Evaluation of Hepatocellular Carcinomas and Liver Metastases- How Far can we Go with Diffusion Weighted Imaging?

Objective: We aimed to determine the usefulness of the apparent diffusion coefficient (ADC) values for the differential diagnosis of hepatocellular carcinomas and most common metastatic liver tumors and we aimed to compare the characteristic properties. We also aimed to detect novel lesions on ADC maps before the lesion is clinically and radiologically detected by conventional methods. Materials and Methods: We evaluated characteristic properties, contrast enhancement patterns of liver metastasis of malignancies like adenocancer, renal cell carcinoma (RCC), gastrointestinal stromal tumor (GIST) and hepatocellular carcinoma (HCC) on magnetic resonance imaging (MRI) and diffusion weighted (DW) imaging. ADCs were measured both from the cystic and solid parts of the tumoral lesions. Solid and cystic parts were grouped seperately and compared individually. Results: 48 cases, (60% male and 40% female) with ages ranging between 48 and 81 were involved. 28 of them had liver metastasis and 20 of them had HCC. MRIs between the years 2009 and 2012 were analyzed. Among mean ADC values measured from solid contrast-enhancing parts, values of the HCC group were significantly higher than the metastasis group (p=0.004). Also, in metastasis group consisting of many distinct primaries, there were differences in ADC values. A retrospective analysis for follow-up cases showed that the ADC values of the parencyhma where a lesion will appear on later follow-up images were lower than the adjacent parenchyma. Conclusion: We believe that this method may be useful to detect early metastasis. Studies with larger patient groups could give more significant results which would enable diffusion imaging method to be used in this area.