Objective: To develop dual-energy computed tomography methods for identification of hyperenhancing, hypoenhancing, and nonenhancing small-bowel pathologies.
Methods: Small-bowel phantoms simulating varying patient sizes and polyp types (hyperenhancing, hypoenhancing, and nonenhancing) contained bismuth suspension in the lumen. Dual-energy CT was performed at 80/140 kV and 100/140 kV. Computed tomographic number ratios (CT numbers at low/high kilovoltage) were calculated. Two radiologists evaluated polyp detection and conspicuity using bismuth-only, iodine-only, iodine-overlay, and mixed-kilovoltage displays.
Results: Computed tomographic ratios for bismuth and iodine did not overlap. For hyperenhancing and nonenhancing polyps at 80/140 kV, iodine-overlay display yielded higher detection rate (96%, 94%) and conspicuity score (3.5, 3.1) than mixed-kilovoltage images (88%, 68%; 1.5, 2.7). Mixed-kV images performed slightly better for hypoenhancing polyps (92%, 3.4 vs. <80%, <2.9). Similar results were observed at 100/140kV.
Conclusions: Dual-energy CT and a bismuth-containing enteric contrast permitted simultaneous identification of hyperenhancing, hypoenhancing, and nonenhancing polyps over a range of patient sizes.
From the *Department of Radiology, Mayo Clinic, Rochester, MN; †Department of Radiology, Mayo Clinic, Scottsdale, AZ; and ‡Division of Gastroenterology, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
Received for publication March 21, 2012; accepted May 20, 2012.
Reprints: Joel G. Fletcher, MD, 200 First St SW, Rochester, MN 55905 (e-mail: firstname.lastname@example.org).
The authors report no conflicts of interest.