imaging features

1. BONE AND JOINT
INFECTION
DR. ATHUL . D

2. ACUTE OSTEOMYELITIS
earliest radiographic signs of bone infection: a
poorly defined osteolytic area of destruction
in the metaphyseal segment of the distal
femur (arrow) and soft-tissue swelling

3. destruction of the cortical
and medullary portions of
the metaphysis and
diaphysis of the
distal femur, together with
periosteal new bone
formation. Note the
pathologic fracture
(arrows). On the
lateral view, a large
subperiosteal abscess is
evident (arrowheads).

4. Active osteomyelitis. Sequestra surrounded by
involucrum, as seen here in the left fibula of a
2- year-old child, is a feature of advanced
osteomyelitis, usually apparent after 6 to 8
weeks of active infection
Sequestrum – a piece of devitalized bone
during necrosis.
Involucrum – thick sheath of periosteal new
bone surrounding a sequestrum.

5. diabetic man demonstrate an active osteomyelitis of the calcaneus.
Note several high-attenuation osseous fragments representing
sequestra

6. Osteomyelitis with abscesses in a
child. (A) AP
radiograph of the left knee showing a
lucent metaphyseal lesion of the tibia
with surrounding sclerosis.
(B) Axial and (C) coronal
post-contrastT1-weighted fat-saturated
images confirm the presence of a bone
abscess, with surrounding oedema of
the metaphysis.

7. OSTEOMYELITIS
• MRI is the investigation of choice for the diagnosis of acute, subacute and chronic
osteomyelitis.
• Acute osteomyelitis in children
• bone marrow oedema, which is seen as low T1 signal in the bone marrow, along with
high signal on T2 and STIR images

8. features of chronic osteomyelitis.
There is sclerosis and diffuse periosteal new bone formation
diffuse bone sclerosis with multiple
cavities and cloaca

9. CHRONIC OSTEOMYELITIS
increased bone density
and cortical thickening on the left
side due to chronic osteomyelitis.
There is bone destruction from an
associated dental abscess around
the roots of the remaining teeths

10. cortical thickening and chronic periosteal
new bone formation, forming an involucrum
around an indistinct medullary cavity.There is a
cloaca.

11. lytic destructive bone lesions
containing
central sequestra in the sternum
and spine. Pulmonary nodules
are also present, due to
disseminatedTB.
Chronic osteomyelitis with sequestra

12. Anteroposterior radiograph shows thickening of
the medial cortex of tibia and a radiolucent
tract extending from the medullary cavity to
the soft tissues

13. Axial CT section shows
a sinus tract and a low-attenuation sequestrum (arrow).
(C) Coronal and sagittal reformatted CT images clearly
demonstrate the intraosseous sinus containing several sequestra.

14. intravenous administration of gadolinium show
enhancement of bone marrow indicative
of osteomyelitis, sinus tract (arrow), and soft-
tissue abscess with ring enhancement (curved
arrow).

15. The cloaca is clearly seen in coronal images as a focus of
hyperintense signal surrounded by a low signal area

16. ADVANTAGES OF CT OVER MRI
• Demonstrate periosteal reaction, subtle bone erosion, cortical
destruction, abscess formation and soft-tissue swelling.
• thickening of trabeculae and medullary abnormalities.
• cortical destruction and demonstrating the presence of gas
• demonstration of sequestra, involucra and cloacae

17. MAGNETIC RESONANCE IMAGING
• Bone marrow oedema is one of the earliest signs of osteomyelitis
• increase in intramedullary water due to oedema, inflammation
and ischaemia, resulting in areas returning low T1 signal and
increased T2 signal
• If sequestrum is from cortical bone, it has low signal, with a
higher signal if derived from cancellous bone.

18. BRODIES ABSCESS
• In subacute osteomyelitis, an intramedullary
abscess (Brodie’s abscess) may be seen. The central
fluid component has low-to-intermediate T1 signal
and hyperintense T2 signal, surrounded by a
sclerotic rim which has low T1 and T2 signal

19. well-defined lucent lesion with surrounding sclerosis, features of
Brodie’ s intramedullary bone abscess.
(B) SagittalT1-weighted and (C) coronal PD weighted
with fat suppression show the well-defined Brodie’s
abscess with surrounding bone oedema.

20. DIABETIC FOOT – PLAIN RADIOGRAPHY
• Extension of soft-tissue infection into the bone causes osteomyelitis
• The earliest changes include soft-tissue swelling with loss of fat
planes
• classic findings include the triad of osteolysis,periosteal reaction
and bone destruction

21. THE CHANGES PROGRESS TO
destruction of
the cortex.
increased bone
sclerosis due
to sequestrum
formation
loss of blood
supply with
bone necrosis

22. Diabetic foot osteomyelitis. Cortical bone destruction is evident along
the lateral edges of the fifth metatarsal head and base of the adjacent
proximal phalanx, with overlying soft-tissue abnormality due to cutaneous
ulceration

23. MR IN DIABETIC OM
• MR may demonstrate bone marrow oedema, periosteal
reaction, cellulitis, joint effusion, sinus tracts, foot
ulcerations and callus formation and evidence of gangrene

24. complete destruction of distal phalanges and most of
the middle phalanges of the 2nd–4th toes and the
terminal phalanx and bone around the
interphalangeal joint of the
great toe.This ‘sucked candy’ appearance can be due
to chronic neuropathy,

25. images show the presence of bone
marrow oedema, which has lowT1 and
highT2 signal.

26. Images following intravenous contrast medium demonstrate the extent of abscess formation,
confirming active osteomyelitis.

27. TENOSYNOVITIS
• non-compressible thickening of the tendon
sheath
• fluid surrounding the tendon.
• increased colour Doppler flow due to
hyperaemia.

28. non-compressible synovial thickening
synovial thickening and fluid around the
extensor tendons of the hand.There is also
increased colour Doppler flow

29. SEPTIC ARTHRITIS
• sudden onset of monoarticular arthritis, associated with systemic symptoms clinical
signs of a joint effusion.
• Septic arthritis is also twice as common in boys,
• pain and swelling around the joint with reluctance to move the limb.
• Pseudo-paralysis and painful passive movements may be present

30. PLAIN RADIOGRAPHS
• are not diagnostic in early septic arthritis but may reveal signs
suggestive of a joint effusion.
• Subsequent cartilage destruction will result in joint space narrowing,
provided the joint is not held open by an effusion.

31. Plain radiograph demonstrates loss of joint space, marked
reduction in bone density of the femoral head and partial
destruction of the subchondral bone plate in the lateral part of
the femoral head.

32. USG
Septic arthritis in a child. (A) demonstrates
the presence of echogenic fluid in the
prepatellar bursa.
(B)There is increased colour Doppler flow in
the surrounding soft tissues and wall of the
bursa.The finding of an infected bursa should
arouse the possibility of adjacent septic
arthritis

33. CT
• CT will reveal joint effusions, and may show bone erosions, bone
destruction and synovial enhancement.

34. MRI – SEPTIC ARTHRITIS
• abnormal bone marrow signal
• synovial thickening with post contrast enhancement.
• Physeal involvement - low T1 and hyperintense T2 signal
along the growth plate associated with widening of the
growth plate and enhancement on post contrast imaging

35. T1W images show a joint effusion with surrounding enhancement,
enhancing bone marrow oedema and an abscess in the adjacent medial
soft tissues

36. MUSCULOSKELETAL TUBERCULOSIS
• Pathologically chronic granulomas develop
• In the spine this causes rarefaction and destruction of the
vertebral end-plates and infection then spreads to adjacent discs.
• In long bones, tuberculous arthritis – starts in the metaphysis,
which spreads to the epiphysis - to the joint.

37. PLAIN RADIOGRAPHY
Acute infection – not much useful
Bony destruction may also be seen in established cases with joint deformities
extensive bone destruction in the glenoid and humeral
head.This appearance in the humeral head has been termed
‘caries sicca’ (dry rot).

38. well-defined lytic defect in the medial aspect of
the second metatarsal.
no evidence of reactive sclerosis or
periosteal new bone formation,

39. Tuberculosis of bone.- expansive
fusiform lesions of the first and fifth
metacarpals associated with soft-tissue
swelling; there is no evidence of a
periosteal reaction. Such diaphyseal
enlargement secondary to tuberculosis is
known as spina ventosa

40. CT
• CT is more sensitive than plain radiographs to demonstrate
cortical and trabecular bone destruction, and periosteal
reaction.
• CT is generally useful for planning guided interventions—
drainage of abscesses or planning/ guiding bone biopsies.

41. MRI
• MRI can be useful in distinguishing between tuberculous and pyogenic arthritis, but
the features show considerable overlap.
TB SEPTIC
Bony erosion Subchondral edema
Synovial thickening and enhancement Articular cartilage destruction
Thin walled abscess – less
inflammation- cold abscess
Thick walled abscess – prominent
inflammation

42. tuberculous septic arthritis with destruction of the head of the
fifth metacarpal, associated with
abscess formation.There is extension of the abscess into the
subcutaneous tissues with sinus formation

43. FUNGAL INFECTIONS
• the most common being coccidioidomycosis, blastomycosis, actinomycosis,
cryptococcosis, and nocardiosis.
• The infection is usually low grade, with the formation of an abscess and a
draining sinus.
• The lesion may resemble a tuberculous skeletal infection because the
abscess is usually found in cancellous bone with little or no reactive
sclerosis or periosteal response

44. CRYPTOCOCCOSIS OF BONE
demonstrates a destructive osteolytic lesion in
the medial aspect of the humeral head, with
minimal sclerosis and no periosteal reaction—
the typical appearance of a fungal infection.
Aspiration biopsy showed the abscess
to be caused by a cryptococcal infection

45. A) Small punched-out lesion is noted in the
body of the scapula (arrowhead). The
curved arrow points to periosteal reaction
along the medial humeral shaft.
CT section
reveals erosions of the anterior and
posterolateral aspects of the humeral
head. Also apparent are destruction of the
articular surfaces
Coccidioidomycosis of bone.
well-defined soft-tissue abscesses
displaying high signal intensity (arrows).
H, humeral head

46. SYPHILITIC INFECTION
• caused by a spirochete, Treponema pallidum.
• Congenital syphilis is transmitted from mother to fetus,
may manifest as a
-- chronic osteochondritis, periostitis, or osteitis.
• The lesions, which most frequently involve the tibia.

47. • destructive changes are usually seen in the metaphysis at the
junction with the growth plate, producing what is called the
Wimberger sign
• In the later stages of disease, involvement of the tibia results in
a characteristic anterior bowing known as sabershin deformity.

48. (A) demonstrates characteristic
periostitis affecting the femora and
tibiae. destructive changes are
evident in the medullary portion of
the proximal tibiae
infectious process has progressed,
with destruction of the tibial
metaphysis and marked periostitis.
The characteristic erosion of the
medial surface of the proximal
tibial metaphysis is termed the
Wimberger sign

49. SABRE TIBIA

50. • Sequential stages of
involvement of a vertebral
body and disk by an
infectious process

51. Intervertebral disk infection. Lateral radiograph
of the lumbar spine in a 32-year-old man
demonstrates the typical radiographic changes
of disk infection. There is narrowing of the disk
space at L4-5,

52. narrowing of the L5-S1 disk space and suggests some fuzziness of the
adjacent vertebral end plates.
(B) CT section through the disk space clearly shows destructive
changes of the disk and vertebral end plate characteristic of infection.

53. (A)changes of disc infection: narrowing of the disk space and destruction of the
vertebral end plates.
(B) destruction of the disk, a large inflammatory mass extending anteriorly
(arrows), destroying anterior longitudinal ligament and infiltrating
paraspinal soft tissues.
( c ) fragmentation of the posterior aspect of adjacent vertebral bodies and
compression of the thecal sac by a large abscess

54. focal area of decortication of the inferior end plate of L5
(arrows) representing osteomyelitis, with bone marrow edema
of the inferior aspect of the L5 vertebral body and superior
aspect of the S1 vertebral body.

55. • Tuberculosis of the spine may cause collapse of a partially or
completely destroyed vertebra, leading to kyphosis and a
gibbous formation.
• Extension of infection to the adjacent ligaments and soft
tissues is also rather frequent; the psoas muscles are often the
site of secondary tuberculous infections, commonly called cold
abscesses

56. GIBBUS
Gibbus deformity is a short-segment structural
thoracolumbar kyphosis resulting in sharp angulation

57. Tuberculous cold abscess. Anteroposterior
radiograph of the pelvis in a 35-year-old
woman with spinal tuberculosis shows an oval
radiodense mass with spotted calcifications
overlapping the medial part of the ilium and
right sacroiliac joint

58. Tuberculous vertebral osteomyelitis. (A, B) discitis
of L4/5 vertebra extending to superior end-plate of L5
vertebra, extending to the vertebral body.There is also
extension of the abscess into the spinal canal.

59. TUBERCULOUS ‘COLD’ ABSCESS.
(A) MR sagittal and (B) axialT2W sequences demonstrate a
large abscess extending over
the surface of the psoas muscle in the pelvis, arising from
tuberculous discitis at L4/5.

60. • Thank you