Global cerebral blood flow after CO2 inhalation in normal subjects and patients with panic disorder determined with [15O]water and PET.
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.
Ponto
Laura L Boles
LL
Department of Radiology, PET Imaging Center, University of Iowa Hospitals and Clinics, Iowa City 52242, USA. laura-ponto@uiowa.edu
Kathol
Roger G
RG
Kettelkamp
Richard
R
Watkins
G Leonard
GL
Richmond
John C W
JC
Clark
Jo
J
Hichwa
Richard D
RD
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
D010104:Oxygen Radioisotopes; D014867:Water; D002245:Carbon Dioxide