CHICAGO--Dual-energy CT (DECT) offers enhanced disease characterization, high diagnostic yield and powerful clinical applications, often with lower radiation doses, according to a presentation given Nov. 30 at the 96th annual scientific meeting of the Radiological Society of North America (RSNA).
DECT acquires images using two x-ray sources and two x-ray detectors mounted on a single CT gantry, essentially embodying two CT scanners in one (dual-source CT). The detectors scan the patient at independent energy levels (such as 80 and 140 kV) to create an average image upon completion, while administering as little as half the radiation dose of single-source CT.
Using DECT with iodine contrast enables radiologists to map different anatomical structures' dissimilar absorptions of iodine. These varying chemical absorptions indicate distinct structures and characteristics of organs and bones, offering greater precision for differentiating the existence and progression of disease in patients, according to Thorsten R. Johnson, MD, associate professor of radiology at the University Hospital of Munich-Grosshadern in Germany.
"Specificity and sensitivity are quite good," explained Johsnon, with overall diagnostic yield of approximately 88 percent in the studies he reviewed.
Johnson highlighted a number of successful applications of DECT:
• Bone angiography: differing anatomical absorptions of contrast enable physicians to identify and remove bones from the image, which is useful for imaging carotid stenosis.
• Kidney imaging: physicians can use DECT to differentiate uric acid in the kidneys and visualize renal stones.
• Lung perfusion: useful for interpreting the significance of pulmonary emboli.
According to Johnson, sufficient evidence from trials demonstrates that DECT is prepared for clinical use in these indications, as well as for providing enhanced visualization and treatment of cancers, cysts and lymphoma.