Without contrast: possibilities and limitations
Native CT perfectly shows stones of any composition (including X-ray negative for a regular image), calcifications, blood, air, large tumors and cysts, and organ sizes. To assess the structure of the liver, pancreas, the nature of formations and blood vessels, intravenous contrast is needed - if the radiologist sees a suspicious formation, he may recommend an additional examination with contrast (three-phase study) or oral contrast to evaluate the intestines. Preparation: do not eat for 4 hours, eliminate gas-forming foods the day before.
Indications
- abdominal pain of unknown cause, acute conditions (appendicitis, pancreatitis, intestinal obstruction, perforation);
- tumors of the liver, pancreas, kidneys, adrenal glands, intestines, uterus, prostate - detection and staging;
- abdominal trauma, organ damage, internal bleeding;
- kidney and ureteral stones (non-contrast CT is the most accurate method);
- cysts, abscesses, enlarged lymph nodes, ascites;
- control after operations and tumor treatment.
What is MSCT
Multislice computed tomography is a layer-by-layer X-ray study in which detectors receive dozens of sections up to 0.5–1 mm thick in one revolution of the tube, and a computer builds a three-dimensional image of the organ. MSCT is performed in 5-15 minutes, accurately shows bones, lungs, stones, hemorrhages, tumors and vessels (with contrast), and is often the method of choice for trauma and acute conditions when MRI is too long or contraindicated.
Preparation and contrast
Non-contrast MSCT does not require preparation. Before a study with intravenous contrast, a test for creatinine (kidney function) and the absence of an allergy to iodine are required; 4–6 hours without eating; When taking metformin, agree on a break with your doctor. Contrast (Unigexol) is administered using an automatic injector; a feeling of warmth for 1–2 minutes is normal. To examine the abdominal and pelvic organs, oral contrast is used, which is drunk 30–60 minutes before the scan. Remove metal objects from the examination area. The radiologist’s conclusion is completed within 1–2 hours, the images are issued on film and disk.
Radiation exposure and safety
Modern devices use low-dose protocols; the dose for one study is comparable to several months of natural background and does not accumulate dangerously when prescribed appropriately. MSCT is not performed on pregnant women (except for vital indications); for children - according to strict indications with a minimum dose. Iodine contrast is contraindicated in severe renal failure, iodine allergy and uncontrolled hyperthyroidism. Pacemaker and metal implants are not a contraindication, unlike MRI.
