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Regional difference in compression artifacts in low-dose chest CT images: effects of mathematical and perceptual factors

Cited 12 time in Web of Science Cited 14 time in Scopus
Authors
Kim, Kil Joong; Kim, Bohyoung; Lee, Kyoung Ho; Kim, Tae Jung; Mantiuk, Rafal; Kang, Heung-Sik; Kim, Young Hoon
Issue Date
2008
Publisher
American Roentgen Ray Society
Citation
AJR 2008; 191:W30-37
Keywords
artifactsCTdata compressionimage quality metriclow-dose CTlung cancer screeningvisually lossless threshold
Abstract
OBJECTIVE: The objective of our study was to investigate the difference of perceptible artifacts between the lungs and the chest wall and mediastinum in Joint Photographic Experts Group (JPEG) 2000-compressed low-dose chest CT images and to show that a perceptual image quality metric-the High-Dynamic Range Visual Difference Predictor (HDR-VDP)-can reproduce this regional difference. MATERIALS AND METHODS: Twenty images were compressed reversibly and irreversibly to 6:1-30:1. To analyze the two regions separately (lungs; and chest wall and mediastinum), the compressed pixels outside each tested region were replaced with the original pixels. By comparing the compressed and original images, three radiologists independently rated the compression artifacts as grade 0, none, indistinguishable; 1, barely perceptible; 2, subtle; or 3, significant. At each compression level, the two regions were compared for the readers' responses, peak signal-to-noise ratio (PSNR), and HDR-VDP results. Wilcoxon's signed rank tests and exact tests for paired proportions were used with a p value threshold of 0.05. RESULTS: Artifacts were rated as lower grades in the lungs than in the chest wall and mediastinum, showing statistical significances at 10:1-20:1 for reader 1, 8:1-15:1 for reader 2, and 8:1-20:1 for reader 3. Grade 0 was more frequent in the lungs, showing statistical significances at 10:1 for reader 1 and at 8:1-10:1 for readers 2 and 3. The results of PSNR indicated greater artifacts in the lungs (p < 0.001), whereas HDR-VDP results indicated fewer artifacts in the lungs (p < 0.001). CONCLUSION: Although compression artifacts are mathematically greater in the lungs than in the chest wall and mediastinum, radiologists' artifact perceptions are the opposite, which can be successfully reproduced by HDR-VDP.
ISSN
1546-3141 (Electronic)
Language
English
URI
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18647883

https://hdl.handle.net/10371/10600
DOI
https://doi.org/10.2214/AJR.07.3462
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Radiation Applied Life Science (대학원 협동과정 방사선응용생명과학전공)Journal Papers (저널논문_방사선응용생명과학전공)
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