ABSTRACT
Objective To investigate the optimal monochromatic parameters of CT angiography (CTA) on small feeding arteries of abdominal tumors using single source dual-energy CT with gemstone spectral imaging (GSI) technique.Methods The clinical and medical imaging data of 32 patients with abdominal malignant tumor were analyzed retrospectively during January to April 2012.Three phase-enhanced CT scans (Discovery CT750 HD,GE Heahhcare,Milwaukee,USA) of the abdomen were recorded using the GSI technique on 32 patients.The minor feeding arteries of tumor with diameter between 1.5 mm to 3.0 mm were reconstructed by 140 kVp mixed energy,66 keV,and optimal monochromatic mode respectively.After CT scanning,the original data were processed with layer and interval of 0.625 mm,the 140 kVp mixed energy images and 70 keV monochromatic images were obtained with standard algorithm.The original images were conveyed to AW4.5 work-station to process furthermore,then the data of the optimal monochromatic group and 66 keV group were reconstructed.Comparative parameters include contrast-to-noise ratio (CNR),signal-to-noise ratio (SNR) and subjective scores of the small feeding arteries CTA quality.Subjective scores were evaluated by two radiologists according to the sharpness and resolution of the small feeding arteries.One-way ANOVA was used to for statistical analysis.Results CNR of the optimal monochromatic group,the 66 keY group,and the 140 kVp mixed energy group were 21.70 ±9.74,16.63 ±7.60,and 9.85± 6.76,respectively.SNR were 35.05 ± 17.75,26.77 ± 11.51,and 16.32 ± 9.5,respectively.Subjective scores were 4.58 ± 0.40,3.55 ± 0.57,and 2.75 ± 0.46,respectively.CNR,SNR and subjective scores had significant difference among groups (F =17.11,15.73 and 116.01,P ＜ 0.01).The optimal monochromatic group was superior to the 66 keV group and the 140 kVp mixed energy group.Conclusion The optimal monochromatic mode can improve CTA quality of small feeding arteries of abdomen malignant tumors with GSI technique using single source dual-energy CT.