低管電流撮影•フル再構成による前向き心電図同期320列面検出器CT冠動脈血管造影

摘要

Background: It is possible to obtain equivalent image quality and a lower radiation dose using low tube current scanning with full reconstruction as compared to usual tube current scanning with half reconstruction in a 320-row area detector computed tomography (ADCT) angiography. Method: Of 589 patient underwent coronary CT angiography (CCTA), 11 patients with (RR-PQ)≥1069 ms were enrolled. In those patients, low tube current (50％ mA) scanning with full or half reconstruction were performed. As a control, 11 patients with matched pairs of tube voltage, BMI and heart rate who underwent usual scanning with half reconstruction (100％ mA with half reconstruction) were selected. Standard deviation of the CT value (SD) was measured in aorta (Ao), left atrium (LA) and left ventricle (LV), and extended dose-length products (DLP.e) were calculated. Result: Significant motion artifact was not observed in any patients. SD of 50％ mA with half reconstruction, 50％ mA with full reconstruction, and 100％ mA with half reconstruction were 28.1±2.6, 20.3±1.9, 20.7±2.5 HU in Ao, 34.4±4.4, 24.9±2.8, 24.9±3.1 HU in LA, and 29.7±2.3, 21.7±1.9, 22.1±2.3 HU in LV, respectively. There were not significant differences between 50％ mA with full reconstruction and 100％ mA with half reconstruction, but there were significant differences between 50％ mA with half reconstruction and 50％ mA with full reconstruction in all sites. The DLP.e of 50％ mA scanning (74.1±21.8 mGy•cm) was significantly lower than 100％ mA scanning (161.9±28.9 mGy•cm). Conclusion: CCTA with lower radiation dose and equivalent image quality can be obtained by ADCT using 50％ mA scanning with full reconstruction in patients with (RR-PQ)≥1069 ms.%冠動脈computed tomography血管适影(coronary CT angiography: CCTA)はmultidetector row CT(MDCT)の多列化とそれに伴う技術進歩によって広く普及した. 現在最も列数の多い320列area detector computed tomography(ADCT)(Aquilion ONE™: 東芝メディカルシステムズ社製)は160mm(0.5mm×320列)の検出器幅をもち，寝台移動なしに心臓全体の画像を得ることが可能である.