Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats.
Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats.
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DOI：
10.1109/tbme.2017.2737559
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发表时间：
2017-11
期刊：
影响因子：
--
通讯作者：
Liu Z
中科院分区：
文献类型：
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作者：
Lu KH;Cao J;Oleson ST;Powley TL;Liu Z
人类和动物胃排空和运动的评估通常需要放射性成像或侵入性测量。在这里，我们开发了一个强大的策略，图像和表征胃排空和运动的大鼠对比增强磁共振成像（MRI）和计算机辅助图像处理的基础上。训练动物自然食用钆标记的饮食凝胶，同时避免任何经口灌胃的需要。在该试验餐后，在低剂量麻醉下对动物进行7特斯拉高分辨率T1加权MRI扫描，可视化随时间变化的餐分布，与非GI组织的对比度大大增强。这种对比增强图像不仅描绘了胃解剖结构，而且还通过全自动图像处理捕获和量化了胃排空、肠充盈、胃窦收缩和肠吸收。在摄入后4小时内，胃排空了27%，主要归因于前胃而不是胃体和胃窦的排空，并且在前30分钟期间最显著。胃排空伴随前2小时的肠充盈，而随后的肠吸收可观察到肾髓质中的累积对比增强。胃窦收缩被捕获为从近端到远端胃窦传播的蠕动波。胃窦收缩的频率、速度和幅度分别为6.34±0.07次/min、0.67±0.01 mm/s和30.58± 1.03%。这些结果证明了一种基于MRI的优化策略，可以评估健康大鼠的胃排空和运动，为使用该技术了解胃肠道疾病或在大鼠模型中测试新疗法铺平了道路。
The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7-Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-GI tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully-automated image processing. Over four post-ingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 minutes. Stomach emptying was accompanied by intestinal filling for the first 2 hours, while afterwards intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34±0.07 contractions per minute, 0.67±0.01 mm/s and 30.58±1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.