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

The workup of acute kidney injury and/or low urine output frequently warrants the use of renal genitourinary ultrasound. Whereas renal GU ultrasound has traditionally been performed as a consultative service by sonographers and radiologists, our paper defines an evidence-based protocol for point-of-care renal GU ultrasound image acquisition. Our multidisciplinary group has developed a specialty-agnostic renal GU point-of-care ultrasound image acquisition protocol.

This protocol includes indications, limitations, patient positioning, transducer selection, and image optimization. Our protocol simplifies and standardizes the approach to bedside kidney and GU ultrasound, decreasing the need for consultative ultrasonography and expediting diagnosis. To begin, position the patient in supine.

Apply the gel directly to the ultrasound probe to enhance scanning efficiency before imaging, then position the probe on the patient's right flank aligned with the mid-axillary line with the indicator pointing towards the head. Adjust the probe until the right kidney is clearly visible in its maximum longitudinal view. To measure the long-axis diameter of the kidney, center the kidney in the image and select Freeze.

Then, measure the kidney's height and click Save. After centering on the right kidney, rotate the probe 90 degrees counterclockwise until the probe marker faces anteriorly, presenting the kidney in the transverse view. Adjust the probe until the right kidney is displayed in its largest size in the transverse plane.

To begin, position the patient in supine. Apply the gel directly to the ultrasound probe before capturing each image, then place the probe just above the pubic symphysis with the indicator pointing toward the patient's right side. Adjust the depth until the bladder is centered in the middle third of the screen.

After that, adjust the gain setting until the bladder lumen is grossly anechoic and the tissue plane directly posterior to the bladder is slightly hyperechoic. Then sweep through the bladder from the cranial end to the caudal end to visualize the entire structure. Focus the view on the bladder's largest dimension and select Freeze to capture the image, then measure the anterior, posterior, and lateral-to-medial diameters of the bladder.

Click Save to store the measurement. While maintaining the transverse view of the bladder, rotate the probe 90 degrees clockwise until the marker faces cranially, revealing the kidney in the sagittal plane.