Diffusion weighted and dynamic contrast enhanced magnetic resonance imaging in assessment of malignant liver tumors after percutaneous radiofrequency ablation

Abstract

Objective: Evaluate the role of Diffusion Weighted (DW-MRI) and Dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI) in assessment of recurrent/residual malignant liver tumors after percutaneous radiofrequency ablation. Patients and methods: This study included 50 patients, 40 males and 10 females. Patients ages ranged from 45 to 80 years with the mean age of 60 years. Patients were referred from Tropical Department for MRI unit after the radiofrequency ablation for malignant liver tumors for assessment of recurrent/residual liver tumors. Results: Thirty-seven patients (74%) had resolved lesions while 13 patients (26%) had recurrent/residual lesions. The border of resolved lesions was smooth but in unresolved lesions was nodular in 11 patients out of 13 (84.6%) and irregular in two patients (15.4%). The measured cut off value between the completely ablated lesions and residual/recurrent lesions was 1.05 × 10−3 mm2/s. The ablated zones can be differentiated from liver parenchyma visually in the DWIs and by means of ADC in all patients. There is no statistical difference in the mean ADC values between the ablated zones of the resolved and unresolved lesions. Conclusion: DW-MRI and DCE-MRI show viable tumor regions and suspected areas in the periphery of the ablated zone could be identified more easily, and analyzed precisely in conjunction with the conventional MRI.

Keywords

• Diffusion Weighted MRI (DW-MRI)
• Dynamic contrast-enhanced Magnetic Resonance Imaging (DCE-MRI)
• Apparent Diffusion Coefficient (ADC)