Magnetic resonance imaging following treatment of advanced hepatocellular carcinoma with sorafenib

Abstract

Hepatocellular carcinomas are highly vascular tumors, showing progressive hypervascularity by the process of neoangiogenesis. Tumor angiogenesis is critical for tumor growth as well as metastatic spread therefore, imaging and quantification of tumor neo-angiogenesis is essential for monitoring response to targeted therapies and predicting disease progression. Sorafenib is a molecular targeting agent used for treating hypervascular tumors. This drug is now the standard of care in treatment of patients with advanced hepatocellular carcinoma. Due to its anti-angiogenic and anti-proliferative actions, imaging findings following treatment with Sorafenib are quite distinct when compared to conventional chemotherapeutic agents. Liver MRI is a widely adopted imaging modality for assessing treatment response in hepatocellular carcinoma and imaging features may reflect pathophysiological changes within the tumor. In this mini-review, we will discuss MRI findings after Sorafenib treatment in hepatocellular carcinoma and review the feasibility of MRI as an early biomarker in differentiating responders from non-responders after treatment with molecular targeting agents.

Keywords: Hepatocellular carcinoma; MRI; Sorafenib; mRECIST.

Figure 1

Tumor signal intensity on T1WI and T2WI after Sorafenib treatment for three months in a 64-year-old man with HCC. (A) T1WI after sorafenib treatment. Note hyperintensity of HCC mass (arrow). This signal intensity is believed to be the result of hemorrhagic necrosis. (B) On T2WI, mass shows hypointensity (arrow) after Sorafenib treatment.

Figure 2

Decreasing tumor enhancement on arterial phase after Sorafenib treatment in a 67-year-old man with HCC. (A) Before Sorafenib treatment, HCC shows arterial enhancement (arrow). (B) Decreased of enhancement of the tumor (arrow) is noted on arterial phase without overall change of tumor size following 12 weeks of Sorafenib therapy.

Figure 3

Changes of DWI and ADC values following Sorafenib treatment in a 57-year-old woman with HCC. (A) On DWI with high b-value of 1,000 before treatment, two high signal tumors are noted in S8 and S4 (arrows). (B) An ADC map before treatment shows low signal intensity lesions at the same area (arrows), which means low ADC values. (C) After 4-month treatment with Sorafenib, signal intensity of HCC (arrows) on DWI with b-value of 1,000 was markedly decreased compared to (A). (D) An ADC map after Sorafenib treatment also shows improved diffusion with higher signal (arrows). (E) Axial, enhanced, portal venous phase image after Sorafenib treatment shows marked necrosis of tumors, which is the cause of increased ADC values and lower signal intensity on DWI.