Diagnostic Imaging of Bone Infection

1. Musculoskeletal
Bone Infection

2. Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

5. Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

6. Bone Infection
a) Osteomyelitis
b) Pott’s Disease
c) Congenital Infections

7. a) Osteomyelitis :
1-Incidence
2-Etiology
3-Location
4-Radiographic Features

8. 1-Incidence :
-Refers to bony inflammation that is almost
always due to infection, typically bacterial
-Osteomyelitis can occur at any age, in
those without specific risk factors it is
particularly common between the ages of
2-12 years of age and is more common in
males

9. 2-Etiology :
-Bacteria pass through nutrient vessels to
metaphyses where organisms proliferate,
metaphyseal inflammatory reaction progresses
to edema, pus, necrosis, thrombosis, in older
children, the cartilaginous growth plate becomes
avascular and acts as a barrier to epiphyseal
extension
-Three routes of infection are recognized :
1-Hematogenous route (most common in
pediatrics)
2-Direct inoculation
3-Local extension from contiguous infection

10. -Children (unifocal) : Staphylococcus (85%),
Streptococcus (10%)
-Neonates (multifocal) : Streptococcus,
Staphylococcus
-Immunocompromised adults : short bones of hand
and feet : Staphylococcus
-Drug addicts : Pseudomonas (85%), Klebsiella
-Sickle cell disease : Salmonella
-In otherwise healthy adults, hematogenous
osteomyelitis is very rare, osteomyelitis in adults
usually follows direct implantation after surgery
or trauma

11. 3-Location :
-Tubular bones with most rapid growth and largest
metaphyses are most commonly affected, 75% :
femur > tibia > fibula; distal end > proximal end
-Flat bones are less frequently infected, 25% :
vertebral bodies, iliac bones
-Neonates : metaphysis and/or epiphysis
-Children : metaphysis
-Adults : epiphyses and subchondral regions

12. 4-Radiographic Features :
1-Plain Radiography
2-MRI
3-Nuclear Medicine

13. 1-Plain Radiography :
a) Soft tissue swelling :
-Earliest sign
-Often in the metaphyseal region
-Loss or blurring of normal fat planes
b) Regional osteopenia
c) Cortical loss , 5 to 7 days after infection, bone
destruction
d) periosteal reaction / thickening

14. Soft tissue swelling with bone destruction

15. OM of RT tibia in a neonate

16. OM distal radius

17. Diabetic OM

18. Thumb OM

19. OM humerus

20. Bone destruction of head of 2nd metatarsal with periosteal new bone formation
characteristic of osteomyelitis

21. Periosteal reaction

22. A periosteal reaction can be seen and the femur is osteopaenic

23. Periosteal elevation (left-image arrowhead) and osteolysis (right-image
arrowhead) findings consistent with osteomyelitis

24. e) In untreated cases eventual formation of :
1-Sequestrum :
-Devascularization of a portion of bone with
necrosis and resorption of surrounding bone
leaving a floating piece
-In some instances the sequestrum becomes
encased in a thick sheath of periosteal new bone
known as an involucrum
2-Involucrum :
-Thick sheath of periosteal new bone surrounding
a sequestrum
3-Cloaca :
-Space in which dead bone resides

25. Sequestrum

28. T1 T2

29. f) Chronic Osteomyelitis :
1-Brodie's abscess :
-Lucent well-defined lesion with thick sclerotic rim
-Lucent tortuous channel extending toward growth
plate prior to physeal closure (pathognomonic)
-Typically in metaphysis or diaphysis of long bones
2-Thick and dense cortex
3-Sinus tracts to skin

30. Brodie's abscess

31. Brodie's abscess

32. Brodie's abscess

33. Brodie's abscess

34. *N.B. : Sclerosing osteomyelitis of Garre:
-A specific type of chronic osteomyelitis
-It mainly affects children and young adults
-It typically affects the mandible and is commonly
associated with an odontogenic infection resulting from
dental caries
-Orthopantomogram (OPG) :
*A localized overgrowth of bone on the outer surface of the
cortex, this mass of bone, which is supracortical but
subperiosteal, is smooth, fairly calcified, and is often
described as a duplication of the cortical layer of the
mandible
*Redundant cortical layering of the bone (onion skinning): is
often considered a pathognomonic feature

35. Sclerosing osteomyelitis in a 10-year-old boy, CT scan shows diffuse
sclerotic changes with expansion of the left mandibular body
(arrows), note the diffuse soft-tissue swelling (arrowheads)

36. Coronal CT in a 7-year-old girl with sclerosing osteomyelitis
demonstrates osseous sclerosis, remodelling, periosteal new bone
(arrowhead), and soft tissue swelling (arrow)

37. 2-MRI :
-Bone marrow hypointense on T1 +
hyperintense on T2 (water-rich
inflammatory tissue)
-Post contrast enhancement of bone
marrow, abscess margins, periosteum and
adjacent soft tissue collections

38. T1 T2 T1+C

39. 3-Nuclear Medicine :
a) Ga-67 scans :
-100% sensitivity
-Increased uptake 1 day earlier than for Tc-
99m MDP
-Gallium helpful for chronic osteomyelitis

40. b) Static Tc-99m Diphosphonate :
-83% sensitivity
-5 to 60% false negative rate in neonates and children
-Radionuclide images of the region of interest during an
angiographic phase (blood flow phase) , a blood pool
phase (tissue phase) and a delayed phase
-There is no osteomyelitis without abnormal radionuclide
uptake on the images obtained during the delayed phase
-N.B. :
*Differential Diagnosis for patients with a normal radiograph
and focal increased radionuclide uptake in a single bone:
1-Occult fracture such as a toddler’s fracture
2-Osteod osteoma

41. b) Pott’s Disease :
1-Incidence
2-Radiographic Features
3-Differential Diagnosis

42. 1-Incidence :
-Also known as tuberculous spondylitis
-Refers to vertebral body and intervertebral
disc involvement with tuberculosis
-N.B. :
Brucellosis can present as granulomatous
osteomyelitis of the spine that can be
difficult to distinguish from TB

43. 2-Radiographic Features :
1-Bone destruction is prominent, more prolonged onset
than with pyogenic bone destruction
2-Loss of disk height, 80% (affects intervertebral discs, but
mets no)
3-Gibbus deformity : anterior involvement with normal
posterior vertebral bodies (Kyphosis)
4-Vertebra plana or pancake vertebra (vertebral body has
lost almost its entire height anteriorly and posteriorly)
5-Involvement of several adjacent vertebral bodies with
disk destruction
6-Large paraspinous abscess
7-Extension into psoas muscles (psoas abscess)

44. Destructive processes involving T11 associated with kyphosis

50. With paravertebral abscess

51. With paravertebral abscess

52. 3-Differential Diagnosis :
-From non-specific infections :
a) Site :
-Lumbar vertebrae are more affected in non-specific
infections
-T.B. : Cervical , dorsal then lumbar
b) Course :
-Acute with non-specific and prolonged in T.B.
c) Soft tissue mass , collapsed vertebrae :
-More with T.B.
d) Sclerosis :
-More with non-specific infections

53. c) Congenital Infections : Celery stalking
1-Incidence
2-Radiographic Features

54. 1-Incidence :
-Rubella, bone changes in 50% of patients
-Syphilis, musculoskeletal involvement is
much more common, 95% of the time

55. 2-Radiographic Features :
-Celery stalking of metaphysis with longitudinally
aligned linear bands of sclerosis
-Periosteal reaction :
*Absence in rubella
*Prominent in syphilis
-Rubella : delayed appearance of epiphyses
-Syphilis : Wimberger's sign (bilateral destructive
lesion on medial aspect of proximal tibial
metaphysis)

56. Celery stalking of metaphysis

57. Congenital rubella in a newborn male demonstrates
shows fraying and longitudinal alternating
radiolucent and radiodense stripes (celery stalking)
Congenital syphilis in a 2-month old female shows
marked periosteal reaction with destruction of the
proximal medial tibial metaphyses (Wimberger
corner sign).

58. Wimberger’s sign

59. Celery stalking of metaphysis

60. Celery stalking of metaphysis

61. *N.B. :
Celery stalking of metaphysis is seen in :
1-Congenital infections
-Congenital rubella
-Congenital syphilis
-Congenital CMV
2-Osteopathia striata