The Value Of Spectral CT Imaging In Differentiating Gastric Antrum Cancer And Ulcer

Objective： In order to evaluate Gemstone Spectral Imaging in differentiation anddiagnosis of gastric antral cancer and ulcer, There were effective atomic numbers,Gemstone Spectral Imaging slope curves (K values) and various parameters duringenhanced scan and triple-phase-contrast-enhanced scans had been analyzed.Materials and Methods：Forty-six patients with advanced gastric antral cancer andulcer were identified via Gemstone Spectral Imaging CT imaging and verified by gastricbiopsy histopathology in our hospital were retrospectively analyzed, from December2012to December2013There were30gastric antral cancer cases and16gastric antralulcer ones in the research. Via Gemstone Spectral Imaging viewer(GSI viewer).wemeasured CT values for menoenergetic keV40～140keV, iodine(water),water(iodine),fat (water), water(fat) concentrations and effective atomic numbers of gastric antralcancer and ulcer. To compare the data of the above parameters and analyze them withSPSS17. If it is in accord with normal distribution, we did t test for two independentsamples. If not, we did rank sum test. To pick out data(P＜0.05) and analyze ROC’sthreshold values, sensitivity, specificity and Area Under Curve（AUC）. To measure andcalculate the slope of Gemstone Spectral Imaging curves and compare their diagnosisefficiencies.Results：1)In enhanced scanning, under monoenergetic40、50keV, the difference of CTvalues between two groups was significant different.. CT values of gastric antral cancerwere higher than those of gastric antral ulcer (P＜0.05).Under40KeV and60～140KeV, the difference between the two groups was no significant different,(P＞0.05). In arterialphase, under monoenergetic40～80KeV, the difference of CT values between twogroups had remarkable statistical significance(P＜0.05). CT values of gastric antralcancer were higher than those of gastric antral ulcer. Under monoenergetic90～140KeV,there was tiny difference between two groups，and no statistical significance (P＞0.05).In venous phase, under monoenergetic40～140keV, there was statistically significantdifference(P＜0.05). CT values of gastric antral cancer were higher than those of gastricantral ulcer(P＞0.05). In contract of diagnostic efficiencies in different periods, it washigher in venous phase, AUC=0.981; general in arterial and delayed phases,AUC=0.773, AUC=0.821, respectively; lower in enhanced scanning, AUC=0.673.2)Intriple-phase-contrast-enhanced scans, effective atomic numbers of gastric antral cancerwere higher than those of gastric antral ulcer. And in venous phase, in gastric antralcancer while in gastric antral ulcer，a very big difference，statistical significant(P＜0.05);in enhanced scanning, no significant difference(P＞0.05).3)In contract of standardsubstances in enhanced scanning and triple-phase-contrast-enhanced scans, iodine（water）concentrations of gastric antral cancer was higher in arterial, venous anddelayed phases, showing statistically significant difference. And in venous phase, therewas a remarkable and statistically significant difference(P＜0.05) In contract ofdiagnostic efficiencies in different periods, it was higher in venous phase, AUC=0.944;general in arterial and delayed phases, AUC=0.743, AUC=0.782, respectively. Nodifference in water（iodine）concentrations between gastric antral cancer and ulcer,(P＞0.05). In plain scanning,The mean value of fat (water) in gastric antral cancer wassignificant lower than that of gastric antral ulcer(P＜0.05).The AUC for differentiationbetween these two groups was0.726.The mean value of water (fat) was significanthigher than that of gastric antral ulce(P＜0.05).The AUC for differentiation betweenthese two groups was0.734.4)In contract of slope of curves (k value), it was higher ingastric antral cancer in arterial, venous and delayed phases, among which, it was highestin venous phase，respectively. In contract of diagnostic efficiencies in different periods,it was higher in venous phase, AUC=0.889; lowest in arterial phase, AUC=0.698; general in delayed phases,AUC=0.726.Conclusion：In venous phase, different spectral features exist in individual energyvalues, effective atomic numbers, iodine（water）concentrations, Gemstone SpectralImaging slope curves (K values),fat (water) and water (fat) concentrations in plainscanning between gastric antral cancer and ulcer. That helps to identify and diagnosethem. Especially in venous phase,the difference of CT values and iodine（water）concentrations between two groups were significant different. They had the mostdiagnostic significance.