How to read a CT head for bleeding
Other platforms explain it with text and video. In VMS you practice it on the patient.
A non-contrast CT is the fastest way to find bleeding in the head after trauma or a sudden headache or stroke. Recognizing the pattern guides urgent treatment.
Step by step
Check the scan
Confirm the patient and that it is a non-contrast scan. Look at brain, blood and bone windows. [1]
Look for bright areas
Fresh blood looks bright white. Older blood becomes gray and then dark over days to weeks. [2]
Name the bleed by shape
Use the table below. The shape and location tell you which space the blood is in. [2]
Check the spaces around the brain
Look in the grooves, the basal cisterns and the ventricles for blood from subarachnoid or ventricular bleeding. [2]
Look for mass effect
Midline shift, squashed ventricles, missing grooves and blocked cisterns mean rising pressure and need urgent neurosurgery input. [2]
Check the bones
Look for skull fractures, especially over an epidural bleed. [2]
Act on the result
Reverse anticoagulants, control blood pressure per protocol and call neurosurgery. In stroke, the CT must show no bleed before clot-busting drugs are given. [1]
Common errors
- Missing a gray subdural bleed that is a few weeks old.
- Looking only at brain windows and missing thin blood or fractures.
- Not reversing anticoagulation when a bleed is found.
Bleed patterns [2]
| Bleed | Shape on CT | Classic cause |
|---|---|---|
| Epidural | Lens shaped; does not cross skull sutures | Torn artery after skull fracture |
| Subdural | Crescent shaped; crosses sutures | Torn veins; older adults, falls, anticoagulants |
| Subarachnoid | Blood in grooves and cisterns | Ruptured aneurysm or trauma |
| Intraparenchymal | Bright area within the brain | High blood pressure, trauma, amyloid |
Practice it in VMS
In VMS you do this on the patient, not on paper: every step goes on the checklist with a score, and in Teach mode Blocky tells you what comes next.
VMS cases that train this skill
Sources
Facts and steps follow AAMC Core Entrustable Professional Activities (Core EPAs); NCCPA PANCE Content Blueprint. VMS is not affiliated with these organizations. Updated: 2026-10-11.