MRI features of hepatocellular carcinoma related to biologic behavior

Abstract

Imaging studies including magnetic resonance imaging (MRI) play a crucial role in the diagnosis and staging of hepatocellular carcinoma (HCC). Several recent studies reveal a large number of MRI features related to the prognosis of HCC. In this review, we discuss various MRI features of HCC and their implications for the diagnosis and prognosis as imaging biomarkers. As a whole, the favorable MRI findings of HCC are small size, encapsulation, intralesional fat, high apparent diffusion coefficient (ADC) value, and smooth margins or hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI. Unfavorable findings include large size, multifocality, low ADC value, non-smooth margins or hypointensity on hepatobiliary phase images. MRI findings are potential imaging biomarkers in patients with HCC.

Keywords: Hepatocellular carcinoma; Magnetic resonance imaging; Prognosis.

Fig. 1. 55-year-old man with encapsulated progressed HCC.

A. T1-weighted three-dimensional gradient echo image with fat suppression (TR/TE/FA = 2.5 ms/1 ms/11°) in late hepatic arterial phase after administration of gadoxetic acid shows hyperenhancing mass with hyperemia of surrounding liver parenchyma (arrow) in segment 8. B. Mass is hypointense on transitional phase with thin capsule appearance (arrow). Note that relatively high enhancement of background parenchyma on transitional phase may obscure capsular enhancement and reduce confidence of reader. C. Fat-suppressed fast spin echo T2-weighted image shows slight hyperintensity and hypointense capsule (arrow). FA = flip angle, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 2. 76-year-old man with fat-containing HCC.

A, B. Axial dual-echo gradient echo images (TR/TE = 4/1.2 ms, in-phase; 2.4 ms, opposed-phase) show mass in dome of liver. Signal loss (arrow) of mass on opposed-phase (B) compared to in-phase (A) indicates intralesional fat. Presence of intralesional fat permits confident diagnosis of HCC. HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 3. 71-year-old man with HCC showing T1 hyperintensity.

A. Unenhanced fat-saturated T1-weighted three-dimensional gradient echo image with fat suppression (TR/TE/FA = 2.5 ms/0.9 ms/11°) shows hyperintense mass (arrow) in segment 4. B. Mass is barely visible on fat-suppressed fast spin echo T2-weighted imaging due to isointense signal (arrow). FA = flip angle, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 4. 56-year-old man with HCC showing nodule-in-nodule appearance.

A. Pre-contrast T1-weighted three-dimensional GRE image shows hypointense inner nodules within hyperintense outer nodule, consistent with nodule-in-nodule architecture. B. Subtracted arterial phase image shows hyper-enhancement of inner nodules (arrows). C. Inner nodules (arrows) exhibit hyperintensity relative to outer nodule and surrounding liver on fat-suppressed fast spin echo T2-weighted image. Outer nodule is hypointense. GRE = gradient echo, HCC = hepatocellular carcinoma

Fig. 5. 66-year-old man with HCC showing corona enhancement.

A, B. T1-weighted three-dimensional GRE image with fat suppression (TR/TE/FA = 4.5 ms/2.1 ms/15°) in (A) early and (B) late hepatic arterial phase after administration of gadolinium-based contrast agent shows hyper-enhancing mass (arrow) in segment 6. Notice irregular circumferential enhancement (arrow) in liver parenchyma around mass in late hepatic arterial phase. C. Enhancement of perilesional parenchyma fades in portal venous phase. Transient enhancement of perilesional parenchyma is known as corona enhancement. Note capsular appearance of mass (arrow). FA = flip angle, GRE = gradient echo, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 6. 51-year-old man with HCC and microvascular invasion.

A. Gadoxetic acid-enhanced T1-weighted three-dimensional GRE sequence (TR/TE/FA = 3.4 ms/1.7 ms/15°) acquired in late hepatic arterial phase shows heterogeneous mass at segment 8 of liver. B. Transitional phase image at three minutes depicts hypointense mass. C. Margin of mass is non-smooth or lobulated on hepatobiliary phase imaging acquired 20 minutes after injection (arrow). D. Gross pathology photograph of resected specimen reveals confluent, multinodular type HCC. Histopathologic examination proves frequent microvascular invasion. FA = flip angle, GRE = gradient echo, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 7. 64-year-old man with HCC showing hyperintensity in hepatobiliary phase.

A. Gadoxetic acid-enhanced T1-weighted three-dimensional GRE image (TR/TE/FA = 3.4 ms/1.7 ms/15°) in late arterial phase shows exophytic, hyperenhancing mass (arrow) in left posterior liver. B. In hepatobiliary phase, mass is hyperintense with central hypointense areas (arrow). FA = flip angle, GRE = gradient echo, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time

Fig. 8. 51-year-old man with HCC.

A. Hepatobiliary phase image acquired 20 minutes after injection shows hypointense nodule in segment 7 of liver (arrow). B. Nuclear grade III trabecular and pseudoglandular HCC with hepatic cells was confirmed (hematoxylin and eosin staining, × 100). C. Immunoreactivity of keratin 19 was strongly positive (× 100). Cell density ratio was 2.1. HCC = hepatocellular carcinoma

Fig. 9. 63-year-old man with HCC showing restricted diffusion.

A. Gadoxetic acid-enhanced T1-weighted three-dimensional GRE sequence (TR/TE/FA = 3.4 ms/1.7 ms/15°) in late arterial phase shows hyperenhancing mass (arrow) in right lobe of liver. B. Apparent diffusion coefficient map shows hypointensity (arrow) suggesting restricted diffusion. Restricted diffusion is highly suggestive of malignancy, but is not specific for HCC. FA = flip angle, GRE = gradient echo, HCC = hepatocellular carcinoma, TE = echo time, TR = repetition time