Abstract

Osteonecrosis becomes a more widespread problem as the population is getting older. Current osteonecrosis diagnosis not only requires invasive procedures but also often leads to surgical replacement. This paper reports a preliminary study of applying optical coherence tomography (OCT) for noninvasive diagnosis of osteonecrosis using an endoscopic probe based on a microelectromechanical (MEMS) scanning mirror. The endoscopic MEMS probe is only 2.5 mm in diameter and can scan a field of view of 24°. First a tissue sample of femoral head with osteonecrosis is scanned with the MEMS probe. The resultant OCT images can clearly delineate the necrosis region from the normal bone. Then in vivo experiments are carried out on an adult rabbit, in which the rabbit’s femoral head is scanned and imaged with the same MEMS probe and both three-dimensional (3 D) structural images and blood flows are obtained. The OCT imaging experiments show that the femoral head of this rabbit does not have osteonecrosis and its blood flow is present, which is in agreement with the destructive diagnosis. The blood flow rates in the femoral head are extracted from the OCT images acquired in three cases: normal blood supply, partial ischemia and complete ischemia, which are 19.3 mm/s, 11.9 mm/s, and 1.88 mm/s, respectively. These experiments demonstrate that OCT can clearly distinguish between the osteonecrosis and normal bone and measure the blood flow rate in the bone, both with the cartilage present, showing great potential for non-invasive osteonecrosis diagnosis.

摘要

随着人口老龄化，骨坏死成为一个更普遍的问题。目前的骨坏死诊断不仅需要侵入性手术，而且还经常导致手术替代。本文报告了使用基于微机电 (MEMS) 扫描镜的内窥镜探针应用光学相干断层扫描 (OCT) 对骨坏死进行无创诊断的初步研究。内窥镜 MEMS 探头直径仅 2.5 毫米，可扫描 24° 的视野。首先用 MEMS 探针扫描股骨头坏死的组织样本。由此产生的 OCT 图像可以清楚地描绘出正常骨骼的坏死区域。然后在体内实验是在一只成年兔身上进行的，其中使用相同的 MEMS 探头对兔的股骨头进行扫描和成像，并获得三维 (3D) 结构图像和血流。OCT影像学实验显示，该兔股骨头未见骨坏死，有血流，与破坏性诊断相符。从三种情况下获取的OCT图像中提取股骨头的血流速率：正常血供、部分缺血和完全缺血，分别为19.3 mm/s、11.9 mm/s和1.88 mm/s。这些实验表明 OCT 可以清楚地区分骨坏死和正常骨骼，并测量骨骼中的血流量，两者都存在软骨，