Presented by: Dr David Lisle — Radiologist Event: GP Education Day - 2013

1. Appropriate imaging for
back pain
Dr David Lisle
Brisbane Private Imaging
Royal Brisbane Hospital
University of Queensland

2. Appropriate imaging for back pain
• Imaging modalities
• Clinical presentations
• Guidelines

3. Appropriate imaging for back pain
• Imaging modalities
– Radiographs (X-rays)
– Scintigraphy (bone scan)
– CT
– MRI
• Clinical presentations
• Guidelines

4. Radiographs
What you see
• Bony anatomy and
alignment
• Disc height

5. Radiographs
What you see
• Bony anatomy and
alignment
• Disc height
Disadvantages
• Radiation
• Nonspecific
– OA changes in most
adults
• Insensitive
– No direct visualisation
of neural and other
nonbony structures

6. Bone scan
What you see
• Bone pathology
– Osteoblastic activity

7. Bone scan
What you see
• Bone pathology
– Osteoblastic activity
Disadvantages
• Radiation
• Very nonspecific
• Relatively poor
anatomical resolution
– (Improved with
SPECT; SPECT/CT)
– No direct visualisation
of neural and other
nonbony structures

8. CT
What you see
• Bony anatomy and
alignment
• Cross sectional view
of spinal canal and
foramina
• Disc, thecal sac,
nerve roots

9. CT
What you see
• Bony anatomy and
alignment
• Cross sectional view
of spinal canal and
foramina
• Disc, thecal sac,
nerve roots
Disadvantages
• Radiation
• Nonspecific
– Most adults have
‘findings’
• Poor visualisation of
individual neural
structures and disc
anatomy

10. Radiation doses
Imaging test Effective
dose (mSv)
CXRs Background
exposure
Flying hours
CXR 0.02 1 3 days 4
Lumbar X-ray 1.5 75 6/12 300
Lumbar CT 2-10 100-500 8/12 - 3 years 400 - 1800
Bone scan 6 300 2 years 1200

11. MRI
What you see
• Bony anatomy and
alignment
• Bone pathology
• Multiplanar view of
spinal canal and
foramina
• Disc: hydration and
structure
• Neural structures:
cord, nerve roots

12. MRI
What you see
• Bony anatomy and
alignment
• Bone pathology
• Multiplanar view of
spinal canal and
foramina
• Disc: hydration and
structure
• Neural structures:
cord, nerve roots
Disadvantages
• Availability, cost
• Pacemakers,
claustrophobia
• Nonspecific (too
sensitive)
– Most adults have
‘findings’

13. Appropriate imaging for back pain
• Imaging modalities
• Clinical presentations: classification into 3
broad categories
1. Nonspecific low back pain
2. Back pain associated with radiculopathy
3. Back pain associated with a specific
cause requiring prompt evaluation
• Guidelines

14. Back pain categories
1. Nonspecific (mechanical) low back pain
– Acute: < 12 weeks
– Chronic: > 12 weeks
– Ligament/ muscle strain/ tear
– Intervertebral disc degeneration
– Osteoarthritis
– Facet joints
– SI joints
– Spondylolysis/ spondylolisthesis

15. Back pain categories
2. Back pain associated with radiculopathy
a) Unilateral acute nerve root compression
(sciatica)
– Leg pain >> back pain
– Disc herniation
b) Unilateral chronic nerve root compression
– Disc herniation or spinal stenosis
c) Bilateral chronic nerve root compression
– Spinal stenosis
– DD vascular claudication
d) Bilateral acute nerve root compression =
‘cauda equina syndrome’

16. Cauda equina syndrome
• Bilateral acute nerve root compression
– Massive disc protrusion/ sequestration
• Sudden onset bilateral leg pain
• Saddle anaesthesia
• Rapidly progressive or severe neurological
deficits
– Motor deficits at >1 level
– Faecal incontinence
– Urinary retention

17. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Cauda equina syndrome
− Cancer
− Vertebral infection
− Vertebral compression fracture
− Ankylosing spondylitis

18. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Cauda equina syndrome
− Clinical scenario
− Cancer
− Vertebral infection
− Vertebral compression fracture
− Ankylosing spondylitis

19. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Cancer
− Hx of Ca + new onset LBP
− Unexplained weight loss +/-
persistent symptoms +/- age > 50
− Vertebral infection
− Vertebral compression fracture
− Ankylosing spondylitis

20. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Vertebral infection
− Fever
− iv drug use
− Recent infection
− Vertebral compression fracture
− Ankylosing spondylitis

21. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Vertebral compression fracture
− Hx of osteoporosis
− Steroid use
− Old age +/- minor trauma
− Ankylosing spondylitis

22. Back pain categories
3. Back pain associated with a specific
cause requiring prompt evaluation
− Ankylosing spondylitis (seronegative
SpA)
− Nonmechanical, inflammatory type of
back pain: morning stiffness; improved
with exercise
− Alternating buttock pain
− Waking at night
− Younger age

23. Appropriate imaging for back pain
• Imaging modalities
• Clinical presentations
• Guidelines
– Multiple: different countries and
associations
– Common theme:
• Triage into 3 broad categories as
described

24. LOW BACK PAIN GUIDELINES
Diagnostic triage
1. Non-specific LBP
2. Radiculopathy
3. Specific LBP
• ‘Red flags’
‘Red Flags’
• Cauda equina syndrome
• Known 10 tumour
• Weight loss
• Severe symptoms, not
settling
• Fever
• Recent infection or Sx
• Osteoporosis
• Steroid use
• Non-mechanical pain
• Child*

25. Back pain in children and adolescents
Presentation Associated Sx DD Ix
Night pain Fever, malaise Tumour, infection X-ray
MRI
Acute pain Radiculopathy
+ve SLR
Disc herniation
Spondylosis
X-ray
MRI
Chronic pain Rigid kyphosis
Morning stiffness
“Scheuermann’s”
Inflammatory arthropathy
X-ray
Pain with extension
Sport: eg rowing
Hamstring tightness Spondylolysis
‘Stress reaction’
X-ray
MRI
Pain + recent onset
scoliosis
Fever, malaise,
+ve SLR
Idiopathic scoliosis
Tumour, infection, syrinx,
disc herniation
X-ray
MRI
Am Fam Phys 2007;76:1669-76

26. LOW BACK PAIN GUIDELINES
• American College of Physicians & American
Pain Society Recommendations
1. Focused Hx and examination to place patients
into 1 of 3 categories
2. No imaging for nonspecific LBP
3. Imaging for LBP + severe or progressive
neurological deficits OR risk factors for specific
cause
4. Imaging for LBP and radiculopathy if candidates
for surgery or epidural injection
Ann Intern Med 2007;147:478-491

27. Diagnostic work-up
Possible cause Imaging Additional studies
Nonspecific LBP None None
Radiculopathy MRI (CT)
Cauda equina MRI
Cancer MRI for known 10; X-ray
for other eg wt loss
ESR
Vertebral infection MRI ESR, CRP
Vertebral compression # X-ray
Ankylosing spondylitis X-ray, incl pelvis (MRI) HLA-B27; ESR, CRP
Ann Intern Med 2007;147:478-491

28. www.imagingpathways.health.wa.gov.au
National Institute for Clinical Excellence
(NICE) UK
ACR Appropriateness Criteria

29. Ineffectiveness of imaging for
nonspecific LBP
• Favourable natural Hx
– Most improve by 4 weeks; unaffected by imaging
• Nonspecificity: loose association between findings
and symptoms
– ‘Abnormalities’ or normal aging?
• Potential harms:
– Radiation
– ‘Labelling’
– Incidental findings
Ann Intern Med 2011;154:181-190

31. • 85 year old female
• Severe acute on chronic mechanical
back pain
– Can’t sleep
– Limited walking to only a few steps
• Spontaneous onset
• No known trauma
Radiograph (X-ray)

33. 24/3/2012

34. 24/3/2012 16/12/2011

35. MRI: pre-vertebroplasty
STIR

36. 2
3
2
3
T1 STIR

38. • 68M
• Sudden onset bilateral leg pain and
weakness
• Urinary retention
MRI

41. • Dx: Cauda equina syndrome
• Cause: massive sequestration
• Other causes:
– Tumour
• Primary of lower cord, nerve, dura, vertebral
body
• Secondary
– Trauma

42. Cauda equina syndrome
30M 60F 70M
T2

44. • 62 year old male
• Severe low back pain of rapid onset
• Febrile and unwell
• 4 weeks ago underwent abdominal
surgery for perforated diverticulitis
MRI

45. T2 T1 T1FS con

46. T2 T1FS con

47. Thank you