Magnetic resonance imaging features of hepatocellular adenoma

Jiaman WU; Xiaohui HUANG; Jianyu XIANG

ABSTRACT

Objective:

To study the magnetic resonance imaging (MRI) features of hepatocellular adenomas (HCA).

Methods:

The MRI images of 36 patients who were diagnosed to have HCA by pathology at Wenzhou Chinese Medicine Hospital and Wenzhou People’s Hospital between January 2013 to May 2018 were reviewed retrospectively. There were 14 males and 22 females, age ranged from 27 to 85 (46±4) years. The location, size, morphology, signal intensity and enhancement modes of tumors were observed.

Results:

For plain scans of MRI among 36 patients, the lesions of 10, 23 and 3 patients respectively were located in the left, right and both left and right hemilivers. The lesions of 15, 12 and 9 patients were round-like, oval-like and nodular shape, respectively. The maximum diameter ranged from 2.0 to 11.0 (4.8±2.6) cm. T 1 weighted imaging (T 1WI) of 21, 11, and 4 patients showed low signal, iso-signal, and slightly high signal, respectively. T 2 weighted imaging (T 2WI ) of 33, and 3 patients showed high, or slightly high signal and iso-signal, respectively. T 2WI on fat-suppression of 32 and 4 patients showed high, or slightly high signal and iso-signal, respectively. Diffusion weighted imaging (DWI) of 24, and 12 patients showed high or slightly high signal and iso-signal, respectively. T 2WI of 11 patients showed a high signal ring while the center had a relatively low signal, called the " atoll" sign. Of the 36 patients, 30 had a peritumoral low-signal pseudo-envelope, 11 had intratumoral necrosis, and 8 had intratumoral hemorrhage. On dynamic contrast enhancement scanning the arterial phase of 22 and 14 patients showed uniform enhancement and uneven enhancement, respectively, while 16 lesions showed significant enhancement, in 15 patients moderate enhancement, and in 5 patients mild enhancement. In the portal venous phase of 7, 12 and 17 patients, the tumor signals were higher, equal and lower than the liver parenchyma signal, respectively. In the delayed phase of 1, 18 and 17 patients, the tumor signals were higher, equal and lower than the liver parenchyma, respectively. In the portal vein and delayed phase, 30 and 6 patients, the pseudocapsules showed mildly enhanced and no enhancement, respectively.

Conclusion:

HCA is mostly round or oval, T 1WI low signal, T 2WI, T 2WI fat suppression and DWI showed high or slightly high signal. Significant enhancement of arterial phase enhancement, mild enhancement of portal phase and delayed phase, a " atoll sign" and a peritumoral pseudocapsule are helpful for diagnosis.