For nonelectron beam systems, scan speed and image quality have reached a relative plateau of performance. Helical CT makes rapid coverage of the z axis possible, allowing scanning to occur during the optimal phase of vascular and organ enhancement. With the split breath-hold variable-mode approach, extended helical coverage across multiple anatomic regions is possible. The technique adds flexibility in choice of collimation, milliamperage, and breath-hold interval. It is easily tolerated by patients and reproducible, and the intersegment delays produce less heat loading on the x-ray tube.