Comparison of breast ductal branching pattern classification using x-ray galactograms and MR autogalactograms

摘要

We have analyzed the branching patterns of the breast ductal network visible in magnetic resonance (MR) autogalactograms - images of breast ducts which appear enhanced due to the presence of proteinacous or hemorrhagic material in the ducts. The enhanced portions of the ductal network were segmented separately in MRI slices acquired with a 3D GRASS sequence. A semi-automated region growing algorithm was used for segmentation. The ductal network was manually constructed from the segmented portions in each slice. The branching pattern was analyzed by calculating ramification (R-) matrices, whose elements represent the probabilities of branching at various levels of a ductal tree. The R-matrix elements have been used to classify the analyzed cases into those with and without radiological findings. The classification accuracy was estimated using the radiologists' reports as ground truth. An ROC analysis was performed to assess the classification accuracy. The classification of nine MR autogalactograms from eight women yielded an area under the ROC curve of A=0.73. This performance is comparable with our previous analysis of 25 2D x-ray galactograms from 15 women (A = 0.88). The observed results support our hypothesis that a relationship exists between the topological properties of the breast ductal network and the underlying breast pathology.