Pectoral Muscle Removal in Digital Mammograms Using Region Based Standard Otsu Technique

Abstract

Mammography is usually the first preference of imaging diagnostic modalities used for breast cancer detection in the early stage. Two projections Cranio Caudal (CC) and Medio-Lateral Oblique (MLO), used during digital mammogram acquisition depict different degrees for visualizing breast tissues; the MLO view shows more breast tissue and Pectoral Muscle (PM) area when compared to the CC view. Although the PM is a criterion used for proper positioning, it can result in biased results of mammographic analysis like cancer detection and breast tissue density estimation because the PM area has a similar or even higher intensity than breast tissue and breast lesions if present. This paper proposed a Region Based Standard Otsu thresholding method for the elimination of PM area present in MLO mammograms. The developed algorithm was implemented using 322 digital mammograms from the Mammographic Image Analysis Society (MIAS) database, and the difference between the PM detected and the manually drawn PM region by an expert was evaluated. The results showed an average: Jaccard Similarity Index, False Positive Rate (FPR) and False Negative Rate (FNR) of 93.2%, 3.54%, and 5.68% respectively, and also an acceptable rate of 95.65%.