使用心脏的长轴和短轴MRI图像组合改进心脏整体功能的评估。
Improved estimation of the cardiac global function using combined long and short axis MRI images of the heart.
作者信息
El-Rewaidy Hossam, Fahmy Ahmed S
机构信息
Systems and Biomedical Engineering Department, Cairo University, Cairo, 12613, Egypt.
Center for Informatics Science, Nile University, Cairo, 12588, Egypt.
出版信息
Biomed Eng Online. 2016 Apr 27;15:45. doi: 10.1186/s12938-016-0156-3.
BACKGROUND
Estimating the left ventricular (LV) volumes at the different cardiac phases is necessary for evaluating the cardiac global function. In cardiac magnetic resonance imaging, accurate estimation of the LV volumes requires the processing a relatively large number of parallel short-axis cross-sectional images of the LV (typically from 9 to 12). Nevertheless, it is inevitable sometimes to estimate the volume from a small number of cross-sectional images, which can lead to a significant reduction of the volume estimation accuracy. This usually encountered when a number of cross-sectional images are excluded from analysis due to patient motion artifacts. In some other cases, the number of image acquisitions is reduced to accommodate patients who cannot withstand long scan times or multiple breath-holds. Therefore, it is required to improve the accuracy of estimating the LV volume from a reduced number of acquisitions.
METHODS
In this work, we propose a method for accurately estimating the LV volume from a small number of images. The method combines short-axis (SAX) and long axis (LAX) cross sectional views of the heart to accurately estimate the LV volumes. In this method, the LV is divided into a set of consecutive chunks and a simple geometric model is then used to calculate the volume of each chunk. Validation and performance evaluation of the proposed method is achieved using real MRI datasets (25 patients) in addition to CT-based phantoms of human hearts.
RESULTS
The results show a better performance of the proposed method relative to the other available techniques. It is shown that, at the same number of cross-sectional images, the volume calculation error is significantly lower than that of current methods. In addition, the experiments show that the results of the proposed model are reproducible despite variable orientations of the imaged cross-sections.
CONCLUSION
A new method for calculating the LV volume from a set of SAX and LAX MR images has been developed. The proposed method is based on fusing the SAX and LAX segmented contours to accurately estimate the LV volume from a small number of images. The method was tested using simulated and real MRI datasets and the results showed improved accuracy of estimating the LV volume from small number of images.
背景
评估心脏整体功能时，估算不同心动周期的左心室（LV）容积很有必要。在心脏磁共振成像中，准确估算LV容积需要处理相对大量的LV平行短轴横截面图像（通常为9至12幅）。然而，有时不可避免地要从少量横截面图像估算容积，这可能导致容积估算准确性大幅降低。当由于患者运动伪影而将一些横截面图像排除在分析之外时，通常会遇到这种情况。在其他一些情况下，为了适应无法耐受长时间扫描或多次屏气的患者，会减少图像采集数量。因此，需要提高从减少的采集数量中估算LV容积的准确性。
方法
在这项研究中，我们提出了一种从少量图像准确估算LV容积的方法。该方法结合心脏的短轴（SAX）和长轴（LAX）横截面视图来准确估算LV容积。在这种方法中，LV被划分为一组连续的块，然后使用简单的几何模型计算每个块的容积。除了基于CT的人体心脏模型外，还使用真实的MRI数据集（25名患者）对所提出的方法进行验证和性能评估。
结果
结果表明，相对于其他现有技术，所提出的方法性能更好。结果显示，在横截面图像数量相同的情况下，容积计算误差明显低于当前方法。此外，实验表明，尽管成像横截面的方向不同，所提出模型的结果仍具有可重复性。
结论
已开发出一种从一组SAX和LAX MR图像计算LV容积的新方法。所提出的方法基于融合SAX和LAX分割轮廓，以从少量图像中准确估算LV容积。该方法使用模拟和真实的MRI数据集进行了测试，结果表明从少量图像估算LV容积的准确性有所提高。
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