Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.
Eur J Radiol. 2012 Dec;81(12):3691-6. doi: 10.1016/j.ejrad.2010.11.021. Epub 2010 Dec 15.
To investigate the dose reduction potential of low kV triple-rule-out dual-source CT angiography (TRO-CTA) in non-obese (BMI ≤ 25 kg/m(2)) patients with acute chest pain.
Sixty consecutive patients were randomly assigned to two different retrospectively ECG-gated TRO-CTA protocols in this prospective trial: Thirty patients were examined with a 120-kV standard protocol (320 reference mAs with automatic tube current modulation, automatically adapted pitch and ECG-pulsing) and served as the control group (group 1), an otherwise identical 100 kV protocol was used in the other thirty patients (group 2) for a radiation dose reduction. Subjective image quality was assessed on a 5 point scale (1: excellent, 5: non-diagnostic) by two blinded observers. Quantitative image analysis assessed vascular attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in different vascular segments. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSvmGy(-1)cm(-1).
There was no significant difference of age, BMI, heart rate, pitch or scan length between both patient groups. Subjective image quality was rated similar in both groups (group 1: 1.2 ± 0.4, group 2: average score=1.3 ± 0.5). Vessel attenuation was significantly higher in group 2 than in group 1 (ascending aorta: 456 ± 83 HU vs. 370 ± 78 HU, p<0.001; pulmonary artery: 468 ± 118 HU vs. 411 ± 91 HU, p=0.03; left coronary artery: 437 ± 110 HU vs. 348 ± 89 HU, p<0.001), however, there was no significant difference in SNR (13.2 ± 7.6 vs. 14.5 ± 7.5, p=0.49) or CNR (13.8 ± 6.6 vs. 15.9 ± 7.7, p=0.25). The effective radiation dose of the 100 kV protocol was significantly lower (9.6 ± 3.2 mSv vs. 18.1 ± 9.4 mSv, p<0.0001).
TRO-CTA with 100 kV is feasible in non-obese patients and results in diagnostic image quality and significantly reduced radiation dose.
探讨低千伏三联征双源 CT 血管造影（TRO-CTA）在非肥胖（BMI≤25kg/m2）急性胸痛患者中降低剂量的潜力。
本前瞻性试验中，连续 60 例患者被随机分配到两种不同的回顾性 ECG 门控 TRO-CTA 方案：30 例患者采用 120kV 标准方案（320 参考 mAs 自动管电流调制，自动适应螺距和 ECG 脉冲）作为对照组（组 1），另外 30 例患者采用相同的 100kV 方案（组 2）进行辐射剂量降低。两名盲法观察者采用 5 分制评估主观图像质量（1：极好，5：无法诊断）。定量图像分析评估不同血管节段的血管衰减、信噪比（SNR）和对比噪声比（CNR）。有效剂量通过剂量长度乘积（DLP）乘以转换系数 0.017 mSvmGy-1cm-1计算得出。
两组患者的年龄、BMI、心率、螺距或扫描长度无显著差异。两组的主观图像质量评分相似（组 1：1.2±0.4，组 2：平均评分=1.3±0.5）。与组 1 相比，组 2 的血管衰减明显更高（升主动脉：456±83HU 比 370±78HU，p<0.001；肺动脉：468±118HU 比 411±91HU，p=0.03；左冠状动脉：437±110HU 比 348±89HU，p<0.001），但 SNR（13.2±7.6 比 14.5±7.5，p=0.49）或 CNR（13.8±6.6 比 15.9±7.7，p=0.25）无显著差异。100kV 方案的有效辐射剂量明显降低（9.6±3.2mSv 比 18.1±9.4mSv，p<0.0001）。
非肥胖患者行 100kV TRO-CTA 是可行的，可获得诊断图像质量，并显著降低辐射剂量。
