结肠息肉：标记液体衰减和观察窗对息肉显见度及测量的影响——猪结肠标本的体外实验

Colonic polyps: effect of attenuation of tagged fluid and viewing window on conspicuity and measurement--in vitro experiment with porcine colonic specimen.

作者信息

Slater Andrew, Taylor Stuart A, Burling David, Gartner Louise, Scarth Julia, Halligan Steve

机构信息

Department of Intestinal Imaging, St. Mark's Hospital, London, England.

出版信息

Radiology. 2006 Jul;240(1):101-9. doi: 10.1148/radiol.2401050984.

DOI:10.1148/radiol.2401050984

PMID:16793973

Abstract

PURPOSE

To investigate effect of attenuation of tagged fluid and viewing window on polyp conspicuity and measurement with porcine colonic specimen.

MATERIALS AND METHODS

Eleven (3-10-mm-diameter) polyps were created in porcine colon and the specimen submerged in saline. Four-detector row CT was performed after gas distension and after filling with six barium sulfate suspensions (attenuation, 100-1000 HU). Two readers independently measured maximal two-dimensional polyp diameter on each data set with the following four viewing windows and window levels and window widths, respectively: colon (-150 HU, 1500 HU), lung (-500 HU, 1500 HU), bone (500 HU, 2500 HU), and abdomen (40 HU, 400 HU). In consensus, polyp conspicuity (compared with air data set) was assigned a grade of 1-4 for each viewing window (grade 1, not seen or barely visible; grade 4, optimally seen). For statistical analysis, conspicuity grades were collapsed to a two-point scale. Data were analyzed with Mann-Whitney, Kruskal-Wallis, and chi2 tests.

RESULTS

Accuracy of polyp measurement was independent of viewing window for attenuation of tagged fluid of 100-300 HU but differed significantly for 500-1000 HU (P < .001); that for colonic and bone viewing windows was superior (median size difference, 1.0 mm; interquartile range, 0.5-1.5). Conspicuity differed significantly according to viewing window at all attenuation values (P < .001). For 100-300 HU with abdominal viewing window, 83% (24 of 29) of observations were assigned grade 3 or 4 (best). For 500-1000 HU with bone viewing window, 94% (30 of 32) of observations were assigned grade 3 or 4 (superior). Overall conspicuity was best with bone viewing windows at 700 HU.

CONCLUSION

Polyp conspicuity and measurement in tagged data sets were optimized at 700 HU with bone viewing windows. At less than 300 HU, conspicuity improved with abdominal viewing windows.

摘要

目的

研究标记液体衰减和观察窗对猪结肠标本中息肉显示清晰度及测量的影响。

材料与方法

在猪结肠内制造11个直径为3 - 10毫米的息肉，将标本浸入盐水中。在气体扩张后以及用六种硫酸钡悬浮液（衰减值为100 - 1000 HU）充盈后进行四排探测器CT扫描。两名阅片者分别在以下四个观察窗以及窗位和窗宽条件下，独立测量每个数据集中息肉的最大二维直径：结肠（-150 HU，1500 HU）、肺（-500 HU，1500 HU）、骨（500 HU，2500 HU）和腹部（40 HU，400 HU）。经共识，每个观察窗的息肉显示清晰度（与空气数据集相比）被分为1 - 4级（1级，未见或几乎不可见；4级，显示最佳）。为进行统计分析，将显示清晰度等级合并为两点量表。数据采用Mann - Whitney检验、Kruskal - Wallis检验和卡方检验进行分析。

结果

对于标记液体衰减值为100 - 300 HU的情况，息肉测量的准确性与观察窗无关，但对于500 - 1000 HU的情况则有显著差异（P <.001）；结肠和骨观察窗的测量准确性更高（中位数尺寸差异为1.0毫米；四分位间距为0.5 - 1.5）。在所有衰减值下，显示清晰度根据观察窗的不同有显著差异（P <.001）。对于衰减值为100 - 300 HU且采用腹部观察窗的情况，83%（29例中的24例）的观察结果被评为3级或4级（最佳）。对于衰减值为500 - 1000 HU且采用骨观察窗的情况，94%（32例中的30例）的观察结果被评为3级或4级（更优）。总体而言，在700 HU时骨观察窗的显示清晰度最佳。