Modified respiratory-triggered SPACE sequences for magnetic resonance cholangiopancreatography.

Background: Respiratory-triggered (RT) and breath-hold are the most common acquisition modalities for magnetic resonance cholangiopancreatography (MRCP). The present study compared the three different acquisition modalities for optimizing the use of MRCP in patients with diseases of the pancreatic and biliary systems. Materials and methods: Three MRCP acquisition modalities were used in this study: conventional respiratory-triggered sampling perfection with application-optimized contrasts using different flip evolutions (RT-SPACE), modified RT-SPACE, and breath-hold (BH)-SPACE. Fifty-eight patients with clinically suspected pancreatic and biliary system disease were included. All image data were acquired on a 1.5 T MR. Scan time and image quality were compared between the three acquisition modalities. Friedman test, which was followed by post-hoc analysis, was performed among triple-scan protocol. Results: There was a significant difference in the mean acquisition time among conventional RT-SPACE, modified RT-SPACE, and BH-SPACE (167.41±32.11 seconds vs 50.84±73.78 seconds vs 18.00 seconds, P <0.001). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also significantly different among the three groups (P <0.001). The SNR and CNR were higher in the RT-SPACE group than in the BH-SPACE group (P <0.05). However, there were no statistically significant differences (P >0.05) among the 3 groups regarding quality of overall image, image clarity, background inhibition, and visualization of the pancreatic and biliary system. Conclusions: MRCP acquisition with the modified RT-SPACE sequence greatly shortens the acquisition time with comparable quality images. The MRCP acquisition modality could be designed based on the patient's situation to improve the examination pass rate and obtain excellent images for diagnosis.

DTI-ALPS: An MR biomarker for motor dysfunction in patients with subacute ischemic stroke.

Purpose: Brain glymphatic dysfunction is involved in the pathologic process of acute ischemic stroke (IS). The relationship between brain glymphatic activity and dysfunction in subacute IS has not been fully elucidated. Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index was used in this study to explore whether glymphatic activity was related to motor dysfunction in subacute IS patients. Methods: Twenty-six subacute IS patients with a single lesion in the left subcortical region and 32 healthy controls (HCs) were recruited in this study. The DTI-ALPS index and DTI metrics (fractional anisotropy, FA, and mean diffusivity, MD) were compared within and between groups. Spearman's and Pearson's partial correlation analyses were performed to analyze the relationships of the DTI-ALPS index with Fugl-Meyer assessment (FMA) scores and with corticospinal tract (CST) integrity in the IS group, respectively. Results: Six IS patients and two HCs were excluded. The left DTI-ALPS index of the IS group was significantly lower than that of the HC group (t = -3.02, p = 0.004). In the IS group, a positive correlation between the left DTI-ALPS index and the simple Fugl-Meyer motor function score (ρ = 0.52, p = 0.019) and a significant negative correlation between the left DTI-ALPS index and the FA (R = -0.55, p = 0.023) and MD (R = -0.48, p = 0.032) values of the right CST were found. Conclusions: Glymphatic dysfunction is involved in subacute IS. DTI-ALPS could be a potential magnetic resonance (MR) biomarker of motor dysfunction in subacute IS patients. These findings contribute to a better understanding of the pathophysiological mechanisms of IS and provide a new target for alternative treatments for IS.

Quantitative susceptibility mapping to evaluate brain iron deposition and its correlation with physiological parameters in hypertensive patients.

BACKGROUND: Regional excessive iron overload is pernicious to motor functions and cognitive functioning of the brain. The aim of this research was to utilize quantitative susceptibility mapping (QSM) to inspect brain iron accumulation in patients with hypertension (HP), and to evaluate whether it is correlated with physiological parameters. METHODS: Thirty-one HP and 31 age- and sex-matched healthy controls (HC) were included. All participants underwent brain magnetic resonance imaging (MRI), and QSM data were obtained. Differences in brain iron deposition in deep gray matter nuclei of participants were compared between HP and HC. The correlations between iron deposition, body mass index (BMI), maximum systolic blood pressure (SBP), and diastolic blood pressure (DBP) were analyzed. RESULTS: The HP group showed increased susceptibility values in the caudate nucleus (CA), putamen (PU), globus pallidus (GP), and dorsal thalamus (TH), compared with the HC group. There was a significant positive correlation between BMI and the susceptibility values in the dentate nucleus (DN); the maximum SBP and DBP were positively correlated with magnetic susceptibility of the CA, PU, GP, and TH, respectively. CONCLUSIONS: These results are indicative of the role of overload brain iron in deep brain gray matter nuclei in HP and suggest that HP is associated with excess brain iron in certain deep gray matter regions.

Fe3O4 nanobelts: one-pot and template-free synthesis, magnetic property, and application for lithium storage.

We report on the synthesis of Fe(3)O(4) nanobelts with good magnetic properties and lithium storage performances by using a one-pot and template-free hydrothermal method with Na(2)CO(3) and FeCl(2) as the reactants. By controlling the amount of Na(2)CO(3), we obtained pure Fe(3)O(4) nanobelts with widths of 0.1-2 µm, thicknesses of about 10 nm and lengths of 20-30 µm, showing a high aspect ratio. XRD and SAED patterns of the obtained sample demonstrated that the Fe(3)O(4) nanobelts were well crystallized. Nitrogen adsorption/desorption measurements showed that Fe(3)O(4) nanobelts manifested a BET surface area of 25.04 m(2) g(-1). Further experiments demonstrated that the amount of Na(2)CO(3) played an important role in controlling both the morphologies and crystal structures of the products. The formation mechanism of Fe(3)O(4) nanobelts was also studied. More importantly, we found that the Fe(3)O(4) nanobelts showed magnetic properties with a magnetic saturation value of 77.0 emu g(-1) and lithium storage performances with a high initial discharge capacity of 1090 mAh g(-1) at a current rate of 500 mA g(-1), and a reversible capacity of 404 mAh g(-1) retained after 60 charge/discharge cycles. These results suggest that the Fe(3)O(4) nanobelts might be promising for magnetic and lithium battery applications.

Carbon-decorated single-crystalline Ni2P nanotubes derived from ni nanowire templates: a high-performance material for Li-ion batteries.

Single-crystalline Ni(2)P nanotubes (NTs) were facilely synthesized by using a Ni nanowire template. The mechanism for the formation of the tubular structures was related to the nanoscale Kirkendall effect. These NTs exhibited a core/shell structure with an amorphous carbon layer that was grown in situ by employing oleylamine as a capping agent. Galvanostatic charge/discharge measurements indicated that these Ni(2)P/C NTs exhibited superior high-rate capability and good cycling stability. There was still about 310 mA h g(-1) retained after 100 cycles at a rate of 5 C. Importantly, the tubular nanostructures and the single-crystalline nature of the Ni(2)P NTs were also preserved after prolonged cycling at a relatively high rate. These improvements were attributed to the stable nanotubular structure of Ni(2)P and the carbon shell, which enhanced the conductivity of Ni(2)P, suppressed the aggregation of active particles, and increased the electrode stability during cycling.