Color Doppler sonography and resistivity index in the differential diagnosis of hepatic neoplasm

The purpose of this study was to determine the usefulness of color doppler sonography and resistivity index (RI) in differentiating liver tumors. The study was carried out in the Department of Radiology and Imaging, Mymensingh Medical College Hospital, and Institute of Nuclear Medicine and Allied Sciences (INMAS), Mymensingh, Bangladesh, during the period of July 2009 to June 2011. Total 50 consecutive cases were studied. Among them 27 were hepatocellular carcinomas, 19 were metastatic tumors, 03 were hemangiomas and 01 was hepatic adenoma. Doppler sonographic findings were then correlated, case by case, with final diagnosis- either pathologically by USG guided Fine-needle aspiration or by other imaging modalities (e.g., CT scan and RBC liver scan for hepatic hemangioma). The RI value of hepatocellular carcinoma was 0.69±0.096 and in metastatic tumors 0.73±0.079. The results showed no significant difference between the RI of hepatocellular carcinomas and metastatic liver tumors but it was significantly higher than benign lesions (p<0.05). RI of hemangiomas was 0.49±0.64 and in one hepatic adenoma was 0.65. When RI was <0.6 for benign liver tumors and ≥0.6 for malignant tumors we calculated a sensitivity of 89.14%, specificity of 66.7%, accuracy of 85.71% positive predictive value of 97.62% and negative predictive value of 28.57% in differentiating benign and malignant tumors. Thirty four of 46(73.9%) malignant lesions had intratumoral flow and 25% of benign lesions also showed intratumoral flow. The difference of intratumoral flow between malignant and benign lesions was significant (p<0.01). Two of 4 benign lesions (50%) had peritumoral vascularity where 6% of the malignant tumors showed peritumoral vascularity. In conclusion, combined studies of the type of intra-and peri-tumoral flow signals in CDFI and the parameter of RI would be more helpful in the differential diagnosis of benign and malignant liver tumors.