Comparison of low dose and standard dose CT in the evaluation of inflammatory diseases of paranasal sinuses

Abstract

PURPOSE: The aim of this study was to investigate the diagnostic value of low dose CT (LDCT) by comparing the identification of sinonasal anatomical structures, anatomic variations and detectability of inflammatory changes at low and standard dose CT (SDCT). MATERIALS AND METHODS: A total of 30 patients who were referred to CT scan for the assessment of paranasal sinuses underwent CT examinations at both standard [110 mA, 120 kV, 5 mm collimation (3 mm collimation at the level of the ostiomeatal unit)] and low dose [22 mA, 120 kV, 5 mm collimation (3 mm collimation at the level of the ostiomeatal unit)]. All images were photographed at identical window settings (window width, 4000 HU; window level, 50 HU) on laser film. Ten sinonasal anatomical structures (five on the right and five on the left) and inflammatory mucosal changes were recorded for each patient. The detectability and conspicuity levels were scored for each finding. RESULTS: A total of 297 sinonasal anatomical structures were identified at SDCT, whereas 296 structures were detected at LDCT. Inflammatory mucosal changes and anatomical variations were equally identified at both SDCT and LDCT (p > 0.05). There was no statistically significant difference between SDCT and LDCT in the detection on of anatomical structures, variations and inflammatory changes (p > 0.05). CONCLUSION: The low dose CT protocol used in this study provided images of adequate quality, and proved to be reliable in the evaluation of normal and diseased paranasal sinuses.