The value of spectral CT in differentiating benign and malignant serous cavity effusion in vitro

Abstract

Objective To assess the value of spectral CT in differentiating benign and malignant serous cavity effusion in vitro. Methods 41 plastic tubes filled with serous cavity effusion underwent spectral CT imaging.The gemstone spectral imaging(GSI) viewer was used to measure the mean CT values of water-iodine concentration, iodine-water concentration, monochromatic images(40-140KeV, interval of 5KeV), 140KVp QC, and EFF-Z.Slope of spectral curve was measured also.Based on clinical and pathological diagnosis, 30 cases of benign and 11 cases of malignant serous cavity effusion were compared.The difference of the spectral characteristic parameters was evaluated statistically by independent-samples t test using SPSS 18.0. Results The EFF-Z, water-iodine concentration, iodine-water concentration, and slope of spectral curve[7.26±0.25, (1 021.82±6.37)mg/mL, (-3.23±1.53)mg/mL, 0.26±0.12] of benign serous cavity effusion showed no statistically significant differences between the malignant group[7.31±0.10, (1 016.17±5.32)mg/mL, (-3.06±1.18)mg/mL, (0.24±0.10), t=0.652, 2.016, 0.332, 0.482, all P>0.05]. There were statistically significant differences on 55-140 KeV between the two groups[(4.87±7.13) and (10.66±6.70), (7.17±6.48) and (12.71±5.94), (9.58±6.11) and (14.96±5.65), (11.63±5.97) and (16.77±5.52), (13.31±5.93) and (18.36±5.52), (14.66±5.98) and (19.52±5.52), (16.06±6.06) and (20.90±5.63), (17.03±6.10) and (21.42±5.88), (17.58±6.12) and (22.29±5.59), (18.05±6.14) and (22.74±5.49), (18.52±6.17) and (23.19±5.51), (18.74±6.20) and (23.33±5.46), (19.16±6.20) and (23.80±5.47), (19.30±6.26) and (23.87±5.45), (19.57±6.26) and (24.19±5.48), (19.66±6.28) and (24.21±5.43), (19.92±6.31) and (24.46±5.44), (20.00±6.32) and (24.53±5.43), t=2.339, 2.474, 2.544, 2.489, 2.456, 2.356, 2.301, 2.060, 2.231, 2.223, 2.206, 2.161, 2.188, 2.138, 2.162, 2.122, 2.114, 2.104, all P 0.05]. The difference between benign and malignant effusion was statistically significant on 140KVp QC also [(10.25±6.96, 16.60±6.84)(t=2.601, P=0.013)]. Conclusion Some spectral CT characteristic parameters especially 55-140 KeV monochromatic images can differentiate benign and malignant effusion.Spectral CT maybe afford a new method to differentiate benign and malignant effusion. Key words: Spectral CT; Serous cavity effusion; Malignant; Benign; Monochromatic