Visual estimation of coronary obstruction severity from angiograms suf
fers from poor inter- and intraobserver reproducibility and is often i
naccurate, In spite of the widely recognized limitations of visual ana
lysis, automated methods have not found widespread clinical use, in pa
rt because they too frequently fail to accurately identify vessel bord
ers, We have developed a robust method for simultaneous detection of l
eft and right coronary borders that is suitable for analysis of comple
x images with poor contrast, nearby or overlapping structures, or bran
ching vessels, The reliability of the simultaneous border detection me
thod and that of our previously reported conventional border detection
method were tested in 130 complex images, selected because convention
al automated border detection might be expected to fail, Conventional
analysis failed to yield acceptable borders in 65/130 or 50% of images
, Simultaneous border detection was much more robust (p < .001) and fa
iled in only 15/130 or 12% of complex images, Simultaneous border dete
ction identified stenosis diameters that correlated significantly bett
er with observer-derived stenosis diameters than did diameters obtaine
d with conventional border detection (p < 0.001), Simultaneous detecti
on of left and right coronary borders is highly robust and has substan
tial promise for enhancing the utility of quantitative coronary angiog
raphy in the clinical setting,