Qualitative and Quantitative Gadoxetic Acid-enhanced MR Imaging Helps Subtype Hepatocellular Adenomas.
OBJECTIVE
To determine which clinical variables and gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging features are associated with histologically proved hepatocellular adenoma (HCA) genotypic subtypes.


METHODS
In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study, clinical information and MR images of 49 histologically proved HCAs from January 2002 to December 2013 (21 patients; mean age, 39 years; age range, 15-59 years) were retrospectively reviewed by two radiologists. Qualitative and quantitative imaging features, including the signal intensity ratio relative to liver in each phase, were studied. HCA tissues were stained with subtype-specific markers and subclassified by a pathologist. Clinical and imaging data were correlated with pathologic findings and compared by using Fisher exact or t test, with a Bonferroni correction for multiple comparisons.


RESULTS
Forty-nine HCAs were subclassified into 14 inflammatory, 20 hepatocyte nuclear factor (HNF)-1α-mutated, one β-catenin-activated, and 14 unclassified lesions. Intralesional steatosis was exclusively seen in HNF-1α-mutated lesions. Marked hyperintensity on T2-weighted images was seen in 12 of 14 (86%) inflammatory lesions compared with four of 21 (19%) HNF-1α-mutated, seven of 14 (50%) unclassified, and zero of one (0%) β-catenin-activated lesion. Two large lesions (one β-catenin-activated and one unclassified) transformed into hepatocellular carcinomas and were the only lesions to enhance with marked heterogeneity. In the hepatobiliary phase, all HCA subtypes were hypoenhancing compared with surrounding liver parenchyma, and they reached their nadir signal intensity by 10 minutes after the administration of contrast material before plateauing. HNF-1α-mutated lesions had the lowest lesion signal intensity ratio of 0.47 ± 0.09, compared with 0.73 ± 0.18 for inflammatory lesions (P = .0004), 0.82 for the β-catenin-activated lesion, and 0.73 ± 0.06 for the unclassified lesion (P = .00002).


CONCLUSIONS
In this study, all HCA subtypes were hypoenhancing at Gd-EOB-DTPA-enhanced MR imaging in the hepatobiliary phase and reached their nadir signal intensity at 10 minutes. HNF-1α-mutated lesions could be distinguished from other subtypes by having the lowest lesion signal intensity ratio.
From the Department of Radiological Sciences (J.R.T., D.S.K.L., S.S.R.) and Department of Pathology and Laboratory Medicine (B.V.N.), David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 10833 Le Conte Ave, 1P-172 CHS, Los Angeles, CA 90095-1732.
Justin R
JR
Tse
From the Department of Radiological Sciences (J.R.T., D.S.K.L., S.S.R.) and Department of Pathology and Laboratory Medicine (B.V.N.), David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 10833 Le Conte Ave, 1P-172 CHS, Los Angeles, CA 90095-1732.
Bita V
BV
Naini
From the Department of Radiological Sciences (J.R.T., D.S.K.L., S.S.R.) and Department of Pathology and Laboratory Medicine (B.V.N.), David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 10833 Le Conte Ave, 1P-172 CHS, Los Angeles, CA 90095-1732.
David S K
DS
Lu
From the Department of Radiological Sciences (J.R.T., D.S.K.L., S.S.R.) and Department of Pathology and Laboratory Medicine (B.V.N.), David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 10833 Le Conte Ave, 1P-172 CHS, Los Angeles, CA 90095-1732.
Steven S
SS
Raman
D000236:Adenoma / Q000473:pathology*; D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA