A kidney, or renal, ultrasound is a common, non-invasive imaging technique used to visualize the structure of the kidneys and surrounding tissues. This method utilizes high-frequency sound waves that travel through the body and reflect off internal organs. A computer captures these returning echoes and converts them into real-time images displayed on a monitor, providing a detailed view without using ionizing radiation.
Why the Scan is Performed
Physicians often order a renal ultrasound to investigate unexplained pain in the flank or back region that may suggest a problem with the urinary tract. The technology is effective for detecting kidney stones, showing their size and location within the collecting system. The scan can also identify abnormal growths, such as masses, cysts, or tumors, developing on or within the kidney tissue.
The procedure is also used to evaluate the size, shape, and position of the kidneys, which is helpful when monitoring chronic conditions like kidney disease or hypertension. It allows doctors to look for signs of a urinary tract obstruction or an abscess resulting from a kidney infection. By providing visual confirmation of these issues, the ultrasound guides further diagnostic steps or treatment planning.
Preparing for the Examination
Patients are often instructed to wear loose-fitting clothing that allows easy access to the abdomen and lower back area. Depending on the specific structures the doctor needs to view, a period of fasting may be required for several hours before the appointment.
Fasting minimizes gas and food residue in the digestive tract, which can block the path of the sound waves and obscure the view of the kidneys. Patients are commonly instructed to drink several glasses of water an hour or two before the scan and to hold the urine. A full bladder pushes surrounding bowel loops out of the way, significantly improving the visualization of the bladder and the lower parts of the ureters.
The Procedure Step by Step
Upon arrival, the patient is typically asked to change into a gown and then is positioned on an examination table, usually lying flat on their back. The sonographer, a specially trained technologist, applies a clear, water-based gel directly onto the skin of the patient’s abdomen and flanks. This acoustic gel eliminates air pockets between the skin and the imaging device, ensuring the sound waves pass effectively into the body.
The technologist then presses a small, handheld device called a transducer firmly against the skin and moves it across the area being examined. Patients will feel a slight pressure from the transducer, which is necessary to maintain good contact and capture detailed images. The transducer emits the sound waves and receives the returning echoes, generating the images for the technologist to review.
To get comprehensive views, the technologist may ask the patient to take a deep breath and hold it briefly. This action pushes the kidneys slightly downward, making them easier to visualize beneath the rib cage. The patient may also be asked to turn onto their side to allow the transducer to scan the flank area from different angles. The entire procedure is generally comfortable and takes approximately 20 to 30 minutes to complete.
What Happens After the Ultrasound
After the images are collected, the technologist wipes the acoustic gel residue from the skin. Since the ultrasound is a non-invasive procedure, the patient can typically get dressed and resume all normal activities right away. There are no restrictions or recovery time necessary following the examination.
The images recorded during the scan are not interpreted by the technologist; instead, they are sent to a radiologist, a physician trained to interpret medical images. The radiologist carefully analyzes the size, shape, and echo patterns of the kidneys and surrounding structures for any abnormalities. They then compile a detailed report summarizing their findings.
This official report is then sent to the doctor who originally ordered the ultrasound, usually within a few days. The patient will need to schedule a follow-up appointment with their physician to discuss the results and determine the next steps. Depending on the findings, the doctor may confirm a diagnosis, adjust a treatment plan, or recommend additional diagnostic testing.