Texture-based CT Image Analysis of Asthma

摘要

This study was motivated by anecdotal reports from our clinicians that the lung parenchyma appears "different"(more heterogeneous)in asthmatics compared to non-asthmatics. We investigated whether traditional texture features were different between severe asthmatics and non-asthmatics. CT examinations from 76 subjects classified as "severe asthma"(n= 51)and "normal control"(n= 25)based on Severe Asthma Research Program(SARP)criteria were used in this study. The CT exams were performed on a 64-detector or 16-detector GE scanner at a radiation exposure of 96.6(±30.7)mAs with the subjects holding their breath at end-normal-expiration(functional residual capacity). The CT images were reconstructed at 0.625 or 1.25 mm thickness using either GE's "standard" or "detail" kernels. Air trapping was computed as the percentage of voxels with a value less than -856 HU. Gray level co-occurrence matrices(GLCM)were computed from the CT images, and 15 Haralick texture descriptors were computed from the GLCM. Air trapping was significantly greater in the severe asthma subjects compared to the normal control subjects. Seven of the 15 texture features were significantly different between the severe asthma and normal control subjects. Our findings provide some validity to anecdotal reports of differences between the parenchyma of asthmatic and non-asthmatics. The significant texture features may ultimately be used to classify individuals as asthmatic or non-asthmatic, which should improve the limited performance of air trapping alone.