ONE OF the most common problems in the management of patients with hydrocephalus and persistent subdural effusions is the evaluation of the shunt system to determine its patency.
The classical method of determining whether or not a shunt system is patent is to utilize the simple digital or manual pumping technique which at times may not be reliable. A partially malfunctioning valve is almost impossible to evaluate clinically. Another problem which frequently plagues the surgeon is the identification of which end of the obstructive system is at fault. Simple radiographic evaluation of the broken tube occurs too infrequently to be of consistent value. Radioactive material, such as iodinated I131 serum albumin (Risa 131), has been utilized1-6 to study cerebrospinal flow through shunt systems. Usually this material is injected into the lateral ventricle and its concentration in the blood stream or in the distal limb of the tubing is determined.