Characterising IBS subtypes and their response to Stress using MRI

肠易激综合征(IBS)是一种非常常见的疾病，会导致反复的腹痛和反复无常的排便习惯。虽然不是致命的，但它会显着降低患者的生活质量。IBS患者报告了一系列令人困惑的排便习惯障碍，包括腹泻和便秘，有时发生在同一患者身上。患者报告的症状是主观的，如果没有可靠的方法来测量肠功能，其意义是不确定的。超过一半的IBS患者异常焦虑，三分之二的人认为他们的症状与压力有关，这可能解释了排便习惯的日复一日的变化。然而，很难客观地确定应激对任何个体患者的影响。我们最近开发并验证了一种新的、非侵入性的磁共振成像(MRI)技术来成像小肠和结肠功能。我们认为，这可能是一种方便的测试，比目前使用的许多测试成本更低，可以客观地评估IBS患者并量化他们对压力的反应。我们认为，压力通过释放一种名为CRF的化学物质来作用于胃肠道系统，这种化学物质通过神经系统和肠道中称为肥大细胞的特殊细胞发挥作用。这会刺激收缩并加速肠道运动。我们最近发现，MRI可以检测CRF对小肠的影响，在注射后30分钟内，小肠的水分减少了三分之一。此前的研究表明，CRF还会刺激结肠收缩。我们的目标是开发经济有效地分析结肠图像的新方法，以补充我们研究小肠水分含量和肠道运动速度的方法。我们将描述不同亚型IBS患者的小结肠水分含量和转移率，我们还将评估结肠粘膜中的肥大细胞。然后，我们将通过检查MRI参数、肥大细胞激活与应激心理指标之间的相关性来检验我们的假设，即IBS患者的肠道及其肥大细胞对应激更敏感。我们的研究将有助于更好地了解IBS患者的肠道功能异常和应激的影响。它们还可能提供新的方法来预测个体对不同治疗的反应。

Irritable Bowel Syndrome (IBS) is an extremely common condition which causes recurrent abdominal pain and erratic bowel habits. Although not fatal it can markedly reduce the sufferer‘s quality of life. IBS sufferers report a confusing range of disturbances of bowel habit including both diarrhoea and constipation, sometimes in the same patient. Patients reported symptoms are subjective and their significance is uncertain without a reliable way of measuring bowel function. More than half the IBS patients are abnormally anxious and two thirds believe their symptoms are stress related, which may explain the day to day variability in bowel habit. However it is difficult to objectively determine the effect of stress in any individual patient. We have recently developed and validated a new, non-invasive, Magnetic Resonance Imaging (MRI) technique to image small bowel and colon function. We believe that this could be a convenient test, costing less than many currently used tests, to objectively assess IBS patients and quantify their responsiveness to stress. We believe that stress acts on the gastrointestinal system by releasing a chemical, called CRF which acts via the nervous system and special cells in the gut called mast cells. This stimulates contractions and accelerate movements through the bowel. We have recently shown that MRI can detect the effect of CRF on the small bowel whose water content is reduced by 1/3rd within 30 minutes of injection. Previous studies show that CRF also stimulates colonic contractions. We aim to develop new methods of economically and effectively analysing colon images to compliment our method of studying small bowel water content and rates of movement through the gut. We will characterise the small and colonic water content and transit rates in various subtypes of IBS patients in whom we will also assess mast cells in the colonic mucosa. We will then test our hypothesis that the bowel and its mast cells in IBS patients are more sensitive to the stress by examining the correlation between MRI parameters, mast cell activation and psychological markers of stress. Our studies will lead to a better understanding of abnormalities of gut function and the effect of stress in IBS patients. They may also provide novel ways of predicting the response of individuals to different treatments.