title: Assessment of Hemodynamic Compromise Using Computed Tomography Perfusion in Combination with123I-IMP Single-Photon Emission Computed Tomography without Acetazolamide Challenge Test.
abstract: OBJECTIVE
  The acetazolamide challenge test in conjunction with123I-IMP single-photon emission computed tomography (SPECT) is a known method of assessing cerebrovascular reserve capacity. In this study, we investigated whether CT perfusion in combination with resting state123I-IMP SPECT could be used instead of the acetazolamide challenge test to evaluate hemodynamic compromise in patients with atherosclerotic occlusive disease.
  
  
  METHODS
  Twenty consecutive patients with unilateral internal carotid artery or middle cerebral artery steno-occlusive disease were enrolled.123I-IMP SPECT was performed with and without the acetazolamide challenge test, and with CT perfusion. Cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) obtained by CT perfusion were compared with CBF and cerebrovascular reactivity (CVR) obtained by123I-IMP SPECT.
  
  
  RESULTS
  The asymmetry ratio of MTT as measured by CT perfusion showed a strong correlation with the CVR to acetazolamide as measured by123I-IMP SPECT (ρ = -.780, P <.001). Based on the CBF obtained through123I-IMP SPECT and the MTT obtained through CT perfusion, hemodynamic compromise was detected with high sensitivity (1.000) and specificity (.929), and a cutoff value of 30% was found to be suitable for the asymmetry ratio of MTT. MTT prolongation was significantly improved after revascularization surgery in hemodynamic compromise (P = .028).
  
  
  CONCLUSIONS
  MTT as measured by CT perfusion in combination with CBF as measured by resting state123I-IMP SPECT may be useful for evaluating hemodynamic compromise as an alternative to the acetazolamide challenge test.
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Atsumu
authors.initials: A
authors.lastname: Hashimoto
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan. Electronic address: tmikami@sapmed.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mikami
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Komatsu
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Shouhei
authors.initials: S
authors.lastname: Noshiro
authors.affiliation: Division of Radiology, Sapporo Medical University Hospital, Sapporo, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Hirano
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Wanibuchi
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mikuni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D020367:Iofetamine / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D010477:Perfusion; D012372:ROC Curve; D019275:Radiopharmaceuticals / Q000378:metabolism; D012189:Retrospective Studies; D013223:Statistics as Topic; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D020367:Iofetamine
keywords: Cerebrovascular reactivity; cerebral blood flow; cerebral blood volume; mean transit time