EP1.11-08 Ultra-High-Resolution CT to Project the Detailed Components in Nodules; Fat Components in Pulmonary Hamartomas

Abstract

The purpose of this study was to evaluate the utility of the detailed matrix of ultra-high-resolution CT (UHRCT) to detect the detailed attenuation heterogeneity in pulmonary hamartoma which contains fat component. Seven consecutive patients (three males, four females; 48-73 y.o.) with pulmonary hamartoma who underwent UHRCT were enrolled retrospectively. Each patient’s hamartoma was diagnosed by using bronchoscope, surgical therapy or follow up study. All CT studies were performed by using ultra-high-resolution CT machine (Aquilion Precision; Canon Medical Systems, Otawara, Japan). All CT examinations were performed with 160-detector row CT scanner; 120kVp, auto-mAs, 1792 channels, collimation 0.25 mm x 160 rows, 1024 matrix. Conventional high-resolution CT (HRCT) images were reconstructed with 1mm slice, 1mm interval, 512 x 512 matrix. Ultra-high- resolution CT (UHRCT) images were reconstructed with 0.25 mm slice, 0.25 mm interval, 1024 x 1024 matrix. The CT densities of each hamartoma were measured by placing ROI at the longest diameter of the nodule on CT image. The lowest densities in the nodule were statistically compared between on HRCT and UHRCT by using paired t-test. P value less than 0.05 was considered to be significant. The average minimum densities of hamartomas on HRCT and UHRCT were -39.1 and -65.0, respectively (p = 0.092). The lowest densities of hamartomas were lower on UHRCT than on HRCT, not significantly. The UHRCT’s smaller voxel may reveal the detailed heterogeneity in the nodule to detect fat component of hamartoma.