American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase I: The effect of lossy data compression on recognition of diagnostic features in digital coronary angiography.
OBJECTIVE
This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features.


BACKGROUND
Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography.


METHODS
At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined.


RESULTS
Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80% p = 0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, p < 0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1.


CONCLUSIONS
With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.
Kerensky
R A
RA
University of Florida, Gainesville 32610-0277, USA.
Cusma
J T
JT
Kubilis
P
P
Simon
R
R
Bashore
T M
TM
Hirshfeld
J W
JW
Holmes
D R
DR
Pepine
C J
CJ
Nissen
S E
SE
D000328:Adult; D000368:Aged; D000465:Algorithms; D000704:Analysis of Variance; D015982:Bias; D002309:Cardiology; D017023:Coronary Angiography / Q000592:standards*; D003327:Coronary Disease / Q000145:classification / Q000000981:diagnostic imaging*; D005060:Europe; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000592:standards*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method; D012955:Societies, Medical; D014481:United States