High-resolution CT using multidetector CT equipment: Evaluation of image quality in II cadaveric lungs and a phantom

OBJECTIVE. The aim of this study was to evaluate the image quality and diagnostic efficacy of multidetector high-resolution CT (HRCT) by comparing it with single-detector HRCT and by comparing the noise and artifact of multidetector HRCT images with a phantom. SUBJECTS AND METHODS. Multidetector HRCT with six parameters and single-detector HRCT were performed on cadaveric lungs. The image. quality and diagnostic efficacy of multidetector HRCT were evaluated in comparison with those of single-detector HRCT. A phantom was scanned, and image artifact and noise were investigated. RESULTS. The image quality of multidetector HRCT with axial 1.25 mm x 4i (four images per gantry rotation) mode was equal to that of single-detector HRCT. The image quality of multidetector HRCT with other modes was worse than that on single-detector HRCT. The diagnostic efficacy of multidetector HRCT with high-quality mode (pitch, 3:1) and axial mode was equal to that of single-detector HRCT. The diagnostic efficacy on multidetector HRCT with high-speed mode (pitch, 6:1) was worse than that on single-detector HRCT. In the phantom study, images made in high-speed mode had strong artifacts. Noise in the axial mode was milder than that in high-speed mode but more severe than that in high-quality mode. CONCLUSION. The image quality of axial HRCT with multidetector CT is equal to that on single-detector HRCT. Axial HRCT with multidetector CT is appropriate for evaluating subtle lung abnormalities, but high-speed mode is unsuitable. Using the high-quality mode degrades image quality but is still worthwhile.