Laser Speckle Contrast Analysis Research Articles

LASCA-imaging of gene-based speckles: application to detection of the gene polymorphism in a bacterial model

A current trend in modern bioinformatics is representation of nucleotide sequences in the form of gene-based (GB) speckles. In this letter GB-speckles have been processed using the s-LASCA (laser speckle contrast analysis) technique. Statistical properties of s-LASCA images of GB-speckles have been analyzed. It is shown that application of the s-LASCA technique allows us to essentially increase the the sensitivity of detection of a single nucleotide polymorphism using GB-speckles.

Assessing Renal Microvascular Reactivity by Laser Speckle-Contrast Imaging in Angiotensin-II-Treated Mice.

IntroductionThe kidney is one of the main organs affected by microvascular damage wrought by hypertension. We developed an approach to investigate renal microcirculatory disturbance in live mice by measuring post-occlusive reactive hyperemia (PORH), a reactivity test exploring endothelial and neuro-microvascular functioning. Laser speckle-contrast analysis (LASCA) assesses microvascular blood flow; it provides real-time images of spatial and temporal blood flow dynamics. We compared basal blood flow and PORH test between control and angiotensin-II-treated mice (Ang-II) to validate the model.ObjectiveThe study objective was to develop an approach to investigate renal microcirculation, and then to compare microvascular reactivity assessed on LASCA in control versus Ang-II mice.MethodsThirty 7-week-old wild-type C57BL/6J mice were allocated into two groups. One received angiotensin-II via osmotic minipumps (Ang-II; n=15); the other served as control (n=15). Basal blood flow was measured on LASCA. The PORH test was then performed in the two groups.ResultsControl mice had significantly lower basal renal microcirculatory flow, expressed in perfusion units (PU), than Ang-II-treated mice (1448 ± 96 vs 1703 ± 185 PU, respectively; P < 0.05). Peak flow was lower in controls than in Ang-II mice (1617±104 vs.1724 ± 205 PU, respectively; P=0.21). Control mice had significantly higher kidney PORH than Ang-II mice (8±3 vs 1±4%, respectively; P < 0.05).ConclusionWe developed an innovative technique to study renal microcirculation in mice. Ang-II-treated mice showed significantly higher basal blood flow than controls, while PORH was significantly higher in controls than in Ang-II mice.

Manifestations of cold sensitivity – a case series

ABSTRACT Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA). Methods: Eight women and four men, ages 22–74, with cold sensitivity were interviewed and examined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming. Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneous perfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards). Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity.

A study of hemodynamics and the structure of capillary blood flow using the method of laser speckle contrast analysis LASCA

The LASCA method can be applied to the study of microcirculation of superficial microvessels. A chicken embryo of the 5th - 7th day of incubation was used as a model of the vascular system. The effect of laser occlusion of a vessel on blood microcirculation in the vascular system was studied. Using the LASCA method, we can conclude about the presence or absence of the blood flow in the vascular system. The contrast value C, calculated by the method, shows the blood redistribution in the vascular system before and after occlusion.

Neuroprotective effects of Ghrelin on traumatic brain injury in mice

Objective To investigate the neuroprotective effect of Ghrelin on traumatic brain injury (TBI) in mice. Methods TBI model of C57BL / 6 mice was established by electronic cortical impact instrument (eCCI). According to the random figure table method, twenty-four mice were randomly divided into sham group(Sham group), TBI group and Ghrelin intervention group(Ghrelin group) with 8 mice in each group. The model of TBI was established in TBI group and Ghrelin group.The mice in Ghrelin group was injected intraperitoneally 0.5 g/kg before and 1 h after injury respectively. And the mice Sham group and TBI group were injected with the same amount of normal saline. The changes of cerebral blood perfusion (CBP) were monitored in real time by laser speckle contrast analysis(LSCI), the changes of neuroelectrophysiology were observed by monitoring motor evoked potential (MEP), and the status of neurological deficit was evaluated by modified neurological deficit score (mNSS). Results Compared with Sham group, the mice in TBI group had significantly lower cerebral blood perfusion(CBP) (t=-12.36, P<0.01), longer latency and lower amplitude of motor evoked potential (MEP) (t=5.03, -11.55, all P<0.01), and significantly higher mNSS scores (t=9.34, P<0.01). However, compared with the TBI group, the cerebral blood perfusion(CBP) of Ghrelin group increased significantly at 12 h after TBI((196.87±17.36) PU/mm2vs (123.62±8.04)PU/mm2, t=10.45, P<0.01), while the latency of MEP decreased((5.30±0.33)ms vs (6.80±0.97)ms, t=-5.01, P<0.01), the amplitude of MEP increased((2.21±0.16)mV vs (1.27±0.27)mV, t=9.65, P<0.01). And compared with the TBI group, the neurological deficit score of Ghrelin group decreased significantly at 24 h after TBI((4.9±1.2) vs (8.4±2.6), t=-3.87, P<0.01). Conclusion Ghrelin exhibits a significant neuroprotective role by increasing cerebral blood flow perfusion, reducing the degree of neurological deficit and promoting motor function recovery in TBI mice. Key words: Traumatic brain injury; Ghrelin; Cerebral blood perfusion; Motor evoked potential; Neuroprotection; Mice

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Aging Impairs Cerebrovascular Reactivity at Preserved Resting Cerebral Arteriolar Tone and Vascular Density in the Laboratory Rat.

The age-related (mal)adaptive modifications of the cerebral microvascular system have been implicated in cognitive impairment and worse outcomes after ischemic stroke. The magnitude of the hyperemic response to spreading depolarization (SD), a recognized principle of ischemic lesion development has also been found to be reduced by aging. Here, we set out to investigate whether the SD-coupled reactivity of the pial arterioles is subject to aging, and whether concomitant vascular rarefaction may contribute to the age-related insufficiency of the cerebral blood flow (CBF) response. CBF was assessed with laser-speckle contrast analysis (LASCA), and the tone adjustment of pial arterioles was followed with intrinsic optical signal (IOS) imaging at green light illumination through a closed cranial window created over the parietal cortex of isoflurane-anesthetized young (2 months old) and old (18 months old) male Sprague–Dawley rats. Global forebrain ischemia and later reperfusion were induced by the bilateral occlusion and later release of both common carotid arteries. SDs were elicited repeatedly with topical 1M KCl. Pial vascular density was measured in green IOS images of the brain surface, while the density and resting diameter of the cortical penetrating vasculature was estimated with micro-computed tomography of paraformaldehyde-fixed cortical samples. Whilst pial arteriolar dilation in response to SD or ischemia induction were found reduced in the old rat brain, the density and resting diameter of pial cortical vessels, and the degree of SD-related oligemia emerged as variables unaffected by age in our experiments. Spatial flow distribution analysis identified an age-related shift to a greater representation of higher flow ranges in the reperfused cortex. According to our data, impairment of functional arteriolar dilation, at preserved vascular density and resting vascular tone, may be implicated in the age-related deficit of the CBF response to SD, and possibly in the reduced efficacy of neurovascular coupling in the aging brain. SD has been recognized as a potent pathophysiological contributor to ischemic lesion expansion, in part because of the insufficiency of the associated CBF response. Therefore, the age-related impairment of cerebral vasoreactivity as shown here is suggested to contribute to the age-related acceleration of ischemic lesion development.

Oxygen Delivery Therapy with EPIFLO Reduces Wound Hyperperfusion in Patients with Chronic Leg Ulcers: A Laser Speckle Contrast Analysis

Today transdermal continuous oxygen therapy (TCOT) is used in wound care to promote healing by improving local hypoxia and preventing infection, and it has been described to reduce local inflammation over 1month of administration. The present study aims to investigate the effects of this treatment on wound microcirculation through laser speckle contrast analysis (LASCA). 20 adult patients (mean age: 76±11.5 years) were prospectively enrolled. Inclusion criteria were presence of venous or mixed lower limb ulcers from three or more months without dimension reduction and without indication to surgery and weekly treatment by our outpatient clinic with silver dressings. Subjects underwent 1month of TCOT (EPIFLO®) in addition tofoam dressing. The primary endpoint was the comparison of ulcer and healthy skin perfusion through LASCA, performed before and after the treatment period. Secondary considered endpointswere wound area, wound area severity index and PUSH Tools 3.0 ulcer severity scales, and pain assessment (Numerical Rating Scale [NRS]). Before treatment, the wound area was significantly more perfused than healthy skin (+45%; P=0.005). At the end of the study, this difference was not significant anymore (+20.5%; P=0.11). Ulcer perfusion decreased (-12.5%, P = 0.047), whereas healthy skin perfusion did not vary significantly. A reduction of the wound dimension (median difference: 2cm; P=0.009) and pain (median difference: 2 NRS point; P<0.001) after therapy were assessed. LASCA shows that 1month of TCOT can help reduce hyperperfusion of ulcer bed in patients with chronic lower limb ulcers, strengthening the hypothesis that this treatment effectively contrasts inflammation. This could correlate with the area and pain reduction assessed; however, the absence of a control group in this study does not allow a generalization of this hypothesis. Larger, controlled trials are needed to properly assess the relationship between TCOT effects on wound microenvironment and effective healing process.

Effect of bloodletting acupuncture at twelve jing-well points of hand on microcirculatory disturbance in mice with traumatic brain injury

To observe the effect of bloodletting acupuncture at twelve jing-well points of hand on microcirculatory disturbance in mice with traumatic brain injury (TBI), and to explore the protective effect of bloodletting therapy on TBI. Sixty clean adult male C57BL/6J mice were randomly divided into a sham-operation group, a model group and a treatment group, 20 mice in each group. The TBI model was established by using electronic controlled cerebral cortex impact instrument in the model group and the treatment group. The mice in the treatment group were treated with bloodletting acupuncture at bilateral "Shaoshang" (LU 11), "Shangyang" (LI 1), "Zhongchong" (PC 9), "Guanchong" (TE 1), "Shaochong" (HT 9) and "Shaoze" (SI 1) immediately after trauma. The mice in the sham-operation group only opened the bone window but did not receive the strike. The regional cerebral blood flow (rCBF) was monitored by laser speckle contrast analysis (LASCA) using a PeriCam PSI System before trauma, immediately after trauma and 1, 2, 12, 24, 48, 72 h after trauma. The brain water content was measured by wet-dry weight method 24 h after trauma. The severity of functional impairment at 2, 12, 24, 48 and 72 h after trauma was evaluated by modified neurological scale scores (mNSS). ① 2 h after trauma, the mNSS in the model group and treatment group were >7 points, suggesting the successful establishment of model; compared with the sham-operation group, the mNSS was increased significantly from 12 to 72 h after trauma in the model group ( all P<0.01), but the mNSS in the treatment group was significantly lower than that in the model group from 2 to 24 h after trauma (P<0.01, P<0.05). ② Compared with the sham-operation group, rCBF in the model group was decreased significantly immediately after trauma (P<0.01), and the rCBF in the model group was lower than that in the sham-operation group from 1 to 72 h after trauma ( all P<0.01); rCBF in the treatment group began to rise and was significantly higher than that in the model group 1-2 h after trauma (P<0.01); 12-48 h after trauma, the increasing of rCBF in the two groups tended to be gentle until 72 h after injury, and rCBF in the model group was decreased while that in the treatment group continued to rise and was higher than that in the model group (P<0.01). ③ 24 h after trauma, the brain water content in the model group was significantly higher than that in the sham-operation group (P<0.01), and brain water content in the treatment group was significantly lower than that in the model group (P<0.01). The bloodletting acupuncture at twelve jing-well points of hand could improve microcirculation disturbance, increase microcirculation perfusion, alleviate secondary brain edema and promote the recovery of nerve function in mice with TBI.

Treatment of resistant Raynaud's phenomenon with single-port thoracoscopic sympathicotomy: a novel minimally invasive endoscopic technique.

ObjectiveTo assess the minimally invasive single-port thoracoscopic sympathicotomy feasibility and efficacy in patients with treatment-resistant RP.MethodsSingle-port thoracoscopic sympathicotomy was performed unilaterally on the left side in eight patients with RP (six males, two females, with a median age of 45.2 years). Five patients had primary and three had secondary RP. Perfusion effects in the hands were assessed at baseline and after 1 month by using a cooling and recovery procedure, and by using laser speckle contrast analysis. Number and duration of RP attacks were reported over a 2-week period.ResultsPatient satisfaction was 100% after surgery. After surgery, a unilateral improvement in perfusion was observed in the left hand compared with the right hand, with cooling and recovery (P = 0.008) and with laser speckle contrast analysis (P = 0.023). In addition, the number and duration of the attacks in the left hand decreased compared with the right hand (both P = 0.028). No serious adverse events occurred in a follow-up period of at least 10 months.ConclusionSingle-port thoracoscopic sympathicotomy is feasible and can be effective in improving hand perfusion in patients with RP. However, long-term efficacy needs to be established.Clinical trial registration numberNCT02680509.

LED-Based Photoacoustic Imaging for Monitoring Angiogenesis in Fibrin Scaffolds

Noninvasive imaging techniques provide insight into physiology that is complementary to tissue morphology obtained by invasive histology. Optical imaging techniques, such as laser speckle contrast analysis, are used in vivo to longitudinally evaluate vascularization. Despite their high spatial resolution, these techniques have a limited imaging depth. In this study, we demonstrate how a dual LED-based photoacoustic (PA) and ultrasound system can delineate changes in perfusion at depth within scaffolds containing basic fibroblast growth factor. Perfusion changes detected by PA corroborated with vessel density. PA imaging could be a noninvasive and sensitive method for evaluating vascularization at depth in larger constructs.

Is there a role for laser speckle contrast analysis (LASCA) in predicting the outcome of digital ulcers in patients with systemic sclerosis?

Digital ulcers (DUs) represent one major burden for patients with systemic sclerosis (SSc). The objectives of our study were to evaluate blood flow in SSc-DUs with laser speckle contrast analysis (LASCA) and to correlate the skin perfusion to clinical and laboratory data. Forty DUs in 31 consecutive patients with SSc according to 2013 ACR/EULAR criteria (20 with limited cutaneous disease, 3 males) were prospectively examined with LASCA. Clinical and laboratory data were collected at the same time. DUs were classified according to clinical features and presence of infection. At LASCA analysis, patients with diffuse SSc had lower mean values of blood flow compared with those with limited disease at the finger affected by DUs (88.80 vs 44.40, p = 0.036) and at the periulcer area (p = 0.041). The presence of infection was associated to a higher flow at the finger with DU (103.02 vs 58.05 p = 0.04), at the level of ulcer (217.63 vs 67.15, p < 0.001), and at the periulcer area (p = 0.001). The ratio between the blood flow at the ulcer area and the finger base (UA/FB) showed a bimodal trend in patients with infected DUs and in those without infections. Infection was positive correlated to the time of healing (HT) (r = 0.648, p = 0.023), while in DUs without infection a negative correlation to HT (r = - 0.46, p = 0.015) was identified. This study demonstrates for the first time that the UA/FB ratio may predict the healing time of DUs in SSc patients and may be crucial for the prognostic stratification of patients. Infection remains one of the main predictors of DU healing.Key Points• The prognostic value of laser speckle contrast analysis (LASCA) in patients with digital ulcers (DUs) in systemic sclerosis remains to be clarified.• LASCA may be able to predict the haling time of the digital ulcers.• The presence of infection of the wound bed may greatly influence the LASCA parameters and the healing time of the digital ulcer.

Non-contact photoacoustic imaging using laser speckle contrast analysis

A novel method for non-contact and continuous detection of photoacoustic signals is presented and experimentally demonstrated. The approach is based on analysis of the contrast of time-varying speckle patterns, and suggests a more robust alternative in respect to interferometric and refractometric available solutions.

Assessment of cerebral hemodynamics during neurosurgical procedures using laser speckle image analysis.

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe medical condition associated with a significant cause of mortality throughout the world. Cisterna magna injection model is accepted widely to mimic clinical aSAH and is performed on small animal models to study aSAH during neurosurgery. Coherent light scattered from the surface of the rat brain is used to infer information about the variations in blood flow during this condition. We obtained speckle images from the exposed cortex during the entire experiment using an external tissue imaging system. Contrast and fractal analyses are carried out for the recorded speckle pattern time series. Correlation analysis based on Hurst exponent for these images is found to be a more sensitive tool in studying aSAH as compared to routinely used laser speckle contrast analysis for assessing the changes in blood flow velocity. Additionally, our studies provide improved blood flow detection sensitivity with image Hurst exponent in combination with computed fractal dimension, during an event of aSAH.

Innovations in the Assessment of Primary and Secondary Raynaud's Phenomenon.

Objectives: Raynaud’s phenomenon (RP) is characterized by intense vasospasm of the digital arteries that causes characteristic color changes in fingers. There are two main types of RP: Primary RP (PRP) and Secondary RP (SRP). PRP is a benign condition. Whilst SRP is associated with several connective tissue diseases (CTD), in particular systemic sclerosis (SSc). The objectives of this report were: to present a short review on morphological (nailfold videocapillaroscopy, NVC) and functional techniques (laser tools and thermography) that allow for a correct diagnosis and treatment of RP and to investigate blood perfusion (BP) by laser speckle contrast analysis (LASCA) in different skin areas of hands and face in PRP, SRP to SSc, and healthy subjects (CNT).Methods: 31 PRP patients (LeRoy criteria), 70 SRP to SSc (ACR/EULAR criteria) and 68 CNT were enrolled. BP was assessed by LASCA at the level different areas of hands and face. NVC was performed to distinguish between PRP and SRP, and to detect the proper pattern of nailfold microangiopathy in SSc patients.Results: Both PRP and SRP showed a statistically significant lower BP than CNT at the level of fingertips (p < 0.0001), periungual (p < 0.0001), palmar aspect of 3rd finger (p < 0.0001), and palm areas (p < 0.0001). Moreover, BP was significantly lower in PRP than in SRP to SSc with the “Early” pattern of microangiopathy in the same areas as above (p < 0.04).Conclusion: By considering a small cohort of patients, BP of hands was found lower in PRP than in SSc patients with the “Early” NVC pattern of microangiopathy.

Aminaphtone Efficacy in Primary and Secondary Raynaud's Phenomenon: A Feasibility Study.

ObjectivesThe aim of this six-month open feasibility study was to evaluate skin blood perfusion and clinical symptom changes during aminaphtone treatment in patients with either primary or secondary Raynaud’s phenomenon to systemic sclerosis.MethodsNinety-two patients referring for Raynaud’s phenomenon have been enrolled in November during routine clinical assessment, after informed consent. Aminaphtone was administered 75 mg twice daily in addition to current treatments to forty-six patients. Skin blood perfusion was measured by Laser Speckle Contrast Analysis (LASCA) at the level of fingertips, periungual areas, dorsum and palm of hands, and face at baseline (W0), after one (W1), four (W4), twelve (W12) and twenty-four (W24) weeks of treatment. Raynaud’s condition score (RCS) and both frequency and duration of Raynaud’s attacks were assessed at the same time.ResultsCompared with the control group, despite colder period of the year, aminaphtone treated patients showed a progressive statistically significant increase of blood perfusion, as well as a decrease of RCS, frequency of Raynaud’s attacks/day and their duration, from W0 to W12 in all skin areas. From W12 to W24 no further increase of blood perfusion was observed. The results were similar in both primary and secondary Raynaud’s phenomenon patients. Five weeks after aminaphtone discontinuation blood perfusion values were significantly higher than those at baseline in the majority of skin areas.ConclusionThis study demonstrates that aminaphtone treatment increases skin blood perfusion and improves Raynaud’s phenomenon clinical symptoms, with sustained efficacy up to 6 months, even in patients with systemic sclerosis. A randomized, blind, controlled, clinical trial including a larger number of subjects is advisable to confirm these early results.

Enhancement of microvessel in laser speckle image using gaussian kernel template

Laser speckle contrast imaging (LSCI) is an optical imaging method, which can monitor microvascular flow variation directly without addition of any ectogenous dye. All the existing laser speckle contrast analysis (LASCA) methods are a combination of spatial and temporal statistics. In this study, we have proposed a new method, Gaussian kernel laser speckle contrast analysis (gLASCA), which processes the raw images primarily with the Gaussian kernel operator along the spatial direction of blood flow. We explored the properties of gLASCA in the simulation and animal cerebral ischemia perfusion model. Compared with the other existing speckle processing methods based on spatial, temporal, spatial-temporal or anisotropic linear structure; the present gLASCA method has a high spatial-temporal resolution to respond the change of velocity especially in microvasculature. Besides, the gLASCA method obtains approximately 10.2% and 7.1% higher contrast-to-noise ratio (CNR) over the anisotropic linear method (aLASCA) in the simulation and experiment models. For these advantages, gLASCA could be a better method for local microvascular laser speckle imaging in terms of cerebral ischemia reperfusion, spreading depression and brain injury diseases.

Gaussian sliding window for robust processing laser speckle contrast images

The laser speckle contrast analysis (LASCA) is one of the most applicable tools in microcirculation studies. While the basic idea, as well as experimental setup for this method, are fairly simple, there is still the room for advancing of data processing algorithms. Specifically, the conventional realizations of LASCA method may limit the spatial and/or temporal resolution and thus fail in the detection of very small contrast objects since they based on the fixed-size rectangular sliding window function. We suggest an alternative data processing algorithm based on the usage of the Gaussian sliding filter for a sequential determination of both spatial and temporal parts of the speckle contrast. The suggested replacement of conventional box filter leads to the monotonic damping of high-frequency spectral components that results in a better elimination of ringing and aliasing effects in the spatio-temporal speckle contrast outputs. Additionally, we show that such sliding filtration increases robustness with respect to the processing of a sequence of nonstabilised images. We support this consideration with representative examples of processing both surrogate and real experimental data.

Comparative pilot study on the effects of pulsating and static cupping on non-specific neck pain and local skin blood perfusion

Abstract Objective To compare the effects of pulsating and static cupping on non-specific neck pain and local skin microcirculation blood perfusion, which is a pilot study. Methods Seventy participants with non-specific neck pain were randomized to the following groups: low-frequency pulsating cupping (LF, n = 20); high-frequency pulsating cupping (HF, n = 20); static cupping (SC, n = 20), or waiting list (WL, n = 10). The LF, HF, and SC received a bilateral 10-minute cupping treatment at Jianzhongshu (SI 15). Outcomes were pain intensity (visual analog scale, VAS), functional status (Neck Disability Index, NDI), and skin blood perfusion at the SI 15, Dazhui (GV 14), and Shenzhu (GV 12) acupoint areas, measured using Laser Speckle Contrast Analysis technology. Results Both LF and HF groups showed a significant reduction in VAS scores compared with the SC group (9.00, 95% CI 1.05–16.95, P = .027; 8.75, 95% CI 0.80–16.70, P = .031). There was no significant difference in VAS scores between the LF and HF groups (P > .05) and between NDI scores measured 3 days after intervention among the four groups (P > .05). In the SI 15 area, blood perfusion in the three treatment groups was higher than that in WL group (P Conclusion This study showed that pulsating cupping may have more favorable analgesic effects on non-specific neck pain compared with static cupping, which may be related to its better effect on improving the local skin blood perfusion.

Riociguat for the Treatment of Raynaud's Phenomenon: A Single-Dose, Double-Blind, Randomized, Placebo-Controlled Cross-Over Pilot Study (DIGIT).

Raynaud's phenomenon (RP) is characterized by transient digital ischemia and is commonly associated with connective tissue disease. Treatment remains unsatisfactory. Here we evaluate the efficacy, safety, and pharmacokinetics of a single dose of the soluble guanylate cyclase stimulator riociguat in RP. DIGIT was a double-blind, randomized, placebo-controlled pilot study. Patients with primary or secondary RP were randomized to a single oral dose of riociguat 2mg or placebo in a cross-over design (7 ± 3days). Efficacy was assessed as placebo-corrected change in digital blood flow 2h post-dose at room temperature (RT) or following cold exposure (CE), measured by laser-speckle contrast analysis. Patients were regarded as responders if placebo-corrected digital blood flow increased by ≥ 10% from baseline at RT or after CE. Of 20 eligible patients, 17 (85%) were female and mean [standard deviation (SD)] age was 52 (13.8) years. Placebo-corrected changes in digital blood flow were + 46% [90% confidence interval (CI) -6 to + 98] at RT and -9% (90% CI -63 to + 44) after CE, with high inter-individual variability. Eight patients (40%) were responders at RT, and 12 (60%) after CE. Riociguat increased mean (SD) digital blood flow in responders at RT by + 136% (114) and in responders following CE by + 39% (53). Riociguat was well tolerated, with few adverse events. In this pilot study, single-dose riociguat was well tolerated in patients with RP and resulted in improved digital blood flow in some patient subsets, with high inter-individual variability. Long-term evaluation is warranted.