The role of diffusion weighted imaging in the evaluation of treatment response of hepatocellular carcinoma after transarterial chemoembolization

Abstract

epatocellular carcinoma (HCC) is one of the most common cancers worldwide, and has a poor prognosis unless treated. Trans-catheter arterial chemoembolization of HCC lesions is a promising treatment option for patients who are not eligible for surgery. Monitoring tumor response after chemoembolization is an increasingly important task in oncologic imaging. Early favorable response indicates effectiveness of therapy while early identification of treatment failure is also critical in patient management as further treatment will be mandatory before disease progression. MRI is a powerful tool in detection of residual tumor viability, quantifying tumour necrosis and detecting complications after TACE using the inherent tissue contrast. Recent advances in the development of functional MR imaging techniques have provided the ability to detect microscopic changes in tumor microenvironment and microstructure that allow better assessment of treatment response. DW MRI in the liver is a relative new and increasingly used imaging technique. It is a promising functional biomarker tool which assesses cellularity of the tissues depending on motion of water molecules (Brownian motion) at the extracellular/extravascular space; the highly cellular tissues show restricted motion of water molecules and the less cellular tissues allow free motion of water molecules.