The reliability of radiologists' first impression interpreting a screening mammogram

The initial impressions about the presence of abnormality (or gist signal) from some radiologists are as accurate as decisions made following normal presentation conditions while the performance from others is only slightly better than chance-level. This study investigates if there is a subset of radiologists (i.e., "super-gisters"), whose gist signal is more reliable and consistently more accurate than others. To measure the gist signal, images were presented for less than a half-second. We collected the gist signals from thirty-nine radiologists, who assessed 160 mammograms twice with a wash-out period of one month. Readers were categorized as "super-gisters" and "others" by fitting a mixture of Gaussian models to the average Area Under Receiver Operating Characteristics curve (AUC) values of radiologists in two rounds. The median intra-class correlation (ICC) for the "supergisters" was 0.63 (IQR: 0.51-0.691) while the median ICC for the "others" was 0.51 (IQR: 0.42-0.59). The difference between the two groups was significant (p=0.015). The number of mammograms interpreted by the radiologist per week did not differ significantly between "super-gisters" and others (medians of 237 versus 200, p=0.336). The linear mixed model, which treated both case and reader as random variables showed that only "super-gisters" can perceive the gist of the abnormal on negative prior mammograms, from women who developed breast cancer. Although detecting gist signal is noisy, a sub-set of readers have the superior capability in detecting the gist of the abnormal and only the scores given by them are useful and reliable for predicting future breast cancer.