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

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.