Evaluation of CSF flow by whole-body scintigraphy

Objectives Spinal fluid leakage is a difficulty diagnosis because of the intermittency and multiple possible locations. Spinal fluid blockage may prevent intrathecal application of therapeutic agents. Conventional imaging modalities suffer from low sensitivity. The bluk flow dynamics of tracer within the entire CSF pathway is thus studied to correlate with both types of flow aberrations.

Methods 276 consecutive whole-body cisternograms were retrospectively reviewed. Serial whole-body images at 1-2, 3-6, 16-20 and 22 to 25 hours were acquired using a dual-headed gamma camera. Half-lives of In-111 DTPA in CSF pathway were calculated from geometric-mean images. Correlation is made with visual image inspection, nasal pledgett counts, MRI report of CSF blocks and clinical symptoms and openning status of VP shunts valve.

Results Visual inspection found leakage in 23/66 patients. 30/66 leakage were found when nasal pledgetts were included. The half-lives of In-111 DTPA were 9.9 ± 4.1 and 8.9 ± 3.8 H for the 2 groups and those without leakage were 15.8 ± 4.8 H (P<0.001). For 10/13 patients with VP shunts, openning VP shunt valve is associated with lower T1/2= 7.1 ± 4.1 H (P<0.001). CSF blockage is associated with elevated T1/2=26.5 ± 2.8 hours (P<0.001) in 3 /12 with closed VP shunt. In 33 patients with CSF block, the T1/2 (16.1 ± 7.8 H) is similar to those of 122 with no CSF block (T1/2=15.9 ± 4.7 H).

Conclusions Whole-body images for CSF clearance of tracers provides a direct and convenient method to determinate CSF leakage. Whole-body In-111 DTPA clearance rate is a useful indicator for CSF leakage but is of limited use to identify CSF blockage.

Research Support NIH R21CA9772