Multidetector helical CT technology permits high-speed and high-resolution imaging data of the entire thorax to be acquired during a single breath-hold [1-3]. The lungs can be scanned in 12 sec with four detectors, each with collimation of 2.5 mm, or in 24 sec if 1.25-mm collimation is used [1-3]. Even faster systems are being developed [4]. State-of-the-art equipment already provides an almost cuboidal voxel size of about 1 X 1 X 1.25 mm. Thus, reconstructed nonaxial images have a resolution comparable with that of the best axial images [1-3].
The diagnostic value of high-speed CT can be enhanced by using the original axial helical CT data set to construct a new set of planar reconstructions arranged in a "paddle-wheel" pattern, in which all planes pass through a central horizontal axis between the two lungs and hilum. In this article, we introduce the paddle-wheel CT imaging method.