How is a CSF scintigraphy study performed, and what is it used for?
CSF scintigraphy typically involves the administration of a radiotracer such as 99m Tc DTPA into the CSF (usually via injection through a lumbar puncture at the base of the spinal column). Planar scintigraphic images are obtained initially and then at regular intervals up to 24 hours (i.e., 2, 4, 6, 12, and 24 hours) depending on the rate of flow and the purpose of the scan. There are two primary diagnostic purposes of CSF scintigraphy studies: evaluation of hydrocephalus and evaluation for a CSF leak. The evaluation of hydrocephalus requires imaging to determine the rate of CSF flow and any areas in which CSF flow is abnormal. The evaluation of a CSF leak explores various areas along the CSF spaces in which an abnormal accumulation of radiotracer occurs. CSF studies are sometimes performed with the use of pledgets placed into the nasal cavity to measure asymmetries in radiotracer accumulation. This can help to detect a leak even if it is not specifically observed on the scans.