CT scan of the mastoid bone: what patients should know

It may be used to investigate persistent ear disease, hearing-related concerns, trauma, a suspected complication, or an abnormality affecting the temporal bone. The scan shows anatomy and structural change; your symptoms, ear examination and hearing tests provide additional information.

The mastoid is part of the temporal bone and contains small air-filled spaces connected with the middle ear. A dedicated temporal-bone protocol can display those spaces, the ear canal, middle-ear bones, inner-ear structures and surrounding bone with thin cross-sectional images.

The radiologist looks for patterns such as loss of normal air, fluid or soft tissue where air is expected, bone change, or the effects of previous surgery. Those appearances have several possible explanations and must be matched to the clinical picture. Intravenous contrast is used only when the specific question calls for greater soft-tissue detail.

Tell staff about hearing aids, cochlear implants, ear surgery and other devices or metal near the head. Remove hearing aids, jewellery and removable items when directed. Previous ear images, operation details and hearing-test results may help the care team place the CT findings in context.

Mention pregnancy or possible pregnancy before imaging. If contrast is planned, also report kidney problems, allergies and any earlier contrast reaction, and follow the preparation instructions from the centre. Your head will be positioned carefully; remaining still for image acquisition reduces blur around the tiny ear structures.

Obtain urgent medical assessment for swelling and redness behind the ear with the ear pushed outward, severe headache with neck stiffness, new facial weakness, confusion, fainting, or rapidly worsening illness. Sudden hearing loss also warrants prompt assessment. Urgency comes from these symptoms, not from how frequently a particular diagnosis occurs.

If ear pain, discharge, fever or dizziness is worsening while you await imaging, contact the clinician managing the problem for advice about timing. Following contrast, tell staff immediately about trouble breathing, swelling of the face or throat, widespread hives, or feeling faint.

Ask whether the request is for a dedicated temporal-bone study, which ear or ears will be assessed, and whether contrast is expected. It can also help to confirm how implanted devices affect imaging, whether hearing tests should be reviewed alongside the scan, and who will coordinate any ear, surgical or oncology follow-up.