A hip MRI report is a dense collection of medical shorthand, and most people walk away from their doctor’s office still unsure what half of it means. The good news is that the language follows patterns you can learn to decode. Reports describe what each tissue looks like on different types of images, assign grades or measurements where formal systems exist, and flag anything that deviates from normal. The trickier part is that many findings on hip MRI show up in people with zero pain, so understanding what a report says is only the first step. Knowing which findings actually matter for your symptoms requires context that the report itself rarely provides.
What the Image Types Mean
Your report will reference specific MRI sequences, and each one highlights different tissues. T1-weighted images make fat appear bright and water appear dark, which gives excellent contrast for bone marrow and helps spot things like fractures or areas where normal marrow has been replaced by something abnormal. T2-weighted images flip the contrast so that water-rich tissue lights up. Fluid, swelling, and inflammation all glow white on T2 sequences, making them the go-to for detecting edema, joint effusions, and cysts. STIR (short tau inversion recovery) sequences are a variation that suppresses the fat signal and makes fluid stand out even more sharply, so they are especially useful for catching bone marrow edema or subtle stress injuries. If your report mentions “increased signal on STIR” or “hyperintense on T2,” it is telling you fluid or swelling is present in that spot.
MRI is the preferred tool for investigating hip pain precisely because it can image soft tissue, bone, and cartilage in multiple planes without radiation.1PubMed Central. Magnetic resonance imaging of the hip: anatomy and pathology The three standard planes are axial (cross-sections as if slicing you horizontally), coronal (front-to-back slices), and sagittal (side-to-side slices). Some protocols add oblique-axial or radial sequences angled along the femoral neck, which give a better look at the labrum and the shape of the femoral head. If your report mentions “radial images” or “oblique axial,” the radiologist was looking specifically at the labrum or the head-neck junction.
Labral Tears and What the Grading Means
The acetabular labrum is a ring of fibrocartilage lining the rim of your hip socket. It deepens the socket and helps seal in joint fluid. Labral tears are one of the most commonly reported findings, and your report may describe a tear using a classification system. The two best-known systems are the Czerny classification (an imaging-based grading) and the Lage classification (originally arthroscopic). Czerny grades range from normal to grade 3 (a torn labrum with contrast or fluid extending into the substance of the labrum or detaching it from the acetabular rim).2PubMed. Hip Capsulolabral Complex: Anatomy, Disease, MRI Features, and Postoperative Appearance Your report may also describe the location using a clock-face system, where the front of the socket is roughly 12 o’clock and locations are noted clockwise from there. MRI localization using this system matches what the surgeon finds during arthroscopy within about one clock position in most cases.3PubMed. Classification and localization of acetabular labral tears
If your report says something like “anterior-superior labral tear at approximately 1 o’clock,” it is pointing to a tear in the front-upper part of the socket rim, which is the most common location. Terms like “labral degeneration” or “intrasubstance signal” describe wear or fraying within the labrum that may not be a full tear. A “paralabral cyst” is a small fluid-filled pocket adjacent to the labrum, often a sign that a tear has been present long enough for fluid to track through it.
For detecting labral tears, direct MR arthrography, where contrast is injected into the joint before scanning, outperforms standard MRI.4PubMed. MRI of Labral and Chondral Lesions of the Hip The injected fluid distends the joint and outlines the labrum so that small tears become visible. Accuracy for labral lesion detection with direct arthrography reaches roughly 92 percent.5PubMed. Diagnostic performance of direct traction MR arthrography of the hip: detection of chondral and labral lesions with arthroscopic comparison If you had a standard, non-arthrographic MRI and the labrum looked fine, a true small tear hasn’t been definitively ruled out, though standard 3-T MRI still catches the majority of labral tears with sensitivity around 88 to 90 percent.6PubMed Central. Comparison of 3.0-T MR vs 3.0-T MR arthrography of the hip for detection of acetabular labral tears and chondral defects in the same patient population
Femoroacetabular Impingement on Your Report
Femoroacetabular impingement (FAI) is a structural mismatch between the ball and socket that causes abnormal contact during movement. Reports typically distinguish two patterns. Cam impingement involves a bump or loss of the normal spherical contour at the femoral head-neck junction. Pincer impingement involves over-coverage of the femoral head by the acetabulum. Many people have elements of both.
The key measurement you’ll see for cam morphology is the alpha angle, measured on a cross-sectional image through the femoral neck. An alpha angle above roughly 55 degrees suggests an abnormally prominent head-neck junction.7PubMed. Femoroacetabular impingement: can the alpha angle be estimated? Your report may also mention the lateral center-edge angle, which measures how much the acetabular roof covers the femoral head on coronal images. A high lateral center-edge angle points toward pincer-type over-coverage.8PubMed Central. Magnetic Resonance Imaging-Based Comparative Assessment of Cam and Pincer Hip Morphology between Soccer Players and Non-athlete Controls If either angle is flagged as abnormal, the radiologist is identifying a bony shape that could contribute to impingement, though the shape alone does not confirm that impingement is causing your symptoms.
One thing worth knowing is that even trained readers struggle to eyeball whether an alpha angle is normal or abnormal. One study found that visual assessment alone was a poor predictor when compared to actual measurements, with even normal angles being judged as possibly abnormal about half the time.7PubMed. Femoroacetabular impingement: can the alpha angle be estimated? This is why the report should include the actual number rather than just a subjective impression.
Cartilage Loss and Osteoarthritis Findings
If your report describes cartilage thinning, cartilage defects, or chondral lesions, the radiologist is documenting damage to the smooth, slippery layer covering the joint surfaces. Reports often grade cartilage loss as partial thickness (some cartilage remains) or full thickness (bone is exposed). Formal scoring systems divide the joint into subregions. The femoral head alone gets split into roughly six zones, and the acetabulum into four, so a thorough report might list the specific subregion and the severity of cartilage loss in each.9PubMed Central. Scoring Hip Osteoarthritis with MRI (SHOMRI): a Whole Joint Osteoarthritis Evaluation System
Beyond cartilage, MRI picks up other features of osteoarthritis that X-rays miss. Bone marrow edema-like lesions (sometimes called bone marrow lesions, or BMLs) appear as bright areas within the bone on fluid-sensitive sequences and indicate stress or inflammation in the subchondral bone. Subchondral cysts show up as well-defined, fluid-bright pockets in the bone just beneath the cartilage surface. Osteophytes (bone spurs) and joint effusions may also be described. A semiquantitative scoring system called HOAMS showed strong correlation between the severity of these MRI-detected features and the radiographic grade of osteoarthritis.10PubMed. Hip Osteoarthritis MRI Scoring System (HOAMS): reliability and associations with radiographic and clinical findings
Of all these features, bone marrow lesions have the most reliable link to actual hip pain. A systematic review found moderate evidence that the presence of BMLs, and changes in BMLs over time, correlated with pain severity and progression. The evidence linking other MRI features like cartilage defects or osteophytes to pain was limited or conflicting.11PubMed Central. The relationship between MRI-detected hip abnormalities and hip pain in hip osteoarthritis: a systematic review That said, acetabular cartilage lesions (as opposed to femoral-side lesions) have been associated with worse patient-reported hip function scores, so the location of cartilage damage matters.12PubMed Central. Association of cartilage defects, and other MRI findings with pain and function in individuals with mild-moderate radiographic hip osteoarthritis and controls
Avascular Necrosis and the Double Line Sign
Avascular necrosis (AVN), also called osteonecrosis, happens when the blood supply to part of the femoral head is disrupted and bone tissue dies. MRI is extremely sensitive for catching this early, often before any changes appear on X-ray. On T1-weighted images, AVN typically shows as a band of low signal in the femoral head, marking the boundary between healthy and ischemic bone. On T2-weighted images, a hallmark finding called the “double line sign” may appear: a low-signal outer band with a bright inner rim. This pattern is considered virtually diagnostic of AVN.13PubMed. Avascular osteonecrosis of the hip: The vision of the radiologist (radiology, MRI, CT and scintigraphy) The bright inner line represents the reactive tissue interface between living and dead bone, and the low-signal outer line corresponds to sclerotic repair tissue.14PubMed. Chemical shift and the double-line sign in MRI of early femoral avascular necrosis
Reports will usually describe the size and location of the necrotic segment and whether there is any collapse of the femoral head surface. Early-stage AVN with intact head contour is treated very differently from late-stage disease with collapse, so these details carry significant weight for treatment decisions.
Stress Fractures and Bone Marrow Edema
Femoral neck stress fractures are a common reason for hip MRI in active people. On STIR or T2-weighted images, a stress reaction shows up as a diffuse area of bright signal in the bone (edema), and a true stress fracture adds a dark line within that edema representing the fracture itself. The distinction matters. In a study of patients with femoral neck stress injuries, all patients who had isolated bone marrow edema without a visible fracture line on MRI recovered with conservative treatment and did not progress to a full fracture.15Journal of Bone and Joint Surgery. Femoral Neck Stress Fractures: MRI Risk Factors for Progression This means the presence or absence of a fracture line in your report is a major factor in how urgently the injury is managed.
If your report describes bone marrow edema at the femoral neck, it may also note how extensive it is. Follow-up MRI shows that edema from stress fractures resolved within three months in most patients, though in some cases it persisted for up to a year.16PubMed. Resolution of abnormal MR signal intensity in patients with stress fractures of the femoral neck So if a follow-up scan still shows some residual signal, that alone doesn’t mean the fracture hasn’t healed.
Greater Trochanteric Pain and Gluteal Tendon Findings
Pain along the outside of the hip, once lumped under “trochanteric bursitis,” is more often related to the gluteal tendons than to the bursa itself. Greater trochanteric pain syndrome is commonly due to gluteus medius or gluteus minimus tendon injury rather than true bursitis.17PubMed. MRI and US of gluteal tendinopathy in greater trochanteric pain syndrome Your report may describe tendinosis (degeneration within the tendon), partial tears, or complete tears of these tendons, along with indirect signs like fluid in the trochanteric bursa or fatty atrophy of the muscle.
Here is where interpretation gets tricky: about half of people without any lateral hip pain also have gluteal tendon abnormalities on MRI. In one study, 88 percent of hips with trochanteric symptoms showed gluteal tendinopathy, but so did 50 percent of hips without symptoms. The only statistically significant difference between painful and pain-free hips was the presence of tendinopathy itself; other findings like bursal fluid, edema around the tendons, and partial-thickness tears did not reliably distinguish the two groups.18PubMed. Correlation of MRI findings with clinical findings of trochanteric pain syndrome So seeing “gluteus medius tendinopathy” on your report does not automatically explain your pain, especially if your symptoms are in a different location.
Ischiofemoral Impingement
This less-common diagnosis involves the space between the ischial tuberosity (the “sit bone”) and the lesser trochanter of the femur becoming too narrow, pinching the quadratus femoris muscle that runs between them. On MRI, the radiologist measures the ischiofemoral space. In symptomatic patients, this space averages about 13 mm compared to roughly 23 mm in controls.19PubMed. Ischiofemoral impingement syndrome: an entity with hip pain and abnormalities of the quadratus femoris muscle Signs of impingement include edema within the quadratus femoris muscle, partial tearing, and in chronic cases, fatty infiltration replacing normal muscle tissue.20PubMed Central. Ischiofemoral impingement syndrome, an unusual entity of hip pain: A case report and literature review If your report mentions quadratus femoris edema and a narrow ischiofemoral space, this diagnosis may be in play.
Deep Gluteal Syndrome and Sciatic Nerve Entrapment
Hip MRI sometimes catches conditions that present as buttock or posterior thigh pain rather than classic hip joint pain. Deep gluteal syndrome refers to sciatic nerve entrapment in the gluteal region by structures other than a herniated disc. The piriformis muscle is the most commonly blamed structure, but MRI can also reveal entrapment by fibrous bands, the hamstring tendons, or even vascular anomalies.21PubMed Central. Deep gluteal syndrome Reports may describe asymmetric enlargement or edema of the piriformis muscle, or direct contact between a structure and the sciatic nerve. If your pain radiates down the back of your leg and your report describes piriformis abnormalities or sciatic nerve signal changes, this is the finding your doctor is likely focusing on.
Why Many Findings Do Not Matter
This is arguably the most important thing to understand about your hip MRI report. A landmark study that scanned the hips of people with no pain at all found labral tears in 69 percent, cartilage defects in about a quarter, and bony bumps consistent with cam morphology in a fifth.22PubMed. Prevalence of abnormal hip findings in asymptomatic participants: a prospective, blinded study A separate study of people being treated for one painful hip found that the opposite, completely pain-free hip also had labral tears in over 40 percent of cases and cartilage lesions in 15 to 17 percent.23PubMed Central. Acetabular Labral Tears Are Common in Asymptomatic Contralateral Hips With Femoroacetabular Impingement These numbers mean that seeing “labral tear” or “chondral defect” on your report does not automatically explain your pain. The finding has to match your clinical picture: where the pain is, what movements trigger it, and what the physical examination shows.
This is why radiology reports almost always end with a line about “clinical correlation.” The radiologist is describing what they see; your treating clinician is the one who decides which findings are clinically relevant. A labral tear at 1 o’clock in someone with anterior groin pain and a positive impingement test on examination is probably meaningful. That same tear in someone whose primary complaint is lateral hip pain with tenderness over the greater trochanter may be incidental.
Metal Implants and Image Artifacts
If you have metal hardware in or near your hip, such as screws, plates, or a joint replacement, the MRI report may mention artifact. Metal distorts the magnetic field and creates signal voids, bright halos, or geometric warping that can obscure nearby tissues. The severity depends on the type of metal: titanium alloys produce much less artifact than stainless steel or cobalt-chromium alloys.24PubMed Central. Visual and quantitative assessment of hip implant-related metal artifacts at low field MRI: a phantom study comparing a 0.55-T system with 1.5-T and 3-T systems Higher field-strength magnets (3 Tesla versus 1.5 Tesla) tend to produce more artifact around metal implants, with worse fat suppression and larger signal distortion, although specialized artifact-reduction sequences can substantially improve image quality at either strength.25PubMed. Metal artifact suppression at the hip: diagnostic performance at 3.0 T versus 1.5 Tesla
If your report states that certain structures could not be assessed due to artifact, it is not a failure of the scan. It is an honest limitation. Your doctor may recommend a different imaging modality, or request the scan at a lower field strength or with metal-reduction sequences for better visualization.
MR Arthrography and What to Expect
Some hip MRIs are performed after injecting contrast directly into the joint under fluoroscopic guidance. This is called direct MR arthrography, and it is the gold standard for evaluating the labrum and articular cartilage. The injected fluid distends the joint capsule, separating structures that normally sit flush against each other and making small tears and cartilage flaps visible that a standard MRI might miss.
The injection itself causes temporary discomfort. In a prospective evaluation of over a thousand patients, the hip was the joint where arthrography caused the most pronounced pain increase, peaking about four hours after the injection. No serious complications like infection occurred, and side effects were limited to minor issues like transient pressure, muscle aches, and headache.26PubMed. Pain and other side effects after MR arthrography: prospective evaluation in 1085 patients If your report was from an arthrogram, you’ll see mentions of contrast filling various recesses of the joint. “Contrast extending into” a labral tear or “undermining” the labral base is confirmation that the tear communicates with the joint space.
Post-Surgical Reports
Reading an MRI report after hip surgery is even more complex. If you’ve had a labral repair, the report may describe whether anchors are intact, whether the labrum is re-attached to the rim, or whether a re-tear has occurred. After arthroscopic surgery, MRI can also show adhesions (scar tissue bands within the joint) and capsular disruption (thinning or gap in the joint capsule from the surgical approach). These findings have variable appearances on MRI, and distinguishing a normal post-surgical appearance from a new problem often requires comparison with earlier imaging or specific knowledge of what procedure was performed.27International Society for Magnetic Resonance in Medicine. MRI of the Post-Operative Hip Following Arthroscopic Repair: What are the Imaging Characteristics of Labrum Re-Tear and Capsular Complications?
Pediatric Hip Conditions on MRI
In children and adolescents, hip MRI reports may describe conditions that adults never see. Legg-Calvé-Perthes disease involves loss of blood supply to the growing femoral head, and early MRI findings include low T1 signal in the epiphysis with varying degrees of bone marrow edema. A subchondral bright line on T2 images, sometimes called the crescent sign, indicates a subchondral fracture and worsening disease. In later stages, the report may describe fragmentation, deformation, or collapse of the femoral head with abnormal thickening of the overlying cartilage.28Indian Journal of Musculoskeletal Radiology. A comprehensive review of the common developmental disorders of hip – Developmental dysplasia of the hip, slipped capital femoral epiphysis, and Perthes disease Developmental dysplasia and slipped capital femoral epiphysis are other conditions where MRI plays a diagnostic role, though those are typically identified by the clinical team before the scan is ordered.
When Radiologists Disagree
It is worth acknowledging that MRI interpretation is not perfectly objective. For hip osteoarthritis grading, agreement between different readers using standard classification scales is only moderate.29PubMed Central. Reliability of radiographic knee and hip osteoarthritis classification between radiologists and orthopaedic surgeons Some features, like bone marrow lesions, show strong agreement between readers, while others, like small cysts, are much less consistently identified.10PubMed. Hip Osteoarthritis MRI Scoring System (HOAMS): reliability and associations with radiographic and clinical findings If you get a second opinion on the same images and the two reports differ on a borderline finding, this is a normal feature of medical imaging, not necessarily a sign that one radiologist made a mistake. The more clear-cut the abnormality, the more likely two readers will agree. It’s the subtle, borderline findings where disagreement creeps in, which is also where clinical context becomes most important for deciding what to do next.