Search

Significance: Effective vein visualization is critically important for several clinical procedures, such as venous blood sampling and intravenous injection. Existing technologies using infrared device or ultrasound rely on professional equipment and are not suitable for daily medical care. A regression-based vein visualization method is proposed. Aim: We visualize veins from conventional RGB images to provide assistance in venipuncture procedures as well as clinical diagnosis of some venous insufficiency. Approach: The RGB images taken by digital cameras are first transformed to spectral reflectance images using Wiener estimation. Multiple regression analysis is then applied to derive the relationship between spectral reflectance and the concentrations of pigments. Monte Carlo simulation is adopted to get prior information. Finally, vein patterns are visualized from the spatial distribution of pigments. To minimize the effect of illumination on skin color, light correction and shading removal operations are performed in advance. Results: Experimental results from inner forearms of 60 subjects show the effectiveness of the regression-based method. Subjective and objective evaluations demonstrate that the clarity and completeness of vein patterns can be improved by light correction and shading removal. Conclusions: Vein patterns can be successfully visualized from RGB images without any professional equipment. The proposed method can assist in venipuncture procedures. It also shows promising potential to be used in clinical diagnosis and treatment of some venous insufficiency.

Significance: There is an essential need to develop wearable multimodality technologies that can continuously measure both blood flow and oxygenation in deep tissues to investigate and manage various vascular/cellular diseases. Aim: To develop a wearable dual-wavelength diffuse speckle contrast flow oximetry (DSCFO) for simultaneous measurements of blood flow and oxygenation variations in deep tissues. Approach: A wearable fiber-free DSCFO probe was fabricated using 3D printing to confine two small near-infrared laser diodes and a tiny CMOS camera in positions for DSCFO measurements. The spatial diffuse speckle contrast and light intensity measurements at the two different wavelengths enable quantification of tissue blood flow and oxygenation, respectively. The DSCFO was first calibrated using tissue phantoms and then tested in adult forearms during artery cuff occlusion. Results: Phantom tests determined the largest effective source–detector distance (15 mm) and optimal camera exposure time (10 ms) and verified the accuracy of DSCFO in measuring absorption coefficient variations. The DSCFO detected substantial changes in forearm blood flow and oxygenation resulting from the artery occlusion, which meet physiological expectations and are consistent with previous study results. Conclusions: The wearable DSCFO may be used for continuous and simultaneous monitoring of blood flow and oxygenation variations in freely behaving subjects.

In a pilot study of 11 healthy adults (24 to 39 years, all male), we characterize the influence of external probe pressure on optical diffuse correlation spectroscopy (DCS) measurements of pulsatile blood flow obtained on the forearm and forehead. For external probe pressure control, a hand inflatable air balloon is inserted between the tissue and an elastic strap. The air balloon is sequentially inflated to achieve a wide range of external probe pressures between 20 and 250 mmHg on the forearm and forehead, which are measured with a flexible pressure sensor underneath the probe. At each probe pressure, the pulsatility index (PI) of arteriole blood flow on the forehead and forearm is measured with DCS (2.1-cm source-detector separation). We observe a strong correlation between probe pressure and PI on the forearm (R=0.66, p

Background The ideal gentle cleansing product is one that effectively removes soils while minimizing damage to the skin. Thus, measuring physical abrasion caused by cleansing tissues is critical to the continued development of gentle cleansing products. Current analysis of cleansing materials for skin gentleness is time consuming and requires expensive human subject testing. This report describes the development of a rapid and inexpensive bench assay for the assessment of skin abrasion caused by wiping. Methods Coefficient of friction (COF) evaluations using bench methods were compared with results from clinical studies of repeated wiping and with confocal visualizations of excised skin. A Monitor/Slip and Friction™ instrument (model 32-06; TMI, Amityville, NY, USA) was used to measure tissue friction on simulated skin (Vitro-Skin®, N19-5X; IMS, Milford, CT, USA). Clinical data from a 4-day repetitive forearm wiping study measuring transepidermal water loss (TEWL) in 30 subjects was compared with results from the bench top assay. In addition, excised skin samples were also treated using the COF bench assay and examined using confocal microscopy to visualize stratum corneum damage caused by wiping. Results Using the bench COF assay, we were able to distinguish between bath tissue codes by comparing average static friction value (ASFV) for the test codes, where lower ASFV indicated less abrasive tissue. The ASFV followed the same gentleness trend observed in the clinical study. Confocal microscopy of excised skin wiped with the same materials indicated stratum corneum damage consistent with the bench COF and clinical TEWL observations. Conclusion We observed significant correlation between bench and clinical methods for measuring skin damage caused by wiping of skin with tissue. The bench method will facilitate rapid and inexpensive skin gentleness assessment of cleansing materials.

We have compared the fatty acids of the capillary and venous whole blood samples collected on the commercially developed blood collection paper and standard grade filter paper extracted by either the direct methylation or conventional method (including various blood lipids fractions). Also, reproducibility of fatty acids extracted from dried blood on the filter paper after storing at room temperature up to 2 months and at 4 °C up to 6 months was assessed. In conclusion, the direct methylation of fingertip blood collected on both brand of papers produced fatty acids that reflected venous blood fatty acids extracted by the conventional method. Of the eight fatty acids evaluated, capillary DHA showed the strongest correlation with DHA of the venous whole lipids as well as various lipid fractions of the plasma and red cells. However, a prolonged storage of blood samples at 4 °C had deleterious effect on the qualitative value of fatty acids, especially DHA.

Background/purpose: Cold and allergy sufferers often develop irritation around the nostrils as a result of repeated and frequent rubbing of the skin site with facial tissues. This irritation is a combination of the inherent irritant properties of the tissue components (chemical irritation), and mechanical irritation from friction. Lotion-coated facial tissues are being developed to provide soothing, skin benefits, and to promote healing of this type of irritation. The objective of these studies was to evaluate the efficacy of different lotion formulations on facial tissues in preventing irritation, or aiding in the healing of irritation. Methods: The modified forearm-controlled application test (Modified FCAT) was adapted as a means of quickly evaluating the relative skin benefits of various lotion formulations used to coat facial tissues. The test was conducted on the volar surface of the forearms of volunteer subjects. Test sites were pretreated with 24 h occlusive patches of sodium lauryl sulfate (SLS) to induce mild or moderate skin irritation. This was followed by repeated wiping of the lotion-coated tissues. Irritation was evaluated using visual scoring for erythema and dryness. Lotion formulation options were compared in the model. Comparisons included assessments of the type of fatty alcohol in the formulation (stearyl and cetearyl alcohol), the presence of silicone and the base formulation (mineral oil, petrolatum of a proprietary formula). Results: Differences in the degree of erythema and dryness were detected among various formulation options. No differences were found between formulations containing stearyl or cetearyl alcohol. Low levels of silicone produced benefits in one of two experiments. The proprietary base formula produced greater reductions in erythema following treatment of SLS-irritated skin compared with mineral oil and petrolatum bases. Conclusions: The results indicated that this modification of the FCAT can be used to compare various lotion formulations for skin benefits and healing properties, and to rank qualitatively the benefits of various formulation options.

To validate nerve-axon reflex-related vasodilatation as an objective method to evaluate C-nociceptive fibre function by comparing it with the standard diagnostic criteria.Neuropathy was evaluated in 41 patients with diabetes (26 men and 15 women) without peripheral vascular disease by assessing the Neuropathy Symptom Score, the Neuropathy Disability Score (NDS), the vibration perception threshold (VPT), the heat detection threshold (HDT), nerve conduction parameters and standard cardiovascular tests. The neurovascular response to 1% acetylcholine (Ach) iontophoresis was measured at the forearm and at both feet by laser flowmetry. An age-matched and sex-matched control group of 10 healthy people was also included.Significant correlations were observed between the neurovascular response at the foot and HDT (r(s) = -0.658; p0.0001), NDS (r(s) = -0.665; p0.0001), VPT (r(s) = -0.548; p = 0.0005), tibial nerve conduction velocity (r(s) = 0.631; p = 0.0002), sural nerve amplitude (r(s) = 0.581; p = 0.0002) and autonomic function tests. According to the NDS, in patients with diabetes who had mild, moderate or severe neuropathy, a significantly lower neurovascular response was seen at the foot than in patients without neuropathy and controls. A neurovascular response50% was found to be highly sensitive (90%), with a good specificity (74%), in identifying patients with diabetic neuropathy.Small-fibre dysfunction can be diagnosed reliably with neurovascular response assessment. This response is already reduced in the early stages of peripheral neuropathy, supporting the hypothesis that small-fibre impairment is an early event in the natural history of diabetic neuropathy.

PURPOSE To compare gentleness of a silicone tape to a paper tape and to an untreated control. DESIGN Controlled, randomized, grader-blinded cohort trial. SUBJECTS AND SETTING The sample group comprised 28 healthy volunteers aged 55 years and older (median age = 63 years) with a Fitzpatrick Skin Type of I, II, or III. All volunteers were recruited from the greater Philadelphia area and the study was conducted at a dermatological research facility specializing in noninvasive instrumental measurements. METHODS Tapes were applied and removed daily (excluding weekends) to 2 of 3 sites on the left and right volar forearms over an 11-day period. The center site on each forearm was left untreated and tapes were randomized to the proximal and distal sites. The primary assessment was transepidermal water loss (TEWL); secondary assessments included erythema/edema, denudation/skin-stripping, and subject self-evaluations. Study personnel conducting the primary and secondary assessments were not involved with treatments to maintain the blinded nature of the study. The identity of the 2 tapes was not revealed to the subjects until after conclusion of the study. RESULTS On day 11 the mean TEWL value for the paper tape was significantly higher than that for both the untreated control and silicone tape (P < .001). End-of-study mean TEWL values were 2.65 ± 0.68 g/mh for the silicone tape, 6.85 ± 4.97 g/mh for the paper tape, and 3.73 ± 1.19 g/mh for the untreated control. At all assessments, the silicone tape exhibited net changes from baseline that were significantly less than the paper tape (P < .05 day 1, P < .001 days 4, 7, and 11) and similar for the untreated control. Only at days 4 (P < .01) and 11 (P < .001) was the paper tape significantly higher than that for the untreated control. Throughout the study, both tapes exhibited mean TEWL values within the range of normal intact forearm skin, indicating that both tapes were gentle. No differences in erythema/edema scores occurred but the silicone tape resulted in lower denudation/skin-stripping scores than the paper tape at days 4 to 11 (P < .0001). Self-assessment of pain at removal was low for both tapes but significantly lower for the silicone tape (days 1-7, P = .02; day 11, P = .009). Forty-four percent of participants expressed a preference for the silicone tape as compared to the paper tape (19%), with 37% stating no preference. CONCLUSIONS Based on TEWL assessment of disruption of the stratum corneum water barrier, the silicone tape proved gentler to the skin than the paper tape. After 9 applications and removals over 11 days of study, the silicone tape was similar to the untreated control, whereas the paper tape exhibited significantly higher mean TEWL values than both the untreated control and the silicone tape. Expert grader assessments corroborate these findings. These data indicate that the silicone tape may provide additional gentleness when it is clinically needed.

Objective: To determine the sensitivity and specificity of clinical tests for detecting focal lesions in a prospective blinded study. Methods: 46 patients with a focal cerebral hemisphere lesion without obvious focal signs and 19 controls with normal imaging were examined using a battery of clinical tests. Examiners were blinded to the diagnosis. The sensitivity, specificity, and positive and negative predictive values of each test were measured. Results: The upper limb tests with the greatest sensitivities for detecting a focal lesion were finger rolling (sensitivity 0.33 (95% confidence interval, 0.21 to 0.47)), assessment of power (0.30 (0.19 to 0.45)), rapid alternating movements (0.30 (0.19 to 0.45)), forearm rolling (0.24 (0.14 to 0.38)), and pronator drift (0.22 (0.12 to 0.36)). All these tests had a specificity of 1.00 (0.83 to 1.00). This combination of tests detected an abnormality in 50% of the patients with a focal lesion. In the lower limbs, assessment of power was the most sensitive test (sensitivity 0.20 (0.11 to 0.33)). Visual field defects were detected in 10 patients with a focal lesion (sensitivity 0.22 (0.12 to 0.36)) and facial weakness in eight (sensitivity 0.17 (0.09 to 0.31)). Overall, the examination detected signs of focal brain disease in 61% of the patients with a focal cerebral lesion. Conclusions: The neurological examination has a low sensitivity for detecting early cerebral hemisphere lesions in patients without obvious focal signs. The finger and forearm rolling tests, rapid alternating movements of the hands, and pronator drift are simple tests that increase the detection of a focal lesion without greatly increasing the length of the examination.

Objective: To apply the lesion method to assess neuroanatomical substrates for judgments of forearm orientation from proprioceptive cues in humans. Methods: Participants were 15 subjects with chronic unilateral brain lesions and stable behavioural deficits, and 14 neurologically normal controls. Subjects aligned the forearm to earth fixed vertical and trunk fixed anterior-posterior (A-P) axes ("straight ahead"), with the head aligned to the trunk and with head and shoulder orientations varied on each trial. Results: Most subjects with posterior parietal lobe lesions made larger variable errors than controls in aligning the forearm to the earth fixed vertical axis and the trunk A-P axes, whether the head was held upright or oriented in different positions. Lesion subjects and controls made similar constant errors for aligning the forearm to gravitational vertical. Variable error magnitude correlated positively with greater lesion volume of right and left superior parietal lobules (SPL), but not with lesions in other brain areas. Larger variable errors for aligning the forearm to the trunk fixed A-P axis were also correlated with the volume of SPL lesions, but constant error magnitude correlated with larger volume lesions in premotor areas, inferior parietal lobules, and posterior regions of the superior temporal gyri, but not with SPL lesion volume. Conclusions: The findings suggest that the right and left superior and inferior parietal lobules, posterior superior temporal gyri, and premotor areas play a role in defining higher level coordinate systems for specifying orientation of the right and left forearm.