From the Guidelines
Renal ultrasound is ordered for chronic kidney disease (CKD) patients to evaluate kidney size, structure, and potential causes of kidney dysfunction, as it provides valuable baseline information about kidney morphology and can detect obstruction of urinary flow, which might require intervention 1. The test helps identify structural abnormalities such as kidney atrophy, hydronephrosis, polycystic kidney disease, masses, or stones that may contribute to or explain the patient's CKD. Some key points to consider when ordering a renal ultrasound for CKD patients include:
- The ability to detect hydronephrosis and evaluate renal size and morphology, which can help differentiate between acute kidney injury (AKI) and CKD 2
- The non-invasive nature of the test, which avoids contrast agents that could further damage compromised kidneys, making it safer than CT scans for CKD patients
- The potential to guide treatment decisions, such as referral to urology for obstruction or adjustment of medication regimens based on the underlying cause of kidney disease
- The importance of considering the patient's individual risk factors, such as a history of stones or obstruction, renal artery stenosis, frequent urinary tract infections, or family history of autosomal dominant polycystic kidney disease, when deciding whether to order a renal ultrasound 3 For CKD patients, renal ultrasound is typically ordered at initial diagnosis to establish baseline kidney characteristics and may be repeated if there is unexpected worsening of kidney function or to monitor known structural abnormalities. It is worth noting that the low impact on management does not support the use of US for routine surveillance of CKD, and US may be indicated when there is a prior history of stones or obstruction, renal artery stenosis, frequent urinary tract infections, or family history of autosomal dominant polycystic kidney disease 3.
From the Research
Reasons for Ordering Renal Ultrasound for CKD Patients
- To evaluate morphological changes and patterns of vascularization in the kidneys, contributing to CKD diagnosis and follow-up of its progression 4
- To measure longitudinal diameter and cortical thickness, and evaluate renal echogenicity and urinary tract status 4, 5
- To assess parenchymal perfusion and patency of veins and arteries using color Doppler, and to diagnose renal artery stenosis using spectral Doppler 4, 5
- To evaluate renal resistive indexes (RIs), which reflect vascular compliance and have been proposed as independent risk factors for CKD progression 4
- To screen patients at risk for CKD and to evaluate CKD progression 4, 6, 7
Benefits of Renal Ultrasound
- Non-invasive and non-ionizing radiation 7
- Generates real-time images, making it ideal for initial radiographic testing 7
- Enables assessment of both structural and functional aspects of kidneys 7
- Rapidly growing in accessibility, with handheld formats available for bedside examinations 7