JPEG2000 compression of thin-section CT images of the lung: Effect of compression ratio on image quality

Helmut Ringl, Ruediger E. Schernthaner, Alexander A. Bankier, Michael Weber, Mathias Prokop, Christian J. Herold, Cornelia Schaefer-Prokop

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Purpose: To assess retrospectively the effect of the Joint Photographic Experts Group 2000 (JPEG2000) compression ratio on the quality of thin-section computed tomographic (CT) images. Materials and Methods: In this institutional review board-approved investigation (protocol 238/2004), thin-section CT images were subjected to irreversible JPEG2000 compression by using five compression ratios (3:1, 5:1, 7:1, 9:1, and 11:1). Three radiologists independently evaluated 60 thin-section CT images, of various diseases, that were obtained with single-detector (weighted dose index, 14.4 mGy) and multi-detector (weighted dose index, 9.8 mGy) CT. Toggling between the original and compressed images, readers had to identify the original image by using a forced-choice two-alternative model and to subjectively rank the quality of what they believed to be the compressed image. To assess the reader's ability to distinguish the compressed from the original image, a binomial test was used. Bonferroni correction was applied for all multiple tests. Results: Images compressed with a ratio of 3:1 were not distinguishable from original images (P > .2 for all readers). With use of the 5:1 ratio, minor differences in appearance between the compressed and original images were seen by one of the three readers. With use of higher compression ratios (≥7:1), all readers (P < .001) recognized the original image. The quality of more than 90% of the images compressed with a 7:1 or higher ratio was substantially degraded. Single-detector and multidetector CT results were not significantly different. Conclusion: The highest ratio that yielded visually lossless compression of thin-section CT images was 3:1. With the 5:1 ratio, there was minor image quality loss, while use of higher compression ratios (≥7:1) caused substantial degradation of image quality and potential loss of diagnostic information.

Original languageEnglish (US)
Pages (from-to)869-877
Number of pages9
Issue number3
StatePublished - Sep 2006
Externally publishedYes

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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