Xunhui Zhuang, Presenter: Nothing to Disclose

Weihua Feng MD, Abstract Co-Author: Nothing to Disclose

Wenjian Xu PhD, Abstract Co-Author: Nothing to Disclose

Huizhi Cao, Abstract Co-Author: Nothing to Disclose

To investigate the effect of dual energy technique on metal artifact reduction with respiratory motion

A phantom system was used to create one-dimensional motion to simulate respiratory motion .The iodine-containing was configured to 20 mg / cc in 8 plastic tubes, embedded in eight directions of the peripheral phantom, and a metal alloy was embedded in the center of phantom. The motion amplitude in the longitudinal axis of the phantom were2.5, 5.0, 7.5 and 10.0 mm, and the motion frequency of the phantom were 5, 10, 15 and 25 bpm. The phantom was examined using fast kilovoltage switching (80 and 140 kVp). The monochromatic images (40~140keV) were reconstructed and the optimal keV images with lowest metal artifact were selected. The SD values of metal artifacts and background were measured at selected monochromatic imaging and conventional 120 kVp polychromatic imaging under different motion conditions. The results were analyzed by paired-samples T test using the SPSS statistics 17.0, and statistical significance was defined as p<0.05.

The monochromatic imaging at 75 keV could provide the best artifact coefficients. On all corresponding motion conditions, the artifact coefficients of monochromatic imaging were less than that of polychromatic imaging (P<0.05). As the motion frequency and amplitude increased, artifacts coefficient of monochromatic imaging increased, but on frequency motion( 5 bpm ± 2.5mm, 5 bpm ± 5.0mm, 5 bpm ± 7.5mm, 5 bpm ± 10.0mm, 10 bpm ± 2.5mm, 10 bpm ± 5.0mm ), there was no significant difference in artifacts coefficient compared with that of static phantom image(P> 0.05).

This phantom study indicates that respiratory motion can aggravate the metal artifacts, dual-energy technology can reduce the effect in certain low-frequency motion.

kVp switching technique can provide us with high quality keV images and reduce metal artifact even on condition that breathing motion occurs

Zhuang, X, Feng, W, Xu, W, Cao, H, Metal Artifact Reduction with Respiratory Motion Using Dual-Energy Technique: A Phantom Study.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11008601.html