Developments in multidetector computed tomography (MDCT) are largely driven by the goal of high quality, reproducible, and accurate coronary CT angiography that is simple to perform and simple to interpret. Until recently, 64-slice CT was considered state-of-the-art; the 64 slices per gantry rotation were achieved with either 64-detector rows, or 32-detector rows and a strategy to double the slice number by alternating the focal spot of the X-ray source. These ‘‘64-generation’’ scanners offered considerable advantages over earlier technology such as superior spatial resolution and volume coverage. Temporal resolution was dramatically improved with the introduction of dual source CT. All four CT vendors have released new products for cardiac CT since November 2007 at the annual meeting of the Radiological Society of North America (RSNA). Many developments have focused on lowering the patient radiation dose and applications for lower dose imaging. Some of these features were available for ‘‘64-generation’’ scanners, although doses using these technologies varied [1]. The group of new technologies can be called the ‘‘post-64’’ era [2] of coronary CT angiography (CTA). This collection of advances is difficult to name more descriptively because, unlike the evolution from 4 to 64 detector row coronary CTA, current CT releases are far from uniform, reflecting different approaches to image acquisition in the post-64 era. No single CT scanner offers the full portfolio of newest features. However, each offers coronary CTA with radiation doses reported (or marketed, for those new technologies that do not have peer-review publications to date) as comparable to, or lower than, conventional coronary angiography. This Special Edition compiles peer-review low dose imaging articles from authors who use all major CT platforms. Below is a brief summary of new cardiac CT technologies as of February 2009. The descriptions are far from complete, but additional detail will be found in the pages to follow, including an overview of dose reduction techniques from Dr. Halliburton. Most cardiovascular imagers primarily use only one CT platform. This potentially introduces bias. Under normal circumstances, such bias could be considered detrimental. However, in this Special Issue the editorial staff has purposely solicited input from users of each vendor. The most recent strategy (US approval in October 2008) for cardiac CT imaging features a scanner with two 4 cm detectors (dual source), each with 64 detector rows (128 slices each with an alternating focal spot) and a 285 ms gantry rotation time (Somatom Definition Flash, Siemens Medical Systems, F. J. Rybicki (&) Applied Imaging Science Laboratory, Department of Radiology, Noninvasive Cardiovascular Imaging Program, Brigham and Women’s Hospital & Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA e-mail: frybicki@partners.org