Search

Synthetic MRI is a time-efficient imaging technique that provides both quantitative MRI and contrast-weighted images simultaneously. However, a rather long single scan time can be challenging for children.To evaluate the clinical feasibility of time-saving synthetic MRI protocols adjusted for echo train length and receiver bandwidth in pediatric neuroimaging based on image quality assessment and quantitative data analysis.In total, we included 33 children ages 1.6-17.4 years who underwent synthetic MRI using three sets of echo train length and receiver bandwidth combinations (echo train length [E]12-bandwidth [B in KHz]22, E16-B22 and E16-B83) at 3 T. The image quality and lesion conspicuity of synthetic contrast-weighted images were compared between the suggested protocol (E12-B22) and adjusted protocols (E16-B22 and E16-B83). We also compared tissue values (T1, T2, proton-density values) and brain volumetry.For the E16-B83 combination, image quality was sufficient except for 15.2% of T1-W and 3% of T2-W fluid-attenuated inversion recovery (FLAIR) images, with remarkable scan time reduction (up to 35%). The E16-B22 combination demonstrated a comparable image quality to E12-B22 (Pgt;0.05) with a scan time reduction of up to 8%. There were no significant differences in lesion conspicuity among the three protocols (Pgt;0.05). Tissue value measurements and brain tissue volumes obtained with the E12-B22 protocol and adjusted protocols showed excellent agreement and strong correlations except for gray matter volume and non-white matter/gray matter/cerebrospinal fluid volume in E12-B22 vs. E16-B83.The adjusted synthetic protocols produced image quality sufficient or comparable to that of the suggested protocol while maintaining lesion conspicuity with reduced scan time. The quantitative values were generally consistent with the suggested MRI-protocol-derived values, which supports the clinical application of adjusted protocols in pediatric neuroimaging.

Rationale: In intracranial arterial dolichoectasia (IADE) development, the feedback loop between inflammatory cytokines and macrophages involves TNF-α and NF-κB signaling pathways and leads to subsequent MMP-9 activation and extracellular matrix (ECM) degeneration. In this proof-of-concept study, melittin-loaded L-arginine-coated iron oxide nanoparticle (MeLioN) was proposed as the protective measure of IADE formation for this macrophage-mediated inflammation and ECM degeneration. Methods: IADE was created in 8-week-old C57BL/6J male mice by inducing hypertension and elastase injection into a basal cistern. Melittin was loaded on the surface of ION as a core-shell structure (hydrodynamic size, 202.4 nm; polydispersity index, 0.158). Treatment of MeLioN (2.5 mg/kg, five doses) started after the IADE induction, and the brain was harvested in the third week. In the healthy control, disease control, and MeLioN-treated group, the morphologic changes of the cerebral arterial wall were measured by diameter, thickness, and ECM composition. The expression level of MMP-9, CD68, MCP-1, TNF-α, and NF-κB was assessed from immunohistochemistry, polymerase chain reaction, and Western blot assay. Results: MeLioN prevented morphologic changes of cerebral arterial wall related to IADE formation by restoring ECM alterations and suppressing MMP-9 expression. MeLioN inhibited MCP-1 expression and reduced CD68-positive macrophage recruitments into cerebral arterial walls. MeLioN blocked TNF-α activation and NF-κB signaling pathway. In the Sylvian cistern, co-localization was found between the CD68-positive macrophage infiltrations and the MeLioN distributions detected on Prussian Blue and T2* gradient-echo MRI, suggesting the role of macrophage harboring MeLioN. Conclusions: The macrophage infiltration into the arterial wall plays a critical role in the MMP-9 secretion. MeLioN, designed for ION-mediated melittin delivery, effectively prevents IADE formation by suppressing macrophage-mediated inflammations and MMP activity. MeLioN can be a promising strategy preventing IADE development in high-risk populations.

Considering the crosstalk between the flow and vessel wall, hemodynamic assessment of the neurovascular system may offer a well-integrated solution for both diagnosis and management by adding prognostic significance to the standard CT/MR angiography. 4D flow MRI or time-resolved 3D velocity-encoded phase-contrast MRI has long been promising for the hemodynamic evaluation of the great vessels, but challenged in clinical studies for assessing intracranial vessels with small diameter due to long scan times and low spatiotemporal resolution. Current accelerated MRI techniques, including parallel imaging with compressed sensing and radial k-space undersampling acquisitions, have decreased scan times dramatically while preserving spatial resolution. 4D flow MRI visualized and measured 3D complex flow of neurovascular diseases such as aneurysm, arteriovenous shunts, and atherosclerotic stenosis using parameters including flow volume, velocity vector, pressure gradients, and wall shear stress. In addition to the noninvasiveness of the phase contrast technique and retrospective flow measurement through the wanted windows of the analysis plane, 4D flow MRI has shown several advantages over Doppler ultrasound or computational fluid dynamics. The evaluation of the flow status and vessel wall can be performed simultaneously in the same imaging modality. This article is an overview of the recent advances in neurovascular 4D flow MRI techniques and their potential clinical applications in neurovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

The aim of this study was to compare the performance of a deep-learning convolutional neural network (Faster R-CNN) model to detect imaging findings suggestive of idiopathic Parkinson’s disease (PD) based on [18F]FP-CIT PET maximum intensity projection (MIP) images versus that of nuclear medicine (NM) physicians. The anteroposterior MIP images of the [18F]FP-CIT PET scan of 527 patients were classified as having PD (139 images) or non-PD (388 images) patterns according to the final diagnosis. Non-PD patterns were classified as overall-normal (ONL, 365 images) and vascular parkinsonism with definite defects or prominently decreased dopamine transporter binding (dVP, 23 images) patterns. Faster R-CNN was trained on 120 PD, 320 ONL, and 16 dVP pattern images and tested on the 19 PD, 45 ONL, and seven dVP patterns images. The performance of the Faster R-CNN and three NM physicians was assessed using receiver operating characteristics curve analysis. The difference in performance was assessed using Cochran’s Q test, and the inter-rater reliability was calculated. Faster R-CNN showed high accuracy in differentiating PD from non-PD patterns and also from dVP patterns, with results comparable to those of NM physicians. There were no significant differences in the area under the curve and performance. The inter-rater reliability among Faster R-CNN and NM physicians showed substantial to almost perfect agreement. The deep-learning model accurately differentiated PD from non-PD patterns on MIP images of [18F]FP-CIT PET, and its performance was comparable to that of NM physicians.

The aim of this study was to analyze the characteristics of time-velocity curve acquired by phase-contrast magnetic resonance imaging (PC-MRI) using an in-vitro flow model as a reference for hemodynamic studies. The time- velocity curves of the PC-MRI were compared with Doppler ultrasonography (US) and also compared with those obtained in the electromagnetic flowmeter. The correlation between techniques was analyzed using an electromagnetic flowmeter as a reference standard; the maximum, minimum, and average velocities, full-width at half-maximum (FWHM), and ascending gradient (AG) were measured from time-velocity curves. The correlations between an electromagnetic flowmeter and the respective measurement technique for the PC-MRI and Doppler US were found to be high (mean R2 > 0.9, p

High-aspect-ratio microstructures (HARMS) of polyimides have many applications, such as components of microelectromechanical systems and X-ray gratings. This study demonstrates the fabrication of HARMS with vertical and smooth sidewalls in a thick, soluble block-copolymer polyimide (SBCP) film by an UV-assisted thermal imprint process. A preheating condition was controlled as a parameter that dominated the imprint pattern fidelity. After investigating a proper prebaking condition, patterns with a width of 3.4 μm and a height of 35.1 μm with a high-aspect ratio of 10 were successfully structured in an SBCP film that has a thickness of approximately a hundred micrometers. The process has potential as a low-cost fine pattern fabrication process for polyimide-based polymers.

This study aimed to explore the myelin volume change in patients with mild traumatic brain injury (mTBI) with post-concussion syndrome (PCS) using a multidynamic multiecho (MDME) sequence and automatic whole-brain segmentation.Forty-one consecutive mTBI patients with PCS and 29 controls, who had undergone MRI including the MDME sequence between October 2016 and April 2018, were included. Myelin volume fraction (MVF) maps were derived from the MDME sequence. After three dimensional T1-based brain segmentation, the average MVF was analyzed at the bilateral cerebral white matter (WM), bilateral cerebral gray matter (GM), corpus callosum, and brainstem. The Mann-Whitney U-test was performed to compare MVF and myelin volume between patients with mTBI and controls. Myelin volume was correlated with neuropsychological test scores using the Spearman rank correlation test.The average MVF at the bilateral cerebral WM was lower in mTBI patients with PCS (median [interquartile range], 25.2% [22.6%-26.4%]) than that in controls (26.8% [25.6%-27.8%]) (MVF quantified from the MDME sequence was decreased at the bilateral cerebral WM in mTBI patients with PCS. The total myelin volumes at the corpus callosum and brainstem were decreased in mTBI patients with PCS due to atrophic changes.

Hyperlipidemia is a chronic disorder that plays an important role in the development of cardiovascular diseases, type II diabetes, atherosclerosis, hypertension, and non-alcoholic fatty liver disease. Hyperlipidemias have created a worldwide health crisis and impose a substantial burden not only on personal health but also on societies and economies. Transcription factors in the sterol regulatory element binding protein (SREBP) family are key regulators of the lipogenic genes in the liver. SREBPs regulate lipid homeostasis by controlling the expression of a range of enzymes required for the synthesis of endogenous cholesterol, fatty acids, triacylglycerol, and phospholipids. Thereby, SREBPs have been considered as targets for the treatment of metabolic diseases. The aim of this study was to investigate the beneficial functions and the possible underlying molecular mechanisms of SREBP decoy ODN, which is a novel inhibitor of SREBPs, in high-fat diet (HFD)-fed hyperlipidemic mice. Our studies using HFD-induced hyperlipidemia animal model revealed that SREBB decoy ODN inhibited the increased expression of fatty acid synthetic pathway, such as SREBP-1c, FAS, SCD-1, ACC1, and HMGCR. In addition, SREBP decoy ODN decreased pro-inflammatory cytokines, including TNF-&alpha, IL-1&beta, IL-8, and IL-6 expression. These results suggest that SREBP decoy ODN exerts its anti-hyperlipidemia effects in HFD-induced hyperlipidemia mice by regulating their lipid metabolism and inhibiting lipogenesis through inactivation of the SREPB pathway.

Objectives To investigate the safety and tolerability of gadobutrol at the recommended dose in patients requiring contrast-enhanced magnetic resonance imaging/angiography (MRI/MRA) in the routine setting. Methods GARDIAN prospectively enrolled 23,708 patients undergoing routine gadobutrol-enhanced MRI/MRA for approved indications at 272 study centres in Europe, Asia, North America, and Africa and monitored for adverse events. Results Median gadobutrol dose was 0.11 mmol/kg body weight. The overall incidence of adverse drug reactions (ADRs) was 0.7 % (n = 170 patients), with similar incidences in patients with renal impairment or cardiac disease, from different geographic regions and in different gadobutrol dose groups. Patients at risk for contrast media reaction had an ADR incidence of 2.5 %. Five patients (0.02 %) experienced serious adverse events, four were drug-related. One patient experienced a fatal anaphylactoid shock, assessed to be related to injection of gadobutrol. The contrast quality of gadobutrol-enhanced images was rated by treating physicians as good or excellent in 97 % cases, with similar ratings in all patient subgroups and indications. Conclusions The GARDIAN study shows that gadobutrol at the recommended dose is well tolerated across a large, diverse patient population. Key points • Gadobutrol at recommended dose shows low rates of adverse drug reactions • Gadobutrol demonstrates a uniform safety profile across diverse patient groups • Gadobutrol provides excellent contrast quality in routine practice

Background and Purpose: The signal information per voxels of magnetic resonance imaging (MRI) for vessel wall could reflect the pathologic features of atherosclerotic vessels. The aim of this study is to evaluate the usefulness of magnetic resonance voxel-based histogram (VBH) of atherosclerotic basilar artery in patients with isolated pontine infarctions (PIs). Materials and Methods: Wall and lumen of basilar artery were segmented from high resolution MR of 42 patients with isolated PI and 10 normal volunteers. VBHs were obtained after normalization by dividing the intensity of segmented wall with the intensity of non-infarcted area of pons. The variables of VBH included area (A), mean signal intensity (SI), standard deviation (SD), kurtosis (K), and skewness (SK) and area stenosis [AS; Awall/(Awall + Alumen)] were compared according to the MRI-modified American Heart Association (AHA) atherosclerotic plaque schema, and between the subgroups of PI (lacunar: LPI and paramedian: PPI). Results: According to the MRI-modified AHA atherosclerotic plaque schema, Awall/T1 (mean area of wall on T1-weighted MRI), SIwall/T1, SDwall/T1, SKwall/T1, Kwall/T1, Alumen/T1, and AST1 showed statistical differences. AHA IV–VII showed higher Awall/T1, SIwall/T1, and AST1 than normal control. PPI showed statistical differences in Awall/T1, SIwall/T1, SK wall/T1, and Awall/T2 than those of normal control after post hoc test, whereas LPI in Awall/T1 and Awall/T2 (P < 0.05, Kruskal-Wallis test, Dunnett T3 procedure). Conclusions: VBH analysis can provide the quantitative information with regard to volume as well as composition of the atherosclerotic plaque in the basilar artery. The difference in patterns of VBH might be further useful in characterizing PIs with presumably different pathogenesis.

Atherosclerosis arises when injury to the arterial wall induces an inflammatory cascade that is sustained by a complex network of cytokines, together with accumulation of lipids and fibrous material. Inflammatory cascades involve leukocyte adherence and chemotaxis, which are coordinated by the local secretion of adhesion molecules, chemotactic factors, and cytokines. Transcription factors are critical to the integration of the various steps of the cascade response to mediators of vascular injury, and are induced in a stimulus-dependent and cell-type-specific manner. Several small-nucleic-acid-based therapeutic strategies have recently been developed to target transcription factors: antisense oligodeoxynucleotides, RNA interference, microRNA, and decoy oligodeoxynucleotides. The aim of this review was to provide an overview of these particular targeted therapeutic strategies, toward regulation of the vascular inflammation, remodeling and fibrosis associated with atherosclerosis.

Display Omitted The resin filling of large patterns of UV nanoimprinting was investigated.The filling time increased proportionally to the area of the pattern cavity.Filling mainly proceeds because of the capillary pressure of the resin.We derived a modified Stefan's formula of considering the capillary filling. Using a full-area monitoring system based on dark-field illumination, we investigated the use of resin filling of UV nanoimprints to fabricate large checker patterns with edge lengths up to 400µm at thin resin layers (

Ultraviolet nanoimprint lithography (UV-NIL) is a recently developed technology that allows low-cost nanofabrication. Bubble-free filling needs to be achieved to realize high-throughput mass production in UV-NIL. Although bubble-free filling can be accomplished by performing UV-NIL under vacuum, nonvacuum processes can lower equipment and operation costs. Polydimethylsiloxane (PDMS) is known as a gas transmittable materials due to its molecular feature and used for flexible molds in UV-NIL. In this work, we investigated the effects of UV-NIL using PDMS mold for filling behaviors and mold release force in different atmosphere. Bubble-free filling of UV-NIL was successfully demonstrated in air, and 1, 1, 1, 3, 3-pentafluoropropane (PFP) gas atmosphere. The average release force following UV-NIL in PFP was 8.14 N, which is 52 % smaller than that following UV-NIL in air. Fine nanopatterns with 250 nm width were successfully fabricated by UV-NIL in PFP atmosphere without any defects.

and quantitative evidence for whether endovascular occlusion would remove the shunts connected to extradural venous drainage alone, or further resolve the disturbance of cerebral venous flow. It is not known how cerebral vessels would change in the long-term as a result of obstructing this shunt flow, or how the clinical symptoms are related to the haemodynamic changes in the rare cases of spontaneous regression. The understanding of the pathophysiology of CCF can be enhanced by correlating the clinical symptoms and MRI findings during a long observational period. Velocity-encoded magnetic resonance imaging (VENCMRI) has shown excellent diagnostic accuracy and reliability for the measurement of the flow volumes (FVs) in cerebral vessels [12]. Furthermore, VENC-MRI does not require contrast medium administration or invasive catheterization, and is considered a safe and appropriate followup imaging technique [13]. However, this tool has never been used for quantifying the shunt volume and cerebral circulation related to CCF. A case in which VENC-MRI was used to measure the shunt volume of and FVs in the cerebral vessels in a direct CCF patient is presented herein. The temporal changes during spontaneous regression are demonstrated, and the relationships between the patient’s clinical symptoms and the measured cerebral haemodynamics are discussed.

The cerebral protection device (CPD) itself may cause complications, including locking between the CPD and other devices, that may result in catastrophic outcomes requiring surgical removal of these locked devices. We describe a case of locking between a CPD and the stent-delivering catheter during carotid artery stenting, which was safely rescued by endovascular retrieval. The mechanism underlying locking with the CPD as well as preventive actions and maneuvers for rescuing the situation are discussed.

This paper describes a simple fabrication process of fine groove structures for quartz molds used in UV nanoimprint lithography. Grooves that are finer than the ''spaces'' in line/space resist patterns can be obtained on a quartz substrate with the aid of thin Cr layer and a dry etching process using CHF"3. The main cause of the groove width narrowing is deposition of fluorocarbon polymer. By changing etching conditions, a large amount of space narrowing is realized. Grooves with widths of 18nm and 62nm were successfully obtained from 85-nm and 200-nm wide space resist patterns, respectively.

We present our experience of flow control with the aid of a circular compression device (CCD) for embolization of scalp arteriovenous fistulae (sAVFs). A 21-year-old female presented with a pulsating scalp mass with sAVFs fed by the superficial temporal arteries. A CCD with a beveled circular handle and concentric hole was used to treat the condition. After the CCD was compressed over the area of the fistulae, the fistulae were punctured and blood regurgitation was assured. While maintaining flow stasis within the boundary of the CCD and loading heparinized dextrose-saline solution, a 50% mixture of N-butyl-2-cyanoacrylate and Lipiodol was applied during the compression, which was sustained for 1-2 minutes. Finally, the sAVFs were almost completely occluded without complications. Our designed CCD was effective for flow control, and direct-puncture embolization of N-butyl-2-cyanoacrylate during flow control using the CCD was safe and effective for the treatment of sAVFs.

There have been few reports on the endovascular treatment of aneurysms arising from A1 due to their rarity. We report the angiographic results, clinical outcomes, and technical aspects of endovascular treatment for 13 A1 aneurysms in 12 patients. From January 2002 to November 2007, 12 patients (9 females and 3 males) with 13 A1 aneurysms underwent endovascular treatment. Three of these patients presented with subarachnoid hemorrhage, and 10 unruptured aneurysms were detected in 9 patients. All of the aneurysms were successfully treated with coil embolization. Most of the aneurysms projected posteriorly (61.5%) and were located in the proximal A1 segment (69.2%). Procedural, clinical, and radiological follow-up data were reviewed. Procedure-related complications occurred in 3 patients (25%) and included 1 non-leaking aneurysmal perforation and 2 thromboembolic events; none of them were clinically significant. No bleeding or rebleeding occurred during the follow-up period in this cohort of patients. Endovascular coil embolization is an effective treatment modality for A1 aneurysms. Tailored microcatheter shaping according to aneurysm projection and location is necessary. Long-term follow-up studies involving a larger number of patients and further comparisons with surgical data are needed.

This study explored a simplified micro-scale Cu damascene process based on UV-assisted thermal imprinting of SU-8 to investigate its process merits and potential defects that may occur during and after processing. For comparative study, arbitrary electrical circuits composed of Cu wiring structures with widths ranging from 10@mm to 1mm were developed in SU-8/Si patterned by UV-assisted thermal imprinting and in oxidized Si samples prepared by reactive ion etching (RIE) followed by thermal oxidation. The imprint-based approach could lower process cycles, equipment cost, and etching gas use, whereas it induced a higher residual stress and more delamination defects. The process studied here are expected to be applied to fabricate micro-scale Cu structures, such as coils, antennas, electrical circuits, and wiring and connecting lines if further enhancements of the adhesion ability between layers and the design of pattern fields in a mold are accomplished.

In this work we demonstrate the hot-embossing process under different forming conditions such as forming temperature, load, and holding time in pressing, in order to determine the suitable conditions required for linear patterning on polymer plates (PMMA and PC). Results showed that the replicated pattern depth increased in proportion to an increase in the forming temperature, load, and time. The reduction of the workpiece thickness increased according to the holding time in the pressing process. In the process of time, the reduction ratio of the workpiece thickness decreased due to the surface area increment of the workpiece, while the pressure on the workpiece declined. In order to reduce the bulging ratio we introduced a temperature difference between the upper and the lower punch.

We describe an extremely rare case of bilateral intrathyroidal branchial cleft cysts. A 2-day-old male neonate presented with intermittent tachypnea, dyspnea, and a palpable neck mass. Cervical ultrasonography and computerized tomography scan demonstrated a right-sided 3 x 3-cm cystic mass and a left sided 4.5 x 4-cm cystic mass, thought to be originating in the thyroid gland. The right-sided cyst decreased in size after OK-432 sclerotherapy. The left-sided cyst showed little response to 2 attempts of OK-432 sclerotherapy. Surgical removal of the left-sided cyst was done because of intermittent airway problems. The cystic mass was thought to be an intrathyroidal lesion. Microscopically, the cyst was lined by nonkeratinized squamous epithelium and respiratory epithelium. Lymphocyte infiltration was found in the subepithelial layer. The patient is currently doing well 12 months later with no evidence of recurrence.

Patterning techniques of Al micro/nano-structures become more and more critical as optical components and microelectronic devices continue to be scaled down. In this work, we fabricated gap-filled Al lines in SiO"2/Si masters by using the direct thermal imprint of molten Al. As a result, gap-filled Al lines with width ranging from 0.25 to 20@mm and depth ranging from 6 to 127@mm could be achieved without any further processing step such as CVD and PVD. The process studied here has shown the possibility to extend trench filling capability to 0.25@mm structures with 24:1 aspect ratio, which are difficult to be obtained by other conventional Al metallization methods.