Commercial mouse chow is designed to provide a complete, nutrient-rich diet, and it can contain upwards of 100 mg/kg manganese, an essential mineral. Manganese acts as a relaxation time-shortening contrast agent for both T1 and T2, and where standard chow is hydrated in the gastrointestinal tract, bright signals are produced when using T1-weighted imaging (T1WI). As a result of peristalsis, gastrointestinal hyperintensities result in temporally unstable signals, leading to image ghosting and decreased resolution from that prescribed. To avoid the problem, various methods of gastrointestinal tract modulation, including the use of intestinal cleansing with laxatives and dietary modulation, have been reported. Here, dietary modulation has been extended to the use of a biologically innocuous, long-term change of diet. In this study, we report on the use of a commercially available manganese-free chow to improve the image quality of the gastrointestinal tract. This manganese-free chow, apart from the omitted manganese which is available in tap water, is a complete diet and readily available. We investigated the time-dependent, diet-related gastrointestinal intensities on short-TR T1WI magnetic resonance imaging; monitored body mass, food and water consumption and standard blood biochemistry analysis following diet change; and determined manganese concentration in blood plasma following a five-day change to manganese-free chow. We show that the manganese-free chow presents a refinement to other gastrointestinal tract modulation, as it avoids the need for invasive procedures for gut voiding and can be provided ad libitum so that animals can be maintained with no need for prescribed diet change before imaging.

中文翻译：

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无锰饲料，一种精制的非侵入性解决方案，可减少小鼠腹部 T1 加权磁共振成像的胃肠道信号。


商业小鼠饲料旨在提供完整、营养丰富的饮食，其中锰含量高达 100 毫克/千克，锰是一种必需矿物质。锰可作为 T1 和 T2 的弛豫时间缩短造影剂，并且当标准食物在胃肠道中水合时，使用 T1 加权成像 (T1WI) 时会产生明亮的信号。由于蠕动，胃肠道高信号会导致暂时不稳定的信号，从而导致图像重影和分辨率降低。为了避免这个问题，已经报道了多种胃肠道调节方法，包括使用泻药清洁肠道和饮食调节。在这里，饮食调节已扩展到使用对生物无害的长期饮食改变。在这项研究中，我们报告了使用市售的无锰饲料来改善胃肠道的图像质量。这种无锰食物除了自来水中含有的锰之外，是一种完整的饮食，并且很容易获得。我们通过短 TR T1WI 磁共振成像研究了时间依赖性、饮食相关的胃肠道强度；监测饮食改变后的体重、食物和水消耗以及标准血液生化分析；并在更换为无锰饲料五天后测定了血浆中的锰浓度。我们表明，无锰饲料对其他胃肠道调节进行了改进，因为它避免了肠道排空的侵入性操作，并且可以随意提供，这样动物就可以在成像前不需要改变规定的饮食来维持。