Understanding your imaging
Plain-language guidance on how CT, ultrasound, MRI and X-ray help your doctor — and how to prepare for your visit.
Educational information, not a diagnosis; local protocols and clinician assessment determine imaging.
Neither test is “better” in every situation. Your doctor chooses based on your symptoms, age, pregnancy status and what they need to see.
Uses ionizing radiation; contrast may need kidney/allergy checks. Usually avoided in pregnancy unless essential.
Views can be limited by bowel gas or body habitus; results depend on the area examined and operator.
Available at Centre — contact reception
Tap a scenario to see how imaging is often chosen. These are general patterns, not rules.
Adults (not pregnant)
Low-dose non-contrast CT is commonly preferred to detect stones and their size and position. Ultrasound may also be used, depending on the clinical question.
Pregnancy & children
Ultrasound first in pregnancy, and often first in children, to avoid radiation.
Safety note
Fever with flank pain, a single kidney, or inability to pass urine needs urgent assessment.
CT uses ionizing radiation. If you are or may be pregnant, always tell your doctor and our staff before any CT or X-ray.
Search your test to see how to get ready.
Clinical exceptions
Tell staff if you are or may be pregnant.
Follow your appointment-specific instructions.
Clinical exceptions
Diabetes medicines (e.g. metformin), prior contrast reaction, kidney disease, thyroid disease or pregnancy — inform staff in advance.
Follow your appointment-specific instructions.
Clinical exceptions
Pacemakers, cochlear implants, metal fragments, aneurysm clips, claustrophobia or pregnancy must be discussed before the scan.
Follow your appointment-specific instructions.
Clinical exceptions
People with diabetes, children and frail patients may need adjusted fasting.
Follow your appointment-specific instructions.
Clinical exceptions
A transvaginal scan, if needed, is done with an empty bladder and your consent.
Follow your appointment-specific instructions.
Clinical exceptions
Bleeding, severe pain or reduced baby movements — seek urgent care, do not wait.
Follow your appointment-specific instructions.
Clinical exceptions
If you have fluid restriction (e.g. heart or kidney failure), ask before drinking extra water.
Follow your appointment-specific instructions.
Clinical exceptions
Sudden leg swelling with chest pain or breathlessness is an emergency.
Follow your appointment-specific instructions.
Clinical exceptions
Tell staff if you are or may be pregnant.
Follow your appointment-specific instructions.
Clinical exceptions
Breast implants, pregnancy, breastfeeding or a new lump — inform staff.
Follow your appointment-specific instructions.
Clinical exceptions
If you take insulin or diabetes tablets, ask your doctor how to adjust doses — watch for low sugar.
Follow your appointment-specific instructions.
Clinical exceptions
Menstruation or recent antibiotics can affect results — tell staff.
Follow your appointment-specific instructions.
Supporting appropriate, radiation-conscious imaging decisions.
Include the clinical question, relevant history, pregnancy status and prior imaging on the request.
Consider ultrasound or MRI first where diagnostic yield is comparable, especially in children, pregnancy and young adults. Use low-dose CT protocols where appropriate.
Share renal function, prior contrast reactions and relevant medications to support safe contrast use.
Pathways on this page reflect common practice patterns (e.g. ACR Appropriateness Criteria); final protocol is decided with the reporting radiologist.
No. Each answers different questions. Ultrasound is often first for the gallbladder, pelvis, pregnancy and children; CT is often preferred for stones and many causes of acute pain in adults.
CT uses more radiation than an X-ray. We use the lowest dose that answers the clinical question. The benefit should outweigh the small risk.
Tell your doctor and our staff before any CT or X-ray. Ultrasound and MRI are usually preferred in pregnancy.
Ultrasound is available at the centre — please contact reception to schedule. CT, MRI, X-ray and mammography can be booked online.
Do not stop any medicine unless your doctor tells you to. Ask about diabetes medicines before fasting or contrast scans.
Do not wait for a scheduled scan. Go to the nearest emergency department or call 108 / 112 if you have:
Our reception team can help with appointments, ultrasound scheduling and preparation.
Call reception
Available at Centre — contact reception