Clinical study of cerebrospinal fluid dynamics using 111In-DTPA SPECT in patients with subarachnoid hemorrhage.

The ventricle-to-background ratio and clearance rate constant measured by indium-111 diethylenetriaminepenta-acetic acid single photon emission computed tomography ((111)In-DTPA SPECT) were evaluated for predicting hydrocephalus in 16 patients at 2 to 3 weeks after onset of subarachnoid hemorrhage. The activity in the lateral ventricles, basal cistern, and hemispheric convexities was measured at 6, 24, and 48 hours after lumbar injection of radionuclide. In the follow-up study, eight patients developed hydrocephalus, and required ventriculoperitoneal shunting. Radioactivity measured in the hemispheric convexity did not reach peak activity within 48 hours. The clearance rate measured by applying the mono-exponential equation failed to show delayed clearance of radionuclide in hydrocephalus. The ratio between the ventricle and basal cistern measured at 6 hours postinjection was the best predictor of hydrocephalus (F(1, 30) = 42.84, p < 0.0001). These results suggest that a single (111)In-DTPA SPECT scan may be sufficient to identify patients at risk of developing hydrocephalus.