
Fig. 3. Graph shows alternative free-response receiver operating
characteristic (ROC) curves of every monitor condition averaged for all six
observers. Az = area under alternative free-response ROC
curve. a and b represent vertical intercept and slope,
respectively, of alternative free-response ROC curve when it is plotted on
normaldeviate axes. Note that with regard to area under average
alternative free-response ROC curve, 1K monitor with postprocessing (0.73
± 0.081) and 2K monitor with (0.75 ± 0.101) and without (0.75
± 0.109) postprocessing have equivalent results in detecting pulmonary
nodules in digital chest radiographs in clinical interpretation environment.
1K monitor without postprocessing performed poorly (0.69 ± 0.086). 1K
overview, a = 0.65, b = 0.81, Az =
0.6931. 2K overview, a = 0.86, b = 0.76,
Az = 0.7524. 1K with postprocessing, a = 0.81,
b = 0.84, Az = 0.7330. 2K with postprocessing,
a = 0.85, b = 0.75, Az = 0.7504.