Download - Backache imaging presentation
Backache Imaging Presentation
Hieder A`ala601
MUST University
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.
Causes of back pain and sciatica Paraspinal muscles
and ligaments Synovial joints:
Facet and sacroiliac joints
Disc disease Tear of annulus
fibrosis Specific nerve root
impingements
Spondylosis Spinal stenosis Foraminal stenosis
Bone disease Tumor Fracture
Infection Epidural abscess discitis
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?
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?
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.
“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
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
Radiography
AP and lateral films Oblique films Flexion / extension films
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
Discitis
Radiography Diagnosis
best made on oblique films: Spondylolysis Facet arthritis Foraminal
stenosis (cervical spine)
Facet joints
Radiography Diagnosis made with flexion /
extension films: instability
Spondylolysis Stress fracture through pars
interarticularis If bilateral, can cause spondylolisthesis
spondylolisthesis
spondylolysisSagittal reformatted CT
Cross Sectional Imaging: CT and MRIWhy?
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
Anatomy (see hieder lecture on radiological anatomy )
T1 T2
Conus medullaris
Cauda equina
Anatomy
disc
Nerve root in foramen
Nucleus pulposis
Nerve root in foramen
Facet jointLigamentum
flavum
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.
Intervertebral disc anatomy
Annular fibers
Nucleus pulposus
T2
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
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
Glossary of disc pathology terms
Localizing terms: Central Paracentral Foraminal Lateral
Annular disc bulge
Disc bulges diffusely
Broad based disc protrusion
IM: 6 SE: 201IM: 6 SE: 201Compressed 7 :1Compressed 7 :1
cm cmIM: 6 SE: 301IM: 6 SE: 301
Compressed 7 :1Compressed 7 :1
cm cm
cm cm
cm cm
Paramedian disc protrusion
Normal right L5 root Displaced left L5 root
This should correlate with a left L5 radiculopathy.
Right paramedian disc protrusion
Axial T2Sag T1 Sag T2
Foraminal Disc Extrusion
Foraminal Fat Obliterated
Normal foramina
Even large disc extrusions will resolve spontaneously
Several months laterLarge extruded disc
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
Spaces for nerve roots
cm cm
Nerve root in lateral recessNeural foramen
Cauda equina roots in spinal canal
Facet joint arthritis
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
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
Spondylosis (Degenerative
Disease)
Sag T2 Axial T2 Axial CT
Annular disc bulge and facet arthropathy cause spinal stenosis
Spondylosis causing spinal stenosis
Page: 6 of 11Page: 6 of 11 IM: 6 SE: 3IM: 6 SE: 3Compressed 5 :1Compressed 5 :1
cm cm
Page: 8 of 18Page: 8 of 18 IM: 8 SE: 5IM: 8 SE: 5Compressed 5 :1Compressed 5 :1
cm cm
Page: 11 of 18Page: 11 of 18 IM: 11 SE: 5IM: 11 SE: 5Compressed 5 :1Compressed 5 :1
cm cm
Page: 13 of 18Page: 13 of 18 IM: 13 SE: 5IM: 13 SE: 5Compressed 5 :1Compressed 5 :1
cm cm
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.
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?
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
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
Bacterial discitis
T1 SagT1 Axial With GD
T2 Sag
Tuberculous spondylitis with epidural abscess
T1 with Gd T2
Enhancing vertebral body
Non-enhancing fluid in disc space and epidural space
IV drug user– paraspinal abscess
T1 unenhanced T1 enhanced
T2 unenhanced
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
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
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
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
Thank you