New ultrasound techniques for acute kidney injury diagnostics.

Purpose of review: Acute kidney injury (AKI) is common in critical illness and associated with adverse outcomes. Imaging, specifically ultrasound, is increasingly finding a role in AKI diagnostics. This includes the assessment of arterial and venous blood flow, tissue perfusion and the condition of the renal parenchyma. This review provides an update on ultrasound techniques and their application to AKI in critical care.

Recent findings: Advances have been made in arterial and venous Doppler, contrast enhanced ultrasound (CEUS) and shear wave elastography (SWE). Doppler and CEUS techniques offer benefit in terms of AKI diagnosis and in identifying patients at risk. In addition, through the demonstration of altered flow or impaired perfusion, these techniques provide information on the pathophysiology of AKI, offering potential for targeted intervention. Renal SWE, an emerging technique, assesses tissue stiffness potentially allowing exploration of the role of venous congestion in the pathogenesis of AKI.

Summary: Ultrasound continues to demonstrate great promise in the diagnosis and management of AKI, offering a noninvasive means to diagnose perfusion deficits and assess response to treatments. Further research, with standardization of techniques, may allow multifaceted renal ultrasound assessment in the critically ill for more accurate diagnosis and tailored intervention in AKI.