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Search for lesions in mammograms: Statistical characterization of observer responses
Author(s) -
Bochud François O.,
Abbey Craig K.,
Eckstein Miguel P.
Publication year - 2004
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1630493
Subject(s) - gaussian , observer (physics) , pixel , computer science , artificial intelligence , detection theory , contrast (vision) , signal (programming language) , gaussian network model , pattern recognition (psychology) , mathematics , computer vision , statistics , physics , detector , telecommunications , quantum mechanics , programming language
We investigate human performance for visually detecting simulated microcalcifications and tumors embedded in x‐ray mammograms as a function of signal contrast and the number of possible signal locations. Our results show that performance degradation with an increasing number of locations is well approximated by signal detection theory (SDT) with the usual Gaussian assumption. However, more stringent statistical analysis finds a departure from Gaussian assumptions for the detection of microcalcifications. We investigated whether these departures from the SDT Gaussian model could be accounted for by an increase in human internal response correlations arising from the image‐pixel correlations present in 1 / f spectrum backgrounds and/or observer internal response distributions that departed from the Gaussian assumption. Results were consistent with a departure from the Gaussian response distributions and suggested that the human observer internal responses were more compact than the Gaussian distribution. Finally, we conducted a free search experiment where the signal could appear anywhere within the image. Results show that human performance in a multiple‐alternative forced‐choice experiment can be used to predict performance in the clinically realistic free search experiment when the investigator takes into account the search area and the observers' inherent spatial imprecision to localize the targets.