Wårdell K, Braverman I M, Silverman D G, Nilsson G E
Department of Biomedical Engineering, Linköping University, Sweden.
Microvasc Res. 1994 Jul;48(1):26-38. doi: 10.1006/mvre.1994.1036.
Spatial and temporal variations in forearm skin perfusion captured by laser Doppler perfusion imaging (LDI) have been compared with topographic maps recorded by laser Doppler flowmetry. In order to determine the shortest LDI sampling time required at each measurement site, with an adequate signal-to-noise ratio and with the ability to display the heterogeneity in skin perfusion, the noise-limited resolution of the LDI system as well as various sampling times were tested. The noise-limited resolution for medium and high light intensities were less than 0.5% (temporal) and 0.3% (spatial) of full scale. A sampling time of 1 sec was selected and image presentation was made by performing bilinear interpolation between perfusion values. The same area (10 x 10 mm) was mapped with LDI and topographic mapping at seven different sites. In addition, a larger area covering the surrounding skin was recorded with LDI. The small area recordings with LDI and topographic mapping could be identified in the larger LDI image. High-and low-perfusion spots coincided between the two systems. Temporal variations were studied by repeated LDI recordings of the same areas as above. Small spots were selected in the areas and plotted versus time. Without provocation, the total perfusion changes at each spot showed large variations, but the relative perfusion levels between neighboring spots persisted. Provocation with heat increased the perfusion in all spots.
通过激光多普勒灌注成像（LDI）捕捉到的前臂皮肤灌注的空间和时间变化，已与激光多普勒血流仪记录的地形图进行了比较。为了确定在每个测量部位所需的最短LDI采样时间，同时具备足够的信噪比并能够显示皮肤灌注的异质性，对LDI系统的噪声限制分辨率以及各种采样时间进行了测试。中高强度下的噪声限制分辨率小于满量程的0.5%（时间）和0.3%（空间）。选择1秒的采样时间，并通过在灌注值之间进行双线性插值来进行图像呈现。在七个不同部位用LDI和地形图绘制相同区域（10×10毫米）。此外，用LDI记录覆盖周围皮肤的更大区域。LDI的小区域记录和地形图绘制可以在更大的LDI图像中识别出来。两个系统之间高灌注和低灌注点相吻合。通过对上述相同区域进行重复LDI记录来研究时间变化。在这些区域中选择小斑点并绘制其随时间的变化。在没有刺激的情况下，每个斑点的总灌注变化显示出很大差异，但相邻斑点之间的相对灌注水平保持不变。热刺激会增加所有斑点的灌注。
