Having a CT Colonography (CTC) scan

Transcription

1 Having a CT Colonography (CTC) scan Information for Patients In this leaflet: Introduction. 2 What is CT colonography (CTC)? Why do I need a CTC scan?... 2 What do I need to do to before the CTC scan? Where do I go when I arrive at the hospital?.3 Can I bring a relative or friend?...4 What happens during the CTC scan?..4 What happens after the scan?... 4 How do I get my results?....5 Are there any risks or side effects of having a CTC scan?...5 What if I need further investigations or treatment?..6 Any questions? References and more information...6 How do I make a comment about my examination?...7 Page 1 of 7

2 Introduction This leaflet tells you about having a CT colonography (CTC) scan. It explains how the test is done, what to expect, and what the possible risks are. If you have any questions or concerns, please do not hesitate to speak to a doctor or nurse caring for you. What is CT colonography (CTC)? A CT (computed tomography) scanner uses special x-ray equipment and computers to produce images of the part of the body being scanned. These images of the inside of the body can then be examined on a computer monitor. CT colonography (CTC) uses CT scanning to obtain an interior view of the colon (the large bowel) that is otherwise only seen with a more invasive procedure where an endoscope is inserted into the rectum (colonoscopy). Why do I need a CTC scan? CTC is a useful method of assessing the health of the lower bowel: When you have symptoms (such as abdominal pain, constipation, diarrhoea, bleeding from the bowel, anaemia, weight loss), which could be due to bowel disease. As part of bowel cancer screening, to diagnose bowel cancer when it is at an early stage. Your doctor may have advised you to have a CTC scan because: You had a colonoscopy but we couldn t see the whole length of your bowel You have been told that colonoscopy wasn t a suitable investigation for you Alternatively, you may have opted to have a CTC scan rather than a colonoscopy. What do I need to do to before the CTC scan? Bowel preparation It is very important that you have a well-prepared bowel so that we can take good quality images. Before you attend for your scan you will receive a list of dietary restrictions and a bowel preparation medicine. Please follow the instructions you are given very carefully. If you are diabetic, please contact the X-ray department before the date of your scan, as you may need different dietary instructions. Taking tablets and medicines Page 2 of 7

3 Some medications can interfere with this investigation and may need to be temporarily discontinued before your scan. The instructions we send you will give more details and you should discuss this with your doctor before making any changes to your regular medications. If you take Metformin (Glucophage) tablets for diabetes, please let us know on the day of your test as we may ask you to stop taking the tablets for two days after their test. Females Females are asked to contact the Radiology department if you suspect that you may be pregnant OR if the appointment is more than 10 days after the start of your last period. This test uses radiation and there is a risk to the unborn baby if we were to do the X- rays when you are pregnant. When you arrive for your test, you will be asked when your last period started. If it is more than 10 days earlier, your appointment will be postponed. If you are taking the oral contraceptive pill, diarrhoea can make it less effective. Continue taking the pill but use other precautions for the rest of that cycle. Allergy to iodine or intravenous contrast medium You should inform us in advance if you have a known allergy to iodine or intravenous contrast material (dye). Your doctor may prescribe medications prior to the examination to reduce the risk of an allergic reaction. Where do I go when I arrive at the hospital? Please report to the reception desk in the Radiology department (B8) with your appointment letter 10 minutes before your appointment time. Please click on the following link for a site map of the hospital: You will be looked after by a radiographer. He or she will explain the test and answer any questions. Please let them know if you had any problems with your bowel preparation, or if you have any allergies. You will be shown to a private cubicle and asked to change into a clean gown. You will be asked to remove all jewellery and metal from the area to be scanned. Your clothes and valuables will be secured in a locker until after the procedure. You may have a small tube, called a cannula, inserted into one of the veins in your arm. Page 3 of 7

4 Can I bring a relative or friend? You may bring a relative or friend with you to the appointment but, as the examination uses x-rays, for reasons of safety they will not be able to accompany you into the CT scanner room, except in very special circumstances. If you need an interpreter please tell us when you receive your appointment so that we can arrange this. What happens during the CTC scan? You will be taken into the CT Scanning Room and asked to lie on the scanner table on your left side. The radiographer will pass a small flexible tube into your back passage. Some carbon dioxide gas will be passed through the tube to gently inflate your large bowel. Additional gas is then introduced when necessary to keep the bowel inflated. A muscle relaxant may be given through the cannula to reduce any discomfort. The radiographer will then help you into the correct position (this may be onto your front or side) for the first scan. The radiographers will briefly leave the room but they will be observing you closely through the scanner room window. You will be able to talk to them via an intercom system. When the scan starts you will be asked to hold your breath for a few seconds, and you will feel the table moving slowly. The radiographer will then ask you to turn over into the next position (this may be onto your back or side) and they will repeat the scan. They will then check the quality of the images. Occasionally, further scans may be required to look more closely at an area that hasn t shown up clearly. A dye used during x-rays (called a contrast agent) may be given through the cannula to improve scan detail. At the end of the scan, the tube will be gently removed from your bottom and you will be asked to go to the toilet and then get dressed. The whole investigation will take no more than 30 minutes. What happens after the scan? If you have had an injection of contrast into a vein you will need to stay in the department for 20 minutes after your scan. A radiographer or helper will then take the cannula out. Page 4 of 7

5 You may eat and drink as normal as soon as the examination is finished. You may wish to rest at home for the remainder of the day, although most people are able to resume their normal daily activities. How do I get my results? A specialist Radiologist will review the images from your CTC scan and send a report to your doctor. Your GP or hospital Consultant who referred you for the test will see you to discuss the results. Are there any risks or side effects of having a CTC scan? Radiation dose A CTC investigation uses x-rays to produce the images. Medical radiation does carry a very small health risk. The radiation that you receive during a CTC scan is equivalent to approximately 2 years of natural background radiation(from your surroundings).this is considered by the UK Health Protection Agency to carry a very low risk [1]. The CT department monitors radiation doses very carefully and always uses the lowest dose needed to gain good quality images. Expected side effects Minor side effects may include: Dehydration caused by the bowel preparation medicine. You will need to drink plenty of fluids before and after your scan. Dry mouth and blurred vision caused by the muscle relaxant injection (if given). This should wear off within 30 minutes, but please do not drive until your vision is back to normal. Feeling of warmth and occasional strange metallic taste with a feeling as if you have passed urine for a few moments, caused by the contrast agent injection (x-ray dye) if given. Bloating in your tummy during and after the procedure, caused by the gas used to inflate the bowel. This soon wears off once you have been to the toilet and passed wind. Haematoma (bruising) can occur at the injection site. Rare complications More serious complications are very rare, but the radiography staff are well prepared to manage them safely. They will make sure you don t have any of these symptoms before sending you home: Page 5 of 7

6 Feeling faint following injection of the muscle relaxant (if given) Allergic reaction and kidney complications associated with the contrast agent (if given) Abdominal pain Perforation of the bowel (a small hole in the bowel wall). This is very rare, and only happens in about one in every 3,000 cases [2]. Most perforations will heal without treatment, although an overnight hospital stayand antibiotics may be recommended. Painful eye can be caused by the muscle relaxant (if given).this is very rare but if this happens you need to attend a hospital emergency department for an urgent eye assessment Despite these slight risks, your doctor believes it is advisable that you should have this examination, and do bear in mind there are greater risks from missing a serious disorder by not having your scan. What if I need further investigations or treatment? CTC scans are generally accurate at detecting cancer and large polyps. There is however a chance that a small cancer or polyp may not appearon the images. On rare occasions, the radiologist misses a polyp or cancer when it was visible in the images. Following your CTC scan, you may be invited to attend for other investigations. This will be discussed in detail with your GP, Consultant or Specialist Screening Practitioner. If treatment is needed, you will be able to discuss this with a team of specialists. They will offer you the best possible treatment, tailored to your needs. Any questions? We will do our best to make your visit as comfortable and stress free as possible. If you have any questions, or suggestions for us, please contact CT appointments on References and more information [1] Health Protection Agency X-Rays How safe are they? May 2001 [2] Burling D, Halligan S, Slater A, Noakes MJ, Taylor SA. Potentially serious adverse events at CT colonography in symptomatic patients: national survey of the United Kingdom. Radiology 2006, 239(2): For more information about NHS bowel cancer screening, go to: Page 6 of 7

7 How do I make a comment about my examination? If you have any concerns or suggestions following your examination, please contact the Patient Advice and Liaison Service (PALS), Royal United Hospital Bath NHS Trust, Combe Park, Bath BA1 3NG. ruh-tr.patientadviceandliaisonservice@nhs.net Tel: or Page 7 of 7