This document provides an overview of MRI techniques for evaluating the shoulder joint and common shoulder pathologies. It begins with normal shoulder anatomy as seen on MRI and descriptions of impingement syndrome, rotator cuff tears, labral tears, instability, biceps tendon injuries, and other conditions. For each pathology, the document describes MRI appearance and features that should be included in reports. In summary, the document is a guide for radiologists to understand MRI of the shoulder and identify and characterize various shoulder injuries and diseases.

1. MRI SHOULDER JOINT AND
COMMON PATHOLOGIES
Dr. Gobardhan Thapa
MD Radiodiagnosis
NAMS, Bir hospital

2. Presentation outlines
 Normal anatomy
 MRI techniques
 Impingement and Rotator cuff disease
 Glenohumeral instability/dislocations
 Bicipital tendon pathologies
 Calcium deposition disease
 Adhesive capsulitis
 Infection and inflammatory conditions
 neoplasm

3. Anatomy

5. MRI protocols

6. MRI anatomy
Axial T1-weighted sections of shoulder (normal anatomy)

7. Fig. A to C: (anterior to posterior) Oblique coronal T1
weighted sections (normal anatomy).

8. Fig. A to C: Oblique sagittal T1 (A, B – medial to lateral) and
T2- weighted sections (C) (normal anatomy).
The intra-articular course of biceps tendon can be seen
coursing through the rotator cuff interval.

9. SHOULDER IMPINGEMENT SYNDROME
• Encroachment of the rotator
cuff and associated soft
tissues between the humeral
head and overlying
coracoacromial arch (CCA).
• Abnormalities involving one
or more of the components
of CCA results in narrowing of
the acromiohumeral distance.

10. Classified as:
• Extrinsic factors:
–Due to mechanical impingement by
surrounding structures:
• Primary extrinsic
• Secondary extrinsic
• Intrinsic factors.

11. Primary Extrinsic Impingement
Due to the abnormalities of the CCA -
Etiologies:
–Subacromial spur.
–Hypertrophic changes in AC joint.
–Unstable os acromial (failure to fuse by 25
years).
–Subacromial subdeltoid bursitis.
–Thickening of the coracoacromial ligament.
–Laterally down-sloping acromian process
(Type 3).

12. • Anterior acromion is straight
in Type I, curved in Type II
and anteriorly hooked in Type
III morphology.
• Type II - commonest and
• Type III - most commonly
associated with rotator cuff
pathology.
– Anterior part of SST is most
commonly affected in
subacromial type impingement
alone or along with other
tendons in 95 per cent cases.
• Type IV: convex inferiorly (no
significance seen)

13. Fig. SST tendinopathy Proton (A) and T2 TSE (B) coronal sections
show increased signal within the SST (A, long arrow), however
T2WI (B) shows less pronounced signal changes in the tendon.
Partial retraction at the insertion site with cyst formation is
also noted (short arrow).

14. Fig. Proton (A) and T2 TSE (B) coronal sections show impingement of the SST at
the undersurface of AC joint which shows gross arthropathic hypertrophy
(long arrow) leading to intrasubstance increased signal (tear) at the
musculotendinous junction on both the images (short arrow).

15. Os acromiale:
• 3 ossification centers meta-
acromion (base)
– origin of posterior portion of deltoid
• meso-acromion (mid)
– origin of middle deltoid
• pre-acromion (tip)
– origin of anterior deltoid fibers and
coracoacromial ligament
Normal AC Joint
Double acromian sign

16. Secondary Extrinsic Impingement
• Abnormality lies in the stability of the
glenohumeral joint in the setting of a
normal CCA.
• In young athletes involved in sports
demanding overhead arm movements.
• Defect of static stabilisers (glenohumeral
ligaments) => overload on secondary
stabilisers (cuff structures) => reduced
acromiohumeral gap.

17. Internal Impingement
• Due to degenerative changes in the
substance of rotator cuff with increasing
age.
• Throwing with arm in abduction and
maximal external rotation - > contact
between undersurface of rotator cuff and
glenoid rim.
• Supraspinatus hypertrophy or an
abnormality of the greater tuberosity may
also be contributory factors.

18. • Impingement is a process of progressive wear
and tear.
MRI
• often equivocal in early stages.
• injured tendon may appear thickened due to
mucoid degeneration.

19. Impingement syndrome classification:
(Neer and colleagues)
• Stage I:
– Edema and hemorrhage in distal supraspinatus
tendon and usually reversible with conservative
treatment.
• Stage II:
– Associated with tendinitis; and thickening and fibrosis
of SASDB.
• Stage III:
– Parital or full thickness tear of rotator cuff or biceps
tendon, ±osseous changes (osteophytes and
degenerative changes in greater tuberosity).

20. ROTATOR CUFF TENDINOPATHY /TEARS
• Rotator cuff disease - most
common causes of shoulder pain
and indication for MRI evaluation
of shoulder.
• Acute and chronic trauma, sports,
overuse, aging, collagen vascular
and metabolic diseases are also
associated with rotator cuff
tendinopathy and tears.
• Vascular insufficiency =>
degeneration in critical zone may
also plays a role in rotator cuff
tears (RCT).

21. Fig. Partial tear of SST. T2 TSE coronal section shows a
small articular surface tear as a focus of bright signal
area along the undersurface of the SST (arrow).

22. • Complete rotator cuff tears occur at sites
of previous tendinopathy.
• classified as
–small (less than 1 cm or involvement of one
tendon only),
–medium (1 to 3 cm or involvement of two
tendons) and
–massive (more than 3 to 5 cm or
involvement of three or more tendons).

23. Fig. A T1-weighted fat-saturated coronal oblique MR arthrographic
image shows an articular-side partial tear (arrow). B, T1-weighted
sagittal oblique MR arthrographic image. On the articular side of the
supraspinatus tendon is a defect filled with gadolinium-based
contrast (arrow), with an intact bursal surface. No contrast is present
in the subdeltoid bursa

24. • Massive tears of
the rotator cuff
may also involve
the subscapularis
and biceps with
or without
dislocation.
Fig. Oblique sagittal T2 TSE section
through the rotator cuff shows a
massive tear involving SCT, SST as well
as the IST (from anterior to posterior -
arrows) seen as increased T2 signal
replacing normal low signal of the
tendons.

25. Fig. T2 TSE coronal section: Full thickness tear of SST
without tendon retraction (short arrow). There is fluid in
the SASDB and axillary recess. AC joint osteophyte is
noted (long arrow).

26. Secondary signs of rotator cuff tear –
MRI
– Fatty atrophy of muscle belly in complete tears as
T1 hyperintensity and loss of volume.
– Humeral head apposed to the acromion in chronic
cases.
– Tendons may be completely nonvisualised due to
musculotendinous retraction in complete tears.
– Tendon retraction, loss of peribursal/ subdeltoid
fat plane and fluid in the subdeltoid subacromial
bursa - in 92 % patients with complete rotator cuff
tear.

27. Fig. T1 SE coronal section: Chronic rotator cuff tear
with SST retraction, atrophy of the muscle and fatty
changes seen as T1 hyperintensity (arrow).

28. • secondary signs of
cuff tendinopathy:
– Marrow signal
changes and cyst
formation in the
greater tuberosity
on fat suppressed
T2 WI
– osseous changes
like AC joint
osteophytosis and
subacromial spurs.
Fig. Supraspinatus tendinopathy. A, PD-weighted
coronal oblique image. The area of increased signal in the
distal supraspinatus tendon shows thickening indicating an
area of tendinopathy. B, T2-weighted coronal oblique image
with fat saturation. The focus of increased signal is more
pronounced, thus excluding the magic-angle effect. There is
adjacent subchondral edema in the humeral head.
Acromioclavicular joint degeneration is noted.

29. Rotator cuff injuries: Reporting checklist
1. Dimension of a full thickness tear.
2. Depth of partial thickness tear.
3. Tear shape: crescentic, U or L type.
4. Tendon retraction
5. Tear extension.

30. Calcific tendinitis
• degenerative condition - deposition of
hydroxyapatite crystals within the tendon.
• Mostly supraspinatus, followed by
infraspinatus, teres minor and subscapularis
tendon.
• Middle aged women – dominant shoulder.

31. • Plain radiographs:
cloudy ill-defined
deposits
• Readily apparent on
CT. MRI rarely
needed.
• Tendon rupture,
bursitis or adhesive
periarthritis and can
be extremely painful.
Fig. Calcific tendinitis – MRI T2 coronal
and plain xray

32. Joint Instability/dislocation
• dynamic stabilisers - rotator cuff.
• static stabilisers - glenoid labrum,
joint capsule, GHL and periarticular
soft tissue.
–Pathology of any of these structures
can predispose to instability.

33. • Anterior and posterior bands -
thickenings of anterior and posterior
margins of IGHL, which prevent anterior
and posterior dislocation respectively.
• Most important static stabiliser of
shoulder => anterior band of inferior
GHL, which prevents anterior
dislocation.

34. • Anterior instability:
–Most common in subcoracoid location.
– Subglenoid, subclavicular, intrathoracic (very rare).
–Shoulder will be in abduction and
external rotation.
• MR findings:
–Labral and glenoid rim abnormalities.
–Capsular stripping
–Deformities of humeral head.

35. • Bankart lesion (cartilaginous Bankart) -
anteroinferior labral tear with rupture of
scapular periosteum,
• Bankart fracture (bony Bankart) -
fracture of anterior glenoid rim
• Hill Sach’s lesion - impaction fracture in
superior posterolateral aspect of humeral
head.

36. • Hill Sach’s lesion:
– compression defect in the
normally round
posterolateral humeral head
at/superior to level of
coracoid process on axial
images (as opposed to
normal flattening of head
below it).
– marrow oedema in recent
injuries.
– predispose to recurrent
dislocation with minimal
trauma and may affect
surgical planning.
Fig. T1 SE axial section: There is a wedge
shaped defect at the posterosuperior
aspect of the humeral head
representing Hill Sach’s lesion (arrows)
due to anterior dislocation of shoulder.

37. Labral Tears
• labrum shape: variable
(triangular, rounded, blunted,
crescent shaped).
• Most common: triangular
anteriorly and rounded or
triangular posteriorly.
• Few horizontal notches and
vertical clefts along anterior
aspect of labrum - normal.
• seen posteriorly - considered
tears.
Fig. Gradient-echo axial section
shows normal anterior and posterior
triangular labra undercut by a bright
appearing articular cartilage
(arrows).

38. • Labral tear -
– complete absence of a
portion of labrum,
– displacement of labrum
from glenoid rim or
– linear area of increased
signal intensity within the
labrum on T2WI.
Fig. T2 TSE axial section at the inferior
head level: Bankart lesion is seen as a
fragmented anterior inferior labrum with
a defect at its base reaching the articular
surface (arrows).The glenoid rim shows
oedema as increased signal.

39. MR arthrography - technique of choice for
diagnosing labral pathology.
• Contrast entering the labrum or tracking
beneath the labrum to the external surface of
joint - suggests tear.
• Positioning the arm in abduction and external
rotation (ABER) => puts tension on and
improves evaluation of anterior band of IGHL
and anterior inferior labrum => increase the
sensitivity of MR arthrography.

40. Fig. MR arthrogram shows a detached labrum with
contrast outlining its base (white arrow). Also note the
medially dislocated biceps tendon from its groove and
lying anterior to the SCT (black arrow).

41. SLAP (superior labrum,
anterior to posterior) lesions
–important cause of
traumatic
instability.
–typically seen in
young people
involved in sports
activity requiring
overhead
movement of
humeral head, like
bowlers.
Fig. SLAP (superior labrum, anterior and posterior)
lesion as shown on T2-weighted fat-saturated
coronal oblique MR arthrogram. Fluid (arrow) fills
the cleft in the labrum and turns laterally, away
from the glenoid. There is also tendinopathy and
partial-thickness tear of the bursal surface of the
supraspinatus tendon (arrowheads).

42. SLAP lesion
–Believed to be caused by repetitive
contact of humeral head with
posterosuperior labrum.
–Consequently labrum becomes weak
and tears away.
–Gradually tear progresses from
posterior to anterior direction.

43. Capsular tear
Variations in anterior capsule insertion
–capsule inserts near the labrum, just medial
to the labrum or attached greater than 1 cm
from the labral margin.
Large capacious anterior
pouch/subscapularis bursa - frequent
secondary finding in patients with
recurrent anterior subluxation.

44. Fig. T2 TSE axial section shows a Subscapularis tendon
tear. The retracted tendon fibres (black arrow) and
marrow oedema at the lesser tuberosity (arrow head)
can be seen. A redundant posterior capsule indicates
shoulder instability (long arrow).

45. Posterior instability (5%)
• much less common than anterior (2-4%).
• anterior direct blow on shoulder or seizures.
• Imaging findings:
– subscapularis tears along with teres minor injury,
posterior labral and capsular tear and
anteromedially located reverse Hill Sach’s lesion
(trough sign).

46. Fig. Turbo inversion recovery axial sections show classical anteromedial bony defect
of reverse Hill Sach’s lesion due to posterior dislocation (A-arrows) and associated
teres minor tendon tear (B-arrow). The posterior labrum is infolded and
heterogenous in signal.

47. Fig. Posterior labral tear as shown on T1-weighted fat-saturated axial MR
arthrogram. There is dissection of gadolinium-based contrast between the
labral substance and the underlying glenoid cartilage (arrow). An associated
trough fracture of the anterior humeral head is present (arrowhead).

48. Pitfalls:
Anatomic variants mimicking labral tear
Sublabral recess (30% patients)
MR arthrography:
– recess seen anterior to biceps
tendon attachment while SLAP
tears usually seen at or posterior
to it.
– Contrast in sublabral recess seen
as a thin line with smooth
margins that runs along the
glenoid.
– Contrast in a tear has irregular
margins, globular shape and is
seen to enter into labral
substance.
Fig. Sublabral recess. T1-weighted
fat-saturated coronal oblique MR
arthrogram. A smooth-bordered
collection of gadolinium (arrow)
parallels the cortex of the
superior glenoid.

49. • Sublabral hole (17% normal people)
– present at 2 O’clock position in pear shaped glenoid
cavities.
• Buford complex
– Association of thick MGHL and an absent
anterosuperior labrum -
– also a normal variant.
• The bright signal of hyaline cartilage between
glenoid rim and labrum and the gap between
MGHL and anterior glenoid can mimic tears of
labrum.

50. Fig. Buford complex. There is absence of the anterosuperior glenoid labrum (large
arrow), with a cordlike, thickened middle glenohumeral ligament (small arrow), in
keeping with a Buford complex. This can be distinguished from a cartilaginous Bankart
lesion by following the thickened middle glenohumeral ligament toward the anterior
capsule.

51. ADHESIVE CAPSULITIS
(frozen shoulder)
– clinical syndrome of pain and restricted joint
movement
– Most commonly in 40 to 60 years old females.
– associated with trauma, osteoarthritis or rheumatic
disorders.

52. • Joint capsule and synovial thickening of more
than 4 mm at the level of axillary recess - useful
MR criterion to diagnose this condition.
• Post-contrast enhancement of the rotator cuff
interval or axillary recess may be present.
• MR arthrography - decreased joint volume (less
than 10cc), decreased fluid volume in biceps
tendon sheath and axillary recess, corrugations
of capsule with thickening and rotator interval
abnormality.

53. Fig. T2 TSE coronal section—The axillary pouch
(arrows) shows an abnormally thick wall
(more than 4 mm) indicative of adhesive
capsulitis in a patient after trauma.
Fig. Adhesive capsulitis. T1-weighted fat-saturated
coronal MR arthrogram demonstrates thickening
of the inferior glenohumeral ligament (arrow).
There is also lack of capsular distention with
intraarticular contrast, in keeping with adhesive
capsulitis.

54. ABNORMALITIES OF BICEPS TENDON
Bicipital
Tendinopathy/Rupture
• Middle aged or older patients
with rotator cuff disease
• due to impingement of biceps
tendon
• beneath coracoacrominal
ligament and anterior
acromian.

55. • This impingement may cause
tendinopathy (or tenosynovitis) with
flattening and thinning of tendon => lead
to complete rupture of the tendon.
• Also occur in patients with glenohumeral
instability and attrition at the groove.

56. • Early bicipital tendinopathy often goes
undetected on MR studies.
• MRI
– increased signal intensity within the abnormal
tendon.
– Morphologic abnormalities such as fraying,
flattening and absence of tendon.
– Disproportionate amount of fluid in bicipital
tendon sheath as compared to the joint fluid may
suggest bicipital abnormality, i.e. tenosynovitis.

57. Fig. Normal Biceps tendon pulley. A, Sagittal
T1-weighted image of the rotator interval
demonstrating the coracohumeral ligament
(arrow) and the superior glenohumeral
ligament fibers blending to envelop the
intraarticular biceps tendon (arrowhead). B,
Sagittal T1-weighted MR arthrogram with fat
saturation showing an intact capsule, with the
pulley surrounding the intraarticular biceps
tendon (arrow).
Fig. Bicipital tendinopathy. A, Gradient
echo axial image at the level of the inferior
labrum shows distention of the biceps
tendon sheath, with fluid and thickening
of the tendon (asterisk), in keeping with
tendinopathy. The tendon is intact. B, T2-
weighted sagittal oblique image. Fluid
within the biceps tendon sheath can
extend along the tendon (arrowheads).

58. Bicipital Tendon Dislocations
• Usually occurs with the chronic
rotator cuff tears that have extended
to involve the subscapularis tendons.
• symptoms usually masked by those
of rotator cuff tears.

59. • Some fibres of subscapularis along with deep
fibres of coracohumeral and the superior GHL
complex forms the pulley for biceps tendon
and the bicipital groove is hooded by
transverse humeral ligament.
• all three structures disrupted - tendons of long
head of biceps dislocates medially posterior to
subscapularis tendon into the joint.

60. • Axial MR images
– bicipital groove is
empty with
medially dislocated
tendon in cases of
biceps dislocations. Fat suppressed T2TSE axial section: biceps
tendon is seen dislocated medially (arrow)
with an empty bicipital groove.

61. Congenital absence of biceps tendon
• Rare anatomic variant (confused
with complete tear).
• Flat intertubercular groove.
• Fibrous thickening of undersurface of
distal supraspinatus tendon.

62. NERVE ENTRAPMENT SYNDROMES
A. Quadrilateral Space Compression Syndrome
• Quadrilateral space is
bounded by teres minor
superiorly, teres major
inferiorly, shaft of humerus
laterally and long head of
biceps medially.
• Axillary nerve and posterior
humeral circumflex artery
and vein pass though it.

63. • Pain and paraesthesia in axillary nerve distribution
and muscle atrophy of teres minor and major
muscles.
• MR imaging
– does not show actual entrapment
– but excludes other causes of shoulder pain and
only shows atrophy of teres minor with major
muscle.
• MR angiography or DSA - occlusion of posterior
circumflex humeral artery.

64. B. Suprascapular Nerve Entrapment
• Suprascapular nerve passes through supraspinatus
notch to enter supraspinatus fossa beneath
supraspinatus muscles. Further posteriorly it passes
though spinoglenoid notch to enter into the
intraspinatus fossa.
• supplies both supraspinatus as well as infraspinatus
muscle.
• Compression at the level of suprascapular notch - in
atrophy of both muscles and
• compression at the level of spinoglenoid notch -
atrophy of infraspinatus muscle only.

65. • Etiologies: neoplasm, haematoma or most
commonly ganglion cyst.
• MR - fatty replacement of involved muscle and
soft tissue lesion responsible for compression.
– Ganglion cysts are either associated with labral
tears or typically arise from a posterior capsular
defect and present at spino-glenoid notch.
– Isointense to muscle on T1WI and hyperintense
on T2WI.

66. Fig. Spinoglenoid notch ganglion. A, Axial gradient
echo image at the level of the superior labrum
reveals a fluid-filled structure in the spinoglenoid
notch ganglion (asterisk). B, Coronal T2-weighted
image reveals that the cyst (asterisk) has occupied
the spinoglenoid notch and displaced the belly of
the adjacent supraspinatus superiorly. No
associated muscle atrophy is present.

67. C. Acute brachial neuritis/
Parsonage-Turner syndrome
• Sudden onset intense burning
shoulder pain and muscle weakness
• Most commonly supraspinatus and
infraspinatus muscle involved.
• in young male; Self limiting.

68. MRI:
–Increased T2 signal
in involved muscles.
–Later: muscle
wasting without
fatty infiltration.
–MRI: exclusion of
other causes in
shoulder pain and
dysfunction.
Fig. Parsonage-Turner syndrome. Sagittal
T2-weighted fat-saturated image of the
shoulder reveals edema in the
supraspinatus and infraspinatus muscles,
suggestive of brachial neuritis.

69. INFECTIONS AND INFLAMMATORY
DISEASES
SEPTIC ARTHRITIS
• a clinical diagnosis relying on physical
and laboratory parameters and
microbiologic assessment of joint
aspirate.
• older age group (average 65 years).
• Either haematogenous or local source.

70. • Conventional radiographs, may show
associated osteoarthritis, osteomyelitis or
serve as a baseline study to monitor disease
progression or response to treatment -
insensitive to pick up early marrow or soft
tissue changes.
• MR demonstrates these well along with bone
changes, however its specificity is low.

71. • Fat saturated T2WI and post contrast T1WI -
Inflammation of synovial lining and joint effusion,
the earliest pathologic changes and associated
bone marrow oedema.
• Osteomyelitis, bone destruction and joint
ankylosis are features of chronic septic arthritis.
• Rotator cuff tears can also be seen in subacute
and chronic disease.

72. T2 TSE fat suppressed coronal section (A) reveals marked bone
marrow and periarticular soft tissue oedema and synovial
thickening in a case of septic arthritis. T1 SE post-contrast
(B): There is enhancement of the synovium and the periarticular
tissue (arrows).

73. • MR can not distinguish septic from non-septic
arthritis.
• Combination of bone erosions with marrow
oedema favours infectious aetiology.
• Moreover, differentiation of reactive marrow
changes from osteomyelitis is difficult on MR
as both show bone marrow oedema and
enhancement.
• Overt changes on T1WI favours latter.

74. RHEUMATOID ARTHRITIS
• Chronic inflammatory joint disease
involving synovial lining of joints.
• involvement of articular cartilage,
bone at joint margins and peri-
articular soft tissue.
• Shoulder joint becomes involved
later in the disease process.

75. • Proliferative synovitis involves
glenohumeral joint, AC joint and bursae
around shoulder.
• Rotator cuff also becomes involved as
disease progresses.

76. Imaging
MRI –
–detecting early changes of RA including
synovitis, joint effusion and marginal
erosions.
–Marginal erosions - low-signal areas on
T1WI and variable signal intensity on
T2WI.

77. Fig. Rheumatoid arthritis. A, T2-weighted fat-saturated coronal oblique
image. There is uniform loss of articular cartilage. Multiple T2-weighted
high-signal-intensity foci are noted in the subchondral bone, likely cysts.
These findings may also be seen in late-stage osteoarthritis. B, Axial
gradient echo image in a patient with RA confirming uniform loss of
articular cartilage and subchondral cysts. There is a focal erosion on the
posterior aspect of the humeral head.

78. • Rotator cuff tears - commonly seen in RA
due to destructive synovitis near greater
tuberosity.
• Synovial cysts, subacromial and sub-
deltoid bursitis and arthritic
involvement of AC joint.

79. AVASCULAR NECROSIS
• Due to trauma, steroid use, sickle cell anaemia and alcoholism.
• Differentiated from osteoarthritis by signal abnormality
confined to the humeral head and sparing of glenoid.

80. • MR may show focal subarticular
dark signal, a dark line
encircling normal marrow or a
double line sign early on and
fragmentation and collapse of
head later.
• Metadiaphyseal lesions may
show classical serpiginous low
intensity line surrounding high
intensity centre (in chronic
infarcts) and high intensity rim
in more acute infarcts.
Fig. AVN left shoulder. Coronal
oblique T2 MR image shows the
subarticular lesion in the humeral
head.

81. NEOPLASMS
Role of MRI
–imaging modality of choice for
characterising and staging both primary and
secondary musculoskeletal neoplasms and
tumour like lesions.
–Shows joint involvement, soft tissue and
osseous components, involvement of
neurovascular structures as well as helps in
tissue characterisation.

82. • T1WI (for marrow involvement), T2WI
(for soft tissue extension), STIR and post-
gadolinium fat suppressed T1WI
diagnose and stage tumours well.
• Metastatic disease:
–commonest malignant tumour around
shoulder followed by myeloma,
osteosarcoma, chondrosarcoma and Ewing’s
sarcoma.

83. • Benign lesions:
–osteochondroma, chondroma,
chondroblastoma and giant cell tumour.
• Soft tissue lesions:
–lipoma and extra- abdominal desmoid -
unique predilection for soft tissues around
the shoulder.

84. Fig. 50-year-old woman with desmoid tumor. A, T1-weighted axial image shows mass
(arrowheads) of low signal intensity, which is nonspecific. B, T2-weighted image shows
that most of mass (arrowheads) remains low in signal intensity, characteristic of fibrous
tumor (in this patient, desmoid tumor). Bands of low signal intensity on both T1-
weighted (A) and T2-weighted (B) images correspond to areas of dense collagen; areas
of high signal intensity on T2-weighted image (B) correspond to hypercellular areas, and
thus high water content, in tumor.
C, T1-weighted axial image with fat saturation obtained after administration of
gadolinium shows that mass (arrowheads) enhances avidly.

85. Conclusions
• MRI - extremely useful imaging tool in
identifying pathologic changes in the shoulder.
• Several lesions providing diagnostic challenges
=> needs close clinical correlation.
• Recent advances:
– more lesion specific joint positioning, e.g ABER
positioning;
– MR arthrogram.

86. References
• Diagnostic Radiology, Berry 3/e.
• CT and MRI of the whole body, Haaga, 6/e.
• Various internet sources.

87. Thank you