Bone marrow edema on an MRI: fracture line or not

The words next to it

Words you may see beside bone marrow edema on a report, and what each one changes.

Edema-like signal

Newer wording for the same finding. Only a microscope can confirm true edema, so many radiologists name the signal they see instead.

Bone bruise or contusion

Edema from an injury that didn't break the bone. On the images it looks patchy and uneven.

Linear low signal or fracture line

A dark line through the edema that shows on every image type is the break itself. Thin lines running across the direction of load, with a lot of edema around them, fit a stress fracture.

Diffuse

Spread over a wider area of the bone. Early avascular necrosis (bone losing its blood supply), inflammation or a stress fracture can all look like this, so your history counts for a lot.

Transient osteoporosis or bone marrow edema syndrome

Painful edema with no injury or other cause found. It turns up most often in the hip, then the knee, ankle and foot.

Ligament or meniscus tear

In the knee, edema often comes with these injuries, so it points the radiologist toward small tears that are easy to miss.

How long bone marrow edema takes to settle

The cause sets the timeline. Edema from a bruise or overuse usually clears on MRI in about 3 months, and the pain often eases sooner, around 6 weeks. So a scan done soon after you feel better can still show it. Bone marrow edema syndrome usually settles on its own over 3 to 18 months.

In the hip, three conditions can look alike at first and end very differently. Transient osteoporosis usually settles on its own, avascular necrosis is permanent, and a subchondral insufficiency fracture may heal fully or get worse.

If you're wondering about cancer

Solid tumors can cause edema in the marrow around them. Radiologists work to tell the tumor itself apart from that edema, and one imaging review calls the difference "crucial" for the surgeon. If your report names a mass or lesion, that's the finding to ask about.

If the person scanned already has a cancer diagnosis, how to read this edema is the oncologist's call.

Questions to ask the doctor

• Did the radiologist see a fracture line, or only edema?
• What do you think caused it: an injury, overuse, arthritis, or something else?
• How long should mine take to settle, given the cause?
• Should I limit weight or activity on this bone while it heals?
• Is the edema the main finding, or a reaction to something else on the report?
• Would a repeat MRI change anything, and if so, when?

Often on the same report

• Bone bruise

  Blood trapped under the surface of the bone after a hit or a twisting injury, without the bone breaking. It takes much more force than a skin bruise and can take longer to heal. Bone bruises are very common with ACL tears in the knee.

• Stress fracture

  A break in the bone caused by repeated stress over time, rather than one sudden injury. It's more likely after a sudden jump in activity, with running, jumping, or marching, or in bones already weakened by osteoporosis.

• Osteoarthritis

  Arthritis where the smooth cartilage that pads the ends of the bones breaks down and becomes rough, and bumps of extra bone (bone spurs) may grow. It's the most common type of arthritis, usually in the hands, knees, hips, neck, and lower back, and it usually gets worse slowly.

• Avascular necrosis

  Bone death caused by poor blood supply to part of a bone. Over time the bone can collapse and the nearby joint can wear down. It's most common in the hip and shoulder, and causes include steroid medicines, heavy alcohol use, and fractures or dislocations near a joint.

• Hyperintense

  Brighter than the tissue around it on an MRI image. It describes how an area looks, not what it is, since swelling, extra fluid, and other changes can all look bright depending on the type of image.

• Joint effusion

  Extra fluid built up inside a joint. It can come from an injury such as a ligament tear or fracture, arthritis, gout, or infection. A small amount can be seen in healthy joints, while a larger amount usually points to a problem.

Questions people ask

What does bone marrow edema on MRI mean?

It means the MRI picked up extra fluid in the bone marrow, the soft tissue inside a bone. It looks dark on T1 images and bright on the fluid-sensitive T2 and STIR images.

Is bone marrow edema painful?

It can be, and pain in or around the bone is the main symptom. Some people have no symptoms and learn about it from an MRI done for something else. In osteoarthritis, people with pain were 3.31 times as likely to have it as people with the same X-ray grade.

What is subchondral bone marrow edema?

Subchondral means just under the cartilage that lines a joint. Edema there can come with wear, as in osteoarthritis, or with repeated stress, where it's often wedge-shaped with its widest part where the load is greatest. Bone marrow edema syndrome shows up there too, as a wide area with blurry edges, mostly in the knee and hip.

Can an X-ray show bone marrow edema?

No. Plain X-rays and CT scans don't show it, and MRI is the scan that finds it. An X-ray can still hint at a cause, such as osteoarthritis or advanced avascular necrosis.

Other phrases explained: Pulmonary nodule · Ground-glass opacity · Aortic atherosclerosis · Schmorl's node