MRI of the cervical spine and brain

Topographical diagnosis of Horner syndrome

When examining patients with Horner syndrome (oculosympathetic paresis), the primary task of the radiologist is to locate the level of the lesion along the three-neuron sympathetic pathway.

First-order neurons descend from the hypothalamus to the spinal cord at the cervicothoracic junction (cervicothoracic junction). If the clinical picture points to pathology in this specific segment, MRI of the brain and cervical spine is the method of choice.

During the examination, the physician purposefully rules out:

• Mass lesions of the pituitary gland and brainstem.
• Acute cerebrovascular events (infarctions).
• Demyelinating diseases.
• Chiari malformation.
• Syringomyelia, neck trauma, and marked cervical spondylosis.

Note: when pathology of the 2nd and 3rd neurons (from the cervicothoracic junction to the orbit) is suspected, CT angiography from the aortic arch to the vertex is more appropriate.

Evaluation of the orbits and cranial nerves

MRI is the first-line method when optic nerve pathology (neuritis or neuropathy) is suspected, as well as in ophthalmoplegia. In the latter case, imaging allows tracing the entire complex transit of cranial nerves: through the brainstem nuclei and brainstem, cisternal segment, skull base foramina, and cavernous sinus all the way to the superior orbital fissure.

Orbit MR scanning technique:

• Data acquisition requires separate scans in the axial and coronal planes. Slice thickness must not exceed 3 mm.
• The baseline protocol includes T1-weighted images (before and after contrast enhancement) and T2-weighted scans with fat saturation (fat-suppressed).
• Strict rule: orbital imaging must always be accompanied by T2-weighted scanning of the entire brain to reliably rule out concomitant intracranial pathology.

Visualization of the craniocervical junction in Chiari II malformation

The craniocervical junction is a critical area in congenital hindbrain malformations, which include Chiari II anomaly (Arnold-Chiari). This malformation is almost always associated with lumbosacral myelomeningocele.

Tomograms of the cervical spine and head reveal a classic pattern of changes:

1. Small posterior cranial fossa with low tentorium attachment.
2. Downward displacement of the cerebellum, pons, medulla oblongata, and cervical spinal cord through the enlarged foramen magnum (foramen magnum).
3. Kinking of the medulla oblongata (medullary kinking), flattening of the pons, and beaking (beaking) of the midbrain tectum.
4. The fourth ventricle is displaced downward, elongated, and slit-like (if enlarged, it indicates the development of hydrocephalus).

MRI is the unsurpassed method for detecting such formidable complications of Chiari II as craniocervical junction compression and the formation of an intramedullary cyst — syringomyelia (syrinx).

Diagnosis of spinal cord tumors

For the evaluation of neoplastic lesions of the spine and spinal cord (according to the WHO histological classification), MRI is the unalternative method of choice. It directly visualizes not only the spinal cord, but also the contents of the dural sac, ligamentous apparatus, and nerve roots.

• STIR: The scanning protocol must include the STIR sequence (short tau inversion recovery).
• Invasion assessment: MRI accurately determines bone marrow infiltration, compression of neural structures, epidural extension, and paraspinal lesions.
• Tractography: Diffusion tensor imaging (DTI) makes it possible to trace the relationship between the tumor and white matter tracts. Thus, in ependymoma, fibers are usually displaced to the periphery, whereas in spinal cord astrocytoma, the tumor displaces them anteriorly.

Class and exam questions

What else to study on this topic

• Radiography, ultrasound, and CT of the orbits: capabilities, indications, and limitations of each method.
• Imaging features of congenital eye pathologies (Coats disease, persistent hyperplastic primary vitreous).
• Holoprosencephaly and other disorders of ventral induction of the brain.
• Fluorodeoxyglucose PET (FDG-PET) in evaluating malignancy and progression of CNS tumors.
• X-ray myelography: strict indications in modern practice and technique.
• Spinal angiography: transition from CT/MR screening to digital subtraction angiography (DSA).

Other topics in the "Spine" section

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