Spectral CT In Ovarian Tumor Targeting The Application Of Qualitative Research

Part One Clinical value of ovarian artery image quality with spectral CT monochromatic imaging and adaptive statistical iterative reconstruction techniqueObjective:To investigate the clinical value of spectral CT monochromatic imaging and adaptive statistical iterative reconstruction technique on the image quality of ovarian artery.Materials and Methods:The institutional review board of the first affiliated hospital of Zhengzhou university approved this prospective study;all patients provided written informed consent.From August 2015 to December 2016,64 female patients(age range 20~82,median age 51.30)who had pelvic occupied lesion underwent abdominal contrast enhanced CT were randomly assigned into the control group(n=32)and study group(n=32).The control group scanned with 120 k Vp tube voltage and the images reconstructed with 40% ASIR.The study group scanned with gemstone spectral imaging(GSI)(GE Discovery CT),and the spectral monochromatic images 40 ~ 70 ke V(intervals of 5 ke V,7 levels)were reconstructed with 30~60% ASIR(5 levels) respectively.The CT value of the ovarian artery and the psoas major in the same layer and the standard deviation of the CT value of the subcutaneous fat in the same side of the same layer were measured in arterial.The contrast-to-noise ratios(CNR)and signal-to-noise ratios(SNR)of ovarian artery were calculated.Using single factor analysis of variance to compare experimental objective evaluation index(CT、SNR、CNR),Using LSD method to compare between the tow groups.Independent samples t test was used to compare the objective evaluation index,age and effective radiation dose of the two groups.Two radiologists independently and blindly assessed the subjective image quality.The results were analyzed with one-way analysis of variance,Mann-Whitney U test.Results:There was no significant difference in age and ED(m Sv)between the control group and the experimental group(the control group :53.78±14.15、9.80±1.51,the test group 48.81±17.29、10.84±3.55,all P>0.05).With the increase of single energy level,the CT value of ovarian artery decreased gradually.CT values of ovarian artery decreased with the monochromatic imaging.Ovarian artery CNR and SNR at 40 ke V reconstructed with 60% ASIR(26.12±7.92、30.45±8.13)reached the maximal,and higher than that at 120 k Vp reconstructed with 40% ASIR(3.29±5.44、18.67±5.61)(all P<0.05).At 40 ke V reconstructed with 50% ASIR(4.18±0.63)yielded a maximal subjective image quality score,similar scores to that at 40 ke V reconstructed with60% ASIR(4.12±0.64).Conclusion:Spectral CT monochromatic imaging and adaptive statistical iterative reconstruction technique can optimize the image quality of ovarian artery at 40 ke V reconstructed with 60% ASIR,without radiation dose increasing,which is of great benefit to the clinical diagnosis and treatment.Part Two Value of Spectral CT imaging in the differential diagnosis of benign and malignant ovarian tumorsObjective:To investigate the CT spectral imaging features of benign and malignant ovarian tumors and to assess the value of spectral CT in differentiating between benign and malignant ovarian tumors.Materials and Methods:The institutional review board of the first affiliated hospital of Zhengzhou university approved this prospective study;all patients provided written informed consent.From August 2015 to December 2016,98 female patients(age range 12~84,median age 45.01)with ovarian tumor confirmed by pathology underwent preoperative pelvic or abdominal CT scanning that included arterial phase(AP)and venous phase(VP)with GSI mode.Divided into two groups according to the difference of cystic or solid components,the first group of cystic components of ovarian tumors,a total of 64 cases(32 benign,32malignant),the second group of solid components of ovarian tumors,a total of 34 cases(11 benign,23 malignant).The spectral monochromatic images at 70 ke V were reconstructed with40% ASIR.Measurements were performed on the GSI viewer.The iodine concentration(IC,100ug/cm3)、the water concentration(WC,mg/cm3)and the calcium concentration(CC,mg/cm3)of cystic or solid components of ovarian tumor and the iodine concentration of iliac artery in the same layer in two groups of double phase were saved,the normalized iodine concentration(NIC)and the slope of spectral curve were recorded.NIC=the iodine concentration of ovarian tumor /the iodine concentration of iliac artery,k=(CT attenuation(40ke V)-CT attenuation(100ke V))/60.The spectrum parameter were compared of benign and malignant ovarian tumor by independent sample t-test with software SPSS 21.0.Receiver operating characteristic(ROC)was used to determine the diagnostic efficiency of the corresponding parameters.Results:The age of malignant ovarian tumor(49.33 ± 13.57)was higher than that of benign ovarian tumor(39.49±14.18),and the difference was statistically significant(P<0.01).The iodine concentration、the calcium concentration 、the slope of spectral curve and the normalized iodine concentration of cystic components of malignant ovarian tumor were 3.63±1.70(100μg/cm3)、5.21±2.47(mg/cm3)、0.05±0.02、0.43±0.20 in AP and 3.81±1.62(100μg/cm3)、5.44±2.25(mg/cm3)、0.04±0.01、0.45±0.19 in VP,the iodine concentration、the calcium concentration 、the slope of spectral curve and the normalized iodine concentration of benign ovarian tumor were2.08±0.84(100μg/cm3)、2.92±1.25(mg/cm3)、0.03±0.02、0.25±0.10 in AP and2.58±1.22(100μg/cm3)、3.66±1.80(mg/cm3)、0.03±0.01、0.31±0.14 in VP,and he difference was statistically significant(all P<0.01).The specificity of each parameter in the arterial phase was higher than in the venous phase,and the sensitivity was higher in the venous phase than in the arterial phase.The iodine concentration、the slope of spectral curve and the normalized iodine concentration of solid components of malignant ovarian tumor were 14.50 ± 6.44(100μg/cm3)、0.33±0.12、1.72±0.77 in VP,the iodine concentration、the slope of spectral curve and the normalized iodine concentration of benign ovarian tumor were8.86 ± 4.04(100 μ g/cm3)、 0.22 ± 0.13 、 1.05 ± 0.48 in VP,and he difference was statistically significant(all P<0.01).AUC of the normalized iodine concentration was the largest.Conclusion:There was a significant difference of spectral CT characteristics between benign and malignant ovarian tumors.GSI scan mode can provide novel information for the differential diagnosis between benign and malignant ovarian tumors.