A Preliminary Study Of CT Angiography On Small Tumor Blood Supply Arteries Of Gastrointestinal Tract Malignant Tumors With Low Concentration Contrast Medium Optimizing Gemstone Spectral Imaging Technique Using Single Source Dual-energy CT

Objective: To investigate the low concentration contrast medium combined withoptimal monochromatic parameters of CT angiography (CTA)on small tumor bloodsupply arteries of gastrointestinal tract malignant tumors using single sourcedual-energy CT spectral imaging(GSI)technique.Meterials and Methods: This study was approved by the ethics committee of ourhospital. The clinical and medical imaging data of71patients (BMI＞25kg/m2) withgastrointestinal tract malignant tumors were analyzed prospectively during March toDecember2013. All the cases were randomly divided into two groups termed A and B.Group A contained33cases using high concentration of contrast medium in ro utinescan, lines of conventional120kVp polychromatic energy full abdominal scan andtri-phase dynamic enhanced scan, concentration of350mg I/ml contrast medium wasinjected; group B contained38cases using low concentration of contrast medium inoptimal monochromatic parameters scan group, followed by routine tri-phase totalabdominal scan using spectral CT imaging injected concentration of270mg I/ml contrast medium. The images of two groups were reconstructed and evaluated by tworadiologists using5-scale score. The inter observer agreement was evaluated by Kappaand subjective rating were compared by Mann-Whitney U. CT HU value, imagenoise, contrast-to-noise ratio (CNR) and CT dose index(CTD Ivol）were compared byindependent sample t test.Results: The the optimal monochromatic of group B were51～60keV. The interobserver agreement for subjective scores is very good (Kappa value>0.80); ICC (ICCvalue>0.75). Subjective image quality scores, CT HU values, image noise, CNR andCTDIvol of high concentration group and low concentration group were2.64±0.86points and3.53±0.69points,242.80±41.44HU and408.41±50.72HU,21.03±2.66HUand18.67±2.18HU,8.95±2.51and18.60±2.17. The differences were statisticallysignificant (P <0.05). The CTDIvol of two groups were17.84±4.68mGy and16.87±0.00mGy respectively, the differences was no statistically significant (P=0.205).Conclusion:The low concentration contrast medium optimal monochromatic mode canimprove CTA quality of small tumor blood supply arteries of gastrointestinal tractmalignant tumors with GSI technique using single source dual-energy CT，and theradiation dose not increase．...