Measurement of cerebrovascular flow reserve in pediatric patients with sickle cell disease.
OBJECTIVE
To report a method for determining absolute percentage change in cerebral blood flow (measurement of cerebrovascular reserve) before and after acetylazolamide (Diamox) administration in children with sickle cell anemia.


METHODS
Thirty-six symptomatic sickle cell disease patients (48 studies) were evaluated. After the injection of either Tc-99m bicisate ethyl cysteinate dimer (ECD) or hexamethyl propylene amine oxime (HMPAO), both whole body scans (with geometric mean correction) and single photon emission computed tomography (CT) were performed pre- and post-Diamox administration with calculation of percentage brain uptake on the whole body images for both examinations and determination of cerebrovascular reserve (percentage change in brain uptake post-Diamox). Evaluation for regional cerebral perfusion change was also performed.


RESULTS
The cerebrovascular reserve measurement was 17.6% +/- 43.5% (mean +/- 1 SD). Thirty-three of 48 studies (69%) showed an abnormal cerebrovascular reserve, while only 6 of 48 studies (12.5%) showed Diamox-induced regional perfusion changes in the brain. No statistically significant relationship was found between the occurrence of a regional perfusion abnormality versus loss of cerebrovascular reserve (P = 0.75, Fisher exact test), suggesting that these are independent variables. The cerebrovascular reserve was reproducible, with an average standard deviation of +/-0.54%.


CONCLUSIONS
A new, simple method for calculation of cerebrovascular reserve is presented; this method is reproducible and appears to be an independent variable in the evaluation of cerebrovascular status in sickle cell anemia patients. It should allow further characterization of this complex patient population, and possibly assist in detection of patients at risk for developing "silent" or overt stroke.
Kedar
Amos
A
Department of Pediatrics, Division of Pediatric Hematology/Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0296, USA. kedara@peds.ufl.edu
Drane
Walter E
WE
Shaeffer
Douglas
D
Nicole
Michael
M
Adams
Caroline
C
D000086:Acetazolamide / Q000008:administration & dosage*; D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D000927:Anticonvulsants / Q000008:administration & dosage*; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D002648:Child; D003545:Cysteine / Q000008:administration & dosage / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D008297:Male; D015609:Organotechnetium Compounds / Q000008:administration & dosage; D010091:Oximes / Q000008:administration & dosage; D011859:Radiography; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology; D015899:Tomography, Emission-Computed, Single-Photon
D000927:Anticonvulsants; D015609:Organotechnetium Compounds; D010091:Oximes; D019275:Radiopharmaceuticals; C068296:hexamethylpropyleneamine oxime; C059659:technetium Tc 99m bicisate; D003545:Cysteine; D000086:Acetazolamide