步进式双源CT：低辐射剂量的无创冠状动脉造影

Dual-source CT in step-and-shoot mode: noninvasive coronary angiography with low radiation dose.

作者信息

Stolzmann Paul, Leschka Sebastian, Scheffel Hans, Krauss Tobias, Desbiolles Lotus, Plass André, Genoni Michele, Flohr Thomas G, Wildermuth Simon, Marincek Borut, Alkadhi Hatem

机构信息

Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.

出版信息

Radiology. 2008 Oct;249(1):71-80. doi: 10.1148/radiol.2483072032.

DOI:10.1148/radiol.2483072032

PMID:18796669

Abstract

PURPOSE

To prospectively investigate computed tomographic (CT) image quality parameters by using different protocols and to calculate radiation dose estimates for noninvasive coronary angiography performed with dual-source CT in the step-and-shoot (SAS) mode.

MATERIALS AND METHODS

This study was local ethics board approved; written informed consent was obtained from all patients. In the preliminary portion of the study, 40 patients underwent CT coronary angiography in the SAS mode: at 100 kV (protocol A) in 22 patients with a body mass index (BMI) of less than 25 kg/m(2) and at 120 kV (protocol B) in 18 patients with a BMI of 25-30 kg/m(2). Both protocols involved use of an attenuation-based tube current and 1 mL of contrast material per kilogram of body weight. The final portion of the study involved 50 additional patients: 21 patients with a BMI of 25-30 kg/cm(2) assigned to protocol B and 29 patients with a BMI of less than 25 kg/cm(2) assigned to protocol C, which was performed with 100 kV, an attenuation-based tube current, and a reduced contrast material dose of 0.8 mL/kg. Image quality was independently assessed. Attenuation in the aorta and coronary arteries and image noise were measured. Radiation dose was estimated.

RESULTS

Mean image noise was similar with protocols A and B. Mean attenuation in the aorta and coronary arteries with protocol A (444 HU) was significantly (P < .001) higher than that with protocol B (358 HU). The reduced contrast material dose in protocol C yielded attenuation similar to that with protocol B. Diagnostic image quality was achieved with all protocols in 1237 (97.9%) of 1264 coronary segments. No significant differences in image quality between the 100- and 120-kV protocols were found. Mean heart rate had a significant effect on motion artifacts (area under receiver operating characteristic curve [AUC] = 0.818; 95% confidence interval [CI]: 0.723, 0.892; P < .001), whereas heart rate variability had a significant effect on stair-step artifacts (AUC = 0.79; 95% CI: 0.687, 0.865; P < .001). The mean estimated effective dose was 1.2 mSv +/- 0.2 for protocols A and C and 2.6 mSv +/- 0.5 for protocol B.

CONCLUSION

Dual-source SAS-mode CT coronary angiography yielded diagnostic image quality for 97.9% of coronary segments at a low radiation dose.

摘要

目的

前瞻性研究使用不同方案时的计算机断层扫描（CT）图像质量参数，并计算在步进-扫描（SAS）模式下采用双源CT进行无创冠状动脉造影时的辐射剂量估计值。

材料与方法

本研究经当地伦理委员会批准；所有患者均签署了书面知情同意书。在研究的初步阶段，40例患者以SAS模式接受CT冠状动脉造影：22例体重指数（BMI）小于25kg/m²的患者采用100kV（方案A），18例BMI为25 - 30kg/m²的患者采用120kV（方案B）。两种方案均采用基于衰减的管电流，每千克体重使用1mL对比剂。研究的最后阶段纳入另外50例患者：21例BMI为25 - 30kg/cm²的患者分配至方案B，29例BMI小于25kg/cm²的患者分配至方案C，方案C采用100kV、基于衰减的管电流，对比剂剂量减少至0.8mL/kg。图像质量由独立人员进行评估。测量主动脉和冠状动脉的衰减以及图像噪声。估计辐射剂量。

结果

方案A和方案B的平均图像噪声相似。方案A时主动脉和冠状动脉的平均衰减（444HU）显著高于方案B（358HU）（P <.001）。方案C中对比剂剂量减少后，衰减与方案B相似。1264个冠状动脉节段中的1237个（97.9%）采用所有方案均获得了诊断性图像质量。100kV和120kV方案之间的图像质量无显著差异。平均心率对运动伪影有显著影响（受试者操作特征曲线下面积[AUC]=0.818；95%置信区间[CI]：0.723，0.892；P <.001），而心率变异性对阶梯状伪影有显著影响（AUC = 0.79；95%CI：0.687，0.865；P <.001）。方案A和C的平均估计有效剂量为1.2mSv±0.2，方案B为2.6mSv±0.5。