Isotropic high-resolution in multi-slice spiral CT

Isotropic resolution in multi-slice CT with a cutoff of about 14 cm/sup -1/ has the potential of dramatically improving the quality of many CT applications. Among these are HRCT of the lungs and of the spine, orthopedics studies, and coronary arteries imaging. Obtaining this isotropic resolution with present detector scintillations can be realized by over-sampling in both the x- and the z-direction during spiral acquisition. We describe two different approaches for such a realization. One approach is the use of staggered detector array with a periodic motion of the X-ray tube source along the x-direction. Another approach is generating a periodic motion of the X-ray tube source in the x-and in the z-direction. A similar approach has been proposed to reduce windmill artifacts. For each approach, we measure the best spatial resolution offered and the corresponding suppression of image artifacts. The two approaches offer an isotropic resolution with a cutoff beyond 14 cm/sup -1/ near the iso-center. Reaching this goal using the second approach, only a minor price of windmill artifacts has to be paid. Using the first method provides artifact-free images.