| Part1:The Application Value of CARE kV Technique in Lung Cancer ScreeningObjective:To evaluate the performance of CARE kV technique combined with SAFIRE reconstruction on radiation dose saving and image quality in lung cancer screening.Methods:Between August 2015 and October 2015,a consecutive series of 200 participants were recruited and randomized into two groups.Two chest CT scans were performed with current time product of 40 m As at 120 kVp(control group),and 60 m As with CARE kV technique(experimental group),respectively.Both SAFIRE and FBP reconstruction algorithms were applied to two groups.CT dose index of volume(CTDIvol),dose length product(DLP)and effective dose(ED)were recorded.Mean CT value,image noise(SD)and signal-to-noise ratio(SNR)were measured in aortic root level.Subjective scores of image noise,images artifacts and the overall image quality were assessed by two radiologists,and results of two groups were compared.Results:There was no significant difference in the mean weight and the body mass index between experimental and control groups(68.24±11.07 vs 67.78± 10.86 Kg;23.75±2.82 vs 23.62±2.96;P>0.05,P>0.05,respectively).The radiant dose of experiential group was lower than that of control group(CTDIvol,1.70±0.16 vs 2.17±0.32 m Gy;DLP,59.07±9.40 vs 73.67±10.54 m Gy*cm;ED,0.84±0.13 vs 1.03±0.15 m Sv;all P<0.05)..Experimental group showed lower SD and higher SNR(SD,6.38±1.75 vs 7.05± 2.14;SNR,6.96±1.31 vs 5.25±1.37;P<0.05).All of the images could satisfy diagnosis requirement.Conclusion:CARE kV technique combined with SAFIRE reconstruction shows high value in reducing the radiation dosage and improving image quality simultaneously in lung cancer screening.Part2:The qualitative diagnostic value of vascular invasion in ground glass nodulesObjective:To evaluate the qualitative value of vascular invasion in ground glass pulmonary nodules.Methods:Chest contrast-enhanced dual-source CT scans were reviewed retrospectively for ground glass pulmonary nodules(GGN)in 136 patients with surgical treatments.One hundred and thirty-six ground glass pulmonary nodules(diameter 5-20mm)were recruited,including 20 benign nodules and 116 malignant nodules,which consisted of 32 pre-invasive lesions(PL),31 minimally invasive adenocarcinoma(MIA),and 53 invasive adenocarcinoma(IA).Vascular invasions were classified into pulmonary artery invasion(type I)and pulmonary vein invasion(type II).Chi-square test or exact probability method was performed to evaluate the difference in vascular invasion.Results:Vascular invasion was found in 73 of all the 136 GGNs(53.68%),with 6 benign(30.00%)and 67 malignant GGNs(57.76%),respectively.Significant higher frequency of vascular invasion was found in malignant GGNs(P=0.021).The incidence of type II in malignant GGNs was significantly higher than that in benign GGNs(43.97% [51/116] vs 20.00% [4/20],P = 0.044).With the increased infiltration degree,the incidence of type II increased(PL 21.88% [7/32],MIA25.81% [8/31],IAC67.92% [36/53]).Significant differences in the incidence of type II were found between IAC and MIA(P <0.001),as well as between PL and MIA(P <0.001),but not between PL and MIA(P = 0.714).As for type I,there was no significant difference neither between benign and malignant GGNs(10.00% [2/20] vs 13.79% [16/116],P = 0.644),or among malignant nodules [PL 12.50%(4/32),MIA25.81%(8/31),IAC7.55%(4/53),all P>0.05].Conclusions:Vascular invasion shows potential value in the differentiation between benign and malignant GGNs.The presence of pulmonary vein invasion in GGNs indicates the high risk of invasive adenocarcinoma. |
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