Purpose: Investigation of the diagnostic efficacy of low dose paranasal sinus CT examination for decreasing the patient radiation dose.
Materials and methods: A limited number of low dose CT sections (5 sections/patient; 30 mAs, n = 30; 60 mAs, n = 30) were performed in addition to standard dose (200 mAs) coronal paranasal sinus CT examination in 60 patients. Previously determined anatomical structures (uncinate process, maxillary ostium, lamina papyracea, fovea ethmoidalis, nasolacrimal canal, ethmoidal infundibulum, ethmoidal bony septae) were scored in terms of detectability and sharpness in both low and standard dose images. The scores of low dose groups were assessed both totally and separately for each anatomical structure, and compared with scores of the standard dose group. Wilcoxon signed ranks test was performed for comparison of the scores.
Results: No significant difference was detected upon comparison of the 60 mAs-group and the standard dose group. The diagnostic quality for the lamina papyracea, fovea ethmoidalis and ethmoidal bony septae were insufficient in the 30 mAs-group compared with the standard dose group. The difference was statistically significant (p < 0.05).
Conclusion: 60 mAs-low dose paranasal sinus CT examinations have sufficient diagnostic quality.