Otis Linda L, Piao Daquing, Gibson Carolyn W, Zhu Quing
Department of Oral Medicine, The University of Pennsylvania School of Dental Medicine, Philadelphia 19104-6030, USA.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004 Aug;98(2):189-94. doi: 10.1016/j.tripleo.2004.03.030.
Changes in the oral microvasculature occur in a variety of diseases. Optical Doppler tomography (ODT) combines laser Doppler flowmetry with optical coherence tomography (OCT) to produce high-resolution tomographic images of biological tissues that also detect the velocity and direction of blood flow. The objective of this study was to determine the feasibility of ODT to image labial blood flow. A prototype ODT imaging system was constructed that characterized and measured labial blood flow in healthy subjects.
A prototype ODT instrument was constructed using a diode light source with a central wavelength of 1300 nanometers, a 40-nanometer spectral width and 2.4 microwatts output power. To verify the accuracy of the system, the flow rates of a phantom material (Intralipid) pumped through a capillary tube at various speeds was measured. To evaluate the clinical feasibility of the ODT prototye, the mucosal aspect of the upper and lower lips at the midline was imaged in 9 healthy volunteers. The sample arm of the instrument consisted of a fiberoptic probe with a 2-mm in diameter polished glass lens attached to the end. The probe was placed approximately 3 mm from the mucosal surface of the lip and oriented perpendicular to the surface. A motorized translation stage moved the fiber in a superior to inferior direction while the subject's head was stabilized by placing the chin into a chin rest. Imaging time for a 12-mm x 2.5-mm scan was approximately 64 seconds.
The phantom experiments revealed that accuracy of this novel ODT prototype to measure flow was within 5%. In vivo labial blood flow velocity ranged from 11.8 to 43.1 mm/second in the upper lip and 8.2 to 53.2 mm/second in the lower lip. There were no statistically significant differences between flow rates in the upper and lower lips. OCT images and Doppler velocity signals were successfully integrated producing in vivo images of labial blood in all of the subjects (15 images). The resulting cross-sectional images revealed microscopic details of labial structures and, to the best of our knowledge, are the first ODT images of the labial microvasculature.
The results of this in vivo study prove the feasibility of ODT to quantify labial blood flow and produce high spatial resolution images specifically localizing vessels anatomically. ODT provides both flow speed and flow direction information. ODT is noninvasive and offers the advantages of high volumetric flow sensitivity.
口腔微血管的变化会在多种疾病中出现。光学多普勒断层扫描（ODT）将激光多普勒血流仪与光学相干断层扫描（OCT）相结合，以生成生物组织的高分辨率断层图像，同时还能检测血流的速度和方向。本研究的目的是确定ODT对唇部血流进行成像的可行性。构建了一个原型ODT成像系统，用于对健康受试者的唇部血流进行特征描述和测量。
使用中心波长为1300纳米、光谱宽度为40纳米、输出功率为2.4微瓦的二极管光源构建了一个原型ODT仪器。为验证系统的准确性，测量了以不同速度通过毛细管泵送的模拟材料（英脱利匹特）的流速。为评估ODT原型的临床可行性，对9名健康志愿者上唇和下唇中线处的黏膜面进行了成像。仪器的样品臂由一个末端连接有直径2毫米抛光玻璃透镜的光纤探头组成。探头放置在距离唇部黏膜表面约3毫米处，并垂直于表面。当受试者的头部通过将下巴放入下巴托中得以稳定时，一个电动平移台使光纤上下移动。一次12毫米×2.5毫米扫描的成像时间约为64秒。
模拟实验表明，这款新型ODT原型测量血流的准确性在5%以内。上唇的体内唇部血流速度范围为11.8至43.1毫米/秒，下唇为8.2至53.2毫米/秒。上唇和下唇的血流速度之间无统计学显著差异。OCT图像和多普勒速度信号成功整合，为所有受试者（共15幅图像）生成了唇部血液的体内图像。所得的横截面图像揭示了唇部结构的微观细节，据我们所知，这是唇部微血管系统的首批ODT图像。
这项体内研究的结果证明了ODT对唇部血流进行定量以及生成能在解剖学上明确血管位置的高空间分辨率图像的可行性。ODT可提供血流速度和血流方向信息。ODT是非侵入性的，具有高体积血流敏感性的优势。
