Alvin C. Silva MD, Presenter: Research agreement, General Electric Company

Srigayatri D Bollepalli MBBS, Abstract Co-Author: Nothing to Disclose

Amy Kiyo Hara MD, Abstract Co-Author: License agreement, General Electric Company Researcher, General Electric Company

Alison M. Robinette MD, Abstract Co-Author: Nothing to Disclose

Robert Gene Paden, Abstract Co-Author: Nothing to Disclose

Rishi K. Gosalia MD, Abstract Co-Author: Nothing to Disclose

Jessica Marie Ruhland MD, Abstract Co-Author: Nothing to Disclose

William Pavlicek PhD, Abstract Co-Author: Nothing to Disclose

To compare image quality of conventional 140kVp and monochromatic 70keV images and determine if single source dual energy CT (ssDECT) can detect enhancement of small hepatic and renal lesions better than single energy 140kVp images.  

46 patients with 28 liver lesions (13 cysts, 15 metastases; average size = 12 mm) and 36 renal lesions (21 nonenhancing, 15 enhancing, average size =18 mm) underwent contrast-enhanced ssDECT at 80/140 kVp. The following datasets were evaluated:1)140kVp, 2) 70keV monochromatic, 3) material density (MD) water/iodine images, 4) MD iodine with color, and 5) spectral attenuation curves from 40-140 keV. Each dataset was graded independently by two radiologists blinded to pathology for lesion enhancement and diagnostic confidence (1 least, 5 most). The conventional 140kVp and DECT 70keV monochromatic images were compared for individual lesion conspicuity and sharpness, as well as overall image quality (IQ) using the following scale: 1 = 140kVp significantly better; 2 = 140kVp mildly better; 3 = Both equivalent; 4 = 70 keV mildly better; 5 = 70 keV significantly better.  

For both readers, the sensitivity, specificity and confidence was lowest using 140kVp or 70keV images alone (40-67% sensitivity, 33-48% specificity, 1.8-2.6 confidence). Both readers had improved performance when adding MD images with color and attenuation curves (80-87% sensitivity, 71-95% specificity, 3.6-4.5 confidence). The sensitivity/specificity/confidence for MD images without color was 93%/76%/2.8 for reader 1 and 60%/48%/2.9 for reader 2. There were no differences in overall IQ, artifacts, lesion conspicuity or sharpness when comparing 140kVp and 70keV images.  

DECT MD images can help improve diagnostic accuracy and confidence for lesion enhancement compared to conventional CT. It may be possible to use monochromatic 70 keV images in place of 140kVp images when evaluating DECT exams as both had similar overall image quality and performance.   

CT indeterminate liver and renal lesions are common and the frequency and associated costs for clinical work-up could be decreased with the use of ssDECT.

Silva, A, Bollepalli, S, Hara, A, Robinette, A, Paden, R, Gosalia, R, Ruhland, J, Pavlicek, W, Differentiating Enhancing vs Nonenhancing Lesions in the Liver and Kidney: Comparison of Single- and Dual-Energy CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034557.html