1. Backache Imaging Presentation
Hieder A`ala
601
MUST University

2. Wasted time?
 Radiology departments do lots of imaging
for low back pain.
 X-rays, CT, MRI etc.
 How much makes a difference?
 Studies show advanced imaging in acute
back pain and sciatica doesn’t change
outcomes, but improves diagnostic
confidence.

3. Causes of back pain and
sciatica
 Paraspinal muscles  Spondylosis
and ligaments  Spinal stenosis
 Synovial joints:  Foraminal stenosis
 Facet and sacroiliac  Bone disease
joints  Tumor
 Disc disease  Fracture
 Tear of annulus  Infection
fibrosis  Epidural abscess
 Specific nerve root  discitis
impingements

4. Acute Back Pain
 2nd most common complaint to primary
care physician
 >75% of adults will suffer it at some
time.
 90% will resolve without intervention (or
imaging), most without a specific dx.
 Among patients with sciatica, only
<10% will need surgery.
 Whom to image?

5. Back pain imaging — false
positives
 Most adults over 40 will have
degenerative changes on x-rays
 MRI shows disc pathology in the majority
of adults
 Many asymptomatic people have disc
bulges and protrusions.
 So, imaging is likely to result in an
abnormal report.
 But correlation between radiographic
findings and clinical symptoms is poor.
 When to image?

6. When to image in patients with
acute back pain?
 Most authorities suggest conservative
treatment for 4-6 weeks unless there are
“red flags”:
 Look for historical and physical findings that
raise clinical question of infection, tumor, or
serious neurological impairment
 Even positive findings of degenerative
disease like disc extrusions and spinal
stenosis are not urgent and will be treated
conservatively at first.

7. “Red flags” for early imaging
 Severe progressive neurological deficit
 Fracture?
 Major trauma or minor trauma in osteoporotic pt.
 Tumor?
 History of cancer, weight loss
 Pain worse at night or when supine
 Infection?
 Recent bacterial infection, immune supression,
fever, IVDA

8. Imaging options
 Radiography
 CT
 Better for fine bone detail, arthritis
 As good as MRI for acute disc disease
 Myelography as adjunct
 MRI
 Very good for disc, paraspinal pathology, stenosis
 Infection
 Marrow disorders
 Contrast for infection, post-op, tumor
 Bone scan
 Not for primary imaging in most cases
 Discography

9. Radiography
 AP and lateral films
 Oblique films
 Flexion / extension films

10. Radiography
 Diagnoses that can be made on AP and
lateral:
 Spondylolisthesis
 Compression fracture
 SI joint disease
 Disc degeneration
 Facet arthritis
 Tumor
 Infection in disc space

11. Discitis

12. Radiography
 Diagnosis
best made on
oblique films:
 Spondylolysis
Facet joints
 Facet arthritis
 Foraminal
stenosis
(cervical
spine)

13. Radiography
 Diagnosis made with flexion / extension
films:
 instability

14. Spondylolysis
 Stress fracture through pars interarticularis
 If bilateral, can cause spondylolisthesis
Sagittal reformatted CT spondylolysis
spondylolisthesis

15. Cross Sectional Imaging: CT and MRI
Why?
 Confirm extent of degenerative disease and
spinal stenosis.
 Search for confirmatory findings in patient with a
specific radiculopathy if surgery is
contemplated.
 Occult back pain not responding to conservative
treatment
 Rule out tumor or infection in appropriate
patients

16. Anatomy (
see hieder lecture on radiological anatomy )
T1 T2
Conus
medullaris
Cauda
equina

17. Anatomy
Nucleus
pulposis
Nerve root Nerve root
in foramen in foramen
disc
Facet joint
Ligamentum
flavum

18. Disc disease
 After age 40, most adults have at least
some desiccation and loss of height of
lumber discs:
 Low signal on T2 images.
 Posterior or diffuse bulges and protrusions
are common.
 Jelly-like nuclear material leaks out through
tear in annular fibers.

19. Intervertebral disc anatomy
Nucleus
pulposus
Annular fibers
T2

20. Glossary of disc pathology
terms
 Herniation: nonspecific term subject to
misinterpretation.
 Not recommended.
 Bulge: diffuse enlargement of disc area
 Very common
 Usually not clinically important
 May contribute to spinal stenosis
 Protrusion: nucleus pulposus pushes focally
through fibers of annulus fibrosis
 Base wider than apex
 May focally impinge on nerve or thecal sac

21. Glossary of disc pathology
terms
 Extrusion: nucleus material pushes out
beyond posterior longitudinal ligament but
remains in contact with disc space
 Apex wider than base
 Likely to impinge on nerve roots
 Sequestration: Disc fragment isolated from
parent disc

22. Glossary of disc pathology
terms
 Localizing terms:
 Central
 Paracentral
 Foraminal
 Lateral

23. Annular disc bulge
Compressed 8 :1
Disc bulges diffusely
Page: 54 of 100 IM: 54 SE: 3

24. Broad based disc protrusion
Compre
Page: 2 of 18 IM:
cm
cm
Compressed 7 :1 Compressed 7 :1
Compressed
f 11 Page: 6IM:11SE: 201
of 6 IM: 6 SE: 301
cm
cm cm
cm

25. Paramedian disc protrusion
Normal right L5 root Displaced left L5 root
This should correlate with a left
L5 radiculopathy.

26. Right paramedian disc protrusion
Sag T1 Sag T2 Axial T2

27. Foraminal Disc Extrusion
Normal
foramina
Foraminal Fat Obliterated

28. Even large disc extrusions will
resolve spontaneously
Large extruded disc Several months later

29. Spondylosis
 Degenerative disease
 Disc desiccation, bulges and protrusions
 Ligamentum flavum hypertrophy
 Facet arthritis and hypertrophy
 Degenerative spondylolisthesis (seen in 7% of
asx patients)
 Osteophytes
 All combine to cause stenosis of spaces that
nerve roots pass through:
 Canal, lateral recess, neural foramen

30. Spaces for nerve roots
Cauda equina roots in spinal canal
Neural foramen Nerve root in lateral recess
Compr
Comp
Page: 13 of 18 IM
cm
cm

31. Facet joint arthritis

32. Spinal stenosis
 Symptoms
 Neurogenic claudication
 Pain relieved with sitting, bending forward
 Progressive pain
 +/- radiculopathy, cauda equina syndrome
 +/- low back pain
 No specific measurement to define it in the
lumber spine.
 Many improved with nonsurgical therapy

33. Spinal stenosis
 Contributing factors:
 Disc bulges and protrusions
 Facet arthropathy
 Ligamentum flavum hypertrophy
 Posterior vertebral body osteophytes

Anterior and lateral osteophytes generally not
important
 Spondylolisthesis

Not spondylolysis alone

34. Spondylosis
(Degenerative Disease)
Sag T2 Axial T2 Axial CT
Annular disc bulge and facet arthropathy cause
spinal stenosis

35. Spondylosis causing spinal
stenosis
Compressed 5 :1
Compressed 5 :1 Page: 11 of 18 IM: 11 SE: 5
cm
cm
Page : 8 of 18
18 IM: 8 SE: 5
cm
cm
Compressed 5 :1
Page: 6 of 11 IM: 6 SE: 3
cm
cm
Compressed 5 :1
Page: 13 of 18
13 IM: 13 SE: 5
cm

36. What does that report mean?
 Facet disease:
 Common in older patients
 May cause pain radiating to hip, simulating
sciatica
 Predisposes to dynamic instability
 Contributes to spinal and foraminal stenosis
 Mild disc bulges or protrusions
 Very common incidental findings
 Focal sciatica
 Spinal stenosis only if large or in combination
with other factors (formerly asx stenosed canal)
 Usually not significant unless good correlation
with sx.

37. What does that report mean?
 Look for key words and descriptions:
 “spinal stenosis”, “foraminal stenosis”
 Nerve root “displacement”, “compression” or
“impingement” (see lecture of nomenclature)
 Is a specific root involved?
 Does it correlate with symptoms?

38. What to order: MRI or CT
 MRI generally preferred
 Contraindications to MRI? — CT is an
acceptable substitute for disc and bony
disease, but poor for infection or
intrathecal tumor.
 MRI — IV contrast only for:
 Suspected infection
 Suspected tumor
 Post-operative spine

Recurrent disc vs. scar tissue

39. Spinal and Epidural Infection
 High risk populations:
 Immunocompromised

AIDS

Transplant

Chemotherapy
 Endocarditis or sepsis
 Postoperative patients especially with
hardware (instrumentations)
 Tuberculosis: not necessarily immune
compromised

40. Bacterial discitis
T1 Axial With GD
T1 Sag T2 Sag

41. Tuberculous spondylitis with
epidural abscess
Enhancing
vertebral body
Non-enhancing
fluid in disc
space and
epidural space
T1 with Gd T2

42. IV drug user– paraspinal
abscess
T1 unenhanced T1 enhanced
T2 unenhanced

43. Compression fracture:
Benign or malignant?
 Often difficult to distinguish cause of
acute compression fracture
 History of osteoporosis?
 Osteoporosis may indicate multiple myeloma in
patient without risk factors.
 History of primary tumor?
 MRI good for survey of marrow at other
levels to look for other metastases
 Bone scan may serve same function

44. Compression fracture:
Acute or chronic?
 Many patients have unsuspected old
compression fractures:
 Cheapest evaluation: check old films!
 Bone scan can prove a fracture is old
 May remain positive for up to two years
 In elderly, may not be positive in first day
 MRI can detect acute marrow edema

45. Compression Fracture—new or
old?
• New
• Hypointense T1
• Hyperintense T2
Easily missed if only T2
Sequence used
• Chronic
• Same marrow
signal as other
vertebral bodies on
all pulse
sequences T1 T2

46. Metastatic disease
 On T1 weighted
images, discs should
be darker than
marrow tissue
 Tumor brighter on T2
weighted images,
enhances with
contrast
 Exception—sclerotic
prostate metastases

47. Thank you