A Study Of Dual-source CT Perfusion Imaging Assessing Micro-Vascular Composition In Solitary Pulmonary Nodules

Objective: The purpose of this study was to explore the correlation between dual-source computed tomography perfusion imaging(CTPI)with microvessel density(MVD)and luminal vascular parameters and evaluate the value of CTPI in the differential diagnosis of solitary pulmonary nodules(SPNs).Methods: eighty-one patients with SPNs who successfully underwent pre-operative CT perfusion imaging with dual-source CT and received a final diagnosis by pathology between January 2015 and November 2017 were enrolled.The cases including 50 males and 31 females,aged from 23 to 74 years,with a mean age of51.27 years.The corresponding time-density curve(TDC),perfusion pseudo-colour images and perfusion parameters,such as blood flow(BF),blood volume(BV),mean transit time(MTT)and permeability surface(PMB),were obtained by performing a40-second volume perfusion computed tomography of the SPNs.After the surgery,the SPN specimens were immunohistochemically stained for CD34 and SMA to determine the corresponding MVD,luminal vascular parameters(LVN,LVA,LVP)and LVN/MVD,respectively.The patients were divided into malignant,benign,and inflammatory groups according to the pathological results,including 20 cases of benign SPN,16 cases of inflammatory SPN and 45 cases of malignant SPN.All data were statistically analysed.The differences of dual-source CT perfusion parameters,MVD,luminal vascular parameters and LVN/MVD among the three groups was observed;The correlation analysis was used to study the relationship between dual-source CT perfusion parameters and MVD,luminal vascular parameters and LVN/MVD;Then ROC curve was used to analyze the diagnostic efficiency of dual-source CT perfusion parameter as the diagnostic index of malignant SPN.Results:(1)Benign SPN mainly showed ? type curve(a slight upward trend and fluctuations in a certain range),accounting for 75%(15/20).Inflammatory SPN mainly showed ? type curve(rapid rise and slow decline type),accounting for 62.5%(10/16).Malignant SPN mainly showed ? type curve(rapid rise and immediate decline type,the descending part with the platform),accounting for 64.4%(29/45).(2)The BF,BV,MVD,luminal vascular number(LVN),luminal vascular area(LVA),and luminal vascular perimeter(LVP)values in the benign groups were significantly lower than those in the malignant and inflammatory group(P<0.05).A significantdifference was observed in the PMB,LVN/MVD,LVA and LVP between the malignant group and inflammatory group(P<0.05),but no significant difference was observed in the BF,BV,MVD and LVN between the two groups(P>0.05).(3)BF and BV were positively correlated with the MVD,LVN,LVP,and LVA,and the correlation between BF and BV and the luminal vascular parameters(LVN and LVA)was stronger than that with MVD.The PMB was associated with the LVN/MVD,LVN,LVA,and MVD(P<0.05),and the correlation between the PMB and LVN/MVD was the most relevant.MTT has correlation with MVD and LVN(P<0.05).(4)Using BF?56 ml/100 ml/min,BV?6.33 ml/100 ml/min or PMB?9.85 ml/100 ml/min as the cut-off point to predict the malignant SPNs,the sensitivity was 82.2%,82.2%,and97.7%,and the specificity was 66.7%,58.3%,and 58.3%,respectively.Using BF?44ml/100 ml/min,BV?6.00ml/100 ml and PMB?9.26 ml/100 ml/min for the diagnosis,the area under the curve(AUC)of the receiver operating characteristic(ROC)curve was 0.760.The sensitivity was 82.2%,and the specificity was 72.2%,the diagnosis coincidence rate is 77.8%.Conclusions: Significant differences were observed in the microvascular composition among the benign,inflammatory and malignant SPNs.The correlation between the CT perfusion parameters and luminal vascular parameters was stronger than that between the CT perfusion parameters and MVD.Thus,dual-source CT perfusion can be used as an important index to non-invasively evaluate tumour angiogenesis.Dual-source CT perfusion imaging is conducive to the diagnosis and differential diagnosis of SPNs.