Combined HRCT and MRI in the detection of CSF rhinorrhea

Cerebrospinal fluid (CSF) rhinorrhea is a potentially dangerous problem. Accurate preoperative localization of the site of leakage is mandatory. The standard diagnostic technique is computed tomography (CT) cisternography. Because of its related risks, however, various alternatives have been suggested. High-resolution CT (HRCT) provides good bony details, but fluid is poorly detected. In contrast, T2-weighted magnetic resonance imaging (MRI) shows CSF as a bright signal, but spatial resolution is poor as is the depiction of bony details. To overcome the shortcomings of both techniques, we superimposed the images obtained from each modality and used the result to plan surgical explorations. The sensitivity of HRCT was 88.25%. Fat-suppressed T2-weighted MRI detected a CSF-like density in 18 cases (90%) with a sensitivity of 88.88%. Superimposing the CTs and MRIs accurately localized the site of CSF leakage in 17 of 19 cases with a sensitivity of 89.74%. This finding compares favorably with the results of other techniques. We thus recommend this technique as the primary diagnostic method of choice for the investigation of patients with CSF rhinorrhea.