Correlation between Computed Tomography and Bone Single Photon Emission-Computed Tomography Scintigraphy in Patients with Chronic Rhinosinusitis

Background Computed tomography (CT) has been the imaging study of choice for evaluating chronic rhinosinusitis (CRS). 99mTc-MDP bone single photon emission-computed tomography (SPECT) has proven useful at identifying inflammation of bone and its use in CRS has been discussed recently. No studies, however, have documented the correlation between these two imaging modalities in CRS. Methods A retrospective analysis was performed of 30 patients with CRS who underwent CT and SPECT scan of the paranasal sinuses. Increased radiotracer uptake during SPECT scan was compared with CT findings graded on the Lund-Mackay score (LMS). The findings of the two imaging modalities were compared and evaluated for standard correlative statistics for diagnostic tests. Results SPECT imaging was abnormal in 25/30 patients, and CT was abnormal in 27/30 patients. Correlation between the two was highest for the ethmoid sinuses at 73.3%. SPECT had a high positive predictive value for mucosal inflammation on CT of 84.1%. Approximately 25% of individual sinuses with a positive SPECT in patients without prior surgery were not positive in corresponding sinuses on CT. There was a positive correlation between the LMS and the number of SPECT positive sinuses within the same patient (r = 0.486; p = 0.006). Conclusion 99mTc-MDP SPECT scan in patients with CRS is shown to be a useful indicator of bone involvement. The relatively high rate of bone involvement in the absence of mucosal inflammation as seen in this study warrants additional research and the potential need for different therapies than are currently available.