Noninvasive imaging of hepatocellular carcinoma: From diagnosis to prognosis

Abstract

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and a major public health problem worldwide. Hepatocarcinogenesis is a complex multistep process at molecular, cellular, and histologic levels with key alterations that can be revealed by noninvasive imaging modalities. Therefore, imaging techniques play pivotal roles in the detection, characterization, staging, surveillance, and prognosis evaluation of HCC. Currently, ultrasound is the first-line imaging modality for screening and surveillance purposes. While based on conclusive enhancement patterns comprising arterial phase hyperenhancement and portal venous and/or delayed phase wash-out, contrast enhanced dynamic computed tomography and magnetic resonance imaging (MRI) are the diagnostic tools for HCC without requirements for histopathologic confirmation. Functional MRI techniques, including diffusion-weighted imaging, MRI with hepatobiliary contrast agents, perfusion imaging, and magnetic resonance elastography, show promise in providing further important information regarding tumor biological behaviors. In addition, evaluation of tumor imaging characteristics, including nodule size, margin, number, vascular invasion, and growth patterns, allows preoperative prediction of tumor microvascular invasion and patient prognosis. Therefore, the aim of this article is to review the current state-of-the-art and recent advances in the comprehensive noninvasive imaging evaluation of HCC. We also provide the basic key concepts of HCC development and an overview of the current practice guidelines.

Keywords: Computed tomography; Diagnosis; Guidelines; Hepatocellular carcinoma; Magnetic resonance imaging; Prognosis; Staging; Surveillance; Ultrasound.

Figure 1

Hepatocellular carcinoma in a 32-year-old male with chronic hepatitis B. Axial dynamic non-enhanced (A), late arterial phase (B), and portal venous phase (C) CT images show the 8.5 cm mass with arterial phase hyperenhancement and portal venous phase wash-out appearance. The capsule is seen as a hyperattenuating ring on portal venous phase (C, white arrow). The hematoxylin-eosin (HE) staining of the mass at 200 × magnification proved it to be Edmonson-Steiner grade II (D).

Figure 2

Hepatocellular carcinoma in 47-year-old male with chronic hepatitis B. 4.7-cm-sized mass in right anterior hepatic section shows hypointensity on unenhanced T1-weighted image (A), hyperenhancement in arterial phase (B), hypointensity relative to the surrounding liver parenchyma in portal venous phase (C), and 20 min hepatobiliary phase (D). An enhancing capsule (white arrow, the peripheral rim of smooth enhancement) in portal venous phase, mosaic architecture, intermediate hyperintensity on T2-weighted images (E), and restricted diffusion (F) are also visible. The mass was confirmed as Edmonson-Steiner grade II at 200 × magnification with hematoxylin-eosin (HE) staining (D).

Figure 3

Hepatocellular carcinoma in a 71-year-old male with recognized cirrhosis. Gd-EOB-DTPA-enhanced MR image demonstrates a 5.3 cm lobulated HCC in right posterior section of liver. The lesion shows peritumor enhancement in arterial phase (B, white arrow) and peritumor hypointense (D, black arrow) in hepatobiliary phase. Capsular disruption and non-smooth tumor margin are present (white triangles) in arterial phase (B) and portal venous phase (C). The lesion was histopathologically proven to be Edmonson-Steiner III grade with hematoxylin-eosin (HE) staining at 200 × magnification (G). Prominent microvascular invasion was detected at 200 × magnification with CD31 immunohistochemical staining (H).