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TTo perform three-dimensional (3D) quantitative TProspective.Eight healthy subjects and 20 patients with symptomatic carotid atherosclerosis.3 T, SQUMA imaging TSQUMA was acquired in all subjects and multi-contrast images were acquired in healthy subjects. TPaired t or Wilcoxon signed-rank test, independent t or Mann-Whitney U test, area under the receiver operating characteristic curve (AUC), intraclass correlation coefficients, and Bland-Altman plots. Statistically significant level, P 0.05.There were no significant differences in LA (P = 0.340), WA (P = 0.317), MeanWT (P = 0.088), and NWI (P = 0.091) of carotid arteries between SQUMA and multi-contrast vessel wall images. The values of TCarotid MR 3D quantitative multi-parametric imaging of SQUMA enables acquisition of T2 TECHNICAL EFFICACY: Stage 2.

The association between haemoglobin A1c (HbA1c) and cerebral microbleeds (CMBs) remains unclear. We aimed to investigate the association between HbA1c and CMBs in community-based individuals without stroke or transient ischaemic attack (TIA) and whether the association differs between individuals with and without diabetes mellitus (DM).All individuals were recruited from a community in Beijing, China, from January 2015 to September 2019. All individuals completed a questionnaire and underwent blood tests and brain magnetic resonance imaging. A susceptibility-weighted imaging sequence was acquired to detect CMBs, which were defined as small, round and low-signal lesions with10 mm diameter. The association between HbA1c and CMBs was analysed using multivariable logistic regression adjusted for demographics, medical history and blood sample test results. Subgroup analyses stratified by history of DM were performed.Of 544 recruited individuals, 119 (21.88%) had CMBs. HbA1c was independently associated with CMBs (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.03-2.22). In 87 individuals with DM, multivariable logistic analysis showed that HbA1c was significantly associated with CMBs (OR, 1.67; 95% CI, 1.04-2.69), whereas in individuals without DM, no significant association was observed between HbA1c and CMBs (OR, 1.07; 95% CI, 0.50-2.30).HbA1c was associated with CMBs in individuals without stroke or TIA, particularly in individuals with DM, suggesting that the status of glycaemic control warrants attention for the prevention of CMBs. It would be beneficial to manage HbA1c specifically to control the risk of CMBs, especially in individuals with DM.

To propose a free-breathing simultaneous multi-delay arterial spin labeling (ASL) and TThe proposed saturated multi-delay renal arterial spin labeling (SAMURAI) sequence used flow-sensitive alternating inversion recovery (FAIR) preparation, followed by acquisition of 9 images with Look-Locker spoiled gradient recalled echo (SPGR). Pre-saturation at the imaging slice was used to achieve saturation-based TThe proposed SAMURAI technique can provide accurate TThe proposed SAMURAI technique is feasible and repeatable for simultaneously quantifying T

White matter hyperintensity (WMH) is prevalent in elderly populations. Ischemia is characterized by a decline in cerebral blood flow (CBF) and may play a key role in the pathogenesis of WMH. However, the association between CBF reduction and WMH progression remains controversial. This study aimed to investigate the association between CBF and the progression of WMH at a 2-year follow-up of community-based, asymptomatic adults in a longitudinal cohort study across the lifespan.Asymptomatic adults who participated in a community-based study were recruited and underwent brain structural and perfusion magnetic resonance imaging (MRI) at baseline and at a 2-year follow-up visit. The CBF was measured on pseudo-continuous arterial spin-labeling (pCASL) MRI. The WMH was evaluated on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) images. Tissue segmentation was conducted on T1-weighted (T1W) images to derive binary masks of gray matter and normal-appearing white matter. Linear mixed effect models were conducted to analyze the cross-sectional and longitudinal associations between CBF and WMH.A total of 229 adults (mean age 57.3±12.6 years; 94 males) were enrolled at baseline, among whom 84 participants (mean age 54.1±11.9 years; 41 males) completed a follow-up visit with a mean time interval of 2.77±0.44 years. At baseline, there was a decreasing trend in gray matter (GM) CBF with an increase of WMH burden (P=0.063), but this association was attenuated after adjusting for age (P=0.362). In the longitudinal analysis, baseline WMH volume was significantly associated with the reduction of perfusion in GM [coefficient =-1.96, 95% confidence interval (CI): -3.25 to -0.67; P=0.004] and normal appearing white matter (coefficient =-0.99, 95% CI: -1.66 to -0.31; P=0.005) during follow-up. On the contrary, neither baseline CBF in GM (P=0.888) nor normal appearing white matter (P=0.850) was associated with WMH progression. In addition, CBF changes within WMH were significantly associated with both baseline (coefficient =-0.014, 95% CI: -0.025 to -0.003; P=0.017) and progression (coefficient =-1.01, 95% CI: -1.81 to -0.20; P=0.015) of WMH volume.A WMH burden was not found to be directly associated with cortex perfusion at baseline due to the effects of age on both CBF and WMH. However, baseline WMH volume could predict the reduction of perfusion.

Many diseases can simultaneously involve renal arteries and the adjacent abdominal aorta. This study proposed a free-breathing three-dimensional (3D) isotropic-resolution magnetic resonance sequence for simultaneous vessel wall imaging (VWI) of bilateral renal arteries and adjacent abdominal aorta.A respiratory-triggered isotropic-resolution sequence that combined the improved motion-sensitized driven-equilibrium (iMSDE) preparation with the spoiled gradient recalled (SPGR) readout (iMSDE-SPGR) was proposed for simultaneous VWI of renal arteries and abdominal aorta. The proposed iMSDE-SPGR sequence was optimized by positioning spatial saturation pulses (i.e., REST slabs) elaborately to further alleviate respiratory and gastrointestinal motion artifacts and selecting appropriate first-order gradient moment (mThe proposed iMSDE-SPGR sequence was feasible for simultaneous VWI both in the healthy subjects and the patients. The sequence showed good to excellent inter-observer (ICC: 0.615-0.999), excellent intra-observer (ICC: 0.801-0.998), and scan-rescan (ICC: 0.768-0.998) reproducibility in measuring morphology, SNR, and CNR. There were no significant differences in SNR, CNR, and morphology measurements between observers and between scans (all p 0.05). Bland-Altman plots showed small bias in assessing SNR, CNR, and morphology.The proposed free-breathing 3D isotropic-resolution iMSDE-SPGR technique is feasible and reproducible for simultaneous VWI of bilateral renal arteries and adjacent abdominal aorta.

Hemodynamic patterns play key roles in progression of carotid vulnerable plaques. However, most of previous studies utilized maximum or averaged value of hemodynamic measurements which is not an ideal representative of hemodynamic patterns. This study aimed to investigate the association of slice-based and time-specific hemodynamic measurements with carotid vulnerable plaque using magnetic resonance (MR) vessel wall imaging and histology.Thirty-two patients (mean age: 63.9±8.1 years; 25 males) with carotid atherosclerotic stenosis (≥50% stenosis) referred to carotid endarterectomy were recruited and underwent MR vessel wall imaging. Carotid plaque burden was evaluated on MR images and vulnerable plaque features including calcification, lipid-rich necrotic core, and intra-plaque hemorrhage (IPH) were identified by histology. The slice-based and time-specific hemodynamic measurements were extracted from computational fluid dynamics simulation of 3D carotid arterial model. Correlation coefficients between hemodynamic measurements and carotid plaque features were calculated and the logistic regressions with generalized estimating equation (GEE) were conducted. The value in discriminating carotid vulnerable plaque features was determined by receiver-operating-characteristic analysis.Of 102 MR-histology matched slices from 32 patients, time-averaged wall shear stress (TAWSS) (r=0.263, p=0.008), oscillatory shear index (OSI) (r=-0.374, p0.001), and peakWSS (r=0.232, p=0.019) were significantly associated with carotid IPH. The logistic regression with GEE revealed that peakWSS (OR, 1.206; 95% CI, 1.026-1.418; p, 0.023) and TAWSS (OR, 0.364, 95% CI, 0.138-0.959; p, 0.041) were significantly associated with presence of IPH after adjusting for age and BMI. In discriminating carotid IPH, the AUC of TAWSS, OSI, combined TAWSS with maximum wall thickness (MWT) and combined OSI with MWT was 0.656, 0.722, 0.761, and 0.764, respectively.Slice-based and time-specific hemodynamic characteristics could effectively discriminate carotid IPH. Combination of hemodynamic measurements with carotid plaque burden might be a stronger indicator for carotid vulnerable plaque features than each measurement alone.

Image registration is one of the most important processes for the generation of remote sensing image mosaics. This paper focuses on the special problems related to remote sensing data registration, and multi-temporal data mosaic applications in the domain of forestry. It proposes an image registration method based on hierarchical convolutional features, and applies it to improve the efficiency of large scale forestry image mosaic generation. This method uses a deep learning architecture to adaptively obtain image features from deep convolutional neural networks. The features derived from different images at different depth are sent to a correlation filter to compute the similarity between them; then the locations of the feature points are computed precisely. Based on this method, we study forestry image registration and the mosaic framework. We apply our approach to remote sensing images under different weather and seasonal conditions, and compare the results with those generated using the traditional SIFT image mosaic method. The experimental result shows that our method can detect and match the image feature points with significant spectral difference, and effectively extract feature points to generate accurate image registration and mosaic results. This demonstrates the effectiveness and robustness of the proposed approach.

We compared plaque characteristics between symptomatic and asymptomatic sides in patients with bilateral carotid vulnerable plaques using magnetic resonance imaging (MRI). Participants (n = 67; mean age: 65.8 ± 7.7 years, 61 males) with bilateral carotid vulnerable plaques were included. Vulnerable plaques were characterized by intraplaque hemorrhage (IPH), large lipid-rich necrotic core (LRNC), or fibrous cap rupture (FCR) on MRI. Symptomatic vulnerable plaques showed greater plaque burden, LRNC volume (median: 221.4 vs 134.8 mm3, P = .003), IPH volume (median: 32.2 vs 22.5 mm3, P = .030), maximum percentage (Max%) LRNC (median: 51.3% vs 41.8%, P = .002), Max%IPH (median: 13.4% vs 9.5%, P = .022), cumulative slices of LRNC (median: 10 vs 8, P = .005), and more juxtaluminal IPH and/or thrombus (29.9% vs 6.0%, P = .001) and FCR (37.3% vs 16.4%, P = .007) than asymptomatic ones. After adjusting for plaque burden, differences in juxtaluminal IPH and/or thrombus (odds ratio [OR]: 5.49, 95% CI: 1.61-18.75, P = .007) and FCR (OR: 2.90, 95% CI: 1.16-7.24, P = .022) between bilateral sides remained statistically significant. For patients with bilateral carotid vulnerable plaques, symptomatic plaques had greater burden, more juxtaluminal IPH and/or thrombus, and FCR compared with asymptomatic ones. The differences in juxtaluminal IPH and/or thrombus and FCR between bilateral sides were independent of plaque burden.

BackgroundTo investigate the association between hemoglobin A1c (HbA1c) and intraplaque hemorrhage (IPH) in carotid atherosclerotic plaque detected by high-resolution magnetic resonance imaging (HR-MRI) in a community-based population. MethodsIn this cross-sectional, community-based study, a total of 598 participants were recruited from May 2015 to September 2019. All participants underwent carotid artery HR-MRI. Data on demographics, medical history, and physical examinations were obtained through face-to-face interview, and fasting blood sample were collected. HbA1c was determined using high-performance liquid chromatographic analysis. Presence or absence of carotid plaque IPH was determined by HR-MRI. Multiple stepwise logistic regression analysis was performed to investigate the association between HbA1c levels and carotid plaque IPH. ResultsOf the 598 participants, 317 (53.0%) had atherosclerotic plaques, and 25 (4.2%) had IPH in carotid arteries. HbA1c was associated with the presence of IPH (OR, 1.94; 95% CI, 1.38-2.73) in the univariate analysis, and the association remained significant after adjustment for age, sex, traditional vascular factors, high-sensitivity C-reactive protein, and other potential confounders (OR, 1.70; 95% CI, 1.14-2.52).Conclusions This study showed that high HbA1c was associated with carotid plaque IPH detected by HR-MRI, which suggests that individuals with high HbA1c may have a higher risk of developing vulnerable carotid plaques.

Objectives To evaluate the feasibility and reproducibility of 2D and 3D black-blood sequences in measuring morphology of renal arterial wall. Methods The 2D and 3D imaging sequences used variable-refocusing-flip-angle and constant-low-refocusing-flip-angle turbo spin echo (TSE) readout respectively, with delicately selected black-blood scheme and respiratory motion trigger for free-breathing imaging. Fourteen healthy subjects and three patients with Takayasu arteritis underwent renal artery wall imaging with 3D double inversion recovery (DIR) TSE and 2D Variable Flip Angle-TSE (VFA-TSE) black-blood sequences at 3.0 T. Four healthy subjects were randomly selected for scan-rescan reproducibility experiments. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and morphology of arterial wall were measured and compared using paired-t-test or Wilcoxon signed-rank test between 2D and 3D sequences. The inter-observer, intra-observer and scan-rescan agreements of above measurements were determined using intraclass correlation coefficient (ICC). Results The 2D and 3D imaging sequences showed similar morphological measurements (lumen area, wall area, mean wall thickness and maximum wall thickness) of renal arterial wall (all P > 0.05) and excellent agreement (ICC: 0.853–0.954). Compared to 2D imaging, 3D imaging exhibited significantly lower SNRlumen (P Conclusions Both high-resolution free-breathing 2D VFA-TSE and 3D DIR TSE black-blood sequences are feasible and reproducible in high-resolution renal arterial wall imaging. The 2D imaging has high SNR, whereas 3D imaging has high imaging efficiency.

Understanding the derivation process from Fourier's number to Fourier transformation is an important part in the study of Fourier transformation. This paper uses the graphical representation method of mathematics subject knowledge, clarifies the connection between the knowledge points in the process of Fourier's transformation, chooses the appropriate kind of illustration, and represents the derivation process of the Fourier series by illustration, and achieves the effect of image specific and reduces the difficulty of understanding in learning.

This two-part study first proposes the Generalized DC (GDC) power flow formulation which makes critical enhancements to the DC model by addressing its model limitations, with abilities to approximate bus voltage magnitudes and model networks with high resistance to reactance (R/X) ratio. Then, the GDC is applied to the current RTO electricity market clearing algorithms to model bus voltage security constraints. Case studies have successfully validated the GDC model capabilities and the new market clearing algorithm with voltage security enhancement. In addition, the incorporation of voltage security constraints supports reactive power pricing that helps incentivize voltage support via the market mechanism.