Objective: To observe the diagnostic efficiency of gemstone spectral CT imaging in diagnosis of solitary pulmonary nodule (SPN).
Methods: A total of 114 patients with SPN proved by pathology (from the First Affiliated Hospital of Zhengzhou University and 13 cooperative hospitals) underwent spectral CT from July 2014 to July 2015.All the patients were divided into malignant group(63 cases), inflammatory group(32 cases) and tuberculosis group(19 cases) .Iodine concentration(IC), normalized iodine concentration(NIC) and slope rate of spectral curve(40-80 keV) in both arterial and venous phase were measured and calculated.The one-way ANOVA and LSD were used to analyze parameters among 3 groups.ROC curves were taken to calculate the diagnostic efficiency and the diagnostic sensitivity and specificity .
Results: IC, NIC and slope rate of spectral curve had statistically significant differences in both phases (all P<0.05). The malignant group was the highest, and the tuberculosis group was the lowest(all P<0.05). When NIC(venous phase)>0.31, NIC>0.28, NIC>0.21, the sensitivity of diagnosing malignant and inflammatory SPN, malignant and tuberculosis SPN, inflammatory and tuberculosis SPN were respectively 81.0%, 85.7%, 84.4%, and the specificity of them were 71.9%, 94.7%, 84.2%, respectively.
Conclusion: Spectral CT imaging is helpful to diagnosis of SPN, and venous phase NIC can get high sensitivity and specificity for qualitative diagnosis of SPN.