Contrast harmonic ultrasonography of splenic masses and associated liver nodules in dogs.

OBJECTIVE: To determine whether contrast harmonic ultrasonography (CHUS) can be used in dogs to distinguish splenic hemangiosarcoma from hematoma and to accurately detect and characterize liver nodules.
DESIGN: Cross-sectional study. ANIMALS: 20 dogs with a splenic mass. PROCEDURES: Routine abdominal ultrasonography was followed by CHUS of hepatic and splenic lesions. Qualitative evaluation included location, enhancement pattern, and vascularity of lesions. Quantitative evaluation included peak mean pixel intensity, interval to peak intensity, area under the curve (spleen), and liver-to-lesion intensity ratio (liver). Histologic findings were compared with CHUS lesion characteristics.
RESULTS: Histologic evaluation of the spleen was performed in 19 dogs, resulting in diagnoses of hemangiosarcoma (n=11), hematoma (7), and undifferentiated sarcoma (1). Benign and malignant processes in the spleen were indistinguishable via CHUS. Histologic evaluation of the liver was performed in 18 dogs, resulting in a diagnosis of hemangiosarcoma in 5 dogs. None of the dogs with splenic hematomas had evidence of hepatic lesions by means of conventional or contrast ultrasonography, and none had histologic evidence of liver metastases. In 3 of 18 dogs, isoenhancing liver nodules were detected and all were histologically benign. Five dogs had liver nodules that remained hypoechoic after contrast agent was injected; all had histologic evidence of metastatic hemangiosarcoma. Results of CHUS were used to characterize hepatic metastases with 100% sensitivity and specificity. CONCLUSIONS AND CLINICAL RELEVANCE: Contrast harmonic ultrasonography was a noninvasive and accurate means of differentiating metastatic versus benign hepatic disease in dogs with splenic hemangiosarcoma but was not useful in distinguishing splenic hemangiosarcoma from hematoma.