Ultrasonography of Liver Metastases The 1st report : Studies on B-mode Imaging by Real-time Ultrasound and Ultrasound guided Aspiration Biopsy

The diagnostic accuracy of B-mode real-time ultrasonography on liver metastatic tumors of 1,192 patients was analysed. In parallel, ultrasound-guided fine needle aspiration cytology or needle biopsies were performed in some cases suspected for liver metastasis. The ultrasound diagnosis of liver metastasis were correct in 286 （94.7%） of 302 cases. On laparotomy, 52 cases of liver metastasis were further found from 890 patients who had shown negative findings. The overall accuracy was 94.3%, sensitivity was 94.7%, specificity was 94.2%, positive predictive value for metastatic Ca. was 84.6%, and negative predictive value was 98.1% in the diagnosis of liver metastasis. US-guided liver aspiration cytology was performed in 79 cases, malignant cells were found in 67. The overall accuracy rate was 84.8%, with a sensitivity of 85.9%, a specificity of 100%, and a positive predictive value of 100%. A histologic study of tissue fragment preparations was performed for 45 of 53 cases with 21-gauge biopsy needles by histologic examination biopsy. The overall accuracy rate of the histologic biopsy evaluation was 88.7%, with a sensitivity of 88.2%, a specificity of 100%, and a positive predictive value of 100%. False-negative results were seen in 11 cases of the cytologic, and in 6 cases of the biopsy specimens. Combined cytology and biopsy evaluations were performed in 38 cases. The histologic diagnosis were obtained in 45 cases by histologic biopsy, and in 16 cases only by aspiration cytology. There were not any false-positive result or any serious complications in either examination. The majority of liver metastases showed varied small （less than 30mm）, multiple lesions in the liver. Five echoic patterns were classified in this paper. The hyperechoic pattern were 124 cases （43.4%）, and hypoechoic pattern were 92 cases （32.2%）. The lesions smaller than 30mm discovered by US were in 215 （75.2%） of 286 cases of liver metastases. There were 273 cases suffering multiple lesions, 87 cases in the right, 24 cases in the left lobe, and 162 cases in the whole of the liver. Fifty-four cases had single lesions, found in the left lobe in 25 （46.3%） and the right lobe in 29 （53.7%） cases. The "bull's eye" sign or "target" sign is an important characteristic pattern of liver metastasis under US. Calcification or necrosis may occur in some lesions. It is difficult to find a smaller lesion in the fornix of the right liver lobe or when it is an isoechoic pattern metastasis, and when the liver is? heterogenous as when caused by bile stagnation or other etiologies. We conclude that US is very useful in the clinic to check-up or follow-up in liver metastasis, and ultrasound-guided fine needle aspiration cytology or needle biopsy are powerful arms for diagnosing hepatic tumors.