This summary was prepared by Dr Felicity Goodyear-Smith, Goodfellow Unit, Department
of General Practice & Primary Health Care, University of Auckland and Dr Stephen
Wood, Radiology Registrar, Auckland.
Renal Tract Ultrasound
About Renal Tract Ultrasound
Use of renal tract ultrasound:
- Ultrasound is a very good method for investigating a wide range of renal tract abnormalities.
- Abnormalities that can be visualised include some structural abnormalities, size
differences, hydronephrosis, renal parenchymal abnormalities, scarring, renal masses
and renal cysts.
- Use of colour Doppler scanning means the renal vessels can also be examined - a
specialist procedure only.
Specific indications:
- Renal colic: Usually CT or IVU. However US (with a plain radiograph) offers an alternative,
particularly in pregnancy or repeated investigations in a young person where radiation
dose is a potential concern.
- Urinary infection: Recurrent lower UTIs in adult females do not usually require
imaging. Where imaging is clinically indicated (such as in recurrent upper UTIs
or adult males) US can be useful to show renal size, scarring, collecting system
dilatation, residual bladder volume and to assess for complications such as obstruction
or renal / peri-renal abscesses. Ultrasound is the first line investigation for
UTI in children (a micturating cystogram is probably also necessary).
- Haematuria: US is the first line investigation in haematuria that relates to probable
renal parenchymal disease (such as acute renal failure). Usually use IVU with cystoscopy
if neoplasia is suspected.
- Renal masses: US can assess solid vs cystic masses, the vascularity of the mass
or collecting system dilatation.
- Renal failure: Use US to exclude obstruction; assess renal size (bilateral small
kidneys may suggest irreversible disease); check for calculi or polycystic kidney
disease.
- Prostatic enlargement: US can assess the -size of the prostate and the bladder residual
volume.
Advantages of renal ultrasound:
- Painless and non-invasive.
- Does not involve exposure to radiation.
- Requires little preparation.
Disadvantages of renal ultrasound:
- The nature of ultrasound images means the renal tract urothelium detail is limited.
- The image quality may be reduced by obesity, overlying bowel gas or inability of
the patient to co-operate with positional and breath holding instructions.
- If vesicoureteral reflux is the concern, it is better to perform a micturating cystourethrogram.
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Images from Renal Ultrasound
Click on these images for an enlarged view - opens in a separate window which you
will need to close.
Normal Kidney Ultrasound |
Transitional Cell Carcinoma - This Ultrasound Goes with the X-ray of the Same Title
in the IVU Section |
Clot in Bladder from Bleeding Renal Cell Carcinoma - Urine Shows as Black |
Mass in Bladder |
Renal Cell Carcinoma
at Mid Pole of Kidney |
Staghorn Kidney - Echogenic Calculus with Shadowing |
Multiple Renal Cysts in Right Kidney |
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Patient Information
This patient information is available
as a PDF file from which you may print copies - you will need an acrobat reader.
Information for the patient on renal ultrasound:
- This examination provides images of your kidneys and bladder.
It can be used to:
- detect a mass, cyst, kidney stone, or obstruction to the flow of urine; or
- determine kidney size and shape.
The scan is safe and painless and no ionising radiation is involved.
How it works
A transducer passed over your kidneys emits sound waves that, like sonar, bounce
off your kidney, transmitting a picture of the organ which is then displayed on
a video screen.
Preparation:
- There is no preparation necessary for this examination, although a full bladder
is usually required prior to the scan.
- Medications can be taken prior to the scan.
The procedure:
- The procedure usually takes about 30 to 45 minutes. Test time may vary due to specific
doctor requests.
- In order to obtain quality images, a water-soluble gel is placed on your skin to
act as a medium for the transducer.
- The transducer is a plastic device which is placed over the abdominal area and moved
back and forth to obtain the images necessary to answer your physician's questions.
- Positioning may cause some minor discomfort, as may coolness of room or equipment.
Possible problems
In very obese people, the outline of the kidneys may be obscured by fatty tissue.
Similar problems can be encountered by bowel gas obscuring the kidneys.
After-care:
- After the test, you may resume
all normal activities.
- Your attending doctor will discuss the results of your ultrasound examination.
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