![]() The timing bolus used a 30-mL bolus of iohexol with a 50-mL saline flush.Ī limitation of the rapid-voltage-switching DECT scanner is that it does not provide automated exposure modulation for dual-energy scans. The dual-energy gemstone spectral imaging mode scan was obtained only for the late arterial phase (scan delay of 30–55 seconds after initiation of contrast injection, depending on the results of the timing bolus). For the other 30 patients, a dynamic contrast-enhanced abdominal scan was obtained after injection of 120 mL of iohexol with a 50-mL saline flush delivered at 4–5 mL/s, with scan delays determined on the basis of a timing bolus protocol. For 78 patients, DECT of the abdomen and pelvis was performed in the portal venous phase using the gemstone spectral imaging mode 80 seconds after the initiation of an IV injection of 150 mL of iohexol (Omnipaque 350, GE Healthcare) with a 50-mL saline flush delivered at 3 mL/s. No positive oral contrast agent was given. All patients were instructed to drink 800 mL of tap water within 1 hour before imaging. In addition, we performed a CT phantom experiment to study these artifacts.ĭECT scans were performed on a rapid-voltage-switching DECT scanner (Discovery CT750 HD, GE Healthcare). Therefore, we conducted a study to determine the frequency and appearance of these artifacts in relation to gas interfaces in the bowel on clinical rapid-voltage-switching DECT images. ![]() These artifacts have a striking appearance, but, to our knowledge, have not been previously described. Īt routine abdominal readouts of rapid-voltage-switching DECT scans, we encountered iodine-density image artifacts within the bowel at gas interfaces that resembled disease involving the bowel. Similarly, there is a paucity of published descriptions of artifacts that are specific to DECT. Similarly, iodine-density images generated from DECT scans may be helpful to highlight abnormalities of bowel perfusion, such as to help detect nonenhancement of the bowel wall in bowel ischemia, but few data have been published on the use of DECT for bowel imaging. Iodine-density images highlight differences in contrast material distribution at the time of imaging and are useful in imaging solid organs for the detection of subtle hypervascular or hypovascular liver lesions, enhancing renal tumors, endoleaks from endovascular repairs, pancreatic masses, and gastrointestinal bleeding. Compared with water, soft tissue, and calcium, materials that contain iodine show a high difference in x-ray attenuation when imaged at 80 kVp versus 140 kVp, and this property allows two- or three-material decomposition software to generate iodine-density images from IV contrast-enhanced DECT scans. ![]() One of the transformative benefits of DECT is its ability to distinguish between materials according to their known relative attenuation of two different x-ray spectra. Dual-energy CT (DECT) is an increasingly used technique that provides substantial capabilities compared with conventional CT. ![]()
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