Siddiki Hassan, Fidler Jeff
Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Eur J Radiol. 2009 Mar;69(3):409-17. doi: 10.1016/j.ejrad.2008.11.013. Epub 2008 Dec 31.
MR and CT techniques optimized for small bowel imaging are playing an increasing role in the evaluation of small bowel disorders. Several studies have shown the advantage of these techniques over tradition barium fluoroscopic examinations secondary to improvements in spatial and temporal resolution combined with improved bowel distending agents. The preference of MR vs. CT has been geographical and based on expertise and public policy. With the increasing awareness of radiation exposure, there has been a more global interest in implementing techniques that either reduce or eliminate radiation exposure [Brenner DJ, Hall EJ. Computed tomography--an increasing source of radiation exposure. N Engl J Med 2007;357:2277-84]. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime or in studies that require sequential imaging time points such as in assessment of gastrointestinal motility [Froehlich JM, Patak MA, von Weymarn C, Juli CF, Zollikofer CL, Wentz KU. Small bowel motility assessment with magnetic resonance imaging. J Magn Reson Imaging 2005;21:370-75]. A recent study showed that certain subgroups of patients with Crohn's disease may be exposed to higher doses of radiation; those diagnosed at an early age, those with upper tract inflammation, penetrating disease, requirement of intravenous steroids, infliximab or multiple surgeries [Desmond AN, O'Regan K, Curran C, et al. Crohn's disease: factors associated with exposure to high levels of diagnostic radiation. Gut 2008;57:1524-29]. Therefore it has been suggested that techniques that can reduce or eliminate radiation exposure should be considered for imaging [Brenner DJ, Hall EJ. Computed tomography--an increasing source of radiation exposure. N Engl J Med 2007;357:2277-84]. Owing to the excellent softtissue contrast, direct multiplanar imaging capabilities, new ultrafast breath-holding pulse sequences, lack of ionizing radiation and availability of a variety of oral contrast agents, MR is well suited to play a critical role in the imaging of small bowel disorders. In this article we will review the technical issues related to the performance of MR enterography and enteroclysis and discuss the role and controversies of using MR in the assessment of inflammatory bowel disease.
针对小肠成像优化的磁共振成像（MR）和计算机断层扫描（CT）技术在小肠疾病评估中发挥着越来越重要的作用。多项研究表明，由于空间和时间分辨率的提高以及更好的肠道扩张剂，这些技术相对于传统的钡剂荧光透视检查具有优势。对MR和CT的偏好因地域、专业知识和公共政策而异。随着对辐射暴露的认识不断提高，全球对采用减少或消除辐射暴露的技术的兴趣日益浓厚[布伦纳DJ，霍尔EJ。计算机断层扫描——辐射暴露的一个日益增加的来源。《新英格兰医学杂志》2007年；357:2277 - 2284]。这在患有慢性疾病（如炎症性肠病）的患者中尤为重要，这些患者一生中可能需要多次检查，或者在需要连续成像时间点的研究中（如评估胃肠动力）[弗勒利希JM，帕塔克MA，冯·魏玛恩C，朱利CF，佐利科夫CL，温茨KU。磁共振成像评估小肠动力。《磁共振成像杂志》2005年；21:370 - 375]。最近一项研究表明，某些克罗恩病患者亚组可能受到更高剂量的辐射；那些在早年被诊断出的患者、患有上消化道炎症的患者、穿透性疾病患者、需要静脉注射类固醇、英夫利昔单抗或多次手术的患者[德斯蒙德AN，奥里根K，柯伦C等。克罗恩病：与高水平诊断性辐射暴露相关的因素。《胃肠病学》2008年；57:1524 - 1529]。因此，有人建议在成像时应考虑采用能减少或消除辐射暴露的技术[布伦纳DJ，霍尔EJ。计算机断层扫描——辐射暴露的一个日益增加的来源。《新英格兰医学杂志》2007年；357:2277 - 2284]。由于具有出色的软组织对比度、直接多平面成像能力、新的超快速屏气脉冲序列、无电离辐射以及多种口服造影剂的可用性，MR非常适合在小肠疾病成像中发挥关键作用。在本文中，我们将回顾与MR小肠造影和小肠灌肠相关的技术问题，并讨论在炎症性肠病评估中使用MR的作用及争议。
