Imaging of cerebrospinal fluid rhinorrhea

Abstract

Cerebrospinal fluid (CSF) rhinorrhea is defined as the leakage of CSF into the nose through an osteodural defect in the skull base, which leads to a fistula between the subarachnoid space and the sinonasal cavity. Since this communication puts the patient at an increased risk of developing meningitis, surgical intervention is required for treatment of continuing CSF rhinorrhea. Accurate detection of the site of CSF leak facilitates appropriate treatment, helping to decrease the risk of life-threatening complications. Recent improvements in imaging technology, particularly the introduction of multi-detector computed tomography (CT), have led to better delineation of skull base defects. Imaging is crucial in precise localization and detailed evaluation of the leak, as demonstration of the exact location, size, and contents of the osteodural defect leads to more accurate planning of surgery. Also, radiological identification of critical adjacent anatomical structures before surgery increases the rate of surgical success with less morbidity. Imaging is essential for CSF rhinorrhea to identify the exact site of the leak, to characterize the osteodural defect, to plan surgery, and to evaluate the underlying cause. Various modalities including HRCT, MRI, and cisternography techniques using CT/MRI or radionuclide scan are described and widely used; however, there is no single best modality. HRCT scanning of the skull base is the modality of choice for depicting the bone defects; however, evaluation of the adjacent soft tissues is best achieved by MRI, making these two cross-sectional tools complementary to each other. HRCT images can also be used for intraoperative image-guided navigation.