Schreiner Markus M, Platzgummer Hannes, Unterhumer Sylvia, Weber Michael, Mistelbauer Gabriel, Loewe Christian, Schernthaner Ruediger E
Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
Institute of Computer Graphics and Algorithms, Technical University of Vienna, Favoritenstraße 9-11, 1040 Vienna, Austria.
Eur J Radiol. 2017 Aug;93:149-156. doi: 10.1016/j.ejrad.2017.06.002. Epub 2017 Jun 3.
To investigate radiation exposure, objective image quality, and the diagnostic accuracy of a BMI-adjusted ultra-low-dose CT angiography (CTA) protocol for the assessment of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the standard of reference.
In this prospective, IRB-approved study, 40 PAD patients (30 male, mean age 72 years) underwent CTA on a dual-source CT scanner at 80kV tube voltage. The reference amplitude for tube current modulation was personalized based on the body mass index (BMI) with 120 mAs for [BMI≤25] or 150 mAs for [25<BMI≤30]. Iterative image reconstruction was applied. The presence of significant stenoses (>70%) was assessed by two readers independently and compared to subsequent DSA. Radiation exposure was assessed with the computed tomography dose index (CTDIvol) and the dosis-length product (DLP). Objective image quality was assessed via contrast- and signal-to-noise ratio (CNR and SNR) measurements. Radiation exposure and image quality were compared between the BMI groups and between the BMI-adjusted ultra-low-dose protocol and the low-dose institutional standard protocol (ISP).
The BMI-adjusted ultra-low-dose protocol reached high diagnostic accuracy values of 94% for Reader 1 and 93% for Reader 2. Moreover, in comparison to the ISP, it showed significantly (p<0.001) lower CTDIvol (1.97±0.55mGy vs. 4.18±0.62 mGy) and DLP (256±81mGy x cm vs. 544±83mGy x cm) but similar image quality (p=0.37 for CNR). Furthermore, image quality was similar between BMI groups (p=0.86 for CNR).
A CT protocol that incorporates low kV settings with a personalized (BMI-adjusted) reference amplitude for tube current modulation and iterative reconstruction enables very low radiation exposure CTA, while maintaining good image quality and high diagnostic accuracy in the assessment of PAD.
以数字减影血管造影（DSA）作为参考标准，研究体重指数（BMI）调整后的超低剂量CT血管造影（CTA）方案在评估外周动脉疾病（PAD）时的辐射暴露、客观图像质量及诊断准确性。
在这项经机构审查委员会（IRB）批准的前瞻性研究中，40例PAD患者（30例男性，平均年龄72岁）在双源CT扫描仪上于80kV管电压下接受CTA检查。管电流调制的参考幅度根据体重指数（BMI）进行个性化设置，BMI≤25时为120mAs，25<BMI≤30时为150mAs。应用迭代图像重建技术。由两名阅片者独立评估显著狭窄（>70%）的存在情况，并与随后的DSA结果进行比较。通过计算机断层扫描剂量指数（CTDIvol）和剂量长度乘积（DLP）评估辐射暴露。通过对比度和信噪比（CNR和SNR）测量评估客观图像质量。比较BMI组之间以及BMI调整后的超低剂量方案与低剂量机构标准方案（ISP）之间的辐射暴露和图像质量。
BMI调整后的超低剂量方案，阅片者1的诊断准确率高达94%，阅片者2为93%。此外，与ISP相比，其CTDIvol（1.97±0.55mGy对4.18±0.62mGy）和DLP（256±81mGy·cm对544±83mGy·cm）显著更低（p<0.001），但图像质量相似（CNR的p=0.37）。此外，BMI组之间的图像质量相似（CNR的p=0.86）。
一种结合低kV设置、管电流调制的个性化（BMI调整）参考幅度以及迭代重建的CT方案，能够实现极低辐射暴露的CTA，同时在评估PAD时保持良好的图像质量和高诊断准确性。
