Gates’分析法测定肾小球滤过率的影响因素研究

Factors affecting the Gates' measurement of glomerular filtration rate

目的:探讨Gates’分析法测定肾小球滤过率(GFR)过程中的影响因素。方法:针对γ照相机或SPECT测定GFR中常见的影响因素,在规范操作的基础上人为改变某些因素,观察其对GFR值的影响。结果:身高值变化会引起GFR值反向的差异性变化,而体重值变化,GFR值出现同向的变化(P<0.01);注射前后注射器测量条件不一致,可影响结果的准确性:注射器放置的几何学位置会引起GFR值的偏差,尤其是注射后用错注射器进行测量,GFR值会出现明显的误差(P<0.01);注射时显像剂血管外渗漏,导致进入体内净计数的减低,会造成GFR值增高;图像处理时本底感兴趣区(ROI)位置对结果影响较大,其中位于外上方或内下方,所得GFR值明显降低(P<0.01)。结论:在用Gates’分析法测定GFR值的整个过程中,有诸多因素可影响到最终结果,尤其是药物注射的质量和本底ROI的选择,对GFR的测定值有着明显的影响,规范的操作才能获得较为准确可信的GFR值。

Objective: To investigate the factors that influenced the Gates' measurement of glomerular filtration rateGFR. Methods: Several factors were changed intentionally during conventional performance of renal dynamic scans and their effects on the GFR value were studied. Results: The GFR value decreased when an increased value of body height was input, while an increased GFR value would be observed after inputting a decreased value of body height. When changing the value of body weight, the GFR value had a synchronizing changeP<0.01. If the syringe before and after the scan were measured under different conditions, the GFR results may be inaccurate and vary in any of the following cases, i.e. selecting different geometrical positions of the syringe, or mistaking a different syringe for the same one used before the scan. The extravascular leakage of the injected radiopharmaceutical resulted in a decreased net injection dose and therefore an increased GFR value. The selection of a background ROI field had an apparent impact on the result. The GFR value decreased prominently when an upper lateral area to the renal was selected as a ROI fieldP<0.01. Conclusion: The Gates' analyzing results of GFR may be affected by several factors, of which special consideration should be taken for the quality of the injection and the choice of background ROI, which affect GFR value apparently. As a result, the technology of the operation must be normative to obtain an accurate and creditable GFR result.