Computed Tomography (CT) Scan (Child)

A Computed Tomography (CT) scan is a specialized imaging test that uses X‑rays together with computer technology to create detailed cross‑sectional pictures of your body. These images help doctors make accurate diagnoses. We hope the following information will help you understand the procedure better and ensure a smooth and comfortable visit to the Department of Diagnostic and Interventional Imaging.

What to expect during the examination?
During your CT scan, you will lie comfortably on a scanning couch. You will not feel any pain; the only sensation you may notice is the gentle movement of the couch as different images are taken. At certain points, the radiographer will ask you to hold your breath for about ten to fifteen seconds to ensure clear images.

In many cases, a contrast medium (also known as X‑ray dye) will be injected into a vein in your arm. This helps highlight your blood vessels and improves the visibility of certain organs and structures. You may feel a brief warmth spreading through your body when the contrast is injected—this is normal. The contrast will naturally pass out of your body through your urine within 15 to 30 minutes.

If you experience any discomfort or pain during the injection, please inform our staff immediately.

How much radiation will I receive?
The amount of radiation used for your scan is kept as low as possible. At these levels, there are no known harmful side effects. If you have any questions or concerns about radiation, please feel free to discuss them with the radiologist.

Will I need to be admitted?
You do not need to be admitted to the hospital for this examination. It is performed on an outpatient basis. However, if you happen to be admitted on the day of your appointment, please inform the ward staff so they can notify the Department of Diagnostic and Interventional Imaging about your scheduled scan.

Medical leave
Please note that no medical leave will be issued on the day of exam except for procedure that is performed under general anaesthesia. An excuse chit can be given upon request.

When to arrive
Please arrive at the Department of Diagnostic and Interventional Imaging at least one hour before the appointment for registration and preparation.

Important Points to Note

1. Examination Duration
   The scan itself usually takes about 15 to 30 minutes. However, for certain scans—such as a pelvic CT—you may need additional preparation time, which can take up to 90 minutes.
2. Medical Conditions to Inform Us About
   When scheduling your CT scan, please let us know if you have any of the following conditions:
   • previous allergy to contrast medium
   • asthma
   • diabetes
   • kidney (renal) disease
   • history of kidney surgery
   • protein in your urine (proteinuria)
     If you have kidney‑related conditions or diabetes, please provide your latest creatinine level (µmol/L) and the date of the test. 
   • If your creatinine level is abnormal, we may repeat a blood test on the day of your appointment.
   • The result takes about one hour.
   • If it remains abnormal, your scan may need to be postponed, cancelled, or an alternative examination may be recommended.
     These steps are taken to protect your kidneys.
3. Pregnancy
   If you are pregnant or think you might be pregnant, please inform the doctor, radiographer, or our reception staff before the scan.
   A urine pregnancy test may be required on the day of the scan if your last menstrual period was more than 28 days ago, to ensure your safety.
4. Personal Belongings
   Please do not bring valuables, jewellery, or large amounts of cash with you for your appointment. 

Preparation for Adult Patients

Preparation requirements vary depending on the type of CT scan and the body area being examined.

1. Food Intake
   Fasting is not required, but please avoid heavy meals. You may have a light meal—such as porridge or a small serving of noodle soup—before your appointment.
2. Hydration
   You are encouraged to drink plenty of water before the scan to stay well‑hydrated.
   For abdominal CT scans, you may be asked to drink additional water just before the procedure.
   You are encouraged to bring your own water bottle; if not, we will provide a foam cup for your use.
3. Pelvic CT Scans
   For pelvic examinations, a small amount of contrast medium may be gently introduced into the rectum to help visualize the large intestine.
4. Bladder Preparation
   Please do not empty your bladder for at least 30 minutes before the scan.
   If you are an inpatient with a urinary catheter, the nurse will be instructed to clamp it before the examination.
5. Contrast Injection
   A small needle may be inserted into your arm if intravenous contrast is needed during the scan.
6. History of Contrast Allergy
   If you have had an allergic reaction to CT contrast in the past, please take the prescribed prednisolone at 12 hours and 2 hours before your appointment, as instructed by your doctor.

Preparation for Children

1. Fasting for CT Angiography
   All CT Angiography examinations require 3 hours of fasting.
2. Fasting for Young Children
   Children aged 6 years and below are required to fast for 3 hours before the scan, as they may need sedation or a contrast study during the procedure.
3. Contrast or Medication
   When needed, a small needle will be inserted to administer contrast medium (X‑ray dye), sedation medication, or drugs used for general anaesthesia.

Fasting & Health Guidelines for Sedation / General Anaesthesia

These instructions help keep your child safe during their scan.
Please read them carefully.

1. Fasting Guidelines
   Fasting is very important before sedation or general anaesthesia.
   If the stomach is not empty, food or liquid may enter the lungs and cause serious complications.
   
   What you need to do
   Please ensure your child stops eating and drinking by the stated time.
   
   Minimum Fasting Times
   Sedation: Fast for at least 3 hours.
   
   General Anaesthesia:
   A nurse will contact you 2–3 days before the scan with detailed fasting instructions.
   
   What your child can have before starting the fast
   A light meal only, such as:
   1 cup of milk or Milo and 1 slice of plain bread, or Milk only
   
   Avoid
   Heavy, oily, or fried foods — these increase the risk of vomiting and other complications.
   
   Important
   If fasting instructions are not followed, the scan may be postponed or cancelled for your child’s safety.
   
   
2. If Your Child Has a Recent Cold (URTI)
   To proceed safely, your child must be well for at least 2 weeks before sedation or anaesthesia.
   This means no fever, cough, or runny nose.
   
   Why this matters
   A recent upper respiratory tract infection can increase the risk of breathing problems during sedation or anaesthesia, including:
   Airway blockage
   Low oxygen levels
   Laryngospasm
   Bronchospasm
   
   If your child becomes unwell
   Please inform us as soon as possible.
   We will assess if it is safe to continue.
   The scan may be postponed or cancelled, depending on your child’s condition.

Consent

Written consent is required for sedation or general anaesthesia.

For patients under 21 years old, a parent or legal guardian must provide consent and accompany the child on the day of the scan.