ESPN 50th Annual Meeting

ESPN 2017


 
Correlation of Acoustic Radiation Force Impulse (ARFI) Elastography with Histological Findings in Pediatric Renal Transplant Patients
ELKE WÜHL 1 NORA SZéKELY 2 ABDULSATTAR ALRAJAB 2 THI THANH TAM BUI-TA 2 ALEXANDER FICHTNER 1 BURKHARD TÖNSHOFF 1 JENS-PETER SCHENK 2

1- DIVISION OF PEDIATRIC NEPHROLOGY, CENTER FOR PEDIATRICS AND ADOLESCENT MEDICINE, UNIVERSITY HOSPITAL HEIDELBERG, GERMANY
2- DIR, DIVISION OF PEDIATRIC RADIOLOGY, UNIVERSITY HOSPITAL HEIDELBERG, HEIDELBERG, GERMANY
 
Introduction:

‘Acoustic Radiation Force Impulse’ elastography (ARFI) is a new methodology for determining tissue and organ stiffness by ultrasound measurement of shear wave velocity (SWV). Data on ARFI in renal transplantation are limited and there are no data on ARFI in children having renal biopsies for suspected transplant rejection. We aimed to correlate ARFI measurements with histological findings in renal transplant biopsies.

Material and methods:

SWV was measured using a 9 MHz linear probe (9L4) and the Siemens Acuson S3000 Helx ultrasound device equipped with Virtual TouchTM Quantification (VTQ, Siemens, Erlangen, Germany) focusing the region of interest on the central parenchyma/columns of Bertin. Data from 38 pediatric renal transplant patients with suspected rejection, having renal biopsies within one week of ARFI measurement, were analyzed (71% boys; mean age 13.3±6.3 years, time since transplantation 3.6±3.8 years, mean donor age 31.4±13.0 years, mean eGFR 43.3±21.4 mL/min/1.73m2). Histological lesions were graded according to the BANFF 2015 classification.

Results:

13/38 patients had histological signs of chronic-active rejection. In these patients, SWV was significantly increased compared to patients without rejection (3.31 ± 0.79 m/sec vs. 2.68 ± 0.49 m/sec, p=0.005). Regarding staging of interstitial fibrosis and tubular atrophy (IFTA, ci and ct grading 0 to 3), SWV increased with increasing scores. The difference in SWV was significant for patients with IFTA3 and ct3 compared to those with lower grading (p < 0.05). SWV was correlated with the percentage of sclerotic glomeruli (r=0.44, p=0.006). No correlations were found between conventional resistance index measurements and histological findings.

Conclusions:

Shear ware velocity, a measure of tissue stiffness, correlates with the histological findings of fibrosis in pediatric renal allografts. Further studies are warranted to determine whether ARFI is of additional use in the assessment of renal graft outcome.