Chapter 9 - Spine Imaging Flashcards
This results from compromise of the spinal cord itself, due to mechanical compression, intrinsic lesions, or inflammatory processes grouped under the term “myelitis”.
Myelopathy
Classic symptoms include bladder and bowel incontinence, spasticity, weakness, and ataxia.
With cord compression, a clear motor or sensory spinal cord “level” may develop.
Myelopathy
This is due to impingement or irritation of the spinal nerves within the spinal canal, lateral recess, neural foramen, or along the extraforaminal course of the nerve.
Radiculopathy
Most common causes of radiculopathy
- Disc herniations
- Spinal stenosis
- Uncovertebral joint spurring
This was once the initial test in every spine evaluation, but this is no longer logical or cost effective.
It continue to be useful for ruling out trauma to the vertebral column and other acute screening settings.
Conventional radiography.
This is almost always done in conjuction with CT.
Indications include complex postoperative cases and patients in who MR is contraindicated due to incompatible implanted devices.
Myelography
Contrast agents that are absolutely contraindicated for myelography, as they result in severe inflammation, seizures, arachnoiditis and even death.
Ionic contrast agents
Recommended dosage of nonionic contrast in adults depends on the region to be studied, the size of the patiet, and the size of thecal sac.
What is the convenient and conservative rule of thumb in adults?
Not to exceed 3 g of intrathecal iodine.
17 ml of 180 mg/mL
12.5 mL of 240 mg/mL
or
10 mL of 300 mg/mL
The three standard concentrations.
This has been replaced by MR for most screening examinations of the spine, except for acute trauma.
Computed Tomography
This is the most common spinal cord “inflammatory” disorder, and by far the most frequent cause of intramedullary lesion seen on MR.
Multiple sclerosis (MS)
Best screening protocol of MS
Sagittal T2W or inversion recovery sequences -
Where MS plaques appear as areas of increased signal intensity.
Location of MS plaques in the spinal cord
Since the white matter is on the outside of the cord.
MS plaues tend to be PERIPHERAL.
This is an autoimmune disorder affecting the spinal cord and optic nerves.
The spinal cord lesions are longer than MS, and the brain is often spared.
Devic disease, or neuromyelitis optica (NMO)
A CNS inflammatory process in which a necrotizing arteririts leads to cord ischemia and injury.
Antibodies damages neuronal elements directly.
Systemic lupus erythematosus (SLE)
Imaging finding of SLE of the spinal cord.
The spinal cord will show diffuse areas of increased signal intensity with cord swelling on T2WI.
SLE “lesions” have less well-defined margins than the discrete plaques of MS and may involve the cord over 4 to 5 vertebral body segments.
How does rheumatoid arthritis cause spinal cord injury?
Focal inflammatory change termed “pannus” destroys the transverse ligament of C1, allowing the odontoid slide posterioly relative to C1.
This leads to cord compression, particulary in flexion.
This shows the classic “bamboo spine”, due to extensive bridging of syndesmophytes across multiple vertebral bodies.
Ankylosing spondylitis
Without the flexibility of the disc spaces, the rigid AS spine is prone to fracture (arrow) with even mild trauma.
Patients typically have sudden high fevers, followed within 4 weeks by rapind onset of motor, sensory, and usually autonomic dysfunction, sometimes referable to a specific spinal cord level.
Acute viral myelitis
Imaging pattern of acute viral myelitis
The imaging findings typically are a focal area of cord swelling with high signal on T2WI, with variable enhancement.
This is a progressive ascending motor weakness that affects more than one limb, but involves peripheral nerves rather than the spinal cord.
Guillain-Barre syndrome
Another name of Gullain-Barre syndrome
Acute inflammatory polyradiculoneuropathy
This presents as a diffuse leptomeningeal granulomatous nodules, which typically enhance.
Neurosarcoidosis
Appearance is similar to carcinomatous and mycobacterial meningitis, and the distinction must be made on clinical grounds.
What are the common causes of arachnoiditis?
Iatrogenic - including inflammation after spine surgery, spinal anesthesia, or spine “injection” procedures such as epidural nerve blocks.
In arachnoiditis, the normally free-layering lumbar roots become adherent to each other, or to the peripheral wall of the thecal sac, giving the sac what appearance?
Give the sac a “bald” appearance
This occurs roughly 6 to 12 months after initial radiation treatment, with affected areas demonstrating increased signal intensity on T2WI with variable enhancement.
Radiation myelitis
This is the most common causes of spine infection in adults.
Staphylococcus aureus
followed by gram-negative bacteria, particularly Escherichia coli, Pseudomonas, and Klebsiellla.