MRI Guide: The Kidney

The kidneys are a blood-filtering powerhouse. They are vital to extracellular fluid regulation, excretion of waste and toxins, and hormone production. According to research, 2.8 million UK adults have chronic kidney failure (CKF), 1 million of them are unaware they have this disorder. There are different causes of CKF and it can be difficult to identify CKF without an in-depth assessment of the kidneys. Various diagnostic tools can be used to provide a better picture of your kidney function and help lead doctors to a potential diagnosis.

However, not all kidney-related issues result in CKF. Abnormal cell growth or tumours can form in the kidneys restricting blood flow or overall kidney function. If you are experiencing signs of kidney malfunction, your urologist may order an MRI. This tool can identify any abnormalities that could be contributing to the symptoms.

Continue reading as we discuss a kidney MRI procedure, the problems it can detect, and why the procedure might be performed.

What is a Kidney MRI?

A magnetic resonance imaging scan (MRI) is a non-invasive diagnostic tool used to capture images of a specific structure, organ, or area of the body. During a kidney MRI scan, the machine will take images across three planes:

Axial - From top down
Sagittal - From one side to the other
Coronal - From front to back

Each image–called a slice–is an image of the kidney as the machine moves from one side of the plane to the other. This allows the computer to create a three-dimensional recreation of your kidney. A radiologist can then identify any abnormal cell growth, tumours, swelling, or signs of infection.

How is a Kidney MRI Done?

A kidney MRI scan will usually take approximately 10–30 minutes. However, the procedure can take up to 2 hours. The procedure will include:

Changing Clothing
You will be brought to a private room to change into a hospital gown. Some clinics allow patients to wear their loose-fitting clothing, each will have its policies. Be sure to remove any metal and jewellery as metallic items can interfere with the results of the scan.
Administering Contrast Material
Several kidney MRI scans require a contrast material that will need to be administered through an IV. This will highlight certain areas of the kidney, allowing the radiologist to get a better understanding of what is occurring in your kidneys. It can take time for the material to collect in your kidneys before the scan can begin.
Beginning the Scan
You will be instructed to lay down on the MRI table, the radiographer may use pillows or straps to ensure you remain in the correct position. As the table slides you into the hollow tube of the machine, you will hear loud banging noises. This is to be expected.
Remaining Still
Although the machine will be loud, it is important to stay as still as possible. Any sudden movements can affect the results of the scan causing a lengthier procedure.
Removing Contrast IV
Once the scan is complete and the radiographer is satisfied with the quality of the images, your IV will be removed.
Returning to Everyday Activities
Since this is a non-invasive procedure there is no necessary recovery after the procedure. You may feel a little dizzy from laying down for a prolonged period.

Some patients who suffer from anxiety or claustrophobia may be administered a mild sedative before the procedure. If this is the case, you cannot operate a vehicle. Therefore an alternate method of transport will need to be arranged.

Why Would A Urologist Order an MRI?

If you are experiencing signs of renal distress or failure your urologist may order an MRI. Some of these symptoms include:

Swellings of extremities
Back pain around the kidneys
Shortness of breath
Blood in stool
Fatigue or drowsiness
Changes in the frequency of urination

An MRI will be able to show if the cause of your symptoms is due to lack of blood flow, abnormal growths, or–if applicable–possible transplant rejection.

Can MRI Detect Kidney Problems?

An MRI can be used to see:

Restricted blood flow
Tumours
Lymph nodes
Diseased vs normal tissue
Different types of tissue

Radiologists can use MRI images to identify abnormalities in these soft tissues of the kidney. Their findings in conjunction with various physical symptoms can be used to diagnose possible kidney problems.

Is Contrast Material Hard on Kidneys?

The contrast material used, usually gadolinium-based, is mildly radioactive. It allows clearer imagining for certain types of tissue in an MRI scan. It is a safe procedure and complications related to contrast dyes are rare.

In rare cases–less than 2 per cent–the contrast dye can cause nephropathy or the deterioration of kidney function. The effects can be seen 48-72 hours after the dye had been administered. Although frightening this damage can be reversed.

How to Prepare For a Kidney MRI?

Before your procedure, you can expect to fill out a health questionnaire. It is important to identify if you have:

Metal implants - such as screws, pins, stints, or artificial joints
Implanted medical devices - such as a pacemaker or defibrillator
Allergies - particularly to the contrast material or any other medication

You should also inform the clinic if you are pregnant or nursing. Studies have shown no connection between pregnancy and birth defects. However, it is important to provide a comprehensive medical history.

It is not necessary to fast before the procedure. In some instances, your doctor may advise you to drink plenty of fluid before the procedure.

The Bottom Line

An MRI is a powerful diagnostic tool that can be integral in identifying potential kidney problems, kidney failure, or even kidney cancer. By providing additional insight, an MRI scan can help doctors prescribe an accurate treatment plan for managing possible kidney disorders.

If you have additional questions, contact us. Our team is here to provide you with any information you may need. Or if you are ready to avoid the NHS wait times, you can schedule an appointment at one of our centres in as little as 5 working days.

Kidney MRI