Although for the vast majority of patients with spontaneous intracranial hypotension knowledge of the exact site of the underlying spinal CSF leak is not necessary, it is for patients with recalcitrant symptoms. Such patients may require directed treatments such as percutaneous fibrin glue injections or surgery. A variety of MRI techniques have been shown to be able to detect CSF leaks as well and sometimes better than the "gold standard" - CT-myelography. For unusually rapid CSF leaks - particularly those ventral to the spinal cord - digital subtraction myelography or dynamic CT-myelography are indicated. Some patients with spontaneous intracranial hypotension verified by intracranial MRI are never found to have a spinal CSF leak using current techniques.