A Study Of Spectral CT Parameters Combined With Morphological Characteristics Valuation In The Differential Diagnosis Of Pulmonary Nodules/Masses

Objective:To explore the value of spectral CT parameters combined with morphological characteristics in differentiating diagnosis of pulmonary nodules/masses.Methods:70 patients with pulmonary nodules/masses were included and underwent with GE Discovery 750HD CT machine,including a conventional scan and dual-phasic contrast-enhanced dual-energy spectral scans(GSI).In AW4.6 workstation,measuring the CT values for each single-energy(interval 10 keV)and iodine(water)content of the arterial and venous phase,and calculating 40?70 keV slopes of spectral curves and the normalized iodine(water)concentration.All of datas were measured three times and the mean value was calculated.At the same time,two radiologists with more than 5 years working experience analyzed the morphological characteristics of pulmonary nodules/masses.The comprehensively scores were recorded.When the opinions were inconsistent,an agreement was reached through consultation.The two radiologists had no knowledge of clinical information and pathology beforehand;the statistical analysis were performed to compare morphological comprehensively scores,parameters of spectral CT and morphological comprehensively scores combined with parameters of spectral CT.The ROC curve was used to evaluate the value in differentiating diagnosis of pulmonary nodules/masses.Results:In 70 cases.35 patients were confirmed by pathology or follow-up.19 were malignant and 16 were benign.The comprehensively scores of malignant group(3.84±1.18)were significantly higher than that of benign group(2.06±1.05)(P<0.05).When the diagnostic threshold was set as 3.25,the sensitivity,specificity and accuracy were 68.4%,93.7%and 80%,respectively.The CT values of 40keV,CT values of 70keV,IC,NIC and slope rate of spectral curve of malignant group were significantly higher than that of benign group(P<0.05).When the diagnostic threshold of NIC was set as 0.282,the sensitivity,specificity and accuracy were 89.5%,68.7%and 80%,respectively.Combining morphological characteristics comprehensive scores with parameters of spectral CT,the sensitivity,specificity and accuracy were higher.Especially when the morphological characteristics comprehensive scores combined with venous phase NIC value,the sensitivity,specificity and accuracy were 84.2%,81.3%,82.9%,respectively.Conclusion:The sensitivity of using morphological features alone to diagnose pulmonary nodules/masses is low.Parameters analysis of spectral CT can help differentiate malignant pulmonary nodules/masses from benign,but the specificity is low.When the morphological comprehensive scores combined with venous phase NIC value.the sensitivity,specificity,accuracy,positive predictive value and negative predictive value of the diagnosis of pulmonary nodules/masses were both high,and develop the advantage of using morphological features or parameters analysis of spectral CT alone.