CT Scan – Pelvis

About a CT scan of the pelvis

The pelvis is the lowest part of the trunk, between the tummy and the legs. It is formed by a ring of bones (the hip bones, sacrum and coccyx) that protects the bladder, the lower bowel and rectum, and the reproductive organs: the womb and ovaries, or the prostate. It also contains major blood vessels and lymph nodes. A CT (computed tomography) scan uses X-rays and a computer to make detailed cross-section pictures of the area.

A pelvis CT may be used to look at:

• fractures of the pelvic ring and hip socket, and planning surgery for them
• the pelvic bones, including bone lumps, and the joints such as the sacroiliac joints
• lumps and enlarged lymph nodes in the pelvis
• collections of fluid or pus (abscesses), and problems after surgery
• the bladder and lower bowel

Because many problems in the lower tummy can also affect the upper tummy, doctors often request a CT of the abdomen and pelvis together. For the womb, ovaries and prostate, ultrasound or pelvic MRI usually shows more detail without radiation. For the hip joint, see hip CT. Your referrer will say which scan is best.

What happens during the scan

You may be asked to drink water or a contrast drink in the hour before your scan, and to have a comfortably full bladder. You lie on your back on the scanner bed with your arms raised or resting on your chest. The bed moves through a short, open ring while your pelvis is scanned. The radiographer controls the scanner from the next room, but can see, hear and talk to you throughout. The scan itself takes only a few minutes.

For some CT scans, an injection of contrast dye is given through a small cannula in a vein, usually in your arm or hand, to make blood vessels and organs show up more clearly. CT contrast contains iodine. As it goes in you may feel warm and flushed, notice a metallic taste, or feel as if you are passing urine; these feelings pass within a minute or two. Allergic reactions are uncommon, and you may be asked to wait for up to 30 minutes afterwards. Where contrast is needed, it is charged separately.

Is CT safe?

CT uses X-rays, which are a type of ionising radiation. A CT of the pelvis covers part of the area included in a CT of the abdomen and pelvis (about 10 mSv), so the dose is usually lower. Because the reproductive organs are in the scan area, the scan is only done when it is likely to help. The risk from a single scan is very small, and every CT scan is checked by a radiologist or radiographer to make sure the benefit of the scan outweighs the risk, as required by the Ionising Radiation (Medical Exposure) Regulations. If you have had other CT scans recently, tell us when you book.