Abdominal Radiology Quiz

◎ Stomach: usually contains air, normal diameter is 3cm in a horizontal X-ray ◎ Small bowel: contains a small amount of air in 2 or 3 loops, normal diameter is 3cm in a horizontal X-ray ◎ Large bowel: contains air in the rectum and sigmoid, with varying amount of gas in the rest of the large bowel, normal diameter is 6cm in a horizontal X-ray for the caecum and 6cm and 9cm for the large bowel in the supine and standing position, respectively ◎ X-ray and fluoroscopy: same but fluoroscopy provides real-time moving video of internal tissues ◎ Fluoroscopy: advantage is excellent in evaluating the bowel lumen and mucosa, disadvantage is radiation and poor in evaluating extra-luminal pathologies ◎ Indications for fluoroscopy: assessing the mucosal outline, abdominal pain, gastroesophageal reflux, pregnancy, bowel obstruction, bowel perforation with barium type of contrast ◎ Barium swallow, meal, follow through, and enema: different types of studies used to assess the esophagus, stomach, small bowel, large bowel, and rectum ◎ Barium enema: indicates colon mass/malignancy with an apple core appearance, CT scan, multiple X-rays, and oral contrast are used for diagnosis ◎ CT scan: indicates soft tissue details, excellent in diagnosing extra-luminal lesions, and diagnosing the cause of bowel obstruction, but it uses radiation and is relatively expensive ◎ MRI: safe in pregnancy, gives much more soft tissue details, and is excellent in diagnosing abdominal solid organ lesions, but it is expensive and requires a long scanning time ◎ Indications for MRI: diagnosing abdominal solid organ masses, sensitive to motion, and inflammatory bowel disease, but it is a relative contraindication in early pregnancy and renal failure without IV contrast. ◎ X-ray, fluoroscopy, CT scan, and MRI: have different indications and contraindications for abdominal imaging. ◎ Gravity affects the distribution of air in the stomach and the large bowel. ◎ The oral contrast reveals the specific characteristics of the small bowel and the liver in X-ray imaging. ◎ Air fluid levels in the large bowel suggest the presence of intestinal obstruction. ◎ Free air under the diaphragm indicates perforation of the gastrointestinal tract. ◎ Barium is not recommended for use in suspected leaks or bowel preparations due to its strong effect on the protein cavity.