Infrared thermal imaging in medicine.

This review describes the features of modern infrared imaging technology and the standardization protocols for thermal imaging in medicine. The technique essentially uses naturally emitted infrared radiation from the skin surface. Recent studies have investigated the influence of equipment and the methods of image recording. The credibility and acceptance of thermal imaging in medicine is subject to critical use of the technology and proper understanding of thermal physiology. Finally, we review established and evolving medical applications for thermal imaging, including inflammatory diseases, complex regional pain syndrome and Raynaud's phenomenon. Recent interest in the potential applications for fever screening is described, and some other areas of medicine where some research papers have included thermal imaging as an assessment modality. In certain applications thermal imaging is shown to provide objective measurement of temperature changes that are clinically significant.

New standards for devices used for the measurement of human body temperature.

Significant changes in recording of human body temperature have been taking place worldwide in recent years. The clinical thermometer introduced in the mid-19th century by Wunderlich has been replaced by digital thermometers or radiometer devices for recording tympanic membrane temperature. More recently the use of infrared thermal imaging for fever screening has become more widespread following the SARS infection, and particularly during the pandemic H1N1 outbreak. Important new standards that have now reached international acceptance will affect clinical and fever screening applications. This paper draws attention to these new standard documents. They are designed to improve the standardization of both performance and practical use of these key techniques in clinical medicine, especially necessary in a pandemic influenza situation.

The historical development of thermometry and thermal imaging in medicine.

Human body temperature has been an important part of medicine since very early times. However, until the thermometer was developed in the 16th century measurement was not possible. Some 200 years later, Wunderlich laid the foundation for clinical thermometry, and temperature charts became commonplace throughout the world. More recently thermal imaging has broadened the understanding of body surface temperature in health and disease. Standards for computer-assisted infrared imaging are well developed, and present-day fast high-resolution imaging is less expensive and more reliable than it was 40 years ago.

A comparison of bone loss in early and late rheumatoid arthritis using quantitative phalangeal ultrasound.

This study compares amplitude-dependent speed of sound (AD-SoS) measured by phalangeal ultrasonography in a group of 60 patients with early rheumatoid arthritis (RA) with those who had had the disease for more than 4 years. The mean duration of the early disease group was 1.4 years, and the mean of the established RA group was 14.6 years. Plasma viscosity (PV), C-reactive protein (CRP) and HAQ scores were obtained. Forty-nine patients with early RA had hand radiographs assessed by the Larsen score method. The DBM Sonic system was assessed on normal volunteers and a coefficient of variation of 0.88% obtained. A significant correlation was found between the left and right hands of the patients groups studied ( r=0.84). The mean Z score of both hands was therefore used in comparing the two clinical groups. Results showed no correlation between CRP, PV and Z scores of AD-SoS. The HAQ scores showed a weak negative correlation, and there was no correlation between the Larsen score and Z score, or the number of swollen joints and Z score. However, the early and established groups with RA were significantly different (#E5/E5#=0.004). Within the early RA group the Z score for AD-SoS was lower in those with disease duration of less than 2 years (-1.71) than in those with disease duration of 2-4 years (-1.01). This suggests that bone loss in the fingers is greater in the first 2 years of disease than in the following 2 years, which might reflect an effect of treatment.

A controlled pilot study of the utility of mirror visual feedback in the treatment of complex regional pain syndrome (type 1).

BACKGROUND: We assessed mirror visual feedback (MVF) to test the hypothesis that incongruence between motor output and sensory input produces complex regional pain syndrome (CRPS) (type 1) pain. METHODS: Eight subjects (disease duration > or =3 weeks to < or =3 yr) were studied over 6 weeks with assessments including two controls (no device and viewing a non-reflective surface) and the intervention (MVF). Pain severity and vasomotor changes were recorded. RESULTS: The control stages had no analgesic effect. MVF in early CRPS (< or =8 weeks) had an immediate analgesic effect and in intermediate disease (< or =1 yr) led to a reduction in stiffness. At 6 weeks, normalization of function and thermal differences had occurred (early and intermediate disease). No change was found in chronic CRPS. CONCLUSIONS: In early CRPS (type 1), visual input from a moving, unaffected limb re-establishes the pain-free relationship between sensory feedback and motor execution. Trophic changes and a less plastic neural pathway preclude this in chronic disease.