Part 1: MRI features of focal nodular hyperplasia with an emphasis on hepatobiliary contrast agents

Contrast-enhanced sonographic appearances of two primary hepatic epithelioid angiomyolipomas

Epithelioid hepatic angiomyolipoma (Epi-HAML) is a rare hepatic tumor frequently misdiagnosed as hepatocellular carcinoma (HCC). Unlike conventional angiomyolipoma (AML), Epi-HAML contains minimal amount of adipose tissue, which is a radiological distinguishing feature between AML and HCC. Two patients were referred for management of incidentally found hepatic lesions confirmed to be Epi-HAML on post-resection tissue analysis. CT and MRI findings were suggestive of HCC. Contrast-enhanced ultrasound demonstrated intratumoral shunting, a feeding artery, and early draining hepatic vein. These findings should alert radiologists to the possibility of Epi-HAML. Furthermore, these features may be better assessed by contrast-enhanced ultrasound due to its superior dynamic temporal resolution.

Hepatic disorders associated with exogenous sex steroids: MR imaging findings

OBJECTIVE

To describe the MRI findings of the effects of exogenous sex steroids on the liver.

FINDINGS

Estrogens, progesterone and synthetic testosterone are exogenous sex steroids that may result in a variety of liver diseases, including tumour formation and vascular disorders. These hormones are mainly administered in the form of the oral contraceptive pill (OCP) and anabolic steroids. Both are implicated in hepatic adenoma formation. The HNF-1α-mutated and inflammatory adenoma subgroups are more commonly seen in association with the OCP whereas there is an increased incidence of the β-catenin positive subtype with anabolic steroid use. Furthermore, anabolic steroids are associated with hepatocellular carcinoma resulting from malignant transformation of β-catenin positive adenomas. The oral contraceptive pill may also induce vascular disorders within the liver, some of which are related to the prothrombotic effect of the hormones, such as hepatic and portal vein thrombosis. Other hepatic vascular abnormalities resulting from exogenous sex steroids include veno-occlusive disease and peliosis hepatis.

Enhancements in hepatobiliary imaging: the spectrum of gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid usages in hepatobiliary magnetic resonance imaging

Gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a unique hepatocyte-specific contrast agent approved for clinical use in the United States in 2008. Gd-EOB-DTPA-enhanced MR has shown to improve detection and characterization of hepatic lesions. Gd-EOB-DTPA is now being routinely used in daily clinical practice worldwide. Therefore, it is important for radiologists to be familiar with the potential uses and pitfalls of Gd-EOB-DTPA, which extends beyond the assessment of focal hepatic lesions. The purpose of this article is to review the various usages of Gd-EOB-DTPA in hepatobiliary MR imaging.