Medical applications of infrared thermography: A review.

The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

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Pathogenesis of Raynaud's phenomenon

Classification of factors influencing the use of infrared thermography in humans: A review

Raynaud's phenomenon is common but often comes to medical attention only after many years This review updates the understanding of the pathogenesis, the approach to management, and current approaches to drug therapy

Raynaud's Phenomenon

Background: Longitudinal study to define a scoring system to quantify the specific capillary abnormalities, as observed by capillary microscopy in systemic sclerosis (SSc). Methods: Ninety patients with SSc were evaluated by nailfold videocapillaroscopy for an average of 72 (SD 23) months. Enlarged and giant capillaries, haemorrhages, loss of capillaries, disorganisation of the microvascular array, and capillary ramifications were the evaluated parameters identifying the “scleroderma patterns”. A semiquantitative rating scale to score these altered microvascular parameters was adopted (score 0–3). A “microangiopathy evolution score” (sum of three scores: loss of capillaries, disorganisation of the microvascular array and capillary ramifications) was also selected to assess the progression of the vascular damage. Results: At the end of the follow-up, the score for each nailfold videocapillaroscopy parameter significantly changed. The microangiopathy evolution score significantly increased in 53 of 90 patients (59%) indicating a worsening of the microangiopathy. On the contrary, 22 patients (24%) showed a significant decrease of the evolution score suggesting an improvement of the microangiopathy and no changes were detected in 15 patients with SSc (17%). Conclusions: The capillaroscopic score was found to be a sensitive tool to quantify and monitor the SSc microvascular damage. Furthermore, the microangiopathy evolution score might be used to survey the evolution of the microvascular damage, as the relative scores increase during the progression of the SSc.

https://ard.bmj.com/content/annrheumdis/early/2007/11/23/ard.2007.079756.full.pdf

Scoring the nailfold microvascular changes during the capillaroscopic analysis in systemic sclerosis patients

OBJECTIVE: To develop a computer based nailfold video capillaroscopy system with enhanced image quality and to assess its disease-subgroup resolving power in patients with primary and secondary Raynaud9s phenomenon (RP). METHODS: Using frame registration software, digitized video images from the microscope were combined to form a panoramic mosaic of the nailfold. Capillary dimensions (apex, arterial, venous, and total width) and density were measured onscreen. Significantly, the new system could guarantee analysis of the same set of capillaries by 2 observers. Forty-eight healthy control subjects, 21 patients with primary RP, 40 patients with limited cutaneous systemic sclerosis (lcSSc), and 11 patients with diffuse cutaneous SSc (dcSSc) were studied. Intra- and interobserver variability were calculated in a subset of 30 subjects. RESULTS: The number of loops/mm was significantly lower, and all 4 capillary dimensions significantly greater, in SSc patients versus controls plus primary RP patients (p

https://www.jrheum.org/content/jrheum/32/5/841.full.pdf

Computerized nailfold video capillaroscopy--a new tool for assessment of Raynaud's phenomenon.

Changes in the microvasculature are considered to play an important part in the pathogenesis of psoriasis and its associated arthritis. The novel method of nailfold video capillaroscopy is an extension of the technique of widefield nailfold microscopy which has been of diagnostic and predictive use in the in vivo study of the microcirculation in systemic sclerosis and other connective tissue disorders. However, similar studies in patients with psoriasis and psoriatic arthritis and/or nail changes have produced conflicting results. We tested the hypothesis that any abnormalities in nailfold capillaries of either a quantitative or qualitative nature might be observed more readily in subjects with pathology adjacent to the nailfold, i.e. distal interphalangeal (DIP) joint changes and/or nail dystrophy, when using this technique. Forty-four patients with psoriasis were recruited (21 males, 23 females). Twelve patients had psoriasis alone, 13 had psoriasis and nail changes, six had DIP joint involvement with changes of psoriasis elsewhere, and 13 had psoriasis, DIP arthritis and nail changes. Capillary density and standard capillary dimensions were studied and compared with those of 44 age- and sex-matched control subjects. There was a significant (P < 0.05) decrease in capillary loop density in patients with either psoriasis plus nail disease (14.5 +/- 5.7 capillaries per 3 mm field) or psoriasis plus nail and DIP joint disease (14.3 +/- 5. 0) when compared with controls (19.2 +/- 3.8). In patients with psoriatic arthritis affecting the DIP joints, there was a statistically significant (P < 0.05) decrease in arterial and venous capillary limb diameters, and this was also seen in those with arthritis associated with nail changes. However, there was no difference in capillary dimensions between patients with psoriasis and/or nail changes when compared with normal controls. Morphological abnormalities previously described in the literature were not noted in any of our four patient groups. Our findings of diminution in both nailfold capillary bed density and dimensions of the arterial and venous capillary limbs suggest that vascular injury, previously noted in ultrastructural studies, may play a part in the pathogenesis of psoriatic arthritis. However, in contrast to previous studies, we found no specific pattern of a morphological nature of nailfold capillaries in patients with psoriasis with or without nail changes, when compared with normal controls.

Nailfold video capillaroscopy in psoriasis.

Comparison of thermography and laser Doppler imaging in the assessment of Raynaud's phenomenon.

SUMMARY The aim of the study was to measure nailfold capillary dimensions and capillary density in patients with primary Raynaud's phenomenon (PRP) and systemic sclerosis (SSc) compared to control subjects. Ten controls, nine patients with PRP and 10 patients with SSc were studied. All dimensions other than distance between limbs were significantly increased in both the PRP and SSc groups compared to controls (P < 0.01), with the SSc group showing the most marked increases (SSc vs PRP, P < 0.05 for all dimensions). Capillary density was significantly reduced in the SSc group compared to controls (P = 0.004). These results suggest that structural vascular changes occur in PRP as well as in SSc, and that PRP may, therefore, not be entirely benign. THE technique of wide-field capillary microscopy has for many years been used in the assessment of patients with connective tissue disease [1], and abnormalities in patients with systemic sclerosis (SSc), including capillary dilatation and loop dropout, are well recognized. Photographing the nailfold allows subsequent examination of the capillaries with measurement of capillary density. More recently, video capillaroscopy, which has the advantage of allowing immediate measurement of individual capillaries using a video camera and digitizing system, is emerging as a useful tool in the assessment of the microvasculature of patients with Raynaud's phenomenon. In this study, we used this technique of video capillaroscopy to compare nailfold capillary dimensions and capillary density in patients with primary Raynaud's phenomenon (PRP), SSc and healthy control subjects.

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Increased nailfold capillary dimensions in primary raynaud's phenomenon and systemic sclerosis

Objective. To conduct a retrospective study to assess whether the degree of thumb involvement differs between primary Raynaud’s phenomenon (PRP) and secondary Raynaud’s phenomenon (SRP). Methods. Thermography images from all patients attending Salford Royal Hospital and referred for thermography for assessment of RP between 2004 and 2006 were retrospectively reviewed. A distal dorsal difference (DDD) of −1°C or less between the fingertips and dorsum of the hand (fingers cooler) at 23°C was considered clinically relevant. The worse score (the lower score, i.e., the more negative value) from each pair of digits was considered for analysis. Results. One hundred seventy patients fulfilled the study criteria. DDD at 23°C for the thumbs were significantly higher (digital tips warmer) compared with other digits (p Conclusion. Although the median temperature gradient along the thumb was not significantly different between SRP and PRP, the thumb is more likely to be involved in SRP than in PRP. Thumb involvement is one of a number of clinical indicators that should alert the clinician to the possibility of an underlying connective tissue disease/disorder.

https://www.jrheum.org/content/jrheum/37/4/783.full.pdf

Tonia Moore

Papers

Computerized nailfold video capillaroscopy--a new tool for assessment of Raynaud's phenomenon.

Nailfold video capillaroscopy in psoriasis.

Comparison of thermography and laser Doppler imaging in the assessment of Raynaud's phenomenon.

Increased nailfold capillary dimensions in primary raynaud's phenomenon and systemic sclerosis

Thumb Involvement in Raynaud’s Phenomenon as an Indicator of Underlying Connective Tissue Disease