Liver Apparent Diffusion Coefficient Changes during Telaprevir-Based Therapy for Chronic Hepatitis C

Gd-EOB-DTPA-enhanced MRI-a noninvasive and short-term assessment method for liver necroinflammation after direct-acting antiviral (DAA) therapy in patients with chronic hepatitis C

PURPOSE

To assess liver necroinflammation in HCV patients undergone antiviral therapy by Gd-EOB-DTPA-enhanced MRI with histopathologic analyses as reference.

METHODS

HCV patients were enrolled in this prospective study before antiviral treatment between 09-2016 and 07-2017. Unenhanced MR, Gd-EOB-DTPA-enhanced MR, and liver biopsy were performed before and 24 weeks after treatment of daclatasvir with asunaprevir (DAA). DWI was obtained using a breath-hold single-shot echo planar spin-echo sequence. Twenty minutes after administration of Gd-EOB-DTPA, the relative enhancement (RE) and the contrast enhancement index (CEI) were recorded. Liver necroinflammatory activity grades (G0-18) were categorized on the Ishak Scoring systems. CEI, RE, and DWI of baseline and 24 weeks after treatment were compared by paired t test. Relationship between MR parameters and histologic scores was evaluated by Pearson's correlation. Receiver operating characteristic analysis evaluated the measurements' diagnostic performance. MRI variability between two readers was assessed using the intraclass correlation coefficient.Results RESULTS: A decrease of liver necroinflammatory activity grade (p < 0.0001) was detected in final cohort (n = 21; mean age 44 years; 23 to 67 years; 11 F, 10 M). Statistical results of 42 person-times in 21 patients at baseline and follow-up showed CEI and ADC were significantly different (p = 0.006 and 0.036) across histologic grades of liver necroinflammation. Significant increase of CEI, RE, and ADC (p = 0.0004, 0.0032, 0.0110) 24 weeks after DAA treatment was seen. Additionally, CEI was correlated to necroinflammatory grade (r =  - 0.596, p = 0.006). AUROC for CEI, ADC, and CEI combined with ADC to differentiate patients with none and mild (G0-6) from patients with moderate and severe necroinflammation (G7-18) was 0.834 (95% CI 0.712-0.956, 0.724(95% CI 0.565-0.884) and 0.837(95% CI 0.717-0.956).

CONCLUSION

Gd-EOB-DTPA-enhanced MRI by CEI could be used as a noninvasive imaging biomarker to distinguish grades of necroinflammatory activity in patients with HCV after DAAs therapy at early stage and CEI combined with ADC could get a better diagnostic accuracy.

PET/DW-MRI for evaluating treatment in chronic hepatitis C patients

This feasibility study set out to investigate the use of FDG-PET/DW-MRI in chronic hepatitis C patients to examine changes in local liver inflammation after treatment with direct-acting antivirals (DAA). Twelve patients with chronic hepatitis C were prospectively enrolled, performing FDG-PET/DW-MRI prior to and after DAA treatment. PET/DW-MRI included PET acquisition 60 and 90 min after FDG-injection, DIXON, for attenuation correction, T2- and DW-MRI with 10 b-values between 0-700 s/mm². The following parameters were measured from fusion of 3 volumes of interest (VOIs) placed in the liver parenchyma: Mean standard uptake value after 60 and 90 minutes (SUV_mean60 and SUV_mean90), total Apparent Diffusion Coefficient (ADC), perfusion fraction (PF), pseudo-diffusion (D*) and perfusion-free diffusion (D). We found PET/DW-MRI of chronic hepatitis C patients to be feasible. Patients were cooperative, tolerated the scans well and the image quality was acceptable. A total of 10 patients were available for final analysis. All patients achieved sustained virologic response and normalized alanine-aminotransferase (ALAT) levels after treatment with DAA. Perfusion fraction measured by DW-MRI changed significantly after treatment, from mean 0.21 (± 0.04) to 0.26 (± 0.06), P=0.005 and D* from 0.50 (± 0.13) × 10^-3 s/mm² to 0.62 (± 0.15) × 10^-3 s/mm², P=0.028. All other parameters, including FDG-uptake, was unchanged. These results suggest that liver perfusion is changed shortly after DAA treatment, with no significant change in inflammation. The study concludes that PET/DW-MR is feasible in quantifying perfusion and possibly inflammation in chronic hepatitis C patients and may be used to follow treatment.

Short-term changes observed in multiparametric liver MRI following therapy with direct-acting antivirals in chronic hepatitis C virus patients

Methods

We applied multiparametric MRI to assess changes in liver composition, perfusion and blood flow in 17 patients before direct-acting antiviral (DAA) therapy and after treatment completion (within 12 weeks of last DAA tablet swallowed).

Results

We observed changes in hepatic composition indicated by a reduction in both liver longitudinal relaxation time (T1, 35 ± 4 ms), transverse relaxation time (T2, 2.5 ± 0.8 ms; T2* 3.0 ± 0.7 ms), and liver perfusion (28.1 ± 19.7 ml/100 g/min) which we suggest are linked to reduced pro-inflammatory milieu, including interstitial oedema, within the liver. No changes were observed in liver or spleen blood flow, splenic perfusion, or superior mesenteric artery blood flow.

Conclusion

For the first time, our study has shown that treatment of HCV with DAAs in patients with cirrhosis leads to an acute reduction in liver T1, T2 and T2* and an increase in liver perfusion measured using MR parameters. The ability of MRI to characterise changes in the angio-architecture of patients with cirrhosis after intervention in the short term will enhance our understanding of the natural history of regression of liver disease and potentially influence clinical decision algorithms.

Key Points

• DAAs have revolutionised the treatment of hepatitis C and achieve sustained virological response in over 95% of patients, even with liver cirrhosis.

• Currently available non-invasive measures of liver fibrosis are not accurate after HCV treatment with DAAs, this prospective single-centre study has shown that MRI can sensitively measure changes within the liver, which could reflect the reduction in inflammation with viral clearance.

• The ability of MRI to characterise changes in structural and haemodynamic MRI measures in the liver after intervention will enhance our understanding of the progression/regression of liver disease and could potentially influence clinical decision algorithms.