Is image manipulation necessary to interpret digital mammographic images efficiently?

With the introduction of digital breast screening across the UK, screeners need to learn how best to inspect these images. A key advantage over mammographic film is the facility to use workstation image manipulation tools. Forty two-view FFDM screening cases, representing malignant, normal and benign appearances were examined by fourteen radiologists and advanced practitioners from two UK screening centres. For half the cases, the mammography workstation image manipulation tools could be employed and for the other half these were not used. Participants classified each case and indicated whether an abnormality was present. Throughout the study the participants’ visual search behaviour as well as their image manipulations was recorded. Whether or not image manipulation tools were used made very little difference to overall performance (t-test, p>.05) as confirmed by JAFROC analysis Figure-Of-Merit values of 0.816 and 0.838 (with and without tools respectively); performance not using tools was better. However, using tools significantly increased inspection time (p<0.5) as well as participants’ confidence. Detailed examination of participants’ image inspection behaviour elicited that the average time on each case in the different viewing conditions differed significantly between the high experienced readers and low experienced readers. The visual data analysis revealed that the participants made similar overall pattern of errors on both modalities. The visual search behaviour on both modalities are surprisingly similar.