Investigation of choice for leptomeningeal carcinomatosis
PET
SPECT
Gd enhanced MRI
CT scan
To detect leptomeningeal metastases, gadolinium-enhanced MRI is more sensitive than CT scanning. The sensitivity of MRI is nearly 70% while that of CT scan is around 30%. The most common MRI findings consist of typical nodules in the subarachnoid and parenchymal regions, parenchymal volume loss and sulcal/dural enhancement CT-myelography is not indicated due to low sensitivity, whereas the value of FDG PET ,SPECT scan is still under investigation Ref Harrison20th edition pg 2234
C.N.S