The concept of deep tissue injury under intact skin helps us understand the pathogenesis of pressure ulcers, but the best method for detecting and evaluating deep tissue injury remains to be established. Intermediate-frequency (10-MHz) ultrasonography was performed to evaluate deep tissue injury. The authors analyzed 12 patients (nine male patients and three female patients aged 16 to 92 years) who showed deep tissue injury-related abnormal findings on ultrasonography at the first examination and were followed up until the pressure ulcer reached a final stage. The stage of ulcer worsened in six of 12 cases compared with baseline, and healed in the remaining six patients. The authors recognized four types of abnormal signs unique to deep tissue damage in ultrasonography: unclear layered structure, hypoechoic lesion, discontinuous fascia, and heterogeneous hypoechoic area. Unclear layered structure, hypoechoic lesion, discontinuous fascia, and heterogeneous hypoechoic area were detected at the first examination in 12, 10, seven, and five patients, respectively. Unclear layered structure and hypoechoic lesion were more commonly seen in pressure ulcers in deep tissue injury than the other features, but the follow-up study suggested that discontinuous fascia and heterogeneous hypoechoic area are more reliable predictors of future progression of pressure ulcers. The use of intermediate-frequency ultrasound reliably identified deep tissue injury and was believed to contribute to prevention and treatment of pressure-related ulcers. The results suggest that specific ultrasonographic characteristics may predict which pressure ulcers will progress.

Objective: To investigate whether thermography can be used to detect latent inflammation in pressure ulcers and predict pressure ulcer prognosis in a clinical setting. Method: For this cohort study, we recruited 35 patients with stage II–IV pressure ulcers on the torso, who underwent thermographic assessment on discovery of their pressure ulcer. The patients were followed up for at least 3 weeks. Thermography was performed immediately after dressing removal. Pressure ulcers were classified into two groups depending on whether or not the wound site temperature was lower or higher than the periwound skin: the low temperature group and the high temperature group respectively. A generalised estimation equation was used to estimate the relative risk of delayed healing of pressure ulcers, comparing wounds with high temperatures and low temperatures. Results: Of the 35 patients, 21 had ‘low temperature’ wounds and 14 had ‘high temperature’ wounds at baseline. Two patients in the high temperature group presented with overt infection, and were excluded from further analysis. Twenty-two pressure ulcers were considered to heal ‘normally’ (that is, the wound area reduced by 30% or more within 3 weeks) and 16 did not heal. The baseline DESIGN score (a measure of gross wound status) did not differ in any subscales between the high and low temperature groups. The relative risk for delayed healing in high temperature cases was 2.25 (95% confidence intervals; 1.13–4.47, p=0.021). Sensitivity was 0.56, specificity was 0.82, positive predictive value was 0.75, and negative predictive value was 0.67. Conclusion: Our results indicate that using thermography to classify pressure ulcers according to temperature could be a useful predictor of healing at 3 weeks, even though wound appearances may not differ at the point of thermographical assessment. The higher temperature in the wound site, when compared with periwound skin, may imply the presence of critical colonisation, or other factors which disturb the wound healing. Conflict of interest: None.

Objective: To verify the reliability and validity of FLIR ONE, a device connected to a smartphone, for the assessment of inflammation based on relative temperature increase compared with the thermography routinely used in pressure ulcer (PU) and diabetic foot assessment. Method: Participants in this pilot cross-sectional observational study were recruited from the patients in the PU team rounds and the diabetic foot outpatient clinic at the university hospital in January 2015. Cohen's kappa coefficient with its 95% confidence intervals was used to evaluate the criterion-related validity and inter- and intra-rater reliability for the thermal imaging assessment. For assessing criterion-related validity, a hand-held high-end infrared thermography device was used to provide reference data. Comparison of thermal images between the smartphone-connected device and the hand-held device was performed with both a ‘predetermined range’ and an ‘automatically-set range.’ For assessing inter-rater reliability, two assessors evaluated the thermal images taken by the mobile thermography. For assessing intra-rater reliability, one assessor evaluated the thermal images twice. The thermal images were shown to the assessors at random. Results: Among 16 thermal images obtained from eight patients, kappa coefficients for each value were as follows: for the predetermined range and automatically-set range, respectively, the criterion-related validity was 1.00 (95% confidence interval 1.00–1.00) and 1.00 (95% confidence interval 1.00–1.00); the inter-rater reliability was 1.00 (95% confidence interval 1.00–1.00) and 1.00 (95% confidence interval 1.00–1.00); and the intra-rater reliability was 1.00 (95% confidence interval 1.00–1.00) and 1.00 (95% confidence interval 1.00–1.00). Conclusion: This pilot study suggests that FLIR ONE can work as an alternative device for assessing subclinical inflammation in PUs and the diabetic foot in clinical settings. Our results may facilitate clinicians in accepting the routine use of thermal imaging assessment at the patients' bedside.