Regional cerebral blood flow in normal pressure hydrocephalus.
Regional cerebral blood flow (rcbf) was studied preoperatively and at 2 and 6 months postoperatively in 22 normal pressure hydrocephalus patients using xenon-133 inhalation and single photon emission computed tomography. Sixteen of the 22 patients improved (improved group) and six did not (unimproved group). The following comparisons were made: (1) preoperative rcbf in the improved group, to 14 normal elderly volunteers and to that in 59 SDAT (senile dementia of the Alzheimer type) patients; (2) preoperative rcbf in the improved and unimproved groups to determine if rcbf could predict surgical outcome; (3) pre- to postoperative rcbf in the improved group to see if increased cbf accounted for clinical improvement. The findings were: (1) preoperative rcbf in the improved group was lower than that in normal controls but was the same as that in SDAT; however, the ratios of rcbf values in anterior and posterior brain regions were significantly different between improved group and SDAT (p = 0.02); (2) an anterior/posterior ratio of 1.05 correctly classified surgical outcome in 19/22 patients; five of six in the unimproved group were above this cut off while 14/16 in the improved group were below; (3) in the improved group rcbf increased at 2 but not at 6 months after surgery without a corresponding reduction of clinical signs, supporting the notion that increase in cbf probably does not account for clinical improvement in normal pressure hydrocephalus.
D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology*; D006850:Hydrocephalus, Normal Pressure / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D012016:Reference Values; D014055:Tomography, Emission-Computed; D014980:Xenon Radioisotopes
D014980:Xenon Radioisotopes