Necro-inflammatory activity grading in chronic viral hepatitis with three-dimensional multifrequency MR elastography

Visco-Elastic Parameters at Three-Dimensional MR Elastography for Diagnosing Non-Alcoholic Steatohepatitis and Substantial Fibrosis in Mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasing worldwide and is a growing cause of liver cirrhosis and cancer. The performance of the magnetic resonance elastography (MRE) visco-elastic parameters in diagnosing progressive forms of NAFLD, including nonalcoholic steatohepatitis (NASH) and substantial fibrosis (F ≥ 2), needs to be clarified.

PURPOSE

To assess the value of three-dimensional MRE visco-elastic parameters as markers of NASH and substantial fibrosis in mice with NAFLD.

STUDY TYPE

Prospective.

ANIMAL MODEL

Two mouse models of NAFLD were induced by feeding with high fat diet or high fat, choline-deficient, amino acid-defined diet.

FIELD STRENGTH/SEQUENCE

7T/multi-slice multi-echo spin-echo MRE at 400 Hz with motion encoding in the three spatial directions.

ASSESSMENT

Hepatic storage and loss moduli were calculated. Histological analysis was based on the NASH Clinical Research Network criteria.

STATISTICAL TESTS

Mann-Whitney, Kruskal-Wallis tests, Spearman rank correlations and multiple regressions were used. Diagnostic performance was assessed with areas under the receiver operating characteristic curves (AUCs). P value <0.05 was considered significant.

RESULTS

Among the 59 mice with NAFLD, 21 had NASH and 20 had substantial fibrosis (including 8 mice without and 12 mice with NASH). The storage and loss moduli had similar moderate accuracy for diagnosing NASH with AUCs of 0.67 and 0.66, respectively. For diagnosing substantial fibrosis, the AUC of the storage modulus was 0.73 and the AUC of the loss modulus was 0.81, indicating good diagnostic performance. Using Spearman correlations, histological fibrosis, inflammation and steatosis, but not ballooning, were significantly correlated with the visco-elastic parameters. Using multiple regression, fibrosis was the only histological feature independently associated with the visco-elastic parameters.

CONCLUSION

MRE in mice with NAFLD suggests that the storage and loss moduli have good diagnostic performance for detecting progressive NAFLD defined as substantial fibrosis rather than NASH.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY STAGE: 2.

Predictive value of liver and spleen stiffness measurement based on two-dimensional shear wave elastography for the portal vein pressure in patients with compensatory viral cirrhosis

Objective

This study aimed to explore the predictive value of liver and spleen stiffness measurement based on two-dimensional shear wave elastography for the portal vein pressure in patients with compensatory viral cirrhosis.

Methods

From January 2017 to August 2019, 107 patients with compensatory viral cirrhosis and 76 patients with viral hepatitis were enrolled as cirrhosis group and hepatitis group, respectively. Patient data were obtained during admission, and this study was a review and analysis of patient data. Liver stiffness measurement (LSM), spleen stiffness measurement (SSM), portal vein diameter and spleen thickness were compared between the two groups, and their diagnostic value for compensatory viral cirrhosis was analyzed. According to the hepatic vein pressure, the cirrhosis group patients were divided into non-hypertensive group (no portal hypertension, hepatic venous pressure gradient (HVPG) < 5 mmHg), mild group (mild portal hypertension, 5 mmHg ≤ HVPG ≤ 10 mmHg) and severe group (clinically significant portal hypertension group, HVPG > 10 mmHg). LSM, SSM, portal vein diameter and spleen thickness of the three groups were compared, and the correlation between SSM and hepatic vein pressure was analyzed.

Results

LSM, SSM, portal vein diameter and spleen thickness in the cirrhosis group were higher than those in hepatitis group (all P < 0.05). The area under the curve (AUC) of combined detection was larger than that of LSM, SSM and spleen thickness detection alone in liver cirrhosis diagnosis (all P < 0.05). LSM, SSM, portal vein diameter and spleen thickness increased with the increase of hepatic vein pressure in patients with liver cirrhosis (all P < 0.05). LSM, SSM, portal vein diameter and spleen thickness were all positively correlated with hepatic vein pressure (P < 0.05). ROC curve showed that AUC of combined detection was greater than that of LSM, SSM, portal vein diameter and spleen thickness alone detection in the diagnosis of clinically significant portal hypertension (all P < 0.05). The increase of LSM, SSM, portal vein diameter and spleen thickness were the influencing factors for hepatic vein pressure rising (all P < 0.05).

Conclusion

There was an increase of LSM and SSM in patients with compensatory viral cirrhosis, which were positively correlated with hepatic venous pressure, and combined index detection has diagnostic and predictive value for the change of portal venous pressure.

Preclinical Three-Dimensional Vibrational Shear Wave Elastography for Mapping of Tumour Biomechanical Properties In Vivo

Preclinical investigation of the biomechanical properties of tissues and their treatment-induced changes are essential to support drug-discovery, clinical translation of biomarkers of treatment response, and studies of mechanobiology. Here we describe the first use of preclinical 3D elastography to map the shear wave speed (cs), which is related to tissue stiffness, in vivo and demonstrate the ability of our novel 3D vibrational shear wave elastography (3D-VSWE) system to detect tumour response to a therapeutic challenge. We investigate the use of one or two vibrational sources at vibrational frequencies of 700, 1000 and 1200 Hz. The within-subject coefficients of variation of our system were found to be excellent for 700 and 1000 Hz and 5.4 and 6.2%, respectively. The relative change in cs measured with our 3D-VSWE upon treatment with an anti-vascular therapy ZD6126 in two tumour xenografts reflected changes in tumour necrosis. U-87 MG drug vs vehicle: Δcs = −24.7 ± 2.5 % vs 7.5 ± 7.1%, (p = 0.002) and MDA-MB-231 drug vs vehicle: Δcs = −12.3 ± 2.7 % vs 4.5 ± 4.7%, (p = 0.02). Our system enables rapid (<5 min were required for a scan length of 15 mm and three vibrational frequencies) 3D mapping of quantitative tumour viscoelastic properties in vivo, allowing exploration of regional heterogeneity within tumours and speedy recovery of animals from anaesthesia so that longitudinal studies (e.g., during tumour growth or following treatment) may be conducted frequently.