W9 Shoulder methodology

Question 1

RF coils?

Answer 1

Shoulder phased array or surface 5’ ring.

Question 2

Positioning ?

Answer 2

Supine head first, affected shoulder in isocenter, humerus horizontal, coil cover humeral head, surface coil parallel to z-axis. Oblique pt to affected side to flatten shoulder (scapula flat on table) to avoid high degrees of obliquity.

Question 3

Landmarking ?

Answer 3

Through shoulder joint.

Question 4

Staple sequences?

Answer 4

T2 FS, PD, PD FS

Question 5

Planes, weighting, seq?

Answer 5

Routine
Loc 
Ax         T1, T1 FS (3D), T2 FS, T2* FS (3D), PD, PD FS
Obl Cor T1, T2 FS, PD, PD FS
Obl Sag T1, T2 FS, PD, PD FS

Question 6

Arthrogram protocol?

Answer 6

All 3 planes T1 (3D), T2 FS, PD, PD FS

Question 7

Planning ax? Phase dir?

Answer 7

Ax: AC joint to glenoid SI, bicipital groove to distal supraspinatus RL. Phase AP + sat band over chest medially.

Question 8

planning obl cor what to include? Direction? Phase?

Answer 8

Obl Cor: infra to supra AP, acromion to subscap (~1 cm below glenoid) SI, deltoid to distal third of supra RL. Parallel to supra tendon/ perpendicular to joint space. Phase RL + sat band over chest, or phase SI.

Question 9

planning obl sag what to include? Direction? Phase?

Answer 9

Obl Sag: glenoid to bicipital groove RL, joint capsule to acromion SI. Perpendicular to supra tendon or parallel to joint space. Phase AP.

Question 10

fov?

Answer 10

14-16 cm

Question 11

slice thickness/ gap

Answer 11

3-4 mm skip 0-0.5

Question 12

matrix

Answer 12

med to fine

Question 13

rBW

Answer 13

med to low

Question 14

NEX

Answer 14

2 or more

Question 15

IO (3)

Answer 15

OS, FC freq or slice, sat band over chest medially.

Question 16

Indications

Answer 16

shoulder pain, impingement, rotator cuff tear, recurrent dislocation, Hill Sachs, Bankart, Bennet, SLAP lesion.

Question 17

Is gad routine? what is it for?

Answer 17

no. cyst vs solid, inflammation vs infection from abscesses, arthrography (intra-articular), perfusion (osteoid osteoma)

Question 18

intra-articular use of gad to diagnose rotator cuff tears, glenoid labral disruption, bicipital tendon and chondral defects= ?

Answer 18

Athrography

Question 19

how is arthrogram performed? (ie. gad dilution, injection site, guidance)

Answer 19

Diluted gad (gad in saline 1:100) injected to joint-capsule under fluoroscopic guidance, then MR

Question 20

IV injection of gad by body weight (no fluoro, non-invasive)= ? when is it used?

Answer 20

indirect arthography.
o When direct not possible, not as common/effective
o Exercise to increase gad circulation
o Inflamed tissue enhance.

Question 21

Aber (abduction external rotation shoulder arthrography)= ?

Answer 21

o Obl sag – angle to long axis of humerus

o Obl cor can also be requested

Question 22

• For high degrees of obliquity, some systems swap phase and freq - aliasing, some alter orientation. what to do?

Answer 22

o Oblique pt to affected side to flatten shoulder.

Question 23

what is magic angle?

Answer 23

tendons brighter than normal due to short TE and tendon 55° to Bo.

Question 24

what does magic angle mimic?

Answer 24

o Normal tendons and ligaments are hypointense – high signal= tears
o Mimics pathology, reposition joint and inc TE (maintain weighting)