High-resolution three-dimensional imaging from subsecond helical CT data sets: applications in vascular imaging.

Abstract

T he coupling of three-dimensional (3D) imaging with helical CT data sets has shown promise in a wide range of clinical applications in the chest, abdomen, CNS, and vascular systems [ 1 , 2]. The potential ability to create vascular maps is a particularly exciting area, with initial results suggesting that for specific applications, 3D CT could replace conventional angiography [1-3] at a considerable savings in both cost and potential morbidity. Numerous articles have attempted to address the importance of data acquisition protocols with a focus on the role of slice thickness and pitch and the inevitable compromises in parameter selection [2-4]. Other articles have focused on the technical aspects of the 3D reconstruction process, with the advantages and disadvantages of shaded surface display, maximum intensity projection, and volume-rendering technique debated in the literature [4]. One of the most recent advances has been the subsecond scan time capability of helical CT scanners. These scan times, which are in the range of 0.75 sec. do not reach the 100msec acquisitions of the so-called ‘fast scanners” (Electron Beam Scanner; Imatron, Oyster Bay, CA). However, they do provide the capability of even fasten slice acquisition and better volume data sets. Herts et al. [5] compared image quality of helical CT scans in which times of acquisition were 0.75 sec and 1 sec. These authors found little perceived difference for measures of organ edge sharpness, vessel enhancement, visibility, and image quality. In this article, we illustrate some of the vascular detail that is possible with these subsecond techniques and the potential role they can play in clinical diagnosis and patient care.