Role of ultrasonography and MRI in the detection of wide intraductal component of invasive breast cancer—a prospective study

Aim To compare the role of ultrasound (US) and magnetic resonance imaging (MRI) in the detection of extent and direction of intraductal components around invasive breast cancer in comparison with histopathological findings. Materials and methods In 60 invasive breast cancers (59 patients), US features of the intraductal components were classified as: (a) solid ductal dilatation radiating from the tumour, (b) the presence of a satellite lesion in the same segment without ductal dilatation, (c) ductal dilatation between the main tumour and the satellite lesion. The criteria for the detection of intraductal components by MRI were as follows: (a) strand-like enhancement on the margin of the main tumour, (b) satellite lesions around the main tumour, or (c) bridging enhancement between the main tumour and the satellite lesion. The direction of the intraductal components was classified as towards the nipple and towards the periphery. Results Wide intraductal components (≥15 mm) towards the nipple were proven histopathologically in 17 of 59 (28.8%) cancers, and wide intraductal components towards the periphery were proven histopathologically in three out of 60 (5.0%) cancers. One cancer was located too close to the nipple and it was not possible to measure the intraductal component towards the nipple. US and MRI could accurately detect wide intraductal components towards the nipple in 14 and 8 cancers, respectively, out of 17 cancers. Sensitivity, specificity and accuracy for detection of wide intraductal components towards the nipple by US were 87.5, 88.3, and 88.1%, respectively. Sensitivity, specificity and accuracy for detection of wide intraductal components towards the nipple by MRI were 50, 79.1, and 72.1%, respectively. When the results of both diagnostic methods namely US and MRI were combined, sensitivity rose to 93.7%, specificity was 72.1% and accuracy was 78.0%. Conclusion Although ultrasound is more sensitive than MRI in the delineation of intraductal extension towards the nipple, there is no statistically significant difference in overall accuracy between the two modalities.