title: The value of acetazolamide single photon emission computed tomography scans in the preoperative evaluation of asymptomatic critical carotid stenosis.
abstract: OBJECTIVE
  Acetazolamide (ACZ)-enhanced single photon emission computed tomography (SPECT) scans can assess both cerebral perfusion and vascular reactivity. Patients with asymptomatic critical carotid artery stenosis were evaluated for cerebral vascular reactivity to determine the effect of extracranial occlusive disease and the effect of carotid endarterectomy (CEA) on intracerebral reactivity.
  
  
  METHODS
  In 44 patients with asymptomatic critical carotid artery stenosis, cerebral perfusion and vascular reactivity were assessed before CEA with resting and ACZ-enhanced SPECT scans. All patients had a 70% or greater ipsilateral internal carotid artery stenosis. Preoperative ACZ-enhanced SPECT scans were obtained, usually 5 days before CEA. Postoperative ACZ-enhanced SPECT scans were obtained in 30 patients.
  
  
  RESULTS
  Preoperative SPECT scans were asymmetric, revealing focal (n = 19) or global (n = 15) decreased reactivity in 34 patients (77%). Ten patients had symmetric or normal reactivity. After CEA, 23 patients demonstrated an improvement in reactivity ipsilateral to the side of surgery. The remaining seven patients failed to improve after surgery.
  
  
  CONCLUSIONS
  Although all patients had a high-grade internal carotid stenosis, nearly a quarter of the patients had excellent intracerebral collateral flow. Only 71% of patients demonstrated improved intracerebral vasoreactivity after CEA. The lack of improvement in the other patients may have resulted from intracerebral pathology or lack of improvement in the extracranial carotid hemodynamics.
authors.affiliation: Department of Surgery, Indiana University Medical Center, Richard L. Roudebush Veteran's Administration Hospital, Indianapolis 46202, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Cikrit
authors.forename: M C
authors.initials: MC
authors.lastname: Dalsing
authors.forename: S G
authors.initials: SG
authors.lastname: Lalka
authors.forename: R W
authors.initials: RW
authors.lastname: Burt
authors.forename: A P
authors.initials: AP
authors.lastname: Sawchuk
authors.forename: B A
authors.initials: BA
authors.lastname: Solooki
mesh_terms: D000086:Acetazolamide; D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000086:Acetazolamide