Imaging features of hepatic angiomyolipomas on real-time contrast-enhanced ultrasound

Abstract

The aim of this study was to evaluate the imaging features of hepatic angiomyolipoma (AML) on contrast-enhanced ultrasound (CEUS). The imaging features of 12 pathologically proven hepatic AML lesions in 10 patients who had undergone baseline ultrasound (BUS) and CEUS examinations were evaluated retrospectively. The enhancement extent, pattern and dynamic change, along with the enhancement process, on CEUS were analysed. The diagnostic results of BUS and CEUS before pathological examination were also recorded. The results showed that 75% (9/12) of the AML lesions exhibited mixed echogenicity on BUS and most showed remarkable hyperechogenicity in combination with a hypoechoic or anechoic portion. Arterial flow signals were detected in 75% (9/12) of the lesions on colour Doppler imaging. On CEUS, 66.7% (n = 8) of the 12 lesions exhibited hyperenhancement in the arterial phase, slight hyperenhancement (n = 2) or isoenhancement (n = 6) in the portal phase, and slight hyperenhancement (n = 1) or isoenhancement (n = 7) in the late phase. Three (25%) lesions exhibited hyperenhancement in the arterial phase and hypoenhancement in both portal and late phases. One (8.3%) lesion exhibited hypoenhancement throughout the CEUS process. Before pathological examination with BUS, only 3 (25%) lesions were correctly diagnosed as hepatic AML. Conversely, on CEUS, correct diagnoses were made for 66.8% (8/12) of hepatic AMLs. Therefore, arterial hyperenhancement and subsequent sustained enhancement on CEUS were found in the majority of hepatic AMLs. The combination of BUS and CEUS leads to the correct diagnosis in the majority of hepatic AMLs, and is higher than the success rate achieved by BUS alone.

Figure 1

Hepatic angiomyolipoma in a 42-year-old woman. (a) Baseline ultrasound scan shows a mixed echogenic lesion (arrow) 3.4 cm in diameter in segment 7 of the liver. Hyper- and hypoechoic portions are found in the lesion. (b) In the arterial phase of contrast-enhanced ultrasound, the lesion (arrow) shows homogeneous hyperenhancement 13 s after contrast agent injection. The lesion (arrow) shows isoenhancement in the (c) portal phase (100 s after contrast agent injection) and (d) late phase (130 s after contrast agent injection).

Figure 2

Hepatic angiomyolipoma in a 35-year-old woman. (a) Baseline ultrasound scan shows a mixed echogenic lesion (arrow) 5.3 cm in diameter in segment 7 of the liver. An anechoic portion is found in the lesion. (b) In the arterial phase of contrast-enhanced ultrasound, the lesion (arrow) shows heterogeneous hyperenhancement 11 s after contrast agent injection. The lesion (arrow) shows isoenhancement in the (c) portal phase (44 s after contrast agent injection) and (d) late phase (136 s after contrast agent injection).

Figure 3

Hepatic angiomyolipoma (AML) in a 25-year-old woman. (a) Baseline ultrasound scan shows a mixed echogenic lesion (arrow) 8.8 cm in diameter in segments 3 and 4 of the liver. (b) In the arterial phase of CEUS, the lesion (arrow) shows heterogeneous hyperenhancement 8 s after contrast agent injection. (c) The lesion (arrows) shows isoenhancement in the late phase (180 s after contrast agent injection). (d) Pathological examination confirms the diagnosis of hepatic AML hematoxylin-eosin stain; original magnification: ×100.

Figure 4

Hepatic angiomyolipoma in a 50-year-old woman. (a) Baseline ultrasound scan shows a homogeneously hyperechoic lesion (arrow) 2.9 cm in diameter in segment 5 of the liver. (b) In the arterial phase of contrast-enhanced ultrasound, the lesion (arrow) shows homogeneous hyperenhancement 11 s after contrast agent injection. The lesion (arrows) shows (c) isoenhancement in the portal phase (31 s after contrast agent injection) and (d) hypoenhancement in the late phase (180 s after contrast agent injection).