Radioisotope ventriculography for functional evaluation of the Ommaya Reservoir (author's transl)]

Thirty nine patients with diagnosis of meningeal leukemia, meningeal lymphoma and leukemia having high risk of meningeal involvement were treated with intraventricular administration of chemotherapeutic drugs via Ommaya reservoir. In all of those patients, radioisotope ventriculography was always performed with ytterbium-169 diethyltriamine pentaacetic acid (169Yb-DTPA) at 1 week after placement of the Ommaya reservoir. In the patients who had normal cerebrospinal (CSF) flow, majority of the radioactivity injected moved to cisterna magna and basal cistern at 4 hours after injection and to subarachnoid space of the cortical surface at 24 hours. Two cases of ventricular catheter occlusion were diagnosed by this method. Two cases of catheter tip misplacement were suspected with computed tomography and confirmed with radioisotope ventriculography. One of the misplacement cases developed focal leukoencephalopathy possibly due to high concentration of methotrexate (MTX) in the brain adjacent to the ventricular cathter. Two cases showed delayed CSF circulation, and the doses of MTX were decreased to be half of the ordinary dose (12 mg/M2 once a week) during initial phase of the treatment. The dose was increased after successful treatment of meningeal dissemination and restoration of the normal CSF flow. Radioisotope ventriculography might be quite useful for detection of the flow of materials placed into Ommaya reservoir. Routine use of this procedure may be helpful to prevent reservoir- and drug-related complications.