CT Thoracic Spine — Unenhanced, Thin Section
C7-T1 through L1-L2, with the vertebral level unambiguously countable from a fixed landmark.
Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.
When to use it
- Suspected thoracic spine fracture after trauma, including in the ankylosed spine.
- Characterisation of a lesion identified on radiographs or on a staging study.
- Assessment of bony detail or instrumentation where MRI is contraindicated or already done and insufficient.
Technique
- Where a contrast-enhanced chest or trauma CT has already been acquired, dedicated thin reformats from that dataset usually answer the question without a second exposure — check for existing data before scanning.
- Count levels from a consistent landmark and state the convention used, particularly with transitional anatomy.
Where it goes wrong
- Rescanning a region already covered by a trauma or staging acquisition is avoidable dose; the reformats are the study.
- Poor sagittal reformat quality from a thick primary acquisition hides subtle endplate and posterior element fractures.
- Level miscounting in the presence of transitional vertebrae has surgical consequences.
Clinical questions that reach this study
Contrast
Acquisition
- Breathing
- Suspended respiration where the patient can comply.
- Reconstruction
- Thin-section bone and soft-tissue reconstructions with sagittal and coronal reformats.
- Preparation
- No preparation. Arms above the head where the patient can tolerate it.
Phases
Each phase is authored once and shared across every protocol that uses it, so the physiology below is the same wherever you meet it.
- Non-contrast (unenhanced)No injection. Acquired before any contrast is given.
Shows intrinsic tissue attenuation, and nothing else. The transferable principle is that contrast is anti-signal for anything that is already dense: calcification, acute haemorrhage, urinary and biliary calculi, iodine-containing or haemorrhagic fluid, and intrinsic fat all lose conspicuity, or become uninterpretable, once surrounding tissue enhances. It is also the only baseline against which enhancement can be measured, so any protocol that quantifies enhancement or washout (a lesion "enhances by X HU", adrenal absolute washout, renal mass characterisation) is arithmetically impossible without it. Conversely, an unenhanced series adds dose and no information whenever the question is purely about vascularity or perfusion.
Safety checks this protocol carries
Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.
- Child-sized technique and contrast dose· radiographer at scan
- Pregnancy status before an ionising exposure· radiographer at scan