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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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