Renal Shear Wave Velocity Research Articles

Renal Acoustic Radiation Force Impulse Elastography in Hypertensive Nephroangiosclerosis Patients

Objective: Hypertensive nephroangiosclerosis (HN) represents the second most common cause of chronic kidney disease. Kidney damage secondary to high blood pressure favors the appearance of serum and urinary changes, but also imaging, highlighted by ultrasonography (B-mode, Doppler, Acoustic Radiation Force Impulse Elastography). Acoustic Radiation Force Impulse Elastography (ARFI) represents a new imagistic method which characterizes renal stiffness in the form of shear wave velocity (SWV). Aim: This study aims to investigate renal stiffness in HN patients, and to assess the correlations between it and urinary albumin/creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and intrarenal resistive index (RRI). Material and Methods: This cross-sectional study was performed on a group of 80 HN patients and 50 healthy, sex and age-matched, as controls. UACR (urinary immunoturbidimetry), eGFR (Jaffe method), RRI, and renal SWV (Siemens Acuson 2000) were determined in all patients and controls. Data were expressed as mean ± standard deviation. Statistical analysis was done by means Pearson’s test and t-Student test, p values of less than 0.05 were considered statistically significant. Results: UACR, eGFR, RRI and SWV showed statistically significant differences between the HN patients and controls (p < 0.0001). In the hypertensive patients group, statistically significant correlations were observed between the SWV and UACR (r = −0.7633, p < 0.00001), eGFR (r = 0.7822, p = 0.00001), and RRI (r = −0.7978, p = 0.00001). Conclusions: Kidney sonoelastography characterizes imagistically the existence of intrarenal lesions associated with essential hypertension, offering a new diagnosis method for these patients.

Correlation between shear wave velocity of renal parenchyma and TGF-β1 in chronic allograft nephropathy

Objective To evaluate the change of shear wave velocity (SWV) of renal parenchyma and serum level of transforming growth factor beta 1 (TGF-β1) in the patients with chronic allograft nephropathy (CAN), and further evaluate the correlation between them. Methods A total of 60 patients with chronic allograft nephropathy confirmed by renal biopsy were selected and divided into three groups according to the degree of interstitial fibrosis and tubular atrophy of the transplanted kidney: group C1 (renal cortex involvement 50%, n=20). 30 renal transplant recipients with normal renal function were enrolled for control group. The SWV of the renal were measured by virtual touch tissue quantification (VTQ) and the serum level of TGF-β1 were detected by enzyme linked immunosorbent assay (ELISA) in each group. Results Compared with control group, the SWV and serum TGF-β1 in case groups were significantly higher (P<0.05). SWV measured values: group C3 was the highest, group C2 was middle one and group C1 was the lowest (P<0.05). Statistically significant difference in serum TGF-β1 was observed among these three groups (P<0.05). The renal SWV and serum TGF-β1 had a significant positive correlation (r=0.631, P<0.05). Conclusions Both renal SWV and serum TGF-β1 increase as CAN progressed, which have high value in the diagnosis and treatment of CAN. Key words: Kidney transplantation; Kidney diseases; Ultrasonography, doppler, color; Transforming growth factor beta1

Renal Cortical Elastography: Normal Values and Variations

IntroductionRenal cortical elastography has shown conflicting but promising results in evaluation of chronic kidney disease and other renal disorders. The purpose of this study was to establish a normogram of renal cortical elasticity values and assess their variation between right and left kidney and their relation with age, gender, body mass index, renal dimensions and skin to cortex distance. MethodsThe study was a hospital based cross sectional study performed at Tribhuvan University Teaching Hospital, a tertiary care center in Kathmandu, Nepal. All individuals referred for Ultrasound from General Health Check up clinic were included in the study. Patient with abnormal ultrasound findings and abnormal renal function test were excluded from the study. Renal morphometry including length, cortical thickness, and skin to cortex distance were measured in B mode imaging and renal cortical elastography was measured with region of interest box of 1 × 0.5 cm. All analyses were done using Statistical Package for Social Sciences 20.0 soft ware. ResultsA total of 95 individuals who met the inclusion criteria were included in the study. The mean values of right and left renal cortical shear wave velocity were 1.49 ± 0.19 m/s and 1.54 ± 0.19 m/s respectively. Statistical significant difference was observed between the renal cortical shear wave velocity of right and left kidney. The renal shear wave velocity was seen to decrease with age, however the correlation was not statistically significant. No significant difference was also noted in renal shear wave velocity among various sex or Body mass index groups. Statistically significant negative correlation was noted between skin to cortex distance and renal cortical shear wave velocities. However no statistically significant correlation was noted between renal dimensions and renal cortical shear wave velocities. ConclusionsThe normal cortical elasticity values in terms of shear wave velocity of right and left kidney were established. Renal elasticity is independent of the age, gender, Body mass index and renal dimensions.

Renal shear wave velocity by acoustic radiation force impulse did not reflect advanced renal impairment.

Acoustic radiation force impulse is a noninvasive method for evaluating tissue elasticity on ultrasound. Renal shear wave velocity measured by this technique has not been fully investigated in patients with renal disease. The aim of the present study was to compare renal shear wave velocity in end-stage renal disease patients and that in patients without chronic kidney disease and to investigate influencing factors. Renal shear wave velocities were measured in 59 healthy young subjects (control group), 31 subjects without chronic kidney disease (non-CKD group), and 39 end-stage renal disease patients (ESRD group). Each measurement was performed 10 times at both kidneys, and the mean value of eight of 10 measurements, excluding the maximum and minimum values, was compared. Renal shear wave velocity could be measured in all subjects. Renal shear wave velocity in the control group was higher than in the non-CKD group and in the ESRD group, and no difference was found between the non-CKD group and the ESRD group. Age and depth were negatively correlated to the renal shear wave velocity. In multiple regression analysis, age and depth were independent factors for renal shear wave velocity, while renal impairment was not. There was no difference between the non-CKD group and the ESRD group, even when ages were matched and depth was adjusted. Renal shear wave velocity was not associated with advanced renal impairment. However, it reflected alteration of renal aging, and this technique may be useful to detect renal impairment in the earlier stages.

Clinical Values of Studying Kidney Elasticity with Virtual Touch Quantification in Gestational Hypertension Patients.

BackgroundThe aim of this study was to investigate the differences in shear wave velocity (SWV) in renal cortex, renal medulla, and renal sinuses between gestational hypertension and normal pregnant women.Material/MethodsNinety patients with gestational hypertension and 30 women with normal pregnancy were enrolled in this study. Kidney biopsy was performed within 6 weeks to 3 months postpartum to determine the pathological nature of renal injury. According to the classification criteria for gestational hypertension, the patients were divided into 3 groups. Gestational hypertension only patients were classified as Group A; patients with mild preeclampsia as group B; patients with severe preeclampsia as group C; normal pregnant women as a control group. Virtual Touch Quantification technique was used to measure renal shear wave velocity; blood pressure, urine analysis, and renal function were also tested.ResultsThere was no difference in renal function between patients in group A and the control group (p>0.05), but there was a significant difference in renal function among patients in group A, B, and C, and there was a significant difference in renal function between patients in group B and C versus control (p<0.05 for all comparisons). There was also a significant difference in SWV values of the renal cortex, renal medulla, and renal sinus between patients in group A, B, and C versus control group (p<0.05).ConclusionsThe SWV values of the renal cortex, renal medulla, and renal sinus in patients with gestational hypertension were smaller than those of normal pregnant women, and the more severe the kidney injury, the smaller the SWV value.

Renal shear wave velocity and estimated glomerular filtration rate in children with chronic kidney disease.

A shear wave velocity (SWV) value obtained by the acoustic radiation force impulse technique depends on tissue elasticity. We investigated the relationship between SWV values and the estimated glomerular filtration rate (eGFR) in children with chronic kidney disease. A total of 29 patients were enrolled in the study. There were 18 primary and 11 secondary cases of vesicoureteral reflux. eGFR was calculated using Schwartz's formulas (2012). Partial eGFR for each kidney was assessed by multiplying the eGFR by the percentage of renal function measured by means of renal (99m)Tc-dimercaptosuccinic acid scintigraphy. All ultrasound tests were done by a single qualified technician using a convex probe (frequency 4 MHz) on an S-2000 system. The mean SWV values of the two kidneys were significantly and negatively correlated with eGFR calculated with both univariate (cystatin C [Cys C] and multivariate (creatinine, Cys C, and nitrogen) equations. Of all the formulae, the strongest correlation was obtained with eGFR (Cys C). SWV of the renal cortex correlates with the eGFR of patients affected by malformative uropathies. Nevertheless, this technique needs standardization and validation.

Value of virtual touch tissues quantization in the stages of type 2 diabetic nephropathy

Objective To investigate the application value of virtual touch tissues quantization(VTQ)in the stages of type 2 diabetic nephropathy.Methods 120 cases of type 2 diabetes were divided into 3 groups according to urinary albumin excretion rate (UAER):diabetes without urinary albumin,diabetes with trace albuminuria and diabetes with mass albuminuria.The control group consisted 30 normal cases.VTQ was used to measure the renal shear wave velocity (SWV),then compare were made between the 4 groups.Besides,correlation analysis was made between SWV and UAER in diabetic nephropathy group.Results When compared SWV,there was no significant difference between diabetes without urinary albumin and control group (P =0.144),but there was significant difference between each 2 group of diabetes with trace albuminuria,diabetics with mass albuminuria group and control group (P ＜ 0.05).There was also significant difference between each 2 group of diabetes (P ＜ 0.05).The correlation coefficients for SWV and UAER in diabetes were 0.697(P ＜0.05).ROC analyses showed the area under curves for SWV diagnosis for diabetic nephropathy was 0.93.The best cutoff point,sensitivity and specificity were 2.43 m/s,85.7％ and 84.5 ％,respectively.Conclusions The renal SWV increases as the renal injury progresses,which also plays an important role in diabetic nephropathy stages. Key words: Ultrasonography; Diabetic nephropathy; Virtual touch tissues quantization