High resolution thermal imaging (HRTI) imaging is based on recording and processing of a part
of electromagnetic spectrum below visible light i.e. infrared (IR) band. Objects with a
temperature above -273 °C (-459.7 °F) emit IR (i.e. thermal) radiation. In HRTI a highly
sensitive thermal camera that operates to the mid (3-5 μm) and long (7-14 μm) IR bands of the
electromagnetic spectrum is used for imaging. The method results in a series of images
(capture rate typically 30 frames per second). The images are processed using specialised
software to extract and interpret its information. This includes neural networks and similar
artificial intelligence models.
Detection of an injury using thermal imaging relies on underlying physiology of temperature
differentials. Dermal temperature differentials usually do not exceed 0.25°C, while
differentials in excess of 0.65 °C are consistently related to pathology. Therefore
observation of a significant temperature differential can be an indication of an injury. The
use of infrared HRTI in paediatric for musculoskeletal diagnosis and monitoring as well as
physiological measurements have showed potential. Examples of the related studies are:
Vertebral fractures were detected in osteogenesis imperfecta patients using thermal
imaging .
Thermal imaging assisted in diagnosis of limp, including bone fracture cases
Thermal imaging showed potential for differentiating between wrist fracture and sprain.
Thermal imaging could accurately quantify the temperature difference between inflamed
and uninflamed knees thus assisting with the diagnosis of juvenile idiopathic arthritis.
Infrared thermal imaging has proved valuable in detecting inflammatory intra-abdominal
pathology in infants.
Thermal imaging provided effective for measuring respiration rate in a non- contact
manner, i.e. no sensing unit attached to the patient's body.
Blood convection warms the skin by transfer of heat from the core and this process plays the
major role in determining skin temperature. Skin's has a thermoregulatory role, i.e. it
generates, absorbs, conducts and radiates heat. Changes in the skin surface temperature are
valuable in detecting physiological and pathological states such as inflammation.
With recent developments in thermal imaging devices, the use of infrared imaging for injury
examination is expanding, with more evidence supporting its use. However, the data in
children are still limited, with the investigators' research group undertaking significant
development work in this field.
In this study the IR emission (characterised by heat radiation) from the skin at the site of
injury is imaged and analysed to screen for a toddler's fracture. The hypothesis is that the
inflammation and blood perfusion in fracture and less severe injuries at the site of injury
are distinct, leading to distinct temperature gradients.
Toddler's fracture is characterised as a non-displaced spiral fracture of the tibial shaft in
young children, usually between the ages of 9 months to 3 years. However other lower
extremity injuries in young children can also have similar clinical appearance to the
non-displaced spiral tibial fracture. Toddler's fracture usually results from an indirect
innocuous twisting or rotational force applied to the foot and lower leg. The cause could be
a stumble or fall or attempts to extricate the foot from between the bars of a crib for
example.
Innovations in the use of HRTI in screening toddler's fracture can be beneficial as this
could reduce the number of unnecessary x-ray radiographs by filtering out cases where the
bone is not fractured. Given that toddler's fracture may not be visible on the radiograph
close to the time of the injury's occurrence and a repeat radiograph around 10 days is
usually required, earlier identification of a fracture would be beneficial. HRTI may be able
to detect a fracture at the index visit, thus allowing directed management.