Application of radionuclide cisternography in the selection of communicating hydrocephalus patients for shunt surgery

Sixteen patients with suspected CSF dynamics disturbances were investigated in order to correlate the clinical picture with ICG patterns and ICG and spinal infusion tests (SIT). Fourteen of them had manifested decreased intellectual ability, associated in 10 cases with abnormal gait and in 5 with urinary incontinence. In one patient gait disturbance was the only symptom and in the other one the only symptom was headache. CT criteria for hydrocephalus were fulfilled by 14 patients. The tracer used was 169Yb labelled DTPA (37 MBq). It was applied via the lumbar route and scans were performed at 3, 24, 48 and 72 hours post injection. In all hydrocephalus cases but one, ventricular reflux was found 24 hours after the tracer instillation. Eight had ventricular retention prolonged up to 48 hours or longer, and in 6 of them this was associated with delayed convexity flow. CSF absorption capacity was studied by means of SIT. A deficit was found in 4 patients who fulfilled criteria for hydrocephalus and these were subsequently shunted. Three of four shunted patients have improved. None of the unoperated cases has deteriorated as shown in follow-ups from 3 to 25 months. No relationship between SIT and ICG and between SIT and CT parameters was confirmed. However, a correlation was disclosed between the size of the ventricular system and the isotope clearance delay. It was concluded that an abnormal cisternography pattern more likely discloses CSF circulation abnormality than CSF absorption deficit. (author) 3 tabs., 34 refs