Stenosis and CVR grades were compared with each other, and their prognostic value for subsequent stroke was evaluated.
  
  
  RESULTS
  Of 342 ICA-MCA, 151 (44%) presented stenosis on MRA; grade 1 in 69 (20%) and grade 2 in 82 (24%) cases. Decreased CVR was observed in 9% of grade 0 stenosis, 25% of grade 1, and 35% of grade 2. The average CVR of grade 0 was significantly different from grade 1 (p<0.001) and grade 2 stenosis (p=0.007). In quantitative analysis, average CVR index was -0.56±7.91 in grade 0, -1.81±6.66 in grade 1 and -1.18±5.88 in grade 2 stenosis. Agreement between stenosis and CVR grades was fair in patients with lateralizing and non-lateralizing symptoms (κ=0.230 and 0.346). Of the factors tested, both MRA and CVR were not significant prognostic factors (p=0.104 and 0.988, respectively), whereas hypertension and renal disease were significant factors (p<0.05, respectively).
  
  
  CONCLUSIONS
  A considerable proportion of ICA-MCA stenosis detected on MRA does not cause CVR impairment despite a fair correlation between them. Thus, hemodynamic state needs to be assessed for evaluating significance of stenosis, particularly in asymptomatic patients.
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.|Department of Molecular Medicine and Biopharmaceutical Sciences, WCU Graduate School of Convergence Science and Technology, Seoul National University College of Medicine, Seoul, Korea.|Department of Nuclear Medicine, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hyo Jung
authors.initials: HJ
authors.lastname: Seo
authors.affiliation: Department of Nuclear Medicine, The Medical City, Pasig City, Philippines.
authors.forename: Jefferson R
authors.initials: JR
authors.lastname: Pagsisihan
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea. paengjc@snu.ac.kr.
authors.forename: Jin Chul
authors.initials: JC
authors.lastname: Paeng
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Seung Hong
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.|Department of Molecular Medicine and Biopharmaceutical Sciences, WCU Graduate School of Convergence Science and Technology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
mesh_terms: D000086:Acetazolamide; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D003251:Constriction, Pathologic; D004232:Diuretics; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007457:Iodine Radioisotopes; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D004232:Diuretics; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D000086:Acetazolamide
keywords: Magnetic resonance angiography; acetazolamide-challenged brain perfusion SPECT; cerebrovascular reserve; stenosis; stroke