This document discusses diabetic musculoskeletal complications and their imaging mimics. It covers several topics: 1. Muscle disorders in diabetes including diabetic muscle ischemia, infectious myositis, inflammatory myopathies like polymyositis, muscle denervation, and other disorders like deep vein thrombosis. 2. Pedal disorders like osteomyelitis, neuropathic osteoarthropathy, and infected neuropathic osteoarthropathy. 3. Spinal disorders including dialysis-associated spondyloarthropathy, pyogenic spondylodiskitis, and neuropathic spine. For each topic, the document discusses pathogenesis, clinical presentation, and MRI imaging features to help differentiate these complications from other disorders. Differential

1. Diabetic Musculoskeletal
Complications and Their Imaging
Mimics
Dr. Mohit Goel
JR II, 28th march
2014
RadioGraphics,
http://pubs.rsna.org/doi/abs/10.1148/rg.327125054
Published in: Jonathan C. Baker; Jennifer L. Demertzis; Nicholas G. Rhodes; Daniel E.
Wessell; David A. Rubin; RadioGraphics 2012, 32, 1959-1974.
DOI: 10.1148/rg.327125054
© RSNA, 2012

2. Muscle Disorders in Diabetes
Pedal Disorders in Diabetes
Spinal Disorders in Diabetes
Diabetic Musculoskeletal Complications

3. Muscle Disorders in Diabetes
1. Diabetic Muscle Ischemia
2. Infectious and Inflammatory Myositis
3. Muscle Denervation
4. Other Muscle Disorders

4. Pedal Disorders in Diabetes
1. Osteomyelitis
2. Neuropathic Osteoarthropathy
3. Infected Neuropathic Osteoarthropathy

5. Spinal Disorders in Diabetes
1. Dialysis-associated Spondyloarthropathy
2. Pyogenic Spondylodiskitis
3. Neuropathic Spine

6. Muscle Disorders in Diabetes
Diabetic Muscle Ischemia
DMI, also referred to as diabetic muscle infarction or diabetic
myonecrosis, characteristically occurs in patients with long-
standing, poorly controlled diabetes.
Pathology: muscle fiber necrosis and edema are seen in
association with fibrinous occlusion of arterioles and capillaries
The clinical onset of DMI is abrupt, with severe thigh or calf pain
and swelling that evolve over days or weeks, in the absence of
leukocytosis and fever.

7. MR imaging features of DMI include muscle enlargement, muscle
edema, and fascial.
Muscle enhancement is seen, often with central regions of
hypoenhancement or nonenhancement.
The findings may be unilateral or bilateral and often are seen in
noncontiguous muscles in the thighs and calves

8. DMI in a 40-year-old man with poorly controlled diabetes who presented after
several weeks of severe right thigh pain and swelling.
T1WI
FATSAT
T2WI
FATSAT

9. Contrast enhanced
T1-weighted fat-
suppressed
Subtraction
MR images

10. Infectious Myositis
Because of underlying immune dysfunction, diabetic patients are
vulnerable to infectious pyomyositis, a disease that results from the
hematogenous spread of bacteria to muscle.
This entity is an important differential diagnostic consideration in
patients in whom the presence of DMI is suspected.
Although the imaging appearances of the two entities may overlap,
imaging features favoring the diagnosis of pyomyositis over that of
DMI include the presence of smooth-walled intramuscular
abscesses with rimlike enhancement.

11. By contrast, areas of muscle ischemia or necrosis in DMI tend to
appear heterogeneous, with linear streaks of enhancement crossing
central nonenhancing regions surrounded by extensive regions of
enhancing muscle.
Clinical features favoring the diagnosis of infectious pyomyositis
over that of DMI include fever, leukocytosis with a left shift,
elevated inflammatory markers, and bacteremia.
The distinction between DMI and pyomyositis is important, because
the latter requires antibiotic therapy and abscess drainage.

12. Infectious pyomyositis in a 58-year-old man with tense and reddened calves,
leukocytosis, and an elevated ESR.
T2-weighted fat-suppressed MR image
Contrast-enhanced T1-weighted MR image

13. Inflammatory Myositis
Unlike DMI, inflammatory myopathies such as dermatomyositis,
polymyositis, and inclusion body myositis usually manifest with
insidious, gradually progressive proximal muscle weakness.
MR imaging findings of bilateral symmetric edema in the proximal
muscles, particularly those in the pelvis and thighs, are helpful for
identifying inflammatory myopathy and determining its severity.
The diagnosis is based on clinical history, physical examination,
muscle enzyme testing, and muscle biopsy with immunostaining.

14. Polymyositis in a 55-year-old woman with weakness of the proximal thigh muscles.
T1-weighted MR image
T2-weighted MR image

15. Muscle Denervation
Muscle denervation has a multiple etiology, with diabetic peripheral
neuropathy being one of the most common causes.
Subacute muscle denervation is characterized by T2 signal
hyperintensity in the affected muscles, which maintain their normal
signal intensity and architecture on T1-weighted images.
In contrast, muscles affected by chronic denervation have reduced
bulk and show evidence of fatty infiltration, which is best depicted
on T1-weighted images.

16. Subacute or chronic denervation manifests early and prominently
in diabetic patients, usually affecting the intrinsic musculature of
the foot.
Involvement of muscles within a peripheral nerve distribution,
lack of associated fascial edema, and presence of peripheral
neuropathy at physical examination help distinguish denervation
due to diabetic peripheral neuropathy from that caused by DMI.

17. Subacute-on-chronic muscle denervation in a 58-year-old diabetic woman.
T1WI
T2WI

18. Other Muscle Disorders
Unilateral or bilateral pain and swelling of the thighs and calves also
may result from deep vein thrombosis.
Because the clinical symptoms of DVT are nonspecific, the condition
is often detected incidentally at MR imaging of the lower extremity.
The MR imaging manifestations of DVT are similar to those of DMI
and include edema of deep muscle and fascia on images obtained
with fluid-sensitive sequences.
However, the presence of branching, tubular structures with
peripheral enhancement and the involvement of contiguous
muscles within the distribution of a draining vein help identify deep
vein thrombosis.

19. Deep venous thrombosis mimicking DMI in a 47-year-old man with rapidly developing left
calf pain and swelling.
T2 FATSAT
T1 FATSAT

20. Pedal Disorders in Diabetes
Osteomyelitis
Diabetic pedal osteomyelitis almost invariably results from an ulcer
or abscess in contiguous soft tissue. Ulcers tend to occur in the
anatomic sites that are subjected to the highest contact pressures
during ambulation.
The development of classic radiographic features of osteomyelitis,
including periostitis and bone destruction, may lag behind the
clinical manifestations by 10–20 days, and radiography is relatively
insensitive to small amounts of bone destruction.

21. For these reasons, if the findings at initial radiography are
inconclusive and the clinical suspicion persists that diabetic pedal
osteomyelitis is present, the Infectious Diseases Society of America
recommends that radiography be repeated 2–4 weeks later.
The most important finding for a diagnosis of diabetic pedal
osteomyelitis is bone marrow edema immediately adjacent to a soft-
tissue infection or ulcer, with or without evidence of cortical
destruction

22. Calcaneal osteomyelitis with necrotic soft tissue in the right heel of a 75-year-old diabetic man.
T1WI FAT SAT
T2WI FAT SAT

23. POST CONTRAST T1
FAST SAT

24. Neuropathic Osteoarthropathy
Although its pathogenesis is not completely understood, it has been
suggested that repetitive trauma to insensate joints and autonomic
dysfunction of blood flow result in bone hyperemia, resorption, and
weakening.
Localized inflammation then leads to bone destruction, joint
subluxation and dislocation, and foot deformity.
In the setting of acute neuropathic osteoarthropathy, MRI shows
extensive soft-tissue edema occurring in the absence of infection or
ulceration.
Multiple foci of marrow edema are seen on both T1WI and fluid-
sensitive MR images in the affected bones.

25. Prominent subchondral edema and enhancement may extend far
into the medullary cavity, although superimposed fractures also
can contribute to changes in marrow signal intensity.
Subchondral cyst formation, articular erosions, and joint effusions
are common, with periarticular enhancement occurring after the
administration of intravenous contrast material.

26. Acute neuropathic osteoarthropathy initially misdiagnosed clinically as pedal osteomyelitis in a
46-year-old diabetic man.

27. T1
FATSAT
Post contrast

28. Chronic neuropathic osteoarthropathy has a less inflammatory
appearance, with less visible swelling and less marked edema and
enhancement at MR imaging.
The bones may appear sclerotic at radiography, and they have low
marrow signal intensity at MR imaging regardless of the pulse
sequence used.
Subchondral cysts are well defined, and proliferative bone may be
seen with debris, intraarticular bodies, and ankylosis. Joint
subluxation or dislocation is common due to subchondral collapse,
with resultant articular instability in later stages of the disease
process.

29. Chronic neuropathic osteoarthropathy in a 49-year-old diabetic woman

30. Spinal Disorders in Diabetes
Dialysis-associated Spondyloarthropathy
The disorder was attributed to amyloid (β2-microglobulin)
deposition in synovium, intervertebral disks, and other connective
tissues.
Amyloid deposition may occur in both appendicular and axial
skeletal structures; in the axial skeleton, it develops
predominantly in the lower cervical spine
Characteristics of dialysis-associated spondyloarthropathy include
intervertebral disk space loss, extensive vertebral endplate
erosion and cyst formation, and minimal formation of endplate
spurs.

31. Dialysis-associated spondyloarthropathy in a 55-year-old man.

32. T1W FATSAT T2W FATSAT

33. Infectious spondylodiskitis, ankylosing spondylitis, and
degenerative disk disease are important differential diagnostic
considerations.
Clinical features including the absence of a fever and the presence
of a normal ESR and normal WBC count also favor the diagnosis of
dialysis-associated spondyloarthropathy over that of infectious
diskitis.
Although degenerative disk disease also results in disk space
narrowing and changes in the signal intensity of subchondral bone
marrow, the endplate erosions with minimal osteophytosis that
are found in dialysis-associated spondyloarthropathy are not
expected to be present in degenerative disk disease.

34. Pyogenic Spondylodiskitis
Classic imaging findings include a narrowed disk space with
destruction of the neighboring vertebral endplates.
Spine infection usually begins in the anterior aspect of the vertebral
body because of its rich blood supply and subsequently extends
through the disk to neighboring vertebral bodies.
MRI shows decreased T1 signal intensity and increased T2 signal
intensity in the affected vertebral endplates and disk.
Post contrast images at an early stage of the disease process include
enhancement of the disk and along the vertebral endplates; at a later
stage, enhancement is accompanied by progressive destruction of
the vertebral body.

35. Pyogenic spondylodiskitis in a 54-year-old diabetic man.
T1W FATSAT T2W FATSAT

36. Contrast-enhanced T1-weighted fat-suppressed

37. MRI features favoring pyogenic spondylodiskitis over dialysis-
associated spondyloarthropathy include the presence of intradiskal
fluidlike signal intensity and enhancement, both of which are
uncommon in the latter condition.
A finding of paraspinal or epidural abscess also supports a diagnosis
of infectious spondylodiskitis.

38. Similarly, MR imaging features can help distinguish spondylodiskitis
from degenerative disk disease.
In degenerative disk disease with Modic type 1 endplate changes
are seen; the disk and endplates may also demonstrate
enhancement; however, fluidlike signal intensity is generally lacking
from the disk in the setting of degenerative disease, and a
paravertebral phlegmon or fluid collection would be an unusual
finding.
The presence of gas in the disk space is also suggestive of a
degenerative process.

39. Neuropathic Spine
Diabetes mellitus is now the most common cause of neuropathic
disease of the spine.
The neuropathic spine (Charcot spine) displays intervertebral
space narrowing, vertebral osteolysis and osteosclerosis,
subluxations, abrupt curvature, and large endplate spurs.

40. Neuropathic spine in a 64-year-old man.

41. T2W FATSAT Contrast-enhanced T1 FATSAT

42. Several features help distinguish neuropathic spinal arthropathy
from spinal infection:
Observations of the disk vacuum phenomenon and facet
involvement favor the diagnosis of neuropathic arthropathy over
that of infection.
Spondylolisthesis and bone fragmentation also are seen primarily in
neuropathic spinal arthropathy and not infection.
Finally, rimlike enhancement of the disk and marrow signal intensity
changes throughout the vertebral body favor the diagnosis of
arthropathy, whereas diffuse enhancement of the disk with marrow
signal abnormalities confined to the vertebral body endplates
support the diagnosis of infection.

43. THANK YOU