The Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia.
Department of Gastroenterology and Surgery, Flinders Medical Centre, Adelaide, Australia.
Neurogastroenterol Motil. 2019 Feb;31(2):e13488. doi: 10.1111/nmo.13488. Epub 2018 Oct 7.
High-resolution impedance manometry (HRIM) catheters are used for esophageal reflux and bolus transit studies. Usually, these catheters have electrodes spaced at 20 mm intervals that are used for measuring electrical impedance between the consecutive electrodes and pressure sensors with 10 mm separation. Electrical impedance is a distributed measurement between the electrodes, unlike the point measurement of pressure sensors. Thus, the electrode separations affect the overall spatiotemporal resolution of the measurement.
A 3D model of the gastrointestinal tract, in which bolus shape and size can be modified, was used to simulate the admittance signal response of an intraluminal impedance catheter with 10 and 20 mm electrode separation to study the distributed sensitivity in the lumen to gain insight on the impedance measurement. In addition, experiments on sections of rabbit proximal colon were conducted with two catheters with electrode separations of 10 and 20 mm to compare the experimental data with the simulated data.
Reducing electrode spacing from 20 to 10 mm increased sensitivity to diameter change by a factor of ten. Admittance and diameter correlated strongly during a myogenic contraction with a Pearson's Correlation Coefficient of 0.86 for the custom catheter, in comparison with 0.56 for the commercial HRIM catheter.
Ten millimeter electrode separation has a better spatiotemporal resolution, and unlike 20 mm electrode separation is able to identify myogenic contractions. Based on the numerical and experimental data, closer electrode separation should be considered for improved spatial resolution.
高分辨率阻抗测压（HRIM）导管用于食管反流和食团转运研究。通常，这些导管的电极间隔为 20mm，用于测量连续电极之间的电阻抗和 10mm 间隔的压力传感器。电阻抗是电极之间的分布式测量，而不同于压力传感器的点测量。因此，电极间隔会影响测量的整体时空分辨率。
使用胃肠道的 3D 模型，可以修改食团的形状和大小，模拟具有 10mm 和 20mm 电极间隔的腔内阻抗导管的导纳信号响应，以研究腔内分布式灵敏度，从而深入了解阻抗测量。此外，还对兔近端结肠的切片进行了实验，使用两种电极间隔为 10mm 和 20mm 的导管，将实验数据与模拟数据进行比较。
将电极间隔从 20mm 减小到 10mm，可将直径变化的灵敏度提高 10 倍。在肌源性收缩期间，导纳和直径之间的相关性很强，定制导管的 Pearson 相关系数为 0.86，而商业 HRIM 导管为 0.56。
10mm 电极间隔具有更好的时空分辨率，与 20mm 电极间隔不同，它能够识别肌源性收缩。基于数值和实验数据，应考虑更接近的电极间隔以提高空间分辨率。
