MRI Hip – Generic Standard Protocol

MRIninja Knowledge Base | Master / General Page Version 1.0 — April 2026 | Evidence review through April 2026 Audience: Radiologists · MSK Radiologists · MRI Technologists · Advanced Students

1. Executive Summary

Hip MRI occupies a unique and technically demanding position among peripheral joint protocols. The hip is a deep, ball-and-socket joint embedded within the largest muscle groups in the body, oriented obliquely in three planes, and surrounded by complex periarticular soft tissue structures. It is also one of the only joints in the body where both wide-field-of-view bilateral assessment (for bone marrow screening, symmetric comparison, avascular necrosis) and narrow-field-of-view unilateral high-resolution imaging (for labral tears, cartilage, impingement) are clinically required — often on the same patient, and sometimes on the same examination.

This dual-scale requirement distinguishes hip MRI from knee MRI fundamentally and defines the protocol architecture: every standard hip examination requires at least one wide-FOV pelvis-level acquisition (coronal T1 and/or coronal fluid-sensitive sequence) combined with dedicated small-FOV high-resolution imaging of the target hip. Without the wide-FOV component, bilateral avascular necrosis, bilateral marrow disease, and contralateral hip pathology are invisible. Without the small-FOV component, labral tears, cartilage delamination, and early impingement morphology at the femoral head-neck junction are below reliable detection.

Compared with CT, hip MRI provides decisive superiority for soft tissue characterisation (labrum, cartilage, tendons, bursa), bone marrow assessment, and absence of ionising radiation. CT retains advantages for precise cortical bone detail (cam deformity morphometry, Pincer impingement measurement, surgical implant planning, complex fracture mapping) and for patients with MRI contraindications. MR arthrography (intraarticular gadolinium) substantially increases sensitivity for labral tears and cartilage fissures over non-contrast MRI and is the gold standard for these indications when clinical certainty is required.

Ultrasound assesses periarticular tendon pathology (gluteus medius/minimus tendons, iliopsoas) and guides injections effectively but cannot assess labrum, cartilage, bone marrow, or deep ligamentous structures. It is complementary, not equivalent, to MRI.

1.1 Core Strengths

• Bone marrow assessment: The hip is the most frequent site of avascular necrosis (AVN/osteonecrosis). MRI is the most sensitive and specific modality for AVN at all stages, detecting marrow oedema and the characteristic double-line sign before radiographic changes appear.
• Labral assessment: Direct visualisation of the acetabular labrum in multiple planes. Non-contrast MRI at 3T approaches MR arthrography sensitivity for moderate-to-large labral tears; MR arthrography remains superior for small and partial-thickness tears.
• Cartilage: Direct visualisation of acetabular and femoral head articular cartilage. 3T with dedicated sequences approaches the sensitivity of CT arthrography for cartilage assessment.
• Bilateral assessment in one examination: The wide-field coronal acquisition simultaneously evaluates both femoral heads, both acetabula, and the pelvic bone marrow — enabling comparison and symmetric disease detection.
• Tendon and bursa: Gluteus medius/minimus tendons, iliopsoas tendon, greater trochanteric bursal complex, and ischiofemoral space all directly assessed.
• No ionising radiation: Critical for the often-young patient population (FAI, labral tears, athletes) and for repeat examinations.

1.2 Intrinsic Limitations of the Generic Protocol

Labral sensitivity gap: Non-contrast hip MRI — even at 3T — has lower sensitivity for small and partial-thickness labral tears compared to MR arthrography (direct intraarticular gadolinium). ACR Appropriateness Criteria [2] specify MR arthrography as "usually appropriate" when a labral tear is specifically suspected. The generic non-contrast standard protocol is a compromise that may miss small or partial-thickness labral pathology.

Cartilage sensitivity limitations: The acetabular cartilage (at 2–4 mm thickness) and the femoral head cartilage (at 1–3 mm thickness) are among the thinnest in the body. Standard 3–4 mm slice thickness MRI produces significant partial volume averaging of thin cartilage; dedicated high-resolution or 3D sequences are required for reliable cartilage assessment.

Oblique joint orientation: The hip is oriented obliquely in the body — the femoral neck makes a ~125–135° angle with the femoral shaft in the coronal plane and approximately 10–20° of anteversion in the axial plane. Standard orthogonal planes (coronal, axial, sagittal) are therefore not "true" planes relative to the hip joint, and oblique sequences (axial oblique parallel to femoral neck) are needed for joint-specific anatomy.

Motion artefact from bowel: The hip is surrounded by the lower abdomen and pelvis. Bowel peristalsis generates phase-encoding ghosting that propagates through the hip joint in large-FOV sequences. Saturation bands over the anterior abdomen are mandatory for pelvic-level acquisitions.

Bilateral examination time: A complete standard bilateral hip examination (wide-FOV pelvis sequences + bilateral small-FOV dedicated sequences) requires 35–45 minutes — longer than most other peripheral joint protocols.

Post-arthroplasty limitations: Total hip arthroplasty (THA) hardware generates extensive susceptibility artefact that renders standard MRI diagnostically limited. Dedicated MARS protocols are required and constitute a child page.

When a dedicated child protocol is required: MR arthrography for labral tears/cartilage assessment, post-arthroplasty assessment (MARS protocol), suspected infection, suspected primary bone tumour, paediatric hip (developmental dysplasia, Perthes disease, SCFE), post-operative labral repair, and dedicated AVN staging.

2. Main Clinical Indications

2.1 Standard Indications

Avascular necrosis (osteonecrosis) of the femoral head is the most critical indication for hip MRI. MRI has sensitivity and specificity exceeding 95% for AVN at all stages, detecting the double-line sign and marrow oedema pattern before radiographic changes appear [1, 3]. ACR Appropriateness Criteria for Osteonecrosis designate MRI without contrast as "usually appropriate" and the most sensitive initial imaging modality [3]. The standard non-contrast protocol with T1 and fluid-sensitive sequences is sufficient for AVN detection and staging. Bilateral examination is mandatory (contralateral AVN rate: 50–80%).

Chronic hip pain — suspected femoroacetabular impingement (FAI): FAI (cam and/or pincer types) is the most common cause of hip pain in young and middle-aged active patients. ACR Appropriateness Criteria [2] designate MRI without contrast as "usually appropriate" for initial evaluation of suspected FAI/impingement when radiographs are negative or non-diagnostic. MRI identifies osseous cam/pincer morphology, labral tears, chondrolabral junction injury, and associated pathology. The non-contrast standard protocol is a reasonable first step; MR arthrography provides superior labral and cartilage detail when surgical planning is intended.

Chronic hip pain — suspected labral tear: ACR Appropriateness Criteria [2] designate MR arthrography as "usually appropriate" for suspected labral tear. Non-contrast MRI (particularly at 3T) is rated "may be appropriate" with lower diagnostic confidence for small and partial labral tears. The generic non-contrast standard protocol is appropriate when MR arthrography is not available or when the clinical question is broader than isolated labral pathology.

Acute hip pain — occult fracture: When radiographs are negative or non-diagnostic in the setting of acute hip pain (particularly in elderly osteoporotic patients or after falls), MRI is the preferred modality for occult femoral neck and intertrochanteric fractures. ACR Appropriateness Criteria 2024 [1] support MRI as the next investigation after negative radiographs for suspected hip fracture. The standard protocol T1 sequence shows fracture lines as dark bands interrupting bright marrow fat.

Greater trochanteric pain syndrome (GTPS): The standard protocol with coronal fluid-sensitive and axial sequences adequately assesses gluteus medius and minimus tendon integrity, greater trochanteric bursal pathology, and iliotibial band anatomy. Ultrasound is complementary; MRI is preferred when tendon tear extent assessment is required for surgical planning.

Bone marrow surveillance in systemic disease: In patients with haematological malignancies, metastatic disease, steroid therapy (AVN risk), sickle cell disease, or Gaucher's disease, the bilateral wide-FOV hip examination provides marrow status assessment across both femoral heads and the pelvic marrow in a single acquisition.

Hip pain with suspected inflammatory or infectious pathology: Standard non-contrast protocol as initial assessment; post-contrast sequences are added when synovitis, abscess, or osteomyelitis is suspected.

Hip pain in younger patients — developmental dysplasia, Legg-Calvé-Perthes disease, SCFE: MRI provides cartilage, bone marrow, and vascular supply assessment not possible with other modalities. Dedicated paediatric protocols are child pages.

2.2 Urgent Red Flags Requiring Expedited or Emergency Imaging

3. Preparation Reference

3.1 Anatomy-Specific Preparation Items

Total hip arthroplasty and surgical hardware: THA components (metallic cup, femoral stem, acetabular screws, cables) generate extensive susceptibility artefact that makes standard hip MRI diagnostically inadequate for the implanted joint. Patients with THA require a dedicated MARS protocol with SEMAC/WARP/MAVRIC-SL sequences (child page). For unilateral THA, the contralateral native hip can be assessed with the standard protocol; the arthroplasty side requires MARS sequences.

Partial hip arthroplasty (hemiarthroplasty, surface replacement), prior osteotomy hardware (screws, plates), and core decompression tracts (residual hardware) all produce less severe but still clinically important artefact. The standard protocol should be attempted; metal artefact extent must be documented.

Prior hip surgery: Hip arthroscopy (suture anchors, labral repair tacks), hip core decompression (drill tract), PAO/rotational osteotomy (plates, screws), and ORIF of femoral neck fractures all modify the expected imaging appearance and may limit artefact-free assessment of adjacent structures.

Clothing and preparation: All metallic items at the pelvis and hip level must be removed: belt buckles, trouser rivets, zippers. A gown is recommended. Patients should be reminded that the imaging region includes the pelvis; intimate undergarments with metallic components (underwired, metallic fasteners) must be replaced.

Bowel preparation: Not routinely required, but patients should ideally void before the examination. Bowel gas and peristalsis are the primary artefact sources in large-FOV hip sequences. If a patient has severe bowel distension or diarrhoea, consider rescheduling unless urgent. Antiperistaltic agents (hyoscine butylbromide) may be considered in departments where bowel motion artefact is a recurrent quality problem, but are not routinely used.

Patient history modifying the protocol:

• Known or suspected AVN → bilateral examination mandatory
• Suspected labral tear (surgical planning) → consider MR arthrography (child page)
• THA present → MARS protocol mandatory for arthroplasty side
• Known malignancy → DWI + contrast; extend to whole pelvis
• Suspected infection → contrast required
• Pregnancy → non-contrast; MRI generally deferred to second trimester unless urgent

3.2 Patient Positioning on the MRI System

Patient position: Supine, feet-first entry. Both lower limbs in neutral position or very slight internal rotation. The natural tendency of the lower limbs in the supine position is external rotation; this must be gently corrected to bring the femoral necks into a more frontal orientation, improving axial oblique and radial slice planning.

Coil selection: For hip MRI, coil selection is directly determined by the clinical indication:

• Bilateral wide-FOV examination (standard for bilateral comparison, AVN, marrow disease): Body matrix coil (anterior body matrix + posterior spine coil table) covering both hips simultaneously. This configuration provides adequate SNR for large-FOV acquisitions.
• Unilateral dedicated high-resolution examination (labral tear, FAI, cartilage): Dedicated surface coil or flexible surface coil over the target hip provides substantially higher SNR for small-FOV labral and cartilage assessment. The ESSR standard hip protocol specifies a body coil for bilateral and a surface coil for unilateral examination [4].

In standard clinical practice, a pragmatic approach is often used: the wide-FOV bilateral sequences are acquired with the body coil configuration; then the coil is changed to a surface coil for the dedicated small-FOV sequences of the symptomatic hip. Some departments complete the entire examination with the body coil if a surface coil is not available, accepting reduced SNR for the small-FOV component.

Centering: For bilateral hip examination: the isocentre should be at the pubic symphysis level — centred between both femoral heads. For unilateral dedicated examination: centre at the femoral head of the symptomatic side.

Internal rotation: Mild internal rotation of both lower limbs (10–15°, toes together) reduces the anteversion angle of the femoral necks relative to the coronal plane, improving the appearance of the femoral heads on coronal sequences and facilitating axial oblique planning parallel to the femoral neck. Foam pads or tape across the feet maintains this position.

Immobilisation: Sandbags or foam wedges alongside each lower limb prevent external rotation drift during the examination. Patients should be instructed to remain still and avoid any hip movement.

Pre-scan technologist checks:

1. Verify coil configuration (body coil vs. surface coil) and activate correct elements on console.
2. Confirm internal rotation maintained before starting.
3. Confirm no metallic items at pelvis/hip level.
4. Centre isocentre at pubic symphysis (bilateral) or femoral head (unilateral).
5. Acquire three-plane localiser and verify both femoral heads (bilateral) or the target hip (unilateral) within the FOV.
6. Visually confirm internal rotation on the axial localiser before proceeding.

4. Standard Protocol Design

The standard hip protocol is structured in two tiers:

Tier 1 — Wide-field bilateral pelvis level: Coronal T1 and coronal fluid-sensitive (STIR/PD-FS or T2-FS) of both hips. Essential for bilateral comparison, AVN, bone marrow screening, and symmetric disease. Large FOV (350–450 mm), moderate resolution. For sequence-level protocol optimisation, vendor terminology and artefact management, see the dedicated MRIninja page STIR Sequence.

Tier 2 — Small-field unilateral hip: Dedicated sequences of the symptomatic hip with small FOV (160–200 mm), high resolution, covering the labrum, cartilage, tendons, and periarticular structures. These include the axial oblique (parallel to femoral neck) and coronal and/or sagittal sequences dedicated to the single joint.

4.1 Mandatory Core Sequences

4.2 Conditional Sequences

4.3 Rationale Summary Per Sequence

Wide-FOV Coronal T1 — the bilateral bone marrow baseline. Identical role to the spinal T1: bright fatty marrow is the baseline against which T1-dark marrow replacement (AVN, infiltration, oedema, fracture) is identified. The wide FOV (350–450 mm) covers both femoral heads, both acetabula, both iliac wings, and both proximal femoral shafts — the entire bone marrow territory of the pelvis relevant to hip disease. The AVN double-line sign, osteonecrotic band, and marrow replacement are all detected on the wide-FOV coronal T1. This sequence cannot be replaced by the small-FOV unilateral coronal T1 because contralateral hip disease would be missed.

What it detects well: AVN (focal T1 dark segment in femoral head), fracture lines (dark bands interrupting bright marrow), marrow infiltration (diffuse T1 dark replacement), cortical bone integrity of femoral neck, bilateral comparison.

Technologist note: The wide-FOV T1 is NOT fat-suppressed. Bright marrow fat is the diagnostic signal. Any fat suppression applied to this sequence destroys its primary diagnostic purpose.

Wide-FOV Coronal STIR or PD-FS — the bilateral bone marrow oedema screen. Identical role to spinal STIR: fat suppression + T1+T2 additive contrast reveals marrow oedema at both femoral heads and across the pelvis. STIR at the wide FOV of the pelvis has better B0-independent fat suppression than spectral fat saturation (CHESS/SPIR) and is preferred for this large-FOV bilateral sequence. STIR TI must be calibrated for field strength (≈160 ms at 1.5T; ≈200 ms at 3T).

Critical STIR limitation: STIR must never be acquired after gadolinium — same principle as in all spinal protocols.

Small-FOV Coronal PD-FS — the primary labral and cartilage sequence of the target hip. At small FOV (160–200 mm) with high-resolution matrix (256×256 to 320×320), the acetabular labrum, acetabular cartilage, femoral head cartilage, ligamentum teres, transverse ligament, and fovea capitis are directly imaged. The superoposterior labrum (the most common labral tear site) is best seen on coronal images.

What it detects well: Superior and posterosuperior labral tears (optimal plane), acetabular cartilage loss, femoral head cartilage loss, ligamentum teres tears, joint effusion, paralabral cysts.

Axial oblique PD-FS — the anterosuperior labrum and cam impingement sequence. This sequence is planned parallel to the femoral neck axis — it is not the standard axial plane of the patient but an oblique that cuts perpendicular to the femoral head, providing a cross-section of the femoral head-neck junction in its true anatomical orientation. This is the most important plane for detecting anterosuperior labral tears (92% of labral tears occur at the anterosuperior and anterior labrum) and cam morphology (the osseous bump at the femoral head-neck junction in cam-type FAI).

What it detects well: Anterosuperior and anterior labral tears, cam deformity (alpha angle measurement), anterior cartilage delamination, iliopectineal bursitis (extension of joint fluid anteriorly), iliopsoas tendon.

Technologist note: Correct angulation of the axial oblique parallel to the femoral neck is the most technically demanding positioning step in hip MRI. The angulation must be planned from the coronal localiser, confirmed in the sagittal plane, and verified by the presence of a circular femoral head cross-section on the final images.

Sagittal PD-FS — the anterior and posterior labral planes. The sagittal plane provides lateral cross-sections through the hip joint, showing the anterior and posterior labrum simultaneously, the iliopsoas tendon, and the anterior and posterior periarticular structures.

What it detects well: Anterior labral tears (often best shown on sagittal), posterior labral tears, iliopsoas tendon, pectineus, femoral head anterior and posterior cartilage.

4.4 Sequence Matching and Cross-Sequence Consistency

The wide-FOV bilateral sequences (coronal T1, coronal STIR/PD-FS) must share identical geometry for direct bilateral comparison: same slice thickness, gap, FOV, and number of slices. These sequences define the bilateral baseline; any asymmetry in signal or morphology is only meaningful if the geometry is matched.

The small-FOV sequences of the target hip (coronal PD-FS, axial oblique PD-FS, sagittal PD-FS) do not need to share geometry with the bilateral sequences but must collectively cover the entire joint. Any labral finding identified on one plane must be confirmable on at least one orthogonal plane — isolated single-plane findings should be interpreted with caution.

For contrast examinations: pre-contrast T1 fat-suppressed must precisely match post-contrast in geometry. For AVN follow-up and serial monitoring: identical coil, FOV, and positioning are essential for valid comparison of osteonecrotic segment size and marrow signal evolution.

4.5 Fat Suppression in Hip MRI

Fat suppression in hip MRI serves three distinct clinical roles that drive technique selection:

1. Bilateral wide-FOV STIR (bone marrow oedema): Large FOV (350–450 mm) at pelvis level is the most challenging fat suppression context in MSK MRI. The B0 inhomogeneity across the pelvis (multiple tissue interfaces, large body diameter) makes spectral fat saturation (CHESS/SPIR) unreliable at the edges of the FOV and at the fat-containing pelvic soft tissue boundaries. STIR is strongly preferred for the bilateral coronal sequence because of its B0-independent fat suppression. Evidence from Del Grande et al. confirms STIR provides more homogeneous fat suppression than SPAIR over large pelvic FOV [5]. The trade-off is lower SNR than spectral methods. STIR cannot be used post-gadolinium.

2. Small-FOV dedicated hip sequences (labral, cartilage, tendon): The small FOV (160–200 mm) centred on a single femoral head produces much better B0 homogeneity than the bilateral wide-FOV sequence. Spectral fat saturation (SPAIR at 3T, SPIR at 1.5T) provides higher SNR and adequate suppression homogeneity at small FOV. SPAIR is preferred over CHESS at 3T for B0 robustness within the joint. Dixon technique is the most robust alternative and is increasingly preferred at 3T centres.

3. Post-contrast T1 fat-suppressed (enhancement characterisation): SPAIR or Dixon are the preferred techniques. STIR is contraindicated post-gadolinium (same principle as in all spinal protocols).

Fat suppression is not applied to: wide-FOV coronal T1 (bright marrow fat is the diagnostic signal for AVN and fracture detection).

5. Optimisation Strategy

5.1 Artifact Reduction by Source

Bowel peristalsis artefact is the dominant motion artefact source in wide-FOV hip and pelvic MRI. The sigmoid colon, small bowel loops, and bladder lie directly anterior to the hip joints in the imaging volume. Peristaltic motion generates phase-encoding ghosting that propagates through the femoral heads and acetabula along the phase direction, potentially simulating labral or marrow signal changes.

Reduction strategies:

• Anterior saturation band over lower abdomen for all wide-FOV coronal sequences
• R-L phase encoding for bilateral coronal sequences (displaces ghosts laterally)
• Short sequence time (parallel imaging) reduces peristaltic ghost accumulation
• Antiperistaltic agents (hyoscine butylbromide/glucagon) where locally available and clinically appropriate — most effective for severe peristalsis but not routinely used
• Patient instruction: voiding before the examination reduces bladder motion

Fat suppression failure at large FOV is more common in hip MRI than in any other MSK protocol because the bilateral wide-FOV pelvis acquisition spans the body's broadest transverse dimension. B0 inhomogeneity is inevitable at the FOV periphery and at fat-air interfaces (bowel gas, lung base, body margin). STIR is the preferred technique precisely for this reason (see Section 4.5).

Metal artefact from THA and surgical hardware: Susceptibility artefact from hip arthroplasty components completely masks adjacent anatomy in standard TSE sequences. At 3T, the artefact extends further than at 1.5T. MARS protocols (SEMAC, WARP, MAVRIC-SL) dramatically reduce metal artefact but require dedicated protocol design and are child pages.

Femoral head-neck junction susceptibility: Even in native hips, the cortical bone-cartilage interface at the femoral head-neck junction generates susceptibility differences detectable on standard sequences. This is not clinically problematic on TSE sequences but may produce artefact on GRE-based sequences (DESS, VIBE/LAVA) if not accounted for in TE selection. For sequence-level protocol optimisation, vendor terminology and artefact management, see the dedicated MRIninja page Gradient Echo (GRE/FLASH) Sequence.

Motion from patient discomfort: Hip pain in the scanner produces involuntary micro-movements that blur the small-FOV sequences. Brief communication between sequences and adequate analgesia before positioning reduces this. For patients who cannot maintain neutral hip position due to acute pain, the examination may be diagnostically limited and this must be documented.

5.2 Protocol Efficiency and Throughput

Standard bilateral protocol: Wide-FOV coronal T1 + STIR + axial T2-FS of pelvis + small-FOV coronal PD-FS + axial oblique PD-FS + sagittal PD-FS = approximately 35–45 minutes.

Abbreviated bilateral protocol (AVN screening): Wide-FOV coronal T1 + STIR (12–15 minutes) — detects AVN and major marrow pathology. Appropriate for bone marrow surveillance in asymptomatic at-risk patients.

Dedicated unilateral labral/FAI protocol: Small-FOV coronal PD-FS + axial oblique PD-FS + sagittal PD-FS ± radial (20–30 minutes unilateral). Does not include the mandatory bilateral wide-FOV component — acceptable when bilateral disease has been excluded on recent prior imaging.

When 3D is worth the time: 3D isotropic PD-FS (SPACE/CUBE/VISTA/DESS at 0.5–0.8 mm isotropic) of the target hip provides MPR, radial reconstruction, and superior labral resolution in a single acquisition. DL reconstruction enables 3D hip acquisition in 5–8 minutes at 3T. Evidence supports superior or comparable labral detection vs. 2D multiplanar [Pos-4].

5.3 Field Strength Considerations

Clinical recommendation: 3T is preferred for labral tear and FAI assessment, cartilage evaluation, and high-resolution tendon imaging. 1.5T is preferred for THA MARS protocols. Both are diagnostically adequate for AVN detection.

6. Contrast Use Principles Specific to Hip MRI

6.1 Non-Contrast Standard Protocol — Sufficient For

The non-contrast standard protocol is diagnostically adequate for: AVN detection and staging (the primary indication); occult femoral neck fracture; marrow infiltration screening (metastases, haematological disease); greater trochanteric pain syndrome / abductor tendinopathy; bone marrow oedema syndrome; trochanteric and iliopsoas bursitis; initial structural assessment in chronic hip pain; follow-up of known AVN.

6.2 Gadolinium Indicated — Hip-Specific Contexts

Intraarticular gadolinium (MR arthrography) — primary indications:

• Suspected labral tear (pre-surgical workup): MR arthrography is the gold standard, providing joint distension that separates the labrum from the acetabulum, enabling detection of small and partial-thickness tears. ACR Appropriateness Criteria rate direct MR arthrography as "usually appropriate" for suspected labral tear [2].
• Articular cartilage assessment (pre-surgical): Intraarticular contrast outlines cartilage surfaces and enters fissures, substantially improving cartilage delamination detection.
• Post-operative labral repair: Joint distension with contrast distinguishes intact repair from recurrent tear.

Intravenous gadolinium:

• Suspected septic arthritis: Post-contrast T1 FS characterises synovial enhancement, bursal involvement, and bone marrow extension of infection.
• Suspected primary bone tumour: Lesion characterisation and extent.
• Inflammatory synovitis / inflammatory arthropathy: Synovial enhancement characterisation.
• AVN perfusion assessment: Dynamic perfusion MRI (DCE-MRI) to assess femoral head perfusion post-core decompression — research/advanced application.
• Equivocal marrow lesion: Enhancement characterises aetiology.

6.3 Post-Contrast Acquisition Timing

Intravenous GBCA: 3–5 minutes post-injection for standard inflammatory/infectious indications. Document injection time in PACS. Pre-contrast T1 fat-suppressed mandatory before injection.

MR arthrography timing: Diagnostic sequences must be acquired within 30–45 minutes after fluoroscopy-guided intraarticular injection, before contrast diffusion out of the joint cavity reduces distension. Patient should perform 10 minutes of mild hip exercise (flexion-extension, circumduction) between injection and scanner entry to distribute the contrast uniformly within the joint.

7. Reporting Essentials

7.1 Interpretation Framework

Hip MRI reporting requires systematic assessment across multiple anatomical compartments, structured differently from knee MRI because of the joint's three-dimensional oblique anatomy.

AVN-first rule: In any patient over 40 years with hip pain, or in any patient with known risk factors (corticosteroid use, alcohol, haematological disease, prior hip trauma), AVN must be actively assessed on the coronal T1 sequence before any other analysis. Missed AVN has severe clinical consequences.

Bilateral comparison: The wide-FOV bilateral coronal T1 and STIR sequences enable direct bilateral comparison at the same slice level. Asymmetry in femoral head signal or morphology is the primary trigger for further analysis.

7.2 Mandatory Reporting Checklist

Femoral heads (bilateral):

• [ ] Bone marrow signal (T1 + STIR): AVN double-line sign, oedema pattern, infiltration
• [ ] Subchondral bone integrity: collapse, fracture line, cyst
• [ ] Femoral head morphology: sphericity, cam deformity alpha angle
• [ ] Articular cartilage: medial and lateral zones

Acetabula (bilateral):

• [ ] Acetabular labrum: superoposterior, anterosuperior, anterior, posterior; tear type, detachment, paralabral cyst
• [ ] Acetabular cartilage: thickness, signal, delamination
• [ ] Acetabular morphology: dysplasia, over-coverage, retroversion
• [ ] Acetabular bone marrow signal

Femoral neck and trochanters:

• [ ] Femoral neck: cortical integrity, fracture lines, stress reaction
• [ ] Greater trochanter: abductor tendon attachment, bursa
• [ ] Lesser trochanter: iliopsoas tendon attachment

Periarticular soft tissues:

• [ ] Gluteus medius and minimus tendons: signal, thickness, tear
• [ ] Iliopsoas tendon: signal, bursitis
• [ ] Greater trochanteric bursa: fluid, thickening
• [ ] Ischiofemoral space: distance, ischiofemoral impingement signs
• [ ] Sciatic nerve (if visible): signal, morphology

Pelvis and proximal femora:

• [ ] Bilateral marrow signal survey: T1 bright (normal fatty marrow) vs T1 dark replacement
• [ ] Sacroiliac joints (visible on wide-FOV): STIR signal, erosion, sclerosis
• [ ] Pelvic bone cortical integrity

Joint cavity:

• [ ] Effusion: size and character
• [ ] Synovial thickening or enhancement (if contrast used)
• [ ] Loose bodies

Technical:

• [ ] Fat suppression quality
• [ ] Side correctly labelled
• [ ] Coil used (body coil vs. surface coil)
• [ ] Metal artefact extent (if hardware present)

7.3 Structured Reporting

Indication → Technique (field strength, coil, sequences with FOV level, contrast if used) → Comparison → Findings (bilateral assessment first, then target hip detail) → Impression → Limitations → Critical communication.

7.4 Incidental Findings — Clinical Decision Framework

Usually benign: Small acetabular labral sulci (posterior-inferior, not anterosuperior); normal physiological variant of acetabular morphology; small subchondral cysts at the weight-bearing zone without cartilage loss; small amounts of joint fluid (< 5 mm joint space distension in adults); iliopectineal bursal communication with joint (normal variant up to 15%).

Requires documentation and follow-up: Indeterminate femoral head or acetabular marrow lesion; pelvic mass extending into hip field of view; unexpected marrow infiltration pattern; sacroiliac joint STIR signal change suggesting active sacroiliitis.

Urgent/clinically important: Unexpected AVN in pre-surgical patient not previously identified; femoral neck insufficiency fracture in unrecognised osteoporosis; unexpected septic arthritis findings; unexpected pelvic neoplasm.

8. MRI Technologist Pearls

8.1 Sequence Order Logic

Recommended standard order:

1. Three-plane localiser — verify both femoral heads included; confirm internal rotation
2. Wide-FOV coronal T1 — bilateral bone marrow baseline; anterior saturation band
3. Wide-FOV coronal STIR — bilateral fluid-sensitive screen
4. Wide-FOV axial T2-FS (optional, bilateral pelvis) — if included in local protocol
5. Small-FOV coronal PD-FS (target hip) — labral and cartilage detail
6. Axial oblique PD-FS (target hip) — femoral head-neck junction and anterior labrum
7. Sagittal PD-FS (target hip) — anterior/posterior labrum, periarticular

Rationale: Wide-FOV bilateral sequences first ensures bilateral disease (particularly AVN) is identified before any coil change or repositioning. If the examination must be abbreviated, the bilateral coronal T1 + STIR alone provides the primary diagnostic value.

8.2 Positioning Tricks

• Internal rotation maintenance: Place a rolled towel between the patient's feet (toes together) before starting. This maintains mild internal rotation and prevents the natural external rotation drift during the examination.
• Saturation band position check: Verify the anterior saturation band is placed over the lower abdomen (small bowel, sigmoid, bladder anterior to hip joints) and does NOT overlap the anterior femoral head or hip joint capsule. Incorrect placement saturates femoral head signal.
• Axial oblique angulation verification: After planning the axial oblique, review a test image before acquiring the full series. If the femoral head appears elliptical rather than circular, the angulation is incorrect — adjust and re-plan.
• Coil change midway: If using body coil for bilateral and surface coil for unilateral — do the coil change between step 4 and step 5 and re-localise. The surface coil position must be verified on the localiser before starting the small-FOV sequences.
• Document which hip is symptomatic: Confirm with the patient which hip is the primary complaint before starting. The small-FOV dedicated sequences are acquired on the symptomatic side; this must be documented.

8.3 Fast Salvage Protocol

Core minimum (bilateral marrow screening): Wide-FOV Coronal T1 + STIR = 9–13 minutes; complete bilateral AVN, fracture, and marrow disease screening.

8.4 Common Avoidable Errors

9. Quality Control Checklist

Coverage:

• [ ] Bilateral wide-FOV sequences include both complete femoral heads
• [ ] Bilateral coverage extends from ASIS superiorly to lesser trochanter inferiorly
• [ ] Small-FOV sequences cover complete labral circumference of target hip
• [ ] Axial oblique coverage extends from superior to inferior acetabular rim

Image quality:

• [ ] Wide-FOV T1: bright marrow signal bilaterally; no fat suppression applied
• [ ] Wide-FOV STIR: uniform fat nulling bilaterally (subcutaneous fat dark); TI correct for field strength
• [ ] Small-FOV sequences: fat suppression uniform; labrum clearly delineated
• [ ] Axial oblique: femoral head appears circular (correct angulation confirmed)
• [ ] No significant bowel peristalsis ghosting through femoral heads on bilateral sequences

Sequence completeness:

• [ ] Wide-FOV coronal T1: acquired, reviewed
• [ ] Wide-FOV coronal STIR: acquired, fat suppression confirmed
• [ ] Small-FOV coronal PD-FS: acquired
• [ ] Axial oblique PD-FS: acquired, angulation verified
• [ ] Sagittal PD-FS: acquired

Contrast (if used):

• [ ] Pre-contrast T1-FS acquired before injection
• [ ] Injection time and type documented
• [ ] STIR NOT acquired post-contrast

Labelling:

• [ ] Right/left hip correctly labelled on all small-FOV series
• [ ] Wide-FOV series correctly oriented (R/L markers)
• [ ] Patient identifiers correct

11. Evidence Gaps and Ongoing Debate

Non-contrast MRI vs. MR arthrography for labral tears: ACR Appropriateness Criteria maintain MR arthrography as "usually appropriate" for suspected labral tear while non-contrast MRI remains "may be appropriate." At 3T, reported sensitivity of non-contrast MRI for labral tears ranges from 66% to 90% depending on tear size, reader experience, and sequence quality. A prospective randomised trial comparing clinical outcomes (not just lesion detection) for MR arthrography vs. 3T non-contrast MRI in pre-surgical labral assessment does not exist.

Radial sequences — diagnostic necessity or technical preference: Radial imaging provides circumferential alpha angle measurement and complete labral assessment at all clock positions but has not demonstrated diagnostic superiority over a well-executed multiplanar protocol in randomised trials.

Wide-FOV bilateral vs. unilateral-only protocols: Whether all hip MRI examinations require bilateral wide-FOV sequences or whether clinical targeting (symptomatic side only) is acceptable is debated. Bilateral AVN rate (50–80%) supports bilateral imaging, but unilateral protocols are more efficient and may be sufficient when clinical suspicion is very low.

3D isotropic protocols replacing 2D multiplanar: Evidence supports comparable or superior performance of 3D sequences in research settings, but widespread clinical adoption is limited by acquisition time, reader calibration, and vendor platform variability.

AI/DL acceleration for hip MRI: Early evidence supports maintained diagnostic quality with 30–50% time reduction at 3T. Multi-site validation across clinical populations, including obese patients and those with hardware, is needed.

STIR vs. Dixon for wide-FOV bilateral hip sequences: STIR is widely recommended; Dixon provides higher SNR with equivalent B0 robustness at modern field strengths. Head-to-head clinical evidence in the pelvis/hip context is limited.

12. Evidence-Based References

A. Guidelines / Consensus / Society Recommendations

[1] Flug JA, Fox MG, Bartolotta RJ, et al. ACR Appropriateness Criteria® Acute Hip Pain: 2024 Update. J Am Coll Radiol. 2025;22(5S). PMID: 40409883. (High — Guideline) Relevance: Acute hip pain imaging strategy including occult fracture.

[2] Jawetz ST, Fox MG, et al. ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update. J Am Coll Radiol. 2023;20(5):S120–S135. PMID: 37236751. (High — Guideline) Relevance: Labral tear, FAI, cartilage, and PVNS imaging strategy.

[3] Ha AS, Chang EY, et al. ACR Appropriateness Criteria® Osteonecrosis: 2022 Update. J Am Coll Radiol. 2022;19(11S):S409–S416. PMID: 36436966. (High — Guideline) Relevance: AVN detection and staging; bilateral examination standard.

[4] ESSR Musculoskeletal Working Group. ESSR MRI Protocols — Standard Hip. ESSR. (High — Consensus protocol) Relevance: European reference protocol for hip MRI.

B. Important Original Studies

[7] Zlatkin MB, Pevsner D, Sanders TG, et al. Acetabular labral tears and cartilage lesions of the hip: indirect MR arthrographic correlation. AJR. 2010;194(3):709–714. PMID: 20173148. (Moderate) Relevance: Documents anterosuperior labral tear prevalence and indirect arthrographic technique.

[8] Ito K, Minka MA 2nd, Leunig M, et al. Femoroacetabular impingement and the cam-effect. J Bone Joint Surg Br. 2001;83(2):171–176. PMID: 11284563. (Moderate) Relevance: Foundational FAI cam morphology description and alpha angle measurement standard.

C. Technical MRI Papers

[5] Del Grande F, et al. Fat-suppression techniques for 3-T MR imaging. RadioGraphics. 2014;34:217–233. PMID: 24428290. (Technical) Relevance: Fat suppression technique comparison for large FOV MSK.

[DL-hip] Herrmann J, et al. Image Quality and Diagnostic Performance of Accelerated 2D Hip MRI with Deep Learning Reconstruction. Diagnostics. 2023;13(20):3241. (Technical) Relevance: DL reconstruction for hip MRI quality maintenance with scan time reduction.

[Pos-4] Tian CY, et al. Comparison of 2D, 3D, and radially reformatted MR images in hip pathology. Skeletal Radiol. 2021;50(2). (Moderate) Relevance: 3D vs 2D comparative evidence for labral and cartilage hip assessment.

D. Landmark Historical References

[9] Mitchell DG, Rao VM, Dalinka MK, et al. Femoral head avascular necrosis: correlation of MR imaging, radiographic staging, radionuclide imaging, and clinical findings. Radiology. 1987;162(3):709–715. PMID: 3809484. (High — Landmark) Relevance: Foundational MRI study establishing AVN detection stages and the double-line sign.

End of document — MRI HIP Generic Standard Protocol — MRIninja Master Page v1.0 — April 2026

This document is designed to serve as the reference base for all child pages dedicated to specific hip pathologies, clinical indications and dedicated protocols.