Kurt Ammer

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 Raynauds 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.

An Overview of Recent Application of Medical Infrared Thermography in Sports Medicine in Austria

Medical infrared thermography (MIT) is used for analyzing physiological functions related to skin temperature. Technological advances have made MIT a reliable medical measurement tool. This paper provides an overview of MIT’s technical requirements and usefulness in sports medicine, with a special focus on overuse and traumatic knee injuries. Case studies are used to illustrate the clinical applicability and limitations of MIT. It is concluded that MIT is a non-invasive, non-radiating, low cost detection tool which should be applied for pre-scanning athletes in sports medicine.

Standardization of infrared imaging

To provide an atlas and database for the temperature distribution of the skin in normal human subjects aged from 10 years to 75 years. The technique used in digital infrared thermal imaging which has been in use since 1960. Despite, many different applications and published studies, a normal database is not available. It is particularly needed for forensic and hospital clinic use.

Severity of chronic venous disorders and its relationship to the calf muscle pump.

BACKGROUND To investigate the relationship between the calf muscle pump and the clinical severity of chronic venous disorders (CVD) and of venous function parameters. PATIENTS AND METHODS 84 limbs in 44 patients underwent duplex scan and digital photoplethysmography (DPPG), the range of ankle movement was measured by digital goniometry and strength of calf muscles was determined by dynamometry. Limbs were allocated on the basis of clinical signs of CVD (according to the CEAP classification) into 4 groups: controls (no signs and symptoms of CVD): 34 limbs, C1/2: 24 limbs, C3/4: 16 limbs, C6: 10 limbs. RESULTS A higher degree in clinical severity of CVD was related to shorter venous refilltime (VRT) and lower venous pump power (VPP) measured by DPPG. The strength of dorsiflexion was significantly reduced in group C6 compared to controls. There was a positive correlation between measurements of DPPG and the strength of dorsiflexion and also with total strength (p < 0.05). In limbs with pathological reflux (> 1 s) the strength of dorsiflexion, range of ankle plantarflexion movement and total range of ankle movement were significantly reduced compared to those without pathological reflux (p < 0,05). Strength of plantarflexion was significantly reduced in group C1/2 compared to control group (p < 0,05). CONCLUSIONS Strength of dorsiflexion seems to be the main driving factor of normal venous flow and range of ankle movement is impaired in patients with pathological venous reflux. Further prospective studies should clarify if additional strengthening of ankle dorsiflexors should be included in well established venous training programs.

Diagnosis of Raynaud's phenomenon by thermography

Background/aims: The aim was to clarify whether cold fingers before a moderate cold stress test can predict a prolonged delay (more than 20 min) in rewarming, as diagnostic for Raynauds phenomenon.

Double-blind, randomised, placebo controlled low level laser therapy study in patients with primary Raynaud's phenomenon

BACKGROUND No causal treatment of primary Raynauds phenomenon is available due to its unclear aetiology. Low level laser therapy (LLLT) is applied in a multitude of medical conditions often without sufficient evidence of efficacy and established mechanisms. To asses the effect of this therapy in patients with primary Raynauds phenomenon a randomised, double blind, placebo controlled cross over study was designed. PATIENTS AND METHODS Absolute and relative frequency and intensity of vasospastic attacks during three weeks of either LLLT or placebo therapy and results of infrared thermography before onset and at the end of both therapy sequences were evaluated in 15 patients with primary Raynauds phenomenon. RESULTS Frequency of Raynauds attacks was not significantly affected by low level laser therapy. Compared to placebo a significantly lower intensity of attacks during laser irradiation was observed, but no transfer effect occurred. Additionally the mean temperature gradient after cold exposure was reduced after laser irradiation, while the number of fingers showing prolonged rewarming was unaffected. CONCLUSION Though further studies are necessary to confirm these results we could demonstrate for the first time in a double blind placebo controlled clinical trial that low laser therapy is a potential candidate for an effective therapy of Raynauds phenomenon, although effects seem to be of short duration.

Medizinalbäder zur Therapie der generalisierten Fibromyalgie

Objective: We studied whether whirl baths with plain water or with water containing pine oil or valerian have a different influence on pain, disturbed sleep or tender point count. Methods: A randomized, comparative and investigator-blinded study was performed. Out-patients with generalized fibromyalgia were randomized into three treatment groups. Interventions: Therapy consisted of either whirl bath with plain water or with the addition of pine oil or valerian. The baths were carried out 10 times, three times a week. Main Outcome Measures: General pain, change of pain intensity during the day, general well-being and occurrence of disturbed sleep were recorded before and after the therapy. The number of tender points was assessed by digital palpation, the pain threshold on the shinbone and the middle part of the deltoid muscle was measured by the dolorimeter of A. Fischer. The same instrument was used for recording pain threshold and pain tolerance of both trapezius muscles. The tissue compliance of these muscles was measured as well. Results: 30 out of 39 patients included in the study were evaluated statistically. After treatment with valerian bath (n = 12) well-being and sleep were significantly improved and also the tender point count decreased significantly. Pine oil added to the bath water (n = 7) resulted in a significant improvement of well-being, but unfortunately also in a significant decrease of pain threshold of the shinbone and the right deltoid muscle. Whirl bath in plain water (n = 11) reduced general and maximum pain intensity significantly. Conclusions: Our cautious conclusion of this study is – with respect to the small number of treated patients – that different effects of whirl baths with or without medicinal bath oils can be detected in fibromyalgia patients. Plain water baths modify the pain intensity, medicinal baths improve well-being and sleep.

Application of thermal imaging in forensic medicine

Abstract A thermogram or thermal image provides a two-dimensional map of skin temperature distribution. The technique, which uses the IR radiation of objects as the source for imaging, has significantly developed since it was launched for medical imaging in the 1960s. Modern focal array equipment provides both high spatial and high temperature resolution. Body temperature measurement is a traditional approach to estimating the time of death. A number of protocols have been described for that purpose. Another application for IR imaging is the assessment of environmental conditions of detected corpses (water, cars, weather conditions). Skin burns can be easily visualized by thermal images. Thermal imaging was also used to investigate the skin temperature at the entry point after shots were fired from 0.22–0.38-calibre handguns. Whiplash injuries gained importance in liability cases after car crashes. Occasionally thermal images can provide additional information in this pathology, but this might not be always unambiguous. Thermal imaging was successfully used as an alternative to Polygraph testing. In this application, psychological effects on blood flow are investigated, and an accuracy of 78% in detecting deceptive subjects is reported. Thermal imaging can be used as a method of temperature measurement in a number of applications of forensic medicine. When used for medico-legal evidence, it is important that a standard protocol for subject preparation, image capture and analysis is used. A scheme for standardization of the latter is proposed.

Thermal imaging of skin changes on the feet of type II diabetics

Skin changes such as callosities and mycosis may be regarded as a risk factor for severe structural impairments including ulcers and osteomyelitis in patients suffering from diabetes. Increased temperature of the feet of diabetics is another frequent finding. We investigated the relationship between skin changes and areas of increased skin temperature recorded with an Infrared Scanner AGEMA 870. 76 patients who had type 2 diabetes longer than 5 years, were studied. A physical examination of their feet and nerve conduction tests were performed. Thermal images were taken from both legs in the anterior view, the foot from an anterior view and the soles. 230 sites of high temperature (hot spots) were detected on the thermal images of 75 soles. Toe deformities or deformity of the anterior foot arch, skin callosities, onychomycosis were not related to hot spots on the sole. We confirm that about half of type II diabetes patients present with increased temperatures of their feet. However, no relationship with skin changes and areas of elevated skin temperature could be established. Thermal imaging does not identify the common skin changes found in the feet of diabetics.

Diagnosis of nerve entrapment syndromes by thermal imaging

Thermal images of 154 hands were studied to show that patients suffering from thoracic outlet syndrome or carpal tunnel syndrome can be differentiated from healthy subjects by the occurrence of a thermal asymmetry between the index and the little finger. A temperature difference between these fingers higher than 0.5/spl deg/C was regarded as a pathological finding. With respect to clinical, neurographic and thermographic criteria, hands were allocated into four groups: healthy controls, carpal tunnel syndrome, thoracic outlet syndrome and the combination of carpal tunnel with thoracic outlet syndrome. A discriminant analysis of grouping with respect to the temperature difference between index and little finger, found correct classification in 44,8% of cases. After transfer of the combined syndrome to the thoracic outlet group, the number of correct classifications increased to 63,3%. The calculation for sensitivity and specificity of pathological temperature differences for the diagnosis of thoracic outlet syndrome yielded values of 71,60 and 42,9%. The determination of the temperature distribution on the hand seems to be a valuable test for the detection of patients with thoracic outlet syndrome.