The Role of Diffusion Weighted Magnetic Resonance Imaging and Subtraction Magnetic Resonance imaging in Assessing Treatment Response of Hepatocellular Carcinoma After Transarterial Chemoembolization

Abstract

Background: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and has a poor prognosis unless treated. Ablative therapies are promising treatment options for patients who are not eligible for surgery. Monitoring tumor response after transarterial chemoemolization (TACE) procedure is an important task in oncologic imaging. Early favorable response indicates effectiveness of therapy, while early treatment failure identification is also critical in patient management. In such cases further re-treatment will be mandatory. Aim of work: The aim of this study is to evaluate the efficiency of both diffusion weighted images and subtracted dynamic MRI technique in the detection of residual/ recurrent disease after TACE ablation of non resectable hepatocellular carcinoma (HCC) lesions. Accurate judgment of tumor viability will help diagnose the need for further treatment sessions. Patients and Methods: This study included 32 patients having 54 HCC lesions that underwent transarterial chemoembolization procedure over a period of 6 months (2017- 2018) were followed up 1-1.5 months by dynamic MRI. 12 patients of which underwent a second follow up within 3-4 months. Patients’ ages ranged between 59 to 73 years (mean age 53.1); 26 patients were males and 6 were females. All patients had liver cirrhosis related to chronic viral hepatitis. Results: In 1ry response and follow up findings post TACE, where good response was defied as disappearance of any intra tumoral arterial enhancement in treated lesions, residual disease was defined as at least 30% reduction in the sum of diameters of the viable enhancing lesion in the arterial phase, no response was less than 30% reduction in the enhancing lesion diameters. Progressive disease was defined as 20% increase in the sum of diameters of the enhancing lesions in comparison to the target lesion diameter at the start of treatment. Conclusion: MRI is a powerful tool in detection of residual tumor viability, quantifying tumor necrosis and detecting complications after TACE. Imaging protocol should include dynamic study combined with post processing subtraction images for better tissue characterization.