Radioisotope cisternography in spontaneous CSF leaks: interpretations and misinterpretations.

A broadening of the clinical and imaging features of the spontaneous cerebrospinal fluid (CSF) leaks is now well recognized, far beyond what was thought only two decades ago. This has resulted in increasing number of patients with atypical and unusual features who, not unexpectedly, are directed to headache specialists and tertiary referral centers. In many cases, obviously the fundamental question of presence or absence of CSF leak will need to be addressed prior to proceeding with further and often more involved, more invasive, and more costly diagnostic and therapeutic considerations. Radioisotope cisternography often proves to be very helpful in these situations by demonstrating reliable, although indirect, evidences of CSF leak while it is less helpful in directly identifying the exact site of the CSF leakage. In this overview article, the expectations from and the limitations of this diagnostic method are described along with some personal observations in the past 25 years.