Ultrasound-guided transient elastography and two-dimensional shear wave elastography for assessment of liver fibrosis: emphasis on technical success and reliable measurements

Palm-Sized Wireless Transient Elastography System with Real-Time B-Mode Ultrasound Imaging Guidance: Toward Point-of-Care Liver Fibrosis Assessment

Transient elastography (TE), recommended by the WHO, is an established method for characterizing liver fibrosis via liver stiffness measurement (LSM). However, technical barriers remain towards point-of-care application, as conventional TE requires wired connections, possesses a bulky size, and lacks adequate imaging guidance for precise liver localization. In this work, we report the design, phantom validation, and clinical evaluation of a palm-sized TE system that enables simultaneous B-mode imaging and LSM. The performance of this system was validated experimentally using tissue-equivalent reference phantoms (1.45-75 kPa). Comparative studies against other liver elastography techniques, including conventional TE and two-dimensional shear wave elastography (2D-SWE), were performed to evaluate its reliability and validity in adults with various chronic liver diseases. Intra- and inter-operator reliability of LSM were established by an elastography expert and a novice. A good agreement was observed between the Young's modulus reported by the phantom manufacturer and this system (bias: 1.1-8.6%). Among 121 patients, liver stiffness measured by this system and conventional TE were highly correlated (r = 0.975) and strongly agreed with each other (mean difference: -0.77 kPa). Inter-correlation of this system with conventional TE and 2D-SWE was observed. Excellent-to-good operator reliability was demonstrated in 60 patients (ICCs: 0.824-0.913). We demonstrated the feasibility of employing a fully integrated phased array probe for reliable and valid LSM, guided by real-time B-mode imaging of liver anatomy. This system represents the first technical advancement toward point-of-care liver fibrosis assessment. Its small footprint, along with B-mode guidance capability, improves examination efficiency and scales up screening for liver fibrosis.

Non-Invasive Measurement of Hepatic Fibrosis by Transient Elastography: A Narrative Review

Transient elastography by FibroScan® (Echosens, Paris, France) is a non-invasive method that can provide a reliable measurement of liver fibrosis through the evaluation of liver stiffness. Despite its limitations and risks, liver biopsy has thus far been the only procedure able to provide data to quantify fibrosis. Scientific evidence and clinical practice have made it possible to use FibroScan® in the diagnostic work-up of several liver diseases to monitor patients' long-term treatment response and for complication prevention. For these reasons, this procedure is widely used in clinical practice and is still being investigated for further applications. The aim of this narrative review is to provide a comprehensive overview of the main applications of transient elastography in the current clinical practice.

Liver Involvement in Patients with Systemic Sclerosis: Role of Transient Elastography in the Assessment of Hepatic Fibrosis and Steatosis

Background Systemic sclerosis (SSc) is a rare, multisystemic disorder of connective tissue characterized by widespread inflammation, vascular abnormalities, and both skin and visceral organ fibrosis. Tissue fibrosis is the final phase of a complex biological process of immune activation and vascular damage. Objectives The aim of the study was to assess hepatic fibrosis and steatosis in SSc patients by transient elastography (TE). Methods Fifty-nine SSc patients fulfilling the 2013 ACR/EULAR classification criteria were recruited. Clinical and laboratory findings, modified Rodnan skin score (mRSS), activity index, videocapillaroscopy, echocardiography, and lung function data were analyzed. Liver stiffness (LS) was measured by transient elastography (TE), with 7 kPa used as the cut-off value for significant liver fibrosis. In addition, hepatic steatosis was evaluated by means of controlled attenuation parameter (CAP) findings. Specifically, CAP values ≥ 238 ≤ 259 dB/m were considered consistent with mild steatosis (S1), values ≥ 260 ≤ 290 dB/m were compatible with moderate steatosis (S2), and values ≥ 291 dB/m were indicative of severe steatosis (S3). Results The median age of patients was 51 years, with a median disease duration of 6 years. The median LS was 4.5 (2.9-8.3) kPa; 69.5% of patients had no evidence of fibrosis (F0); 27.1% displayed LS values between 5.2 and 7 kPa; and only 3.4% of patients had LS values > 7 kPa (F3). The median CAP value for liver steatosis was 223 dB/m (IQR: 164-343). Overall, 66.1% of patients did not show evidence of steatosis (CAP values < 238 dB/m); 15.2% showed values consistent with mild (S1) steatosis (CAP value ≥ 238 ≤ 259 dB/m); 13.5% had moderate (S2) steatosis (CAP value ≥ 260 ≤ 290 dB/m); and 5.1% were deemed to have severe steatosis (S3) due to CAP values ≥ 291 dB/m. Conclusions Although systemic sclerosis is associated with fibrosis of the skin and several organs, only 3.4% of our patient population showed evidence of marked liver fibrosis, which is the same prevalence as that expected in the general population. Therefore, fibrosis of the liver did not appear to be a significant concern in SSc patients, albeit moderate fibrosis could still be detected in a significant proportion of subjects. A prolonged follow-up may clarify whether liver fibrosis in SSc patients may still progress. Likewise, the prevalence of significant steatosis was low (5.1%) and depended on the same variables associated with fatty liver disease in the general population. TE was shown to be an easy and valuable method for detection and screening of hepatic fibrosis in SSc patients with no additional risk factors for liver disease and may be useful to assess the potential progression of liver fibrosis over time.

Comparison of superb microvascular imaging and shear wave elastography for assessing liver fibrosis in chronic hepatitis B

Purpose

The present study investigated the effectiveness and applicability of superb microvascular imaging (SMI) in determining the degree of liver fibrosis noninvasively in comparison with shear wave elastography (SWE).

Methods

Ninety-eight consecutive patients with chronic hepatitis B who underwent ultrasound (US)-guided needle biopsy were examined using US combined with SMI and SWE. The predictive performance of the two US techniques in staging liver fibrosis and inflammation was compared with reference to the histological findings obtained from liver biopsy. The intraobserver and interobserver reproducibility of SMI in vascularity scores were evaluated.

Results

SWE values and SMI vascular scores were statistically significantly different among fibrosis stages (χ²(3)=76.3, χ²(3)=81.5, P<0.001). The SWE and SMI models significantly predicted fibrosis stages separately, and SMI scores alone predicted fibrosis stages better than SWE values (50.1% for SWE, 63.5% for SMI, P<0.001). A model with both SMI scores and SWE values together explained 73.2% of variance in fibrosis stages. When other clinical and laboratory predictors were added to the model (81.5%, P<0.001), SWE values and SMI scores remained the main predictors of fibrosis stages. SWE and SMI were also applicable in predicting inflammatory grades, explaining 31% and 34% of variance, respectively, and 37.7% when used together (P<0.001).

Conclusion

Both SWE and SMI had good diagnostic performance in determining the degree of liver fibrosis in chronic hepatitis B patients. The efficacy of SMI was better than that of SWE. SMI can improve diagnostic performance for staging liver fibrosis and shows potential for estimating necroinflammation of the liver.

Liver stiffness measurements by 2-dimensional shear wave elastography compared to histological and ultrasound parameters in primary biliary cholangitis

BACKGROUND AND AIMS

Liver stiffness measurements (LSMs) by 2-dimensional-shear-wave elastography (LSM_2D-SWE) are now widely used in hepatology. However, relevant information for primary biliary cholangitis (PBC) is scant. We compare LSM_2D-SWE with liver biopsy (LB) in a cohort of PBC patients in Greece.

METHODS

Data of 68 LBs from 53 PBC patients were retrospectively analyzed and fibrosis stage was compared to LSM_2D-SWE. Forty-six patients (86.8%) were females and at the time of LBx median (IQR) age was 62.6 (53.2-72.1). Demographic, UDCA treatment, histological and B-mode ultrasound data were tested for their influence on LSM_2D-SWE estimates.

RESULTS

Liver fibrosis stages F0-F4 were found in 4, 19, 19, 16 and 10 cases, respectively. Across stages F0-F4, the LSM_2D-SWE was 5.6 (5.1-6.1), 7.0 (5.8-7.7), 9.1 (7.3-11.5), 10.8 (9.9-12.2) and 14.5 (11.9-25.7) kPa, respectively, with highly significant difference (p<.001). The LSM_2D-SWE differed also significantly between F0 vs. F1 (p=.027), F1 vs. F2 (p=.005) and F3 vs. F4 (p=.017). The discriminatory ability of LSM_2D-SWE for mild, significant, severe fibrosis and cirrhosis was highly significant in all comparisons (p<.001), with AUC_2D-SWE 95.3%, 87.4%, 85.3% and 95.3% and accuracy 89.7%, 85.3%, 80.9% and 86.8%, respectively. Among 21 parameters tested, significant predictors of LSM_2D-SWE by multiple linear regression were fibrosis stage, portal inflammation and parenchymal heterogeneity. The portal inflammation grade accounted for 32.2% of LSM variation with adjusted R² 0.428.

CONCLUSIONS

In patients with PBC, LSM measurements by 2D-SWE can reliably discriminate between mild, significant, severe fibrosis and cirrhosis. Measurements are significantly affected by portal inflammation grade.