Mang Thomas G, Schaefer-Prokop Cornelia, Maier Andrea, Schober Ewald, Lechner Gerhard, Prokop Mathias
Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria.
AJR Am J Roentgenol. 2005 Dec;185(6):1582-9. doi: 10.2214/AJR.04.1519.
The objective of this phantom study was to determine the performance of MDCT colonography for the detection of small polyps under ideal imaging conditions and to determine the added value of 3D imaging when used as an adjunct to 2D imaging.
Thirty-six polypoid and 39 flat polyps (44 lesions, 2-5 mm; 31 lesions, 6-8 mm) were placed in three explanted segments of a thoroughly cleaned porcine colon (overall length, 4.5 m) that was distended with air and submerged in a water phantom. MDCT data sets with 4 x 1 mm collimation and 6-mm table feed were reconstructed every 0.7 mm with 1.25-mm effective slice width. The data were reviewed by three radiologists using 2D images in all three projections and with 3D volume-rendered images available as an adjunct to the 2D images.
Additional 3D as a problem-solving tool significantly increased the overall sensitivity (96% vs 90%), decreased the total number of false-positive calls (n = 9 vs n = 5), and increased the diagnostic confidence level (p < 0.03) compared with 2D images alone. Small polyps less than or equal to 5 mm (89% vs 95%, p = 0.004) and flat polyps (82% vs 94%, p = 0.001) especially benefited from 3D. Sensitivity was generally higher for polypoid than for flat polyps (99% vs 94%, p = 0.041).
Under phantom conditions, simulating an ideal clinical setup, MDCT colonography is not limited by spatial resolution and detects polyps less than or equal to 5 mm in size with high sensitivity and specificity. Additional 3D image tools improve diagnostic accuracy and reviewer confidence, especially for the detection of flat and small polyps.
本体模研究的目的是确定在理想成像条件下多层螺旋CT结肠成像检测小息肉的性能，并确定三维成像作为二维成像辅助手段的附加价值。
将36个息肉样息肉和39个扁平息肉（44个病变，2 - 5毫米；31个病变，6 - 8毫米）放置在一段彻底清洁的猪结肠的三个离体节段中（总长度4.5米），该结肠段充入空气并浸没在水模中。采用4×1毫米准直和6毫米床进速度采集多层螺旋CT数据集，以1.25毫米有效层厚每隔0.7毫米进行重建。三位放射科医生使用所有三个投影方向的二维图像，并将三维容积再现图像作为二维图像的辅助手段对数据进行评估。
与单独使用二维图像相比，额外使用三维图像作为问题解决工具可显著提高总体敏感度（96%对90%），减少假阳性诊断的总数（9例对5例），并提高诊断置信度（p < 0.03）。小于或等于5毫米的小息肉（89%对95%，p = 0.004）和扁平息肉（82%对94%，p = 0.001）尤其从三维成像中获益。息肉样息肉的敏感度一般高于扁平息肉（99%对94%，p = 0.041）。
在体模条件下，模拟理想的临床设置，多层螺旋CT结肠成像不受空间分辨率限制，能够以高敏感度和特异性检测大小小于或等于5毫米的息肉。额外的三维图像工具可提高诊断准确性和阅片者的置信度，尤其是对于扁平息肉和小息肉的检测。
