RD7.4 | Imaging in Head Injury — Summary & Reflection

KEY TAKEAWAYS

Imaging in Head Injury — Key Points

• Decide who to scan with a validated rule (Canadian CT Head Rule / NICE), not instinct. High-risk features: GCS <15 at 2 h, suspected open/depressed or basal skull fracture, ≥2 vomits, age ≥65, focal deficit, post-traumatic seizure. Any anticoagulated head injury is scanned.
• Non-contrast CT head is the modality of choice for acute trauma — fast, available, no contrast, exquisitely sensitive for blood and fracture. Review brain, bone and subdural windows.
• CT cervical spine when the neck cannot be cleared clinically; MRI for diffuse axonal injury (GCS far worse than CT) and subacute/chronic injury.
• Extradural haematoma: biconvex, does NOT cross sutures, arterial (middle meningeal artery), temporal fracture, lucid interval — time-critical surgical emergency.
• Subdural haematoma: crescentic, crosses sutures but NOT the midline, venous (bridging veins); acute = hyperdense, chronic = hypodense; elderly/anticoagulated.
• Contusion (frontal/temporal poles, may blossom — repeat CT), traumatic SAH (sulcal/cisternal hyperdensity), skull fracture (bone windows; depressed/open need surgery).
• Read mass effect — sulcal/ventricular effacement, midline shift, herniation — these signs often drive surgical urgency.
• Integrate into management: large EDH or deterioration → urgent evacuation; acute SDH >~10 mm or midline shift >~5 mm → evacuation; smaller bleeds/contusions → admit, monitor, control ICP, reverse anticoagulation, repeat CT; normal CT + recovered GCS → conservative with safety-netting. A normal CT does NOT exclude DAI.

REFLECT

On your next surgical or casualty posting, when a head-injury patient arrives, consciously apply the decision rule out loud before the scan is requested: which criteria are present, and is anticoagulation in play? When the CT comes back, name the shape of any collection (biconvex or crescentic?), look deliberately for midline shift and effaced cisterns, and then state the management it implies before the senior does. Watch a 'talk and deteriorate' patient if you ever see one — it teaches, viscerally and permanently, why imaging the well-looking head injury early is the whole point. Linking the rule, the read, and the surgical decision into one continuous chain is what RD7.4 is really asking of you.