Published online Jun 8, 2016. doi: 10.4254/wjh.v8.i16.685
Peer-review started: March 2, 2016
First decision: March 22, 2016
Revised: April 7, 2016
Accepted: May 10, 2016
Article in press: May 11, 2016
Published online: June 8, 2016
AIM: To elucidate causes for false negative magnetic resonance imaging (MRI) exams by identifying imaging characteristics that predict viable hepatocellular carcinoma (HCC) in lesions previously treated with locoregional therapy when obvious findings of recurrence are absent.
METHODS: This retrospective institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study included patients who underwent liver transplantation at our center between 1/1/2000 and 12/31/2012 after being treated for HCC with locoregional therapy. All selected patients had a contrast-enhanced MRI after locoregional therapy within 90 d of transplant that was prospectively interpreted as without evidence of residual or recurrent tumor. Retrospectively, 2 radiologists, blinded to clinical and pathological data, independently reviewed the pre-transplant MRIs for 7 imaging features. Liver explant histopathology provided the reference standard, with clinically significant tumor defined as viable tumor ≥ 1.0 cm in maximum dimension. Fisher’s exact test was first performed to identify significant imaging features.
RESULTS: Inclusion criteria selected for 42 patients with 65 treated lesions. Fourteen of 42 patients (33%) and 16 of 65 treated lesions (25%) had clinically significant viable tumor on explant histology. None of the 7 imaging findings examined could reliably and reproducibly determine which treated lesion had viable tumor when the exam had been prospectively read as without evidence of viable HCC.
CONCLUSION: After locoregional therapy some treated lesions that do not demonstrate any MRI evidence of HCC will contain viable tumor. As such even patients with a negative MRI following treatment should receive regular short-term imaging surveillance because some have occult viable tumor. The possibility of occult tumor should be a consideration when contemplating any action which might delay liver transplant.
Core tip: Hepatocellular carcinoma (HCC) is often treated with locoregional therapy such as transarterial chemoembolization as a bridge to transplantation. Detecting residual or recurrent tumor within these treated lesions is challenging and some treated lesions that do not demonstrate any magnetic resonance imaging (MRI) evidence of HCC will contain foci of viable tumor. Regular, short-term imaging surveillance is clinically important for patients being considered for liver transplantation even when prior MRIs have been negative and the possibility of a false negative MRI exam needs to be considered when managing these patients.