title: Global cerebral blood flow after CO2 inhalation in normal subjects and patients with panic disorder determined with [15O]water and PET.
abstract: OBJECTIVE
  To determine the effect of CO2 inhalation on global cerebral blood flow (gCBF) and pCO2-adjusted gCBF in normal subjects and panic disorder patients.
  
  
  METHODS
  Global cerebral blood flow was determined using quantitative [15O] water imaging in normal subjects (n = 12) and panic disorder patients (n = 14) after inhalations of medical grade air and of 35%/65% CO2/O2 mixture, a known inducer of panic. The gCBF was calculated as an area-weighted mean value. The pCO2 -adjusted gCBF values were calculated based on the formula of Reiman et al. [Am. J. Psychiatr. 143 (1986) 469]. Data were analyzed using repeated-measures ANOVA and regression analyses.
  
  
  RESULTS
  The pCO2 values did not differ statistically between normals and panic patients. Panic patients exhibited a decrease in gCBF and stable pCO2-adjusted gCBF values in comparisons of AIR and CO2 inhalations, whereas normals exhibited stable gCBF and increasing pCO2-adjusted gCBF values.
  
  
  CONCLUSIONS
  Patients with panic disorder, especially when symptomatic, exhibited an abnormal pattern in gCBF response to provocation.
authors.affiliation: Department of Radiology, PET Imaging Center, University of Iowa Hospitals and Clinics, Iowa City 52242, USA. laura-ponto@uiowa.edu
authors.forename: Laura L Boles
authors.initials: LL
authors.lastname: Ponto
authors.forename: Roger G
authors.initials: RG
authors.lastname: Kathol
authors.forename: Richard
authors.initials: R
authors.lastname: Kettelkamp
authors.forename: G Leonard
authors.initials: GL
authors.lastname: Watkins
authors.forename: John C W
authors.initials: JC
authors.lastname: Richmond
authors.forename: Jo
authors.initials: J
authors.lastname: Clark
authors.forename: Richard D
authors.initials: RD
authors.lastname: Hichwa
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002245:Carbon Dioxide / Q000008:administration & dosage*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010104:Oxygen Radioisotopes; D016584:Panic Disorder / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014867:Water
chemical_list: D010104:Oxygen Radioisotopes; D014867:Water; D002245:Carbon Dioxide