Ultrasound elastography correlations between anthropometrical parameters in kidney transplant recipients

Abstract

Ultrasound elastography (USE) is a method to assess the stiffness of parenchymatous organs. Shear wave elastography (SWE) is considered to be the most suitable elastography method for the non-invasive kidney transplant (KTx) elasticity assessment. The aim of this study was to assess the implementability of SWE for the evaluation of kidney transplant elasticity measurement depending on the depth of an allograft, body mass index (BMI) and donor age. Secondly, to investigate the associations between SWE stiffness measurements and the clinical parameters. This cross-sectional prospective study involved consecutive 100 KTx patients were grouped according to time from transplantation and their BMI (in BMI<25 group the mean was 22.1±2.4, n=42 and in BMI≥25 group the mean BMI was 29.9±3.3, n=58). Mean estimated glomerular filtration rate was almost similar in both groups: <25 group 54.3 and ≥25 group 53.4 mL/min. Mean elastography results were found statistically different (p=0.006) BMI<25 (8.95±5.84 kPa) and BMI≥25 (5.95±3.16 kPa) groups. Significant correlation was found between SWE and the depth of the measurement (r=−0.4, p<0.05). The variations in USE stiffness values were smallest in patients group with lower BMI. In conclusion, we demonstrated that the non-invasive USE measurement stiffness result depends on a patient’s BMI, the depth of renal allograft and donor age.

Shear-Wave Elastography Variability Analysis and Relation with Kidney Allograft Dysfunction: A Single-Center Study

“…Ma et al reported significantly (p-values < 0.03) positive correlations of cortical (0.26) and medullary stiffness (0.59) with interstitial fibrosis [23]. Järv et al [37] have also reported the association between the cortex and medulla allograft stiffness and body mass index, with lower mean SWE values on overweight or obese patients (p-value = 0.006), a similar result being also found in our cohort.…”

“…We conducted this study to examine the intra-and inter-examinations variability of kidney allografts SWE stiffness as an additional tool in post kidney transplantation evaluation. The patients included in our cohort had similar demographic characteristics in terms of age and gender with the patients investigated by Ma et al [23], but are younger as compared to those investigates by Järv et al [37].…”

“…Shear wave elastography is considered potentially suitable elastography method for the assessment of fibrosis in kidney recipients, but no examination protocol or reference value had yet established [37]. A small amount of evidence relating to SWE for kidney transplant evaluation exists in the scientific literature, showing higher parenchymal stiffness in kidney allograft as compared to stable function [22,23], association with fibrosis [19], significantly lower stiffness values in overweight or obese patients [37]. We conducted this study to examine the intra-and inter-examinations variability of kidney allografts SWE stiffness as an additional tool in post kidney transplantation evaluation.…”

“…Meier et al introduce the serial duplex index (SDI = [(RI t0 /RI t-1 ) × (PI t0 /Pi t-1 )]/(CPP t0 /CPP t-1 ), were CPP = cortex-pelvis proportion, PI = pulsatility index, t0 = values from the day of biopsy, t-1 = values from three to seven days before biopsy) and investigated how its value varies on normal kidney graft function, acute tubular necrosis, acute cellular rejection and acute vascular rejection [39]. However, age [40], pulse pressure, heart rate and cardiac rhythm [41] affect the RIs values and thus could explain the controversially RI results on kidney allograft evaluation [37,40,[42][43][44].…”

Noninvasive Assessment of Interstitial Fibrosis and Tubular Atrophy in Renal Transplant by Combining Point-Shear Wave Elastography and Estimated Glomerular Filtration Rate

“…Nicolas Grenier observed that renal stiffness measured by supersonic shear imaging (SSI) had no correlation with baseline characteristics ( p > 0.05) [ 28 ], which is consistent with our results. However, Järv et al [ 29 ] reported that renal stiffness had negative correlations with age (r = −0.2, p = 0.03) and BMI (r = −0.3, p = 0.01). The reason why their result is different from ours may be that Järv et al included more patients who were more than 5 years post renal transplantation, a group which only accounted for 30% of the patients in our study.…”