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