RADIONUCLIDE CISTERNOGRAPHY AND MRI IN SPONTANEOUS INTRACRANEAL HYPOTENSION SYNDROME (IHS). LOCATION OF CEREBROSPINAL FLUID (CSF) LEAKS AND TREATMENT WITH EPIDURAL BLOOD PATCH (EBP).

Objectives: To evaluate the usefulness of the neuroimaging, MRI and cisternography, in the diagnosis and localization of CSF leaks in patients with spontaneous intracranial hypotension. MATERIAL AND

Methods: Retrospective longitudinal observational study of nine patients with definitive diagnosis of IHS who were treated with an EBP. Clinical presentation: orthostatic headache was the main symptom. Other associated symptoms included nuchal rigidity, neck pain, vertigo, nausea, vomiting, tinnitus and diplopia. There was no history of trauma or iatrogenia. All patients underwent cranial MRI with paramagnetic endovenous contrast; seven of the patients had additional studies of spinal MRI with intravenous contrast (cervical, thoracic and lumbar). The cisternography with 0.5mCi In111 DTPA had been performed in patients with disabling postural headache without clinical improvement after conservative treatment. RESULTS: Radionuclide cisternography: macroscopic leakage was found in all cases (2 cervical, 5 high thoracic, 3 lumbar). No CSF flow progression to cerebral convexity. No nasal or optic fistulas were seen. Cerebral MRI identified enhancement of pachymeninges, subdural fluid collections, sagging brainstem, inferior displacement of the cerebellar tonsils, and engorgement of venous structures. In all cases, the spinal MRI revealed either subdural or epidural fluid collections, engorgement of epidural veins, pachymeningeal enhancement, and the "C1-C2 sign" was shown. Treatment was performed using EBP-guided imaging with one or two patches, showing progressive and complete resolution of the symptoms and without side effects. No patient required further surgical treatment. CONCLUSIONS: IHS is a rare entity with a difficult diagnosis. It requires high quality neuroimaging tests for its detection and early treatment. The evaluation of both techniques, MRI and Radionuclide cisternography, allow to specifically determinate the level of CSF leakage. EBP-guided imaging, according to clinical practice, provides a better chance of therapeutic success compared to a blind performance.