64DAS-MDCTを用いた下肢血管angiographyにおける撮影方法の考案：twopointROImethod

摘要

近年multidetectorcomputedtomography（以下MDCT）の進歩はめざましく，時間分解能，空間分解能の向上はもとより，detectorの多列化により広範囲を短時間で撮影することが可能となった．それに伴い血管撮影装置の使用が主流であったangiographyは，calcificationやatheroma等血管性状の描出能，侵襲度，造影手技の簡便性，コスト面においても優れているという理由からMDCTを用いたangiographyに取って代わりつつある．%In CT angiography of the lower extremities, we have developed a 2-point ROI detection bolus-tracking method (2ROI-BTM) to provide the optimal contrast medium concentration and reduce contrast medium. The time to reach the ankle from the abdominal aorta was 22.5 s (95% central range, 14.6-40.1 s). The mean scan time was 13.6 s (range, 11.5-15.0 s). In the 2ROI-BTM (n=78), the mean CT number was 516 HU in the aorta, 427 HU in the popliteal artery, and 323 HU in the tibial artery. Compared with the TIM (n=66), the CT number was low in only 3% or less of cases, and the usual contrast medium dose of 20 ml for test injection could be reduced. With the 2ROI-BTM, the optimal scan timing can be determined more easily than with the TIM, allowing the contrast medium dose to be reduced by 26% and providing contrast enhancement with superior reproducibility of morphological characteristics for the generation of 3D images.