CT Scan of the Brain: Procedure, Uses & What to Expect

A computed tomography (CT) scan of the head uses a rotating X-ray beam and computer reconstruction to create detailed cross-sectional images of the brain, skull, and sinuses.

Procedure

1. Preparation: Remove metal (jewelry, hairpins, dentures). Contrast (IV iodine) may be used for vascular/tumor evaluation—requires renal function check (eGFR) and allergy history.
2. Positioning: Supine on motorized table; head immobilized in holder.
3. Scan: Table moves through gantry; X-ray tube rotates. Duration: 10–30 seconds (non-contrast); longer with contrast phases.
4. Post-Scan: Resume normal activities; hydrate if contrast given.

Common Indications

• Trauma: skull fracture, intracranial hemorrhage (epidural, subdural, subarachnoid, intraparenchymal).
• Stroke: rule out hemorrhage before tPA; detect early ischemic changes.
• Headache: thunderclap, new/worsening pattern, focal neuro signs.
• Hydrocephalus, mass effect, shift.
• Sinusitis, orbital pathology.
• Pre-surgical planning.

Limitations

Less sensitive than MRI for posterior fossa, demyelination, small metastases, early ischemia (<6 hrs). Involves ionizing radiation (~2 mSv).