title: Prediction of cerebral hyperperfusion after carotid endarterectomy using middle cerebral artery signal intensity in preoperative single-slab 3-dimensional time-of-flight magnetic resonance angiography.
abstract: OBJECTIVE
  Cerebral hyperperfusion after carotid endarterectomy (CEA) occurs in patients with preoperative impairments in cerebral hemodynamics. Signal intensity of the middle cerebral artery (MCA) on single-slab 3-dimensional time-of-flight magnetic resonance angiography (MRA) can assess hemodynamic impairment in the cerebral hemisphere. The purpose of the present study was to determine whether the signal intensity of the MCA on preoperative MRA could identify patients at risk for cerebral hyperperfusion after CEA.
  
  
  METHODS
  The signal intensity of the MCA ipsilateral to CEA on preoperative MRA was graded according to the ability to visualize the MCA in 81 patients with ipsilateral internal carotid artery stenosis (>or=70%). Cerebral blood flow was also quantified using single-photon emission computed tomography before and immediately after CEA and on the third postoperative day.
  
  
  RESULTS
  Cerebral hyperperfusion immediately after CEA (cerebral blood flow increase >or=100% compared with preoperative values) was observed in 10 patients. Multivariate analysis revealed that only reduced signal intensity of the MCA was significantly associated with the development of postoperative cerebral hyperperfusion (95% confidence interval, 1.015-1.401; P = 0.0319). When the reduced signal intensity of the MCA on MRA was defined as an impairment in cerebral hemodynamics, MRA grading resulted in 100% sensitivity and 63% specificity, with a 28% positive predictive value and a 100% negative predictive value for the development of post-CEA hyperperfusion. Hyperperfusion syndrome developed on the fourth and sixth postoperative days in 2 of the 10 patients who exhibited hyperperfusion immediately after CEA.
  
  
  CONCLUSIONS
  Signal intensity of the MCA, as assessed by this simple MRA method, may identify patients at risk for post-CEA cerebral hyperperfusion.
authors.affiliation: Department of Neurosurgery, Iwate Medical University, Morioka, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kuroda
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Ryonoshin
authors.initials: R
authors.lastname: Hirooka
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Shunro
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Kohei
authors.initials: K
authors.lastname: Chida
authors.forename: Daiya
authors.initials: D
authors.lastname: Ishigaki
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Otawara
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000601:surgery; D002560:Cerebrovascular Circulation; D004185:Disability Evaluation; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007291:Inosine Monophosphate; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011300:Preoperative Care; D012039:Regional Blood Flow / Q000502:physiology; D012189:Retrospective Studies; D012307:Risk Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D007291:Inosine Monophosphate