Image quality and dose reduction in sinus computed tomography using iterative reconstruction: a cadaver study

Abstract

Introduction: Concerns about radiation dose in computed tomography (CT) imaging have renewed interest in iterative reconstruction (IR), a technique which has the potential to produce images with less noise at lower radiation doses than traditional filtered back projection (FBP). This study aimed to assess whether application of IR could provide comparable quality sinus CT images to FBP at lower kilovolt (kV) and milliamp (mA) settings, and to establish optimal scan settings for sinus imaging. Methods: 30 sinus CT scans were performed on 5 cadaver heads at two kV setting and three mA settings. Each scan was reconstructed using FBP and 3 IR settings, yielding a total of 120 image series. Each image set was blinded and randomly reviewed by 3 rhinologists and 2 neuroradiologists. Using a 5-point Likert scale, 16 anatomical landmarks, were graded with respect to image quality. Data were assessed with respect to dose and IR settings using statistical analysis. Results: Higher kV and mAs settings produced significantly higher quality images for structure identification across all 16 landmarks; however, the suitability for surgery did not increase in a linear fashion and plateaued by a total radiation dose of 0.1201 mSv. IR algorithm did not provide a benefit in the overall score of scans at a fixed kV and mAs. Conclusions: Identification of structures in sinus CT imaging significantly correlates with the kV and mA and overall dose of radiation; however, IR did not provide additional benefit in the image quality. Blinded reviewers unanimously agreed that scans obtained at 100 mV and 120 mA were acceptable for surgery independent of IR.

Keywords

• sinus anatomy
• computed tomography
• radiology
• imaging
• computer assisted surgery