“…Using gated multislice CTA, Murayama et al investigated pulsatility in AD by quantifying true lumen area changes in the axial CTA images and concluded that in AD, pulsating-type is more common if in the acute phase from onset or if the entry is not located at the distal-portion of descending-thoracic-aorta with retrograde flow in false lumen thrombosis. 23 However, the effective estimated radiation dose of 128 slice triple rule-out gated CTA for excluding AD, pulmonary embolism, and acute coronary artery syndrome was recently reported to ranged from 7.4-13.4 mSv and from 10.1-17.5 mSv for men and women, respectively, for retrospective triggered acquisitions and from 5.9 mSv and 8.2 mSv for men and women, respectively, for prospectively triggered CTAs. 24 While these doses are quite acceptable for single examinations, it may be less suitable for longitudinal studies with many repeated examinations.…”