Transcript MR arthrography of the shoulder: Techniques and role in

MR arthrography
of the shoulder:
Techniques and role in
diagnosis of rotator cuff
and labral pathology
Werner Harmse
July 2011
MR shoulder arthrogram
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Technique whereby injection of contrast
media into the joint allows for evaluation of
capsule and internal joint structures.
Originally performed using plain
radiography.
Now injection of gadolinium allows MR
arthrography.
CT arthrograms can also be performed.
Technique
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Fluoroscopically guided anterior approach is
most widely performed.
Perform routine preparation
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Correct patient
Correct side
No iodine allergies
Explain procedure to patient. ? Informed consent
Confirm indication
Indications
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Assessment of integrity of rotator cuff
Evaluation of shoulder instability
Diagnosis of labral pathology
Diagnosis of adhesive capsulitis
Technique
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Sterile procedure
Fluoroscopically guided
Obtain control images of shoulder
– Patient supine, AP view
– Arm in external and internal rotation
– Angle tube to view acromion in profile –
clear visualisation of sub-acromial space
– Evaluate for calcium deposition in
tendons
Positioning
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Supine position creates oblique
orientation of glenoid surface.
Posterior glenoid overlaps
humeral head
Anterior glenoid is however
medial of humeral head.
Thus needle directed AP at
humeral head will not injure
anterior labrum
External rotation exposes a
larger articular surface
anteriorly
Placing a sandbag in the
patient’s hand may help
maintain the position
Technique
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Determine skin entry site
Just lateral to the medial
cortex of the humeral head
(never medial)
At junction of middle and
lower third
Ideally central in
fluoroscopic image
Locally anaethetise skin and
sub-cutaneous tissue
Technique
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Prepare contrast whilst allowing local anaestethic to take
effect (can also be done before procedure starts)
Our protocol:
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20 ml syringe
10 ml sterile water
5 ml iodine based non-ionic LOCM (eg.Ultravist)
5 ml lignocaine
0.1 ml gadolinium
Other:
– Test injection with 1-2 ml of lignocaine
– Contrast: 10 ml saline, 10 ml Iodine LOCM, 0.1 ml gadolinium,
0.3 ml 1:1000 adrenaline
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Syringe connected to connecting catheter(line)
Technique
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Advance needle (usually 20G
spinal needle with stylet) in
direct AP direction posteriorly.
Continue until contact with
humeral head.
Consider test injection with
lignocaine.
Should only meet low
resistance when in joint space
If high resistance – possibly in
hyaline cartilige – carefully
manipulate needle by rotation
and minimal retraction (few
mm)
Loss of resistance indicates
intra-articular or bursal location
Technique
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Inject iodinated contrast to
distinguish between intraarticular and bursal location
Intra-articular contrast will
collect in gleno-humeral
joint space
If intra-articular position is
confirmed – continue with
proper contrast injection
Usually inject between 14 –
16 ml of contrast,
depending on patient and
pathology.
Advantages
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Joint distension, outlining intraarticular structures
Improved detection of tears, including
articular surface partial tears
Demonstration of communication
between joint and extra-articular
abnormalities eg. Paralabral cysts and
bursae.
Disadvantages and
pitfalls
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Risks assoc with needle placement into
joint: infection, haemorrhage, synovial
reaction.
Avoid oblique position – glenoid in profile –
aiming for joint space places the labrum at
risk
Correct needle positioning is essential
– Extra articular contrast can complicate findings
on MR and simulate tears
Posterior approach
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When suspecting anterior pathology.
Avoids the interpretative difficulties that may be associated
with anterior extracapsular contrast extravasation
Aim for the inferomedial quadrant of humeral head within
boundary of anatomic neck (interrupted line).
Other techniques
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Advance needle with
stylet removed and
lignocaine placed in
needle hub – drop in
fluid level indicates
intra-articular position
Internal rotation when
needle against humeral
head – facilitates intraarticular placement
Ultrasound guided
approach
MR technique
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Three plane T1 with fat sat
T2 with fat sat axial and coronal oblique (Consider
Ax GRE to evaluate for calcification)
Sagittal oblique T1/PD without fat suppression
Some protocols suggest pre contrast T2 sequences.
– Detection of intra-substance and bursal surface tears.
– Pre-existing fluid collections and cysts
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Coronal oblique parallel to supraspinatus tendon
(not muscle)
Sagittal oblique perpendicular to glenoid surface
(ABER – Abduction and External rotation sometimes
used for evaluation of anterior and inferior GHLs)
Other techniques
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Inject only water, no gadolinium
– Achieves effect of distension
– Need to use T2 sequences
– Difficult to distinguish between small full thickness and
partial tears
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Indirect arthrogram
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1 mmol/kg Gd IV
Exercise joint for 5 to 5 minutes
Gd passes into joint space
Can perform T1 images
Joint however not distended
Beware – extra-articular structures will also enhance
Rotator cuff tears
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Arthrography improves detection of tears as
the joint is being distended and contrast
forced into small defects.
T1 (quicker) sequences with improved SNR
can be used
Diagnoses full thickness tears and articular
surface partial thickness tear
Not of value in intra-substance or bursal
surface partial thickness tears
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Full-thickness tear will demonstrate the
gadolinium contrast solution extending first
through a defect in the cuff and then into
the subacromial-subdeltoid bursa.
Articular-surface partial-thickness tears
show a focal extension of the contrast
solution into the substance of the tendon.
Fat suppression is necessary as peribursal
fat may mimic contrast.
Full thickness rotator cuff tear with
contrast extending through the
supraspinatus tendon into the subacromial sub-deltoid bursa.
Full thickness tear
(A) T1-weighted image with fat saturation and (B) T2weighted image with fat saturation depict contrast within the
joint (yellow arrows). Note the presence of contrast within
the subacromial-subdeltoid bursa (red arrows) due to the
full-thickness tear within the distal supraspinatus tendon
(green arrow)
Partial thickness tear articular surface
A) T1-weighted image with fat saturation and (B) T2-weighted
image with fat saturation depict a partial-thickness articular
surface tear (red arrows) of the supraspinatus tendon. Contrast
enters the tear, and the tear is seen as a hyperintense area on
both pulse sequences. Although there is a small amount of
hyperintense fluid in the subacromial-subdeltoid bursa on the T2weighted image, no contrast enters the bursa.
Intra substance tear
(A) T1-weighted image with fat saturation and (B) T2-weighted image with fat
saturation depict contrast within the joint (yellow arrows). Note the intrasubstance
tear (red arrow) of the distal supraspinatus tendon, seen as a hyperintense zone
on the T2-weighted image. Note that contrast does not enter this area since the
tear does not communicate with the articular surface of the tendon. There is
hyperintense fluid in the subacromial-subdeltoid bursa on the T2-weighted image,
but this area is hypointense on the T1-weighted image. This fluid should not be
confused with contrast in the bursa.
Subscapularis tendon
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Subscapularis tendon tears are common.
They can result from acute trauma on an adducted arm in
hyperextension or in external rotation. They can result from an
anterior shoulder dislocation, they can be associated with massive
tears of the rotator cuff and with biceps tendon dislocations, or they
can result from subcoracoid impingement.
Tears of the subscapularis tendon are best evaluated on axial MRIs,
where the entire length of the tendon is evident or on sagittal
images.
The tears are seen best on T2W images or on T1W images after
intra-articular gadolinium injection.
Tears may be seen as tendon discontinuity, contrast media entering
into the tendon substance, intrasubstance abnormal tendon signal,
abnormal caliber of the tendon, and abnormal position of the tendon.
Other helpful accessory signs are the leakage of intra-articular
contrast material under the insertion of the subscapularis tendon
onto the lesser tuberosity and fatty atrophy of the subscapularis
muscle, usually localized at the cranial aspect of the muscle and seen
as high signal intensity streaks on T1W images.
Abnormalities in the course of the long head of the biceps tendon
(subluxation or dislocation) usually are associated with subscapularis
tendon tears. They often extend into the subscapularis muscle.
A, T1 fat-suppressed axial shoulder MR arthrogram. The bicipital
groove is empty. The biceps tendon (arrowhead) is located over
the anterior glenohumeral joint and posterior to the subscapularis
tendon (arrow), which has been avulsed from its attachment to the
lesser tuberosity of the humerus. B, T1 fat-suppressed coronal
oblique shoulder MR arthrogram. The biceps tendon (arrowheads)
is dislocated medially overlying the shoulder joint.
Labral anatomy and
pathology
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The glenoid labrum is a
fibrocartilaginous structure that
attaches to the glenoid rim and
is about 4 mm wide.
Anteriorly, the glenoid labrum
blends with the anterior band
of the inferior glenohumeral
ligament. Superiorly, it blends
with the biceps tendon and the
superior glenohumeral
ligament.
It is usually rounded or
triangular on cross-sectional
images.
Variants
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Sublabral recess
12’o clock
Sub-labral foramen
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2’o clock position. Anterior to biceps tendon
Buford complex
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Cord-like thickening
of middle
glenohumeral
ligament with
absence of anterior
superior labrum.
Anterior labrum
Bankart lesion
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The Bankart lesion is the most common
injury following anterior dislocation of the
glenohumeral joint.
It is a detachment of the anteroinferior
labrum (with or without labral tears) from
the glenoid with a tear of the anterior
scapular periosteum
The Bankart lesion may or may not be
associated with a fracture of the
anteroinferior glenoid.
Bankart lesions
A, T1 fat-suppressed axial shoulder MR arthrogram. The anteroinferior labrum is detached from the
glenoid (arrowhead) and is irregular in shape and high signal from tears. There is no linear
periosteum seen attached to the labrum because it has been torn. The flat posterolateral humerus in
the lower portion of the joint is normal and not from a Hill-Sachs impaction fracture. B, T1 fatsuppressed axial shoulder MR arthrogram (different patient than in A). The anteroinferior labrum is
absent from its normal position adjacent to the glenoid; it has been completely detached and torn free
of the scapular periosteum, coming to rest in the medial aspect of the joint (open arrow).
ALPSA [anterior
labroligamentous periosteal
sleeve avulsion]
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Variant of Bankart.
Periosteum stripped
from scapula, not
torn.
Potential of healing
if reduced
GLAD (Gleno-labral articular
disruption) lesion
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GLAD refers to a nondisplaced anteroinferior labral
tear with an associated chondral injury
This lesion results more from an impaction type of
injury, rather than a shearing injury, as occurs with
Bankart lesions.
The labrum remains attached to the anterior
scapular periosteum, distinguishing this from a
Bankart lesion, which has a torn periosteum.
On MR arthrography, contrast material extends into
the cartilaginous defect.
These patients complain of pain rather than
instability.
Anterior labral lesions
SLAP (Superior Labrum Anterior to Posterior) lesions
SLAP
SLAP
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The inferior glenohumeral ligament is the ligament most
frequently affected with instability.
It may be affected at its labral or its humeral attachment.
Avulsion of the inferior glenohumeral ligament from the
humerus, called a HAGL lesion (humeral avulsion of the
glenohumeral ligament), may result from shoulder dislocation.
It often is associated with a tear of the subscapularis tendon.
HAGL lesions can be identified on axial, coronal, or sagittal
MRIs
The inferior glenohumeral ligament may show high signal
intensity on T2 images, and may show morphologic disruption
at its insertion on the anatomic neck of the humerus and
wavy contours of the residual ligament, and the ligament may
be displaced inferiorly.
The diagnosis also can be inferred on MR arthrography when
extravasation of contrast material from the joint occurs in the
region of the ligament insertion on the humerus.
HAGL
A, T1 fat-suppressed coronal oblique shoulder MR arthrogram. The anterior limb of the inferior
glenohumeral ligament (arrowhead) is detached from the humerus (arrow) in this patient with a
previous anterior dislocation. There also is a bucket-handle superior labral anterior and posterior
(SLAP) tear of the superior labrum. B, T1 fat-suppressed sagittal oblique shoulder MR arthrogram
(different patient than in A). The anterior limb of the inferior glenohumeral ligament (open arrow) is
avulsed from its humeral attachment, is thickened, and is drooping inferiorly (compare with normal
posteroinferior glenohumeral ligament [arrowhead]). The patient had several prior dislocations.
Indirect MR arhtrogram
Complete tear of supraspinatus
Anterior glenoid labrum tear
Acronyms and Eponyms
Related to the Shoulder
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ALPSA: Anterior labroligamentous periosteal sleeve avulsion. A variation of the Bankart
lesion with injury to the anteroinferior labrum, but the anterior scapular periosteum is
intact.
Bankart lesion: Tear of the anteroinferior glenoid labrum with torn anterior scapular
periosteum. May have an associated fracture of the anteroinferior glenoid rim.
Bennett lesion: Mineralization of the posterior band of the inferior glenohumeral ligament
and posterior capsule from chronic traction forces.
HAGL lesion: Humeral avulsion of the glenohumeral ligament occurs from shoulder
dislocation with avulsion of the inferior glenohumeral ligament from the anatomic neck of
the humerus.
BHAGL lesion: Bony HAGL lesion.
Buford complex: Congenital absence of the anterosuperior glenoid labrum associated
with a thickened middle glenohumeral ligament.
GLAD lesion: Glenolabral articular disruption is a tear of the anteroinferior labrum with a
glenoid chondral defect.
Hill-Sachs lesion: Impaction fracture of the posterolateral aspect of the humeral head
from anterior shoulder dislocation.
SLAP lesion: Superior labrum tear propagating anterior and posterior to the biceps
anchor.
DYN: Drives you nuts.
References
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Jacobson et al. Aids to Successful Shoulder Arthrography
Performed with a Fluoroscopically Guided Anterior Approach.
Radiographics. 2003; 23:373–379
Angelica et al. Arthrography of the shoulder: A modified
ultrasound guided technique of joint injection at the rotator
interval European Journal of Radiology. 2009 January.
Beltran et al. MR Arthrography of the Shoulder: Variants and
Pitfalls. Radiographics. 1997; 17:1403-14 12
De Maeseneer et al. CT and MR Arthrography of the Normal and
Pathologic Anterosuperior Labrum and Labral-Bicipital Complex.
Radiographics. 2000; 20:S67–S81
Helms, Major, Anderson. Muskuloskletal MRI. 2nd ed. Chapter 10
Stoller D. MRI in orthopaedics and sports medicine. Volume II.
Chapter 8.
Tuite et al. Rotator cuff injury MRI. Medscape Reference URL:
http://emedicine.medscape.com/article/401714-overview
Thank you