Multi Slice Computed Tomography in the study of pulmonary metastases

Purpose. This study was undertaken to assess the performance of 16-slice computed tomography (MSCT) using Multi-Planar Reformatting (MPR), Maximum Intensity Projection (MIP) and Volume Rendering (VR) reconstructions to study pulmonary metastases. Materials and methods. CT studies of 32 patients with pulmonary metastases were retrospectively reviewed. Images were assessed for the following parameters: number, size, location, distribution of the nodules and the presence of the "mass-vessel sign". These parameters were evaluated by two observers on axial-source images and on MPR, MIP and VR reconstructions. Sensitivity of each reconstruction and interobserver agreement were calculated. Results. Two-dimensional (21)) axial images and MIP and VR reconstructions exhibited 100% sensitivity for lesions > 10 mm. For nodules 6-10 mm, sensitivity was 49%-55% for the 2D images, 90% for MIP and 80%-85% for VR reconstructions. For metastasis :! 5 mm, sensitivity was 22% for 2D images, 87%-89% for MIP and 55%-58% for VR reconstructions. Coronal and sagittal MPR, MIP and VR did not improve the detection rate compared with the corresponding axial images. MIP and VR provided overlapping results in detecting the "mass-vessel sign". Conclusions. MIP are the most sensitive reconstructions for detecting small pulmonary nodules.