Program Information
New Display Window Setting for Detecting Subtle But Clinically Relevant Artifacts in Daily CT Quality Control
Z Long*, M Bruesewitz , C Favazza , J Kofler , S Leng , C McCollough , L Yu , Mayo Clinic, Rochester, MN
Presentations
TU-C2-GePD-IT-4 (Tuesday, August 1, 2017) 10:00 AM - 10:30 AM Room: Imaging ePoster Theater
Purpose: Subtle artifacts can be overlooked during daily CT quality control (dQC) and mimick diseases in patient images which may result in misdiagnosis. This study aimed to investigate the effect of display window setting on technologist performance detecting these subtle but clinically relevant artifacts in dQC images.
Methods: 53 sets of dQC images were retrospectively selected, including 30 sets without artifacts and 23 sets with artifacts. These artifacts were confirmed to result from scanner-related issues, including detector defects, contrast spills, air calibration with pillows in the scan plane, and air bubbles in the x-ray tube cooling oil. Images were randomized and shown to 6 CT technologists (2 new and 4 experienced). Each technologist reviewed all images in each of two sessions, one with a display window width (WW) of 100 HU (recommended by the ACR), and the other with a narrow WW of 40 HU, both at a window level (WL) of 0 HU. For each case, technologists rated the presence of image artifacts based on a 5 point scale. The area under the receiver operating characteristic curve (AUC) was used to evaluate the artifact detection performance.
Results: At a WW of 100 HU, the AUC (95% confidence interval) was 0.658 (0.576, 0.740), 0.532 (0.429, 0.635), and 0.616 (0.543, 0.619) for the experienced, new, and all technologists, respectively. At a WW of 40 HU, the AUC was 0.768 (0.687, 0.850), 0.546 (0.433, 0.658), and 0.694 (0.619, 0.769), respectively. The performance significantly improved at WW of 40 HU for experienced technologists (p = 0.009) and for all technologists (p = 0.040).
Conclusion: Use of a narrow display WW significantly improved technologists’ performance in dQC for detecting subtle but clinically relevant artifacts as compared to that using a 100 HU display WW. Artifact cases can be used for further technologist training.
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