Appropriate imaging for back pain Dr David Lisle Brisbane Private Imaging Royal Brisbane Hospital University of Queensland
Appropriate imaging for back pain
Dr David Lisle
Brisbane Private Imaging Royal Brisbane Hospital University of Queensland
Appropriate imaging for back pain
• Imaging modalities • Clinical presentations • Guidelines
Appropriate imaging for back pain
• Imaging modalities – Radiographs (X-rays) – Scintigraphy (bone scan) – CT – MRI
• Clinical presentations • Guidelines
Radiographs
What you see
• Bony anatomy and alignment
• Disc height
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
Bone scan
What you see
• Bone pathology – Osteoblastic activity
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
CT
What you see
• Bony anatomy and alignment
• Cross sectional view of spinal canal and foramina
• Disc, thecal sac, nerve roots
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
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
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
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’
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
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
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’
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
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
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
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
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
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
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
Appropriate imaging for back pain
• Imaging modalities • Clinical presentations • Guidelines
– Multiple: different countries and associations
– Common theme: • Triage into 3 broad categories as
described
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*
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
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
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
www.imagingpathways.health.wa.gov.au
National Institute for Clinical Excellence (NICE) UK ACR Appropriateness Criteria
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
• 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)
24/3/2012
24/3/2012 16/12/2011
MRI: pre-vertebroplasty
STIR
2
3
2
3
T1 STIR
• 68M • Sudden onset bilateral leg pain and
weakness • Urinary retention
MRI
• Dx: Cauda equina syndrome • Cause: massive sequestration • Other causes:
– Tumour • Primary of lower cord, nerve, dura, vertebral
body • Secondary
– Trauma
Cauda equina syndrome
30M 60F 70M
T2
• 62 year old male • Severe low back pain of rapid onset • Febrile and unwell • 4 weeks ago underwent abdominal
surgery for perforated diverticulitis
MRI
T2 T1 T1FS con
T2 T1FS con
Thank you