Resources/Protocols
Routine shoulder
The most mobile joint, and the least stable. You are hunting rotator-cuff and labral tears — and success is defined by two things: getting the shoulder into the magnet's isocentre, and planning the oblique views along the tendon.
When this study is used
- Rotator-cuff tear, impingement or shoulder pain.
- Suspected labral tear or instability after dislocation.
- Assessment of muscle atrophy in chronic cuff disease.
Patient & coil positioning
- Head-first supine; shift the body 2–3 inches toward the unaffected side so the examined shoulder sits at the magnet's isocentre — an off-centre shoulder fails fat suppression.
- Arm neutral, thumb up (palm to thigh), small wedge at the elbow; internal rotation curves the supraspinatus and hides tears.
- Depress the shoulder ('relax it toward your feet, don't shrug'); strap across the chest and sandbag the opposite side against roll.
- Dedicated shoulder array coil centred over the palpated acromion.
Localizer
Three-plane localizer. Axial from the AC joint to the axillary pouch; coronal from the scapular body to the deltoid. The obliques are then planned off the axial.
Sequence planning
Each sequence below lists how the slice group is positioned — the reference line it follows, its coverage, and why it earns its place in the protocol. Plan against the localizer, not by eye.
Oblique coronal PD fat-sat
Oblique coronalPlanning — Parallel to the supraspinatus tendon (or the flat scapular body) on the axial. Coracoid to scapular spine — this elongates the tendon from insertion to muscle belly.
Why — The money view for rotator-cuff tears; fluid cutting the black tendon.
Oblique sagittal PD/T2 fat-sat
Oblique sagittalPlanning — Perpendicular to the glenoid on the axial. Deltoid to scapular notch — the 'Y-view' of coracoid, acromion and scapula.
Why — Acromion shape (impingement) and the cuff footprint.
Axial PD fat-sat
AxialPlanning — Perpendicular to the glenoid face on the coronal; above the AC joint to below the axillary pouch.
Why — Anterior and posterior labrum (Bankart), biceps tendon in the groove.
Oblique coronal T1
Oblique coronalPlanning — Same plane as the PD.
Why — Muscle atrophy (fatty streaks) marking a chronic tear; bone anatomy.
Representative parameters
Ranges, not commandments — field strength, coil and vendor move the numbers. What must not move is understanding why each sits where it does.
| Sequence | Field | Matrix / FOV | Notes |
|---|---|---|---|
| PD fat-sat | 1.5–3 T | 320–384 / 14–16 cm | Cuff and labrum |
| T2 fat-sat | 1.5–3 T | 320 / 14–16 cm | Confirms tears (fluid) |
| T1 | 1.5–3 T | 320 / 14–16 cm | Atrophy, anatomy |
| T1 fat-sat (arthrogram) | 1.5–3 T | 320 / 14 cm | If intra-articular contrast given |
Artifacts & how to fix them
| Artifact | Typical cause | Mitigation |
|---|---|---|
| Failed fat-sat | Shoulder off isocentre | Shift the body toward the unaffected side; re-shim |
| Wrap / ghost arm | Chest wall or opposite arm in phase FOV | Swap phase to AP; oversampling; oblique sat band |
| Magic angle | Tendon at 55° looks torn on PD | Compare with T2 (long TE) — artefact fades if normal |
| Breathing motion | Chest-wall respiration | Tighten chest strap; shallow belly-breathing; bellows |
What am I looking at?
You are not reporting the study, but recognising pathology helps you keep it in the field of view and know when to add a sequence or contrast. How the common findings read on the console:
| Finding | Sequence to check | How it reads |
|---|---|---|
| Rotator-cuff tear | Oblique coronal PD FS | Bright fluid cutting the black tendon; retraction = full rupture |
| Labral tear (Bankart) | Axial PD FS | The black glenoid triangle detached or missing |
| Hill–Sachs lesion | Axial (top slices) | Wedge dent in the posterolateral humeral head |
| Chronic tear | Oblique coronal T1 | Fatty streaks of muscle atrophy |
Review checklist
- Shoulder at isocentre — fat suppression uniform.
- Supraspinatus profiled full-length on the oblique coronal.
- Y-view acromion shape shown on the oblique sagittal.
- Labrum and biceps groove covered on the axial.
Mistakes that cost repeats
- Scanning the shoulder off-centre and losing fat suppression.
- Internal rotation curving the supraspinatus and hiding a tear.
- Calling a magic-angle tendon torn without checking T2.
- Straight (non-oblique) planes foreshortening the cuff.
Common questions
- Why shift the patient toward the opposite side for a shoulder MRI?
- It places the examined shoulder at the magnet's isocentre. A shoulder scanned off-centre suffers field inhomogeneity, so fat suppression fails and the images turn dark and grainy.
- Why is the arm kept thumb-up (neutral) for the cuff?
- Neutral rotation profiles the supraspinatus tendon along its length. Internal rotation (hand on the stomach) curves the tendon, which can hide a tear from view.
- How do you tell a magic-angle artefact from a real cuff tear?
- Compare with the T2 sequence. Magic-angle brightening on PD (tendon at ~55° to the field) disappears at the long TE of T2. If it's bright on PD but dark on T2, it's the artefact, not a tear.
Try it in ScanFlo: Plan the oblique coronal along the supraspinatus, then a straight coronal, and compare how much of the tendon each shows. The oblique lays it out from footprint to muscle; the straight one foreshortens it — which is why the cuff view is always angled.