1. Benoit Hainaux, Eric Lévêque Nathalie Chemla Paris v Clinic FRANCE
SHOULDER HOW I DO IT ?
Benoit Hainaux, Eric Lévêque
Nathalie Chemla
Paris v Clinic
FRANCE
Basics Of MRI:How I Do It AFIIM -ISRA 2015

2. COIL Dedicated phased array Or flex coil type
Closer to B0 center for a better FAT SAT
If the patient has too big shoulders or too big breasts, you won’t be able to put the shoulder at the bottom of the coil and and you will decrease your SNR (you must always choose the coil which is the closer from the part of anatomy you want to study). If you have, new flex type coils maintained with velcro strip can be used also in this case, and allows you further explorations like subclavicular fossa, pectoral muscle or axillary fosea
In a general way, always put the examinated anatomy at the center of B0 for a better magnetic field homogeneity and finally a better image quality. In the shoulder case, move your patient to the opposite side of the table

3. COIL What happens when coil touch the tunnel T2 FAT SAT T2 FAT SAT
Arrows shows a fat sat default, and the circle a phase inconsistency phenomenon

4. PATIENT POSITION Lying on his back, opposite side rotated by 45°
Arm along the body, neutral rotation,
maintained with velcro strip
Arm horizontalized
To have the same position as xray incidense and same anatomic references
Neutral rotation is obtained when elbow bicondylar plane is 45° compared to vertical, arm must be horizontalized so that humeral head and diaphysis are in the same plane
Ask for slow breathing and no big inhalations
Patient mustn’t move legs because arm is fastened to
Protect patient from the inside tunnel to avoid burn hazard

5. SLICES POSITION Coronal plane Sagittal plane Axial plane
“Y” shape of scapula
Coronal plane : parallel to supra spinatus axis, one slice on both sides of humeral head
Sagittal plane : perpendicular to coronal slices, and cover to the “Y” shape of the scapula
Axial plane : from acromioclavicular joint to two slices under the glenohumeral joint

6. CRITERIA OF SUCCESS SST SSM
Supraspinatus tendon in the axis of the supraspinatus muscle in coronal plane
Supraspinatus muscle and in sagittal plane
From acromioclavicular joint and over glenohumeral joint in axial plane

7. MAGIC ANGLE ARTIFACT Appears on tendons, ligaments and cartilages
Collagen fibers are an anisotropic structure
Normally hypo signal
Anisotropic means that water molecule diffuse, in other words move, more easily in the direction of collagen fibers.
Thus, signal intensity is significantly reduced on tendons because water molecular movements are reduced (only one direction).
The normal signal is low signal intensity on all weightings as the Achilles’ tendon for exemple

8. MAGIC ANGLE ARTIFACT If the tendon is 55°oriented compared to B0 axis
Short TE sequences (SE T1 and PD, GE)
It appears enhanced B0
55° B0
55°
This is the magic angle artefact
Supraspinatus tendon appears enhanced on its tilted part
SE PD, TE=50ms

9. MAGIC ANGLE ARTIFACT Others anatomies and weightings… SE T1 TE=7ms
On T1 weighting, supraspinatus is enhanced and is iso signal intensity
Same signal on the PCL

10. MAGIC ANGLE ARTIFACT Others anatomies and weightings SE PD TE=50ms
Fibular longus tendon on the ankle and flexor pollicis longus tendon on the hand are enhanced on this PD and T1 weighted sequence
SE T1 TE=8ms

11. MAGIC ANGLE ARTIFACT To reduce this artifact :
SE PD TE=50ms
To reduce this artifact :
Change orientation of the tendon
Use longer TE
T2 w sequences instead of PD w
SE instead GE
SE T2 TE=80ms
For example if you you want to study flexor pollicis longus tendon, you can turn the hand in a way to align tendon to B0 axis

12. PROPELLER/BLADE/MULTIVANE
Radial sampling method of the k-space
Using rotating blades composed of phase- encoded lines
Motion artefact reduction method
Phase
Without propeller
With propeller
Blades are seen in blue, phased-encoded lines in red
Each blade is composed from 8 to 32 phased encoded lines

13. PROPELLER/BLADE/MULTIVANE
SE, GE, EPI
One blade is acquired in a single shot
Then blade is rotated by a small angle (10-20°)
This process continues till the entire k-space has been collected

14. PROPELLER/BLADE/MULTIVANE
Center of k-space is oversampled
Redundancy of information
Data from each new blade can be compared to the previous one
Data can be corrected
All blades go through center of k-space, compared to normal sampling.
The center contains the highest signal amplitude and contributes most to image contrast. Therefore, SNR and CNR will be high.
Oversampling also provides a redundancy of information, meaning that the data from each new blade can be compared to the previous one for consistency (cohérence). If the patient moves between two blades, data for the second blade can be corrected or discarded, based on how anomalous its central information is

15. PROPELLER/BLADE/MULTIVANE
Example
It is extremely usefull if the patient has voluntary or involuntary motion

16. PROPELLER/BLADE/MULTIVANE
Example
We can see a cancelation of popliteal artery motion artefact

17. PROPELLER/BLADE/MULTIVANE
Example
An other example with arterey motion artifact

18. FSET2 IN THREE ORTHOGONAL PLANS
NO FAT SAT DP
AVOID MAGIC ANGLE
Basics Of MRI:How I Do It AFIIM -ISRA 2015

19. Basics Of MRI:How I Do It AFIIM -ISRA 2015
FSE T1 ANATOMIC SEQUENCES GOOD VISUALISATION OF BONE MARROW ANS MUSCLE TROPHICITY
SUPRASPINATUS
SUPRASPINATUS
INFRASPINATUS
AND TERES MINOR
SUBSCAPULARIS
FSE T1
FSE T1
Basics Of MRI:How I Do It AFIIM -ISRA 2015

20. Basics Of MRI:How I Do It AFIIM -ISRA 2015
MOTION ARTIFACT
FSE T1
FSE T2
GOOD CONTRAST BETWEEN FLUID AND MUSCULOSKELETA
Basics Of MRI:How I Do It AFIIM -ISRA 2015

21. Basics Of MRI:How I Do It AFIIM -ISRA 2015
MR ARTHROGRAPHY
FSE T1
FSE T1 FAT SAT
FSE T2
3D FIESTA
Basics Of MRI:How I Do It AFIIM -ISRA 2015

22. T1 STERNO CLAVICULAR JOINT FLEX COIL
PROPELLER TO AVOID MOTION AND CARDIAC ATIFACTS T1 T2
Basics Of MRI:How I Do It AFIIM -ISRA 2015

23. Basics Of MRI:How I Do It AFIIM -ISRA 2015
STERNO CLAVICULAR JOINT
T1 AND T2 FSE
PROPELLER TO AVOID MOTION AND CARDIAC ATIFACTS T1 T2
Basics Of MRI:How I Do It AFIIM -ISRA 2015

24. Basics Of MRI:How I Do It AFIIM -ISRA 2015
TAKE HOME MESSAGE
AVOID MAGIC ANGLE
NO PD ON SHOULDER
AMAIZING
Basics Of MRI:How I Do It AFIIM -ISRA 2015

25. Basics Of MRI:How I Do It AFIIM -ISRA 2015