New Ultrasound Techniques Promise Further Advances in AKI and CKD

Abstract

AKI and CKD are important clinical problems because they affect many patients and the associated diagnostic and treatment paradigms are imperfect. Ultrasound is a cost-effective, noninvasive, and simple imaging modality that offers a multitude of means to improve the diagnosis, monitoring, and treatment of both AKI and CKD, especially considering recent advances in this technique. Ultrasound alone can attenuate AKI and prevent CKD by stimulating the splenic cholinergic anti-inflammatory pathway. Additionally, microbubble contrast agents are improving the sensitivity and specificity of ultrasound for diagnosing kidney disease, especially when these agents are conjugated to ligand-specific mAbs or peptides, which make the dynamic assessment of disease progression and response to treatment possible. More recently, drug-loaded microbubbles have been developed and the load release by ultrasound exposure has been shown to be a highly specific treatment modality, making the potential applications of ultrasound even more promising. This review focuses on the multiple strategies for using ultrasound with and without microbubble technology for enhancing our understanding of the pathophysiology of AKI and CKD.

Controversies in acute kidney injury: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Conference

“…45 Since the 2012 guideline, which recommended ultrasound for assessing kidney size and the presence of an obstruction, new imaging techniques have become available, such as contrast-enhanced ultrasound, doppler ultrasound, and blood oxygenation levelÀdependent functional magnetic resonance imaging. [46][47][48] The role of these techniques in changing outcomes of AKI is yet to be determined.…”

Acute kidney injury and disease: Long‐term consequences and management

“…CEUSG has been shown to detect, stratify and monitor AKI and thus helps guide therapy. The ability to predict the progression to CKD following an episode of AKI using ultrasound‐based tissue elasticity imaging and molecular ultrasound imaging, by attaching specific monoclonal antibody to the contrast agent shell surface via a high‐affinity molecular bridge and non‐invasive delivery of therapeutic agents to diseased or injured renal tissue using micro‐bubbles are areas to look forward to in the future …”

“…The ability to predict the progression to CKD following an episode of AKI using ultrasound-based tissue elasticity imaging and molecular ultrasound imaging, by attaching specific monoclonal antibody to the contrast agent shell surface via a high-affinity molecular bridge and non-invasive delivery of therapeutic agents to diseased or injured renal tissue using micro-bubbles are areas to look forward to in the future. 72 Timelines and criteria for defining recovery from an AKI episode have been variable across different studies. Recovery of renal function at hospital discharge, recovery at day 30 or day 90 and the likewise return of renal function to pre-AKI levels based on serum creatinine or eGFRs or dialysis independency at follow up have been variably used to define recovery.…”

Ultrasound super-resolution imaging provides a noninvasive assessment of renal microvasculature changes during mouse acute kidney injury

“…Several diagnostic imaging technologies, including magnetic resonance imaging, 16,17 micro-computed tomography imaging (mCT), 18,19 and ultrasound (US) imaging, [20][21][22] have been used in preclinical studies to evaluate noninvasively and quantitatively the changes of renal microvasculature and renal perfusion for predicting and monitoring progressive kidney disease. However, magnetic resonance imaging and CT scans have important limitations when used in human beings.…”

“…US imaging has the advantage of safety, noninvasiveness, portability, affordability, and ease of use. Several approaches, such as Doppler US imaging 22 and contrast-enhanced ultrasound (CEU) imaging, 20,21 have been explored to diagnose AKI-to-CKD progression in animals and human beings. However, neither technique provides spatial resolution high enough for assessing microvessels, especially in the cortex.…”