CT angiography: State of the art and future developments

The development of spiral acquisition techniques and the growing technology applied to both CT equipment and post-processing systems, have shown CT angiography (CTA), to be a complementary method to conventional Angiography, magnetic resonance angiography (MRA) or ultrasound, for the morphologic evaluation of vascular structures. Through the administration via intravenous injection of a contrast media and by means of a fast acquisition of the Region Of Interest, we obtain the primary information to be processed and displayed according to various imaging techniques: Axial images, MultiPlanar Reformatting (MPR), volume rendering (3D) or shaded surface display (SSD), Maximum Intensity Projection (MIP), Endoscopic-CT etc. All of these processing methods, perform as a first step of the whole process, longitudinal interpolations by the data of the images. Even though few methods to improve the quality of the images exist, among these the use of overlapping sections, the precision requires of the post-processing procedures to accomplish the medical requirements for diagnosis, is affected by a common factor which is the absolute anisotropicity of the acquisition voxel (dimension along the ''Z'' axis different and bigger than those in the transverse plane). This represents the goal-parameter on which the various competitors will have to focus their efforts in order to obtain results with an improved diagnostic validity. At present, the systems with dual-slice acquisition, represent the first step of what will be the acquisition technology of the future: ''multi-slice''. At the same time, the technologic growth of post-processing workstations, will permit the development of new clinical applications combined with Spiral-CT acquisition which will broaden the horizons of modern medicine.