Investigation of choice for leptomeningeal carcinomatosis
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
PET
SPECT
Gd enhanced MRI
CT scan
C.N.S