Zötterman Johan, Mirdell Robin, Horsten Sandra, Farnebo Simon, Tesselaar Erik
Department of Hand Surgery, Plastic Surgery and Burns and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
PLoS One. 2017 Mar 30;12(3):e0174703. doi: 10.1371/journal.pone.0174703. eCollection 2017.
Laser Speckle Contrast Imaging (LSCI) is a non-invasive and fast technique for measuring microvascular blood flow that recently has found clinical use for burn assessment and evaluation of flaps. Tissue motion caused by for example breathing or patient movements may however affect the measurements in these clinical applications, as may distance between the camera and the skin and tissue curvature. Therefore, the aims of this study were to investigate the effect of frame rate, number of frames/image, movement of the tissue, measuring distance and tissue curvature on the measured perfusion.
Methyl nicotinate-induced vasodilation in the forearm skin was measured using LSCI during controlled motion at different speeds, using different combinations of frame rate and number of frames/image, and at varying camera angles and distances. Experiments were made on healthy volunteers and on a cloth soaked in a colloidal suspension of polystyrene microspheres.
Measured perfusion increased with tissue motion speed. The relation was independent of the absolute perfusion in the skin and of frame rate and number of frames/image. The measured perfusion decreased with increasing angles (16% at 60°, p = 0.01). Measured perfusion did not vary significantly between measurement distances from 15 to 40 cm (p = 0.77, %CV 0.9%).
Tissue motion increases and measurement angles beyond 45° decrease the measured perfusion in LSCI. These findings have to be taken into account when LSCI is used to assess moving or curved tissue surfaces, which is common in clinical applications.
激光散斑对比成像（LSCI）是一种用于测量微血管血流的非侵入性快速技术，最近已在烧伤评估和皮瓣评估中得到临床应用。然而，例如呼吸或患者移动引起的组织运动可能会影响这些临床应用中的测量结果，相机与皮肤之间的距离以及组织曲率也可能产生影响。因此，本研究的目的是探讨帧率、每幅图像的帧数、组织运动、测量距离和组织曲率对所测量灌注的影响。
在不同速度的受控运动过程中，使用不同的帧率和每幅图像帧数组合，并在不同的相机角度和距离下，通过LSCI测量前臂皮肤中烟碱甲酯诱导的血管舒张。对健康志愿者以及浸泡在聚苯乙烯微球胶体悬浮液中的一块布进行了实验。
所测量的灌注随组织运动速度增加而增加。这种关系与皮肤中的绝对灌注、帧率和每幅图像的帧数无关。所测量的灌注随角度增加而降低（60°时降低16%，p = 0.01）。在15至40厘米的测量距离之间，所测量的灌注没有显著差异（p = 0.77，%CV 0.9%）。
组织运动增加以及超过45°的测量角度会降低LSCI中所测量的灌注。在使用LSCI评估移动或弯曲的组织表面时，必须考虑这些发现，这在临床应用中很常见。
