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The Basics

Interpretation of Knee and Shoulder MRI for the Nonradiologist

Department of Radiology New England Baptist Hospital

· All magnets are not created equal 1.5 Tesla 1.0T 0.7T open 0.3T open 1.0T extremity Newest 3T

Conventional high-field MRI high-

Open MRI

Extremity Magnet

The Basics

· Coil ­ extremity, shoulder · Imaging planes ­ at least three · Sequences SE/FSE - T1, proton density, T2 fat-suppression fatgradient-echo gradient-

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Knee MRI

· Indications ­ pain, injury · Imaging planes ­ sagittal, axial, coronal · Sequences ­ vary by institution

Knee MRI ­ Sagittal Images

· Menisci · Cruciate ligaments · Articular cartilage · Other ­ extensor mech., bone marrow

Sagittal Images ­ Lateral Meniscus

Sagittal Images ­ Medial Meniscus

Sagittal Images ­ ACL/PCL

Knee MRI ­ Axial Images

· Patellofemoral joint · Cruciate ligaments · Popliteal fossa

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Axial Images

Knee MRI ­ Coronal Images

· Menisci · Ligaments ­ collateral, cruciate · Other ­ articular cartilage, bone marrow

Coronal Images - Menisci

Coronal Images ­ Collat. Ligs. Ligs.

Menisci

Meniscal Pathology

· Degeneration

· Medial · Tear ­ extends to meniscal surface · Lateral · Discoid (lateral)

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Meniscal Tear

Meniscal Tear

Meniscal Tear

Meniscal Tear

Meniscus­ Bucket-Handle Tear Meniscus­ Bucket-

Cruciate Ligaments

· ACL ­ courses from medial LFC to

anterior intercondylar tibia

· PCL ­ courses from inner MFC to

posterior intercondylar tibia

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Cruciate Ligament Injury

· ACL>>PCL · MRI findings ­ swelling, disruption,

ACL Tear

abnormal signal, orientation

· Secondary signs

normal

tear

ACL Tear

ACL Tear ­ Bone Bruises

acute

chronic

PCL Injury

PCL Injury

normal

torn Proton-density T2-weighted

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Collateral Ligaments

· Medial ­ MFC to medial tibia, attaches

MCL Injury

4/5cm below joint line

· Lateral complex iliotibial band fibular collateral ligament biceps femoris tendon popliteus tendon

normal torn

MCL Sprain

Lateral Ligament Injury

Knee MRI ­ Bone Marrow

· Contusion · Occult fracture · AVN

Bone Contusion

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Shoulder MRI

· Indications ­ pain, injury, impingement,

Shoulder MRI ­ Anatomy

· Rotator Cuff supraspinatus infraspinatus teres minor subscapularis

instability

· Imaging planes ­ oblique coronal, oblique

sagittal, axial

· Sequences ­ vary by institution

Shoulder MRI - Anatomy

· Biceps tendon ­ long head · Labrum ­ anterior, posterior, superior · Acromioclavicular joint · Acromion - shape

Oblique Coronal PD

Oblique Coronal PD

Oblique Coronal PD

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Oblique Coronal T2

Oblique Coronal T2

Oblique Sagittal T2

Oblique Sagittal T2

Oblique Sagittal T2

Axial PD

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Axial PD/GRE

Rotator Cuff Pathology

· Tendinopathy · Tear contour disruption focal defect with fluid signal on T2WI complete absence full vs. partial thickness

Normal Supraspinatus Tendon

Normal Supraspinatus Tendon

Proton-density

T2-weighted

coronal

sagittal

Supraspinatus Tear

Supraspinatus Tear

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Supraspinatus Tear

Supraspinatus Tear

Proton-density

T2-weighted

oblique sagittal T2-weighted

Large Cuff Tear ­ Open MRI

Large Cuff Tear ­ Open MRI

T1

T2

cor T2 - infraspinatus

sagittal T2

Biceps Tendon

Take Home Points

· Interpretation of extremity MRI appreciate complex anatomy imaging planes ­ which orientation best depicts a given structure spectrum of pathology and normal variation No skipping!! ­ All structures must be examined!

normal biceps/subscapularis

Subluxed biceps and torn subscapularis

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Information

11 pages

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