Dachman Abraham H, Dawson Damien O, Lefere Philippe, Yoshida Hiro, Khan Nasreen U, Cipriani Nicole, Rubin David T
Department of Radiology, The University of Chicago, MC 2026, 5841 S. Maryland Ave, Chicago, IL 60637, USA.
Abdom Imaging. 2007 Jan-Feb;32(1):96-104. doi: 10.1007/s00261-006-9044-9. Epub 2006 Sep 13.
We performed a pilot study examining the feasibility of a new unprepped CT colonography (CTC) strategy: low fiber diet and tagging (unprepped) vs. low fiber diet, tagging and a magnesium citrate cleansing preparation (prepped). Prior reports of tagging were limited in that the residual stool was neither measured and stratified by size nor did prior reports subjectively evaluate the ease of interpretation by a reader experienced in interpreting CTC examinations.
Prospective randomized to unprepped n = 14 and prepped n = 14. Colonic segments were subjectively evaluated for residual stool that would potentially interfere with interpretation. Scores were given in the following categories: percentage of residual stool that was touching or nearly touching mucosa, the largest piece of retained stool, effectiveness of tagging, height of residual fluid, degree of distention, ease of interpretation, and reading time.
Ease of the CT read (scale where 4 = optimal read) averaged 1.3 for the unprepped group and 2.3 for the prepped group. The mean read time averaged 17.5 min for unprepped and 17.9 min for prepped. The degree of distention (scale where 4 = well distended) averaged 3.7 for unprepped and 3.6 for prepped. Supine and prone images combined, the unprepped group had 160 segments with stool; prepped group had 58 segments. The amount of stool covering the mucosa in all segments averaged 1.6 (33%-66% coverage) in the unprepped group and 0.35 (<33% mucosal coverage) in the prepped group. The mean size of the largest piece of stool was 33.67 mm for unprepped and 4.01 mm for prepped. Percentage of tagged stool was not significantly different between the groups (range of 94-98%). The height of residual fluid averaged 8.37 mm for unprepped and 13.4 mm for prepped. Three polyps in three patients were found during optical colonoscopy (OC) in the unprepped group (5, 6, and 10 mm), none of which were prospectively detected at CTC. Three polyps in three patients were detected during OC in the prepped group (5, 10, and 15 mm), two of which were prospectively detected at CTC. Two false-positive lesions were observed at CTC in one patient in the prepped group.
There was more stool in the unprepped group and while this factor did not slow down the reading time, it made the examination subjectively harder to interpret and likely caused the three polyps in this group to be missed. We conclude that a truly unprepped strategy that leaves significant residual stool, even if well tagged, is not desirable.
我们进行了一项初步研究，以检验一种新的未准备肠道的CT结肠成像（CTC）策略的可行性：低纤维饮食和标记（未准备肠道）与低纤维饮食、标记及柠檬酸镁清洁准备（准备肠道）的对比。先前关于标记的报告存在局限性，即未对残留粪便进行大小测量和分层，且先前报告也未由有CTC检查解读经验的读者对解读的难易程度进行主观评估。
前瞻性随机分为未准备肠道组（n = 14）和准备肠道组（n = 14）。对结肠段进行主观评估，以确定可能干扰解读的残留粪便。评分分为以下几类：接触或几乎接触黏膜的残留粪便百分比、残留粪便最大块的大小、标记效果、残留液体高度、扩张程度、解读难易程度和阅读时间。
CT解读的难易程度（4分为最佳解读），未准备肠道组平均为1.3分，准备肠道组平均为2.3分。未准备肠道组的平均阅读时间为17.5分钟，准备肠道组为17.9分钟。扩张程度（4分为充分扩张），未准备肠道组平均为3.7分，准备肠道组为3.6分。仰卧位和俯卧位图像合并后，未准备肠道组有160个含粪便的节段；准备肠道组有58个节段。未准备肠道组所有节段覆盖黏膜的粪便量平均为1.6（覆盖33%-66%），准备肠道组为0.35（黏膜覆盖<33%）。未准备肠道组残留粪便最大块的平均大小为33.67毫米，准备肠道组为4.01毫米。两组标记粪便的百分比无显著差异（范围为94%-98%）。未准备肠道组残留液体高度平均为8.37毫米，准备肠道组为13.4毫米。未准备肠道组在光学结肠镜检查（OC）中发现3例患者有3个息肉（5毫米、6毫米和10毫米），在CTC检查中均未前瞻性检测到。准备肠道组在OC中发现3例患者有3个息肉（5毫米、10毫米和15毫米），其中2个在CTC检查中被前瞻性检测到。准备肠道组有1例患者在CTC检查中出现2例假阳性病变。
未准备肠道组的粪便更多，虽然这个因素没有减慢阅读时间，但主观上使检查更难解读，可能导致该组的3个息肉漏诊。我们得出结论，即使标记良好，但留下大量残留粪便的真正未准备肠道策略是不可取的。
