# Infrared Thermal Imaging Analysis in Screening for Toddler's Fracture: A Proof-of-Concept Study
## 4 Discussion  
This study indicated that infrared thermal imaging has potential for screening for toddler's fractures on the index ED visit; however, suitable data processing and analysis are required to ensure that the images are suitably analysed and interpreted. Its finding is in line with earlier work that utilised infrared thermal imaging to screen or detect bone fractures [6; 10; 12; 13; 14; 15; 30]. Infrared thermal imaging can be performed quickly, without the need for extensive training. It is harmless, non-contact, and highly cost effective. If the diagnosis of a toddler's fracture cannot be confirmed following an X-ray radiograph, the injured leg is placed in a cast and the leg is X-rayed again after about 10 days. In cases where the leg is not fractured, the child is unnecessarily inconvenienced by the cast and by exposure to X-ray radiation. There is also the cost implication of unnecessary casting, revisits, and repeat X-rays. This was a proof-of-concept study, given the number of participants included; therefore, a larger study will be required to provide greater confidence in infrared thermal imaging as a routine clinical tool in ED environments. The temperature of the injured area changes with time, initially increasing, reaching a peak, and then gradually decreasing. The time since injury (i.e., the time between the occurrence of the injury and the patient attending the hospital) varied for the participants. As this measure was not included in the analysis, it may have negatively affected the results and, thus, requires further exploration; however, all children were imaged within 72 h of the injury. Similarly, some participants had taken medication (analgesics with antipyretic properties) and, thus, the possible effect of the medication on the results needs to be considered. An important issue is the severity of the injury, either resulting in a fracture or not fracture. This was not considered in this study but may have negatively affected the results. This study used a 10-s video recording; however, in future work, an exploration will be carried out to establish whether a single image could be sufficient. The scatter plots of Figures 4, 7 and 8 indicated that a few participants were not grouped correctly in accordance with their injury diagnosis. Further investigation of image processing and feature extraction techniques may help to improve the differentiation. In this study, given the number of participants, a pattern recognition approach was not used to differentiate between participants with and without a fracture. In follow-on studies, \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Principal**} & \multicolumn{2}{c}{**Probability**} \\ \cline{2-3}  & **Shapiro-Wilk Test** & **\(t\)-Test** \\ \hline
**PC1** & **0.417** & **0.0485** \\
**PC2** & 0.424 & 0.2005 \\
**PC3** & 0.122 & 0.2420 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Statistical tests for the three main principal components. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Principal Component**} & \multicolumn{2}{c}{**Mean**} & \multicolumn{2}{c}{**Standard Deviation**} \\ \cline{2-5}  & **Fracture** & **Not Fracture** & **Fracture** & **Not Fracture** \\ \hline PC1 & 0.665 & \(-\)0.355 & 0.797 & 1.240 \\ PC2 & \(-\)0.263 & 0.140 & 0.835 & 0.615 \\ PC3 & 0.130 & \(-\)0.070 & 0.275 & 0.421 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Mean and standard deviation values for the main three principal components for participants with and without a fracture. this would be considered. Artificial intelligence methods relevant to ED practice [31; 32; 33] will also be explored in more detail. This study included infrared thermal images taken from the front of the leg. During the follow-on study, infrared thermal images recorded from the sides of the legs will be combined with the image recorded from the front of the leg to explore further improvement of the results. This study's findings were promising and justify the need for a larger study.