Which is the preferred image modality for paediatricians when assessing photographs of bruises in children?

Images of bruises serve as a clinical record and may facilitate forensic analysis in the assessment of suspected physical child abuse. Currently, only conventional imaging techniques are employed; however, alternative imaging modalities using visible and non-visible light may provide additional information. We sought to determine the image modality preferences of paediatricians and the between-observer agreement therein. Nine paediatricians who work in child protection independently compared five image modalities (conventional colour, conventional grey-scale, cross-Polarised, ultraviolet, and infrared) of four bruises, with a compliance rate of 95%. All images were taken using a standardised set of protocols with Nikon D90 cameras and 105-mm macro-lenses. The paediatricians almost unanimously chose cross-Polarised as their preferred modality for all four bruises when assessing boundary, shape, colour, size, and absence of light reflectance. Conventional colour and grey-scale imaging were typically ranked second and third. Ultraviolet and infrared were consistently ranked in the least two favourable positions. Between-observer agreement on ranking order was high, with coefficients of concordance ranging from 0.76 to 0.96. Combinations of imaging modalities chosen to give the most complete picture of the bruise predominantly consisted of cross-Polarised and conventional (colour and grey-scale). This pilot study demonstrated that clinicians collectively favoured cross-Polarised in addition to conventional imaging. Further studies are required to determine the value of ultraviolet and infrared imaging in the assessment of childhood bruises.