MSK Imaging MSK ImagingMSK ImagingMSK ImagingMSK Imaging

MSk imaging

1. Musculoskeletal Imaging Nguyen Van Anh, MD, Msc Wallace T. Miller, Jr. M.D.

2. Objective To learn how to think through medical problems using imaging

3. My Expectations That you attempt to answer the questions Try to think about the problem logically Even if you are confused or uncertain make your best guess

4. Learning Outcomes After this lecture you should be able to : Describe imaging features of fractures (“ the language of fractures”) Recognize features of Avulsion fractures Growth plate fractures Greenstick fractures Pathologic fractures Explain how imaging characteristics may identify the mechanism underlying the fracture Describe and explain the clinical significance of the Salter-Harris classification system . List the common causes of focal bone lesions Construct a differential diagnosis (for focal lesions) and identify the most likely diagnoses using clinical history , imaging findings , demographics and relative frequency of disease.

5. 28 year old man with trauma to the left forearm What is abnormal? Case 1

6. 28 year old man with trauma to the left forearm What is abnormal? Fracture of the radius How do we describe fractures? Case 1

7. 28 year old man with trauma to the left forearm What is abnormal? Fracture of the radius How do we describe fractures? Case 1

8. “Language of Fractures” 2 1. Location Which bone Where on the bone Epiphysis Metaphysis Diaphysis 2. Direction of the fracture Transverse (more stable) Oblique (less stable) Spiral (less stable) 3. Orientation of the fragments Angulation Rotation Displacement 4. Over-riding vs distracted 5. Joint involvement Risk - premature arthritis 6. Disruption of the skin “Closed” vs “Open” Risk - infection

9. 28 year old man with trauma to the left forearm What is abnormal? Fracture of the radius Describe this fracture Transverse fracture of radius at the juncture of the middle and distal thirds Posterior displacement of the distal fragment the width of the shaft Fragments over-ride approximately 1 cm What is the second abnormality? Case 1

10. Dislocation of the ulna at the wrist What is the second abnormality? The ulna, radius and wrist and elbow joints form a bony ring 28 year old man with trauma to the left forearm Case 1

11. Trauma to bony rings will nearly always result in disruption of the ring in two places A break in the ring should lead to a search for a second break 28 year old man with trauma to the left forearm Bony Rings Where are there other bony rings?

12. Trauma to bony rings will nearly always result in disruption of the ring in two places A break in the ring should lead to a search for a second break 28 year old man with trauma to the left forearm Bony Rings Where are there other bony rings? Distal leg Pelvis Vertebra Rib cage an exception to the rule!

13. Galeazzi Fracture Mechanism Trauma to the ventral forearm Fracture of the radius dislocation of the ulna at the wrist Rings break in 2 places Monteggia Fracture Obverse fracture Blow to dorsal forearm Fracture of ulna Dislocation of radius at elbow

14. 22 man twisted ankle playing basketball Case 2 What is abnormal?

15. 22 man twisted ankle playing basketball Case 2 What is abnormal?

16. 22 man twisted ankle playing basketball Case 2 What is abnormal? Bimalleolar Fracture Fracture of the distal fibula Fracture of the distal tibia What is the mechanism ? Inversion (foot turns inward) Eversion (foot turns outward) The tibial fracture is an example of a specific type of fracture. What is the name ?

17. 22 man twisted ankle playing basketball Case 2 What is abnormal? Bimalleolar Fracture Fracture of the distal fibula Fracture of the distal tibia What is the mechanism ? Inversion (foot turns inward) Eversion (foot turns outward) The tibial fracture is an example of a specific type of fracture. What is the name ? Avulsion Fracture What is the mechanism?

18. Mechanism Distraction of ligament or tendon Avulsion of bone fragment at the site of attachment Avulsion Fractures 22 man twisted ankle playing basketball What does the tibial avulsion fracture tell us about the mechanism of the bimalleolar fracture ? Inversion (foot turns inward) Eversion (foot turns outward)

19. Eversion-Related Bimalleolar Fracture Mechanism Eversion of the ankle leads to… Avulsion of the medial malleolus leads to … Lateral deviation of the talus leads to … Oblique fracture of the lateral malleolus What would an inversion-related bimalleolar fracture look like?

20. Eversion-Related Bimalleolar Fracture Mechanism Eversion of the ankle leads to… Avulsion of the medial malleolus leads to … Lateral deviation of the talus leads to … Oblique fracture of the lateral malleolus What would an inversion-related bimalleolar fracture look like? Inversion-related Bimalleolar Fracture Avulsion of the lateral malleolus Medial deviation of the talus Oblique fracture of the medial malleolus

21. Man fell off a roof Image windowed to see soft tissues Image windowed to see bone Case 3 What are the abnormalities?

22. Man fell off a roof Image windowed to see bone Case 3 What are the abnormalities? Comminuted fracture of the calcaneus Typical of fall from height landing on feet Axial load “Jumper’s” fracture

23. Man fell off a roof Image windowed to see bone Case 3 What are the abnormalities? Comminuted fracture of the calcaneus Typical of fall from height landing on feet Axial load “Jumper’s” fracture What are the associated injuries?

24. Man fell off a roof Image windowed to see bone Case 3 What are the abnormalities? Comminuted fracture of the calcaneus Typical of fall from height landing on feet Axial load “Jumper’s” fracture Fractures of Axial Loading Jumper’s fracture Burst fracture and/or Compression fracture of the thoraco-lumbar spine Examine/image the spine! Pelvic fractures Examine/image the pelvis! What are the associated injuries?

25. Man fell off a roof Image windowed to see soft tissues Case 3 Why did I include an image windowed to soft tissue?

26. Man fell off a roof Image windowed to see soft tissues Case 3 Why did I include an image windowed to soft tissue? Bubbles of gas! Source of the gas?

27. Man fell off a roof Image windowed to see soft tissues Case 3 Why did I include an image windowed to soft tissue? Bubbles of gas! Sources of soft tissue gas From the outside (laceration) From the lung From the bowel Gas forming infection What source in our case? Source of the gas?

28. Man fell off a roof Image windowed to see soft tissues Case 3 Why did I include an image windowed to soft tissue? Bubbles of gas! Sources of soft tissue gas From the outside (laceration) From the lung From the bowel Gas forming infection Open Fracture What source in our case? Source of the gas?

29. Open “Jumper’s” Fracture Comminuted fracture of calcaneus Fall from a height Axial load Associated fractures Compression fracture (T 12 -L 1 ) Burst fracture (T 12 -L 1 ) Pelvic fracture Open injury Risk of infection!

30. 6 year old boy fell from a tree Case 4 What is abnormal?

31. 6 year old boy fell from a tree Case 4 What is abnormal? Fracture of the radius What is the name for this type of fracture?

32. 6 year old boy fell from a tree Case 4 What is abnormal? Fracture of the radius What is the name for this type of fracture? Salter-Harris Fracture Fracture involving the growth plate What are the types of Salter-Harris fractures What is the significance?

33. Increasing likelihood of arrested growth Salter Harris Fractures I II III IV V Why is III worse than II?

34. Increasing likelihood of arrested growth Blood supply to physis is from epiphysis Fracture epiphysis may infarct the physis Stop growth at that location – Bone may grow crooked Salter Harris Fractures I II III IV V Bone fusion due to infarcted growth plate Continued growth

35. 6 year old boy fell from a tree Case 4 What is abnormal? Salter-Harris Fracture Fracture involving the growth plate Prognosis for arrested growth What class of Salter-Harris fracture does the boy have?

36. Type II Salter-Harris Fracture Fracture through growth plate Higher the number the greater the likelihood of growth disturbance Epiphyseal fracture worse Epiphysis provides blood to the physis Fracture may infarct the physis Metaphysis Epiphysis Metaphyseal fragment Epiphysis and metaphyseal fragment remain connected Ulnar epiphysis

37. 13 year old boy fell while riding his bicycle Case 5 What is abnormal?

38. 13 year old boy fell while riding his bicycle Case 5 What is abnormal?

39. 13 year old boy fell while riding his bicycle Case 5 What is abnormal? Incomplete fracture of the radius What is the name for this type of fracture?

40. 13 year old boy fell while riding his bicycle Case 5 What is abnormal? Incomplete fracture of the radius What is the name for this type of fracture? Torus Fracture “Green-stick” fracture “Buckle” fracture Who gets torus fractures? Why?

41. Torus Fracture Incomplete fracture Early adolescence Mechanism Rapid growth Relatively less matrix Bone less hard – bends Collagen prevents breaking Synonyms “Greenstick” fracture ”Buckle” fracture

42. Case 6 What is abnormal? Older woman with acute arm pain after stumbling

43. Older woman with acute arm pain after stumbling Case 6 What is abnormal?

44. Older woman with acute arm pain after stumbling Case 6 What is abnormal? Oblique fracture of the humerus Why did she get this fracture? What do you think of the underlying bone structure?

45. Older woman with acute arm pain after stumbling Case 6 What is abnormal? Oblique fracture of the humerus Why did she get this fracture? What do you think of the underlying bone structure? Cortex of distal humerus relatively normal Proximal cortex appears “moth eaten” Innumerable small holes What is the name for this type of fracture?

46. Insufficiency Fracture Underlying bone abnormal Bone fractures under low levels of stress “ Pathologic ” fracture Is underlying bone disease? 1. Focal 2. Diffuse Older woman with acute arm pain after stumbling

47. Insufficiency Fracture Underlying bone abnormal Bone fractures under low levels of stress “ Pathologic ” fracture Is underlying bone disease? 1. Focal 2. Diffuse Cortex distal humerus normal Older woman with acute arm pain after stumbling

48. Focal Bone Diseases Neoplasms Metastasis Multiple myeloma Other primary bone neoplasms Infection (osteomyelitis) Infarction (AVN) Trauma 1 2 3 4 5 Older woman with acute arm pain after stumbling

49. Pathologic Fracture due to Metastatic Breast Carcinoma Fracture from normal stress on an abnormal bone Permeative destruction of the proximal humerus Holes in bone in patients over 50 years = metastasis or myeloma

50. 47 woman with DM complains of foot pain and swelling w skin ulcer Case 7 What is abnormal?

51. 47 woman with DM complains of foot pain and swelling w skin ulcer Case 7 What is abnormal?

52. 47 woman with DM complains of foot pain and swelling w skin ulcer Case 7 What is abnormal? Lytic lesion base 5 th metatarsal (red arrow) Gas in soft tissues (yellow arrow) Cause of focal bone lesions 1. Metastasis 2. Multiple myeloma 3. Primary neoplasm 4. Osteomyelitis 5. AVN 6. Fracture

53. Plain film findings Bone erosion Periosteal new bone formation Late in disease Most sensitive imaging MRI Bone edema PET-CT Increased metabolic activity Patients at risk Diabetes mellitus Penetrating wounds Sepsis Orthopedic hardware Osteomyelitis

54. MRI Bone edema Normal marrow contains fat (yellow arrow) which is bright on T1W Edema (red arrows) dark on T1W Osteomyelitis Sagittal T1W MRI

55. Case 8 What is abnormal? Lytic lesion of the distal femoral metaphysis surrounded by a thick dense rim of reactive sclerosis, orientated along the long axis of the bone and extending to the epiphysis through the growth plate. Cause of focal bone lesions 1. Metastasis 2. Multiple myeloma 3. Primary neoplasm 4. Osteomyelitis 5. AVN 6. Fracture 10yo boy – painful right knee with fever, tenderness

56. Case 8 10yo boy – painful right knee with fever, tenderness

57. Intraosseous abscess Related to a focus of subacute or chronic pyogenic osteomyelitis Xray: lytic lesion + sclerotic rim, periosteal reaction.. MRI: “penumbra sign”  DDx: osteoid osteoma, chondroma, chondroblastoma, mets , sarcoma… Brodie abscess

58. 27 man right knee pain Case 9 What is abnormal?

59. 27 man right knee pain Case 9 What is abnormal? Lytic lesion proximal tibia Cause of focal bone lesions 1. Metastasis 2. Multiple myeloma 3. Primary neoplasm 4. Osteomyelitis 5. AVN 6. Fracture

60. Bone Malignancy Over 50 years old Metastasis Multiple myeloma Under 40 years old Primary malignancies But still rare! Imaging evaluation Metastasis CT PET-CT (most sensitive) Primary malignancy MRI  (Best delineation of extent of disease) Giant Cell Tumor T1W MRI T2W MRI w fat sat

61. 13yo boy, left knee pain Case 10 What is abnormal? Sclerotic lesion proximal tibia Cause of focal bone lesions 1. Metastasis 2. Multiple myeloma 3. Primary neoplasm 4. Osteomyelitis 5. AVN 6. Fracture

62. Bone Cancer Adolescents Non-specific pain Metadiaphysis of long bones (around knee) Ossification matrix, wide zone of transition Cortical destruction Aggressive periosteal reactions Soft-tissue mass Osteosarcoma

63. Imaging Features of Fractures “Language of Fractures” 2 1. Location Which bone Where on the bone Epiphysis Metaphysis Diaphysis 2. Direction of the fracture Transverse (more stable) Oblique (less stable) Spiral (less stable) 3. Orientation of the fragments Angulation Rotation Displacement 4. Over-riding vs distracted 5. Joint involvement Risk - premature arthritis 6. Disruption of the skin “Closed” vs “Open” Risk - infection Summary

64. Type of fractures can provide information about Etiology of the fracture Mechanism of the fracture Insufficiency Fx “Pathologic” Types of Fractures Torus Fx “Greenstick” Salter-Harris Fx Growth plate Avulsion Fx

65. Fracture distribution often gives insight into the mechanism the risk of other injuries Mechanisms of Fractures Fractures of Axial Loading Jumper’s fracture Burst fracture and/or Compression fracture of the thoraco-lumbar spine Examine/image the spine! Pelvic fractures Examine/image the pelvis! Boney Rings A break in a ring should lead to a search for a second break Bimalleolar Fracture Fracture characteristics tell the mechanism Inversion Eversion

66. Increasing likelihood of arrested growth Blood supply to physis is from epiphysis Fracture epiphysis may infarct the physis Stop growth at that location – Bone may grow crooked Salter Harris Fractures I II III IV V Bone fusion due to infarcted growth plate Continued growth

67. Focal Bone Diseases Neoplasms Metastasis Multiple myeloma Other primary bone neoplasms Infection (osteomyelitis) Infarction (AVN) Trauma