CT Colonography: Accuracy, Acceptance, and Safety
CT Colonography: Accuracy, Acceptance, and Safety
Recently, the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) published a consensus statement on quality standards for CTC. The American College of Radiology also recently updated its practice guidelines for CTC. Both statements indicate that the patient should be prepared with a low fibre diet and with laxative agents, if possible, prior to the examination. Faecal tagging with iodine or barium is mandatory, as untagged fluid or faecal residue can lead to false-positive or false-negative findings. A thin and flexible rectal tube is recommended for colonic distension. When using a small rectal balloon, this should be deflated in one scan acquisition to prevent masking of a rectal lesion. Automated insufflation of carbon dioxide is the preferred method for colonic distension, as it maximises patient comfort during and after the procedure and improves distension. Prior to colonic distension, some advise the use of 1 mL intravenously administered butylscopolamine as spasmolytic (where available), unless contraindicated. Generally, spasmolytics are not employed for CTC in the USA, while these are widely used in Europe. Image acquisition includes a scan in supine and prone position on a multidetector CT scanner (≥4) using a low radiation dose protocol. Intravenous contrast medium is not required in screening.
Guidelines for CTC Practice
Recently, the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) published a consensus statement on quality standards for CTC. The American College of Radiology also recently updated its practice guidelines for CTC. Both statements indicate that the patient should be prepared with a low fibre diet and with laxative agents, if possible, prior to the examination. Faecal tagging with iodine or barium is mandatory, as untagged fluid or faecal residue can lead to false-positive or false-negative findings. A thin and flexible rectal tube is recommended for colonic distension. When using a small rectal balloon, this should be deflated in one scan acquisition to prevent masking of a rectal lesion. Automated insufflation of carbon dioxide is the preferred method for colonic distension, as it maximises patient comfort during and after the procedure and improves distension. Prior to colonic distension, some advise the use of 1 mL intravenously administered butylscopolamine as spasmolytic (where available), unless contraindicated. Generally, spasmolytics are not employed for CTC in the USA, while these are widely used in Europe. Image acquisition includes a scan in supine and prone position on a multidetector CT scanner (≥4) using a low radiation dose protocol. Intravenous contrast medium is not required in screening.