Does hepatobiliary phase sequence qualitatively outperform unenhanced T1-weighted imaging in assessment of the ablation margin 24 hours after thermal ablation of hepatocellular carcinomas?
To retrospectively determine whether hepatobiliary phase (HBP) sequence outperforms unenhanced T1-weighted imaging (uT1wI) in distinguishing the ablation margin (AM) from hepatocellular carcinoma (HCC) 24 h after thermoablation.



Ninety-one patients [mean age, 65.7 years; 68 M/23F] with 138 HCCs (>6 months follow-up) underwent pre- and postablation gadoxetate disodium-enhanced MRI. AM showed a hyperintense middle zone (MZ) surrounding central hypo- or hyperintense HCCs on uT1wI, and an intermediate-intense MZ encompassing central hypo- or hyperintense HCCs during HBP. The visible AM was defined as persistent MZ around HCCs, which were demarcated from MZ, or peripherally band encompassing MZ, which were not demarcated from HCC. The indefinite AM was defined as no demarcating HCCs from MZ. The ability to distinguish AM from HCC was classified as visible or indefinite on axial (ax)-uT1wI, ax-HBP, coronal (cor)-HBP, and combined all images. To investigate the AM visibility during HBP, significance of differences upon comparison of ax-uT1wI with combined images was analyzed. Preablation liver-tumor contrast ratio (LTCR) on ax-uT1wI and ax-HBP sequence is compared between the visible and indefinite AM.



The McNemar test demonstrated a significant increase (p < 0.05) in visible AM from ax-uT1wI (60), to ax-HBP (70), cor-HBP (79), and combined images (83). TLCR with visible AM was significantly higher than that with indefinite AM on ax-uT1wI (0.4 vs. 0.2, p = 0.001) and ax-HBP sequence (0.9 vs. 0.6, p = 0.004).



HBP sequence might have higher feasibility to distinguish AM from tumor than ax-uT1wI. The TLCR value in visible AM was higher than that in indefinite AM on both ax-uT1wI and ax-HBP sequences.
Department of Radiology, Showa University Fujigaoka Hospital, Yokohama, Japan. nobuyukitakeyama@gmail.com.|Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA. nobuyukitakeyama@gmail.com.
Nobuyuki
N
Takeyama
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.|Department of Radiology, Chalubhorn Hospital, Bangkok, Thailand.
Sirachat
S
Vidhyarkorn
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.|Department of Radiology, Catholic University of Korea, Seoul, South Korea.
Dong Jin
DJ
Chung
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.|Department of Radiology, Chalubhorn Hospital, Bangkok, Thailand.
Surachate
S
Siripongsakun
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.
Hyun J
HJ
Kim
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.
David S K
DS
Lu
Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Blvd, Los Angeles, CA, 90095, USA.
Steven S
SS
Raman
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome
D003287:Contrast Media
Ablation margin; EOB; Hepatobiliary phase; Hepatocellular carcinoma; MRI