MR diffusion-weighted imaging in a case of West Nile virus encephalitis.

Abstract

<b>573</b> <h3><b>Objectives</b></h3> HCC patients meeting Milan criteria (MC) have a good 5-year disease-free survival (DFS). We investigate whether MC assessed by dual-tracer (¹¹C-acetate: ACT &amp; ¹⁸F-FDG) PET/CT could predict 5-year DFS for liver transplant (LT) candidates with HCC. <h3><b>Methods</b></h3> From year 2008, LT candidates with pre/post-operative dual-tracer PET/CT and contrast CT were recruited. They underwent either hepatectomy or LT post imaging evaluation and were followed for 5 years or till HCC recurrence. Preoperative dual-tracer PET/CT and contrast CT were reviewed independently based on the parameters (tumor size and extent, vascular invasion and metastasis) specified by MC with postoperative pathology as the gold standard. For prediction of HCC recurrence within 5 years, KM univariate analysis was performed on the following parameters: age, assessment of MC individually by CT and by dual-tracer PET/CT, primary HCC purely-avid-for-ACT, surgical treatment with hepatectomy or LT. The independent predictors for 5-year DFS were further analyzed by multivariate Cox regression. <h3><b>Results</b></h3> 22 LT candidates (M:18, F:4; mean age=56±9.3y; 21 HBV, 1 HCV) were included (lesion size:1.4~7 cm, ≤3 lesions/patient). Pathological assessment classified 14 patients within and 8 beyond MC. The assessment of MC by dual-tracer PET/CT was significantly better than contrast CT in correlation with pathology (correlation=0.904 vs 0.174). 9/22 patients had recurrent HCC within 5 years. Univariate analysis identified 2 significant predictors for a better 5-year DFS: 1. assessed by dual-tracer PET/CT as meeting MC (median DFS&gt;5 y vs 22 mo for those beyond MC); 2. primary HCC being purely ACT-avid (median DFS&gt;5 y vs 26 mo for those with ¹⁸F-FDG-avidity, both P&lt;0.05). Both parameters were also independent predictors for 5-year DFS by multivariate analysis. <h3><b>Conclusions</b></h3> Preoperative dual-tracer PET/CT is more accurate than contrast CT for evaluation of MC for LT candidates. HCC patients satisfying MC based on dual-tracer PET/CT assessment and with pure ACT-avidity have a better 5-year DFS.