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Imaging features of hepatic hemangiomas with Pseudo washout sign on Gd-EOB-DTPA enhanced MRI1Department of Radiology，The Third Hospital Affiliated of Nantong University, Nantong, China
Synopsis
Gadoxetate disodium（Gd-EOB-DTPA）is a novel hepatobiliary contrast agent with characteristics of conventional contrast agents and can also be taken up by liver cells specifically, which is beneficial in characterization of focal liver lesions. In clinical practice, some small hemangiomas usually show low signal in transitional phase of Gd-EOB-DTPA enhanced MRI, defined as Pseudo washout sign（PWS）, which can be easily misdiagnosed as hepatocellular carcinoma (HCC) if diagnostic physician do not have sufficient experience. Our study intended to improve the understanding of hepatic hemangiomas with atypical imaging features by summarizing the imaging features of hepatic hemangioma with PWS in Gd-EOB-DTPA-enhanced MRI.
Introduction
Gadoxetate disodium (Gd-EOB-DTPA) is a dual-function novel MR contrast agent with both characteristics of traditional contrast agent and hepatobiliary contrast agent, which improves diagnostic accuracy and sensitivity of hepatocellular carcinoma ( HCC) [1]. Some small hemangiomas usually show low signal in transitional phase of Gd-EOB-DTPA enhanced MRI, defined as Pseudo washout sign (PWS), which is difficult to diagnose when HCC and hepatic hemangiomas coexisting. Our study would compare imaging features of hepatic hemangiomas with and without PWS in Gd-EOB-DTPA enhance MRI, and to summarize imaging features of hepatic hemangiomas with PWS.Methods
From Jan 2012 to May 2017, we evaluated the imaging information of 62 patients with 83 hemangiomas, investing the enhancement patterns (nodular enhancement, diffuse homogenous enhancement and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, PWS during the transition phase)(fig.1~6) and visually assessing the intensity of contrast enhancement (in relation to that of the liver parenchyma using a four-point scale during each phase : grade 4, clearly higher; grade 3, moderately higher; grade 2, equal; grade 1, lower) of the lesions. Chi-square test and Mann-Whitney U test were performed to compare the hemangiomas with and without PWS .Result
Among 83 hepatic hemangiomas, 16.9％(14) were characterized with PWS, which were significantly smaller than those without PWS(P＜0.05); more frequently diffuse enhancement, less nodular and fill-in enhancement(P＜0.05) in hemangiomas with PWS than those without; visually determined grades in hemangiomas with PWS were significantly lower than those without during portal venous phase(P＜0.05).Conclusion and discussion
The typical enhancement patterns of hemangiomas are nodular enhancement in arterial phase, fill-in enhancement in portal vein phase, delayed enhancement in transition phase. However, Tateyama[2] reported that 48% hepatic hemangiomas showed PWS enhancement after Gd-EOB-DTPA enhanced MRI examination. Our study showed that hepatic hemangiomas with the characterization of being small, showing diffuse enhancement during arterial phase or lower visually determined grades during portal venous phase tend to show PWS during the transition phase on Gd-EOB-DTPA enhanced MRI. If necessary, diagnostic physician should combine these characterizations with T2WI sequence, CT and conventional contrast medium enhanced MR to avoid misdiagnosis.Acknowledgements
No acknowledgement found.References
[1] Baek CK,Choi JY,Kim KA,et al.Hepatocellular carcinoma in patients with chronic liver disease: a comparison of gadoxetic acid-enhanced MRI and multiphasic MDCT[J].Clinical radiology, 2012, 67(2):148-156.
[2] Tateyama A,Fukukura Y,Takumi K,et al.Hepatic Hemangiomas: Factors Associated with Pseudo Washout Sign on Gd-EOB-DTPA-enhanced MR Imaging[J]. Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine,2016, 15(1): 73-82.
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