Evaluation of the Resistance Index in Differential Diagnosis of Small Liver Neoplasms by Color Doppler Ultrasonography

Objective To investigate the diagnostic value of the resistance index (RI) in color Doppler ultrasonography for small liver neoplasms. Methods Two hundred and ninty seven patients with 304 hepatic solid lesions which had a diameter smaller than 30mm were studied with color Doppler flow imaging (CDFI) and pulsed Doppler,including 234 malignant cases (218 primary malignant liver tumors,and 16 metastatic liver tumors ),67 benign lesions.All of them were confirmed by operation and pathology. Results The detection rate of arterial flow in malignant tumors was 88.2%,while it was 58.2% in benign lesions,which was significantly different.With Doppler spectrum analysis,resistance index in primary malignant tumors was 0.77±0.12,in metastatic tumors that was 0.71±0.07,whereas the average RI in benign lesions was below 0.6.The difference was significant.This difference was correlated with tissue structure of histopathology. Conclusion If arterial flow was detected with CDFI,RI≥0.6 was regarded as a criterion of the malignant tumor,the sensitivity was 96.2%,specificity was 88.1%,accuracy was 94.2% while RI0.6,was regarded as an index of benign disorders of liver.