Kymogram detection and kymogram-correlated image reconstruction from subsecond spiral computed tomography scans of the heart
Kymogram detection and kymogram-correlated image reconstruction from subsecond spiral computed tomography scans of the heart
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DOI：
10.1118/1.1487861
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发表时间：
2002-07-01
期刊：
影响因子：
3.8
通讯作者：
Kalender, WA
中科院分区：
文献类型：
--
作者：
Kachelriess, M;Sennst, DA;Kalender, WA
亚秒单层、多层或锥束螺旋计算机断层扫描（SSCT、MSCT、CBCT）在改善心脏成像方面具有很大的潜力。结合新开发的相位相关心脏重建算法180degreesMCD和180degreesMCI [Med. Phys. 27,1881 - 1902(2000)]或CT厂商提供的相关算法，可以获得高质量的图像。这些算法需要有关心脏运动的信息，即通常同时记录的心电图（ECG），以使重建与心脏运动同步。没有心电图信息的数据采集（标准患者）和有损坏心电图信息的采集都不能得到充分的处理。我们开发了一种方法，直接从测量的原始数据（投影数据）中提取有关心脏运动的适当信息。所谓的心电图函数是心脏运动作为时间t的函数或作为投影角a的函数的度量。与ECG是心脏电兴奋的全局度量相反，心电图是心脏运动在z位置z（α）在投影角α的局部度量。通过一系列的信号处理步骤，可以从心电图中提取出患者的局部心率以及相位相关算法所需的同步信息。结果表明，心电图信息足以替代心电图信息。计算机模拟模拟心电图和患者测量同时获得的心电图进行了多层扫描仪提供M = 4片，以评估这些新方法。采用心电功能和心电图功能进行重建。两者在用于重建的周期性信息方面高度相关。在25例连续病例中，有21例颈内入路与ecg相关重建相当；两种方法在图像质量上只有微小的差异。1例患者心电监护仪检测到的同步信息有误；在这里，心电图构成了提供有用重建的唯一方法。12片和16片的患者研究表明我们的方法对锥束CT扫描是有用的。心电图相关重建似乎也有可能改善一般的心包区成像。(C) 2002年美国医学物理学家协会。
Subsecond single-slice, multi-slice or cone-beam spiral computed tomography (SSCT, MSCT, CBCT) offer great potential for improving heart imaging. Together with the newly developed phase-correlated cardiac reconstruction algorithms 180degreesMCD and 180degreesMCI [Med. Phys. 27, 1881- 1902 (2000)] or related algorithms provided by the CT manufacturers, high image quality can be achieved. These algorithms require information about the cardiac motion, i.e., typically the simultaneously recorded electrocardiogram (ECG), to synchronize the reconstruction with the cardiac motion. Neither data acquired without ECG information (standard patients) nor acquisitions with corrupted ECG information can be handled adequately. We developed a method to extract the appropriate information about cardiac motion directly from the measured raw data (projection data). The so-called kymogram function is a measure of the cardiac motion as a function of time t or as a function of the projection angle a. In contrast to the ECG which is a global measure of the heart's electric excitation, the kymogram is a local measure of the heart motion at the Z-position z(alpha) at projection angle alpha. The patient's local heart rate as well as the necessary synchronization information to be used with phase-correlated algorithms can be extracted from the kymogram by using a series of signal processing steps. The kymogram information is shown to be adequate to substitute the ECG information. Computer simulations with simulated ECG and patient measurements with simultaneously acquired ECG were carried out for a multislice scanner providing M = 4 slices to evaluate these new approaches. Both the ECG function and the kymogram function were used for reconstruction. Both were highly correlated regarding the periodicity information used for reconstruction. In 21 out of 25 consecutive cases the kyrnograrn approach was equivalent to the ECG-correlated reconstruction; only minor differences in image quality between both methods were observed. For one patient the synchronization information detected by the ECG monitor turned out to be wrong; here, the kymogram constituted the only approach that provided useful reconstructions. Patient studies with 12 and 16 slices indicate the usefulness of our approach for cone-beam CT scans. Kymogram-correlated reconstructions also appear to have the potential to improve imaging of pericardial lung areas in general. (C) 2002 American Association of Physicists in Medicine.