Pre and postoperative assessment of regional cerebral blood flow in hydrocephalus by 99mTc-hexamethyl-propylenamine oxime SPECT

Cerebrovascular changes resulting from hydrocephalus still remain to be investigated. It has been suggested that hydrocephalus distorts the large feeding arteries and that the collapse of capillaries results in decreased cerebral blood flow. This clinical study was designed to evaluate the effect of shunting on regional cerebral blood flow in patients with obstructive hydrocephalus of varying duration. Technetium-99m hexamethyl propyleamine oxime (99mTc-HMPAO) was used to measure the cerebral perfusion, semiquantitatively, since the pattern of its distribution in brain is somewhat similar to that of regional cerebral blood flow (rCBF), and the pre and postoperative semiquantitative rCBF values of each lobe were calculated. Fifteen patients (8 F, 7 M) underwent both CT and single photon emission tomography (SPECT) using 99mTc-HMPAO examination before and 1 week after shunting. Mean percentage of all lobes were calculated by subtracting the preoperative mean rCBF of all lobes from the corresponding postoperative values. The patients were classified into 3 groups according to the mean percentage of all lobes. Group A: showed a marked increase in mean cortical blood flow (+ 16.00 +/- 2.9%), group B: a moderate increase (11.27 +/- 4.8%), and in group C: there was the least improvement in mean cortical blood flow (+ 1.17 +/- 2.7%). The mean duration of hydrocephalus of group A, group B and group C was 5 +/- 0.5 weeks, 8 +/- 1 weeks and more than 12 weeks, respectively. Psychological testing and clinical observation of the daily activities of the patients postoperatively showed some correlation with increased rCBF and clinical improvement.(ABSTRACT TRUNCATED AT 250 WORDS)