Bhave Nicole M, Mor-Avi Victor, Kachenoura Nadjia, Freed Benjamin H, Vannier Michael, Dill Karin, Lang Roberto M, Patel Amit R
University of Chicago Medical Center, MC5084, 5841 S. Maryland Ave, Chicago, IL 60637, USA.
University of Chicago Medical Center, MC5084, 5841 S. Maryland Ave, Chicago, IL 60637, USA.
J Cardiovasc Comput Tomogr. 2014 May-Jun;8(3):238-45. doi: 10.1016/j.jcct.2014.04.008. Epub 2014 May 2.
Iterative reconstruction (IR) in cardiac CT has been shown to improve confidence of interpretation of noninvasive coronary CT angiography (CTA).
We hypothesized that IR would also improve the quality of vasodilator stress coronary CT images acquired with low tube voltage to assess myocardial perfusion and the accuracy of the detection of perfusion abnormalities by using quantitative 3-dimensional (3D) analysis.
We studied 39 consecutive patients referred for coronary CTA (256-slice scanner; Philips), who underwent additional imaging (100 kV, prospective gating) with regadenoson (0.4 mg; Astellas). Stress images were reconstructed with different algorithms: filtered back projection (FBP) and IR (iDose; Philips). Image quality was quantified by signal-to-noise and contrast-to-noise ratios in the blood pool and the myocardium. Then, FBP and separately IR images were analyzed with custom 3D analysis software to quantitatively detect perfusion defects. Accuracy of detection was compared with perfusion abnormalities predicted by coronary stenosis >50% on coronary CTA.
Five patients with image artifacts were excluded. In the remaining 34 patients, both signal-to-noise and contrast-to-noise ratios increased with IR, indicating improvement in image quality compared with FBP. For 3D perfusion analysis, 10 patients with normal coronary arteries were used as a reference to correct for x-ray attenuation variations in normal myocardium. In the remaining 24 patients, reduced noise levels in the IR images compared with FBP resulted in tighter attenuation distribution and improved detection of perfusion abnormalities.
IR significantly improves image quality on regadenoson stress CT images acquired with low tube voltage, leading to improved 3D quantitative evaluation of myocardial perfusion.
心脏CT中的迭代重建（IR）已被证明可提高无创冠状动脉CT血管造影（CTA）解释的可信度。
我们假设IR还可提高低管电压下采集的血管扩张剂负荷冠状动脉CT图像的质量，以评估心肌灌注，并通过定量三维（3D）分析提高灌注异常检测的准确性。
我们研究了39例连续接受冠状动脉CTA检查的患者（256层扫描仪；飞利浦），这些患者接受了额外的成像检查（100 kV，前瞻性门控），使用了瑞加诺生（0.4 mg；安斯泰来）。负荷图像采用不同算法重建：滤波反投影（FBP）和IR（iDose；飞利浦）。通过血池和心肌中的信噪比和对比噪声比来量化图像质量。然后，使用定制的3D分析软件对FBP和单独的IR图像进行分析，以定量检测灌注缺损。将检测准确性与冠状动脉CTA上预测的冠状动脉狭窄>50%的灌注异常进行比较。
排除5例有图像伪影的患者。在其余34例患者中，IR重建后的信噪比和对比噪声比均增加，表明与FBP相比图像质量有所改善。对于3D灌注分析，10例冠状动脉正常的患者用作参考，以校正正常心肌中的X线衰减变化。在其余24例患者中，与FBP相比，IR图像中的噪声水平降低，导致衰减分布更紧密，并改善了灌注异常的检测。
IR显著提高了低管电压下采集的瑞加诺生负荷CT图像的质量，从而改善了心肌灌注的3D定量评估。
