Evaluation of Deep Venous Thrombosis Using Dual-energy CT

Deep vein thrombosis （DVT） was evaluated using virtual monochromatic imaging （VMI） with dual-energy analysis. We used data from 29 patients who were imaged at Showa University Hospital using the pulmonary embolism （PE）/DVT protocol and evaluated based on the diagnostic utility of VMI with dual-energy analysis. By VMI, we compared the computed tomography （CT） values of the femoral veins on both sides and the surrounding muscle tissues at 40keV and conventional imaging; two radiologists performed the visual evaluation in three stages. We also evaluated the CT values of thrombi for cases with DVT. We conducted a retrospective cohort study on 29 patients （18 males and 11 females） with a mean age of 66.8 （range: 31?86） years. DVT was confirmed in four of the subjects （13.7％）. Visual evaluation confirmed a significant difference between the CT values at 40keV and with conventional imaging （2.76 vs. 1.81;?P＜0.05）. CT values in the femoral vein were 274.67 （range: 186.35?63.31） Hounsfield units （HU） at 40keV and 109.46 （range: 74.54?155.66） HU with conventional imaging （P＜0.05）. Contrast-to-noise ratios （CNRs） ［（femoral vein CT value?adductor muscle CT value）/adductor muscle standard deviation （SD）］ were 11.77 （range: 3.93?26.33） HU at 40keV and 9.87 （range: 1.28?27.56） HU with conventional imaging （P＜0.05）. The thrombus/femoral vein ratio （CT value） was 0.34 at 40keV and 0.59 with conventional imaging, while the CNR was 17.52 at 40keV and 4.32 with conventional imaging; both differences were significant. Low-voltage contrast CT is beneficial for enhancing images of veins and it may also be very useful for detecting DVT