BI-RADS classification and gray level histogram of malignant mammary tumors in bitches

Abstract

Oliveira D.M.N.M., Costa F.S. & Wischral A. 2018. BI-RADS classification and gray level histogram of malignant mammary tumors in bitches. Pesquisa Veterinária Brasileira 38(10):1942-1948. Mammary tumor is the most frequent among the tumors that affect canine females, with relevant importance in veterinary medicine. The objective of this study was to determine the image characteristics of mammary tumors in female dogs, and compare different ultrasonographic techniques for neoplastic evaluation. During the experiment, 30 bitches with presence of nodular lesion in the mammary gland were used. Initially females were submitted to clinical and laboratory evaluations, and subsequent to the ultrasound examination of the tumor mass, as well as abdominal ultrasound and thoracic x-ray for the metastasis investigation. Quantitative analysis by histogram of the gray levels and categorization of the tumor masses by the BI-RADS system were performed. Later, the bitches were submitted to surgical resection of the tumors, where samples of the neoplastic tissue were collected for histopathological analysis. Carcinoma in mixed tumor showed a higher rate (33.3%), and the malignancy degree of epidermal tumors were classified in grade 1 (n=9), grade 2 (n=12) and grade 3 (n=3). Malignancy degree showed positive correlation with BI-RADS (r=0.55; P<0.05) and with the parameter echotexture -histogram base width (r=0.42, P<0.05). BI-RADS graduation also showed a positive correlation with the echotexture parameters (standard deviation of average echogenicity r=0.66, P<0.05 and base width r=0.55, P<0.05). It was concluded that the BI-RADS method in combination with the echotexture of tumors, can be used to evaluate mammary tumors in dogs and establish the planning of treatment.

The Importance of Ultrasonography in the Evaluation of Mammary Tumors in Bitches

“…In 2011, a study conducted by Mohammed et al [34] proposed a standardized method for canine mammary ultrasound evaluation regarding lexicon, reporting and grading based on the well-known BI-RADS™ (Breast Imaging Reporting and Data System) method established in human medicine by the American College of Radiology [36]. This systematic approach was further explored in 2018 by Oliveira and colleagues [37]. The terminology proposed by these studies for sonographic reporting can be found in Table 1.…”

“…Quantitative assessment of mammary tumors has been attempted to investigate whether it is possible to discriminate between malignant and benign lesions based on quantitative information of echogenicity and echotexture [37,38]. These studies have reported that computer-assisted echotexture analysis is an important feature that presents predictive value to differentiate benign from malignant lesions, where heterogenicity is often observed in malignant tumors.…”

“…Further studies could be implemented in order to evaluate the possibility of computer-assisted echostructure analysis using higher frequency transducers. These sonographic findings can be used to classify the mammary lesion in six different categories according to the modified BI-RADS classification proposed for bitches with mammary tumors [34,36,37]. The BI-RADS categories and their common findings can be found in Table 2.…”

“…The BI-RADS categories and their common findings can be found in Table 2. These studies conducted to validate the Modified BI-RADS classification demonstrated that Categories 3 to 5 have higher chances of presenting malignancy, where Category 5 presents higher malignancy incidence [34,36,37]. However, it is prudent to consider that these findings and reporting systematization do not provide definitive diagnosis and that biopsy would be required for diagnostic elucidation.…”