The Role of Diffusion Weighted MR Imaging in Assessment of Hepatic malignancy after Radiofrequency Ablation

Abstract

MRI is a sensitive modality in detection and characterization of hepatic focal lesion. MRI has traditionally been used to evaluate treatment response in malignant liver lesions. However, the assessment of tumor response after certain treatments, such as radiofrequency ablation (RFA) can be difficult. Aim of the Work: To assess role of diffusion weighted MRI in evaluation of treatment response after radiofrequency ablation for hepatic malignancy. Patients and Methods: Ethics committee of the Faculty of Medicine, Ain Shams University, approved this prospective analysis study and cases were supplied by Hospitals of Ain Shams University. 20 cases treated by Radiofrequency ablation for hepatic malignancy were involved in our study. Patients were recruited from Interventional Unit in Radiology Department, Ain Shams University Hospitals. Results: Regarding DWI, our study showed that sensitivity of 83.3% specificity of 85.7% positive predictive value of 71.4%, negative predictive value of 92.3% with diagnostic accuracy of 85%. Our present study showed that the mean ADC of the well ablated lesion was 1.4 X 10-3 mm2/sec and of the residual lesion 0.8 X 10-3 mm2/sec with significant statistical difference between the residual viable tumor and the well ablated lesions. Moreover, it has been shown in our study that the level of ADC may help us to recommend a cut-off value of 1.233×10−3mm2/s. Conclusion: periphery of the ablation zone, which is principally most at risk of tumor residue, should be analyzed separately. Recommendations: Further studies on larger scale of patients are needed to confirm the results obtained by this work. Key words: Diffusion Weighted MRI, hepatic malignancy, radiofrequency ablatio