Ultimate Guide to Knee MRI Scan

The knee is susceptible to various degenerative disorders and injuries as it is arguably the most stressed joint in the human body.

With the superior ability of an MRI to discriminate soft tissues, it’s a common imaging technique for visualising the knee joint to diagnose knee issues.

But what should you expect when going for a MRI of the knee? This article will answer this question. 

In the article, we’ll examine everything you need to know about knee MRI scan, including how to prepare for the scan and how to read the MRI scan results.

The knee is susceptible to various degenerative disorders and injuries as it is arguably the most stressed joint in the human body.

With the superior ability of an MRI to discriminate soft tissues, it’s a common imaging technique for visualising the knee joint to diagnose knee issues.

But what should you expect when going for an MRI of the knee? This article will answer this question. 

We will examine everything you need to know about MRI of the knee, including how to prepare for the scan and how to read the MRI scan results.

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How does a knee MRI scan work?

A knee MRI (magnetic resonance imaging) scan is a non-invasive imaging technique that uses radio waves and a powerful magnetic field to create clear images of the internal structures of the knee joint.

The knee is a complex joint with various structures, including:

• Bones
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• Cartilage
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• Ligaments
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• Tendons
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• Synovial membrane
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• Blood vessels

An MRI of the knee is used to evaluate these structures for any issue without cutting into the knee.

After the knee MRI scanner creates images of the knee’s internal structures, your doctor examines the images to see if anything is amiss. This makes an MRI of the knee invaluable in diagnosing and treating complicated knee injuries.

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What problems can an MRI of the knee detect?

An MRI of the knee can detect several problems in the structures of the knee joint, including

• Meniscal tears (like medial and lateral meniscus injuries)
• Ligament injuries (like anterior cruciate ligament tear, medial collateral ligament tear, etc.)
• Cartilage damage (like osteoarthritis, etc.)
• Subtle bone fractures, stress fractures, and bone bruises

Chondromalacia patellae is one common knee issue that an MRI of knee detects. Chondro means cartilage, malacia means breakdown, and patellae means kneecap. 

So, Chondromalacia patellae (aka Patellofemoral pain syndrome or runner’s knee) refers to the softening or breakdown of the cartilage underneath the kneecap.

When it happens, the cartilage does not provide sufficient cushioning as the undersurface of the patella rubs against the thigh bone, resulting in an aching pain in front of your knee, behind your kneecap.

Another knee issue that an MRI of the knee detects is tibial plateau fractures. The tibial plateau is the flat top portion of the larger lower leg bone (tibia). This flat top is covered with cartilage and forms the lower part of your knee joint.

A tibial plateau fracture is a crack or breaking of the upper part of the tibia that reaches the tibial plateau and injures the cartilage covering it. 

A tibial plateau fracture is caused by falls and accidents and can result in very severe pain and swelling.

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Can an MRI miss tears in the knee?

MRIs are highly sensitive (hence, accurate) imaging techniques. However, there can be instances where an MRI examination fails to detect certain tears in the knee.

The factors affecting the accuracy of MRIs in detecting tears in the knee include:

Size and location of the tear

Smaller tears, especially those involving tiny structures like meniscal fibres, are more challenging to detect. Studies show that tears in the peripheral posterior horns of the meniscus can be easily missed on MRI. 

The sensitivity of MRIs for diagnosing a meniscal tear is significantly higher when the tear involves over one-third of the meniscus or the anterior horn and lower for meniscal injuries in the posterior horn.

Partial tears

When a tear is partial and does not disrupt the tissue continuity enough, it may be difficult for an MRI of the knee to detect. This is why partial ACL ruptures can be missed by knee MRIs.

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How do I prepare for a knee MRI scan?

There is not much in preparing for an MRI of a knee scan. Your healthcare provider or the imaging centre will provide specific instructions for your MRI. It is important that you follow these instructions carefully. 

After booking your procedure, talk to your doctor about any medical conditions or allergies. Also, let them know if you have implants or tattoos or if you’re claustrophobic.

Before the procedure, you’ll have to remove all metallic objects, such as jewellery and watches, including clothing with metallic elements (like metal fastenings and zippers). 

Many centres will make you change into a hospital gown to ensure that you do not go into the machine wearing clothing with metal parts.

Can I take anything before a knee MRI?

Before an MRI of the knee, you can take food, drink, or even your medication as usual, except if your healthcare provider tells you not to.

Always follow your healthcare provider’s instructions regarding whether you can take anything before a knee MRI. 

Sometimes, doctors okay food, drink, or medication intake before an MRI. But in certain cases, they may instruct patients not to take anything for about four hours before the scan. 

Can I get a knee MRI if I have metal implants?

Your doctor will assess the specific condition surrounding your implants and determine your suitability for the MRI of the knee. But you may be able to get an MRI of the knee with metal implants.

Doctors look at different factors when determining the suitability of patients with implants for a knee MRI. These include the type of implant and the scanner strength.

While metallic objects can interfere with the magnetic field of an MRI machine, many metallic implants (like titanium) are MRI-compatible. 

Also, while higher strength MRIs (like 3T MRIs) pose more risk to patients with implants, lower strength (1.5T) MRIs may be fine for some metal implants. 

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What is the procedure for conducting a knee MRI scan?

The procedure for conducting an MRI knee scan typically involves the following:

Removal of all metals

You’ll be instructed to remove all metals and clothing with metallic parts. Some centres will provide you with a metal-free gown to change into.

Positioning on the MRI table

You’ll be positioned on the sliding table of the MRI machine. Your knee may be secured with a brace or cushioned device to keep it in a specific position during the procedure.

Insertion of an IV line

If your MRI involves using a contrast agent, a staff member will insert an IV line into a vein in your arm. The line will be used to inject the contrast agent during the procedure. 

Entering the MRI machine

The operator will then slide you (leg-first) into the machine, ensuring the knee to be examined is positioned where it is optimally exposed to the magnetic field and radiofrequency pulse.

Scanning

The MRI machine then captures images of your knee. The knee is exposed to a strong magnetic field, causing protons in hydrogen atoms in the knee joint to align with it. 

Radio waves are directed at the aligned protons to disrupt their alignment. When the radio waves are removed, the protons will return to their original alignment and release energy in the process. This MRI machine detects the energy, and the connected computer uses it to create detailed images of the knee joint. 

Is a knee MRI painful?

An MRI of the knee is a painless procedure. You won’t feel any pain from the magnetic field or radio waves the scanner uses.

However, the procedure requires lying in one position for a long time, and you may feel sore from this. Also, if your MRI involves using a contrast material, you may feel some discomfort at the injection site. 

How long does a knee MRI take?

A knee MRI takes about 30 to 60 minutes. So, the procedure takes longer than an X-ray or CT scan.

Will I be given an injection during a knee MRI?

You’ll be given an injection during a knee MRI scan if your healthcare provider determines that a contrast agent is needed to enhance the visibility of certain structures within the knee joint. This is because the contrast material is administered via an injection into the arm. 

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How do you read a knee MRI scan report?

Reading the results of an MRI of the knee should be left to professionals. Knee MRI scan images are usually created in three planes (coronal, sagittal, and axial) to allow for an examination of the knee joint from different angles.

The coronal view looks at the knee from front to back, the sagittal view looks at it from the sides, and the axial view looks at it from the top down.

Coronal MRIs

When looking at the coronal plane, you’ll see the patella at the centre. As you go deeper, you’ll see the quadriceps tendon and patellar tendon below it. 

Further down, you’ll see the tibiofemoral joint. The medial meniscus and lateral meniscus come into view, as well as the iliotibial band on the side. 

Going further, you’ll see the superficial medial collateral ligament on the medial aspect of the knee along the tibia. The ACL becomes clearer as you go deeper into the knee. 

On the lateral side of the knee, you’ll start to see the fibular collateral ligament. Going deeper, you’ll see more of the posterior cruciate ligament and the meniscal attachments. 

Moving more to the posterior aspect of the knee, you’ll begin to see the biceps femoris and the popliteal artery.

These are the main structures that clinicians look at in coronal MRIs. Most of the time, they look for meniscal injuries in either the medial meniscus or the lateral meniscus.

Sagittal MRIs

Starting from the lateral aspect of the knee, you’ll see the fibular head and the biceps femoris attachment on it. Coursing more lateral, you’ll start to see the lateral meniscus.

Going deeper within the joint, you’ll see the cartilage surfaces. The gastrocnemius tendon on the outside of the knee becomes visible. You can also see the posterior and anterior horn of the lateral meniscus. Close to the centre of the knee, you’ll see the articular cartilage on the lateral femoral condyle. 

You’ll also start to see the articular cartilage on the lateral aspect of the trochlear groove.

At the centre of the knee, the patellar comes into view. You’ll see the patellar tendon, the articular cartilage of the patella, and the ACL. 

You’ll also see the PCL, where it attaches to the femur and courses down to the tibia. Moving into the far medial aspect, you’ll see the hamstring tendons.

Clinicians examine these structures for any abnormal signals or irregularities.

Axial MRIs

The axial view looks at the knee from the top down. Taking axial planes of the knee on the tibia, you’ll see the tibial tubercle, the fibula, and neurovascular bundles.

Going closer to the joint, you’ll see the proximal tib/fib joint start to form. The popliteus muscle also comes into view, and the popliteal artery posterior to it. 

Closer to the joint, you’ll see the outline of the menisci. Clinicians look here to see whether there’s any small radial tear that the sagittal and coronal views may not show.

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What are the benefits of a knee MRI scan?

The benefits of a knee MRI are: 

• It produces high-res images that allow visualisation of soft tissues like ligaments, tendons, cartilage, etc.
• It is highly sensitive to diagnose ligament and tendon injuries.
• It helps detect meniscal tears, including their location, size, and configuration.
• It can identify abnormalities in the bones of the knees, such as fractures, infections, or degenerative changes.
• It helps detect inflammatory conditions that affect knee joints, such as synovitis.
• Unlike arthroscopy, a knee MRI is a non-invasive way of seeing what’s happening inside the knee.
• Unlike CT scans, it is a radiation-free imaging technique.

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What are the limitations of knee MRI?

While a knee MRI has many benefits, it comes with a few limitations. These include:

• MRI images are affected by artefacts, which may mimic or obscure pathology.
• It has limitations in assessing certain details of bone structures.
• The sensitivity of MRIs often causes overdiagnosis—identifying conditions that may not require intervention.
• An MRI of the knee does not provide information about the functional aspect of a knee joint, such as dynamic movements.
• The more common closed MRI machine may cause anxiety in some people, particularly those who are claustrophobic.
• An MRI is relatively expensive compared to CT scans.

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How to find knee MRI scan “near me”

When going for a knee MRI scan, it’s practical to choose an imaging centre near you, as that makes it more convenient to schedule and attend imaging appointments.

GetScanned is the go-to service for finding an MRI imaging centre near you. You simply assess the website and enter your location, and GetScanned will furnish you with a list of the best facilities near you.

With the GetScanned MRI service, finding a knee MRI scan close to your vicinity is easy. The benefits of using GetScanned include:

• Local options: With GetScanned, you can explore the different imaging facilities near you to choose one that meets your preferences in terms of location, convenience, reputation, and budget.
• Appointment scheduling: GetScanned provides real-time availability information for the different MRI imaging facilities near you. So, you can view available appointment slots, making it easy to choose appointment times that suit your schedule.
• Ease of rescheduling: Not only does GetScanned make it easy to book a knee MRI scan appointment, but It also makes it easy to cancel and reschedule an appointment. You simply look through your preferred facility’s available appointment slots and pick one that suits you.
• Post-booking support: GetScanned does not stop at connecting you to an MRI facility near you. GetScanned also works with the facility you choose to ensure you have a seamless experience.

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Cost of knee MRI scan

In the UK, the average cost of a private MRI scan for one body part is £395.

However, when searching “knee MRI scan cost near me,” you may find costs starting at £200 and reaching about £950. 

The cost of a knee MRI scan can vary significantly depending on several factors, including location, the imaging centre, whether the scan involves using a contrast agent, and medical insurance coverage.

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Conclusion: Diagnose knee issues with precision using magnetic imaging resonance 

Have you been feeling pain in your left knee? Your doctor will probably recommend an MRI of the knee. A knee MRI will provide detailed images of the knee joint to help diagnose a range of conditions, from small tears to complex knee injuries.

The quality of MRI images is crucial to accurate diagnoses. It can be influenced by many factors related to the imaging facility you use. This is where GetScanned comes in!

GetScanned is a marketplace for medical scans. We connect you with state-of-the-art imaging facilities that will give you incredibly detailed MRI images for accurate diagnoses of any knee problem you may have.

Simply enter your postcode, and we’ll give you a list of the best medical facilities near you for your knee MRI. After you book your MRI, we’ll work with the facility to ensure you have a seamless experience.

Book your knee MRI via GetScanned today!

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FAQs

Below are the answers to some frequently asked questions about knee MRI: 

1. Is MRI safe for knee pain?

The powerful magnetic field used in an MRI does not have any known harmful effects (except where metal implants are involved). If you are experiencing pain or swelling in the knee, your doctor will likely recommend a knee MRI scan.

2. Is MRI or CT scan better for knee pain?

An MRI is the best imaging technique for visualising soft tissues. And with the knee joint having several soft tissues that can be culprits for knee pain, the MRI is the best scan to discover the reason for your knee pain, weakness, or swelling.However, because CT scans are quicker to obtain, your doctor may recommend a CT scan (over an MRI) in an emergency situation. Also, because the magnetic field of MRIs affects metallic implants, your doctor may choose a CT scan over an MRI for you if you have certain metallic implants.

3. What are the disadvantages of a knee MRI?

An MRI scan is more expensive than other imaging techniques, and this can be an issue for some, especially if insurance is not comprehensive. MRI scans also take longer (about 30 minutes to one hour), and staying still for that long can be discomforting for patients.MRI scans often require using contrast agents to enhance the visibility of certain structures, and this can cause allergic reactions in some. Lastly, an MRI knee scan is not suitable for everyone, especially people with metallic implants, as the powerful magnetic field used in an MRI scanner may shift metallic implants in the knee. 

4. How accurate is MRI for knee?

In medical imaging, an MRI knee scan is considered a highly accurate and reliable modality for evaluating knee structures and diagnosing knee issues.

5. When is an MRI recommended for knee pain?

Your doctor may recommend an MRI knee scan when you have pain, weakness, or swelling in your knee. For example:

• You experienced a traumatic event such as a sports injury, a fall, or an accident and began experiencing pain in the knee.
• You have pain in your knee that persists after taking over-the-counter pain medication and using conservative treatments like RICE (rest, ice, compression, and elevation).
• You have unexplained swelling or limited range of motion in the knee.