RT Journal Article SR Electronic T1 Detection of discrete white matter lesions after irreversible compression of MR images. JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 1435 OP 1440 VO 16 IS 7 A1 D A Clunie A1 P J Mitchell A1 J Howieson A1 S Roman-Goldstein A1 J Szumowski YR 1995 UL http://www.ajnr.org/content/16/7/1435.abstract AB PURPOSE To validate the use of techniques of irreversible compression of images, which can be performed using a block-based discrete cosine transform technique as defined by the Joint Photographic Experts Group, before they can be used in clinical applications, by evaluating the effect of compression on the ability of observers to detect discrete white matter lesions on MR images of the brain. METHODS Sixty T2- and intermediate-weighted spin-echo images were compressed with varying degrees of coefficient quantization with compression ratios from 1:1 to more than 40:1, randomized, and evaluated by three observers blinded to the degree of compression. RESULTS No significant difference in the number of lesions detected was apparent until compression ratios reached 40:1, despite a significant subjective loss in perceived image quality at 20:1. Only small (< or = 5 mm) lesions were missed at the highest degree of compression. No significant differences were observed in the detection of confluent periventricular white matter disease at any degree of compression tested. CONCLUSIONS The use of high degrees of irreversible compression of MR images may be acceptable for diagnostic tasks.