Seibert D G
Department of Medicine, Robert C. Byrd Health Science Center, West Virginia University, Morgantown 26506-9161, USA.
Am J Gastroenterol. 1997 Sep;92(9):1510-4.
Because of variations in magnification, errors in stent selection may occur when stricture location is determined from fluoroscopic images or x-ray film.
An ERCP catheter with measurement markings was inserted 5, 7, and 10 cm into the bile duct in 30 patients without bile obstruction. Film measurements obtained at each depth were converted to actual distances using standard conversion as well as endoscope ratio conversion formulas. The site of obstruction in 52 patients with an obstructing lesion was measured with a ruled catheter, by a wire withdrawal technique, and using x-ray film. After a stent was selected on the basis of the catheter measurement, the accuracy of stent selection was determined for each method of measure.
Conversion of x-ray measurements to ruled catheter measurements obtained by insertions of 5, 7, and 10 cm using standard conversion factors yielded measurements of 4.9 +/- 0.9, 6.8 +/- 0.3, and 9.5 +/- 1.9 cm, respectively, with a correlation coefficient of r = 0.80. Ratio conversion yielded measurements of 0.5 +/- 0.8, 7 +/- 1.0, and 9.9 +/- 1.4, respectively, with a correlation coefficient of r = 0.88. Measurement of stricture location with the ruled catheter and then by wire withdrawal yielded a correlation coefficient of 0.98. When ruled catheter measurements were compared with the x-ray ratio conversions, the concordance dropped to 0.79. The ruled catheter and wire withdrawal were more accurate in predicting the location of the stent tip than x-ray film measurements (p < 0.001, Wilcoxon matched pairs). Of 52 stents selected, no errors in stent selection occurred when the ruled catheter was used (p < 0.001, Fisher's exact test), two errors occurred when wire withdrawal was used (p < 0.004), and 14 errors occurred when film measurements were used.
Use of a ruled catheter or wire withdrawal is much more accurate for selecting stents than use of x-ray film measurements.
由于放大倍数存在差异，在通过荧光镜图像或X光片确定狭窄部位时，可能会出现支架选择错误的情况。
将带有测量标记的内镜逆行胰胆管造影（ERCP）导管插入30例无胆管梗阻患者的胆管内5厘米、7厘米和10厘米处。使用标准换算公式以及内镜比例换算公式，将在每个深度获得的胶片测量值转换为实际距离。使用带刻度的导管、钢丝回撤技术以及X光片测量52例有梗阻性病变患者的梗阻部位。在根据导管测量结果选择支架后，确定每种测量方法选择支架的准确性。
使用标准换算系数将X光测量值转换为通过插入5厘米、7厘米和10厘米获得的带刻度导管测量值时，测量值分别为4.9±0.9厘米、6.8±0.3厘米和9.5±1.9厘米，相关系数r = 0.80。比例换算得出的测量值分别为0.5±0.8厘米、7±1.0厘米和9.9±1.4厘米，相关系数r = 0.88。先用带刻度的导管测量狭窄部位，然后用钢丝回撤法测量，得出的相关系数为0.98。当将带刻度导管测量值与X光比例换算值进行比较时，一致性降至0.79。与X光片测量相比，带刻度的导管和钢丝回撤法在预测支架尖端位置方面更准确（p < 0.001，Wilcoxon配对检验）。在所选的52个支架中，使用带刻度的导管时未出现支架选择错误（p < 0.001，Fisher精确检验），使用钢丝回撤法时出现了2个错误（p < 0.004），使用胶片测量时出现了14个错误。
与使用X光片测量相比，使用带刻度的导管或钢丝回撤法选择支架的准确性要高得多。
