Applying computer-assisted detection schemes to digitized mammograms after JPEG data compression: an assessment.
OBJECTIVE
The authors' purpose was to assess the effects of Joint Photographic Experts Group (JPEG) image data compression on the performance of computer-assisted detection (CAD) schemes for the detection of masses and microcalcification clusters on digitized mammograms.


METHODS
This study included 952 mammograms that were digitized and compressed with a JPEG-compatible image-compression scheme. A CAD scheme, previously developed in the authors' laboratory and optimized for noncompressed images, was applied to reconstructed images after compression at five levels. The performance was compared with that obtained with the original noncompressed digitized images.


RESULTS
For mass detection, there were no significant differences in performance between noncompressed and compressed images for true-positive regions (P = .25) or false-positive regions (P = .40). In all six modes the scheme identified 80% of masses with less than one false-positive region per image. For the detection of microcalcification clusters, there was significant performance degradation (P < .001) at all compression levels. Detection sensitivity was reduced by 4%-10% as compression ratios increased from 17:1 to 62:1. At the same time, the false-positive detection rate was increased by 91%-140%.


CONCLUSIONS
The JPEG algorithm did not adversely affect the performance of the CAD scheme for detecting masses, but it did significantly affect the detection of microcalcification clusters.
Zheng
B
B
Department of Radiology, University of Pittsburgh, PA 15261-0001, USA.
Sumkin
J H
JH
Good
W F
WF
Maitz
G S
GS
Chang
Y H
YH
Gur
D
D
D000465:Algorithms; D001941:Breast Diseases / Q000000981:diagnostic imaging*; D003936:Diagnosis, Computer-Assisted; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods*; D010781:Photography; D012815:Signal Processing, Computer-Assisted