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Performance changes in lung nodule detection following perceptual feedback of eye movements.

Research output: Contribution in Book/Report/ProceedingsChapter


Publication date5/03/2008
Host publicationMedical Imaging 2008: Image Perception, Observer Performance, and Technology Assessment
EditorsBerkman Sahiner, David J. Manning
Place of publicationUSA
Original languageEnglish

Publication series

NameProceedings of the SPIE


In a previously reported study we demonstrated that expert performance can decline following perceptual feedback of eye movements in the relatively simple radiological task of wrist fracture detection [1]. This study was carried out to determine if the same effect could be observed using a more complicated radiological task of identifying lung nodules on chest radiographs. Four groups (n=10 in each group) of observers with different levels of expertise were tested. The groups were naïve observers, level 1 radiography students, level 2 radiography students and experts. Feedback was presented to the observers in the form of their scan paths and fixations. Half the observers had feedback and half had no perceptual feedback. JAFROC analysis was used to measure observer performance. A repeated measures ANOVA was carried out. There was no significant effect between the pre and post “no feedback” condition. There was a significant difference between the pre and post “feedback” condition with a significant improvement following feedback (F(1,16)=6.6,p = 0.021). Overall the mean percentage improvement was small of 3.3%, with most of the improvement due to the level 1 group where the percentage increase in the figure of merit (FOM) was 8.4% and this was significant (p<0.05). Eye tracking metrics indicate that the expert and naïve observers were less affected by feedback or a second look whereas there were mixed results between the level 1 and level 2 students possibly reflecting the different search strategies used. Perceptual feedback may be beneficial for those early in their training.