High Yield Overview

Arthrography Techniques

Contrast-Enhanced Joint Imaging for Intra-articular Pathology

DirectContrast injected into joint (gold standard)

IndirectIV contrast with exercise diffusion

Gd-DTPAGadolinium diluted for MR arthrography

95%Sensitivity for labral tears (direct MRA)

CT-ACT arthrography for bony detail

20mLTypical shoulder injection volume

30minImage within 30 minutes of injection

1:200Gadolinium dilution ratio for MRA

Arthrography Modalities

Direct MR Arthrography: Joint injection (Gd-DTPA diluted) + MRI. Best for labral tears, partial cuff tears, capsular pathology

Indirect MR Arthrography: IV gadolinium + exercise + MRI. Non-invasive but inferior to direct

CT Arthrography: Joint injection (iodinated contrast) + CT. For bony detail, MRI contraindication

Conventional Arthrography: Joint injection + fluoroscopic radiographs. Largely replaced by MRA/CTA

Key: Direct MRA is the gold standard for intra-articular soft tissue pathology; CT arthrography excels at bony assessment

Critical Must-Knows

Direct MR arthrography (MRA): gadolinium is INJECTED directly into the joint under fluoroscopic or ultrasound guidance, then MRI is performed.
Indirect MR arthrography: gadolinium is given INTRAVENOUSLY, then the patient exercises to promote diffusion of contrast into the joint.
Direct MRA is the gold standard for labral pathology — distension of the joint with contrast separates labral tissue from the glenoid, improving tear detection.
CT arthrography uses iodinated contrast injected into the joint, followed by CT — excellent for bony detail (glenoid bone loss, Hill-Sachs) and in patients with MRI contraindications.
The key indication for arthrography over non-contrast MRI is the improved detection of partial-thickness tears, labral tears, and capsular pathology.

Examiner's Pearls

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Direct MRA sensitivity for labral tears (95%) is significantly higher than non-contrast MRI (75-80%).
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Gadolinium for MRA is diluted to approximately 1:200 (2mmol/L) — undiluted gadolinium is TOO CONCENTRATED and causes signal loss on T1-weighted images.
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Images must be acquired within 30-60 minutes of injection — contrast absorption reduces diagnostic quality rapidly.
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CT arthrography is the preferred alternative when MRI is contraindicated (pacemaker, metal) and is superior for assessing glenoid bone loss.
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The sublabral recess and sublabral foramen are NORMAL VARIANTS that mimic labral tears — knowing these prevents surgical over-treatment.

Exam Warning

Arthrography is commonly examined in the context of shoulder instability assessment (labral tears, glenoid bone loss), rotator cuff assessment (partial-thickness tears), and hip labral pathology. You must know: the technique of direct vs indirect arthrography, the gadolinium dilution ratio, time constraints for imaging, and the specific advantages of MR vs CT arthrography. Classic traps include confusing normal sublabral variants with tears and not knowing when CT arthrography is preferred over MRA.

Mnemonic

INJECTDirect MR Arthrography Technique

Image-guided needle placement (fluoroscopy or US)

A 22-gauge spinal needle is placed into the joint under fluoroscopic or ultrasound guidance to confirm intra-articular position

Normal saline + gadolinium preparation

Gadolinium (Gd-DTPA) is diluted 1:200 in saline (2mmol/L). Undiluted gadolinium is too concentrated and paradoxically reduces T1 signal

Joint distension with contrast

Sufficient volume is injected to distend the joint capsule, separating intra-articular structures. Shoulder: 10-20mL, hip: 10-15mL, wrist: 3-5mL

Expedite to MRI scanner (within 30 minutes)

Images must be acquired within 30-60 minutes — contrast is absorbed by synovium progressively, degrading diagnostic quality

Coils and sequences (T1-weighted with fat suppression)

T1-weighted fat-suppressed sequences are the mainstay — gadolinium produces bright signal on T1. T2 sequences complement for effusion/oedema

Traction and positioning for specific views

ABER position (abduction external rotation) for the shoulder improves inferior labral and undersurface cuff tear visualisation

Memory Hook:INJECT: the six steps of direct MR arthrography — from needle to imaging.

Mnemonic

DISCAdvantages of Direct MRA

Distension separates structures

Joint capsule distension with contrast mechanically separates the labrum from the glenoid, capsule from bone, and tendon layers — improving tear detection

Improves sensitivity for partial tears

Contrast insinuates into partial-thickness tears (undersurface cuff tears, labral tears) that might be invisible on non-contrast MRI

Signal on T1 fat-sat highlights pathology

Gadolinium is bright on T1 — contrast-filled tears become conspicuous against the dark background of fat-suppressed tendons and labrum

Capsular pathology revealed

Joint distension demonstrates capsular redundancy (MDI), HAGL lesions, capsular adhesions (adhesive capsulitis), and loose bodies

Memory Hook:DISC: MRA acts like putting dye in a DISC to find cracks — distension reveals hidden tears.

Mnemonic

BUFORDNormal Labral Variants

Buford complex

Complete absence of the anterosuperior labrum with a thick, cord-like middle glenohumeral ligament. Not pathological — no treatment required

Undercutting (sublabral recess)

The superior labrum may have a normal recess (meniscoid attachment) that can mimic a SLAP tear. Deepest at 11-1 o'clock position

Foramen (sublabral foramen)

An opening between the anterosuperior labrum and glenoid (1-3 o'clock) — present in approximately 12-18% of shoulders. Normal variant, not a Bankart

Orientation of the labrum

The labrum has variable normal morphology: triangular, rounded, flat, or cleaved. Variation alone does not indicate pathology

Recesses and folds (normal)

Normal synovial recesses (axillary pouch, subscapularis bursa) should not be confused with pathological collections

Distinguish from tears

Smooth margins, consistent location (anterosuperior), and absence of paralabral cysts differentiate normal variants from true tears

Memory Hook:BUFORD complex: the most important normal variant to know — absent anterosuperior labrum with a thick cord-like MGHL.

Overview

Arthrography is the introduction of contrast material into a joint to improve the diagnostic imaging of intra-articular structures. It represents one of the most valuable diagnostic techniques for evaluating labral pathology, partial-thickness rotator cuff tears, cartilage lesions, loose bodies, and capsular abnormalities.

The fundamental principle is straightforward: by filling the joint with contrast, intra-articular structures are outlined and separated from one another. A tear that might be invisible on non-contrast MRI becomes conspicuous when contrast material insinuates into the defect, creating a high-contrast interface between the contrast and the adjacent tissue.

Direct vs Indirect Arthrography

Direct arthrography involves percutaneous injection of contrast directly into the joint under image guidance (fluoroscopy or ultrasound). This provides consistent, controlled joint distension and high intra-articular contrast concentration. Indirect arthrography involves intravenous injection of gadolinium, followed by 10-15 minutes of gentle exercise to promote contrast diffusion across the synovial membrane into the joint. Indirect MRA is non-invasive but provides less reliable joint distension and lower intra-articular contrast concentration. Direct MRA is superior and is the technique of choice when arthrography is indicated.

MR vs CT Arthrography

MR arthrography uses dilute gadolinium (bright on T1) and provides excellent soft tissue contrast — ideal for labral tears, partial cuff tears, cartilage defects, and capsular pathology. CT arthrography uses dilute iodinated contrast and provides superior bony detail — ideal for glenoid bone loss quantification, Hill-Sachs measurement, and osteochondral defects. CT arthrography is the preferred alternative when MRI is contraindicated (pacemaker, non-MRI-conditional implants) or when bony detail is the primary clinical question.

Clinical Imaging

Imaging Gallery

MR arthrography demonstrating contrast-enhanced visualisation of intra-articular structures — MR arthrography demonstrating the effect of direct contrast injection into the joint. The dilute gadolinium (bright on T1-weighted images) fills the joint space, outlining and separating intra-articular structures such as the labrum, capsule, and articular surfaces.Credit: Open-i (NIH) (Open Access (CC BY))

CT arthrography demonstrating bony and soft tissue detail after intra-articular contrast injection — CT arthrography demonstrating the high-resolution bony detail achieved when iodinated contrast outlines intra-articular structures. CT arthrography excels at quantifying glenoid bone loss (best-fit circle method), measuring Hill-Sachs defects, and detecting osteochondral lesions.Credit: Open-i (NIH) (Open Access (CC BY))

Systematic Approach

Systematic Arthrogram Assessment

Systematic Arthrographic Interpretation

Structure	Normal Appearance	Pathological Findings
Labrum	Triangular or rounded, firmly attached to glenoid rim, smooth margins	Tear: contrast extending into or beneath the labrum. Bankart: inferior labral detachment. SLAP: superior labral tear with or without biceps anchor involvement
Rotator cuff	Intact tendon without contrast extension into the tendon substance	Full-thickness tear: contrast extends from joint into subacromial space. Partial tear (articular surface): contrast insinuates into undersurface of tendon without full extension through
Biceps tendon	Located in the bicipital groove, intimately associated with the rotator interval	Biceps subluxation: tendon displaces medially over the lesser tuberosity. Sheath tear: contrast extends into the bicipital sheath
Capsule and ligaments	Capsule smoothly lines the joint. Glenohumeral ligaments visible as thickenings	HAGL: contrast extending beyond the humeral attachment site. Capsular redundancy: excessive volume in inferior pouch (MDI)
Articular cartilage	Smooth, uniform thickness articular surface without contrast undercutting	Chondral defect: contrast replaces or undercuts the cartilage surface. Grading by depth and area
Loose bodies	No filling defects within the contrast-filled joint	Filling defect: contrast surrounds a dense rounded opacity (chondral or osteochondral loose body). Best seen on CT arthrography

Joint-Specific Applications

Shoulder MR Arthrography

The shoulder is the most common joint for arthrography and the most frequently tested in the fellowship exam. Direct MR arthrography of the shoulder is the gold standard for:

Labral tears: Bankart (anterior-inferior), reverse Bankart (posterior), SLAP (superior), and HAGL lesions
Partial-thickness rotator cuff tears: Particularly articular-surface partial tears (Ellman classification) that are difficult to see on non-contrast MRI
Capsular pathology: Multidirectional instability (increased capsular volume), adhesive capsulitis (decreased volume)
Loose bodies: Detected as filling defects within the contrast-filled joint

Injection technique: Under fluoroscopy or ultrasound guidance, a 22-gauge spinal needle is advanced into the glenohumeral joint (anterior approach, targeting the junction of the middle and lower thirds of the glenoid). A small test injection of iodinated contrast confirms intra-articular position on fluoroscopy. Then 10-20mL of dilute gadolinium (1:200) is injected.

Key sequences: T1-weighted fat-suppressed images in three planes (axial, coronal oblique, sagittal oblique) are the mainstay. T2-weighted sequences complement by showing oedema. The ABER position (abduction and external rotation) is obtained in the axial plane to improve visualisation of the anterior-inferior labrum and anterior band of the inferior glenohumeral ligament.

Sensitivity for labral tears: Direct MRA achieves 90-95% sensitivity and 85-90% specificity for labral tears, compared to 75-80% sensitivity for non-contrast MRI.

Evidence Base

Direct MR Arthrography for Labral Tears

Meta-Analysis

Smith TO, Drew BT, Toms AP • Clinical Radiology (2012)

Key Findings:

Direct MRA had pooled sensitivity of 92% and specificity of 86% for glenohumeral labral tears.
Non-contrast MRI had pooled sensitivity of 76% and specificity of 87%.
Direct MRA was significantly superior for detecting partial tears and SLAP lesions.

Clinical Implication: Direct MRA is the investigation of choice when labral pathology is suspected — its sensitivity advantage over non-contrast MRI is clinically significant.

Limitation: Requires an invasive injection procedure (risks: infection, contrast reaction, vasovagal). Image quality is operator-dependent.

Source: Smith TO et al. Clin Radiol 2012;67(2):149-58

MRA vs Non-Contrast MRI for Rotator Cuff

Systematic Review

de Jesus JO, Parker L, Frangos AJ, Nazarian LN • American Journal of Roentgenology (2009)

Key Findings:

For full-thickness rotator cuff tears: MRA sensitivity 95%, non-contrast MRI sensitivity 91% — no significant difference.
For partial-thickness tears: MRA sensitivity 83%, non-contrast MRI sensitivity 67% — significant advantage for MRA.
The advantage of MRA was greatest for articular-surface partial tears (Ellman types).

Clinical Implication: MRA adds most value for PARTIAL-THICKNESS cuff tears, particularly articular-surface tears. For full-thickness tears, non-contrast MRI is adequate.

Limitation: Full-thickness tear detection is similar — the invasive injection is not justified solely for full-thickness tear assessment.

Source: de Jesus JO et al. AJR 2009;192(6):1701-7

MRA is most valuable for partial tears and labral lesions.

Australian Context

In Australia, arthrography is performed in radiology departments by radiologists or musculoskeletal subspecialty radiologists, with referral from orthopaedic surgeons or sports medicine physicians. Direct MR arthrography is the standard technique for shoulder labral assessment and hip labral evaluation in most Australian imaging centres.

The injection component of the arthrogram is typically performed under fluoroscopic or ultrasound guidance. Australian radiology departments use Gadopentetate dimeglumine (Magnevist) or similar GBCAs diluted to approximately 2mmol/L (1:200) for MR arthrography. The imaging must be completed within 30-60 minutes of injection, requiring coordinated scheduling between the fluoroscopy suite and the MRI scanner.

CT arthrography is used as an alternative when MRI is contraindicated (MRI-unsafe implants, pacemakers) or when bony detail is the primary clinical question (glenoid bone loss quantification for Latarjet planning). Australian orthopaedic practice increasingly requests 3D CT arthrography with en-face glenoid views for preoperative planning in recurrent shoulder instability.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 25-year-old man has recurrent anterior shoulder dislocations. His non-contrast MRI shows an equivocal anterior labral finding. You are considering further imaging."

EXCEPTIONAL ANSWER

I would request a direct MR arthrogram of the shoulder. This is the investigation of choice in this clinical scenario for several important reasons: The clinical problem: This patient has recurrent anterior instability, and the clinical question is whether he has a Bankart lesion (labral tear with or without bony involvement) and the extent of any associated glenoid bone loss. Non-contrast MRI has a sensitivity of only 75-80% for labral tears — the equivocal finding may represent a true tear that is insufficiently distended to be confidently identified. Why direct MRA is superior: (1) Joint distension mechanically separates the labrum from the glenoid, making tears that are appositional (in contact) become visible. (2) Contrast insinuates into the tear plane, creating a high-contrast T1 signal within the defect. (3) Direct MRA achieves 90-95% sensitivity for labral tears vs 75-80% for non-contrast MRI. (4) The ABER position (abduction and external rotation) stretches the anterior-inferior labrum and further improves detection of anterior labral tears and AIGHL insufficiency. Additionally, I would request a CT arthrogram with 3D reconstruction and en-face glenoid views to quantify any glenoid bone loss. Glenoid bone loss of more than 20-25% would change my surgical approach from a Bankart repair to a bone augmentation procedure (Latarjet). The CT arthrogram can be performed at the same session as the MRA injection — after the gadolinium MRA images are obtained, dilute iodinated contrast can be injected into the joint and CT performed. Normal variants to be aware of: I would ask the radiologist to specifically comment on whether any anterosuperior labral finding represents a sublabral foramen (present in 12-18%) or Buford complex, rather than a pathological tear.

KEY POINTS TO SCORE

Direct MRA: 90-95% sensitivity for labral tears vs 75-80% for non-contrast MRI

Joint distension separates labrum from glenoid — reveals appositional tears

ABER position improves anterior labral and AIGHL visualisation

CT arthrography with 3D en-face views quantifies glenoid bone loss

More than 20-25% bone loss changes management from Bankart to Latarjet

COMMON TRAPS

✗Accepting the equivocal non-contrast MRI as 'normal' in a clinically unstable shoulder

✗Not requesting CT arthrography for bone loss assessment

✗Not mentioning normal variants (sublabral foramen, Buford complex)

✗Requesting indirect MRA instead of direct (direct is superior)

VIVA SCENARIOStandard

EXAMINER

"A 30-year-old woman presents with deep groin pain and mechanical catching in her hip. You suspect a labral tear. Her plain radiographs show cam morphology."

EXCEPTIONAL ANSWER

I would request a direct MR arthrogram of the hip. The clinical presentation (deep groin pain, mechanical catching in a young adult with cam morphology on radiographs) is highly suggestive of femoroacetabular impingement (FAI) with an associated labral tear and possibly early cartilage damage. Why direct hip MRA: Non-contrast MRI has a sensitivity of only 66% for acetabular labral tears. Direct MRA improves this to approximately 87%, which is critical for confirming the diagnosis and planning for hip arthroscopy. The contrast provides: (1) Labral assessment: contrast extending into or beneath the labral substance confirms a tear. Anterior and anterosuperior tears are most common in cam-type FAI. (2) Cartilage assessment: chondral delamination (where a sheet of cartilage separates from subchondral bone) is detected by contrast undercutting the cartilage surface — this is the 'wave sign' on MRA. (3) Cam morphology quantification: the alpha angle can be measured on radial sequences (more than 55-60 degrees is abnormal). The asphericity of the femoral head-neck junction is best assessed on radial MRA sequences. (4) Associated findings: paralabral cysts (confirm chronic labral tear), ligamentum teres integrity, synovitis, and joint effusion. Injection technique: Under fluoroscopic guidance, a 22-gauge spinal needle is inserted via an anterior approach into the hip joint, targeting the femoral head-neck junction. Position is confirmed with a small test injection of iodinated contrast. Then 10-15mL of dilute gadolinium is injected. The key sequences include T1-weighted fat-suppressed images in axial, coronal, and sagittal planes, plus radial sequences centred on the femoral neck axis for alpha angle measurement. Surgical planning: If a labral tear is confirmed on MRA, and the patient has failed conservative management (physiotherapy, activity modification, NSAIDs for 3-6 months), I would discuss hip arthroscopy for labral repair and cam resection (osteochondroplasty).

KEY POINTS TO SCORE

Direct hip MRA sensitivity 87% for labral tears vs 66% for non-contrast MRI

Anterior/anterosuperior tears are most common in cam-type FAI

Wave sign: chondral delamination detected by contrast undercutting cartilage

Alpha angle measured on radial sequences (more than 55-60 degrees = cam morphology)

Injection via anterior approach, fluoroscopic guidance, 10-15mL dilute gadolinium

COMMON TRAPS

✗Using non-contrast MRI only (inadequate sensitivity for labral tears)

✗Not mentioning cartilage assessment (chondral delamination is critical for prognosis)

✗Not knowing the alpha angle or its measurement technique

✗Not requesting MRA before proceeding directly to arthroscopy

VIVA SCENARIOChallenging

EXAMINER

"An examiner asks you to compare direct MR arthrography, indirect MR arthrography, and CT arthrography. When would you choose each?"

EXCEPTIONAL ANSWER

I will compare these three modalities across technique, strengths, limitations, and indications. Direct MR arthrography: Technique — joint injection of dilute gadolinium under image guidance, followed by MRI within 30-60 minutes. Strengths — gold standard for labral tears (sensitivity 92%), best for partial-thickness rotator cuff tears, capsular pathology, and intra-articular loose bodies. Provides controlled joint distension that separates structures. Limitations — invasive (injection risks: infection, vasovagal, allergy), operator-dependent injection technique, requires coordinated scheduling (fluoroscopy then MRI). Indications — suspected labral tear (shoulder or hip), partial-thickness cuff tear assessment, instability workup, post-surgical evaluation (repaired labrum). Indirect MR arthrography: Technique — intravenous gadolinium injection followed by 10-15 minutes of gentle exercise, then MRI. Gadolinium diffuses across the synovium into the joint. Strengths — non-invasive (no joint injection), simpler logistics. Limitations — inferior to direct MRA: less reliable joint distension, lower intra-articular gadolinium concentration, variable contrast distribution depending on synovial permeability and exercise compliance. Sensitivity for labral tears is approximately 80% (vs 92% for direct). Indications — when arthrography is desired but the patient refuses or cannot undergo joint injection, or when scheduling constraints prevent coordinated injection and MRI. Inferior to direct MRA and not preferred when direct technique is available. CT arthrography: Technique — joint injection of dilute iodinated contrast under fluoroscopy, followed by CT scanning. Strengths — superior spatial resolution for bone (0.3-0.5mm), excellent for glenoid bone loss quantification (3D reconstruction, best-fit circle method), superior for osteochondral lesions, Hill-Sachs sizing. Available when MRI is contraindicated. Quick scan time (minutes vs 30-45 min for MRI). Limitations — ionising radiation, inferior soft tissue contrast compared to MRI, cannot assess bone marrow oedema or tendon signal. Indications — (1) glenoid bone loss quantification in recurrent instability (gold standard), (2) MRI contraindication (pacemaker, metal), (3) osteochondral defect assessment, (4) when bony detail is the primary question. In summary: Direct MRA is the gold standard for soft tissue intra-articular pathology. CT arthrography is the gold standard for bony assessment. Indirect MRA is the non-invasive compromise when direct injection is not feasible.

KEY POINTS TO SCORE

Direct MRA: gold standard for labral tears and partial cuff tears (sensitivity 92%)

Indirect MRA: non-invasive but inferior (sensitivity 80%) — only when direct injection cannot be performed

CT arthrography: gold standard for bony assessment (glenoid bone loss, Hill-Sachs) and when MRI is contraindicated

Both direct MRA and CTA require invasive injection

CT arthrography can be combined with MRA in the same session (dual arthrogram)

COMMON TRAPS

✗Not knowing the technique differences (injection vs IV contrast vs CT)

✗Stating indirect MRA is equivalent to direct (it is significantly inferior)

✗Not mentioning CT arthrography as the gold standard for glenoid bone loss

✗Not knowing the specific indications for each modality