背景:从有和没有2型糖尿病(DM2)的个体的红外(IR)图像中提取的辐射信息的定量解释是一个尚待解决的问题。考虑到DM2是世界范围内的健康问题并且开始向糖尿病足病(DFD)发展,这是特别有价值的。由于DM2会引起血管和神经水平的变化,由于这种改变,外皮肤上的代谢热分布被改变。这种贡献特别令人感兴趣的是下肢皮肤热模式上显示的那些改变。这种改变的核心是导致全身体温调节的血管和神经网络的恶化。在这种情况下,IR成像被引入作为一种可能的辅助工具,以在足够早的阶段帮助DM2的临床诊断,以防止DFD的发展。
方法:下肢的红外图像是从一组临床诊断有和没有DM2的个体中获得的。患者的其他纳入标准应无任何可见伤口或组织相关创伤(例如,受伤,水肿,等等),也没有非代谢合并症。使用评估下肢温度分布的时空演变的指标对所有图像和数据进行同等处理和分析。我们研究了诱导外部刺激后个体腿的时间反应。为此,我们结合了不对称和热响应指数(ATR)和热响应指数(TRI)的信息,使用不同时间的图像计算,改善先前使用ATR和TRI分别获得的结果。
结果:提出了从具有和不具有DM2的个体的下肢红外图像中提取的信息的新颖表示。此表示是使用前视图和后视图(PV)的ATR和TRI指数构建的,单独和结合来自两种观点的信息。在所有情况下,每个索引和每个视图的信息呈现线性属性,允许所述信息在明确定义和有限的空间中被定量地解释。这个代表,建在极坐标空间中,允许获得86%的灵敏度值,97%,97%,特异性值为83%,72%,前视(AV)为78%,PV,以及合并后的观点,分别。此外,观察到,定义这个新表示空间的角度变量允许显着(p<0.01)区分组,虽然与感兴趣的临床变量相关,如葡萄糖和糖化血红蛋白。
结论:ATR和TRI指数之间存在的线性特性允许对从具有和不具有DM2的个体下肢的IR图像中提取的信息进行定量解释,并允许构建表示空间,以消除解释中可能的歧义,在简化它的同时,使其易于临床使用。
BACKGROUND: The quantitative interpretation of the radiometric information extracted from infrared (IR) images in individuals with and without type 2 diabetes mellitus (DM2) is an open problem yet to be solved. This is of particular value given that DM2 is a worldwide health problem and onset for evolution toward diabetic foot disease (DFD). Since DM2 causes changes at the vascular and neurological levels, the metabolic heat distribution on the outer skin is modified as a consequence of such alterations. Of particular interest in this contribution are those alterations displayed over the skin\'s heat patterns at the lower limbs. At the core of such alterations is the deterioration of the vascular and neurological networks responsible for procuring systemic thermoregulation. It is within this context that IR imaging is introduced as a likely aiding tool to assist with the clinical diagnosis of DM2 at stages early enough to prevent the evolution of the DFD.
METHODS: IR images of lower limbs are acquired from a cohort of individuals clinically diagnosed with and without DM2. Additional inclusion criteria for patients are to be free from any visible wound or tissue-related trauma (e.g., injuries, edema, and so forth), and also free from non-metabolic comorbidities. All images and data are equally processed and analyzed using indices that evaluate the spatial and temporal evolution of temperature distribution in lower limbs. We studied the temporal response of individuals\' legs after inducing an external stimulus. For this purpose, we combine the information of the asymmetry and thermal response index (ATR) and the thermal response index (TRI), computed using images at different times, improving the results previously obtained individually with ATR and TRI.
RESULTS: A novel representation of the information extracted from IR images of the lower limbs in individuals with and without DM2 is presented. This representation was built using the ATR and TRI indices for the anterior and posterior views (PVs), individually and combining the information from both views. In all cases, the information of each index and each view presents linearity properties that allow said information to be interpreted quantitatively in a well-defined and limited space. This representation, built in a polar coordinate space, allows obtaining sensitivity values of 86%, 97%, and 97%, and specificity values of 83%, 72%, and 78% for the anterior view (AV), the PV, and the combined views, respectively. Additionally, it was observed that the angular variable that defines this new representation space allows to significantly (p < 0.01) differentiate the groups, while correlating with clinical variables of interest, such as glucose and glycated hemoglobin.
CONCLUSIONS: The linearity properties that exist between the ATR and TRI indices allow a quantitative interpretation of the information extracted from IR images of the lower extremities of individuals with and without DM2, and allow the construction of a representation space that eliminates possible ambiguities in the interpretation, while simplifying it, making it accessible for clinical use.