The use of contrast-enhanced US in renal transplant: first results and potential clinical benefit

Abstract

The use of echo enhancers has potential to diagnose acute kidney graft rejection in its early stages. US not only identifies kidney perfusion defects but also provides information on the effect of a large peri-renal hematoma.

Time-intensity curve analysis of contrast-enhanced ultrasound is unable to differentiate renal dysfunction in the early post-transplant period - a prospective study

“…The similarities in the TIC analysis of EGF and DGF patients were further supported by the absence of differences in TTP and RT between early acute tubular necrosis (0.21 months) and stable patients (8.31 months) [13]. Conversely, using the bolus technique in the early posttransplant period, acute renal transplant rejection patients in comparison with non-rejecting patients showed an increase in cortex TTP [14, 28], a delay in the first conspicuous increase in the value between the renal cortex and the main renal artery [10], and a delay in the maximum value of the inflow from the segmental arteries to the cortex and to the pyramids [12]. An increase in medullary RT and TTP has also been reported in late (> 20 months) acute rejection compared to stable patients (8 months) [13].…”

“…Groups particularly interested in exploring this question have reported encouraging preliminary results in human and animal studies [7–9]. It is therefore not surprising that the utility of CEUS for assessing the perfusion characteristics of kidney allografts has also been investigated [10, 11]. After CEUS examination, the quantification of allograft perfusion by means of time-intensity curve (TIC) analysis enables the measurement of the rate of blood flow in regions of interest (ROI) in different kidney territories [12].…”

In Situ Kidney Insonation With Microbubble Contrast Agents Does Not Cause Renal Tissue Damage in a Porcine Model

“…In renal tissue, CES has been used without apparent side effects. [16][17][18] However, high-intensity insonation has been reported to cause renal interstitial and glomerular microhemorrhage in anesthetized rats. 9,10 With these experiences in mind, and with the aim of regularly using CES in the evaluation of the kidney microcirculation, our study was conducted to analyze the effects of the direct interaction between contrast microbubbles and high-energy insonation in an anesthetized porcine model.…”

“…Recently published experiences with CES in renal patients have not reported side effects, although in no case was the expressed intention of these studies to explore this phenomenon. 5,[16][17][18] The main limitation of our study was the number of pigs involved, which limited the investigation of various microbubble contrast agent and ultrasound doses with regard to renal damage. Therefore, the possibility existed in this limited study that the location of the damage was missed, particularly given the fact that there was no ability to exceed the level at which damage would definitely occur to show appropriate sampling.…”

Perfusion Disturbances of Kidney Graft Parenchyma Evaluated with Contrast-Enhanced Ultrasonography in the Immediate Period following Kidney Transplantation

“…CE-US however was able to show the true extent of the ischemia with a clear delineation of its borders. Although in other studies CE-US was used for the evaluation of ischemic extent following KTx [12,22], there have been no data on the utility of CE-US in the immediate postoperative period. In this period, the information regarding the presence, number and size of ischemic changes may in many cases give an important hint about the cause of delayed graft function or its worsening.…”