Technetium Tc-99m pyrophosphate for cerebrospinal fluid leaks: radiopharmaceutical considerations

OBJECTIVE To confirm the anticipated image quality and absence of adverse reactions in patients undergoing clinical practice cerebrospinal fluid (CSF) leak imaging procedures using technetium Tc-99m pyrophosphate (PYP). METHODS Following the recent discontinuation of preservative-free calcium trisodium diethylene triamine pentaacetic acid kits, PYP was selected as a suitable alternative for CSF leak imaging procedures. Procedures were established for its preparation and dispensing, paying special attention to safety considerations, and its use in clinical practice was implemented. Medical records, including images, were reviewed for the first 15 patients undergoing clinical practice CSF imaging procedures using Tc-99m PYP to confirm anticipated image quality and absence of adverse effects. RESULTS Review of CSF leak imaging procedures using Tc-99m PYP in 15 patients showed images to be of uniformly high quality. The vast majority of injected radiopharmaceutical remained in the CSF throughout the duration of the imaging procedure, allowing visualization of CSF leaks. Only a small amount of Tc-99m PYP diffused into the blood with resultant uptake on the skeleton and excretion into the urine, which did not interfere with image interpretation. No adverse reactions were noted in any of the patients. CONCLUSION With proper attention to safety considerations, Tc-99m PYP is a safe and effective alternative for performing CSF leak imaging procedures.