Digital thermography of the fingers and toes in Raynaud's phenomenon

Reference Standards for Digital Infrared Thermography Measuring Surface Temperature of the Upper Limbs

(1) Background: although digital infrared thermographic imaging (DITI) is used for diverse medical conditions of the upper limbs, no reference standards have been established. This study aims to establish reference standards by analyzing DITI results of the upper limbs. (2) Methods: we recruited 905 healthy Korean adults and conducted thermography on six regions (dorsal arm, ventral arm, lateral arm, medial arm, dorsal hand, and ventral hand region). We analyzed the data based on the proximity of regions of interest (ROIs), sex, and age. (3) Results: the average temperature (°C) and temperature discrepancy between the right and the left sides (ΔT) of each ROI varied significantly (p < 0.001), ranging from 28.45 ± 5.71 to 29.74 ± 5.14 and from 0.01 ± 0.49 to 0.15 ± 0.62, respectively. The temperature decreased towards the distal ROIs compared to proximal ROIs. The average temperatures of the same ROIs were significantly higher for men than women in all regions (p < 0.001). Across all regions, except the dorsal hand region, average temperatures tended to increase with age, particularly in individuals in their 30s and older (p < 0.001). (4) Conclusions: these data could be used as DITI reference standards to identify skin temperature abnormalities of the upper limbs. However, it is important to consider various confounding factors, and further research is required to validate the accuracy of our results under pathological conditions.

Associations among serum VEGF and CGRP levels with the peripheral vascular blood flow of the skin of the hands in women with Fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a long-term condition of unknown physiopathology, whose hallmark symptoms are diffuse musculoskeletal chronic pain and fatigue.

OBJECTIVES

We aimed to analyze the associations among serum vascular endothelial growth factor (VEGF) and calcitonin gene-related peptide (CGRP) levels with the peripheral temperature of the skin of both hands and the core body temperature in patients with FM and healthy controls.

METHODS

We conducted a case-control observational study with fifty-three women diagnosed with FM and twenty-four healthy women. VEGF and CGRP levels were spectrophotometrically analyzed in serum by enzyme-linked immunosorbent assay. We used an infrared thermography camera to assess the peripheral temperature of the skin of the dorsal thumb, index, middle, ring, and pinkie fingertips and dorsal centre as well as the palm thumb, index, middle, ring, and pinkie fingertips, palm centre and thenar and hypothenar eminences of both hands and an infrared thermographic scanner to record the tympanic membrane and axillary temperature.

RESULTS

Linear regression analysis adjusting for age, menopause status, and body mass index showed that serum VEGF levels were positively associated with the maximum (β = 65.942, 95% CI [4.100,127.784], p = 0.037), minimum (β = 59.216, 95% CI [1.455,116.976], p = 0.045), and mean (β = 66.923, 95% CI [3.142,130.705], p = 0.040) temperature of the thenar eminence of the non-dominant hand, as well as with the maximum temperature of the hypothenar eminence of the non-dominant hand (β = 63.607, 95% CI [3.468,123.747], p = 0.039) in women diagnosed with FM.

CONCLUSIONS

Mild associations were observed between serum VEGF levels and the peripheral temperature of the skin in hand areas in patients with FM; therefore, it is not possible to establish a clear relationship between this vasoactive molecule and vasodilation of the hands in these patients.

Application of a novel finger temperature device in the assessment of subjects with Raynaud's phenomenon

INTRODUCTION

Finger skin thermometry is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. The aim of this study was to evaluate the applicability of a novel finger skin temperature device for performing cold-stimulation test (CST) in subjects with primary and secondary Raynaud's phenomenon (RP).

METHODOLOGY

A total of 155 consecutive subjects were studied. They were divided into three groups: 73 patients with primary RP (8 males, 65 females, mean age 38.5 ± 16.2), 42 patients with secondary RP (4 males, 38 females, mean age 49.6 ± 13.1, connected with lupus erythematosus and systemic scleroderma), and 40 healthy controls (5 males, 35 females, mean age 38.8 ± 16.6). Standardized CST consisting of exposure of both hands to water with a temperature of 10℃ for 5 minutes was performed. Changes in skin temperature of both wrists and 2-5 fingers were measured using a novel finger temperature device (Courage & Khazaka). Measurements were made before and 5, 10, 15, 20, 25, and 30 minutes after cold stimulation. The time of recovery for baseline temperature of all fingers below 15 minutes was considered normal.

RESULTS

The CST was normal in 6 (8.2%) of the patients with primary RP, in 7 (16.6%) of the patients with secondary RP, and in 28 (70%) of the healthy control subjects. The time of complete recovery of baseline temperature with respect to the first finger and for all 2-5 fingers in the three groups was as follows: 24.8 and 28.5 minutes (primary RP), 21.7 and 26.8 minutes (secondary RP), and 11.1 and 15.2 minutes (healthy subjects). Furthermore, the microcirculation was seriously disturbed (rewarming time >31 minutes of all 2-5 digits of both hands) in 54.1% (n = 79), 34.5% (n = 29) and 5% (n = 4) in the same study groups.

DISCUSSION

Our results suggested that skin microcirculation is more disturbed in patients with primary RP than in patients with secondary RP. In support of this unexpected finding were the results reported by Ruaro B. et al (2019). They investigated the blood perfusion (BP) by laser speckle contrast analysis (LASCA) at different skin areas of hands and found that it was significantly lower in primary RP than in secondary RP related to systemic sclerosis.

CONCLUSION

The new finger temperature device used could be considered useful for performing cold-stimulation test in patients with Raynaud's phenomenon.

Infrared Thermography as a Method of Verification in Raynaud's Phenomenon

Raynaud's phenomenon (RP) is characterized by the episodic whitening of the fingers upon exposure to cold. A recently described thermographic algorithm was proposed as a diagnostic replacement of the currently applied finger systolic pressure (FSP) test. The aim of the study was to evaluate the performance of the thermographic algorithm when applied in patients suspected of having RP. Forty-three patients were examined using thermographic imaging after local cooling of the hands in water of 10 °C for 1 min. The thermographic algorithm was applied to predict the probability of RP. The performance of the algorithm was evaluated with different cut-off levels. A new algorithm was proposed based on patients from the target population. The performance of the tested algorithm was noninferior to the FSP test, when a cut-off level of 0.05 was applied, yielding a sensitivity and specificity of 69% and 58%, respectively. The accuracy was 66%. The FSP test had a sensitivity and specificity of 77% and 37%, respectively, and the accuracy was 59%. The thermographic method proved useful for detecting RP and was able to replace the FSP test as a diagnostic test. The alternative algorithm revealed that other thermographic variables were more predictive of the target population, but this should be verified in future patients.

Infrared Thermal Imaging as a Novel Non-Invasive Point-of-Care Tool to Assess Filarial Lymphoedema

Lymphatic filariasis causes disfiguring and disabling lymphoedema, which is commonly and frequently exacerbated by acute dermatolymphangioadenitis (ADLA). Affected people require long-term care and monitoring but health workers lack objective assessment tools. We examine the use of an infrared thermal imaging camera as a novel non-invasive point-of-care tool for filarial lower-limb lymphoedema in 153 affected adults from a highly endemic area of Bangladesh. Temperature differences by lymphoedema stage (mild, moderate, severe) and ADLA history were visualised and quantified using descriptive statistics and regression models. Temperatures were found to increase by severity and captured subclinical differences between no lymphoedema and mild lymphoedema, and differences between moderate and severe stages. Toes and ankle temperatures detected significant differences between all stages other than between mild and moderate stages. Significantly higher temperatures, best captured by heel and calf measures, were found in participants with a history of ADLA, compared to participants who never had ADLA, regardless of the lymphoedema stage. This novel tool has great potential to be used by health workers to detect subclinical cases, predict progression of disease and ADLA status, and monitor pathological tissue changes and stage severity following enhanced care packages or other interventions in people affected by lymphoedema.

Convolutional Neural Networks for Differential Diagnosis of Raynaud’s Phenomenon Based on Hands Thermal Patterns

Raynaud’s phenomenon (RP) is a microvessels’ disorder resulting in transient ischemia. It can be either primary or secondary to connective tissue diseases, such as systemic sclerosis. The differentiation between primary and secondary to systemic sclerosis is of paramount importance to set the proper therapeutic strategy. Thus far, thermal infrared imaging has been employed to accomplish this task by monitoring the finger temperature response to a controlled cold challenge. A completely automated methodology based on deep convolutional neural network is here introduced with the purpose of being able to differentiate systemic sclerosis from primary RP patients by relying uniquely on thermal images of the hands acquired at rest. The classification performance of such a method was compared to that of a three-dimensional convolutional neural network model implemented to classify thermal images of the hands recorded during rewarming from a cold challenge. No significant differences were found between the two procedures, thus ensuring the possibility to avoid the cold challenge. Moreover, the convolutional neural network models were compared with standard feature-based approaches and showed higher performances, thus overcoming the limitations related to the feature extraction (e.g., biases introduced by the operator). Such automated procedures can constitute promising tools for large scale screening of primary RP and secondary to systemic sclerosis in clinical practice.

Characteristic Features of Infrared Thermographic Imaging in Primary Raynaud's Phenomenon

Raynaud’s phenomenon (RP) is characterized by the episodic whitening of the fingers upon exposure to cold. Verification of the condition is crucial in vibration-exposed patients. The current verification method is outdated, but thermographic imaging seems promising as a diagnostic replacement. By investigating patients diagnosed with RP, the study aimed at developing a simple thermographic procedure that could be applied to future patients where verification of the diagnosis is needed. Twenty-two patients with primary RP and 58 healthy controls were examined using thermographic imaging after local cooling of the hands for 1 min in water of 10°C. A logistic regression model was fitted with the temperature curve characteristics to convey a predicted probability of having RP. The characteristics time to end temperature and baseline temperature were the most appropriate predictors of RP among those examined (p = 0.004 and p = 0.04, respectively). The area under the curve was 0.91. The cut-off level 0.46 yielded a sensitivity and specificity of 82% and 86%, respectively. The positive and negative predictive values were 69% and 93%, respectively. This newly developed thermographic method was able to distinguish between patients with RP and healthy controls and was easy to operate. Thus, the method showed great promise as a method for verification of RP in future patients. Trial registration: ClinicalTrials.gov NCT03094910.

Association of core body temperature and peripheral blood flow of the hands with pain intensity, pressure pain hypersensitivity, central sensitization, and fibromyalgia symptoms

Our aim was to analyse body core temperature and peripheral vascular microcirculation at skin hypothenar eminence of the hands and its relationship to symptoms in fibromyalgia syndrome (FMS). A total of 80 FMS women and 80 healthy women, matched on weight, were enrolled in this case-control study. Thermography and infrared thermometer were used for evaluating the hypothenar regions and core body temperature, respectively. The main outcome measures were pain pressure thresholds (PPTs) and clinical questionnaires. Significant associations were observed between overall impact [β = 0.033; 95% confidence interval (95%CI) = 0.003, 0.062; p = 0.030], daytime dysfunction (β = 0.203; 95%CI = 0.011, 0.395; p = 0.039) and reduced activity (β = 0.045; 95%CI = 0.005, 0.085; p = 0.029) and core body temperature in FMS women. PPTs including greater trochanter dominant (β = 0.254; 95%CI = 0.003, 0.504; p = 0.047), greater trochanter non-dominant (β = 0.650; 95%CI = 0.141, 1.159; p = 0.013), as well as sleeping medication (β = -0.242; 95%CI = -0.471, -0.013; p = 0.039) were also associated with hypothenar eminence temperature. Data highlighted that FMS women showed correlations among body core temperature and hand temperature with the clinical symptoms.

Correlation between the infrared thermogram and microvascular abnormalities of the nailfold in patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a multisystemic disease with an extensive microvasculopathy. The gold standard for its investigation is nailfold videocapillaroscopy (NVC).

AIM

To assess the value of thermography (IRT) for the assessment of microvasculopathy in patients with SSc.

MATERIAL AND METHODS

Nineteen patients with limited cutaneous SSc were enrolled in the study. They underwent IRT imaging and NVC. An average temperature (Tavg) at the nailfold and a gradient of temperatures (ΔTavg) between the central metacarpus of the hand and the nailfold was determined for all fingers. NVC pictures were classified to capillaroscopic patterns according to Cutolo et al. system and they were analysed quantitatively to measure the density of capillaries and to calculate capillaroscopic skin ulcers risk index (CSURI) for each finger separately.

RESULTS

There was only a moderate correlation (0.4 < r < 0.6) between thermographic parameters and density of capillaries in fingers II-V (r = 0.5; p < 0.001 for Tavg and r = -0.45; p < 0.001 for ΔTavg), but none in thumbs (r = 0.29; p = 0.089 for Tavg and r = -0.19; p = 0.275 for ΔTavg). Early pattern was associated with a significantly greater surface temperature (Tavg) of nailfolds and essentially milder ΔTavg in fingers II-V when compared to all other capillaroscopic patterns in fingers II-V. Surface temperature (Tavg) was significantly lower and ΔTavg was markedly more pronounced in fingers II-V with a greater risk of development of digital ulcers (DU) calculated by CSURI.

CONCLUSIONS

Although IRT measurements correlate only moderately with density of capillaries, this technique seems to be substantial to determine the capillaroscopic pattern and to identify patients at greater risk of DU development.

Evaluation of sympathetic adrenergic branch of cutaneous neural control throughout thermography and its relationship to nitric oxide levels in patients with fibromyalgia

BACKGROUND

Fibromyalgia syndrome is defined as a complex disease, characterized by chronic widespread musculoskeletal pain and other symptoms. The factors underlying physiopathology of fibromyalgia are not well understood, complicating its diagnosis and management.

OBJECTIVES

To evaluate the peripheral vascular blood flow of the skin of the hands and the core body temperature as indirect measures of sympathetic adrenergic activity of the nervous system and its relationship to nitric oxide levels (NO) in women with fibromyalgia compared with healthy controls.

METHODS

Forty-two women with fibromyalgia and 52 healthy women were enrolled in this observational pilot study. We used infrared thermography of the hands and an infrared dermal thermometer to evaluate the peripheral vascular blood flow and tympanic and axillary core body temperature, respectively. We measured NO levels using the ozone chemiluminescence-based method.

RESULTS

Two-way analysis of covariance (ANCOVA) showed that the tympanic (P=0.002) and hand temperatures were significantly higher in the patients with fibromyalgia than in the controls (P≤0.001). Significant associations were also found between serum NO levels and minimum temperatures at the dorsal center of the dominant hand (β=-3.501; 95% confidence interval [CI] -6.805, ‑0.198; P= 0.038), maximum temperature (β=-5.594; 95% CI ‑10.106, ‑1.081; P=0.016), minimum temperature (β=-4.090; 95% CI ‑7.905, ‑0.275; P=0.036), and mean temperature (β=-5.519; 95% CI ‑9.933, ‑1.106; P=0.015) of the center of the palm of the non-dominant hand, maximum temperature at the thenar eminence of the dominant hand (β=-5.800; 95% CI ‑10.508, ‑1.092; P=0.017), and tympanic temperature (β=-9.321; 95% CI ‑17.974, ‑0.669; P=0.035) in the controls.

CONCLUSIONS

Our findings indicate that the women with fibromyalgia showed higher tympanic core body and hand temperature than the healthy controls. Moreover, there were negative associations between hand peripheral vasodilation and NO in the healthy women but not in those with fibromyalgia, suggesting a dysfunction of sympathetic cutaneous neural control.

Thermography for the detection of Secondary Raynaud's Phenomenon by means of the Distal-Dorsal Distance

Raynaud's phenomenon (RP) is a disease characterized by a transient ischemic process, in an exaggerated vascular response to cold or emotional stress. Thermography is a resource applied to support diagnosis of changes in the circulatory system. The aim of the study was to use the DistalDorsal Thermography Difference (DDD) in thermographic images to assess thermal behavior in individuals with secondary RP. The research was carried out in the period between 2018 and 2019. The sample means of the Distal-consisted of 44 individuals in a control group (Control) and 44 individuals in a pathological group (RP2). The participants, after acclimatization, were submitted to the cold stress protocol. The protocol consisted of immersing hands in a container of water at a temperature of 15°C for 60 seconds. The acquisition of thermographic images was performed at the pre-test moment and at the 1st, 3rd, 5th, 7th, 10th and 15th minute. At each time, the DDD values (of all fingers - minimum, maximum and sum) between the groups were analyzed. For statistical analysis, the independent t test and Cohen's d test were used. Regarding the results, there was a difference in relation to the rate of temperature recovery between the groups. The first group showed a rate of reheating just after the first minute subsequent to the cold stress test, while the RP2 group was unable to recover the temperature over 15 minutes. DDD, regardless of the selected criterion, proved to be a valid index for verifying the temperature gradient in the study with individuals identified with secondary RP.

Pain Intensity, Pressure Pain Hypersensitivity, Central Sensitization, and Pain Catastrophizing Related to Vascular Alterations in Raynaud's Phenomenon: A Preliminary Case-Control Study

OBJECTIVE

To evaluate pain intensity, widespread pressure pain, central sensitization (CS), and catastrophizing between subjects with primary and secondary Raynaud's phenomenon (RP) and healthy controls and to compare the relationships between vascular impairment and pain perception.

METHODS

A preliminary case-control study was performed with a total sample of 57 participants (37 with RP). Sociodemographic data, clinical/vascular data, and pain variables (pain intensity, pressure pain sensitivity, pain magnitude and threshold, CS, and catastrophizing) were registered. Results were analyzed by analysis of covariance and Pearson correlation.

RESULTS

Participants with RP had a lower basal temperature (more vasoconstriction) in their hands (P ≤ 0.012), higher pain intensity (P ≤ 0.001), higher electrical pain magnitude (P < 0.001), and lower pressure pain (P ≤ 0.05) and electrical pain (P < 0.001) thresholds in comparison with healthy controls. Secondary RP participants showed a significantly higher level of CS compared with controls and primary RP participants (P = 0.001). Catastrophizing was higher in the primary and secondary RP (P ≤ 0.001) groups than in controls. No correlations were observed between severity of vasoconstriction and pain variables.

CONCLUSIONS

RP participants showed bilateral hypersensitivity to pressure pain. However, the severity of vascular alterations seems not to be related to central pain experiences. Additional mechanisms such as catastrophizing may influence pain in RP; nevertheless, central sensitization only appears to be involved in the secondary form of RP.

Human Tongue Thermography Could Be a Prognostic Tool for Prescreening the Type II Diabetes Mellitus

Diabetes mellitus is one of the life threatening diseases over the globe, and an early prediction of diabetes is of utmost importance in this current scenario. International Diabetes Federation (IDF) reported nearly half of the world's population was undiagnosed and unaware of being developed into diabetes. In 2017, around 84 million individuals were living with diabetes, and it might increase to 156 million by the end of 2045 stated by IDF. Generally, the diagnosis of diabetes relies on the biochemical method that may cause uneasiness and probability of infections to the subjects. To overcome such difficulties, a noninvasive method is much needed around the globe for primary screening. A change in body temperature is an indication of various diseases. Infrared thermal imaging is relatively a novel technique for skin temperature measurement and turned out to be well known in the medical field due to being noninvasive, risk-free, and repeatable. According to traditional Chinese medicine, the human tongue is a sensitive mirror that reflects the body's pathophysiological condition. So, we have (i) analysed and classified diabetes based on thermal variations at human tongue, (ii) segmented the hot spot regions from tongue thermogram by RGB (red, green, blue) based color histogram image segmentation method and extracted the features using gray level co-occurrence matrix algorithm, (iii) classified normal and diabetes using various machine learning algorithms, and (iv) developed computer aided diagnostic system to classify diabetes mellitus. The baseline measurements and tongue thermograms were obtained from 140 subjects. The measured tongue surface temperature of the diabetic group was found to be greater than normal. The statistical correlation between the HbA_1c and the thermal distribution in the tongue region was found to be r² = 0.5688. The Convolutional Neural Network has outperformed the other classifiers with 94.28% accuracy rate. Thus, tongue thermograms could be used as a preliminary screening approach for diabetes prognosis.

Potential for the application of dynamic skin thermography after local hypothermia

Infrared thermography is one of the widely used non-invasive diagnostic methods. While the procedure is mainly used for early malignant tumor diagnostics, a potential application for thermography was proposed in cardiovascular, skin, autoimmune diseases, arthritis, Reynaud’s syndrome, burns, surgery and therapeutic treatment monitoring. The method of thermographic evaluation has not changed significantly since the end of 20th century. In this study we attempted to characterize the influence of skin capillary blood flow on surface temperature recuperation following local hypothermia. To improve sensitivity and standardize the procedure we developed a study protocol that involves minimizing or excluding the influence of external factors on study results. An original applicator was used to apply dosed hypothermia. Massive porcine tissue block was chosen as a passive model without active heat and mass transfer but with heat capacity, structure and heat dissipation characteristics similar to human tissues. 51 healthy volunteers were assigned to control group, while 16 patients with diabetes mellitus constituted the main study group. Cumulative temperature difference was calculated in all cases. It was 121,8 ± 70,8 °С×s in the control group, 95,6 ± 54,4 °С×s in the main study group and 307,2 ± 43,4 °С×s in the passive model. Based on the study results, we made the following conclusions: absence of heat and mass transfer in the passive model complicates heat balance recuperation due to layered structure of the skin; heat balance recuperation curve is an individual parameter and is not influenced by age or gender.

Raynaud's phenomenon manifesting as progressive abnormal MRI bone marrow signal in the toes

Objective

The purpose of this report is to discuss the presentation and the progressive magnetic resonance imaging (MRI) findings in a single patient with clinically-diagnosed Raynaud's phenomenon (RP).

Conclusion

RP can present as non-specific toe pain and manifest as progressive abnormal MRI bone marrow signal in the toes. In addition to patient presentation and clinical assessment, this information could contribute to earlier diagnosis and treatment of RP and other coexisting rheumatologic disorders.

Comparison between thermal recovery in women with Raynaud's Phenomenon and not diagnosed women using thermography

Thermography detects the infrared radiation emanated from bodies and transduces it in electrical analog signal. It has application as a complementary exam in several medical segments, including the reheating study to detect diseases like Raynaud's Phenomenon (RP). In this way, the aim of this study is to compare the heating behavior of the RP women and not diagnosed (ND) women for selection of diagnosis criteria. This retrospective study was undertaken in the city of Curitiba, Brazil. For the study, twenty-four volunteer women, with the age range of 30-70 years, were taken to participate of a survey, 12 of them have the clinical diagnostic of Secondary Raynauld's Phenomenon, and twelve women were not diagnosed. Volunteers answered an anamnesis and had the central body temperature measured. They were oriented to keep the hands free and to do not touch anything during 15 minutes for acclimatization. Then, the hands were immersed for 60 seconds in a container with water at 10 °C. New pictures were taken every five minutes during twenty minutes after the immersion. The heating curve of the right hand shows that RP women's hands are colder than ND women and are slower to reheat the temperature after cold stress. The ring (fourth finger) has a linear behavior in both hands. It was the coldest one and the slowest to reheat. Statistical difference was observed in critical times of reheating at 15 and 20 minutes after the cold stress. These results show that this finger could become a reference in studies to determine cutting points and to facilitate the clinical diagnosis of RP.

Secondary Raynaud's Phenomenon and Skin Necrosis of Toes in the Paraplegic Patient with Hypertension

We present two cases of paraplegic patients who developed secondary Raynaud’s phenomenon. A 43-year-old man with paraplegia presented with dark purple discoloration and skin defects on his left second and third toes and complained of a cold sensation in both feet for a period of 1 year. He had been taking diuretics for 4 years. The capillary refilling time for both affected toes was delayed. His antihypertensive drug was changed to a calcium channel blocker under suspicion of Raynaud’s phenomenon aggravated by hydrochlorothiazide, and the capillary refilling time normalized within 3 days. The toe skin defect was covered with a skin graft. A 51-year-old man with paraplegia presented with cyanotic color change and recurrent unstable wounds on his toes. He was also taking diuretics for hypertension. Suspecting secondary Raynaud’s phenomenon aggravated by diuretics, we changed the diuretics to olmesartan medoxmil 20 mg and amlodipine besylate 2.5 mg per day. Subsequently, he has had no unstable wounds for 30 months. If hypertensive patients with paraplegia complain of skin discoloration in their extremities, Raynaud’s phenomenon should be considered and the antihypertensive drug may need to be stopped in order to improve the wound-healing process.

Infrared thermal imaging in connective tissue diseases

Infrared thermal imaging (IRT) is a non-invasive, non-contact technique which allows one to measure and visualize infrared radiation. In medicine, thermal imaging has been used for more than 50 years in various clinical settings, including Raynaud’s phenomenon and systemic sclerosis. Imaging and quantification of surface body temperature provides an indirect measure of the microcirculation’s overall performance. As such, IRT is capable of confirming the diagnosis of Raynaud’s phenomenon, and, with additional cold or heat challenge, of differentiating between the primary and secondary condition. In systemic sclerosis IRT has a potential role in assessing disease activity and monitoring treatment response. Despite certain limitations, thermal imaging can find a place in clinical practice, and with the introduction of small, low-cost infrared cameras, possibly become a part of routine rheumatological evaluation.

[Use of infrared thermography in ophthalmology]

Thermoregulation disorders are associated with Body temperature fluctuation. Both hyper- and hypothermia are evidence of an ongoing pathological process. Contralateral symmetry in the Body heat spread is considered normal, while asymmetry, if above a certain level, implies an underlying pathology. Infrared thermography (IRT) is employed in many medical fields including ophthalmology. The earliest attempts of eye surface temperature evaluation were made in the 19^th century. Over the last 50 years, different authors have been using this method to assess ocular adnexa, however, the technique remains insufficiently studied. The reported IRT data is often contradictory, which may be due to heterogeneity (in terms of severity) of patient groups and disparities between research parameters.

Postocclusive Hyperemia Measured with Laser Doppler Flowmetry and Transcutaneous Oxygen Tension in the Diagnosis of Primary Raynaud's Phenomenon: A Prospective, Controlled Study

The aim of this study was to measure the sensitivity and specificity of transcutaneous oxygen tension and postocclusive hyperemia testing using laser Doppler flowmetry in patients with primary Raynaud's phenomenon. One hundred patients and one hundred controls were included in the study. Baseline microvascular blood flow and then time to peak flow following occlusion were measured using laser Doppler flowmetry. Afterwards, the transcutaneous oxygen tension was recorded. The sensitivities of baseline microvascular blood flow, postocclusive time to peak flow, and transcutaneous oxygen tension were 79%, 79%, and 77%, respectively. The postocclusive time peak flow had a superior specificity of 90% and area under the curve of 0.92 as compared to 66% and 0.80 for baseline microvascular flow and 64% and 0.76 for transcutaneous oxygen tension. Time to postocclusive peak blood flow measured by laser Doppler flowmetry is a highly accurate test for differentiating patients with primary Raynaud's phenomenon from healthy controls.

Abnormal Bone Marrow Signal Intensity in the Phalanges of the Foot as a Manifestation of Raynaud Phenomenon: A Report of Six Patients

OBJECTIVE

The objectives of our study were to describe the MRI findings of pedal phalangeal bone marrow edema in patients with Raynaud phenomenon (RP) and discuss the clinical implications of these MRI findings.

CONCLUSION

There is a progressive distal-to-proximal pattern of pedal phalangeal bone marrow edema on MRI in patients with RP. This knowledge may allow early diagnosis and treatment of rheumatologic disorders that are potentially associated with RP.

Some selected quantitative methods of thermal image analysis in Matlab

The paper presents a new algorithm based on some selected automatic quantitative methods for analysing thermal images. It shows the practical implementation of these image analysis methods in Matlab. It enables to perform fully automated and reproducible measurements of selected parameters in thermal images. The paper also shows two examples of the use of the proposed image analysis methods for the area of ​​the skin of a human foot and face. The full source code of the developed application is also provided as an attachment. The main window of the program during dynamic analysis of the foot thermal image.