Abstract No. 54: Anatomic and Functional MRI Changes in Hepatocellular Carcinoma during and after Chemoembolization

Abstract

Anatomic MRI assessment of hepatocellular carcinoma (HCC) response to transcatheter arterial chemoembolization (TACE) may need 3 months before detecting size changes. While functional changes in water diffusion may be seen as soon as 1 week after TACE, it is unclear if changes occur immediately after therapy and if it may be used to predict future anatomic response. Integrated MR/x-ray DSA suites offer the ability to assess intra-procedural changes using diffusion weighted MRI (DWI). We tested the hypothesis that apparent diffusion coefficient (ADC) changes on DWI during and after TACE could be used to predict anatomic tumor size change at 3 months after treatment. 21 HCC patients (mean age 57 yr ± 11) underwent TACE using MR-IR monitoring. Anatomic 1.5T MRI (Gd-enhanced T1-weighted GRE) and DWI (single-shot spin-echo EPI; b values=0, 500sec/mm2) were performed during TACE to give immediate pre- and post TACE measurements. Similar MRI follow-up was done at 1 and 3 months post TACE. Tumor size (WHO and EASL criteria) and ADC values were measured. ADC and tumor size between time intervals were compared using a paired two-tailed t-test. We compared percent change (PC) in ADC to tumor size (minimum > 5% change in size) using a paired t-test (α=0.05). Mean ADC values, WHO & EASL measurements, and p values are shown in Table.Tabled 1Table of results.Pre ADC (x10-2 mm2/sec)Post ADC (x10-2 mm2/sec)1 Month ADC (x10-2 mm2/sec)3 Month ADC (x10-2 mm2/sec)Mean157.69158.04193.57163.12P Value.998.043.364Pre TACE WHO(cm2)Post TACE WHO(cm2)1 Month WHO(cm2)3 Month WHO(cm2)Mean17.8917.3813.5115.02P Value0.2150.3540.860Pre TACE EASL(cm2)Post TACE EASL(cm2)1 Month EASL(cm2)3 Month EASL(cm2)Mean15.9614.829.629.79P Value0.0250.0210.042WHO PC at 3 MonthADC PC at 1 MonthADC PC Post TACEMean-48.06%34.84%-22.96%P value0.0270.356 Open table in a new tab Immediate functional changes in water mobility do not occur in HCC during TACE, but they do occur at 1 month follow-up. These 1-month functional MRI changes can be used to predict future anatomic tumor response at 3 months.