Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises
Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises
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DOI：
10.1007/s12024-010-9171-z
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发表时间：
2010-12-01
影响因子：
1.8
通讯作者：
Langlois, Neil E. I.
中科院分区：
文献类型：
--
作者：
Hughes, Vanessa K.;Langlois, Neil E. I.
擦伤可能具有法医学意义，因此擦伤的年龄可能是一个重要的问题。这项研究试图确定比色法或反射分光光度法是否可以客观地估计瘀伤的年龄。基于前面描述的方法，使用装有光纤反射探头的Cary 100生物分光光度计从瘀伤中获得反射光谱扫描。测量是从瘀伤和对照区域进行的。使用软件计算490和480 nm处的一阶导数；使用等压点法计算含氧血红蛋白的比例，并使用软件应用程序将扫描数据转换为比色数据。此外，还记录了可能与确定擦伤年龄相关的因素的数据：受试者年龄、受试者性别、创伤程度、瘀伤大小、肤色、体型和瘀伤深度。对147名受试者进行了233次反射光谱扫描以进行分析。擦伤时间为0.5h~231.5 h，采用一般线性模型分析方法。这表明，对瘀伤黄度的比色测量占瘀伤年龄的13%。通过结合其他记录的数据(如上所述)，黄度可以预测擦伤年龄的32%-这意味着68%的变化取决于其他因素。然而，对该模型的批判性评估表明，确定瘀伤年龄的比色法受到肤色的影响，需要测量通过分光光度方法获得的含氧血红蛋白的比例。使用分光光度法，仅490 nm处的一阶导数就占擦伤年龄估计的18%。当在一般线性模型中包括其他因素(受试者性别、瘀伤深度和血红蛋白的含氧量)时，这一比例增加到31%，这意味着69%的变异依赖于其他因素。这表明在评估擦伤年龄时，分光光度法将比比色法更有用，但所用的分光光度法需要改进，以提供有关估计擦伤年龄的有用数据。这样的改进可能包括使用多个读数或利用皮肤光学的综合数学模型。
Bruises can have medicolegal significance such that the age of a bruise may be an important issue. This study sought to determine if colorimetry or reflectance spectrophotometry could be employed to objectively estimate the age of bruises. Based on a previously described method, reflectance spectrophotometric scans were obtained from bruises using a Cary 100 Bio spectrophotometer fitted with a fibre-optic reflectance probe. Measurements were taken from the bruise and a control area. Software was used to calculate the first derivative at 490 and 480 nm; the proportion of oxygenated hemoglobin was calculated using an isobestic point method and a software application converted the scan data into colorimetry data. In addition, data on factors that might be associated with the determination of the age of a bruise: subject age, subject sex, degree of trauma, bruise size, skin color, body build, and depth of bruise were recorded. From 147 subjects, 233 reflectance spectrophotometry scans were obtained for analysis. The age of the bruises ranged from 0.5 to 231.5 h. A General Linear Model analysis method was used. This revealed that colorimetric measurement of the yellowness of a bruise accounted for 13% of the bruise age. By incorporation of the other recorded data (as above), yellowness could predict up to 32% of the age of a bruise-implying that 68% of the variation was dependent on other factors. However, critical appraisal of the model revealed that the colorimetry method of determining the age of a bruise was affected by skin tone and required a measure of the proportion of oxygenated hemoglobin, which is obtained by spectrophotometric methods. Using spectrophotometry, the first derivative at 490 nm alone accounted for 18% of the bruise age estimate. When additional factors (subject sex, bruise depth and oxygenation of hemoglobin) were included in the General Linear Model this increased to 31%-implying that 69% of the variation was dependent on other factors. This indicates that spectrophotometry would be of more use that colorimetry for assessing the age of bruises, but the spectrophotometric method used needs to be refined to provide useful data regarding the estimated age of a bruise. Such refinements might include the use of multiple readings or utilizing a comprehensive mathematical model of the optics of skin.