Feasibility Study On Evaluation Of Differentiation Degree Of Malignant Solitary Pulmonary Nodules By CT Energy Spectrum Curve

Purpose:Despite a higher detection rate of solitary pulmonary nodules(SPN) before the operation,identification of differentiation is still more difficult. The main purpose of this study to evaluate the application value of CT spectrum curves in the differential diagnosis of SPN differentiation, for clinical further applying the technology and providing the basis. Materials and Methods:Collecting 37 patients(in our hospital and 13 sub Central Hospital) who accepting the spectral CT imaging dual enhancement scan, all patients were confirmed by pathology but without treatment, according to the degree of pathological differentiation all patients are divided into three groups of low, medium and high differentiation. All data were transferred to AW GE 4.6 post-processing station, the energy spectrum attenuation characteristic curve of the lesion was obtained by Viewer GSI post processing software. According to the single energy CT value of lesions in arterial phase and venous phase at 40 ke V, 80 kev and 140 kev, calculating and comparing the absolute value of slope of characteristic curve in different energy segment internal energy attenuation spectrum. At the same time, using the ROC curve to evaluate the diagnosis efficiency of the curve slope of different energy segment energy attenuation spectrum characteristics and calculating the diagnostic sensitivity and specificity. Results:Among all 37 cases, 18 cases were poorly differentiated, 13 were moderately differentiated, 6 were highly differentiated. The single energy CT value of the lesions showed similar trend with the decrease of X-ray energy level, all of which showed that the slope of the attenuation characteristic curve was negative. As the single ke V energy values decrease gradually and the corresponding attenuation characteristic curve contorts slightly flat; and when the single ke V energy value is increased, the corresponding attenuation characteristic curves were steeper. The low differentiation SPN was only in the slope of the energy spectrum attenuation characteristic curve at 40 ~ 80 ke V, and the slope of the energy spectrum attenuation characteristic curve was statistically significant(P<0.05) in the differentiation SPN and the highly differentiated SPN. And the lesions of segmental high energy attenuation characteristic curves were compared, decay of lesions in the low energy section feature curve slope difference compared with arterial phase slightly larger, the difference is statistical significance(P < 0.05) and in 40 to 80 ke V energy segment difference is most evident(P < 0.05). Diagnostic sensitivity and specificity of 40 to 80 ke V energy Festival period spectral attenuation characteristic curve slope in the identification of different degree of differentiation SPN diagnosis efficiency and arterial phase between the groups choose diagnostic sensitivity and specificity of the optimal threshold respectively can reach above 80%, venous phase selection optimal threshold were up to 70% above. Conclusion:The slope of the energy spectrum attenuation characteristic curve of SPN with different differentiation degree was different, which had a certain reference value for the choice and prognosis of malignant SPN treatment.