脊椎三維運動幾何之深度影像量測方法開發與評估

Development and Evaluation of a Depth Image-Based Method for Measuring Kinematic Geometry of the Spine

吳志連(CHI LIN NG)

指導教授 ： 呂東武

國立臺灣大學/工學院/醫學工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201902307

摘要

人體脊椎是一個複雜及重要的結構，它保護脊髓和神經以及傳遞頭顱與軀幹的重量至骨盆，不正常之脊椎形態是會影響到正常生活，甚至影響健康，在臨床上脊椎的資訊主要以X光攝影是取得，幫助醫生對病患進行診斷、評估，治療以及未來復建的規劃，不過，使用X光攝影會讓病患暴露於放射線之下，若病患需長期接受X光攝影檢測，會增加罹患癌症的風險，因此X光攝影是無法對脊椎疾病進程及治療進行頻繁的監控和追蹤，另外X光攝影的使用空間受到限制，亦無法提供脊椎在動態過程中的三維空間中的運動幾何。因此開發不受時空限制、非侵入式且無放射線暴露的方式去量測脊椎的三維運動幾何實是一個重要的研究課題。
目前非侵入式且無放線射暴露的方式主要分為兩種，一種是藉由測量背部三維表面模型，透過背部的特徵點，如最表面之凸點、凹點、槽線和曲率等資訊重建出脊椎之模型，另一種則是使用脊椎測量儀，在背部的第七節頸椎 (7th Cervical Vertebrae，C7) 沿著槽線往下滑動至第四節腰椎 (5th Lumbar Vertebrae，L5) ，透過角度之變化去計算出脊椎之三維資訊。以上兩種方法雖然是非侵入式且無放線射之危害，但是只局限於靜態之脊椎三維資訊，本研究藉由已建立之脊椎模型及背部曲面之模型與使用Mircosoft kinect v2 之深度資料為基礎之影像方法重建出背部曲面，透過非剛體註冊 (Non-rigid Registration ) 之方法將兩背部曲面對準，計算出靜態及動態脊椎之三維型態。
在本研究中探討正常人的較大之軀幹動作的脊椎運動模式以及三維型態，包括步行 (Walking) 、跑步 (Running) 、單腳站立 (Standing on one leg)、從坐著到站站 (Sit to stand)、原地跳躍 (Jump in place) 和側向彎曲 (Lateral flexion) 等動作，可以計算出脊椎從中間姿勢 (Neutral position) 到不同動作過程的脊椎三維運動之變化，即時掌握動作的脊椎的瞬時型態。
本方法具有三維量測、不受時空限制和非侵入式、無輻射之性質，適用於在靜態和動態脊椎三維運動幾何之分析，如此可減少接射輻射傷害次數、快速篩檢、了解脊椎在各動作在瞬時的型態以及提供有效的脊椎資訊評估以供臨床人員使用。

關鍵字

脊椎型態 ； 非剛體註冊 ； 脊椎評估 ； 脊椎運幾何學 ； 深度影像 ； 動態脊椎

並列摘要

The spine is an important and complicated structure of the skeleton, which is composed of alternative vertebrae and intervertebral discs and supported by spinal ligaments and muscles. Spine protected the spinal cord and nerves, transmit the weight of the trunk and provide motion stability. Abnormal spine morphology can affect appearance, life and even affect health.
X-ray imaging serves as the ‘gold standard’ for the evaluation of spinal deformities or structural vertebral disorders in clinical, but it will increase the carcinogenic risks and harm patients’ health when exposing radiation. Therefore, X-ray cannot frequently monitor the spinal disorder and examine progression and treatment for the patients. In addition, the examining space is limited and it cannot provide the kinematic geometry of the spine in dynamic process. As such, it is important to develop the method of measuring the kinematic geometry of the spine that is not limited by time and space, non-invasively and non-radiating.
Currently, there are mainly two non-invasively and non-radiating method to measure spinal morphology. One is to reconstruct the three-dimensional surface of back and calculate the three-dimensional geometry of the spine through the feature points on the surface, such as bumps, pits, groove line and curvature of surface. The other one is to use the spinal gauge to slide on back from 7th Cervical vertebrae (C7) to 5th Lumbar vertebrae (L5) along the groove line.
This study is based on the established templates of the spine and back surface, and measured the back surface using Microsoft kinect v2. The templates of back surface align to the subject-specific back surface using non-rigid registration and calculate the kinematic geometry of the spine in static and dynamic process.
In this study, we explored the spinal movement patterns of normal subjects during different movements including walking, running, standing on one leg, sit-to-stand, jumping in place and lateral flexion.
The study has a three-dimensional measurement, no time-space limitation and non-invasive, non-radiative properties, and is suitable for analysis of three-dimensional motion geometry in static and dynamic spine, to reduce the numbers of radiation injuries and rapid screening. Each movement patterns are in instantaneous and provides an effective assessment of the spine in diagnosis.

並列關鍵字

Depth Image ； Free Form Deformation ； Spinal geometrical kinematics ； Diagnosis of spine ； Dynamic spine ； Spinal movement pattern ； Spinal motion

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