P Krishnan Akshara, Joy Ajin, Paul Joseph Suresh
Indian Institute of Information Technology and Management-Kerala , Medical Image Computing and Signal Processing Laboratory, Trivandrum 695581, Kerala, India.
J Med Imaging (Bellingham). 2016 Jan;3(1):014001. doi: 10.1117/1.JMI.3.1.014001. Epub 2016 Jan 22.
In low-resolution phase contrast magnetic resonance angiography, the maximum intensity projected channel images will be blurred with consequent loss of vascular details. The channel images are enhanced using a stabilized deblurring filter, applied to each channel prior to combining the individual channel images. The stabilized deblurring is obtained by the addition of a nonlocal regularization term to the reverse heat equation, referred to as nonlocally stabilized reverse diffusion filter. Unlike reverse diffusion filter, which is highly unstable and blows up noise, nonlocal stabilization enhances intensity projected parallel images uniformly. Application to multichannel vessel enhancement is illustrated using both volunteer data and simulated multichannel angiograms. Robustness of the filter applied to volunteer datasets is shown using statistically validated improvement in flow quantification. Improved performance in terms of preserving vascular structures and phased array reconstruction in both simulated and real data is demonstrated using structureness measure and contrast ratio.
在低分辨率相衬磁共振血管造影中，最大强度投影通道图像会变得模糊，从而导致血管细节丢失。在组合各个通道图像之前，使用稳定去模糊滤波器对通道图像进行增强，该滤波器应用于每个通道。通过向反向热方程添加非局部正则化项来获得稳定去模糊，这被称为非局部稳定反向扩散滤波器。与高度不稳定且会放大噪声的反向扩散滤波器不同，非局部稳定会均匀增强强度投影平行图像。使用志愿者数据和模拟多通道血管造影说明了该方法在多通道血管增强中的应用。通过流量定量方面经统计验证的改进，展示了应用于志愿者数据集的滤波器的稳健性。使用结构度测量和对比度，在模拟数据和实际数据中均证明了在保留血管结构和相控阵重建方面的性能提升。
