Sauter Andreas, Koehler Thomas, Brendel Bernhard, Aichele Juliane, Neumann Jan, Noël Peter B, Rummeny Ernst J, Muenzel Daniela
1 Department of diagnostic and interventional Radiology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.
2 Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany.
Acta Radiol. 2019 Apr;60(4):478-487. doi: 10.1177/0284185118784976. Epub 2018 Jun 22.
Computed tomography pulmonary angiography (CTPA) is the standard imaging modality for detection or rule out of pulmonary embolism (PE); however, radiation exposure is a serious concern. With iterative reconstruction algorithms a distinct dose reduction could be achievable.
To evaluate a next generation iterative reconstruction algorithm for detection or rule-out of PE in simulated low-dose CTPA.
Low-dose CT datasets with 50%, 25%, and 12.5% of the original tube current were simulated based on CTPA examinations of 92 patients with suspected PE. All datasets were reconstructed with two reconstruction algorithms: standard filtered back-projection (FBP) and iterative model reconstruction (IMR). In total, 736 CTPA datasets were evaluated by three blinded radiologists regarding image quality, diagnostic confidence, and detectability of PE. Furthermore, contrast-to-noise ratio (CNR) was calculated.
Images reconstructed with IMR showed better detectability of PE than images reconstructed with FBP, especially at lower dose levels. With IMR, sensitivity was over 95% for central and segmental PE down to a dose level of 25%. Significantly higher subjective image quality was shown at lower dose levels (25% and 12.5%) for IMR images whereas it was higher for FBP images at higher dose levels. FBP was rated as showing less artificial image appearance. CNR was significantly higher with IMR at all dose levels.
By using IMR, a dose reduction of up to 50% while maintaining satisfactory image quality seems feasible in standard clinical situations, resulting in a mean effective dose of 1.38 mSv for CTPA.
计算机断层扫描肺动脉造影（CTPA）是检测或排除肺栓塞（PE）的标准成像方式；然而，辐射暴露是一个严重问题。使用迭代重建算法可实现明显的剂量降低。
评估一种用于在模拟低剂量CTPA中检测或排除PE的新一代迭代重建算法。
基于对92例疑似PE患者的CTPA检查，模拟了原始管电流50%、25%和12.5%的低剂量CT数据集。所有数据集均采用两种重建算法进行重建：标准滤波反投影（FBP）和迭代模型重建（IMR）。三位盲法放射科医生对总共736个CTPA数据集的图像质量、诊断信心和PE的可检测性进行了评估。此外，还计算了对比噪声比（CNR）。
与FBP重建的图像相比，IMR重建的图像对PE的可检测性更好，尤其是在较低剂量水平时。使用IMR，对于中央型和节段型PE，在剂量水平低至25%时，敏感性超过95%。在较低剂量水平（25%和12.5%），IMR图像的主观图像质量明显更高，而在较高剂量水平，FBP图像的主观图像质量更高。FBP被评为显示的人工图像外观较少。在所有剂量水平下，IMR的CNR均显著更高。
在标准临床情况下，使用IMR在保持令人满意的图像质量的同时将剂量降低高达50%似乎是可行的，CTPA的平均有效剂量为1.38 mSv。
