Overview of Computed Tomography (CT)

This examination uses a digital imaging system and an x-ray scanner to obtain cross-sectional images of the body. These images will help your doctor in the diagnosis of your condition.

Procedure

You will be required to lie down on the examination table. The table is then moved partially into a tiltable tunnel which contains the X-ray scanner.

Preparation

Please do not take any food or fluid 4 hours before the examination; If you are on a medication called Metformin (Glucophage), do not take it 2 days before, on the day of, and 2 days after, the CT examination;.

For CT Pelvis, do not empty your bladder at least one hour before the scan.

On Arrival

You will be required to change into a hospital gown. A locker will be provided for your belongings but please keep your valuables at home.

The CT Examination

For higher radiation dose CT examinations, e.g. CT of the lumbar spine, you may be asked the first day of your last menstrual period (LMP) if you are a lady of child-bearing age. For lower dose examinations, you may be asked if there is any possibility you may be pregnant.

Depending on the examination, a needle may be introduced into a vein on your hand for injection of a dye to enable clearer diagnosis.

CT of the abdomen and/or pelvis will require drinking of a special fluid to better visualise the bowels.

Please keep still for the entire procedure to help us obtain the clearest images for you. The examination usually takes 10 - 30 minutes, depending on the region being scanned.

Due to the nature of our work, we have to give priority to emergency cases, and may not be able to keep strictly to schedule.

If you have any question about the examination, do not hesitate to ask the radiographer attending to you.

After The Examination

Please do not change out of your hospital gown immediately after the examination. It may be necessary to do some additional views/sequences after the initial images were processed and reviewed.

Results of the examination

The radiologist will review the images and report the findings to your physician, who will then discuss the results with you on your next appointment.

Possible Risks

CT does involve exposure to radiation in the form of x-ray, but the benefit of an accurate diagnosis far outweighs the risk. Nursing mothers should wait for 24 hours after contrast material injection before resuming breast feeding.

The risk of serious allergic reaction to iodine-containing contrast material is rare, and radiology departments are well-equipped to deal with them.

Limitations

X-ray imaging is not usually indicated for pregnant women.