Comparison of point-shear wave elastography (ElastPQ) and transient elastography (FibroScan) for liver fibrosis staging in patients with non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: ElastPQ is a point shear wave elastography technique used to non-invasively assess liver fibrosis. We compared liver stiffness measurements (LSM) by ElastPQ and fibroscan transient elastography (F-TE) in a cohort of patients with non-alcoholic fatty liver disease (NAFLD). We further evaluated the performance of ElastPQ in a subgroup of patients with available liver histology. MATERIALS AND METHODS: We included patients with NAFLD who presented in a dedicated multidisciplinary clinic. Anthropometric parameters, blood tests and elastography measurements were obtained using F-TE and ElastPQ as part of routine clinical care. RESULTS: We enrolled 671 patients with NAFLD, mean age 55.8 ± 13 years, body mass index (BMI) 31.5 ± 5.7 kg/m2 , 56.6% males, 41% diabetes, 53.7% hypertension, 68% dyslipidaemia. ElastPQ showed an excellent correlation with F-TE (Spearman's r = 0.80, p < .001), which was better for mild/moderate stages of fibrosis. Independent predictors of a >2 kPa discrepancy between the two techniques were a larger waist circumference and F-TE ≥10 kPa. In the subgroup of 159 patients with available histology, ElastPQ showed similar diagnostic accuracy with F-TE in staging liver fibrosis (ElastPQ area under the curves 0.84, 0.83, 0.86 and 0.95, for F ≥ 1, F ≥ 2, F ≥ 3 and F = 4 respectively). Optimal cut-off values of ElastPQ for individual fibrosis stages were lower than those of F-TE. CONCLUSIONS: ElastPQ shows an excellent correlation with F-TE in patients with NAFLD, which was better for lower LSM. The optimal cut-off values of ElastPQ are lower than those of F-TE for individual stages of fibrosis. ElastPQ has similar diagnostic accuracy to F-TE for all stages of fibrosis.

Correlation of Point Shear Wave Velocity and Kidney Function in Chronic Kidney Disease.

OBJECTIVES: Point shear wave elastography is a quantitative ultrasound-based imaging method used in the assessment of renal disease. Among point shear wave elastographic options, 2 techniques have been studied considerably: Virtual Touch quantification (VTQ; Siemens AG, Erlangen, Germany) and ElastPQ (EPQ; Philips Healthcare, Bothell, WA). Both rely on the tissue response to an acoustic beam generated by the ultrasound transducer. The data on renal VTQ are more extensive, whereas EPQ has been used less thus far in the assessment of the kidneys. This study aimed to evaluate the performance of EPQ in the kidney and compare it with VTQ. METHODS: We studied 124 participants using EPQ: 22 with no renal disease and 102 with chronic kidney disease (CKD). Ninety-one were studied with both the EPQ and VTQ methods. We obtained 5 valid measurements in each kidney, expressed in meters per second. RESULTS: The mean kidney stiffness measurements ± SD obtained with EPQ in the healthy control group were as follows: right kidney, 1.23 ± 0.33 m/s; and left kidney, 1.26 ± 0.32 m/s (P = .6). In the patients with CKD (all stages), the mean kidney stiffness measurements obtained were significantly lower: right kidney, 1.09 ± 0.39 m/s; and left kidney, 1.04 ± 0.38 m/s (P = .4). We observed that, similar to VTQ, EPQ values decreased with CKD progression, based on analysis of variance results using different CKD stages. From a receiver operating characteristic curve analysis, the cutoff value for an estimated glomerular filtration rate of less than 45 mL/min was 1.24 m/s, and the value for an estimated glomerular filtration rate of less than 30 mL/min was 1.07 m/s. CONCLUSIONS: When using EPQ, the kidney shear wave velocity is decreased in patients with CKD, an observation similar to that obtained by using the VTQ method.

Correlation Between Renal Cortical Stiffness and Histological Determinants by Point Shear-Wave Elastography in Patients With Kidney Transplantation.

INTRODUCTION: Renal allograft biopsy is the gold standard for the detection of histological lesions of chronic allograft dysfunction. The identification of a noninvasive routine test would be desirable. Elastosonography is used to assess tissue stiffness according to viscosity, and no data are available on the use of point quantification shear-wave elastography (ElastPQ) for the evaluation of renal chronic lesions. RESEARCH QUESTION: To evaluate the feasibility of ElastPQ to assess cortical allograft stiffness and to determine the correlation of clinical, biological, and pathological factors with the diagnostic accuracy of kidney stiffness values in patients with histological lesions. DESIGN: Forty-two patients underwent kidney transplant biopsy and 10 valid measurements of ElastPQ, blindly performed by 2 operators. The interobserver reproducibility was assessed according to intraclass correlation coefficient. The ElastPQ measurements and the clinical data were compared using the Spearman correlation analysis. RESULTS: 97.6% reliable measurements were obtained using ElastPQ, with an excellent interobserver agreement. The kidney stiffness was significantly higher in the patients with a time since transplantation >12 months and was correlated with chronic lesions (interstitial fibrosis, tubular atrophy transplant glomerulopathy, and mesangial matrix), with the interstitial fibrosis/tubular atrophy, score and with the sum of the scores of the chronic lesions. Mesangial matrix increase is the only independent determinant of kidney stiffness. DISCUSSION: ElastPQ is a noninvasive, reproducible, and sensitive diagnostic tool able to detect moderate/severe chronic lesions. Its routine use during follow-up can identify patients eligible for biopsy, which remains the gold standard exam for detecting chronic allograft dysfunction.

Placental elastography in second trimester preeclampsia prediction: A prospective study.

Objective: The aim of the study was to evaluate the diagnostic potential of placental shear wave elastography in predicting preeclampsia at 16 to 20 weeks of gestation. Materials and methods: A total of 230 pregnant women between 16 and 20 weeks of gestation were observed for the study. These women underwent shear wave elastography ElastPQ (Philips Healthcare, Bothell, Washington, USA) of the placenta. The mean value of placental shear modulus was obtained for each participant. These participants were followed up for the development of preeclampsia and were divided into two groups; group A included those who developed preeclampsia and group B included those who remained normotensive until delivery. The elasticity values of the two groups were compared, and the ROC curve was drawn to obtain the best cut-off value that would predict the onset of preeclampsia. Results: Placental shear modulus varied from 1.03 kPa to 7.4 kPa at 16 to 20 weeks of gestation with an average of 2.74 ± 0.87 kPa. There was a statistically significant difference in the mean value of elasticity between two groups, being 4.61 kPa in group A and 2.51 kPa in group B. Maximum diagnostic accuracy was obtained at 2.9667 kPa with area under the curve 0.970, sensitivity 92%, specificity 91.71%, positive predictive value 57.5% and negative predictive value 98.9%. Conclusion: Stiffness of placenta, quantitatively measured by SWE at 16 to 20 weeks of gestation, is higher in the women who develop preeclampsia and hence may be used for predicting preeclampsia.

Noninvasive Assessment of Liver Fibrosis with ElastPQ in Patients with Chronic Viral Hepatitis: Comparison Using Histopathological Findings.

Chronic viral hepatitis is a major cause of chronic liver disease leading to liver fibrosis. This study aimed to assess the diagnostic performance of elastography point quantification (ElastPQ), transient elastography (TE), and aspartate aminotransferase-to-platelet count ratio index (APRI) for the staging of liver fibrosis in patients with chronic viral hepatitis using histopathological findings as a reference standard. For 122 patients with chronic viral hepatitis, diagnostic performance was evaluated using area under the receiver operating characteristic curve (AUROC) analysis and correlations were determined using Spearman's correlation coefficient. The AUROC of ElastPQ for the diagnosis of the fibrosis stage ≥ F2 was 0.917 with a cut-off value of 3.935. There was a significant positive correlation between the different stages of histologic liver fibrosis and stiffness values obtained using ElastPQ, TE, and APRI (ρ = 0.556, ρ = 0.657, ρ = 0.375, respectively; p < 0.001). ElastPQ showed a higher diagnostic accuracy than APRI, resembling that of TE; AUROC values of ElastPQ, TE, and APRI were 0.917, 0.964, and 0.896, respectively, for a fibrosis stage ≥ F2. ElastPQ is a promising noninvasive technique with a diagnostic accuracy comparable with that of TE for the evaluation of liver fibrosis in patients with chronic viral hepatitis.

Comparison of Elastography Point Quantification with Transient Elastography in Patients with Chronic Viral Hepatitis and Nonalcoholic Fatty Liver Disease: A Pilot Study.

AIMS: The objective of this study was to compare diagnostic accuracy of elastography point quantification (ElastPQ) with transient elastography (TE) and liver histology for measuring liver stiffness in patients with chronic viral hepatitis (CVH) and nonalcoholic fatty liver disease (NAFLD). METHODS: Thirty-two patients with chronic liver disease (CVH and NAFLD) were evaluated by ElastPQ and TE within 7 days of liver biopsy. Within the CVH group, subgroup analysis was carried out in patients with end-stage renal disease (ESRD) and without ESRD. Area under the receiver operating characteristic (AUROC) curves were calculated for ElastPQ and TE. RESULTS: There were 15 patients with CVH and 17 patients with NAFLD. In the CVH group, there were 8 patients with ESRD and 7 patients without ESRD. Taking liver histopathology as the gold standard, liver stiffness measurement by ElastPQ (ρ = 0.826;P < 0.0001) and TE (ρ = 0.649; P < 0.0001) correlated significantly with the stage of fibrosis. AUROCs of ElastPQ and TE for the diagnosis of any fibrosis (F ≥ 1), significant fibrosis (F ≥ 2), and advanced fibrosis (F ≥ 3) were 0.907, 0.959, 0.926 and 0.870, 0.770, 0.881, respectively, in both CVH and NAFLD groups. However, the accuracy of both these techniques was poor in patients with CVH and ESRD (AUROCs for ElastPQ and TE of 0.667 and 0.167 for the diagnosis of significant fibrosis, respectively, and 0.429 and 0.143 for the diagnosis of advanced fibrosis, respectively). The diagnostic accuracy of both ElastPQ and TE for detecting significant fibrosis was excellent in patients with NAFLD (AUROC of 1.000 and 0.936, respectively). ElastPQ was superior to TE in the diagnosis of significant fibrosis in the combined analysis (P = 0.0149) and in the CVH group (P = 0.0391), while both modalities were comparable in patients of the NAFLD group (P = 0.2539). CONCLUSION: ElastPQ may be equally accurate as Fibroscan, and large prospective studies are required to validate the same.

Role of intrarenal resistive index and ElastPQ® renal shear modulus in early diagnosis and follow-up of diabetic nephropathy: A prospective study.

Introduction: We aimed to establish baseline normal values of ElastPQ® (Philips Healthcare, Bothell, Washington, USA) renal shear modulus, evaluate changes in intrarenal resistive index and renal shear modulus in various stages of diabetic nephropathy, their diagnostic potential and role in follow-up. Methods: Our prospective observational study was performed over two years. In total, 130 adult cases with diabetic nephropathy and 130 normal adult controls were selected. Diabetic nephropathy was confirmed by persistent albuminuria on 24-hour urinary albumin testing at three month intervals and staged by albuminuria quantification. Measurement of intrarenal resistive index and renal shear modulus in all subjects was performed and their variation with stage of nephropathy was statistically analyzed using Pearson's correlation. Receiver operating characteristic curves were plotted and their individual and combined diagnostic potentials were assessed. Statistical significance was tested using t tests and analysis of variance. Interrater agreement was tested using Cohen's kappa coefficient. Results: Mean intrarenal resistive index was significantly higher for cases (mean 0.72 ± 0.05) than controls (mean 0.62 ± 0.04) and showed significant age variation (p < 0.05). Normal values of ElastPQ® renal shear modulus ranged from 3.87 to 4.72 kPa and was significantly higher for cases (mean 8.59 ± 1.77 kPa) than controls (mean 4.32 ± 0.45 kPa) and showed significant differences between each stage of nephropathy, being highest in stage 2. Maximum diagnostic accuracy was at 0.65 (sensitivity 90%, specificity 76.2%, area under curve 0.916) for intrarenal resistive index and at 5.31 kPa (sensitivity 90.8%, specificity 84.6%, area under curve 0.923) for renal shear modulus. Combination of the two further improved diagnostic performance (highest accuracy of 89%, sensitivity 81.7%, specificity 96.3%). Conclusions: Normal range of ElastPQ® renal shear modulus values could be established. Intrarenal resistive index and renal shear modulus can be used as imaging parameters for early diagnosis and follow-up of diabetic nephropathy.

The value of ElastPQ for the evaluation of liver stiffness in patients with B and C chronic hepatopathies.

The aim of this study was to evaluate the diagnostic performance of a point shear wave elastography using ARFI technique - ElastPQ, in patients with B and C chronic hepatopathies, using Transient Elastography (TE) as the reference method, since it is a validated method for liver fibrosis assessment. SUBJECTS AND METHODS: the study included 228 consecutive subjects with chronic hepatopathies (26% HBV, 74% HCV) from whom 51% had liver cirrhosis. Liver stiffness (LS) was evaluated in the same session by means of 2 elastographic methods: TE (FibroScan, EchoSens) and ElastPQ (Affinity, Philips) techniques. For TE 10 valid LS measurements were performed for each patient and the median value was calculated. Reliable LS measurements by TE (M or XL probe) were considered the median value of 10LS measurements with a success rate ≥60% and an interquartile range <30%. For ElastPQ we calculated the median value of 10LS measurements in the liver parenchyma, at least 1cm below the capsule, avoiding large vessels. For differentiating between stages of liver fibrosis we used the TE cut-off values published in the Tsochatzis meta-analysis: significant fibrosis (F≥2)- 7.0kPa, severe fibrosis (F≥3)- 9.5kPa and for liver cirrhosis (F=4)-12kPa (Tsochatzis et al., 2011). The areas under the receiver operating characteristic curve (AUROCs) were used to assess the diagnostic performance of ElastPQ, correlations between ElastPQ and TE were evaluated. RESULTS: Valid LS measurements were obtained in 90.7% (207/228) cases by means of TE and in 98.7% (225/228) cases with ElastPQ. In the final analysis 205 patients were included. The ElastPQ values ranged from 2.32 to 44.07kPa (median=10.42kPa). Based on TE cut-off values (Tsochatzis et al., 2011) we divided our cohort into 4 groups: F0-F1:61/205 (29.8%); F2: 14/205 (6.8%); F3: 15/205 (7.3%); F=4: 115/205 (56.1%). The best cut-off values for discriminating, significant, severe fibrosis and cirrhosis were 7.2, 8.5 and 8.9kPa, respectively. The AUROCs were calculated considering TE as the reference method: 0.94 for significant fibrosis (F≥2), 0.97 for severe fibrosis (F≥3) and 0.97 for cirrhosis (F=4). In our cohort there was a strong correlation between measurements obtained by Transient Elastography and ElastPQ (r=0.85, p<0.001). CONCLUSIONS: ElastPQ seems to have a good diagnostic accuracy for staging liver fibrosis.

Non-invasive Assessment of Liver Fibrosis with ElastPQ: Comparison with Transient Elastography and Serologic Fibrosis Marker Tests, and Correlation with Liver Pathology Results.

We investigated the feasibility of using ultrasound shear wave elastography point quantification (ElastPQ) for liver fibrosis staging and compared it with other non-invasive tools with respect to efficacy in liver stiffness measurement. A total of 106 patients who underwent liver stiffness measurements, using ElastPQ and biochemical investigations, before parenchymal liver biopsy or surgery were included. Among these, 51 also underwent transient elastography (TE). Correlations of ElastPQ, TE and aspartate aminotransferase-to-platelet ratio index (APRI) with histopathological findings (as the reference standard) were determined using Spearman's correlation coefficient. The diagnostic performance of ElastPQ, TE and APRI was evaluated using receiver operating characteristic (ROC) curve analysis. ElastPQ had good diagnostic accuracy in identifying each liver fibrosis stage, with an area under the ROC curve (AUC) of 0.810 to 0.864. Stiffness values obtained using ElastPQ, TE and APRI were significantly positively correlated (r = 0.686, r = 0.732 and r = 0.454, respectively) with histologic fibrosis staging (p < 0.001). According to the AUC for the diagnosis of significant fibrosis (≥F2) and cirrhosis (=F4), ElastPQ had better diagnostic accuracy (AUC = 0.929 and 0.834, respectively) than APRI (AUC = 0.656 and 0.618, respectively) (p < 0.05), and was similar to TE (AUC = 0.915 and 0.879, respectively). ElastPQ is a promising ultrasound-based imaging technique for evaluation of liver fibrosis, with a diagnostic accuracy comparable to that of TE.