title: Postoperative evaluation of changes in extracranial-intracranial bypass graft using superficial temporal artery duplex ultrasonography.
abstract: OBJECTIVE
  Extracranial-intracranial (ECIC) bypass grafts have been assessed postoperatively by various neuroradiologic techniques. The aim of this prospective study was to evaluate postoperative changes in ECIC bypass graft by using superficial temporal artery duplex ultrasonography (STDU). Furthermore, this study assessed the ability of STDU to predict cerebrovascular reserve capacity (CVR).
  
  
  METHODS
  Forty-five consecutive patients who underwent ECIC bypass procedure for atherosclerotic internal carotid artery occlusion were enrolled in this prospective study. All patients underwent single-photon emission CT and STDU preoperatively, 14 days after, 3 months after, 1 year after, and 2 years after ECIC bypass.
  
  
  RESULTS
  The diameter and flow velocities of the ipsilateral superficial temporal artery (STA), and regional cerebral blood flow (rCBF) showed increase during the first 2 weeks and then remained stable, whereas CVR showed a constant improvement up to 2 years after surgery. The STA diameter and mean STA flow velocity correlated significantly with CVR at 1 year after surgery (r2 = 0.1232 and r2 = 0.08716, respectively; P < .05). A cutoff value of 1.8 mm STA diameter was determined as the most reliable value to predict CVR greater than 10% at 1 year after surgery. The positive predictive value was calculated as 96.6%, the negative predictive value as 43.8%, the sensitivity as 75.7%, the specificity as 87.5%, and the likelihood ratio as 6.056.
  
  
  CONCLUSIONS
  ECIC bypass grafts can be assessed postoperatively in a noninvasive fashion with STDU. This technique provides information regarding patency as well as quantitative assessment of bypass function. Moreover, STDU is useful to predict CVR improvement.
authors.affiliation: Department of Neurosurgery, Cerebrovascular Center and Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan. nakamizo@ns.med.kyushu-u.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Nakamizo
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Kikkawa
authors.forename: K
authors.initials: K
authors.lastname: Uda
authors.forename: Y
authors.initials: Y
authors.lastname: Hirata
authors.forename: K
authors.initials: K
authors.lastname: Okamura
authors.forename: M
authors.initials: M
authors.lastname: Yasaka
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
mesh_terms: D000368:Aged; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D002548:Cerebral Revascularization / Q000379:methods*; D004453:Echoencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011379:Prognosis; D013699:Temporal Arteries / Q000000981:diagnostic imaging* / Q000601:surgery; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods*