Infrared thermography is useful for ruling out fractures in paediatric emergencies

Uses of infrared thermography in acute illness: a systematic review

Introduction

Infrared thermography (IRT) is a non-contact, non-ionising imaging modality, providing a visual representation of temperature distribution across a surface.

Methods

We conducted a systematic search of indexed and grey literature for studies investigating IRT applications involving patients in acute care settings. Studies were categorised and described along themes identified iteratively using narrative synthesis. Quality appraisal of included studies was performed using the Quality Assessment tool for Diagnostic Accuracy Studies.

Results

Of 1,060 unique records, 30 studies were included. These were conducted in emergency departments and intensive care units involving adult, paediatric and neonatal patients. IRT was studied for the diagnosis, monitoring or risk stratification of a wide range of individual conditions. IRT was predominantly used to display thermal change associated with localised inflammation or microcirculatory dysfunction. Existing research is largely at an early developmental stage.

Discussion

We recommend that high quality diagnostic validation studies are now required for some clinical applications. IRT has the potential to be a valuable tool in the acute care setting and represents an important area for future research particularly when combined with advances in machine learning technology.

Systematic review registration

CRD 42022327619 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=327619).

Convolutional Neural Network to Classify Infrared Thermal Images of Fractured Wrists in Pediatrics

Convolutional neural network (CNN) models were devised and evaluated to classify infrared thermal (IRT) images of pediatric wrist fractures. The images were recorded from 19 participants with a wrist fracture and 21 without a fracture (sprain). The injury diagnosis was by X-ray radiography. For each participant, 299 IRT images of their wrists were recorded. These generated 11,960 images (40 participants × 299 images). For each image, the wrist region of interest (ROI) was selected and fast Fourier transformed (FFT) to obtain a magnitude frequency spectrum. The spectrum was resized to 100 × 100 pixels from its center as this region represented the main frequency components. Image augmentations of rotation, translation and shearing were applied to the 11,960 magnitude frequency spectra to assist with the CNN generalization during training. The CNN had 34 layers associated with convolution, batch normalization, rectified linear unit, maximum pooling and SoftMax and classification. The ratio of images for the training and test was 70:30, respectively. The effects of augmentation and dropout on CNN performance were explored. Wrist fracture identification sensitivity and accuracy of 88% and 76%, respectively, were achieved. The CNN model was able to identify wrist fractures; however, a larger sample size would improve accuracy.

Infrared Thermography-A Novel Tool for Monitoring Fracture Healing: A Critically Appraised Topic With Evidence-Based Recommendations for Clinical Practice

CLINICAL SCENARIO

Stress fractures are one of the most common injuries in athletes. Unfortunately, they are hard to diagnose, require multiple radiology exams and follow-up which leads to more exposure to radiation and an increase in cost. Stress fractures that are mismanaged can lead to serious complications and poorer outcomes for the athlete. During the rehabilitation process, it would be beneficial to be able to monitor the healing of fractures to know when it is safe to gradually allow a patient to a return to sport because the return to activity is not usually objective and based on pain level.

CLINICAL QUESTION

Can infrared thermography (IRT) be a useful tool to measure the pathophysiological state of the fracture healing? The aim of this critically appraised topic is to analyze the current evidence of IRT for measuring the temperature change in fractures to provide recommendations for medical practitioners.

SUMMARY OF KEY FINDINGS

For this critically appraised topic, we examined 3 articles that compared medical imaging and IRT over multiple time points during the follow-up. The 3 articles concluded that a 1 °C asymmetry in temperature followed by a return to normal (less than 0.3 °C) temperature during the healing process of fractures can be monitored using IRT.

CLINICAL BOTTOM LINE

Once the patient has been diagnosed with a fracture, IRT can safely be used to monitor the evolution of a fracture. When the thermogram progresses from a hot thermogram to a cold thermogram, the healing is considered good enough to return to sport.

STRENGTH OF RECOMMENDATION

Grade 2 evidence exists to support IRT being used by clinicians to monitor fracture healing. Due to the limited research and novelty of the technology, the current recommendations are for following the treatment of the fracture once the initial diagnosis is made.

Detecting bone lesions in the emergency room with medical infrared thermography

Introduction

Low- to high-energy impact trauma may cause from small fissures up to extended bone losses, which can be classified as closed or opened injuries (when they are visible at a naked eye).

Objective

The aim of this study was to investigate the feasibility of clinical diagnosis of bone trauma through medical infrared thermography, in a hospital emergency room.

Methods

Forty-five patients with suspected diagnosis of bone fracture were evaluated by means of medical infrared images, and the data correlated with the gold standard radiographic images, in the anteroposterior, lateral, and oblique views, at the orthopedic emergency department. The control group consisted of thermal images of the contralateral reference limb of the volunteers themselves. Data were acquired with a medical grade infrared camera in the regions of interest (ROIs) of leg, hand, forearm, clavicle, foot, and ankle.

Results

In all patients evaluated with a diagnosis of bone fracture, the mean temperature of the affected limb showed a positive difference greater than 0.9 °C (towards the contralateral), indicating the exact location of the bone trauma according, while the areas diagnosed with reduced blood supply, showed a mean temperature with a negative variation.

Conclusion

Clinical evaluation using infrared imaging indicates a high applicability potential as a tool to support quick diagnosis of bone fractures in patients with acute orthopedic trauma in an emergency medical setting. The thermal results showed important physiological data related to vascularization of the bone fracture and areas adjacent to the trauma well correlated to radiographic examinations.

Thermography as a non-ionizing quantitative tool for diagnosing periapical inflammatory lesions

Background

Thermography is a contemporary imaging modality based on acquiring and analyzing thermal data using non-contact devices. The aim of the present study was to assess the validity of thermography, compared with that of the reference-standard, for the diagnosis of periapical inflammatory lesions and to evaluate the temperature ranges for acute pulpitis with apical periodontitis (AAP), acute periapical abscess (AA) and chronic periapical abscess (CA).

Methods

AAP, AA and CA were diagnosed based on clinical and radiographic criteria. Thermographic data were acquired using the FLIR E-5 Infrared Camera. Extraoral thermal images were taken from the front and right and left sides of patients whose mouths were closed, and one intraoral thermal image was taken from the palatal perspective. Agreement in the diagnoses based on the combination of clinical and radiographic assessments and the thermographic evaluation was calculated. The temperature ranges of the three diagnostic subgroups were also measured.

Results

A total of 80 patients were enrolled in this study. The mean intraoral thermal image temperature for AA was 37.26 ± 0.36, that for CA was 35.03 ± 0.63 and that for AAP was 36.07 ± 0.45. The differences between the mean intraoral thermal temperatures of the three diagnostic groups were statistically significant (P < 0.001). The result of the Kappa coefficient of agreement between the combination of clinical and radiographic assessments and the thermographic evaluation was significant (P < 0.001).

Conclusions

Thermography is an effective, quantitative and nonionizing approach that can be used for the diagnosis of periapical inflammatory lesions. The results of the present study indicated that the highest thermal image temperatures were recorded for AA. Thermography might be able to detect inflammatory reactions during the preclinical stage, leading to early diagnosis.

Infrared thermography in the diagnosis of musculoskeletal injuries: A protocol for a systematic review and meta-analysis

BACKGROUND

Musculoskeletal injuries (MSDs) have become a major public health problem worldwide. Current diagnosis techniques for MSDs are often associated with radiation exposure, expensive cost, or contraindication. Infrared thermography (IRT) is becoming a proposed tool to assist in diagnosing MSDs, but current evidence is inconclusive. Thus, herein we aimed to evaluate the diagnostic accuracy of IRT for MSDs.

METHODS

We will search EMBASE, MEDLINE, EBSCO, Cochrane Library, SCOPUS, Web of Science, CNKI, SinoMed, and Wangfang. Two researchers will independently screen eligible studies. Study quality will be evaluated based on the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Data synthesis will be completed using STATA 14.0 software. A bivariate random-effects analysis will be utilized to estimate the pooled estimation of the diagnostic odds ratio (DOR) and the summary receiver operating characteristics (SROC) curve. Subgroup analyses will be performed to determine heterogeneity sources.

RESULTS

This systematic review and meta-analysis will provide reliable evidence about the diagnostic accuracy of IRT for MSDs.

CONCLUSION

The conclusion of this study will be published in a peer-reviewed journal.

ETHICS AND COMMUNICATION

Given that this is a systematic review of published research, patient consent and ethical approval are not relevant. The findings of this study will be disseminated through conference presentations and publication in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42020184867.

Thermographic camera in traumatology, diabetic foot and reconstructive procedures

Traumatic lacerations, burns and ulcerations are a common cause of admission in the plastic surgery wards. Clinical evaluation alone sometimes provides insufficient or even inaccurate information. Thermographic camera is a new tool that could provide additional information regarding skin vascularization, presence of inflammation or involvement of deep tissue. A prospective study was realized for assessing pre and postoperative status of patients with lacerations, trauma, burn and diabetic foot. Preoperative evaluation helped in assessing bone involvement, inflammation and infection in order to decide the necessity of surgery. Postoperative evaluation was useful in preventing and lowering the rate of complications. Thermographic camera could be a new helpful and non-invasive tool especially in emergency hospitals in order to assess rapidly and objectively wound status and to start if necessary, a surgical treatment.

Evaluation of infrared technology to detect category I and suspected deep tissue injury in hospitalised patients

OBJECTIVE

To evaluate the use of an infrared thermography device in assessing skin temperature among category I pressure ulcer (PU) and/or suspected deep tissue injuries (SDTI) with intact skin.

METHODS

An observational cross-sectional study design was used. Adult inpatients (cases) who had a category I PU or suspected deep tissue injury (skin intact) on the sacral or heel during the study period (March to April 2018) were recruited. Patients without a PU were also recruited to act as control. Thermal images of the patient's PU site and non-PU site were taken within 24 hours of PU occurrence. Thermal images of the control patients (no PU) were also taken. Each PU case was matched to three control patients in terms of age, gender, race and anatomical sites. All thermal images were taken using a portable CAT S60 Thermal Imaging Rugged Smartphone (Caterpillar Inc., US) that provided readings of the skin temperature in degrees Celsius.

RESULTS

A total of 17 cases and 51 controls were recruited. Among the cases, the mean difference in skin temperature between the PU site (mean: 31.14°C; standard deviation [SD]: 1.54) and control site within the cases (mean: 28.93°C; SD: 3.47) was significant (difference: 2.21±3.66°C; p=0·024). When comparing between all cases and controls, the mean temperature difference was non-significant. When comparing between the category I PU and suspected deep pressure injury cases, the mean difference was also non-significant.

CONCLUSION

Using infrared thermography technology at the bedside to measure skin temperature will support the clinical diagnosis of patients with skin types I to III. However, there is a need for a more accurate and objective measurement to identify and diagnose early category I PU or suspected deep tissue injury in adult patients with darker skin types 4 and above, enabling early initiation of preventive measures in the hospital acute care setting.

Infrared thermal imaging as a screening tool for paediatric wrist fractures

Wrist injuries are common in paediatric trauma; however, only half of children evaluated with an x-ray for possible fractures will have one. Thermal imaging offers a possible non-ionising method of screening for fractures and thus reducing negative x-ray rates. One hundred five children attending the Emergency Department for wrist injuries were recruited. Two 30-s thermal videos were recorded from injured and uninjured wrists-in flat and 45° elevated positions. A region of interest (ROI) was defined on each wrist. Cases in which the ROI was covered or had ice applied were excluded, leaving 40 patients for analysis. Comparisons of ROI included (i) injured and uninjured wrists-flat and elevated positions; (ii) as in (i) with a reference region on the proximal forearm subtracted; (iii) injured wrist ROI-flat and elevated positions. Fractures and sprains increased the mean skin surface temperature by 1.519% (p = 0.008) and 0.971% (p = 0.055) respectively compared with the uninjured wrist. The mean temperature difference between flat and elevated positions for fractures was 0.268% and - 0.1291% for sprains. This difference was statistically significant for fracture (p = 0.004) but not sprain (p = 0.500). The temperature differences recorded by thermal imaging between fractured and sprained wrists may assist in differentiation of these injuries. Graphical abstract Operational stages involved from thermal video recording to generation of results.

Development of a high-resolution infrared thermographic imaging method as a diagnostic tool for acute undifferentiated limp in young children

Acute limp is a common presenting condition in the paediatric emergency department. There are a number of causes of acute limp that include traumatic injury, infection and malignancy. These causes in young children are not easily distinguished. In this pilot study, an infrared thermographic imaging technique to diagnose acute undifferentiated limp in young children was developed. Following required ethics approval, 30 children (mean age = 5.2 years, standard deviation = 3.3 years) were recruited. The exposed lower limbs of participants were imaged using a high-resolution thermal camera. Using predefined regions of interest (ROI), any skin surface temperature difference between the healthy and affected legs was statistically analysed, with the aim of identifying limp. In all examined ROIs, the median skin surface temperature for the affected limb was higher than that of the healthy limb. The small sample size recruited for each group, however, meant that the statistical tests of significant difference need to be interpreted in this context. Thermal imaging showed potential in helping with the diagnosis of acute limp in children. Repeating a similar study with a larger sample size will be beneficial to establish reproducibility of the results. Graphical abstract A young child with an acute undifferentiated limp undergoes thermal imaging and the follow on image analysis assists the limp diagnosis.

Evaluation of high resolution thermal imaging to determine the effect of vertebral fractures on associated skin surface temperature in children with osteogenesis imperfecta

Vertebral fractures are common in children with osteogenesis imperfecta (OI). Current imaging methods for fracture detection (X-ray and DXA) use ionising radiation. This pilot study explored whether the alteration in blood flow in vertebral fractures results in skin temperature changes that may be detected using high resolution thermal imaging (HRTI) and thus assist diagnosis and monitoring of fractures in OI patients. Eleven participants aged 5-18 years with OI and known vertebral fractures were enrolled. Small metal discs were placed on the skin surface alongside the vertebrae before participants had DXA and X-ray scans and thermal imaging of their backs. Visibility of the discs on the DXA and X-ray scans and thermal images allowed the temperatures of the skin surface above vertebrae without (healthy) and with fractures to be compared to their respective adjacent skin surface regions (region of reference, ROR) by calculating the temperature percentage change (TPC). The TPC between the skin temperature over the fractured thoracic vertebrae (n = 11) and the ROR was significant (1.44%, p = 0.002, 95% confidence). TPC between the skin temperature over healthy thoracic vertebrae and ROR was not significant (0.97%, p = 0.15, 95% confidence). HRTI may provide a novel tool for assisting in detection of vertebral fractures in OI. Graphical abstract • Patients (aged 5-18) with osteogenesis imperfecta and known vertebral fractures. • Thermal imaging was performed alongside routine imaging (DXA scan and spinal X-ray). • The temperature above each vertebra was compared with its adjacent skin region to assist with diagnosis of the fracture.

Infrared thermography in paediatrics: a narrative review of clinical use

BACKGROUND

Infrared thermography (IRT) has been used in adult medicine for decades, but recent improvements in quality of imaging and increasing computer processing power have allowed for a diversification of clinical applications. The specific usage of IRT in a paediatric population has not been widely explored, so this article aims to summarise the available literature in this area. IRT involves the non-contact, accurate measurement of skin surface temperature to identify temperature changes suggesting disease. IRT could well have unique applications in paediatric medicine.

METHODS

Electronic searches were performed independently by two authors, using the databases of MEDLINE (via Web of Science), the Cochrane Library, CINAHL (EBSCO) and Scopus, including articles published from 1990 to July 2016. The search strategy that was used aimed to include articles that covered the topics of IRT and children, including studies with participants 18 years old or younger. Articles were screened by title and abstract by two authors. Meta-analysis was not performed due to the marked heterogeneity in applications, study design and outcomes: this is a narrative summary of the available literature.

RESULTS

IRT has been shown to be an effective additional diagnostic tool in a number of different paediatric specialties, namely in fracture screening, burns assessment and neonatal monitoring. Small measurable skin temperature changes can effectively add to the clinical picture, while computer-tracking systems can be reliably used to focus investigations on particular areas of the body.

CONCLUSION

Throughout this review of the available literature, there has been a general consensus that this non-invasive, non-irradiating and relatively inexpensive technology may well have a place in the management of paediatric patients in the future.

Determining peripheral skin temperature: subjective versus objective measurements

AIM

Diseases that affect peripheral vasculature or neurological function can manifest with peripheral skin temperature abnormalities. This pilot study investigates the accuracy of current physical examination techniques and determines whether a hand-held infrared device can be used to estimate peripheral skin temperature and detect temperature disparities.

METHODS

Comparison between traditional physical examination of hands/feet by 30 healthcare professionals and a hand-held infrared device was made in 12 individuals (ages 4-25 years; 5 with disorders affecting peripheral skin temperature). Thermal camera measurements served as the reference temperature for comparison.

RESULTS

A total of 231 extremity examinations by healthcare professionals were analysed. Healthcare professionals correctly identified subjects with colder or warmer than normal peripheral temperature. Hand-held device measurements were significantly different than reference measurements, with the size of the temperature difference diverging significantly between hands (1.20°C) and feet (0.78°C). When analysing temperature disparities, healthcare professionals identified fewer clinically significant disparities (≥3.0°C) than the hand-held device (76% vs. 99%).

CONCLUSION

Although different from reference temperatures, the hand-held infrared device provided a more accurate and objective method than traditional physical exam in identifying peripheral skin temperature asymmetries that may be related to chronic paediatric illness.

Infrared thermographic assessment of changes in skin temperature during hypoglycaemia in patients with type 1 diabetes

AIMS/HYPOTHESIS

Hypoglycaemia is associated with reduced skin temperature (Ts). We studied whether infrared thermography can detect Ts changes during hypoglycaemia in patients with type 1 diabetes and how the Ts response differs between patients with normal hypoglycaemia awareness and hypoglycaemia unawareness.

METHODS

Twenty-four patients with type 1 diabetes (ten aware, 14 unaware) were studied during normoglycaemia (5.0-6.0 mmol/l), hypoglycaemia (2.0-2.5 mmol/l) and during recovery from hypoglycaemia (5.0-6.0 mmol/l) using hyperinsulinaemic glucose clamping. During each 1 h phase, Ts was measured twice by infrared thermography imaging in pre-defined areas (nose, glabella and the five left fingertips), symptoms of hypoglycaemia were scored and blood was sampled.

RESULTS

Ts decreased during hypoglycaemia on the nose and glabella. The highest decrements were recorded on the nose (aware: -2.6 °C, unaware: -1.1 °C). In aware patients, the differences in temperature were statistically significant on both nose and glabella, whereas there was only a trend in the unaware group. There was a significant difference in hypoglycaemia-induced temperature changes between the groups. Patients in the aware group had higher hypoglycaemia symptom scores and higher adrenaline (epinephrine) levels during hypoglycaemia.

CONCLUSIONS/INTERPRETATION

The hypoglycaemia-associated decrement in Ts can be assessed by infrared thermography and is larger in patients with normal hypoglycaemia awareness compared with unaware patients.