Point-of-Care Kidney and Genitourinary Ultrasound in Adults: Image Acquisition

Summary

Point-of-care ultrasound (POCUS) of the renal and genitourinary (renal-GU) system can help to screen for certain causes of kidney dysfunction. However, despite its clinical utility, renal-GU POCUS remains underutilized due to a lack of training among clinicians. To address this gap, this article describes renal-GU image acquisition and interpretation.

Abstract

A range of conditions involving the kidneys and urinary bladder can cause organ-threatening complications that are preventable if diagnosed promptly with diagnostic imaging. Common imaging modalities include either computed tomography or diagnostic ultrasound. Traditionally, ultrasound of the kidney-genitourinary system has required consultative teams consisting of a sonographer performing image acquisition and a radiologist performing image interpretation. However, diagnostic point-of-care ultrasound (POCUS) has recently emerged as a useful tool to troubleshoot acute kidney injury at the bedside. Studies have shown that non-radiologists can be trained to perform diagnostic POCUS of the kidneys and bladder with high accuracy for a set number of important conditions. Currently, diagnostic POCUS of the kidney-genitourinary system remains underused in actual clinical practice. This is likely because image acquisition for this organ system is unfamiliar to most clinicians in specialties that encounter acute kidney injury, including primary care, emergency medicine, intensive care, anesthesiology, nephrology, and urology. To address this multi-specialty educational gap, this narrative review was developed by a multi-disciplinary group to provide a specialty-agnostic framework for kidney-genitourinary POCUS image acquisition: indications/contraindications, patient positioning, transducer selection, acquisition sequence, and exam limitations. Finally, we describe foundational concepts in kidney-genitourinary ultrasound image interpretation, including key abnormal findings that every bedside clinician performing this modality should know.

Introduction

Acute kidney injury (AKI), resulting from a variety of etiologies, is a frequent medical diagnosis identified in hospitalized patients. AKI precipitates an abrupt decrease in kidney function that leads to an accumulation of extracellular fluid, urea, and other nitrogenous waste products, along with the dysregulation of electrolytes. Moreover, the diagnosis of AKI portends worse short-term and long-term outcomes and is associated with the consumption of greater healthcare resources¹. According to the United States Renal Data System (USRDS), among Medicare Fee-For-Service beneficiaries in 2020, the rate of hospitalization with AKI was 62 admissio....

Protocol

All procedures performed in this study involving human participants were in accordance with the ethical standards of the Duke University Health System institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Images included were performed on the authors themselves for normal images and as part of routine educational ultrasound scans done for teaching purposes for positive images, with preceding consent per institutional standards. Patients were incl.......

Discussion

AKI commonly manifests in critically ill hospitalized patients, amplifying the risk of mortality. To proficiently execute the steps outlined above and differentiate normal from pathologic findings, a comprehensive understanding of normal anatomy and ultrasonographic appearances is essential, along with precise adherence to the protocol's specific steps.

Critical anatomy/steps in the protocol
Kidney- The kidneys are retroperitoneal organs that lie in an obliq.......

Materials

Name	Company	Catalog Number	Comments
Curvilinear Transducer	Philips	C5-2 USB	2-5 MHz, also called the abdominal probe
Curvilinear Transducer	SonoSite	C5-1	1-5 MHz, also called the abdominal probe
Edge 1 ultrasound machine	SonoSite		Used to obtain a subset of the Figures and Videos
Phased-Array Transducer	Philips		1-5 MHz, also called the cardiac probe
Phased-Array Transducer	SonoSite	P5-1	1-5 MHz, also called the cardiac probe
Ultrasound system	Philips	Affiniti30	Used to obtain a subset of the Figures and Videos