Prognostic Value Of Multiparametric MR Imaging In Neuroendocrine Liver Metastases Treated With Transarterial Chemoembolization

Part 1.Prognostic value of baseline multiparametric MR imaging whole tumor histogram analysis in neuroendocrine liver metastases treated with transarterial chemoembolizationObjectives: To determine whether baseline multiparametric MR imaging whole tumor histogram analysis can predict overall survival(OS)and hepatic progression-free survival(HPFS)in patients with neuroendocrine liver metastases(NELMs)treated with transarterial chemoembolization(TACE).Methods: This retrospective study included 84 NELMs patients treated with TACE.All patients underwent multiparmetric MRI scans including unenhanced and contrast-enhanced T1 weighted imaging and diffusion weighted imaging within 6 weeks before TACE.Tumor volume and whole tumor histogram analysis of arterial enhancement(AE),venous enhancement(VE)and apparent diffusion coefficient(ADC)were performed on baseline MR imaging using proprietary software MRArithmetric and Multiparametric Analysis.Demographic and clinical data including age,gender,tumor type,tumor differentiation,plasma chromogranin A level,ECOG performance score,the presence or absence of extrahepatic metastases,treatments and follow-up were recorded.A maximum of one,two and five index lesions were selected in each patient.OS was the primary endpoint and HPFS was the secondary endpoint.Prognostic values of volumetric multiparametric MR parameters for predicting OS and HPFS considering a maximum of one,two and five index lesions were assessed.Results: Prognostic values of multiparametric MRI whole tumor histogram analysis parameters for predicting OS and HPFS were similar regardless of maximum number of index lesions.Multivariate survival analysis showed that baseline dominant tumor volume≥73 cm3,whole tumor mean AE≥45% and mean VE≥73% were independent prognostic factors for OS(HR: 2.73;95%CI: 1.45,5.15;HR: 0.32;95%CI: 0.17,0.63;HR: 0.35;95%CI: 0.17,0.72,respectively)and HPFS(HR: 2.30,95%CI: 1.38,3.84;HR: 0.46,95%CI: 0.25,0.84;HR: 0.36,95%CI: 0.19,0.57,respectively).OS and HPFS were similar in patients with low and high whole tumor mean ADC.Conclusion: Baseline multiparametric MR imaging whole tumor histogram analysis may act as prognostic factors for OS and HPFS in NELMs patients treated with TACE.Part 2.Prognostic value of visually assessed semi-quantitative HTB using MRI in neuroendocrine liver metastases treated with transarterial chemoembolizationObjectives: To evaluate the accuracy and reproducibility of semi-quantitative visual assessment of hepatic tumor burden(HTB)on MRI and to investigate its prognostic value in predicting overall survival(OS)in neuroendocrine liver metastases(NELMs)treated with transarterial chemoembolization(TACE).Methods: Three independent readers blinded to the quantitative HTB measurement reviewed baseline MRI in 111 NELMs patients treated with TACE.Readers visually assessed and semi-quantitatively categorized HTB as≤10%,11-25%,26-50% and >50% according to European Neuroendocrine Tumor Society(ENETS)guidelines.Quantitative HTB measured by manual segmentation was used as the reference standard.Agreements between quantitative and semi-quantitative visual measurement of HTB,as well as intra-and inter-reader reproducibility were evaluated using weighted kappa coefficient and intraclass correlation coefficient(ICC).Survival analysis included Kaplan-Meier curves and COX regression.Harrell C-index was calculated to evaluate the prognostic value of semi-quantitative HTB for predicting OS.Results: According to quantitative HTB,41,29,25 and 16 patients were categorized into ≤10%,11-25%,26-50% and >50% groups,respectively.Agreements between quantitative and semi-quantitative visual measurement of HTB by each reader(weighted kappa(95% confidence interval(95% CI)),0.82(0.75,0.88)-0.96(0.92,0.99)),intra-reader agreement(weighted kappa(95% CI),0.95(0.91,0.98))and inter-reader agreements(weighted kappa(95% CI),0.84(0.77,0.90)-0.91(0.86,0.95);ICC(95% CI),0.98(0.97,0.99))were at least substantial to almost perfect.Semi-quantitative HTB was an independent prognostic factor in NELMs treated with TACE(multivariate COX regression,p <0.001),with prognostic value comparable to that of quantitative HTB(Harrell C-index,0.735 for both semi-quantitative and quantitative HTB in multivariate regression).Conclusion: Semi-quantitative visual assessment of HTB using MRI is accurate and reproducible,and could reliably predict OS in NELMs treated with TACE.