ROC and contrast detail image evaluation tests compared.

Abstract

Using both contrast detail and receiver operating characteristic (ROC) evaluation tests, we evaluated different quality images, produced with different film-screen combinations. ROC curves were obtained for six observers who were attempting to detect lung nodules and pulmonary infiltrates. The contrast detail curves were obtained from images of regular circular test patterns of differing contrast, which had been presented to the observers. Our results indicate that contrast detail tests can be used for relative ranking of image systems prior to detailed ROC testing.

Dual-Energy Digital Mammography with a Full-Field aSi/CsI Flat-Panel Imager

“…35), it is necessary to compute the coefficients, k (j (Eqs. [27][28][29][30] and the SNR for low-and highenergy images, SNR S (Eq. 22).…”

“…[25][26][27][28][29][30][31][32][33][34][35] Contrast-detail curves of different digital chest systems have been independently studied without being compared to each other. Due to inter-reader variations are differences in study conditions (x-ray techniques, reading and scoring, etc.…”

“…H-m molybdenum filter (Mo/Mo) at 25,30,35,40,45 and 50 kVp; and for a tungsten target and lanthanum filter (W/La) at 50 kVp. The mammographic spectra were used in computations for both single-and dual-energy imaging.…”

“…Using a 250 (Xm fiC size, the fiC image noise, <7 t was computed for various kVp combinations: low-energy spectrum fixed at 25 kVp (Mo/Mo) and high-energy spectra at 30,35,40,45 and 50 kVp (Mo/Mo). At 50 kVp, the W/La target/filter combination was also used.…”

“…A fixed low-energy spectrum (25 kVp) and various high-energy spectra (30,35,40,45 and 50 kVp) were used. A 50 kVp W/La target/filter combination was also used as the high-energy spectra in the calculation, o, was plotted as a function of the low-energy exposure ratio for various Mo/W dual-target tube is not known to be commercially available.…”