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Musculoskeletal MRI. Goals ► What types of MR studies are available for evaluation of the musculoskeletal system? ► Considerations when ordering a study.

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Presentation on theme: "Musculoskeletal MRI. Goals ► What types of MR studies are available for evaluation of the musculoskeletal system? ► Considerations when ordering a study."— Presentation transcript:

1 Musculoskeletal MRI

2 Goals ► What types of MR studies are available for evaluation of the musculoskeletal system? ► Considerations when ordering a study  Remember one of the roles of the radiologist is as consultant to work with you in determining the best study for the patient’s needs (it’s in the job description)… talk to them! ► Most common pathologies for which MSK MRI is performed

3 Exam Types Exam Types ► MRI without contrast  Most common  Evaluation of ligaments, tendons, occult fracture, cartilage ► MRI with contrast  Evaluation of bone or soft tissue tumor, osteomyelitis, abscess ► MR Arthrogram  Evaluation of labrum, intercarpal ligaments

4 Body Part ► When ordering any study must have a ddx in mind, particularly with MRI (not a screening tool) ► Cannot perform an MRI of a whole extremity (time, pt motion, protocol issues) ► Must identify part to be imaged – be specific  A joint, a bone (prox, mid, distal), a muscle (origin, belly, insertion) ► Must have plain radiograph

5 Most Common Indications ► Occult fx or stress fx ► Early osteonecrosis – in pt with risk factors & pain, known AVN of one hip ► Osteomyelitis – plain film is insensitive (30-50% loss of bone density) BUT necessary for MRI interpretation, nucs has poor resolution ► Osteochondral lesion – evaluate stability ► Ligament/tendon injury – knee, shoulder, ankle > other jts ► Bone tumor – MUST HAVE X-RAY 1 st, imperative in providing ddx on MRI (dx on x-ray, determine extent on MR) ► Soft tissue mass/muscle injury

6 Considerations when ordering an MRI ► Joint replacement in joint of interest – don’t do it ► Pacemaker – don’t do it ► Claustrophobia - sedation ► Unable to hold still/follow instructions – sedation ► Metal in area of interest (susceptibility artifact) – consult radiologist, may vary technique or recommend another study ► Metal not in area of interest ie. orbits (motion, overheating) ► If you only remember one thing, remember this:  cannot do a PE protocol chest CT without contrast

7 Metal Artifact Small metal foreign body results in large area of signal void. Metal or gas = black hole.

8 General Principles ► Fluid, edema, inflammation is bright on T2 ► Fat is bright on T1 & T2 (can have fat sat) ► Blood is often bright on T1 ► Tendons & ligaments are black on all sequences ► Cartilage is bright on T2 ► Muscle is intermediate in signal

9 Pelvis & Hip – Normal Anatomy ► Joints – sacroiliac, pubic symphysis, hips ► Tendons – iliopsoas, gluteal, hamstrings, rectus femoris ► Bursa – trochanteric, iliopsoas ► Bones – evaluate for bone marrow replacing process (MM, mets), AVN, occult or stress fx ► Acetabular labrum – need intra-articular gadolinium

10 Femoral Head Osteonecrosis ► Groin pain ► Many predisposing factors: trauma (fem neck fx, dislocation), steroids, SLE, sickle cell dz, pancreatitis, alcohol abuse, Gaucher’s dz ► Increased risk of contralateral AVN, must evaluate other side, most sensitive study is MRI ► MRI:  Early – bone marrow edema  Later – geographic area of abnormal signal in the anterosuperior femoral head; double line sign on T2  Even later – subchondral collapse, femoral head collapse, degenerative joint dz

11 Femoral Head Osteonecrosis

12 the other hip – 40% bilateral Anterior and superior femoral head

13 More examples of AVN

14 and more… Triple line sign?

15 Labral Tear ► Clicking, locking, pain with pivoting/twisting ► Traumatic (young), degenerative (older) or assoc. with femoroacetabular impingement (middle-aged) ► MRI:  Anterosuperior or posterosuperior  Linear high T2 signal  Loss of triangular morphology  Paralabral cyst ► MR arthrogram most sensitive study – contrast fills tear

16 Knee – Normal Anatomy ► Anterior & posterior cruciate ligaments ► Medial & lateral menisci ► Medial collateral ligament ► Lateral ligamentous complex (lateral collateral, iliotibial band, biceps femoris) ► Extensor mechanism ► Normal variant (discoid meniscus)

17 Knee – Normal Anatomy

18 ACL Tear ► Sports injury, rapid stopping/starting/pivoting (skiing, soccor, football, basketball etc), anterior drawer sign on PE ► MRI:  Disruption of fibers, high signal on T2  Pivot-shift contusions  Anterior translation of tibia relative to femur ► Associated with MCL and medial meniscus injury – O’Donahue’s unhappy triad ► Associated with Segond fx (avulsion of mid third lateral capsular ligament from lateral tibial plateau)

19 ACL Tear

20 ACL Tear – Pivot shift contusion

21 PCL Tear ► Dashboard injury of flexed knee, posterior drawer sign on PE ► MRI:  Disruption of fibers/thickened fibers  Abnormal high T2 signal  Avulsion at insertion on posterior tibia

22 PCL Tear

23 Meniscal Tear ► Joint line tenderness, clicking, locking ► MRI:  High T2 signal in the meniscus extending to the articular surface  longitudinal, radial, flap (flipped), oblique, bucket-handle  Parameniscal cyst

24 Oblique Undersurface Tear w/ Parameniscal Cyst

25 Bucket-handle Tear ► Medial > lateral ► Diminutive meniscus ► Inner edge of meniscus is displaced medially into notch ► Double PCL sign

26 Bucket-handle Tear

27 Discoid Meniscus ► Predisposes to early degeneration and tear of meniscus ► Lateral >> medial ► MRI:  Large meniscus, no longer C-shaped  Bowtie should not be seen on ≥3 consecutive sagittal images (4mm)

28 Discoid Meniscus

29 Medial Collateral Ligament Tear ► Valgus stress ► Complete or partial tears affecting superficial and/or deep fibers ► MRI:  Disruption of fibers with thickening & abnormal high signal ► Associated with ACL & medial meniscal tears ► Pellegrini-Stieda lesion – ossification at origin of MCL indicative of old tear

30 Medial Collateral Ligament Tear ► Pellegrini-Stieda lesion  Indicates old MCL tear  Ossification at origin of MCL from medial femoral condyle

31 Acute on chronic MCL tear

32 Patellar Tendon Tear ► Partial or complete ► Most commonly in proximal third of tendon at inferior pole of patella ► Plain film:  patella alta ► MRI:  Disruption of fibers, thickening & abn signal  Fluid-filled gap, hemorrage or granulation tissue

33 Patellar Tendon Tear

34 Patellar Tendon Tear different patient

35 Jumper’s Knee (Patellar Tendinosis) ► Repetitive trauma ► MRI:  Proximal third of patellar tendon (posterior fibers)  Early – edema in peritenon  Later - thickening & edema (inc T2)  Even later – partial or complete tear  +/- reactive osteitis in lower pole patella (edema)  Reactive edema in adjacent fat pad

36 Jumper’s Knee

37

38 Osteochondral Lesion ► Young male, 50% have h/o trauma ► Lateral aspect of medial femoral condyle, talar dome, capitellum ► Plain film: area of sclerosis or bone/cartilage fragment in situ or defect with loose body in joint ► MRI necessary to determine stability and guide treatment (stable-heal spontaneously, unstable-surgery) ► MRI:  Fragment composed of hyaline articular cartilage and underlying subchondral bone  Unstable if fluid between fragment and donor site on T2

39 OCD

40 OCD

41 Ankle – Normal Anatomy ► Joints – tibiotalar, distal tibiofibular, subtalar (ant, middle, post), intertarsal ► Tendons – flexor (tibialis posterior, digitorum longus, hallucis longus), extensor (tibialis anterior, hallucis longus, digitorum), peroneus (longus, brevis), Achilles ► Ligaments – medial (deltoid), lateral (talofibular, talocalcaneal), syndesmotic, Lis-Franc ► Muscles, bones, plantar fascia ► Normal Variants – plantaris, accessory soleus

42 Tarsal Coalition ► Lack of segmentation of two tarsal bones ► Most commonly calcaneonavicular or talocalcaneal (middle subtalar joint) ► 20% bilateral; pain, flat foot ► Cartilaginous, fibrous, osseous ► Plain film: anteater sign, continuous C sign, talar beak, pes planus ► MRI:  Cartilaginous, fibrous or bony bridge between 2 tarsal bones  Fibrous/cartilaginous - JSN, irregularity, sclerosis, bone marrow edema  Bony – continuity of bone marrow and cortex

43 Talocalcaneal Coalition

44 Calcaneonavicular Coalition

45

46 Accessory Soleus Muscle

47 Accessory Soleus

48 … and OCD Stable or unstable?

49 Peroneus Brevis Split Tear ► Peroneus brevis is normally round and anterior to longus ► Tear most commonly at level of lateral malleolus ► MRI:  C-shaped tendon  Longitudinal split, peroneus longus may be interposed between two subtendons  +/- fluid in tendon sheath (tenosynovitis)

50 Peroneus Brevis Split Tear Tom Dick Harry Achilles Peroneus tendons Talar dome

51 Stress Fracture ► 2 types of stress fractures: 1.Fatigue fx – normal bone under abnormal stress (young marathon runner, military recruit etc…) 2.Insufficiency fx – abnormal bone under normal stress (elderly osteopenic female, steroids etc…) ► Characteristic locations: 3 rd metatarsal, tibial diaphysis, calcaneus, medial aspect femoral neck, sacrum ► Plain film:  Cortical bone – periosteal rxn and/or endosteal thickening  Cancellous bone - ill-defined sclerosis ► MRI:  Low signal line on T1  High signal bone marrow edema on T2  Calcaneus – trabecular fractures perpendicular to long axis

52 Stress Fracture

53

54

55 Brachial Plexus – Normal Anatomy ► Ventral nerve roots of C5, C6, C7, C8 & T1 ► Coarse between anterior & middle scalene muscles, under clavicle, over 1 st rib, adjacent to subclavian artery (post & sup) ► Normal MRI appearance:  Fascicles well-defined with intervening fat

56 Brachial Plexus - Normal Cor T1Sag T1

57 Brachial Plexopathy ► Pain in the shoulder radiating down arm ► Etiologies: radiation >60 Gy(breast, lung ca), metastatic disease (via axillary lymphatics), direct invasion by tumor (Pancoast’s, lymphoma), direct trauma, stretch injury ► MRI:  Thickened fascicles with obliteration of the intervening fat planes  Well-defined mass

58 Radiation-induced Brachial Plexopathy Which side is abnormal?

59 Radiation-induced Brachial Plexopathy ► Which number corresponds to the brachial plexus? ► What are the other 2 structures? Subclavian artery Subclavian vein 1 2 3

60 Brachial Plexus Metastasis Cor & Sag T1

61 Brachial Plexus Metastasis Subclavian artery Vein Mass Pre and post-contrast cor T1 with fat sat

62 Shoulder – Normal Anatomy ► Rotator cuff ► Long head of the biceps brachialis tendon – intertubercular and intracapsular portions ► AC joint/impingement ► Glenoid labrum – triangular low signal on all sequences, serves to deepen glenoid fossa thereby stabilizing GH joint, attachment site of long head of biceps  Myxoid degeneration, labral tear (alphabet soup), Bankart lesion  Best evaluated with MR arthrography

63 Normal Anatomy

64 Rotator Cuff Tear ► Supraspinatus, infraspinatus, teres minor, subscapularis ► Pts > 40 yo, insidious onset of pain ► Spectrum: tendinopathy, partial and full thickness tear ► Etiology: degeneration (age, overuse, impingement), trauma, collagen vascular disease ► MRI:  Tendinopathy – thickened tendon, increased signal on PD, intermed on T2  Partial tear – increased signal on T2, defect does not extend through cuff  Complete tear – increased signal defect on T2 extending through RC from articular surface to bursal surface; fluid in subacromial/subdeltoid bursa  Chronic tear – muscle atrophy

65 Rotator Cuff Tear Supraspinatus

66

67 Supraspinatus Tendinopathy ► Underlying degenerated tendon as evidenced by thickening and abnormal signal

68 Labral Tear ► Young pts <40 yo, pain, instability ► Best evaluated with MR arthrogram ► MRI:  Linear high T2 signal within substance of labrum  Diffuse high signal (crush injury)  Absent or small labrum  Detached labrum ► Mimics:  Undercutting of articular cartilage between labrum and glenoid  Interposed synovial recess (sulcus)  Sublabral foramen/hole (detached anterosuperior labrum)

69 Labral Tear

70 Labral Tear? ► NO ► Undercutting of cartilage between labrum & glenoid ► Interposed synovial sulcus ► Contrast follows contour of glenoid (points medially)

71 Hillsach’s and Bankart Lesions ► History of anterior shoulder dislocation ► Hillsach’s – impaction fracture of posterior superior humeral head ► Bankart – anterior inferior labral avulsion w/ rupture of periosteum, many variants ► Bony Bankart – fracture of anterior glenoid ► MRI:  Impaction fracture of posterosuperior humeral head (not round on 1 st three axial images)  Anterior labral tear or variant (best evaluated with arthrography)

72 Hillsach’s and ALPSA

73 Elbow – Normal Anatomy ► Tendons – biceps, brachialis, triceps, common flexor and extensor origins ► Ligaments – ulnar and radial collateral ► Joints – elbow, proximal radioulnar ► Olecranon bursa

74 Olecranon Bursitis ► Painless mass following acute direct trauma or recurrent trauma; assoc with systemic dz ► Distension of olecranon bursa (synovial sac) with fluid ► MRI:  In superficial soft tissues adjacent to olecranon process and triceps insertion  mm – cm in size  High signal on T2, possible rim enhancement  +/- hemorrhagic debris

75 Olecranon Bursitis

76 Lateral Epicondylitis ► Insidious onset of lateral elbow pain with activity ► Overuse syndrome – repetitive varus stress ► Chronic tendinopathy at common extensor origin, predominantly involving the extensor carpi radialis brevis tendon  Partial avulsion with scar formation ► Plain film: normal or spur at lateral epicondyle ► MRI:  Thickening of tendon with increased signal on T1 & T2

77 a.k.a Tennis Elbow Tendinosis with small tear

78 Lateral Epicondylitis Involves both deep and superficial fibers of extensor carpi radialis longus

79 Wrist – Normal Anatomy ► Bones – distal radius & ulna, carpus, MT’s ► Joints – DRUJ, radiocarpal, intercarpal ► Tendons – flexor & extensor ► Nerves – median & ulnar ► Ligaments – intercarpal (instability) ► Masses – most common ganglion cyst

80 Status post trauma Where is the fracture?

81 Occult Distal Radius Fx


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