Update on the role of elastography in liver disease

Research progress of ultrasound in accurate evaluation of cartilage injury in osteoarthritis

Osteoarthritis (OA) is a prevalent cause of joint algesia, loss of function, and disability in adults, with cartilage injury being its core pathological manifestation. Since cartilage damage is non-renewable, the treatment outcome in the middle and late stages of OA is unsatisfactory, which can be minimized by changing lifestyle and other treatment modalities if diagnosed and managed in the early stages, indicating the importance of early diagnosis and monitoring of cartilage injury. Ultrasound technology has been used for timely diagnosis and even cartilage injury treatment, which is convenient and safe for the patient owing to no radiation exposure. Studies have demonstrated the effectiveness of ultrasound and its various quantitative ultrasound parameters, like ultrasound roughness index (URI), reflection coefficient (R), apparent integrated backscatter (AIB), thickness, and ultrasound elastography, in the early and accurate assessment of OA cartilage pathological changes, including surface and internal tissue, hardness, and thickness. Although many challenges are faced in the clinical application of this technology in diagnosis, ultrasound and ultrasound-assisted techniques offer a lot of promise for detecting early cartilage damage in OA. In this review, we have discussed the evaluation of ultrasonic cartilage quantitative parameters for early pathological cartilage changes.

Point-shear wave elastography generated by acoustic radiation force impulse in chronic pancreatitis

BACKGROUND

Transcutaneous point-shear wave elastography (p-SWE) performed using an acoustic radiation force impulse can be used to quantify pancreatic stiffness in chronic pancreatitis (CP). We aimed to evaluate its usefulness to diagnose and monitor CP.

METHODS

175 participants were included in this prospective study including patients with CP (n = 65), liver cirrhosis (LC; n = 60), alcohol abuse (n = 10) and healthy controls (n = 40). Point-shear wave elastography of the pancreas was performed and quantified as median shear wave velocity (SWV). In the same way, p-SWE of the spleen served as a marker of portal hypertension. The M-ANNHEIM Severity score was used as global marker for disease activity in CP.

RESULTS

Compared to healthy controls, pancreatic SWV was significantly elevated in CP (1.38 vs. 0.96 m/s; p < 0.0001, MWU-test). Pancreatic SWV was increased in alcoholic CP but not in hereditary CP. Receiver operating characteristic analysis revealed 1.2 m/s as the optimal cut-off to identify non-heredity-CP subjects (90% specificity; 81% sensitivity; 92% positive predictive value). Pancreatic SWV correlated significantly with the M-ANNHEIM Severity score, severity of CP-typical complications (both p < 0.05, linear regression analysis), morphological changes of the pancreas and need for hospital treatment (both p < 0.05, MWU-test) but not with exocrine or endocrine insufficiency. Pancreatic SWV >1.7 m/s was identified to predict M-ANNHEIM Severity score ≥11 points. Pancreatic SWV was also elevated in LC (1.42 m/s; p < 0.001), correlating with increased splenic SWV.

CONCLUSION

Transcutaneous pancreatic p-SWE represents a bedside, cost-effective and non-invasive tool which adds valuable information to the process of diagnosing and monitoring CP. By portal hypertension, an increased pancreatic SWV must be expected.

Liver stiffness is associated with right heart dysfunction, cardiohepatic syndrome, and prognosis in pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) can lead to congestive hepatopathy, known as cardiohepatic syndrome (CHS). Hepatic congestion is associated with increased liver stiffness, which can be quantified using shear wave elastography. We aimed to investigate whether hepatic shear wave elastography detects patients at risk in the early stages of PH.

METHODS

Sixty-three prospectively enrolled patients undergoing right heart catheterization (52 diagnosed with PH and 11 with invasive exclusion of PH) and 52 healthy volunteers underwent assessments including echocardiography and hepatic shear wave elastography. CHS was defined as increased levels of ≥2 of the following: gamma-glutamyl transferase, alkaline phosphatase, and bilirubin. Liver stiffness was defined as normal (≤5.0 kPa) or high (>5.0 kPa).

RESULTS

Compared with normal liver stiffness, high liver stiffness was associated with impaired right ventricular (RV) and right atrial (RA) function (median [interquartile range] RV ejection fraction: 54 [49; 57]% vs 45 [34; 51]%, p < 0.001; RA reservoir strain: 49 [41; 54]% vs 33 [22; 41]%, p < 0.001), more severe tricuspid insufficiency (p < 0.001), and higher prevalence of hepatovenous backflow (2% vs 29%, p < 0.001) and CHS (2% vs 10%, p = 0.038). In the patient subgroup with precapillary PH (n = 48), CHS and high liver stiffness were associated with increased European Society of Cardiology/European Respiratory Society 2022 risk scores (p = 0.003).

CONCLUSIONS

Shear wave liver elastography yields important information regarding right heart function and may complement risk assessment in patients with (suspected) PH.

Ultrasonic surface acoustic wave elastography: A review of basic theories, technical developments, and medical applications

Physiological and pathological changes in tissues often cause changes in tissue mechanical properties, making tissue elastography an effective modality in medical imaging. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. However, most current ultrasound elastography methods are based on the bulk shear wave; they can image deep tissues but cannot image superficial tissues. To address this challenge, ultrasonic elastography methods based on surface acoustic waves have been proposed. In this paper, we present a comprehensive review of ultrasound-based surface acoustic wave elastography techniques, including their theoretical foundations, technical implementations, and existing medical applications. The goal is to provide a concise summary of the state-of-the-art of this field, hoping to offer a reliable reference for the further development of these techniques and foster the expansion of their medical applications.

Liver Stiffness Determined by Transient Elastography Is a Simple and Highly Accurate Predictor for Presence of Liver Cirrhosis in Clinical Routine

INTRODUCTION

Early detection of patients with advanced chronic liver disease is critical for the prevention of complications and inclusion in surveillance programs for hepatocellular carcinoma. In daily clinical care, it remains challenging to differentiate early cirrhosis from lower fibrosis grades without performing a liver biopsy. The aim of the present study was to assess the performance of different non-invasive detection tools to differentiate cirrhosis from lower fibrosis grades.

METHODS

Data of 116 patients (51 male, 65 female) with chronic liver disease of various origins undergoing liver biopsy was analyzed. Routine laboratory values, liver stiffness measurement (LSM) by transient elastography, and histological liver assessment were collected.

RESULTS

Robust and significant correlations with the histological fibrosis stage were identified for LSM (r = 0.65), the FAST score (0.64), the FIB-4 (0.48), serum aspartate aminotransferase (AST) concentration (0.41), NFS (0.33), international normalized ratio (INR; 0.30), methacetin breath test results (-0.40), and serum albumin concentration (-0.29) by spearman rank correlation. Receiver operating characteristic curves were built for these parameters to separate patients with cirrhosis from those with any other fibrosis stage. The highest AUC was achieved by LSM (0.9130), followed by the FAST score (0.8842), the FIB-4 (0.8644), the NFS (0.8227), INR (0.8142), serum albumin (0.7710), and serum AST (0.7620). The most promising clinical applicability would be an LSM value of 12.2 kPa, achieving 95.7% sensitivity and 75.3% specificity.

CONCLUSION

LSM and FAST score seem to be robust non-invasive measurements for liver fibrosis. LSM and FAST scores may have the potential to reliably detect patients with liver cirrhosis in clinical routine settings.

Imaging of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) continues to be a global health concern, responsible for a significant number of deaths worldwide. Although most individuals who consume alcohol do not develop ALD, heavy drinkers and binge drinkers are at increased risk. Unfortunately, ALD is often undetected until it reaches advanced stages, frequently associated with portal hypertension and hepatocellular carcinoma (HCC). ALD is now the leading indication for liver transplant. The incidence of alcohol-associated hepatitis (AH) surged during the COVID-19 pandemic. Early diagnosis of ALD is therefore important in patient management and determination of prognosis, as abstinence can halt disease progression. The spectrum of ALD includes steatosis, steatohepatitis, and cirrhosis, with steatosis the most common manifestation. Diagnostic techniques including ultrasound, CT, and MRI provide useful information for identifying ALD and excluding other causes of liver dysfunction. Heterogeneous steatosis and transient perfusion changes on CT and MRI in the clinical setting of alcohol-use disorder are diagnostic of severe AH. Elastography techniques are useful for assessing fibrosis and monitoring treatment response. These various imaging modalities are also useful in HCC surveillance and diagnosis. This review discusses the imaging modalities currently used in the evaluation of ALD, highlighting their strengths, limitations, and clinical applications.

Determination and prospective validation of cut-off values for the diagnosis of liver cirrhosis for point shear-wave elastography/acoustic radiation force impulse imaging using the ACUSON Sequoia ultrasound system

OBJECTIVES

Point shear-wave elastography (pSWE) alias acoustic radiation force impulse (ARFI) imaging is a well-established ultrasound-based technique for the non-invasive assessment of liver tissue stiffness. As cut-off values for liver cirrhosis cannot be transferred from one ultrasound system to another, this study aimed at determining cut-off values for the newly developed Siemens ACUSON Sequoia ultrasound system.

METHODS

In a pilot study phase, two independent examiners conducted 10 pSWE measurements in an elasticity phantom and 32 healthy individuals for the determination of inter-examiner agreement. Afterwards, 22 cirrhotic patients and 57 patients with chronic liver disease undergoing liver biopsy underwent pSWE. Patient characteristics and stiffness values were compared for individuals with and without liver cirrhosis. Diagnostic accuracies of cut-off values for the diagnosis of liver cirrhosis were calculated using areas under the receiver operating characteristics analysis and Youden's index. In a subsequent validation study phase, these cut-off values were validated prospectively in 107 cirrhotic and 68 non-cirrhotic patients.

RESULTS

Inter-examiner agreement was excellent for measurements in the elasticity phantom (intra-class correlation coefficient [ICC] = 0.998; P  < 0.001), and good for measurements in patients (ICC = 0.844; P  < 0.001). The best cut-off value for the diagnosis of liver cirrhosis was 1.405 m/s with an AUC of 0.872, a sensitivity of 88.2% and a specificity of 88.2% ( P  < 0.001).

CONCLUSION

ARFI elastography using the Siemens ACUSON Sequoia showed a good inter-examiner agreement. The optimal cut-off value was lower than the cut-off values described for former generations of ultrasound devices. These preliminary results should be confirmed in larger patient collectives with histology as the reference standard.

Shear wave elastography measured liver stiffness-spleen size-to-platelet ratio for the prediction of high-risk oesophageal varices: a meta-analysis

OBJECTIVES

The potential predictive role of shear wave elastography (SWE) measured liver stiffness-spleen size-to-platelet ratio score (LSPS) for high-risk oesophageal varices (HREV) in patients with cirrhosis remains controversial. A systematic review and meta-analysis was performed to investigate the diagnostic efficacy of SWE-measured LSPS for HREV.

METHODS

Relevant studies were retrieved by searching PubMed, Embase, Web of Science, Wanfang, and CNKI databases. Only studies comparing the diagnostic efficacy of SWE-measured LSPS with oesophagogastroduodenoscopy for HREV in patients with cirrhosis were included. Pooled sensitivity and specificity were calculated with a random-effect model.

RESULTS

Overall, eight cohorts were included. Four of them used point SWE (pSWE) and the other four used 2D-SWE. Pooled results showed that a high LSPS measured by pSWE and 2D-SWE were both associated with satisfying diagnostic efficacy for endoscopic-evidenced HREV, with pooled sensitivity, specificity, diagnostic odds ratio, and pooled area under receiver operating characteristic curve of 0.86, 0.86, 39.36, and 0.92 for pSWE-derived LSPS, and 0.77, 0.86, 20.64, and 0.89 for 2D-SWE-derived LSPS. No significant difference was observed in the diagnostic efficacy between pSWE- and 2D-SWE-derived LSPS ( P all > 0.05). Significant heterogeneity was observed. However, further subgroup and meta-regression analysis failed to show that differences in study design, sex, diagnosis (compensated or overall cirrhosis), or LPSP cutoffs may lead to heterogeneity ( P for subgroup difference > 0.05).

CONCLUSION

A high LSPS with liver stiffness measured by pSWE or 2D-SWE shows satisfying predictive accuracy for HREV in patients with cirrhosis.

Artifacts in two-dimensional shear wave elastography of liver

BACKGROUND

Artifacts are common when using two-dimensional shear wave elastography (2-D SWE) to measure liver stiffness (LS), but they are poorly recognized.

AIM

To investigate the presence and influence of artifacts in 2-D SWE of liver.

METHODS

We included 158 patients with chronic liver disease, who underwent 2-D SWE examination by a novice and an expert. A cross line at the center of the elastogram was drawn and was divided it into four locations: top-left, top-right, bottom-left, and bottom-right. The occurrence frequency of artifacts in different locations was compared. The influence of artifacts on the LS measurements was evaluated by comparing the elastogram with the most artifacts (EMA) and the elastogram with the least artifacts (ELA).

RESULTS

The percentage of elastograms with artifacts in the novice (51.7%) was significantly higher than that of the expert (19.6%) (P < 0.001). It was found that both operators had the highest frequency of artifacts at bottom-left, followed by top-left and bottom-right, and top-right had the lowest frequency. The LS values (LSVs) and standard deviation values of EMAs were significantly higher than those of ELAs for both operators. An intraclass correlation coefficient value of 0.96 was found in the LSVs of EMAs of the two operators, and it increased to 0.98 when the LSVs of the ELAs were used. Both operators had lower stability index values for EMAs than ELAs, but the difference was only statistically significant for the novice.

CONCLUSION

Artifacts are common when using 2-D SWE to measure LS, especially for the novice. Artifacts may lead to the overestimation of LS and reduce the repeatability and reliability of LS measurements.

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.

Accuracy and concordance of two-dimensional shear-wave elastography using transient elastography as the reference in chronic viral hepatitis and HIV infection in Rio de Janeiro, Brazil

OBJECTIVES

Evaluate the accuracy and agreement of two-dimensional shear-wave elastography (2D-SWE) LOGIQ-S8 with transient elastography in patients from Rio de Janeiro, Brazil.

METHOD

This retrospective study compared liver stiffness measurements (LSMs) using transient elastography (M and XL probes) and 2D-SWE GE-LOGIQ-S8 performed by a single experienced operator on the same day in 348 consecutive individuals with viral hepatitis or HIV infection. Suggestive and highly suggestive compensated-advanced chronic liver disease (c-ACLD) were defined by transient elastography-LSM ≥10 kPa and ≥15 kPa, respectively. Agreement between techniques and accuracy of 2D-SWE using transient elastography-M probe as the reference was assessed. Optimal cut-offs for 2D-SWE were identified using the maximal Youden index.

RESULTS

Three hundred five patients [61.3% male, median age = 51 [interquartile range (IQR), 42-62] years, 24% with hepatitis C virus (HCV) ± HIV; 17% with hepatitis B virus (HBV) ± HIV; 31% were HIV mono-infected and 28% had HCV ± HIV post-sustained virological response] were included. The overall correlation (Spearman's ρ ) was moderate between 2D-SWE and transient elastography-M ( ρ  = 0.639) and weak between 2D-SWE and transient elastography-XL ( ρ  = 0.566). Agreements were strong ( ρ  > 0.800) in people with HCV or HBV mono-infection, and poor in HIV mono-infected ( ρ  > 0.400). Accuracy of 2D-SWE for transient elastography-M ≥ 10 kPa [area under the receiver operating characteristic (AUROC) = 0.91 (95% confidence interval [CI], 0.86-0.96); optimal cut-off = 6.4 kPa, sensitivity = 84% (95% CI, 72-92), specificity = 89% (95% CI, 84-92)] and for transient elastography-M ≥ 15 kPa [AUROC = 0.93 (95% CI, 0.88-0.98); optimal cut-off = 7.1 kPa; sensitivity = 91% (95% CI, 75-98), specificity = 89% (95% CI, 85-93)] were excellent.

CONCLUSION

2D-SWE LOGIQ-S8 system had a good agreement with transient elastography and an excellent accuracy to identify individuals at high risk for c-ACLD.

Current and potential methods to assess kidney structure and morphology in term and preterm neonates

After birth, the kidney structure in neonates adapt to the functional demands of extrauterine life. Nephrogenesis is complete in the third trimester, but glomeruli, tubuli, and vasculature mature with the rapidly increasing renal blood flow and glomerular filtration. In preterm infants, nephrogenesis remains incomplete and maturation is slower and may be aberrant. This structural and functional deficit has life-long consequences: preterm born individuals are at higher risk for chronic kidney disease and arterial hypertension later in life. This review assembles the literature on existing and potential methods to visualize neonatal kidney structure and morphology and explore their potential to longitudinally document the developmental deviation after preterm birth. X-rays with and without contrast, fluoroscopy and computed tomography (CT) involve relevant ionizing radiation exposure and, apart from CT, do not provide sufficient structural details. Ultrasound has evolved into a safe and noninvasive high-resolution imaging method which is excellent for longitudinal observations. Doppler ultrasound modes can characterize and quantify blood flow to and through the kidneys. Microvascular flow imaging has opened new possibilities of visualizing previously unseen vascular structures. Recent advances in magnetic resonance imaging display renal structure and function in unprecedented detail, but are offset by the logistical challenges of the imaging procedure and limited experience with the new techniques in neonates. Kidney biopsies visualize structure histologically, but are too invasive and remain anecdotal in newborns. All the explored methods have predominantly been examined in term newborns and require further research on longitudinal structural observation in the kidneys of preterm infants.

INCREASED ARTERIAL STIFFNESS AND ACCELERATED ATHEROSCLEROSIS IN TAKAYASU ARTERITIS

INTRODUCTION

Cardiovascular diseases are the leading causes of morbidity and mortality in patients with Takayasu arteritis (TAK). Arterial stiffness and accelerated atherosclerosis have been reported in TAK, however, morphological changes in the arterial wall have not been adequately addressed. Shear wave elastography (SWE) is a new, non-invasive, direct and quantitative method of ultrasonography (US) that evaluates elasticity of biological tissues.

METHODS

A total of 50 patients with TAK (44F/6 M; mean age: 39.8 ± 8.2 years), 43 with systemic lupus erythematosus (SLE) (38F/5 M; 38.0 ± 7.9 years) and 57 healthy controls (HCs) (50F/7M: 39.5 ± 7.1 years) were studied using carotid B mode US and SWE. Carotid artery intima-media thickness (CCA IMT) and SWE were measured and the atherosclerotic plaques were recorded. Clinical characteristics and cardiovascular risk factors were determined. Intra and inter observer reproducibility was assessed and found good agreement.

RESULTS

The mean IMT in the right and left carotid arteries was significantly higher only among patients with TAK when compared to SLE and HCs. Carotid artery plaques were significantly increased only in patients with TAK. On the other hand, the mean SWE value was significantly increased among both TAK and SLE patients when compared to HCs, whereas patients with TAK had the highest value. These were also true after adjustments were made for atherosclerotic risk factors and after all those with atherosclerotic plaques were excluded from the analysis. TAK itself, diastolic blood pressure levels and IMT were independently associated with SWE.

CONCLUSIONS

Markedly increased CCA IMT and SWE values appear to be uniquely associated with TAK, suggesting that they could be used as diagnostic tools. Arterial stiffness occurs independently from atherosclerosis and is associated with arterial thickening. Further studies should investigate whether CCA SWE values could predict cardiovascular morbidity and mortality. Strong association with premature atherosclerosis could be also considered as a unique feature of TAK.