In vivo differentiation of complementary contrast media at dual-energy CT.
OBJECTIVE
To evaluate the feasibility of using a commercially available clinical dual-energy computed tomographic (CT) scanner to differentiate the in vivo enhancement due to two simultaneously administered contrast media with complementary x-ray attenuation ratios.


METHODS
Approval from the institutional animal care and use committee was obtained, and National Institutes of Health guidelines for the care and use of laboratory animals were observed. Dual-energy CT was performed in a set of iodine and tungsten solution phantoms and in a rabbit in which iodinated intravenous and bismuth subsalicylate oral contrast media were administered. In addition, a second rabbit was studied after intravenous administration of iodinated and tungsten cluster contrast media. Images were processed to produce virtual monochromatic images that simulated the appearance of conventional single-energy scans, as well as material decomposition images that separate the attenuation due to each contrast medium.


RESULTS
Clear separation of each of the contrast media pairs was seen in the phantom and in both in vivo animal models. Separation of bowel lumen from vascular contrast medium allowed visualization of bowel wall enhancement that was obscured by intraluminal bowel contrast medium on conventional CT scans. Separation of two vascular contrast media in different vascular phases enabled acquisition of a perfectly coregistered CT angiogram and venous phase-enhanced CT scan simultaneously in a single examination.


CONCLUSIONS
Commercially available clinical dual-energy CT scanners can help differentiate the enhancement of selected pairs of complementary contrast media in vivo.
Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, Box 0628, M-372, San Francisco, CA 94143-0628, USA.
John
J
Mongan
Samira
S
Rathnayake
Yanjun
Y
Fu
Runtang
R
Wang
Ella F
EF
Jones
Dong-Wei
DW
Gao
Benjamin M
BM
Yeh
D000284:Administration, Oral; D000818:Animals; D001729:Bismuth / Q000008:administration & dosage*; D003287:Contrast Media / Q000008:administration & dosage*; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage*; D009942:Organometallic Compounds / Q000008:administration & dosage*; D019047:Phantoms, Imaging; D011817:Rabbits; D012459:Salicylates / Q000008:administration & dosage*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D017973:Tungsten Compounds / Q000008:administration & dosage*
D003287:Contrast Media; D009942:Organometallic Compounds; D012459:Salicylates; D017973:Tungsten Compounds; D007472:Iohexol; C015715:bismuth subsalicylate; C025399:sodium tungstate(VI); D001729:Bismuth