Maruyama Takao, Takada Masanori, Hasuike Toshiaki, Yoshikawa Atsushi, Namimatsu Eiji, Yoshizumi Tohru
Department of Cardiology, Kawasaki Hospital, Kobe, Japan.
J Am Coll Cardiol. 2008 Oct 28;52(18):1450-5. doi: 10.1016/j.jacc.2008.07.048.
The aim of this study was to evaluate radiation dose and coronary assessability of a prospective electrocardiogram (ECG)-gated scan by 64-slice multidetector (row) computed tomography (MDCT)-coronary angiography (CA) compared with a retrospective ECG-gated helical scan.
The 64-slice MDCT-CA has been widely used; however, a high radiation dose by 64-slice MDCT-CA has been reported. Prospective ECG-gated scan using "step-and-shoot" protocol can reduce radiation exposure effectively.
MDCT-CA was performed in 229 consecutive patients. Fifty-six patients were excluded because of higher heart rates of >65 beats/min; of patients with heart rates <or=65 beats/min, 97 were analyzed by helical scan with tube current modulation and 76 were analyzed by prospective gating. Coronary assessability and diagnostic accuracy were investigated in comparison with selective CA as the gold standard. Radiation doses were evaluated in both protocols.
Coronary assessability of helical scan was 95.5% (1,303 of 1,364 segments), while that of prospective gating was 96.6% (1,053 of 1,089 segments), showing similar coronary assessability (p = 0.14). Sensitivity and specificity for coronary obstructive and occlusive lesions in the assessable segments were 97.0% (162 of 167) and 97.6% (1,109 of 1,136) by helical scan, while those of prospective gating were 96.4% (81 of 84, p = 0.84) and 98.5% (955 of 969, p = 0.12), respectively. Effective doses of helical scan and prospective gating were 21.1 +/- 6.7 mSv and 4.3 +/- 1.3 mSv, respectively (p < 0.0001), showing that prospective gating decreased radiation dose by 79% compared with that of helical scan.
MDCT-CA by prospective gating showed equivalent coronary assessability and diagnostic accuracy with decreased radiation dose in comparison with a retrospective ECG-gated helical scan with tube current modulation.
本研究旨在评估与回顾性心电图(ECG)门控螺旋扫描相比,64层多排螺旋计算机断层扫描(MDCT)冠状动脉造影(CA)进行前瞻性ECG门控扫描时的辐射剂量和冠状动脉可评估性。
64层MDCT-CA已被广泛应用;然而,有报道称64层MDCT-CA的辐射剂量较高。采用“步进-采集”协议的前瞻性ECG门控扫描可有效降低辐射暴露。
对229例连续患者进行MDCT-CA检查。56例患者因心率>65次/分钟被排除;在心率≤65次/分钟的患者中,97例采用管电流调制的螺旋扫描进行分析,76例采用前瞻性门控进行分析。与作为金标准的选择性CA相比,研究冠状动脉可评估性和诊断准确性。对两种方案的辐射剂量进行评估。
螺旋扫描的冠状动脉可评估性为95.5%(1364段中的1303段),而前瞻性门控为96.6%(1089段中的1053段),显示出相似的冠状动脉可评估性(p = 0.14)。螺旋扫描对可评估段冠状动脉阻塞性和闭塞性病变的敏感性和特异性分别为97.0%(167例中的162例)和97.6%(1136例中的1109例),而前瞻性门控的敏感性和特异性分别为96.4%(84例中的81例,p = 0.84)和98.5%(969例中的955例,p = 0.12)。螺旋扫描和前瞻性门控的有效剂量分别为21.1±6.7 mSv和4.3±1.3 mSv(p < 0.0001),表明前瞻性门控与螺旋扫描相比,辐射剂量降低了79%。
与采用管电流调制的回顾性ECG门控螺旋扫描相比,前瞻性门控的MDCT-CA显示出相当的冠状动脉可评估性和诊断准确性,且辐射剂量降低。