Reliability of a close-range photogrammetry technique to measure ankle kinematics during active range of motion in place

BackgroundAs the risk of ankle turn during daily activity is very high, studying ankle kinematics in place is important for ankle sprain prevention. The close-range photogrammetry (CRP) technique is used to measure ankle kinematics during active range of motion (AROM) in place. The purpose of the study was to assess the reliability of CRP to measure ankle kinematics.MethodsTwenty adults were recruited and fourteen retro-reflective targets were mounted on the skin of their right feet. Imaging sensors were self-calibrated using a bundle adjustment technique, and the images were downloaded with Australis photogrammetric software. Three trials were conducted and reliability coefficients were used to assess agreement between them.ResultsReliability was almost perfect and the results show that the intraclass correlation coefficient (ICC) of ankle angle values were (dorsiflexion = 0.96), (plantarflexion = 0.81), (inversion = 0.92), (eversion = 0.95), (internal rotation = 0.92), and (external rotation = 0.78). The overall intraclass correlation coefficient was 0.89 and the standard error of the measurement (SEM) values ranged from (0.37° to 6.18°).ConclusionsThe results indicate that the CRP technique was able to reliably measure ankle kinematics. The results may support and enhance knowledge related to ankle AROM in the clinical arena.     

ABNORMAL CORNEAS MEASURED BY A NEW PHOTOGRAMMETRIC TECHNIQUE

The limitations of keratometry and photokeratoscopy are briefly discussed. A new photogrammetric technique of measuring corneal topography is described. Contours and cross-sections of abnormal corneas are presented to illustrate the scope and application of the new technique.     

Predicting the presence and severity of obstructive sleep apnea based on mandibular measurements using quantitative analysis of facial profiles via three-dimensional photogrammetry

BackgroundIn obstructive sleep apnea (OSA), the upper airway is obstructed during sleep due to obesity and/or posterior collapse of the tongue root. Maxillofacial morphological abnormalities increase the risk of OSA in the Asian population. This study sought to elucidate whether three-dimensional (3D) photogrammetry measurements correlate with the severity of OSA irrespective of sex and degree of obesity.MethodsA prospective pilot study was performed, in which 37 consecutive adult patients (M/F = 28/9) underwent polysomnography and 3D photogrammetry in the supine position for the diagnosis of OSA. Measurements obtained from 3D photogrammetry included mandibular width (Mw), mandibular length (Ml), mandibular depth (Md), mandibular width–length angle (Mwla), and mandibular area (Ma). The effects of sex and body mass index (BMI) on the measurements and their association with the apnea–hypopnea index (AHI) were statistically analyzed. The inter-rater reliability of the measurements was evaluated using intraclass correlation coefficients (ICC).ResultsMwla (R = 0.73, p < 0.01), Mw (R = 0.39, p < 0.05), and Md (R = ?0.34, p < 0.05) were significantly correlated with the severity of OSA. On multivariate analysis, Mwla (p < 0.01) and Md (p < 0.05) remained independent factors for AHI after adjusting for sex, age, BMI, and neck circumference. In addition, diagnosability analysis revealed that Mwla was useful for identifying the presence of OSA (AHI ≥5) (cutoff: 78.6°, sensitivity: 0.938, specificity: 0.800, area under the curve: 0.931). The ICC was >0.9, showing high reliability.ConclusionsThis study suggests that Mwla measured using 3D photogrammetry can predict the presence of OSA and correlates with the severity of OSA, independent of obesity and sex.     

Morphometric analysis of facial landmark data to characterize the facial phenotype associated with fetal alcohol syndrome

Procrustes analysis and principal component analysis were applied to stereo-photogrammetrically obtained landmarks to compare the facial features associated with fetal alcohol syndrome (FAS) in subjects with FAS and normal controls. Two studies were performed; both compared facial landmark data of FAS and normal subjects, but they differed in the number of landmarks chosen. The first study compared landmarks representing palpebral fissure length, upper lip thinness and philtrum smoothness and revealed no significant difference in shape. The second study added to the landmarks used in the first those affected by mid-face hypoplasia, and revealed significant differences in shape between the two groups, broadly confirming the FAS gestalt reported in the literature. Some disagreement in the characteristic FAS facial shape between our results and those reported in the literature may be due to ethnic variation.     

动态颈神经根管率的X线片测量

目的　应用新的颈椎斜位X线片测量方法测量颈神经根管矢状径、动态颈神经根管矢状径率 ,确定诊断神经根管狭窄敏感指标。方法　取 2 0 0名不同年龄段的成人摄取颈椎动态斜位X线片 (斜位、过伸斜位、过屈斜位 ) ,测量动态神经根管的矢状径 (a )、椎体斜位矢状径 (b )、计算颈神经根管率 (a/b )。分年龄、性别及组别进行统计分析。结果　①同一节段不同年龄、不同性别颈神经根管率差异无统计学意义。②不同组别动态颈神经根管率差异有非常显著性 (P <0 .0 1)。结论　①动态神经根管率是诊断神经根型颈椎病有效和敏感指标。②颈椎动态神经根管率 95 %理想值范围底限为 0 .30。颈椎动态神经根管率≤ 0 .30时应考虑颈神经根管狭窄     

利用数码照片重建颌面部软组织三维形态的初步研究

目的:探索面部软组织三维重建的新方法。方法:采用数码相机获取被摄者两张正面数码照片,利用数字化近景摄影测量的原理和方法,在地理信息系统下进行面部软组织的三维重建。结果:实现了颌面部软组织三维重建,获得了逼真的面部软组织三维图像。结论:利用数字化近景摄影测量和地理信息系统的原理和技术,进行颌面部软组织三维重构,是软组织三维重建方法的新探索。     

Implementation and application of real-time motion analysis based on passive markers

A method for real-time motion analysis based on passive markers is presented. An opto-electronic automatic motion analyser was used as hardware platform and the real-time operation was based on the interfacing between two levels of the system architecture. True real-time acquisition, processing and representation of two-dimensional and three-dimensional kinematics data were implemented through a newly conceived data acquisition procedure and high speed optimisation of the kinematics data processing. The method allows one to operate the motion analysis system in real-time; even when the data elaboration unit is required to perform other processing functions, the only consequence is a decrease in system sampling rate. The maximum number of processed and ploted markers in three dimensions at the highest system sampling rate (100 Hz) turned out to be suitable for the implementation of analytical and visual kinematics biofeedback. An example of the achievable level of complexity in terms of marker disposition model and graphic representation is reported by describing a demonstration of the real-time representation of human face movements. A clinical application of the method for patient position definition and control at radiotherapy units is presented.     

成人腰椎X线影像计量学参数测量与退行性腰椎管狭窄症关系的研究

用图像分析仪（MOP－videoplan）描记、测量了135名成人腰椎椎管造影X线片，70名腰椎正常，65名患有退行性腰椎管狭窄症，并计算了椎体体积和硬脊膜囊容积。数据表明，男性每个椎体的理想圆柱体体积与年龄显著相关，而女性则无相关；每个椎管的理想三棱柱形容积，男女均与年龄显著负相关。这可能与退行性腰椎管狭窄症的发病有关。而女性椎体体积与年龄无明显相关，可能是女性免于椎体好发压缩性骨折的自我保护机制。