Mistry Nilesh N, Pollaro James, Song Jiayu, De Lin Ming, Johnson G Allan
Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA.
Magn Reson Med. 2008 Feb;59(2):289-97. doi: 10.1002/mrm.21353.
With the development of various models of pulmonary disease, there is tremendous interest in quantitative regional assessment of pulmonary function. While ventilation imaging has been addressed to a certain extent, perfusion imaging for small animals has not kept pace. In humans and large animals perfusion can be assessed using dynamic contrast-enhanced (DCE) MRI with a single bolus injection of a gadolinium (Gd)-based contrast agent. But the method developed for the clinic cannot be translated directly to image the rodent due to the combined requirements of higher spatial and temporal resolution. This work describes a novel image acquisition technique staggered over multiple, repeatable bolus injections of contrast agent using an automated microinjector, synchronized with image acquisition to achieve dynamic first-pass contrast enhancement in the rat lung. This allows dynamic first-pass imaging that can be used to quantify pulmonary perfusion. Further improvements are made in the spatial and temporal resolution by combining the multiple injection acquisition method with Interleaved Radial Imaging and "Sliding window-keyhole" reconstruction (IRIS). The results demonstrate a simultaneous increase in spatial resolution (<200 mum) and temporal resolution (<200 ms) over previous methods, with a limited loss in signal-to-noise-ratio.
随着各种肺部疾病模型的发展，人们对肺功能的定量区域评估产生了浓厚兴趣。虽然通气成像在一定程度上已得到解决，但小动物的灌注成像却未能跟上步伐。在人类和大型动物中，可以使用动态对比增强（DCE）磁共振成像（MRI），通过单次团注钆（Gd）基对比剂来评估灌注。但由于对更高空间和时间分辨率的综合要求，为临床开发的方法不能直接用于对啮齿动物成像。这项工作描述了一种新颖的图像采集技术，该技术使用自动微量注射器在多次可重复的对比剂团注过程中交错进行，并与图像采集同步，以实现大鼠肺部的动态首过对比增强。这使得动态首过成像可用于量化肺灌注。通过将多次注射采集方法与交错径向成像和“滑动窗口 - 锁孔”重建（IRIS）相结合，进一步提高了空间和时间分辨率。结果表明，与以前的方法相比，空间分辨率（<200μm）和时间分辨率（<200ms）同时提高，而信噪比仅有有限损失。
