A hip MRI produces detailed images of bone, cartilage, tendons, ligaments, muscles, and the fluid-filled spaces inside and around the hip joint. Unlike an X-ray, which only shows bone, an MRI reveals the full range of soft tissue structures, making it the go-to imaging tool when the source of hip pain isn’t obvious or when early-stage damage needs to be caught before it worsens.
Bones and Early Fractures
MRI can detect bone problems that don’t show up on standard X-rays. Stress fractures are a prime example. These tiny cracks develop from repetitive loading, common in runners and military recruits, and they’re often non-displaced, meaning the bone hasn’t shifted out of position. That makes them nearly invisible on X-ray. On MRI, though, the surrounding bone swelling lights up clearly, allowing a diagnosis weeks before an X-ray would catch it.
MRI is also the most reliable way to detect avascular necrosis (AVN), a condition where blood supply to the femoral head is disrupted and the bone begins to die. In the earliest stage, X-rays look completely normal, but MRI already shows a telltale low-signal band inside the bone. As the disease progresses, MRI tracks the damage through later stages: visible bone changes, then a collapse of the bone surface (measured in millimeters of depression), and eventually full-blown arthritis. Catching AVN early changes treatment options significantly, which is why MRI is ordered when risk factors like long-term steroid use or heavy alcohol intake are present.
Labral Tears
The labrum is a ring of tough cartilage lining the rim of the hip socket. It deepens the socket, helps seal in joint fluid, and stabilizes the ball of the femur. Tears in the labrum can cause clicking, locking, a feeling of the hip “giving way,” and a deep, mechanical pain in the groin area.
MRI can identify labral tears, though its accuracy depends on the type of scan. A standard MRI picks up labral tears with moderate reliability. An MR arthrogram, where contrast fluid is injected into the joint before scanning, fills in the gaps around the labrum and makes tears easier to see. Research comparing the two at high-field-strength scanners found similar sensitivity for labral tears (around 55%), but the arthrogram was notably better at revealing cartilage defects on the socket side, where the cartilage is extremely thin and damage can be hard to spot without contrast filling the defect.
One important piece of context: a study of people with no hip pain found labral abnormalities in 69% of their hips. That means a labral tear on MRI doesn’t automatically explain your symptoms. Your doctor will match the imaging findings with your specific pain pattern and physical exam before recommending treatment.
Femoroacetabular Impingement
Femoroacetabular impingement (FAI) happens when the shape of the hip bones causes abnormal contact during movement. MRI is the primary tool for evaluating the two types. Cam impingement involves a bump or loss of the normal curve at the junction where the femoral head meets the neck, sometimes described as a “pistol grip” shape. Radiologists measure this using the alpha angle, a specific angle taken from images along the femoral neck. An alpha angle above 55 degrees is considered a risk factor, though some people with elevated angles have no symptoms at all.
Pincer impingement is the opposite problem: the socket covers too much of the femoral head. MRI shows the degree of this overcoverage and whether the socket is abnormally deep or tilted. Both types of FAI cause predictable cartilage wear patterns that MRI can map. Cam lesions typically damage the cartilage on the front-upper part of the socket, while pincer lesions produce more widespread wear around the rim. MRI can also reveal chondrolabral separation, where the labrum pulls away from the cartilage at their junction, a finding that helps surgeons plan their approach.
Tendons and Muscles Around the Hip
MRI clearly distinguishes between tendon inflammation, partial tears, and complete tears in the muscles surrounding the hip. The gluteal tendons, which attach to the bony prominence on the outer hip, are among the most commonly affected. Tendinosis (chronic degeneration without a discrete tear) appears as a swollen tendon with abnormal signal. A partial-thickness tear shows a thickened tendon with brighter signal on certain sequences, while a complete tear shows a visible gap in the tendon, sometimes with measurable retraction of the torn end.
This matters because lateral hip pain, often loosely called “hip bursitis,” is more commonly caused by gluteal tendon problems than by actual bursal inflammation. MRI can sort out whether the pain stems from the tendons, the bursa, or the thick band of tissue running along the outer thigh. Getting the right diagnosis changes the treatment plan considerably, since tendon tears may need surgical repair while bursitis typically responds to conservative measures.
Inflammatory and Systemic Conditions
MRI can detect active inflammation inside bone and joints before any structural damage is visible on X-ray. This is particularly valuable for conditions like inflammatory arthritis affecting the sacroiliac joints, which sit just behind the hip. Bone marrow swelling, erosions, and fatty changes within the bone all show up on MRI, sometimes years before X-ray changes appear. For younger patients with inflammatory back and hip pain, MRI may be used as a first-line imaging tool rather than waiting for X-ray findings to develop.
Standard MRI vs. MR Arthrogram
A standard hip MRI requires no injection. You lie in the scanner for roughly 30 to 45 minutes while multiple image sequences are captured. An MR arthrogram adds a step: before the scan, a radiologist uses fluoroscopy (live X-ray) to guide a needle into the hip joint and injects a small amount of diluted contrast fluid, typically about 15 cc. The contrast fills the joint space, outlining structures like the labrum and cartilage surfaces with much greater clarity.
The arthrogram version is generally ordered when your doctor suspects a labral tear or cartilage damage and needs the highest level of detail. For problems like stress fractures, AVN, tendon tears, or bursitis, a standard MRI without contrast is sufficient.
What to Expect During the Scan
You can eat normally and take your regular medications before a hip MRI unless specifically told otherwise. You’ll change into a gown and remove anything metal: jewelry, watches, hairpins, eyeglasses, hearing aids. Clothing with snaps or zippers can’t be worn in the scanner. If you have metal implants, let your imaging center know ahead of time so they can confirm compatibility.
The scanner itself is a large tube, and you’ll lie on a table that slides into it. The machine is loud, producing rhythmic knocking and buzzing sounds, so you’ll typically be given earplugs or headphones. Staying still is important for image quality. The scan usually takes 30 to 45 minutes for a standard study, potentially a bit longer if an arthrogram injection is performed first. Results are typically read by a radiologist and sent to your ordering physician within a few days.