Dual Energy Fusion Technology Using Dual Source CT In The Diagnose And Clinical Application Of Pulmonary Embolism

Objective: To compare the clinical diagnostic value of pulmonary embolism with dual source CT non-linear image blending technique as compared with the linear image blending technique and standard single-energy CT(SECT; 120 kv SECT).Methods: 34 patients suspected pulmonary embolism underwent dual-source, dual-energy CTPA(80 /140 kv mode) scan and 28 patients used the conventional 120 kv SECT image sets in the arterial phase.Then,we obtained non-linear blending images(NLB1(λ=150HU,ω=200HU),NLB2(λ=80HU,ω=200HU),NLB3(λ=80HU,ω=400HU)),0.6 linear blending images and 120 kv SECT images. CT values, image noise of pulmonary arteries included main pulmonary artery, left pulmonary artery and left lower pulmonary artery of the 5 sets images were measured, and then the SNR were calculated. The differences of the 5 sets images in CT values, noise and SNR were compared using repeated-measures analysis of variance(ANOVA) and LSD-t test(p<0.05).The minimum CT value and SNR were eliminate. Then, the image quality scores of the pulmonary arteries in the image sets from MIP,MPR and VR by two radiologists with 5 years, 7 years working experience,respectively, using a double blind method. The patient’s name, age, and sex, as well as the CT parameters and all hospital record numbers, were removed from the images. The images of each set were presented in a random order to each of the readers at the same workstation. Readers were allowed to modify window width and level at their own discretion. The image quality score differences of the 4 sets were compared using Friedman test for multiple paired samples. The independent t-test was used to compare age, sex, BMI, and effective dose were compared between DECT and SECT protocols.Results:1.The CT value, SD and corresponding SNR of pulmonary in Dual energy set are superior to those in conventionalscan(120 kv). NLB2, NLB3 sets are superior to the LB set; In the NLB3(λ=80, ω=400),the CT value, SD and SNR of all pulmonary artery are all best among 5 sets. There were statistically differences in the image quality scores among 4 sets(p <0.05). 2.The scores of the mixed energy images with NLB3(λ=80,ω=400)set. 3.The effective radiation dose for the DECT protocol(2.9±1.1m Sv) was much lower than the SECT protocol(3.8±0.8m Sv)(p <0.05).Conclusion: 1.The non-linear image blending technique of DECT can improved vascular visualization, pulmonary emboli detection rate and image quality of MSCTPA, thus, significantly improve the diagnostic accuracy of pulmonary embolism.2.In NLB algorithms, smaller λ and larger ω combination can significantly improve SNR of the image, recommended for clinical reference.3.The effective radiation dose of the second generation DECT protocol was much lower than the SECT protocol(p <0.05),which is beneficial to the patient’s health and is recommended for clinical reference.