Heat distribution over normal and abnormal joints: thermal pattern and quantification.

Abstract

SUMMARY We have identified regular thermal patterns over normal knee, ankle, and elbow joints and demonstrate how synovitis affecting these joints may be identified by alteration or loss of the thermal pattern. Sixty healthy volunteers were thermographed on a total of 190 occasions, and 614 out of 618 joints conformed to the normal thermal pattern. Eight-five patients with synovitis of at least one of the specified joints were thermographed on a total of 339 occasions, and 322 out of 1362 thermograms were abnormal. No joint with clinical evidence of synovitis had a normal thermal pattern. As temperature-based parameters have been found to show marked diumal variation and relative frequency distributions do not have this drawback, we suggest that quantification of synovitis by thermography should in future be based on abnormalities of thermal pattern rather than absolute skin temperature values.The objective assessment of disease activity in rheumatoid arthritis is difficult. Many parameters are based on patients' symptoms, which may not give an accurate indication of the progress of the disease, and laboratory evaluation can be unhelpful.' Infrared thermography (IRT) has been used for the past 10 years to measure skin temperature over inflamed joints.23 Horvath and Hollander4 measured the intra-articular temperature in patients with rheumatoid arthritis and noted that it could be used as a guide to the acuteness of inflammation. Bacon et al. 5showed that measurement of mean skin temperature could be used as a measure of disease activity. Skin temperature is affected by many internal and external factors.6 Circadian rhythm, metabolic rate, calorific intake, physical activity, emotional state, and atmospheric temperature and humidity can all exert a marked effect on skin temperature. In particular, owing to the proximity of blood vessels to the skin in the extremities even small alterations in vascular tone will produce large changes in skin temperature.Many of these factors are uncontrollable. In addition, the variation leads to difficulties in standardisation and relating a single measurement to an arbitrary 'normal' temperature.7We therefore set out to examine whether such relation to absolute arbitrary standards is necessary and whether inspection of the thermogram could identify the presence or absence of synovitis. Thermograms of the knee, elbow, and ankle joints of normal subjects have been compared with those from patients with clinical evidence of synovitis. To test the effect of diurnal variation on the methods of analysis serial readings were obtained at different times of day. Methods and patientsThermography. This was carried out in a draught-free room with ambient temperature controlled to 20 5°C + 0 5°C and humidity 50% + 10%. Subjects were seated in a modified dentist's chair with their limbs exposed and a sleeveless jacket worn.An AGA Thermovision 680 medical system was used to detect infrared emission, and all thermograms were recorded in digital form on magnetic tape for subsequent analysis with...

Utilização da imagem infravermelha em reumatologia

“…Classicamente, há dois índices para avaliação da atividade inflamatória por imagem IR: o índice termográfico (TI), que é a análise multi-isotérmica com base na temperatura cutânea média de uma área articular pré-definida (ROI) (3) , e o índice de distribuição térmica (HDI), com base em ± 1 desvio-padrão (DP) da temperatura cutânea média dessa ROI (31) . Os valores do TI das articulações periféricas normais variam entre 0,35 e 2,30, com uma média de 1,20.…”

“…Salisbury et al avaliaram 85 pacientes com evidência clínica de sinovite em pelo menos uma articulação. De 1.362 termogramas, incluindo articulações sadias, todos os 322 com padrão alterado na distribuição térmica apresentavam sinovite clinicamente (31) . Porém, como ressalta Thumb (44) , nada substitui um experiente reumatologista, uma vez que o diagnóstico da AR é clínico e nenhum exame isolado é diagnóstico.…”

Thermal Imaging as a Noninvasive Diagnostic Tool for Anterior Knee Pain Following Implantation of Artificial Knee Joints

“…It is a picture of autonomic dysfunction which seems to correlate well with regions of pain (Boas, 1964;Salisbury et al, 1983;Spalding et al, 2008). Pain felt at the area of injury is generally seen to be hyperthermic (increased thermal emission) due to decreased sympathetic function and alpha receptor blockage from metabolic by-products such as substance P, kinins, histamines, and so on (Bjorkstrom and Goldie, 1980;Fernandez-Duenas et al, 2010).…”

“…In the field of veterinary medicine, where localization of pain sometimes is not possible, the IR diagnostic system, used in combination with a clinical examination and additional imaging modalities, provides highly effective results by pinpointing areas of suspicion (Brenner et al, 2006;Craciunescu et al, 2009;Infernuso et al, 2010;Kastberger et al, 2003;Poljak-Blazi et al, 2009;Stubsjoen et al, 2009). In human medicine, thermography has already been effectively used for non-invasive assessment of disease activity in osteoarthritis of the knee, hands and the tempomandibular joint (Boas, 1964;Fikackova and Ekberg, 2004;Salisbury et al, 1983;Selfe et al, 2006;Spalding et al, 2008), as well as in rheumatic arthritis (Boas, 1964;Brenner et al, 2006;Salisbury et al, 1983;Spalding et al, 2008), scleroderma, Raynaud´s disease (Chikura et al, 2010;Schlager et al, 2010), frozen shoulder or rotator cuff tendinitis (Vecchio et al, 1992), breast cancer (Arora et al, 2008;EtehadTavakol et al, 2010;Gescheit et al, 2010;Ng, 2009), reflex sympathetic dystrophy (Bruehl et al, 1996;Krumova et al, 2008;Niehof et al, 2008), sexual dysfunction (Seeley et al, 1980;Smith et al, 2009) and for the evaluation of patellofemoral arthralgia (kneecap pain) in athletes (Devereaux et al, 1986). However, in spite of being a reliable method for objective pain evaluation (Friedman, 1994;Han et al, 2010;Leclaire et al, 1996;Niehof et al, 2006;Pawl, 1991;…”

Use of infrared thermography as a tool to monitor skin temperature along the recovery process of an anterior cruciate ligament surgery

“…Binder et al (1983) and Salisbury et al (1983) both demonstrated higher T sk in diurnal assessments when using IRT.…”