Ulrich Anne, Burg Matthias C, Raupach Rainer, Bunck Alexander, Schuelke Christoph, Maintz David, Heindel Walter, Seifarth Harald
Department of Clinical Radiology, University of Muenster, Münster, Germany.
Siemens Medical Solutions, Computed Tomography CTE PA, Forchheim, Germany.
Acta Radiol. 2015 Jan;56(1):42-50. doi: 10.1177/0284185113517229. Epub 2014 Jan 7.
Assesment of the coronary arteries after stent placement using coronary computed tomography angiography (CCTA) currently requires reconstruction of images with soft kernels for the assessment of atherosclerotic plaques and dedicated edge enhancing kernels for the evaluation of the stent lumen.
To evaluate a two-dimensional filter tool that provides instant postprocessing of images reconstructed with soft kernels into edge-enhanced images and vice versa and thus may eliminate the need for two separate reconstrcutions for the assessment of coronary artery stents using CCTA.
Twenty stents with a diameter of 3.0 mm placed in a vascular phantom were scanned with a dual-source CT using standard parameters. Images were reconstructed with a soft B30f and an edge-enhancing B46f kernel and postprocessed with the corresponding filter algorithm (F30 for B30f images; F46 for B46f images). The resulting four data-sets were evaluated for lumen visibility, intraluminal attenuation, and image noise by two independent readers. Results were validated in vivo against invasive coronary angiography in data-sets from patients with coronary artery stents.
Average intraluminal attenuation was 552.6 HU, 527.3 HU, 207.9 HU, and 267.5 HU for B30f, F30, B46f, and F46 images, respectively (P < 0.0001). Average image noise was 11.3, 10.6, 19.2, and 15.0 HU, respectively (P < 0.0001). The visible stent diameter was significantly higher in the B46f (59.6%) and F46 images (54%) compared to the B30f (48.3%) and F30 (51.5%) images (P < 0.0001). In the patient study, lumen assessability was significantly better in B46f images than in F46 images. Sensitivity for stenosis detection was best in the original B46f images with a sensitivity of 67% and a specificity of 94%.
The postprocessing filter reduces image noise, however currently it does not offer an alternative to image reconstruction using the edge-enhancing kernels for the evaluation of the stent lumen.
目前，使用冠状动脉计算机断层扫描血管造影（CCTA）评估支架置入后的冠状动脉需要重建具有软组织内核的图像以评估动脉粥样硬化斑块，并使用专门的边缘增强内核来评估支架管腔。
评估一种二维滤波工具，该工具可将使用软组织内核重建的图像即时后处理为边缘增强图像，反之亦然，从而可能无需使用CCTA对冠状动脉支架进行评估时进行两次单独的重建。
使用双源CT以标准参数扫描放置在血管模型中的20个直径为3.0毫米的支架。图像用软组织B30f内核和边缘增强B46f内核重建，并用相应的滤波算法进行后处理（B30f图像用F30；B46f图像用F46）。由两名独立的阅片者对所得的四个数据集进行管腔可见性、管腔内衰减和图像噪声评估。结果在体内与冠状动脉支架患者数据集中的有创冠状动脉造影结果进行了验证。
B30f、F30、B46f和F46图像的平均管腔内衰减分别为552.6 HU、527.3 HU、207.9 HU和267.5 HU（P < 0.0001）。平均图像噪声分别为11.3、10.6、19.2和15.0 HU（P < 0.0001）。与B30f（48.3%）和F30（51.5%）图像相比，B46f（59.6%）和F46图像（54%）中可见的支架直径明显更高（P < 0.0001）。在患者研究中，B46f图像中的管腔可评估性明显优于F46图像。狭窄检测的敏感性在原始B46f图像中最佳，敏感性为67%，特异性为94%。
后处理滤波器可降低图像噪声，但目前它不能替代使用边缘增强内核进行图像重建来评估支架管腔。
