Deep Learning-Based Wrist Vascular Biometric Recognition.

The need for contactless vascular biometric systems has significantly increased. In recent years, deep learning has proven to be efficient for vein segmentation and matching. Palm and finger vein biometrics are well researched; however, research on wrist vein biometrics is limited. Wrist vein biometrics is promising due to it not having finger or palm patterns on the skin surface making the image acquisition process easier. This paper presents a deep learning-based novel low-cost end-to-end contactless wrist vein biometric recognition system. FYO wrist vein dataset was used to train a novel U-Net CNN structure to extract and segment wrist vein patterns effectively. The extracted images were evaluated to have a Dice Coefficient of 0.723. A CNN and Siamese Neural Network were implemented to match wrist vein images obtaining the highest F1-score of 84.7%. The average matching time is less than 3 s on a Raspberry Pi. All the subsystems were integrated with the help of a designed GUI to form a functional end-to-end deep learning-based wrist biometric recognition system.

[Trifid median nerve. A rare anatomical variant in sonographic evaluation of carpal tunnel]. / Nervio mediano trífido. Una variante anatómica infrecuente en la exploración ecográfica del túnel del carpo.

The ultrasound study for the diagnosis of carpal tunnel syndrome can reveal different anatomical variants. A rare variant is the presence of a trifid median nerve. The visualization of this anatomical variant may be of importance in the surgical planning of carpal tunnel syndrome. Fifty-two-year-old male, with a clinic compatible with bilateral carpal tunnel syndrome. In the ultrasound examination, a bifid median nerve appears as a finding in the right wrist and a trifid median nerve in the left wrist as anatomical variants. It is important to distinguish a trifid median nerve from a persistent median artery at the level of the carpal tunnel, much more frequent than the first. For this, the ultrasound visualization of the study area using the Doppler function is essential.

Outcomes of Wrist-Access Deep Venous Embolization Following Percutaneous Fistula Creation: A Two-Year Single Center Experience.

PURPOSE: During percutaneous arteriovenous (pAVF) fistula creation, deep venous embolization is recommended to encourage superficial venous flow development. The safety of crossing adjacent to the newly formed fistula from wrist venous access has not been established. The purpose of this study was to evaluate the safety and efficacy of antegrade deep venous embolization after creation of the pAVF. MATERIALS: A retrospective analysis was performed of all procedural data related to pAVF creation using the Wavelinq device from October 2019 to November 2021. Patient data from the hospital information systems were collected where the venous access for fistula creation was from the wrist-access (ulnar or radial vein) and where deep venous embolization was performed after forming the fistula and crossing adjacent to the anastomosis. Thirty-nine patients were identified. RESULTS: Twenty pAVFs were created from wrist ulnar vein access and 19 from radial vein access. The accessed veins were used for embolization of the brachial veins central to the newly created anastomosis. No pAVFs were lost by crossing adjacent to the anastomotic area to perform deep venous embolization at time of creation. There were no major complications, specifically bleeding, infection, pseudoaneurysm formation. Rates of minor complications consisted of two coil migrations to the right atrium requiring uneventful retrieval (5%). Follow-up ultrasound data showed no evidence of delayed complications. CONCLUSION: In this single center experience crossing alongside the anastomosis of a newly formed percutaneous fistula from an antegrade venous approach was safe with no risk of loss of the pAVF.

Bifid median nerve as an anatomical risk factor for carpal tunnel syndrome: A meta-analysis.

As the median nerve enters the carpal tunnel, it is a single nerve that soon bifurcates into lateral and medial branches into the hand. If the bifurcation is proximal to the carpel tunnel, a bifid median nerve (BMN) results. Carpal tunnel syndrome is often associated with a BMN with or without a persistent median artery. Individual keywords and MeSH phrases were searched in the Google Scholar, SCOPUS, and PubMed databases. Full texts were then collected and assessed for suitability. The prevalence of BMN at the wrist joint in normal and carpal tunnel syndrome wrists (precanal part) and the mean difference between groups were recorded. Only human data were used to test the findings. The pooled odds ratio (with minimal heterogeneity) was 1.50 [1.17-1.93, 95% CI]. The BMN cross-sectional area (CSA) was significantly greater than that of a solitary median nerve in normal wrists. The mean difference in CSA between the two was 1.50 mm2 [0.56-2.45 mm2 , 95% CI] without heterogeneity (i2  = 0). Sex and laterality distributions scarcely differed between the two types of wrists. Owing to the insufficiency of data, the relationships with mean height and weight were not examined. There was a 50% greater incidence of bifid median nerves in carpal tunnel syndrome patients than in normal subjects. A bifid median nerve increases the mean CSA at the wrist joint by 1.5 mm2 . These findings indicate that the bifid median nerve is an anatomical risk factor for carpal tunnel syndrome.

Cuffless blood pressure monitoring from a wristband with calibration-free algorithms for sensing location based on bio-impedance sensor array and autoencoder.

Continuous monitoring of blood pressure (BP) is essential for the prediction and the prevention of cardiovascular diseases. Cuffless BP methods based on non-invasive sensors integrated into wearable devices can translate blood pulsatile activity into continuous BP data. However, local blood pulsatile sensors from wearable devices suffer from inaccurate pulsatile activity measurement based on superficial capillaries, large form-factor devices and BP variation with sensor location which degrade the accuracy of BP estimation and the device wearability. This study presents a cuffless BP monitoring method based on a novel bio-impedance (Bio-Z) sensor array built in a flexible wristband with small-form factor that provides a robust blood pulsatile sensing and BP estimation without calibration methods for the sensing location. We use a convolutional neural network (CNN) autoencoder that reconstructs an accurate estimate of the arterial pulse signal independent of sensing location from a group of six Bio-Z sensors within the sensor array. We rely on an Adaptive Boosting regression model which maps the features of the estimated arterial pulse signal to systolic and diastolic BP readings. BP was accurately estimated with average error and correlation coefficient of 0.5 ± 5.0 mmHg and 0.80 for diastolic BP, and 0.2 ± 6.5 mmHg and 0.79 for systolic BP, respectively.

Variations ignored in routine wrist MRI reports: prevalence of the median nerve anatomical variations and persistent median artery.

BACKGROUND: It is vital to know the anatomical variations of the wrist to avoid iatrogenic injuries during carpal tunnel (CT) surgery. PURPOSE: To determine the anatomical variations of the median nerve (MN) and the prevalence of persistent median artery (PMA) on wrist magnetic resonance imaging (MRI). MATERIAL AND METHODS: A total of 300 wrists evaluated by MRI during 2013-2015 were retrospectively identified. While branching of the MN distal to the CT is accepted as the normal anatomy, proximal to the tunnel and within the tunnel were considered as variations. The prevalence of PMA was also evaluated. The patients were assigned to groups according to age, gender, and wrist side and compared to determine whether there was any significant difference in terms of these variations. All evaluations were assessed with the shared decision of a musculoskeletal radiologist and a radiology resident. RESULTS: Of the 300 wrists, 38 (12.7%) and 34 (11.3%) had a bifid MN proximal to the CT and within the CT, respectively. Only one nerve trifurcation was seen within the CT. The MN exhibited branching distal to the CT in 227 (76%) patients. PMA was observed in 44 (14.7%) patients. Of the 44 PMA cases, 28 (63.6%) also had a coexisting MN variation. There was no significant difference in the prevalence of MN variations and PMA in the subgroups (P > 0.05). CONCLUSION: Nearly one in four patients (24.4%) have MN variations and 14.8% had PMA. Preoperative evaluation of these common anatomical variations with MRI will be protective against postoperative complications of CT surgery.

Wrist Extension Does Not Change the Position of the Radial Artery: Cadaveric Study With Application to Arterial Line Placement, and Transradial Neurointerventional Procedures.

BACKGROUND: The radial artery is gaining popularity as a vascular access site for neurointerventional procedures. However, recent analyses of wrist position and radial artery anatomy has suggested that the extended position of the wrist is not always necessary. Therefore, the following cadaveric study was performed to verify these findings. METHODS: Twenty adult cadaveric upper limbs underwent dissection of the radial artery. The radial artery was exposed but left in its anatomical position. With the hand supinated, the wrist was extended to 45 degrees and 90 degrees. Observations were then made of any movement of the artery during these ranges of motion. Next, a tension gauge was attached to the radial artery and any tension on the artery measured during the above noted ranges of motion. RESULTS: During extension of the wrist, none of the radial artery specimens was found to move in any direction. Moreover, an average of only 0.28 N of tension on the artery was found with wrist extension up to 90 degrees. Our cadaveric study found that, contrary to popular belief, extension of the wrist during cannulation of the radial artery does not change the position of the artery nor does it significantly alter the tension on the artery. CONCLUSIONS: These data support several recent clinical studies.

Monitoring the Patient Following Radio-Cephalic Arteriovenous Fistula Creation: Current Perspectives.

Autogenous radial-cephalic direct wrist arteriovenous fistula (RC-AVF) in the non-dominant arm is the gold standard for dialysis vascular access. However, the RC-AVF non-maturation rate is significant (≃ 40%) due to an increasingly elderly and comorbid population incidence. A detailed identification of the biological cascade underlying arteriovenous fistula (AVF) maturation could be the key to clinical research aimed at identify the group of patients at risk of primary AVF failure. Currently, careful post-operative monitoring remains the most crucial aspect to overcome the problem of impaired maturation. Up to 80% of patients with immature RC-AVF have problems potentially solvable with early endovascular or surgical correction. Physical examination by experienced practitioners in conjunction with duplex ultrasound examination (DUS) can identify physical signs of non-maturation, understand the underlying cause, and drive for a tailored early planning to treat the complication. New approaches for the early assessment of AVF maturation are under study. Techniques to promote RC-AVF maturation performed through the administration of pre-or peri-operative drugs have missed up to now to prove an efficacy in improving fistula success. The new techniques tested after surgery appear to hold future promise for improving fistula maturation.

Contemporary outcomes of a "snuffbox first" hemodialysis access approach in the United States.

OBJECTIVE: The Society for Vascular Surgery guidelines for permanent hemodialysis (HD) access creation recommend prioritizing the most distal possible autogenous access to minimize complications and preserve more proximal options. The "snuffbox" arteriovenous fistula (AVF) is the most distal radial artery-cephalic vein AVF. Despite the theoretical benefits of the snuffbox approach, recent trends have been toward upper arm access. Our study sought to investigate the feasibility of a snuffbox-first strategy for HD access in all anatomically appropriate candidates. METHODS: From January 2016 to August 2019, all patients with end-stage renal disease (ESRD) or pre-ESRD under consideration for HD access were evaluated for a snuffbox-first approach by a team of vascular surgeons and nephrologists at a single, urban academic medical center in the United States. Data were collected prospectively and supplemented by medical record review. A survival analysis was performed to evaluate primary unassisted and secondary patency and clinical and functional maturation. Patients were censored if they had received a kidney transplant or had died. Cox proportional hazards regression was used to determine the risk factors for prolonged clinical maturation and functional maturation. RESULTS: A total of 55 snuffbox AVFs were created. The median patient age was 60 years (interquartile range [IQR], 52-70 years), and 52.7% of the patients were men. The median follow-up was 369 days (IQR, 166-509 days). The median survival for primary unassisted patency was 90 days (95% confidence interval [CI], 79-111). Secondary patency at 1 year was 92.3% (95% CI, 85.3%-99.9%). The clinical maturation rate at 1 year was 83.7% (n = 55; 95% CI, 66.8%-91.9%), and the functional maturation rate at 1 year was 85.6% (n = 40; 95% CI, 63.3%-94.4%). Of the patients who were pre-ESRD at AVF creation and had initiated HD during the study period, 87.5% had successfully received incident HD with their snuffbox AVF. Twenty-four patients were receiving HD via a catheter at snuffbox creation. Of those patients, the functional maturation rate at 1 year was 82.5% (95% CI, 44.8%-94.4%). The patients had undergone a median of two interventions (IQR, zero to seven interventions) in the first year. Of these, 46.9% were percutaneous angioplasty and 31.2% were side-branch ligation. Diabetes was associated with slower AVF clinical maturation (multivariate hazard ratio, 0.35; 95% CI, 0.15-0.82; P = .016). A larger artery diameter was associated with earlier AVF clinical maturation (multivariate hazard ratio, 6.64; 95% CI, 2.11-20.9). CONCLUSIONS: A snuffbox-first approach to HD access is a viable option for distal access creation in a cohort of patients requiring HD in the United States. Subsequent ancillary interventions to facilitate access maturation were required for most patients.

High-resolution, non-contrast-enhanced magnetic resonance angiography of the wrist, hand and digital arteries using optimized implementation of Cartesian quiescent interval slice selective (QISS) at 1.5 T.

PURPOSE: Non-contrast-enhanced (CE) magnetic resonance angiography (MRA) techniques are of considerable interest for diagnosing vascular diseases in the upper extremities owing to the possibility of repeated examinations, sufficient coverage of the measurement volume, and because possible side effects of administering iodine- or gadolinium-based contrast agents and radiation exposure can be avoided. The aim of this study was to investigate the feasibility of an optimized electrocardiogram (ECG) triggered Cartesian quiescent interval slice selective (QISS) technique for MRA of hand arteries. MATERIAL AND METHODS: Both hands of 20 healthy volunteers (HVs) were examined using an optimized QISS-MRA pulse sequence at 1.5 Tesla. The wrist and hand arterial trees were divided into 36 segments. Cross-sectional areas (CSA) of all arterial segments were measured. For the technical evaluation of the pulse sequence, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were computed and six imaging artifacts were graded. Two experienced observers used an ordinal scoring system to assess the image quality of each arterial segment. Interobserver agreement was determined. RESULTS: The median CSA was 7.3 mm2 in the ulnar and radial artery, 3.2 mm2 in the four common digital arteries, and 1.5 mm2 in five proper digital arteries. The median SNR and CNR of the third common proper arteries were 45.9 and 20.3, respectively. None of the arterial segments were contaminated by venous enhancement. The image quality of arterial segments for both hands was considered as diagnostic in 87.2% of all 1440 segments. An interobserver agreement of 0.67 for both hands was determined for image quality of arterial segments using a five-grade scoring system. Optimized QISS-MRA allows as the first MRA technique the classification of superficial palmar arch (SPA) and deep palmar arch (DPA) variants. 5 new SPA and 6 new DPA variants could be classified using QISS-MRA in comparison with previous studies using CE computed tomography angiography and using fixed cadaver hands. CONCLUSIONS: By using this optimized 2D Cartesian QISS-MRA protocol, contrast agent-free angiography of the wrist and hand arteries provided a high in-plane spatial resolution and an excellent visualization of small digital arteries.

Creating percutaneous radiocephalic arteriovenous fistulas at the wrist.

BACKGROUND: The first arteriovenous fistulas were created at the wrist more than 60 years ago. Basic surgical construction techniques remain unchanged with mobilization and repositioning of the vessels followed by a sutured anastomosis. We used the Ellipsys device to construct percutaneous radiocephalic-arteriovenous fistulas at the wrist and report the results. METHODS: Data were reviewed retrospectively for all patients who had a percutaneous radiocephalic-arteriovenous fistula created during a 6-month period. Each individual underwent ultrasound vessel mapping in addition to physical examination. When a radiocephalic-arteriovenous fistula was feasible and a communicating vein ⩾ 2 mm in diameter was noted in the distal forearm along with a radial artery ⩾ 2 mm, a percutaneous radiocephalic-arteriovenous fistula was considered and reviewed with the patient. RESULTS: Four individuals met the criteria to consider a percutaneous radiocephalic-arteriovenous fistula and all elected to have the procedure performed. Ages were 54-85 years. Three were diabetic and one was female. All percutaneous radiocephalic-arteriovenous fistulas were technically successful. Two individuals had not yet started dialysis therapy. Successful and repetitive cannulation for the two individuals with catheters was initiated at 4 and 8 weeks post procedure. The two pre-dialysis patients had physiologic arteriovenous fistula maturation (6 mm vein diameter and >500 mL/min flow) at 4 and 12 weeks. There were no procedural or late complications and none required intervention. Follow-up was 8-23 months (mean 16 months). CONCLUSION: The success of these percutaneous radiocephalic-arteriovenous fistulas suggests that use of the Ellipsys device will be applicable at the wrist in selected patients where appropriate vessel sizes and configurations are found.

End-to-side versus side-to-side anastomosis with distal vein ligation for arteriovenous fistula creation.

INTRODUCTION: There is lack of compelling evidence about the best technique to carry out the anastomosis between the artery and the vein: end to side or side to side. This issue was addressed by very few randomized controlled studies. This topic has recently re-emerged with the advent of the endovascular fistula creation using the side-to-side technique.Objectives: To compare the results of both surgical techniques for the creation of arteriovenous anastomosis. METHODS: This is a randomized controlled prospective study. All renal failure patients, 18 years and older, referred to our institution requiring creation of a new arm arteriovenous fistulas, including distal radio-cephalic, ulno-basilic, proximal brachio-cephalic or brachio-basilic configurations were included. RESULTS: Between February 2018 and October 2018, 378 patients underwent creation of permanent haemodialysis access. A total of 100 patients were randomized equally into the end-to-side and side-to-side groups. Follow-up for the study purpose continued until May 2019 (mean = 9 months, range 1-12). Patients' age ranged from 19 to 68 years. Sevety-seven arteriovenous fistulas were created at the elbow (37 brachio-basilic and 40 brachio-cephalic). Radio-cephalic fistulae were 23, created at wrist and in the forearm. Primary technical success was 97%, and 35 (70%) and 17 (34%) cases achieved functionally maturation in the end-to-side and side-to-side groups, respectively (P = 0.0001). Primary and secondary patency rates at 12 months were 76% end to side versus 78% STS (P = 0.381) and 84% end to side versus 86% STS (P = 0.225), respectively. CONCLUSION: End-to-side technique should be used in all instances of arteriovenous fistulas creation.

Effects of Photobiomodulation Therapy and Restriction of Wrist Extensor Blood Flow on Grip: Randomized Clinical Trial.

Objective: To evaluate the influence of two different photobiomodulation therapy (PBMT) protocols (red 660 nm vs. infrared 830 nm) combined with a blood flow restriction (BFR) training protocol in wrist extensor muscles on handgrip, wrist extension force, and electromyographic behavior [root mean square (RMS)]. Background: PBMT has been widely used to increase muscle performance and recovery in recent clinical trials. However, there is no evidence whether PBMT (red and/or infrared) can promote better results when combined with BFR, a known method to induce better strength gains. Methods: This study was a randomized controlled trial including 58 volunteers allocated into four groups: (1) control (conventional strengthening), (2) BFR (strengthening with BFR), (3) 660 nm (BFR strengthening with 660 nm PBMT-35 mW; 0.05 cm2; 2.10 J, total energy 18.9 J), and (4) 830 nm (BFR strengthening with 830 nm PBMT-32 mW; 0.101 cm2; 1.92 J, total energy 17.2 J). Data were analyzed by using a mixed-effects model, with a 5% significance index. Results: A statistically significant increase was obtained for handgrip strength for the 660 nm group [27.36 ± 2.61 kilogram force (kgF)] compared with the 830 nm group (23.04 ± 3.06 kgF) (p = 0.010) and for wrist extensor strength in the 660 nm (7.77 ± 0.58 kgF) and BFR (7.54 ± 0.92 kgF) groups compared with the control group (5.33 ± 0.61 kgF) (p = 0.001 and p = 0.004, respectively). The RMS value for the 660 nm group was significantly higher than control (p < 0.0001), BFR (p < 0.0001), and the 830 nm group (p = 0.0009). Conclusions: The association of PBMT (660 nm) and BFR was effective for increasing handgrip strength of the wrist extensors, associated with an increase in RMS.

Photoplethysmographic evaluation of generalized tonic-clonic seizures.

OBJECTIVE: Photoplethysmography (PPG) is an optical technique measuring variations of blood perfusion in peripheral tissues. We evaluated alterations in PPG signals in relationship to the occurrence of generalized tonic-clonic seizures (GTCSs) in patients with epilepsy to evaluate the feasibility of seizure detection. METHODS: During electroencephalographic (EEG) long-term monitoring, patients wore portable wristband sensor(s) on their wrists or ankles recording PPG signals. We analyzed PPG signals during three time periods, which were defined with respect to seizures detected on EEG: (1) baseline (>30 minutes prior to seizure), (2) preseizure period, and (3) postseizure period. Furthermore, we selected five random control segments during seizure-free periods. PPG features, including frequency, amplitude, duration, slope, smoothness, and area under the curve, were automatically calculated. We used a linear mixed-effect model to evaluate changes in PPG features between different time periods in an attempt to identify signal changes that detect seizures. RESULTS: We prospectively enrolled 174 patients from the epilepsy monitoring unit at Boston Children's Hospital. Twenty-five GTCSs were recorded from 13 patients. Data from the first recorded GTCS of each patient were included in the analysis. We observed an increase in PPG frequency during pre- and postseizure periods that was higher than the changes during seizure-free periods (frequency increase: preseizure = 0.22 Hz, postseizure = 0.58 Hz vs changes during seizure-free period = 0.05 Hz). The PPG slope decreased significantly by 56.71 nW/s during preseizure periods compared to seizure-free periods. Additionally, the smoothness increased significantly by 0.22 nW/s during the postseizure period compared to seizure-free periods. SIGNIFICANCE: Monitoring of PPG signals may assist in the detection of GTCSs in patients with epilepsy. PPG may serve as a promising biomarker for future seizure detection systems and may contribute to future seizure prediction systems.

Photoplethysmography: A measure for the function of the autonomic nervous system in focal impaired awareness seizures.

OBJECTIVES: Photoplethysmography (PPG) reflects variations of blood perfusion in tissues, which may signify seizure-related autonomic changes. The aim of this study is to assess the variability of PPG signals and their value in detecting peri-ictal changes in patients with focal impaired awareness seizures (FIASs). METHODS: PPG data were recorded using a wearable sensor placed on the wrist or ankle of children with epilepsy admitted for long-term video-electroencephalographic monitoring. We analyzed PPG data in four different periods: seizure-free, preictal, ictal, and postictal. Multiple features were automatically extracted from the PPG signal-frequency, duration, amplitude, increasing and decreasing slopes, smoothness, and area under the curve (AUC)-and were used to identify preictal, ictal, or postictal changes by comparing them with seizure-free periods and with each other using a linear mixed-effects model. RESULTS: We studied PPG in 11 patients (18 FIASs), including seizure-free, preictal, and postictal periods, and a subset of eight patients (12 FIASs) including the ictal period. Compared to the seizure-free period, we found significant changes in PPG (1) during the ictal period across all features; (2) during the preictal period in amplitude, duration, increasing slope, and AUC; and (3) during the postictal period in decreasing slope. SIGNIFICANCE: Specific PPG changes can be seen before, during, and after FIASs. The peri-ictal changes in the PPG features of patients with FIASs suggest potential applications of PPG monitoring for seizure detection.

Venous distensibility is more important than venous diameter in primary survival of autogenous radiocephalic arteriovenous fistulas.

BACKGROUND: Many studies suggested that the optimal cephalic vein diameter for wrist radio-cephalic arteriovenous fistula construction should be at least 2 mm to predict successful maturation and primary patency. However, our experience has shown that many patients with smaller cephalic vein diameter (≤2 mm) in the neutral state (without a tourniquet) also have good clinical outcomes. The aim of this study was to identify predictors that affect primary survival of new wrist radio-cephalic arteriovenous fistula in patients with cephalic vein diameter ≤2 mm. METHODS: We performed a retrospective review of 50 patients with preoperative cephalic vein diameters ≤2 mm in the neutral state who underwent wrist radio-cephalic arteriovenous fistula construction between September 2016 and October 2019. Internal diameters of the cephalic vein and radial artery, venous distensibility, peak systolic velocity, and resistance index of the radial artery were determined by ultrasound examination before wrist radio-cephalic arteriovenous fistula placement. Patients were divided into two groups: failure and survival. RESULTS: The radio-cephalic arteriovenous fistula survival rate was 68% from the time of radio-cephalic arteriovenous fistula creation until the end of the study. Univariate analysis showed that larger venous distensibility (p < 0.001), non-diabetic kidney disease (p = 0.009), and slower peak systolic velocity of the radial artery (p = 0.033) were predictive factors for primary radio-cephalic arteriovenous fistula survival. Multivariate regression analysis revealed good venous distensibility (odds ratio = 9.637, 95% confidence interval = 1.893-49.050, p = 0.006) and non-diabetic kidney disease (odds ratio = 0.148, 95% confidence interval = 0.033-0.660, p = 0.012) to be independent predictors for primary radio-cephalic arteriovenous fistula survival. Receiver operating characteristic analysis showed that venous distensibility >0.52 mm (sensitivity: 70.6%, specificity: 68.8%) was the best cut-off value to predict primary radio-cephalic arteriovenous fistula survival. CONCLUSION: When cephalic veins with diameter ≤2 mm are found, venous distensibility should be used to aid in the surgery decision-making process. The outcome of wrist radio-cephalic arteriovenous fistula survival would be significantly improved through the use of cephalic vein with venous distensibility >0.52 mm.

Description and analysis of the dynamic and morphological flow pattern of the main arteries of the wrist and hand in a healthy spanish population. / Descripción y análisis del patrón de normalidad de flujo dinámico y morfológico de las arterias principales de la muñeca y mano en población sana española.

BACKGROUND AND AIM: The vascular anatomy of the hand has already been widely described macroscopically. However, there are very few papers that study the pattern of normality of in vivo vascularisation that describe and analyse the main arteries of the hand. The aim of this paper was to carry out a study to serve as a reference for the normal values of size and flow of the radial and ulnar artery at the level of the wrist, and the digital radial and ulnar arteries at the level of the fingers. MATERIAL AND METHOD: A descriptive observational cross-sectional study on 200 hands in 100 healthy volunteers aged between 20-30years. Doppler-colour ultrasound was performed on the ulnar and radial arteries in the wrist, as well as on the radial and ulnar digital arteries in each finger. Once the measurements had been taken, a general comparative analysis was performed also taking laterality, dominance and gender into account. RESULTS: It was observed that the radial artery is larger in size than the ulnar at wrist level, however, it was the ulnar artery that showed flow dominance at this level. At finger level, the arteries are greater in size and flow in the areas of the fingers more protected from injury (digital ulnar artery in the first three and radial artery in the fourth and fifth digits).

Wrist Vascular Biometric Recognition Using a Portable Contactless System.

Human wrist vein biometric recognition is one of the least used vascular biometric modalities. Nevertheless, it has similar usability and is as safe as the two most common vascular variants in the commercial and research worlds: hand palm vein and finger vein modalities. Besides, the wrist vein variant, with wider veins, provides a clearer and better visualization and definition of the unique vein patterns. In this paper, a novel vein wrist non-contact system has been designed, implemented, and tested. For this purpose, a new contactless database has been collected with the software algorithm TGS-CVBR®. The database, called UC3M-CV1, consists of 1200 near-infrared contactless images of 100 different users, collected in two separate sessions, from the wrists of 50 subjects (25 females and 25 males). Environmental light conditions for the different subjects and sessions have been not controlled: different daytimes and different places (outdoor/indoor). The software algorithm created for the recognition task is PIS-CVBR®. The results obtained by combining these three elements, TGS-CVBR®, PIS-CVBR®, and UC3M-CV1 dataset, are compared using two other different wrist contact databases, PUT and UC3M (best value of Equal Error Rate (EER) = 0.08%), taken into account and measured the computing time, demonstrating the viability of obtaining a contactless real-time-processing wrist system.

Differences in pulse rate variability with measurement site.

BACKGROUND: Recently, attempts have been made to use the pulse rate variability (PRV) as a surrogate for heart rate variability (HRV). PRV, however, may be caused by the fluctuations of left ventricular pre-ejection period and pulse transit time besides HRV. We examined whether PRV differs not only from HRV but also depending on the measurement site. RESULTS: In five healthy subjects, pulse waves were measured simultaneously on both wrists and both forearms together with single-lead electrocardiogram (ECG) in the supine and sitting positions. Although average pulse interval showed no significant difference from average R-R interval in either positions, PRV showed greater power for the low-frequency (LF) and high-frequency (HF) components and lower LF/HF than HRV. The deviations of PRV from HRV in the supine and sitting positions were 13.2% and 7.9% for LF power, 24.5% and 18.3% for HF power, and - 15.0% and - 30.2% for LF/HF, respectively. While the average pulse interval showed 0.8% and 0.5% inter-site variations among the four sites in the supine and sitting positions, respectively, the inter-site variations in PRV were 4.0% and 3.6% for LF power, 3.8% and 4.7% for HF power, and 18.0% and 17.5% for LF/HF, respectively. CONCLUSIONS: These suggest that PRV shows not only systemic differences from HRV but also considerable inter-site variations.