Kerker J, Albes G, Roer N, Montag M, Budde T, Schaefer A
Klinik für Innere Medizin I, Abteilung für Gastroenterologie und Hepatologie, Alfried-Krupp-Krankenhaus, Essen.
Z Gastroenterol. 2008 Apr;46(4):339-43. doi: 10.1055/s-2007-963774.
Besides conventional colonoscopy, CT and MR colonography offer alternate virtual imaging modalities of the colon. The sensitivity of CT colonography, which is associated with radiation exposure, has been published in prior, large studies. Regarding MR colonography, in particular dark lumen MR colonography with the rectal administration of a water enema as a contrast agent, only limited published data exist. The goal of this study was to compare MR colonography with conventional colonoscopy in the detection of colorectal polyps. In addition the feasibility and image quality in unselected hospitalised patients were assessed.
PATIENTS/METHODS: Included were 103 hospitalised patients who had to undergo colonoscopy for various indications. Immediately prior to conventional colonoscopy, MR colonography with rectal water enema and additional intravenous administration of contrast material was performed. Detection rates for polyps and adenomas were documented with both imaging modalities. Image quality and completion rates (practicability) and other (incidental) findings were also recorded.
In 15 of 103 patients the MR examination could not be done or was only partially completed. The detection rate of MR colonography for polyps (adenomas) was 2% (4%) for polyps (adenomas) up to 5 mm in diameter, 38% (56%) for polyps (adenomas) 6-10 mm in diameter and 89% (89%) for polyps (adenomas) up to 11 mm in diameter. One flat carcinoma seen with conventional coloscopy was missed on MR colonography.
MR colonography offers the possibility of imaging the colon without exposure to radiation. Polyps and adenomas are detected, similar to the detection rate of CT colonography, with adequate sensitivity only if they are larger than 10 mm in diameter. Therefore this imaging technique is not (yet) suitable as a screening test. Additional limitations are the necessary cooperation of the patient which can reduce the practicability and image quality in selected patients. Further studies like the just started German multicentre trial are needed to assess the position of MR colonography.
除了传统的结肠镜检查外，CT结肠成像和MR结肠成像提供了结肠的替代虚拟成像方式。CT结肠成像的敏感性与辐射暴露有关，此前已在大型研究中发表。关于MR结肠成像，特别是直肠注入水灌肠剂作为造影剂的暗腔MR结肠成像，仅有有限的已发表数据。本研究的目的是比较MR结肠成像与传统结肠镜检查在检测大肠息肉方面的效果。此外，还评估了未选择的住院患者中该检查的可行性和图像质量。
患者/方法：纳入了103例因各种适应证而需接受结肠镜检查的住院患者。在进行传统结肠镜检查前，立即进行直肠水灌肠并静脉注射造影剂的MR结肠成像。用两种成像方式记录息肉和腺瘤的检出率。还记录了图像质量、完成率（实用性）和其他（偶然）发现。
103例患者中有15例无法完成MR检查或仅部分完成。MR结肠成像对直径达5mm的息肉（腺瘤）的检出率为2%（4%），直径6 - 10mm的息肉（腺瘤）为38%（56%），直径达11mm的息肉（腺瘤）为89%（89%）。传统结肠镜检查发现的1例扁平癌在MR结肠成像中未被发现。
MR结肠成像提供了在不暴露于辐射的情况下对结肠进行成像的可能性。息肉和腺瘤的检出情况与CT结肠成像的检出率相似，只有当它们直径大于10mm时才有足够的敏感性。因此，这种成像技术目前还不适合作为筛查试验。其他局限性包括患者需要配合，这可能会降低特定患者的实用性和图像质量。需要进一步的研究，如刚刚启动的德国多中心试验，来评估MR结肠成像的地位。
