Objective: This study was designed to compare low- and standard-dose multidetector CT (MDCT) findings in patients with suspected chronic sinusitis. SUBJECTS AND METHODS. Fifty patients underwent MDCT at 10 and 150 effective mAs. The low-dose MDCT protocol delivered a radiation dose of 0.047 mSv in men and 0.051 mSv in women, whereas the standard-dose MDCT protocol delivered a radiation dose of 0.70 mSv in men and 0.76 mSv in women. Scans of the right and left sides of sinonasal cavities were reviewed by three radiologists, with each physician reviewing a scan twice over an interval of more than 2 weeks. The reviewers were asked to evaluate the scans for eight mucosal and two bone abnormalities. We calculated the number of discrepancies in observed abnormalities between pairs of reviewers, among all three reviewers, and between findings on scans acquired with the two radiation doses.
Results: The mean number of discrepancies in observed abnormalities on scans acquired with different radiation doses ranged from 0 to 5.2. Discrepancies between pairs of reviewers ranged from 1.0 to 12.8 for low-dose scans and from 1.0 to 13.0 for standard-dose scans. Discrepancies among all reviewers ranged from 1.0 to 10.3 for low-dose scans and from 1.0 to 8.7 for standard-dose scans. In analyzing cases of significant discrepancies in observations, we found greater variation between pairs of reviewers and among all three reviewers than between findings obtained with different dose levels.
Conclusion: Dose reduction played a far less important role in discrepancies of detected abnormalities than did the human element of reviewer observation. Given this finding and the fact that low-dose MDCT delivers a radiation dose that is no higher than that delivered by a four-view radiographic examination, low-dose MDCT should be considered the imaging method of choice in patients with suspected chronic sinusitis.