Head CT

A head CT is a fast exam most often used to look for bleeding, stroke, and head injury. It is frequently the first test in emergency departments.

Uses in emergency settings

A head CT can detect bleeding inside the brain, including epidural, subdural, and subarachnoid hemorrhage. It also helps identify skull fractures and brain swelling after injury.

In stroke, a non-contrast CT is often done first to distinguish hemorrhagic from ischemic stroke. This distinction is critical because treatment differs.

What may not be seen

Early ischemic stroke, especially in the first hours, may not appear clearly on a standard CT. Small abnormalities in the brainstem or cerebellum can also be missed because of bone artifact in these regions.

For this reason, a normal head CT does not always rule out every possibility. Doctors consider symptoms and may order further tests when needed.

Preparation and procedure

Fasting is generally not needed for a non-contrast head CT. The patient lies on a table that moves into a donut-shaped scanner. The exam usually takes only a few minutes.

Patients are asked to stay still and are sometimes given breathing instructions. Tell the staff if you might be pregnant or wear a hearing aid.

Key points

• Often done urgently because it is fast.
• It may not detect small abnormalities in the brainstem.

Educational information, not a substitute for medical advice.