Algorithms and Clinical Application of Multislice Cardiac CT

Cardiac imaging is a demanding application for any non-invasive imaging modality. On the one hand, high temporal resolution is needed to virtually freeze the cardiac motion and to avoid motion artifacts in the images. On the other hand, sufficient spatial resolution - at best sub-millimeter - is required to adequately visualize small and complex anatomical structures like the coronary arteries. The complete heart volume has to be examined within one short breath-hold time to avoid breathing artifacts and to limit the amount of contrast agent if necessary. In 1984, Electron Beam CT (EBCT) has been introduced as a non-invasive imaging modality for the diagnosis of coronary artery disease [1-4]. The temporal resolution of 100 ms allows for motion-free imaging of the cardiac anatomy in the diastolic heart phase even at higher heart rates. Due to the restriction to non-spiral scanning in ECG-synchronized cardiac investigations, a single breath-hold scan of the heart requires slice widths not smaller than 3 mm. The resulting transverse resolution is limited and not adequate for 3D visualization of the coronary arteries. With the advent of sub-second rotation combined with prospective ECG triggering or retrospective ECG gating, mechanical single-slice spiral-CT systems with superior general image quality have been used for cardiac imaging [4,5]. Since 1999,4-slice CT systems, which have the potential to overcome the drawbacks of single-slice cardiac CT-scanning