title: Acetazolamide challenge and technetium-99m-ECD versus iodine-123-IMP SPECT in chronic occlusive cerebrovascular disease.
abstract: We compared the acetazolamide challenge test using 99mTc-ECD SPECT and 123I-IMP SPECT images in patients with chronic occlusive cerebrovascular disease. We also evaluated the usefulness of linearization correction for acetazolamide challenge test of 99mTc-ECD SPECT.
  
  
  METHODS
  Twenty patients with unilateral chronic occlusive cerebrovascular disease (10 patients had middle cerebral arterial lesion and 10 had internal carotid lesion) were included in the study. Split-dose (a dose fractioning was 1:2), and sequential SPECT technique was used for 99mTc-ECD SPECT studies while only acetazolamide challenge test studies for 123I-IMP SPECT were performed. Permeability surface area product model (PS model) and back-diffusion model (Lassen's correction) were used for linearization correction of acetazolamide challenge with 99mTc-ECD SPECT.
  
  
  RESULTS
  Six of 16 patients with reduced vasodilatory capacity in 123I-IMP SPECT were underestimated by 99mTc-ECD SPECT acetazolamide challenge test. Relative ECD uptake normalized by cerebellar uptake compared with IMP uptake showed a nonlinear relationship, indicating relatively less uptake in high flow range. The underestimations of limited vasodilatory capacity observed in 99mTc-ECD SPECT without linearization correction was modified by linearization algorithm. However, the effect of correction based on PS model was superior than that of Lassen's correction. The corrected 99mTc-ECD uptake ratio, based on PS model, and IMP uptake ratio demonstrated a better linear relationship than that of Lassen's correction.
  
  
  CONCLUSIONS
  Technetium-99m ECD SPECT corrected based on the PS model is a better method of linearization for evaluating cerebrovascular reserve using acetazolamide challenge.
authors.affiliation: Department of Radiology, Junwa Memorial Hospital, Komatsu, Miyazaki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Yano
authors.forename: S
authors.initials: S
authors.lastname: Nakano
authors.forename: S
authors.initials: S
authors.lastname: Jinnouchi
authors.forename: S
authors.initials: S
authors.lastname: Nagamachi
authors.forename: L I
authors.initials: LI
authors.lastname: Flores
authors.forename: H
authors.initials: H
authors.lastname: Nakahara
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology*; D000368:Aged; D000369:Aged, 80 and over; D000662:Amphetamines; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002908:Chronic Disease; D003545:Cysteine / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D020367:Iofetamine; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000662:Amphetamines; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D020367:Iofetamine; C059659:technetium Tc 99m bicisate; D003545:Cysteine; D000086:Acetazolamide