Evaluation of ventriculoatrial or ventriculoperitoneal shunt patency.
No special preparation. A thorough description of the shunt anatomy should be provided to Nuclear Medicine prior to injection. Shaving the hair over the shunt reservoir may be necessary.
1 mCi Tc-99m MAA or sulfur colloid is injected using sterile technique into the shunt reservoir. The exact injection technique depends on the type of shunt. The injection is performed by the neurosurgeon or nuclear medicine physician.
If the shunt is patent, activity should appear in the abdomen (or lung) within 15-20 minutes after infusion. Occasionally imaging times of 30 minutes to an hour or more are needed.
Manual occlusion of the distal limb of the shunt may cause reflux into the proximal limb and ventricles allowing evaluation of these areas.
The radiopharmaceutical is injected into the shunt reservoir and its flow with the CSF is the basis for imaging.