Imaging of HCC-Current State of the Art

Abstract

Early diagnosis of hepatocellular carcinoma (HCC) is crucial for optimizing treatment outcome. Ongoing advances are being made in imaging of HCC regarding detection, grading, staging, and also treatment monitoring. This review gives an overview of the current international guidelines for diagnosing HCC and their discrepancies as well as critically summarizes the role of magnetic resonance imaging (MRI) and computed tomography (CT) techniques for imaging in HCC. The diagnostic performance of MRI with nonspecific and hepatobililiary contrast agents and the role of functional imaging with diffusion-weighted imaging will be discussed. On the other hand, CT as a fast, cheap and easily accessible imaging modality plays a major role in the clinical routine work-up of HCC. Technical advances in CT, such as dual energy CT and volume perfusion CT, are currently being explored for improving detection, characterization and staging of HCC with promising results. Cone beam CT can provide a three-dimensional analysis of the liver with tumor and vessel characterization comparable to cross-sectional imaging so that this technique is gaining an increasing role in the peri-procedural imaging of HCC treated with interventional techniques.

Keywords: computed tomography; contrast media; diffusion-weighted imaging; dual-energy computed tomography; dynamic contrast-enhanced magnetic resonance imaging; guidelines; hepatocellular carcinoma; hepatocyte specific contrast media; magnetic resonance imaging; volume perfusion computed tomography.

Figure 1

Radiological hallmarks of hepatocellular carcinoma (HCC). Typical vascular pattern of HCC as observed in a 67-year old patient with histology proven HCC. Liver lesion in the right hepatic lobe observed in a cirrhotic patient. The lesion is presenting a typical HCC vascular pattern with arterial hyperenhancement (left images) and venous wash-out (right images) visible both in magnetic resonance imaging (MRI) (upper row) and computed tomography (CT) (lower row).

Figure 2

Diagnostic algorithm according to the (European Association for the study of the liver (EASLD) for the evaluation of hepatic nodules in patients at risk for HCC. * typical enhancement: arterial hyperenhancement, portal venous/late phase wash-out.

Figure 3

A 47-year old female patient with a large haemangioma in the left liver lobe. Typical image series obtained using hepatocyte specific contrast media is shown. A large lesion is visible in the left liver lobe which presents hypointense in T1, markedly hyperintense in T2 with bright signal in the ADC map. In the contrast-enhanced dynamic series performed after intravenous application of a liver specific contrast agent, the lesions shows centripetal enhancement. In the hepatobiliary phase obtained 20 min after contrast injection, the lesion is hypointense in contrast to the hyperintense liver parenchyma. Haemangiomas do not show the typical pooling appearance in the hepatobiliary phase. Diagnostic confidence can be increased when considering the typically bright signal in T2 and the high ADC values. T1: T1-weighted image; T2: T2-weighted image with fat saturation; ADC: apparent diffusion coefficient map; art: contrast-enhanced image in the arterial phase; pv: contrast-enhanced image in the portal venous phase; hb: contrast-enhanced image in the hepatobiliary phase.

Figure 4

A 47-year old female patient with focal nodular hyperplasia (FNH). Image series obtained before and after administration of hepatocyte specific contrast media is shown. In the right liver, lobe multiple lesions are visible. Lesions present slightly hypointense in T1 and slightly hyperintense in T2. In the contrast-enhanced study using liver specific contrast agent, the lesions show early arterial enhancement which persists in the portal venous phase. In the hepatobiliary phase obtained 20 min after contrast injection, the lesions show persistent contrast enhancement of varying intensity which is most pronounced in the periphery of the largest lesion in segment 6. T1: T1-weighted image in opposed phase; T2: T2-weighted image with fat saturation; T1 fs: T1-weighted image with fat saturation; art: contrast-enhanced image in the arterial phase; pv: contrast-enhanced image in the portal venous phase; hb: contrast-enhanced image in the hepatobiliary phase.

Figure 5

A 24-year old female patient with a large mass in the right liver lobe. Image series obtained before and after administration of hepatocyte specific contrast media is shown. In the right hepatic lobe, a large lesion with heterogeneous signal is visible. Multiple T1-hyperintense structures are present in the lesion representing intralesional hemorrhage. In the contrast-enhanced series, marked arterial enhancement is seen in the solid parts of the lesion. In the hepatobiliary phase, intralesional hemorrhage remains as bright spots while the solid tumor parts in the periphery show moderately hypointense signal in contrast to the brightly enhancing liver parenchyma. The lesion was resected and was proven to be a hepatic adenoma. T1: T1-weighted image opposed phase; T2 fs: T2-weighted image with fat saturation; T1 fs: T1-weighted image with fat saturation; art: contrast-enhanced image in the arterial phase; pv: contrast-enhanced image in the portal venous phase; hb: contrast-enhanced image in the hepatobiliary phase.

Figure 6

Typical MR imaging features of HCC using hepatocyte specific contrast media. Axial MR images of the liver obtained after intravenous administration of a hepatocyte specific contrast agent in arterial (left) and hepatobiliary (right) phase obtained 20 min after i.v. contrast application. In segment 6, a hypervascular lesion is observed. In the hepatobiliary phase image, the lesion is hypointense in relation to the surrounding liver due to reduced uptake of contrast agent due to loss of functioning hepatocytes in the dedifferentiated HCC lesion.

Figure 7

Diffusion-weighted imaging in a 67-year old patient with histology proven HCC. Liver lesion in the right hepatic lobe observed in a cirrhotic patient (same patient as in Figure 1). The HCC lesion is presenting with high signal in the diffusion-weighted image (left) with high b-value (b = 800 s/mm²) and shows reduced ADC when compared to the surrounding liver parenchyma (right).

Figure 8

Cone beam computed tomography (CB CT) gained during transarterial chemoembolization (TACE). Coronal multiplanar reconstruction (A), coronal maximum intensity projection; (B) and volume rendering technique; (C) are presented. The tumor volume is marked by the big white arrow and the tumor feeding vessel is marked by a smaller white arrow. The asterisk marks the catheter position in the common hepatic artery.

Figure 9

Parenchymal blood volume (PBV) in a HCC lesion before (A) and after (B) drug eluting bead (DEB) TACE. The tumor volume is marked by the white arrow in all three images; (B) shows disappearance of PBV after treatment; (C) demonstrates contrast media staining after delivery of beads typically for DEB TACE.