Dear Zhongheng Zhang,

The answer is yes. The following recent publications demonstrate the possiblity to use CEUS for the assessment of microcirculation:

1-Contrast-enhanced ultrasound: A promising method for renal microvascular perfusion evaluation

Ling Wang / Chandra Mohan

Journal of Translational Internal Medicine. Volume 4, Issue 3, Pages 104–108, ISSN (Online) 2224-4018, DOI: 10.1515/jtim-2016-0033, September 2016

Abstract

This article reviews the application of contrast-enhanced ultrasound (CEUS) in gauging renal microvascular perfusion in diverse renal diseases. The unique nature of the contrast agents used in CEUS provides real-time and quantitative imaging of the vasculature. In addition to the traditional use of CEUS for evaluation of kidney masses, it also emerges as a safe and effective imaging approach to assess microvascular perfusion in diffuse renal lesions, non-invasively. Although the precise CEUS parameters that may best predict disease still warrant systematic evaluation, animal models and limited clinical trials in humans raise hopes that CEUS could outcompete competing modalities as a first-line tool for assessing renal perfusion non-invasively, even in ailments such as acute kidney injury and chronic kidney disease.

https://www.degruyter.com/view/j/jtim.2016.4.issue-3/jtim-2016-0033/jtim-2016-0033.xml

2-Contrast-enhanced ultrasonography to evaluate changes in renal cortical microcirculation induced by noradrenaline: a pilot study

Antoine G Schneider, Mark D Goodwin, Anthony Schelleman, Michael Bailey, Lynne Johnson, and Rinaldo Bellomo

Crit Care. 2014; 18(6): 653.

Published online 2014 Dec 2. doi: 10.1186/s13054-014-0653-3

Abstract

Introduction

We used contrast-enhanced ultrasound (CEUS) to estimate the effect of an increase in mean arterial pressure (MAP) induced by noradrenaline infusion on renal microvascular cortical perfusion in critically ill patients.

Methods

Twelve patients requiring a noradrenaline infusion to maintain a MAP more than 60 mmHg within 48 hours of intensive care unit admission were included in the study. Renal CEUS scans with destruction-replenishment sequences and Sonovue® (Bracco, Milano Italy) as a contrast agent, were performed at baseline (MAP 60 to 65 mmHg) and after a noradrenaline-induced increase in MAP to 80 to 85 mmHg.

Results

There was no adverse effect associated with ultrasound contrast agent administration or increase in noradrenaline infusion rate. Adequate images were obtained in all patients at all study times. To reach the higher MAP target, median noradrenaline infusion rate was increased from 10 to 14 μg/min.

Noradrenaline-induced increases in MAP were not associated with a significant change in overall CEUS derived mean perfusion indices (median perfusion index 3056 (interquartile range: 2438 to 6771) arbitrary units (a.u.) at baseline versus 4101 (3067 to 5981) a.u. after MAP increase, P = 0.38). At individual level, however, we observed important heterogeneity in responses (range -51% to +97% changes from baseline).

Conclusions

A noradrenaline-induced increase in MAP was not associated with an overall increase in renal cortical perfusion as estimated by CEUS. However, at individual level, such response was heterogeneous and unpredictable suggesting great variability in pressure responsiveness within a cohort with a similar clinical phenotype.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4262130/

Hoping this will be helpful,

Rafik

Dear Pro. Karaman

Many thanks for your recommended articles. After reading these paper, I found the technique used is by continuous infusion of the contrast (Sonovue). But In my machine (Mindray M9), it uses bolus infusion. parameters calculated in that machine are also quite different from that reported in the literature. I do not know the clinical interpretation of these parameters. Mindray M9 reports the following parameters:

goodness of fit

baseline index

arrival time

time to peak

ascending slope

decending slope

Dear Zhongheng Zhang,

bolus infusion usually provides more information than a constant infusion, since you can observe both the arrival of the contrast agent and its  "washout".

The paramaters you obtain depends on the function that is used to model the data, or on the type of model-free analysis performed on them

Since your machine is reportin a "goodness of fit" I assume ther is an underlying model fit onto the data, and since ther is a descending slope, I reckon it must be a model allowing a rasing of the contrast intensity and a decreasing. Usual models are the Gamma-variate or the log-normal.

As for the parameter reported:

goddness of fit: it is used for assessing how well the model fit the data

arrival time: the time before which there is no apparent contrast agent in the region of interest

time to peak: the time interval from the arrival time to the time at which the intensity curve reaches is maximium value

ascending slope: a measure of how fast the contrast agent "fill" the region of interest, or how fast the intensity curve moves from zero to its peak value. The computation of it may vary, providing slightly different information

descending slope: a measure of how fast the contrast agent is depleted from the region of interest, or how fast the intensity curve moves from peak value to zero, or to some low reference value. The computation of it may vary, providing slightly different information

 I hope this help

Enrico

Dear Enrico Grisan

The information you provided are really useful for me. however, I cannot identify literature that link these parameter to clinical outcomes, such as recovery of AKI and sequalea after an episode of AKI. Also, it is interesting to know how these parameters changes in response to vasopressors.  

Dear Zhongheng Zhang,

the only papers I was able to find are those already pointed at by Rafik Karaman (and a couple of others by Schneider and colleagues).

There are other areas (oncology, rheumatology ...) where the clinical outcomes have been studied, but apparantly not how they are affected by vasopressors.

@Enrico Grisan, Thank you very much for your answers.

Dr. Zhang: how did you measure the variables (TTP, arrival time, slopes) in contrasted images using the Mindray M9 machine??

I`m trying to find the control sequences and I`m not able.

If you can help me, it would be great.