Improved delineation of CT virtual bronchoscopy by ultrahigh-resolution CT: comparison among different reconstruction parameters

Abstract

Abstract Purpose We compared the maximal recognizable bronchial bifurcation order (MRBBO) in CT virtual bronchoscopy (CTVB) using ultrahigh-resolution CT (UHRCT) and different reconstruction parameters. Materials and methods We enrolled 38 patients undergoing noncontrast chest CT by UHRCT and reconstructed CTVB utilizing 3 different combinations of reconstruction parameters, as classified into Group A (matrix size, 512; slice thickness, 1.0 mm), Group B (matrix size, 512; slice thickness, 0.5 mm), and Group C (matrix size, 1024; slice thickness, 0.25 mm). In right S1, left S1 + 2, and both S3 and S10, two reviewers counted the number of consecutively identified bronchial bifurcations to compare MRBBO among these groups using Kruskal–Wallis test. Results In these segments, MRBBO increased from Group A to C. MRBBO was significantly higher in Group C than in both Groups A and B in all the segments except left S10 (P < 0.05 for all). In left S10, it was significantly higher in Group C than in Group A (P < 0.05) but comparable between Groups B and C (P = 0.122). Conclusions MRBBO is higher in CTVB by UHRCT utilizing 1024-matrix size and 0.25-mm thickness than parameters currently recommended for CTVB (matrix size, 512; slice thickness, 0.5–1.0 mm).