Inter-observer variability in the interpretation of mammograms.

Inter-observer agreement was tested in the interpretation by 8 radiologists of mammograms from 45 women (for a total of 180 films per radiologist). The radiologists were representative of the whole range of those involved in mammography in the town of Torino, with a number of films read per year ranging from 100 to 4000. Out of the 45, 9 women were affected by breast cancer (histologically proved), 25 had benign disease (diagnosed with fine-needle aspiration) and 11 had normal breasts. Weighted kappa values were in the range 0.27-0.82 (median 0.60) for parenchymal patterns; 0.33-0.67 (0.48) for diagnosis in five categories; and 0.22-0.57 (0.38) for indications for further diagnostic tests. These values are comparable with those reported from other investigations.