The CT cervical spine or C-spine protocol serves as an examination for the assessment of the cervical spine. It is usually performed as a non-contrast study. In certain situations, it might be combined or simultaneously acquired with a CT angiography of the cerebral arteries or a CT of the neck. It also forms a part of a polytrauma CT or might rarely be done as a CT myelogram in situations where MRI is contraindicated.
Note: This article aims to frame a general concept of a CT protocol for the assessment of the cervical spine. Protocol specifics will vary depending on CT scanner type, specific hardware and software, radiologist and perhaps referrer preference, patient factors e.g. implants, specific indications.
A typical CT of the cervical spine might look like as follows:
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Images:
Indications
Typical indications include the following 1-4:
congenital anomalies
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if MRI is contraindicated
image guidance (e.g. cervical spinal epidural injections)
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CT myelography
if MRI is contraindicated or metallic implants prevent sufficient image quality
Purpose
The most common purpose of a CT of the cervical spine is the timely diagnosis and classification or exclusion of cervical spine injuries and the evaluation of the osseous spinal canal including 1-3:
In the setting of vertebral metastasis or spinal tumors this also includes the assessment of the following:
fracture risk: spinal instability neoplastic score (SINS)
cord compression risk: epidural spinal cord compression (ESCC) scale
Technique
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patient position
supine position
both arms next to the body, shoulders pulled down
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tube voltage
≤120 kVp
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tube current
as suggested by the automated current adjustment mode
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scout
from above the temporal bone to the manubrium sterni
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scan extent
should include the base of the skull and the first thoracic vertebra
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scan direction
craniocaudal
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scan geometry
field of view (FOV): 120-200 mm (should be adjusted to increase in-plane resolution)
slice thickness: ≤1 mm, interval: ≤0.75 mm
reconstruction algorithm: bone, soft tissue
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multiplanar reconstructions/reformats
sagittal images: sagittal aligned through the center of the dens and the vertebral bodies
coronal images: coronal aligned to the transverse processes
axial images: perpendicular to the cervical spine and the neck
slice thickness: ≤1.5 mm, overlap 50%
Practical points
patient positioning prior to scanning might reduce and facilitate multiplanar reconstructions
shoulder pull-down might allow for safe dose reduction
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dose optimization 5-8
use iterative reconstruction algorithms if available
tube current might be lowered to as low as 105-150 mAs 6-8
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imaging of implants 5
use monochromatic reconstructions in dual-energy CT scans
use additional wide window setting
might require a higher tube potential
the threshold for a CT instead of radiographic cervical spine series should be low in the setting of an adequate cervical spine trauma (as determined by clinical criteria e.g. NEXUS criteria or Canadian C-spine rule) 1-3