Regional cerebral blood flow in peritumoral brain edema during dexamethasone treatment: a xenon-enhanced computed tomographic study.
OBJECTIVE
Regional cerebral flood flow (rCBF) in peritumoral brain edema is assumed to be decreased because of increased interstitial pressure. Impaired blood flow might lead to local hypoxia, altered metabolism, and disturbed ion homeostasis, thus causing neurological sequelae. Steroid treatment is thought to positively influence the sequelae of brain edema. We aimed to determine the rCBF in peritumoral edema in humans receiving dexamethasone treatment and the relationship of rCBF to global CBF.


METHODS
We measured rCBF in 11 patients with untreated anaplastic gliomas or glioblastomas that were World Health Organization Grade III or IV restricted to one hemisphere with significant peritumoral edema who were receiving a standard dose of dexamethasone. rCBF was determined using stable xenon-enhanced computed tomography in a stereotactic frame. Edema was defined both by means of actual histology (stereotactic biopsies) and by imaging criteria.


RESULTS
rCBF in peritumoral edema was decreased by 32% as compared with contralateral normal white matter. In each patient, this reduction was linearly related to blood flow in nonaffected white matter and cortex. The flow ratio in the different compartments was 1 (edema):1.5 (contralateral white matter):2.7 (contralateral cortex). Absolute perfusion values in contralateral cortex (means +/- standard deviations) (29.9+/-7.1 ml/100 g/min) and contralateral white matter (16.1+/-3.7 ml/100 g/min) were significantly decreased as well.


CONCLUSIONS
Our study demonstrated that rCBF in peritumoral brain edema during steroid treatment is still decreased and is in a range in which it may cause neurological sequelae. Also, global CBF was decreased in all patients.
Neurologische Universitätsklinik, Freiburg, Germany.
P F
PF
Behrens
C B
CB
Ostertag
P C
PC
Warnke
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001783:Blood Flow Velocity / Q000187:drug effects; D001921:Brain / Q000098:blood supply*; D001929:Brain Edema / Q000000981:diagnostic imaging / Q000188:drug therapy*; D002540:Cerebral Cortex / Q000098:blood supply; D003287:Contrast Media; D003907:Dexamethasone / Q000009:adverse effects / Q000627:therapeutic use*; D004292:Dominance, Cerebral / Q000187:drug effects; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000188:drug therapy*; D005910:Glioma / Q000000981:diagnostic imaging / Q000188:drug therapy*; D006801:Humans; D007427:Intracranial Pressure / Q000187:drug effects; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D015173:Supratentorial Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy*; D014057:Tomography, X-Ray Computed; D014978:Xenon
D000893:Anti-Inflammatory Agents; D003287:Contrast Media; D014978:Xenon; D003907:Dexamethasone