Analysis of Correlation between CT Features of Phase III Pneumoconiosis and Silica Content in the Lungs

Objective: By using Siemens dual-source CT dual-energy scanning technique, To measure the content of silicon dioxide (SiO₂) and the mixed-energy CT value in the tissues of phase III Pneumoconiosis patients, and to find the relationship between the content of SiO₂, the main CT features and its deposition site. Results: The content of SiO₂ in lung tissue of Pneumoconiosis group was (0.57±0.49) mg/mL, the healthy control group was (0.26±0.20) mg/mL, the mixed energy CT in Pneumoconiosis group was (-777.72±111.33) HU, the healthy control group was (-829.95±112.31) HU. The content of SiO₂ and CT value of mixed energy in Pneumoconiosis group were higher than those in healthy control group. There were significant differences between the two groups (P=0.00).Comparing the SiO₂ content and the mixed energy CT values between different deposition sites in the Pneumoconiosis group, the highest level was the lower 3cm level of tracheal bifurcation group, the lower edge of tracheal bifurcation group was in the middle, the lowest one was the distal of the aortic arch level group. The results showed that there was significant difference between the three levels. The SiO₂ was mainly distributed in two lower lung fields in patients with Pneumoconiosis phase III, and it was decreased gradually from the base to the top. Comparing the relationship between the complexity of the CT features and the content of SiO₂ as well as the mixed energy CT values, the content of SiO₂ and the mixed energy CT values were the highest in people have five CT manifestations group, with the mean values of (0.72±0.58) mg/mL and (-719.30±154.68) HU. The lowest was found in people only have one CT manifestations group, with the mean values of (0.49±0.40) mg/mL and (-809.74±105.60) HU. The result was that the more complex of the CT features in Pneumoconiosis phase III patients, the higher the SiO₂ content and the mixed energy CT value inside. Conclusion: Dual-source CT dual-energy scanning can quantitatively evaluate the amount of SiO₂ and the mixed energy CT value in the lung tissue. The content of SiO₂ is positively correlated with mixed energy CT value; moreover the content and CT value are related to the location of silica deposition and the main CT manifestations.