curved vessels
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2022 ◽  
Vol 11 (2) ◽  
pp. 375
Author(s):  
Magdalena Żychowska ◽  
Adam Reich

Background: (Video)dermoscopy is a non-invasive diagnostic technique that has a well-established role in dermatooncology. In recent years, this method has also been increasingly used in the assessment of inflammatory dermatoses. So far, little is known about the (video)dermoscopic features of dermatomyositis (DM). Methods: Consecutive patients with DM were included in the study and videodermoscopic assessments of the nailfolds, scalp, and active skin lesions were performed. Results: Fifteen patients with DM (10 women and 5 men) were included. Capillaroscopy showed elongated capillaries (90.9%), avascular areas (81.8%), disorganized vessel architecture (81.8%), tortuous capillaries (72.7%), dilated capillaries (72.7%), and hemorrhages (72.7%). The trichoscopic findings included linear branched vessels (80.0%), linear vessels (60.0%), linear curved vessels (53.3%), perifollicular pigmentation (40.0%), perifollicular erythema (33.3%), scaling (20.0%), white (20.0%) or yellow (20%) interfollicular scales, and white (20.0%) or pinkish (13.3%) structureless areas. Polymorphic vessels of an unspecific distribution and white or pink structureless areas were frequently observed under dermoscopy in cutaneous manifestations of DM, including Gottron’s papules and Gottron’s sign. Conclusions: Dermoscopy of the nailfolds (capillaroscopy), scalp (tricoscopy), and active cutaneous lesions may be of value in the preliminary diagnosis of DM.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jing Gao ◽  
Wenmin Fei ◽  
Changbing Shen ◽  
Xue Shen ◽  
Minghui Sun ◽  
...  

Objective: Dermoscopic features of cutaneous vascular anomalies have been reported, but the described features currently known are limited and not well-understood. The aim of this study is to comprehensively summarize and compare the dermoscopic features of the four different types of cutaneous vascular anomalies [infantile hemangiomas (IH), cherry angioma (CA), angiokeratomas (AK), and pyogenic granuloma (PG)] in the Chinese Han population.Materials and Methods: Dermoscopic features of 31 IH, 172 CA, 31 AK, and 45 PG were collected based on the contact non-polarized mode of dermoscopy at 20-fold magnification. Dermoscopic features including background, lacunae, vessel morphology and distribution were collected and summarized. Additionally, we compared these features by age stage, gender, and anatomical locations in CA.Results: The dermoscopic features of IH included the red lacunae, red/red-blue/red-white backgrounds, and vessel morphology such as linear curved vessels, serpiginous vessels, coiled vessels. For CA, the lacunae appeared reddish brown to reddish blue or only red. In terms of vascular morphology, serpentine vessels, coiled vessels, looped vessels, and curved vessels could be seen in the lesions. A few lesions were black or presented with a superficial white veil. There were statistical differences in red background (P = 0.021), unspecific vessel distribution (P = 0.030), black area (P = 0.029), and white surface (P = 0.042) among different age groups. Red-brown lacunae (P = 0.039), red-blue (P = 0.013), red-white background (P = 0.015), black area (P = 0.016), and white surface (P = 0.046) were of statistical difference in terms of the locations of lesions. Lacunae were also observed in AK, which presented with red, dark purple, dark blue, black. Global dermoscopic patterns that were characterized by a homogeneous area were obvious in all PG lesions, among which 30 (66.7%) were red-white and 15 (33.3%) were red. As for local features, “white rail” lines were detected in 19 (42.2%) lesions and white collarette was seen in 34 (75.6%) lesions.Conclusions: Dermoscopy is an applicable diagnostic tool for the diagnosis of cutaneous vascular anomalies. It is necessary to take into account the age stage and lesion location when we diagnose CA using dermoscopy.


Author(s):  
XIAOWEN YIN ◽  
XIAOMIN HU ◽  
TONG LI ◽  
JIAYAO MA

Ring stent implantation has been widely used to treat coarctation of the aorta (CoA) as an alternative to surgery. Currently adopted stents with uniform geometry may cause uneven stress distribution and high stress concentration in curved vessels, leading to in-stent restenosis (ISR). Inspired by functional graded material, here we propose a new ring-and-link stent, which has graded geometry in order to achieve a reduced peak stress when deployed in curved arteries. Numerical simulation of a single ring of the graded stent indicated that by varying the circumferential spacing of wave crest, the maximum stress exerted on the artery was reduced by as much as 27.86% in comparison with the uniform one. The effects of stent geometric parameters and artery curvature were also obtained through a parametric study. Finally, a whole stent was studied to verify the design, and a maximum stress reduction by 31.96% was achieved. In summary, the proposed graded ring stent shows great potential in clinical applications to reduce the risk of ISR.


2020 ◽  
Vol 15 (3) ◽  
pp. 117-125
Author(s):  
Jung-soo Park ◽  
Hyo Sung Kwak ◽  
Jin-Woo Kim

Purpose: Four key bench-top tests, including trackability, conformability, wall-apposition, and bending stiffness, were performed to understand the mechanical characteristics in 3 different types of stents applicable for treatment of intracranial atherosclerotic stenosis: Balloon-expandable D<sup>+</sup>Storm, Pro-Kinetic Energy, and self-expandable Wingspan stents.Materials and Methods: Trackability was assessed by measuring the tracking forces of each stent with its delivery systems. Conformability and wall apposition were quantified and analyzed using curved vessel models. A 3-point bending test was employed to evaluate bending stiffness.Results: D<sup>+</sup>Storm showed the lowest tracking forces while the conformability of the Wingspan stent was superior to that of the tested stents. Pro-Kinetic Energy and D<sup>+</sup>Storm had better wall apposition in curved vessels than the Wingspan stent. Bending stiffness of the Wingspan stent was notably lower, whereas no significant differences were found between D<sup>+</sup>Storm and Energy. Pro-Kinetic Energy and D<sup>+</sup>Storm not only indicated lower gap ratios between the struts and the vessel wall but also maintained good wall apposition even in the curved model.Conclusion: These bench-top measurements may provide clinicians with useful information in regard to selecting suitable stents for treatment of intracranial atherosclerotic stenosis.


2019 ◽  
Vol 864 ◽  
pp. 768-806 ◽  
Author(s):  
Peter Balogh ◽  
Prosenjit Bagchi

In the microcirculation, a plasma layer forms near the vessel walls that is free of red blood cells (RBCs). This region, often termed as the cell-free layer (CFL), plays important haemorheological and biophysical roles, and has been the subject of extensive research. Many previous studies have considered the CFL development in single, isolated vessels that are straight tubes or channels, as well as in isolated bifurcations and mergers. In the body, blood vessels are typically winding and sequentially bifurcate into smaller vessels or merge to form larger vessels. Because of this geometric complexity, the CFL in vivo is three-dimensional (3D) and asymmetric, unlike in fully developed flow in straight tubes. The three-dimensionality of the CFL as it develops in a vascular network, and the underlying hydrodynamic mechanisms, are not well understood. Using a high-fidelity model of cellular-scale blood flow in microvascular networks with in vivo-like topologies, we present a detailed analysis of the fully 3D and asymmetric nature of the CFL in such networks. We show that the CFL significantly varies over different aspects of the networks. Along the vessel lengths, such variations are predominantly non-monotonic, which indicates that the CFL profiles do not simply become more symmetric over the length as they would in straight vessels. We show that vessel tortuosity causes the CFL to become more asymmetric along the length. We specifically identify a curvature-induced migration of the RBCs as the underlying mechanism of increased asymmetry in curved vessels. The vascular bifurcations and mergers are also seen to change the CFL profiles, and in the majority of them the CFL becomes more asymmetric. For most bifurcations, this is generally observed to occur such that the CFL downstream narrows on the side of the vessel nearest the upstream bifurcation, and widens on the other side. The 3D aspects of such behaviour are elucidated. For many bifurcations, a discrepancy exists between the CFL in the daughter vessels, which arises from a disproportionate partitioning between the flow rate and RBC flux. For most mergers, the downstream CFL narrows in the plane of the merger, but widens away from this plane. The dominant mechanism by which such changes occur is identified as the geometric focusing of the two merging streams. To our knowledge, this work provides the first simulation-based analysis of the 3D CFL structure in complex in vivo-like microvascular networks, including the hydrodynamic origins of the observed behaviour.


Author(s):  
Игорь Гориков ◽  
Igor Gorikov ◽  
Николай Дорофиенко ◽  
Nikolay Dorofienko ◽  
Ольга Кутепова ◽  
...  

The aim of the study was to assess the architectonics of the venous bed of the fetus part of placenta from women with the exacerbation of cytomegalovirus (CMV) infection in the first trimester of pregnancy. There were examined 75 patients after the term birth, among them there were 25 seropositive women with the exacerbation of CMV infection in the first trimester of pregnancy without clinical signs of threatened miscarriage; 23 seropositive women with the exacerbation of CMV infection in the first trimester of pregnancy and clinical signs of threatened miscarriage; 27 seronegative women without threatened miscarriage. The architectonics of the venous bed of the fetus part was studied with the pressing of contrast (red lead oxide in the linseed oil) through the umbilical vein into the vessels and placenta cotyledons. The roentgen shots were done at the device RUM-20 M “Sapphire”. During the research of the venous bed of the fetus part of placenta from women with the exacerbation of CMV infection and threatened miscarriage in the first trimester of pregnancy there was identified a velamentous attachment of the umbilical cord with the segmentary narrowing and venous varices as well as with the decrease of the outer diameter of veins of preconfluent zone of the fetus part of the organ. There is an increase in the number of asymmetrically located biconfluent venous vessels, the quantity of marginally located and blindly finishing curved vessels of veins and venous roots, which does not provide the effective blood flow and leads to the ischemia of the peripheral (edge) part of placenta. This reduces the delivery of oxygen and metabolites to the fetus, is accompanied with the development of plethora, stasis, thrombosis and inflammation in veins and arteries, as well as the increase of the risk of partial non-progressive separation of normally placed placenta and its partial intimate attachment to the uterus.


2016 ◽  
Vol 9 (10) ◽  
pp. 969-973 ◽  
Author(s):  
Hideo Chihara ◽  
Akira Ishii ◽  
Takayuki Kikuchi ◽  
Hiroyuki Ikeda ◽  
Daisuke Arai ◽  
...  

BackgroundEnterprise VRD, a stent frequently used to assist coil embolization of cerebral aneurysms, has been upgraded to reduce the risk of incomplete stent apposition (ISA), a known risk factor for thromboembolic complications.ObjectiveTo compare the performances of Enterprise VRD and Enterprise VRD2 in curved vessels, and to investigate a deployment method that takes advantage of the features of Enterprise VRD2 to achieve better vessel wall apposition.Materials and methodsA silicone vascular model connected to a temperature-adjustable perfusion circuit was used. First, Enterprise VRD and Enterprise VRD2 were deployed under fluoroscopy and then ISA was evaluated as the stent cross-sectional area ratio at the curved segment of the vessel. For the measurements, each stent was deployed in vessels with different angles of curvature. Second, the incidence of ISA after insertion of Enterprise VRD2 by the ‘pushing over outer curve technique’, in which stents are deployed along the outer curve of vessels with continuous wire advancement, was compared with ‘Heller's push and pull technique’.ResultsFor all stents, the cross-sectional area ratio decreased with acute curvature of the vessel. Comparisons of the two stents showed that Enterprise VRD2 was better than Enterprise VRD in maintaining a greater cross-sectional area ratio in curved vessels. In addition, kinking with an acute curvature was also minimized with Enterprise VRD2. Furthermore, ISA was reduced using our technique with Enterprise VRD2.ConclusionsEnterprise VRD2 is superior to Enterprise VRD in reducing ISA in curved vessels and can alter ISA according to the deployment technique used.


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