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
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.
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
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.
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
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
