Distinguishing hypervascular pseudolesions of the liver from hypervascular hepatocellular carcinomas with gadoxetic acid-enhanced MR imaging.
OBJECTIVE
To retrospectively determine findings at gadoxetic acid-enhanced magnetic resonance (MR) imaging in hypervascular pseudolesions that were observed at computed tomography (CT) during hepatic arteriography, with special focus on distinguishing these pseudolesions from hypervascular hepatocellular carcinomas (HCCs).


METHODS
The institute ethics committee deemed study approval unnecessary. The study population comprised 80 patients (55 men, 25 women) with chronic liver disease who underwent CT during hepatic arteriography and arterial portography, gadoxetic acid-enhanced MR imaging, and follow-up dynamic contrast material-enhanced CT. The diagnosis of 104 pseudolesions and 123 HCCs was confirmed by means of histopathologic or multimodality evaluation. Two radiologists assessed the MR imaging findings of HCCs and pseudolesions in consensus, including the signal intensities (SIs) of the lesions on T2-weighted, diffusion-weighted (DW), and contrast-enhanced hepatocyte-phase images. The findings of nodular pseudolesions and HCCs were compared with the Fisher exact test. Additionally, the hepatocyte-phase SI ratio (ratio of lesion SI to liver SI) for HCCs and pseudolesions was compared by means of the Mann-Whitney U test.


RESULTS
There were 62 wedge-shaped, 32 nodular, and 10 linear pseudolesions. On gadoxetic acid-enhanced hepatocyte-phase MR images, 15% of pseudolesions (16 of 104) were hypointense compared with surrounding liver tissue. The mean hepatocyte-phase SI ratio of HCCs (0.65 +/- 0.14 [standard deviation]) was significantly lower (P < .01) than that of the nodular pseudolesions (0.95 +/- 0.11). The optimal cutoff value of hepatocyte-phase SI ratio for distinguishing between HCC and nodular pseudolesion was 0.84. No nodular pseudolesions were visible on DW images.


CONCLUSIONS
Gadoxetic acid-enhanced hepatocyte-phase MR imaging and DW imaging could be used to distinguish hypervascular pseudolesions from hypervascular HCCs; a hepatocyte-phase SI ratio below 0.84 and visibility on DW images were findings specific for HCCs rather than pseudolesions.
Motosugi
Utaroh
U
Department of Radiology, University of Yamanashi, Chuo-shi, Yamanashi, Japan. utaroh-motosugi@nifty.com
Ichikawa
Tomoaki
T
Sou
Hironobu
H
Sano
Katsuhiro
K
Tominaga
Licht
L
Muhi
Ali
A
Araki
Tsutomu
T
D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000175:diagnosis* / Q000473:pathology; D016009:Chi-Square Distribution; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008099:Liver / Q000098:blood supply; D008107:Liver Diseases / Q000175:diagnosis* / Q000473:pathology; D008113:Liver Neoplasms / Q000098:blood supply / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA