An MRI is the standard scan that healthcare providers recommend to see whether you have torn or damaged a knee ligament like the ACL. Your provider ordered a knee MRI because it will give them the accurate, reliable information they need to diagnose your injury.
Getting a knee MRI is a quick, non-invasive way for your provider to take detailed images of the inside of your knee, and to help them make a treatment plan customized to your condition.
We’ll show you exactly why MRI is the preferred scan for helping to diagnose a torn ACL, along with everything you need to know about getting a knee MRI, and what you can expect from your results. Let’s look at MRIs for diagnosing an ACL tear.
What is an ACL? What does it do?
The ACL, or anterior cruciate ligament, is one of the key ligaments that helps stabilize your knee joint. It connects your thigh bone to your shinbone, and plays a crucial role in keeping your knee steady, especially during activities that involve sudden stops, twists, or changes in direction.
A torn or damaged ACL is a fairly common injury. It often happens while someone is playing sports, whether that may be a high-impact sport, like basketball or soccer, or another activity that puts stress on the knee, like jumping or pivoting.
When your ACL is working properly, it helps control the movement of your knee, preventing it from moving too far forward or twisting in an unstable way. But when an ACL is damaged, you might experience pain, swelling, instability, or a feeling that your knee could give out.
How does a knee MRI show if my ACL is torn or damaged?
A knee MRI scan uses magnetic fields to create highly detailed images of the tissues inside your knee, including the ACL. It lets your provider clearly see soft tissues like ligaments, tendons, cartilage, and muscles, which makes it particularly useful for diagnosing a torn ACL.
During the MRI scan, multiple images of your knee are taken from different angles, and a torn ACL will look a little different from a healthy one: in MRI images, a torn ACL may show signs of fraying, gaps, or complete separation. The detailed visualization helps pinpoint the exact location and the extent of the damage.
How can an MRI tell the difference between a partial ACL tear and a complete ACL tear?
A knee MRI is great at differentiating between a partial tear and complete tear. A partial ACL tear means that only some of the ACL fibers have been damaged, while a complete tear involves the full rupture of the ligament.
In the case of a partial tear, the MRI might show areas where the ligament is still partially intact, with visible fibers holding the knee together, but these fibers may look thinner or irregular, indicating partial damage. A complete tear will often show a distinct gap where the ligament has fully torn apart, with no visible connection between the two ends.
Getting a knee MRI to diagnose an ACL tear
While the vast majority of knee MRIs are quick and stress-free, there are a few things to keep in mind when you get an MRI for an ACL tear, so you’ll be fully prepared for your appointment. Here’s how to get ready, what to expect during the scan, and how your technologist will make you comfortable during the scan.
How should I get ready for my knee MRI appointment?
Be sure to follow your healthcare provider’s instructions for getting ready. It’s a good idea to wear comfortable, loose-fitting clothing, since you might be asked to change into a gown for your scan.
You’ll probably be asked to remove any metal objects, like jewelry, watches, or belts, as these items can interfere with the accuracy of your MRI images. If you have any metal implants, like a pacemaker or surgical pins, be sure to inform your healthcare provider and the MRI technologist beforehand. This helps ensure a safe and effective scan.
In most cases, you won’t need to fast or make any major changes to your routine before the MRI, but it’s always best to confirm any specific instructions with your provider ahead of time.
What happens during a knee MRI scan? How long does it take?
During your knee MRI, you’ll lie down on a table that slides into the doughnut-shaped MRI machine, and your technologist will help you find a comfortable position. The scan itself is painless and non-invasive, but the machine does make some loud noises while it captures images of your knee, like thumping and buzzing sounds.
The entire process typically takes less than 30 minutes from the moment you walk in the door. American Health Imaging has faster scanning MRI technology at most of our centers reducing the time you spend in the MRI by up to 50% to an average scan time of less than 15 minutes.
During that time, you’ll need to stay as still as possible to ensure clear images of your knee. If you feel uncomfortable at any point, you can use an intercom to communicate with your MRI technologist, who will be able to hear you throughout the scan.
Does my entire body go inside the MRI machine for a knee MRI?
For a knee MRI, only your legs need to go inside the MRI machine, while the rest of your body can remain outside the machine. Your MRI technologist will position you on the table so that your knee is in the right place for the scan, and then slowly move your legs into the MRI machine.
If I have knee pain, what can my MRI technologist do to make me comfortable during my knee MRI?
If you’re experiencing knee pain, let the MRI technologist know before the scan begins. They can provide extra padding, adjust your position, or use supports to keep you as comfortable as possible during the scan.
You’ll be asked to hold still during the imaging process, but the technologist can pause the scan, and reposition you as needed. However, this is rarely needed with our faster scanning technology. Please don’t hesitate to speak up if something doesn’t feel right during the scan, as your technologist’s goal is to ensure you have a smooth and comfortable experience, along with accurate MRI images.
Using a knee MRI to guide your treatment options
The images from your knee MRI will give your orthopedic provider a lot of the information they need to diagnose whether you have a torn ACL, so they can make a plan for your care, and monitor the progress of your treatment. Here’s what you need to know about how long your MRI results will take, how your results are analyzed, how your provider uses your results to treat you, and what to know about follow-up imaging.
How long will it take to get my knee MRI results?
After your MRI scan, the images will be reviewed by a radiologist, which is a specialist who interprets MRI scans. The radiologist will write a detailed report, which will be sent to your healthcare provider to discuss with you.
In most cases, it takes about a week to receive your results. Once your results are ready, your provider will schedule a follow-up appointment to go over the findings, and to talk about your next steps.
How will my radiologist analyze my MRI images to identify an ACL tear?
Your radiologist will carefully examine the images from your MRI to look for signs of damage, like fraying, swelling, or gaps in your ACL, which may indicate a tear. The high-resolution images from an MRI allow the radiologist to see soft tissues in great detail, making it easier to identify even small tears.
In addition to checking your ACL, the radiologist may also look at surrounding tissues like the meniscus, cartilage, and other ligaments to see if there are any additional injuries to your knee.
How will my provider use my results to see if I need knee surgery, or physical therapy, or a knee brace?
Once your provider reviews your knee MRI report, they’ll use it to determine the best course of action for your specific injury. If the MRI shows a partial ACL tear, your provider may recommend less invasive treatments like physical therapy or wearing a knee brace to support healing. Physical therapy can help strengthen the muscles around your knee, improve stability, and reduce the risk of further injury.
For more severe or complete ACL tears, surgery might be necessary, especially if you want to return to high-impact activities like sports. Your provider will take into account factors like the severity of the tear, your activity level, and your overall health before recommending surgery. Whether your treatment involves rest, rehabilitation, or surgery, your MRI results are vital for making that decision.
Why did my provider recommend follow-up imaging if I have a torn ACL?
In some cases, your provider might suggest follow-up imaging after your initial MRI, especially if they want to monitor the progress of your injury, or if other parts of your knee are affected.
Your healthcare provider may also recommend follow-up imaging if you’re not responding as expected to treatment, or if they have a concern about how your knee is recovering. This allows your provider to adjust your treatment plan if necessary, ensuring the best possible outcome for your recovery.
How to schedule a MRI appointment with American Health Imaging
Reach out to us at American Health Imaging, and we’ll help you schedule an appointment at an imaging center near you, today.
We’re here to help you get the answers you need.
Frequently Asked Questions
What does an MRI do when diagnosing an ACL tear?
An MRI captures detailed images of the knee, allowing your provider to clearly see the ACL, and determine if it is torn or damaged.
How can an MRI differentiate between a partial and a complete ACL tear?
An MRI can show whether the ACL is partially intact or completely separated, helping your provider determine the extent of the tear.
What should I do to prepare for my knee MRI?
Wear loose clothing, remove metal objects from your body and your clothing, and inform your provider if you have any metal implants.
What happens during a knee MRI scan?
You’ll lie still on a sliding table, and your technologist will move you into the doughnut-shaped machine, which takes images of your knee.
Does my whole body go inside the MRI machine for a knee scan?
No, only your legs need to be inside the machine, while the rest of your body remains outside.
How can I stay comfortable during the MRI if I have knee pain?
Let your technologist know, and they can adjust your position or provide padding to make you more comfortable.
How long does it take to get my MRI results?
It usually takes about a week for your radiologist to review the images and provide a report to your healthcare provider.
How will my MRI results help guide my treatment plan?
Your provider will use the results to determine if you need surgery, physical therapy, or other treatments based on the severity of your ACL injury.