Publications by authors named "Lirong Yan"

74 Publications

Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla.

Neuroimage 2021 Nov 12;245:118724. Epub 2021 Nov 12.

Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA. Electronic address:

Laminar fMRI based on BOLD and CBV contrast at ultrahigh magnetic fields has been applied for studying the dynamics of mesoscopic brain networks. However, the quantitative interpretations of BOLD/CBV fMRI results are confounded by different baseline physiology across cortical layers. Here we introduce a novel 3D zoomed pseudo-continuous arterial spin labeling (pCASL) technique at 7T that offers the capability for quantitative measurements of laminar cerebral blood flow (CBF) both at rest and during task activation with high spatial specificity and sensitivity. We found arterial transit time in superficial layers is ∼100 ms shorter than in middle/deep layers revealing the time course of labeled blood flowing from pial arteries to downstream microvasculature. Resting state CBF peaked in the middle layers which is highly consistent with microvascular density measured from human cortex specimens. Finger tapping induced a robust two-peak laminar profile of CBF increases in the superficial (somatosensory and premotor input) and deep (spinal output) layers of M1, while finger brushing task induced a weaker CBF increase in superficial layers (somatosensory input). This observation is highly consistent with reported laminar profiles of CBV activation on M1. We further demonstrated that visuospatial attention induced a predominant CBF increase in deep layers and a smaller CBF increase on top of the lower baseline CBF in superficial layers of V1 (feedback cortical input), while stimulus driven activity peaked in the middle layers (feedforward thalamic input). With the capability for quantitative CBF measurements both at baseline and during task activation, high-resolution ASL perfusion fMRI at 7T provides an important tool for in vivo assessment of neurovascular function and metabolic activities of neural circuits across cortical layers.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118724DOI Listing
November 2021

Identification of potential novel biomarkers for abdominal aortic aneurysm based on comprehensive analysis of circRNA-miRNA-mRNA networks.

Exp Ther Med 2021 Dec 21;22(6):1468. Epub 2021 Oct 21.

Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.

Abdominal aortic aneurysm (AAA) is a life-threatening disorder and, therefore, investigation into its underlying mechanisms in light of the competing endogenous RNAs (ceRNAs) hypothesis has gradually increased. However, there is still lacking systematic analysis on AAA-associated circular RNA (circRNA)-microRNA (miRNA/miR)-messenger RNA (mRNA) interaction networks based on bioinformatics methods. The present study attempted to identify novel molecular biomarkers for AAA by profiling circRNA-miRNA-mRNA networks using three public microarray datasets (GSE7084, GSE57691 and GSE144431). A total of 135 differentially expressed genes (DEGs) and 142 differentially expressed circRNAs were detected using the limma R package with the statistical threshold of P<0.05 and |logfold change (FC)| >1.5. In addition, 12 circRNA-miRNA-mRNA axes were identified to construct upregulated and downregulated ceRNA networks using Cytoscape. Based on molecular complex detection algorithm, (hsa_circ_0057691/0092108/0006845/0082182)- miR-330-5p-calponin 1 (CNN1) and (hsa_circ_0061482/0011450/0008351/0004121)-miR-326-CD8a molecule (CD8A) were recognized as the center axes in ceRNA networks. Reverse transcription-quantitative PCR results verified the significant downregulation of CNN1 and upregulation of CD8A in human AAA tissues (P<0.05). In addition, four upregulated circRNA/mRNA axes, and five downregulated circRNA/mRNA axes were revealed to have possible biological functions in the pathogenesis of AAA using the Cytoscape software. Receiver operating characteristic analysis demonstrated the accuracy of these nine DEGs involved in these axes for AAA diagnosis with area under the curves >0.80. The present study revealed novel circRNA-miRNA-mRNA networks associated with AAA, especially for CNN1 and CD8A axes with the potential function of 'focal adhesion' and 'immune response', respectively. Overall, the present findings may provide evidence to explore the implicated ceRNAs in the molecular mechanisms and as novel biomarkers for AAA.
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http://dx.doi.org/10.3892/etm.2021.10903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8561771PMC
December 2021

Study of Auditory Brain Cognition Laws-Based Recognition Method of Automobile Sound Quality.

Front Hum Neurosci 2021 8;15:663049. Epub 2021 Oct 8.

Hubei Key Laboratory of Advanced Technology for Automotive Components, Wuhan University of Technology, Wuhan, China.

The research shows that subjective feelings of people, such as emotions and fatigue, can be objectively reflected by electroencephalography (EEG) physiological signals Thus, an evaluation method based on EEG, which is used to explore auditory brain cognition laws, is introduced in this study. The brain cognition laws are summarized by analyzing the EEG power topographic map under the stimulation of three kinds of automobile sound, namely, quality of comfort, powerfulness, and acceleration. Then, the EEG features of the subjects are classified through a machine learning algorithm, by which the recognition of diversified automobile sound is realized. In addition, the Kalman smoothing and minimal redundancy maximal relevance (mRMR) algorithm is used to improve the recognition accuracy. The results show that there are differences in the neural characteristics of diversified automobile sound quality, with a positive correlation between EEG energy and sound intensity. Furthermore, by using the Kalman smoothing and mRMR algorithm, recognition accuracy is improved, and the amount of calculation is reduced. The novel idea and method to explore the cognitive laws of automobile sound quality from the field of brain-computer interface technology are provided in this study.
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http://dx.doi.org/10.3389/fnhum.2021.663049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8533456PMC
October 2021

Optimization of pseudo-continuous arterial spin labeling at 7T with parallel transmission B1 shimming.

Magn Reson Med 2022 Jan 24;87(1):249-262. Epub 2021 Aug 24.

Laboratory of FMRI Technology, USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

Purpose: To optimize pseudo-continuous arterial spin labeling (pCASL) for 7 T, and to further improve the labeling efficiency with parallel RF transmission transmit B ( ) shimming.

Methods: pCASL parameters were optimized based on field distributions at 7 T with simulation. To increase labeling efficiency, the amplitude at inflowing arteries was increased with parallel RF transmission shimming. The "indv-shim" with shimming weights calculated for each individual subject, and the "univ-shim" with universal weights calculated on a group of 12 subjects, were compared with circular polarized (CP) shim. The optimized pCASL sequences with three shimming modes (indv-shim, univ-shim, and CP-shim) were evaluated in 6 subjects who underwent two repeated scans 24 hours apart, along with a pulsed ASL sequence. Quantitative metrics including mean amplitude, perfusion, and intraclass correlation coefficient were calculated. The optimized 7T pCASL was compared with standard 3T pCASL on 5 subjects, using spatial SNR and temporal SNR.

Results: The optimal pCASL parameter set (RF duration/gap = 300/250 us, ) achieved robust perfusion measurement in the presence of inhomogeneities. Both indv-shim and univ-shim significantly increased amplitude compared with CP-shim in simulation and in vivo experiment (P < .01). Compared with CP-shim, perfusion signal was increased by 9.5% with indv-shim (P < .05) and by 5.3% with univ-shim (P = .35). All three pCASL sequences achieved fair to good repeatability (intraclass correlation coefficient ≥ 0.5). Compared with 3T pCASL, the optimized 7T pCASL achieved 78.3% higher spatial SNR and 200% higher temporal SNR.

Conclusion: The optimized pCASL achieved robust perfusion imaging at 7 T, while both indv-shim and univ-shim further increased labeling efficiency.
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http://dx.doi.org/10.1002/mrm.28988DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8616784PMC
January 2022

12 weeks of strength training improves fluid cognition in older adults: A nonrandomized pilot trial.

PLoS One 2021 22;16(7):e0255018. Epub 2021 Jul 22.

Division of Biokinesiology and Physical Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States of America.

Objectives: Resistance training (RT) is a promising strategy to slow or prevent fluid cognitive decline during aging. However, the effects of strength-specific RT programs have received little attention. The purpose of this single-group proof of concept clinical trial was to determine whether a 12-week strength training (ST) program could improve fluid cognition in healthy older adults 60 to 80 years of age, and to explore concomitant physiological and psychological changes.

Methods: Twenty participants (69.1 ± 5.8 years, 14 women) completed this study with no drop-outs or severe adverse events. Baseline assessments were completed before an initial 12-week control period, then participants were re-tested at pre-intervention and after the 12-week ST intervention. The NIH Toolbox Cognition Battery and standard physical and psychological measures were administered at all three time points. During the 36 sessions of periodized ST (3 sessions per week), participants were supervised by an exercise specialist and challenged via autoregulatory load progression.

Results: Test-retest reliability over the control period was good for fluid cognition and excellent for crystallized cognition. Fluid composite scores significantly increased from pre- to post-intervention (8.2 ± 6.1%, p < 0.01, d = 1.27), while crystallized composite scores did not (-0.5 ± 2.8%, p = 0.46, d = -0.34). Performance on individual fluid instruments, including executive function, attention, working memory, and processing speed, also significantly improved. Surprisingly, changes in fluid composite scores had small negative correlations with changes in muscular strength and sleep quality, but a small positive correlation with changes in muscular power.

Conclusions: Thus, improvements in fluid cognition can be safely achieved in older adults using a 12-week high-intensity ST program, but further controlled studies are needed to confirm these findings. Furthermore, the relationship with other widespread physiological and psychological benefits remains unclear.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0255018PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297768PMC
November 2021

Massively parallel functional photoacoustic computed tomography of the human brain.

Nat Biomed Eng 2021 May 31. Epub 2021 May 31.

Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, USA.

Blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging of the human brain requires bulky equipment for the generation of magnetic fields. Photoacoustic computed tomography obviates the need for magnetic fields by using light and sound to measure deoxyhaemoglobin and oxyhaemoglobin concentrations to then quantify oxygen saturation and blood volumes. Yet, the available imaging speeds, fields of view (FOV), sensitivities and penetration depths have been insufficient for functional imaging of the human brain. Here, we show that massively parallel ultrasonic transducers arranged hemispherically around the human head can produce tomographic images of the brain with a 10-cm-diameter FOV and spatial and temporal resolutions of 350 µm and 2 s, respectively. In patients who had a hemicraniectomy, a comparison of functional photoacoustic computed tomography and 7 T BOLD functional magnetic resonance imaging showed a strong spatial correspondence in the same FOV and a high temporal correlation between BOLD signals and photoacoustic signals, with the latter enabling faster detection of functional activation. Our findings establish the use of photoacoustic computed tomography for human brain imaging.
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http://dx.doi.org/10.1038/s41551-021-00735-8DOI Listing
May 2021

Altered regional cerebral blood flow in obstructive sleep apnea is associated with sleep fragmentation and oxygen desaturation.

J Cereb Blood Flow Metab 2021 10 28;41(10):2712-2724. Epub 2021 Apr 28.

Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA.

Altered cerebral perfusion has been reported in obstructive sleep apnea (OSA). Using dynamic susceptibility contrast MRI, we compared cerebral perfusion between male OSA patients and male healthy reference subjects and assessed correlations of perfusion abnormalities of OSA patients with sleep parameters and neuropsychological deficits at 3 T MRI, polysomnography and neuropsychological tests in 68 patients with OSA and 21 reference subjects. We found lower global and regional cerebral blood flow and cerebral blood volume, localized mainly in bilateral parietal and prefrontal cortices, as well as multiple focal cortical and deep structures related to the default mode network and attention network. In the correlation analysis between regional hypoperfusion and parameters of polysomnography, different patterns of regional hypoperfusion were distinctively associated with parameters of intermittent hypoxia and sleep fragmentation, which involved mainly parietal and orbitofrontal cortices, respectively. There was no association between brain perfusion and cognition in OSA patients in areas where significant association was observed in reference subjects, largely overlapping with nodes of the default mode network and attention network. Our results suggest that impaired cerebral perfusion in important areas of functional networks could be an important pathomechanism of neurocognitive deficits in OSA.
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http://dx.doi.org/10.1177/0271678X211012109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504950PMC
October 2021

An Evaluation of Executive Control Function and Its Relationship with Driving Performance.

Sensors (Basel) 2021 Mar 4;21(5). Epub 2021 Mar 4.

Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory, Foshan 528200, China.

The driver's attentional state is a significant human factor in traffic safety. The executive control process is a crucial sub-function of attention. To explore the relationship between the driver's driving performance and executive control function, a total of 35 healthy subjects were invited to take part in a simulated driving experiment and a task-cuing experiment. The subjects were divided into three groups according to their driving performance (aberrant driving behaviors, including lapses and errors) by the clustering method. Then the performance efficiency and electroencephalogram (EEG) data acquired in the task-cuing experiment were compared among the three groups. The effect of group, task transition types and cue-stimulus intervals (CSIs) were statistically analyzed by using the repeated measures analysis of variance (ANOVA) and the post hoc simple effect analysis. The subjects with lower driving error rates had better executive control efficiency as indicated by the reaction time (RT) and error rate in the task-cuing experiment, which was related with their better capability to allocate the available attentional resources, to express the external stimuli and to process the information in the nervous system, especially the fronto-parietal network. The activation degree of the frontal area fluctuated, and of the parietal area gradually increased along with the increase of CSI, which implied the role of the frontal area in task setting reconstruction and working memory maintaining, and of the parietal area in stimulus-Response (S-R) mapping expression. This research presented evidence of the close relationship between executive control functions and driving performance.
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http://dx.doi.org/10.3390/s21051763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961377PMC
March 2021

Relationship of paced left bundle branch pacing morphology with anatomic location and physiological outcomes.

Heart Rhythm 2021 Jun 27;18(6):946-953. Epub 2021 Mar 27.

State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

Background: Left bundle branch pacing (LBBP) is an emerging physiological pacing modality. However, little is known about pacing at different locations on the left bundle branch (LBB).

Objective: The purpose of this study was to explore pacing and physiological characteristics associated with different LBBP locations.

Methods: The study included 68 consecutive patients with normal unpaced QRS duration and successful LBBP implantation. Patients were divided into 3 groups according to the paced QRS complex as left bundle branch trunk pacing (LBTP), left posterior fascicular pacing (LPFP), or left anterior fascicular pacing (LAFP). Electrocardiographic (ECG) characteristics, pacing parameters, and fluoroscopic localization were collected and analyzed.

Results: There were 17 (25.0%), 35 (51.5%), and 16 (23.5%) patients in the LBTP, LPFP, and LAFP groups, respectively. All subgroups had relatively narrow paced QRS complex (128.6 ± 9.1 ms vs 133.7 ± 11.2 ms vs 134.8 ± 9.6 ms; P = .170), fast left ventricular activation (70.4 ± 9.0 ms vs 70.6 ± 10.2 ms vs 71.0 ± 9.0 ms; P = .986), as well as low and stable pacing thresholds. Delayed right ventricular activation and interventricular dyssynchrony were similar between groups. Fluoroscopic imaging indicated that the lead tip was located most commonly in the basal-middle region of the septum (67.7%), and this was independent of paced QRS morphology group (88.2% vs 57.1% vs 68.8%; P = .106).

Conclusion: Pacing at different sites of the LBB resulted in similar intraventricular and interventricular electrical synchrony in patients with an intact conduction system. Fluoroscopic imaging alone could not predict specific LBBP paced ECG morphology.
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http://dx.doi.org/10.1016/j.hrthm.2021.03.034DOI Listing
June 2021

In-vivo imaging of targeting and modulation of depression-relevant circuitry by transcranial direct current stimulation: a randomized clinical trial.

Transl Psychiatry 2021 02 24;11(1):138. Epub 2021 Feb 24.

University of California, Los Angeles, CA, USA.

Recent clinical trials of transcranial direct current stimulation (tDCS) in depression have shown contrasting results. Consequently, we used in-vivo neuroimaging to confirm targeting and modulation of depression-relevant neural circuitry by tDCS. Depressed participants (N = 66, Baseline Hamilton Depression Rating Scale (HDRS) 17-item scores ≥14 and <24) were randomized into Active/Sham and High-definition (HD)/Conventional (Conv) tDCS groups using a double-blind, parallel design, and received tDCS individually targeted at the left dorsolateral prefrontal cortex (DLPFC). In accordance with Ampere's Law, tDCS currents were hypothesized to induce magnetic fields at the stimulation-target, measured in real-time using dual-echo echo-planar-imaging (DE-EPI) MRI. Additionally, the tDCS treatment trial (consisting of 12 daily 20-min sessions) was hypothesized to induce cerebral blood flow (CBF) changes post-treatment at the DLPFC target and in the reciprocally connected anterior cingulate cortex (ACC), measured using pseudo-continuous arterial spin labeling (pCASL) MRI. Significant tDCS current-induced magnetic fields were observed at the left DLPFC target for both active stimulation montages (Brodmann's area (BA) 46: p = 0.048, Cohen's d = 0.73; p = 0.018, d = 0.86; BA 9: p = 0.011, d = 0.92; p = 0.022, d = 0.83). Significant longitudinal CBF increases were observed (a) at the left DLPFC stimulation-target for both active montages (p = 3.5E-3, d = 0.98; p = 2.8E-3, d = 1.08), and (b) at ACC for the HD-montage only (p = 2.4E-3, d = 1.06; p = 0.075, d = 0.64). These results confirm that tDCS-treatment (a) engages the stimulation-target, and (b) modulates depression-relevant neural circuitry in depressed participants, with stronger network-modulations induced by the HD-montage. Although not primary outcomes, active HD-tDCS showed significant improvements of anhedonia relative to sham, though HDRS scores did not differ significantly between montages post-treatment.
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http://dx.doi.org/10.1038/s41398-021-01264-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904813PMC
February 2021

Evaluation of Cerebral Blood Flow Measured by 3D PCASL as Biomarker of Vascular Cognitive Impairment and Dementia (VCID) in a Cohort of Elderly Latinx Subjects at Risk of Small Vessel Disease.

Front Neurosci 2021 27;15:627627. Epub 2021 Jan 27.

Laboratory of FMRI Technology, USC Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.

Cerebral small vessel disease (cSVD) affects arterioles, capillaries, and venules and can lead to cognitive impairments and clinical symptomatology of vascular cognitive impairment and dementia (VCID). VCID symptoms are similar to Alzheimer's disease (AD) but the neurophysiologic alterations are less well studied, resulting in no established biomarkers. The purpose of this study was to evaluate cerebral blood flow (CBF) measured by 3D pseudo-continuous arterial spin labeling (pCASL) as a potential biomarker of VCID in a cohort of elderly Latinx subjects at risk of cSVD. Forty-five elderly Latinx subjects (12 males, 69 ± 7 years) underwent repeated MRI scans ∼6 weeks apart. CBF was measured using 3D pCASL in the whole brain, white matter and 4 main vascular territories (leptomeningeal anterior, middle, and posterior cerebral artery (leptoACA, leptoMCA, leptoPCA), as well as MCA perforator). The test-retest repeatability of CBF was assessed by intra-class correlation coefficient (ICC) and within-subject coefficient of variation (wsCV). Absolute and relative CBF was correlated with gross cognitive measures and domain specific assessment of executive and memory function, vascular risks, and Fazekas scores and volumes of white matter hyperintensity (WMH). Neurocognitive evaluations were performed using Montreal Cognitive Assessment (MoCA) and neuropsychological test battery in the Uniform Data Set v3 (UDS3). Good to excellent test-retest repeatability was achieved (ICC = 0.77-0.85, wsCV 3-9%) for CBF measurements in the whole brain, white matter, and 4 vascular territories. Relative CBF normalized by global mean CBF in the leptoMCA territory was positively correlated with the executive function composite score, while relative CBF in the leptoMCA and MCA perforator territory was positively correlated with MoCA scores, controlling for age, gender, years of education, and testing language. Relative CBF in WM was negatively correlated with WMH volume and MoCA scores, while relative leptoMCA CBF was positively correlated with WMH volume. Reliable 3D pCASL CBF measurements were achieved in the cohort of elderly Latinx subjects. Relative CBF in the leptomeningeal and perforator MCA territories were the most likely candidate biomarker of VCID. These findings need to be replicated in larger cohorts with greater variability of stages of cSVD.
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http://dx.doi.org/10.3389/fnins.2021.627627DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7873482PMC
January 2021

Assessment of carotid stiffness by measuring carotid pulse wave velocity using a single-slice oblique-sagittal phase-contrast MRI.

Magn Reson Med 2021 07 5;86(1):442-455. Epub 2021 Feb 5.

USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

Purpose: Increased arterial stiffness has been shown to be one of the earliest markers of cerebrovascular dysfunction. As a surrogate marker of arterial stiffness, pulse wave velocity (PWV) quantifications are generally carried out on central and peripheral arteries. The purpose of this study was to develop and evaluate an MRI approach to assess carotid stiffness by measuring carotid PWV (cPWV) using a fast oblique-sagittal phase-contrast MRI sequence.

Methods: In 29 volunteers, a single-slice oblique-sagittal phase-contrast MRI sequence with retrospective cardiac gating was used to quantify blood velocity waveforms along a vessel segment covering the common carotid artery (CCA) and the internal carotid artery (ICA). The CCA-ICA segment length was measured from a region of interest selected on the magnitude image. Phase-contrast MRI-measured velocities were also used to quantify the ICA pulsatility index along with cPWV quantification.

Results: The mean value of cPWV calculated using the middle upslope area algorithm was 2.86 ± 0.71 and 3.97 ± 1.14 m/s in young and elderly subjects, respectively. Oblique-sagittal phase-contrast MRI-derived cPWV measurements showed excellent intrascan and interscan repeatability. cPWV and ICA pulsatility index were significantly greater in older subjects compared to those in the young subjects (P < .01 and P = .01, respectively). Also, increased cPWV values were associated with elevated systolic blood pressure (β = 0.05, P = .03).

Conclusion: This study demonstrated that oblique-sagittal phase-contrast MRI is a feasible technique for the quantification of both cPWV and ICA pulsatility index and showed their potential utility in evaluating cerebroarterial aging and age-related neurovascular disorders.
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http://dx.doi.org/10.1002/mrm.28677DOI Listing
July 2021

Optimization of adiabatic pulses for pulsed arterial spin labeling at 7 tesla: Comparison with pseudo-continuous arterial spin labeling.

Magn Reson Med 2021 06 11;85(6):3227-3240. Epub 2021 Jan 11.

Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

Purpose: To optimize and evaluate adiabatic pulses for pulsed arterial spin labeling at ultrahigh field 7 tesla.

Methods: Four common adiabatic inversion pulses, including hyperbolic secant, wideband uniform rate smooth truncation, frequency offset corrected inversion, and time-resampled frequency offset corrected inversion pulses, were optimized based on a custom-defined loss function that included labeling efficiency and inversion band uniformity. The optimized pulses were implemented in flow-sensitive alternating inversion recovery sequences and tested on phantom and 11 healthy volunteers with 2 constraints: 1) specific absorption rate normalized; and 2) equal peak RF amplitude, respectively. A pseudo-continuous arterial spin labeling sequence was implemented for comparison. Quantitative metrics such as perfusion and relative labeling efficiency versus residual tissue signal were calculated.

Results: Among the 4 pulses, the wideband uniform rate smooth truncation pulse yielded the lowest loss in simulation and achieved a good balance between labeling efficiency and residual tissue signal from both phantom and in vivo experiments. Wideband uniform rate smooth truncation-pulsed arterial spin labeling showed significantly higher relative labeling efficiency compared to the other sequences (P < .01), whereas the perfusion signal was increased by 40% when the highest amplitude was used. The 4 pulsed arterial spin labeling sequences yielded comparable perfusion signals compared to pseudo-continuous arterial spin labeling but with less than half the specific absorption rate.

Conclusion: Optimized wideband uniform rate smooth truncation pulse with the highest amplitude allowed was recommended for 7 tesla pulsed arterial spin labeling.
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http://dx.doi.org/10.1002/mrm.28661DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8351166PMC
June 2021

Feasibility and efficacy of left bundle branch area pacing in patients indicated for cardiac resynchronization therapy.

Europace 2020 12;22(Suppl_2):ii54-ii60

State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Xicheng District, Beijing 100037, China.

Aims: The present study was to evaluate the feasibility and clinical outcomes of left bundle branch area pacing (LBBAP) in cardiac resynchronization therapy (CRT)-indicated patients.

Methods And Results: LBBAP was performed via transventricular septal approach in 25 patients as a rescue strategy in 5 patients with failed left ventricular (LV) lead placement and as a primary strategy in the remaining 20 patients. Pacing parameters, procedural characteristics, electrocardiographic, and echocardiographic data were assessed at implantation and follow-up. Of 25 enrolled CRT-indicated patients, 14 had left bundle branch block (LBBB, 56.0%), 3 right bundle branch block (RBBB, 12.0%), 4 intraventricular conduction delay (IVCD, 16.0%), and 4 ventricular pacing dependence (16.0%). The QRS duration (QRSd) was significantly shortened by LBBAP (intrinsic 163.6 ± 29.4 ms vs. LBBAP 123.0 ± 10.8 ms, P < 0.001). During the mean follow-up of 9.1 months, New York Heart Association functional class was improved to 1.4 ± 0.6 from baseline 2.6 ± 0.6 (P < 0.001), left ventricular ejection fraction (LVEF) increased to 46.9 ± 10.2% from baseline 35.2 ± 7.0% (P < 0.001), and LV end-diastolic dimensions (LVEDD) decreased to 56.8 ± 9.7 mm from baseline 64.1 ± 9.9 mm (P < 0.001). There was a significant improvement (34.1 ± 7.4% vs. 50.0 ± 12.2%, P < 0.001) in LVEF in patients with LBBB.

Conclusion: The present study demonstrates the clinical feasibility of LBBAP in CRT-indicated patients. Left bundle branch area pacing generated narrow QRSd and led to reversal remodelling of LV with improvement in cardiac function. LBBAP may be an alternative to CRT in patients with failure of LV lead placement and a first-line option in selected patients such as those with LBBB and heart failure.
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http://dx.doi.org/10.1093/europace/euaa271DOI Listing
December 2020

Semiautomatic cerebrovascular territory mapping based on dynamic ASL MR angiography without vessel-encoded labeling.

Magn Reson Med 2021 05 21;85(5):2735-2746. Epub 2020 Dec 21.

USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.

Purpose: Characterizing vessel territories can provide crucial information for evaluation of cerebrovascular disorders. In this study, we present a novel postprocessing pipeline for vascular territorial imaging of cerebral arteries based on a noncontrast enhanced time-resolved 4D magnetic resonance angiography (MRA).

Methods: Eight healthy participants, 1 Moyamoya patient, and 1 arteriovenous malformations patient were recruited. Territorial segmentation and relative blood flow rate calculations of cerebral arteries including left and right middle cerebral arteries and left and right posterior cerebral arteries were carried out based on the 4D MRA-derived arterial arrival time maps of intracranial vessels.

Results: Among healthy young subjects, the average relative blood flow rate values corresponding to left and right middle cerebral arteries and left and right posterior cerebral arteries were 35.9 ± 5.9%, 32.9 ± 7.5%, 15.4 ± 3.8%, and 15.9 ± 2.5%, respectively. Excellent agreement was observed between relative blood flow rate values obtained from the proposed 4D MRA-based method and reference 2D phase contrast MRI. Abnormal cerebral circulations were visualized and quantified on both patients using the developed technique.

Conclusion: The vascular territorial imaging technique developed in this study allowed for the generation of territorial maps with user-defined level of details within a clinically feasible scan time, and as such may provide useful information to assess cerebral circulation balance in different pathologies.
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http://dx.doi.org/10.1002/mrm.28623DOI Listing
May 2021

Comparison Between Blood-Brain Barrier Water Exchange Rate and Permeability to Gadolinium-Based Contrast Agent in an Elderly Cohort.

Front Neurosci 2020 30;14:571480. Epub 2020 Nov 30.

Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.

Dynamic contrast-enhanced (DCE) MRI using intravenous injection of gadolinium-based contrast agents (GBCAs) is commonly used for imaging blood-brain barrier (BBB) permeability. Water is an alternative endogenous tracer with limited exchange rate across the BBB. A direct comparison between BBB water exchange rate and BBB permeability to GBCA is missing. The purpose of this study was to directly compare BBB permeability to GBCA (Ktrans and k = Ktrans/Vp) and water exchange rate (kw) in a cohort of elderly subjects at risk of cerebral small vessel disease (cSVD). Ktrans/k and kw were measured by DCE-MRI and diffusion prepared pseudo-continuous arterial spin labeling (DP-pCASL), respectively, at 3 Tesla in 16 elderly subjects (3 male, age = 67.9 ± 3.0 yrs) at risk of cSVD. The test-retest reproducibility of kw measurements was evaluated with repeated scans ~6 weeks apart. Mixed effects linear regression was performed in the whole brain, gray matter (GM), white matter (WM), and 6 subcortical brain regions to investigate associations between Ktrans/k and test-retest kw. In addition, kw and Ktrans/k were compared in normal appearing white matter (NAWM), white matter hyperintensity (WMH) lesions and penumbra. Significant correlation was found between kw and Ktrans only in WM (β = 6.7 × 10, = 0.036), caudate (β = 8.6 × 10, = 0.029), and middle cerebral artery (MCA) perforator territory (β = 6.9 × 10, = 0.009), but not in the whole brain, GM or rest 5 brain regions. Significant correlation was found between kw and k in MCA perforator territory (β = 1.5 × 10, = 0.049), medial-temporal lobe (β = 3.5 × 10, = 0.032), and hippocampus (β = 3.4 × 10, = 0.038), but not in the rest brain regions. Good reproducibility of kw measurements (ICC=0.75) was achieved. Ktrans was significantly lower inside WMH than WMH penumbra (16.2%, = 0.026), and k was significantly lower in NAWM than in the WMH penumbra (20.8%, < 0.001). kw provides a measure of water exchange rate across the BBB with good test-retest reproducibility. The BBB mechanism underlying kw and Ktrans/k is likely to be different, as manifested by correlations in only three brain regions for each pair of comparison between kw and Ktrans or k.
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http://dx.doi.org/10.3389/fnins.2020.571480DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733970PMC
November 2020

High-Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-Dimensional MR Angiography, and Black Blood MR Imaging.

Magn Reson Imaging Clin N Am 2021 Feb 2;29(1):53-65. Epub 2020 Nov 2.

Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA. Electronic address:

Ultrahigh field offers increased resolution and contrast for neurovascular imaging. Arterial spin labeling methods benefit from an increased intrinsic signal-to-noise ratio of MR imaging signal and a prolonged tracer half-life at ultrahigh field, allowing the visualization of layer-dependent microvascular perfusion. Arterial spin labeling-based time-resolved 4-dimensional MR angiography at 7T provides a detailed depiction of the vascular architecture and dynamic blood flow pattern with high spatial and temporal resolutions. High-resolution black blood MR imaging at 7T allows detailed characterization of small perforating arteries such as lenticulostriate arteries. All techniques benefit from advances in parallel radiofrequency transmission technologies at ultrahigh field.
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http://dx.doi.org/10.1016/j.mric.2020.09.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694883PMC
February 2021

Efficacy and safety of ticagrelor and clopidogrel in East Asian patients with coronary artery disease undergoing percutaneous coronary intervention.

Curr Med Res Opin 2020 11 1;36(11):1739-1745. Epub 2020 Oct 1.

Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

Aims: The efficacy and safety of ticagrelor and clopidogrel in East Asian patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) remains uncertain. The purpose of this study was to compare the efficacy and safety of ticagrelor and clopidogrel in East Asian patients with CAD treated with PCI.

Methods: A total of 12383 patients with CAD undergoing PCI who received dual antiplatelet therapy (DAPT) were consecutively enrolled in the ticagrelor group ( = 1321) and the clopidogrel group ( = 11062). Major adverse cardiovascular and cerebrovascular events (MACCEs) and thrombolysis in myocardial infarction (TIMI) bleeding events were compared according to ticagrelor or clopidogrel use were compared.

Results: After propensity matching ( = 1321 in each group), ticagrelor was associated with lower incidence of MACCEs compared with clopidogrel (3.9 vs. 5.9%, hazard ratio [HR] = 0.65, 95% confidence interval [CI] 0.45-0.92,  = .015). The incidence of TIMI bleeding events was higher in the ticagrelor group than in the clopidogrel group (4.5 vs. 2.9%, HR = 1.90, 95% CI 1.25-2.88,  = .024). The difference between ticagrelor and clopidogrel for net adverse clinical events was nonsignificant (4.3 vs. 4.9%, HR = 0.88, 95% CI 0.61-1.27,  = .458).

Conclusions: Ticagrelor was associated with a lower incidence of MACCEs and an increased risk of TIMI bleeding events in East Asian patients with CAD receiving PCI.
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http://dx.doi.org/10.1080/03007995.2020.1825364DOI Listing
November 2020

Efficacy and Safety of Ticagrelor and Clopidogrel in Patients with Stable Coronary Artery Disease Undergoing Percutaneous Coronary Intervention.

J Atheroscler Thromb 2021 Aug 8;28(8):873-882. Epub 2020 Sep 8.

Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College.

Aim: The efficacy and safety of ticagrelor and clopidogrel in patients with stable coronary artery disease (SCAD) undergoing percutaneous coronary intervention (PCI) remain uncertain. Thus, this study aimed to compare the efficacy and safety of ticagrelor and clopidogrel in patients with SCAD treated with PCI.

Methods: A total of 9,379 patients with SCAD undergoing PCI who received dual antiplatelet therapy (DAPT) were consecutively enrolled in two groups, namely, ticagrelor (n=1,081) and clopidogrel (n=8,298) groups. Major adverse cardiovascular and cerebrovascular events (MACCEs) and bleeding events according to ticagrelor or clopidogrel use were compared.

Results: After propensity matching (n=1,081 in each group), ticagrelor was associated with fewer MACCEs compared with clopidogrel (3.6% vs. 5.7%, hazard ratio [HR]=0.62, 95% confidence interval [CI] 0.41-0.93, p=0.019), and the difference between ticagrelor and clopidogrel for bleeding events was nonsignificant (4.0% vs. 3.2%, HR=1.24, 95% CI 0.79-1.93, p=0.356). On the other hand, the difference between ticagrelor and clopidogrel for net adverse clinical events was significant (4.1% vs. 6.0%, HR=0.67, 95% CI 0.46-0.98, p=0.039). In a multivariate analysis, the use of ticagrelor, number of stents, previous history of diabetes, previous history of smoking, and ACC/AHA type B2 or C lesions were considered independent predictors of MACCEs, while radial artery access, previous history of stroke, and weight <60kg were independent predictors of bleeding events. Conclusions Ticagrelor was associated with a lower incidence of MACCEs without an increased risk of bleeding events in patients with SCAD receiving PCI.
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http://dx.doi.org/10.5551/jat.57265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8326171PMC
August 2021

Bilateral Bundle Branch Area Pacing to Achieve Physiological Conduction System Activation.

Circ Arrhythm Electrophysiol 2020 08 23;13(8):e008267. Epub 2020 Jul 23.

State Key Laboratory of Cardiovascular Disease, Arrhythmia Center (J.L., K.C., Y.D., Q.S., Y.L., Y.Z., R.C., Y. Jin, L.Y., S.Z.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.

Background: Left bundle branch pacing (LBBP) is a technique for conduction system pacing, but it often results in right bundle branch block morphology on the ECG. This study was designed to assess simultaneous pacing of the left and right bundle branch areas to achieve more synchronous ventricular activation.

Methods: In symptomatic bradycardia patients, the distal electrode of a bipolar pacing lead was placed at the left bundle branch area via a transventricular-septal approach. This was used to pace the left bundle branch area, while the ring electrode was used to pace the right bundle branch area. Bilateral bundle branch area pacing (BBBP) was achieved by stimulating the cathode and anode in various pacing configurations. QRS duration, delayed right ventricular activation time, left ventricular activation time, and interventricular conduction delay were measured. Pacing stability and short-term safety were assessed at 3-month follow-up.

Results: BBBP was successfully performed in 22 of 36 patients. Compared with LBBP, BBBP resulted in greater shortening of QRS duration (109.3±7.1 versus 118.4±5.7 ms, <0.001). LBBP resulted in a paced right bundle branch block configuration, with a delayed right ventricular activation time of 115.0±7.5 ms and interventricular conduction delay of 34.0±8.8 ms. BBBP fully resolved the right bundle branch block morphology in 18 patients. In the remaining 4 patients, BBBP partially corrected the right bundle branch block with delayed right ventricular activation time decreasing from 120.5±4.7 ms during LBBP to 106.1±4.2 ms during BBBP (=0.005).

Conclusions: LBBP results in a relatively narrow QRS complex but with an interventricular activation delay. BBBP can diminish the delayed right ventricular activation, producing more physiological ventricular activation. Graphic Abstract: A graphic abstract is available for this article.
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http://dx.doi.org/10.1161/CIRCEP.119.008267DOI Listing
August 2020

Improved depiction of subthalamic nucleus and globus pallidus internus with optimized high-resolution quantitative susceptibility mapping at 7 T.

NMR Biomed 2020 11 20;33(11):e4382. Epub 2020 Jul 20.

Stevens Neuroimaging and Informatics Institute, Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.

The subthalamic nucleus (STN) and globus pallidus internus (GPi) are commonly used targets in deep-brain stimulation (DBS) surgery for the treatment of movement disorders. The success of DBS critically depends on the spatial precision of stimulation. By taking advantage of good contrast between iron-rich deep-brain nuclei and surrounding tissues, quantitative susceptibility mapping (QSM) has shown promise in differentiating the STN and GPi from the adjacent substantia nigra and globus pallidus externus, respectively. Nonlinear morphology-enabled dipole inversion (NMEDI) is a widely used QSM algorithm, but the image quality of reconstructed susceptibility maps relies on the regularization parameter selection. To date, few studies have systematically optimized the regularization parameter at the ultra-high field of 7 T. In this study, we optimized the regularization parameter in NMEDI to improve the depiction of STN and GPi at different spatial resolutions at both 3 T and 7 T. The optimized QSM images were further compared with other susceptibility-based images, including T2*-weighted (T2*w), R2*, susceptibility-weighted, and phase images. QSM showed better depiction of deep-brain nuclei with clearer boundaries compared with the other methods, and 7 T QSM at 0.35 × 0.35 × 1.0 mm demonstrated superior performance to the others. Our findings suggest that optimized high-resolution QSM at 7 T allows for improved delineation of deep-brain nuclei with clear and sharp borders between nuclei, which may become a promising tool for DBS nucleus preoperative localization.
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http://dx.doi.org/10.1002/nbm.4382DOI Listing
November 2020

Reperfusion Into Severely Damaged Brain Tissue Is Associated With Occurrence of Parenchymal Hemorrhage for Acute Ischemic Stroke.

Front Neurol 2020 26;11:586. Epub 2020 Jun 26.

Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, USC, Los Angeles, CA, United States.

This study aims to quantify the reperfusion status within severely damaged brain tissue and to evaluate its relationship with high grade of hemorrhagic transformation (HT). Pseudo-continuous ASL was performed along with DWI in 102 patients within 24 h post-treatments. The infarction core was identified using ADC values <550 × 10 mm/s. CBF within the infarction core and its contralateral counterpart were acquired. CBF at the 25th, median, and 75th percentiles of the contralateral counterpart were used as thresholds and the ASL reperfusion volume above the threshold was labeled as vol-25, -50, and -75, respectively. Recanalization was defined according to Thrombolysis in Myocardial Infarction (TIMI) criteria. Quantified reperfusion within the infarction core differed significantly in patients with complete and incomplete recanalization. In the ROC analysis for the prediction of parenchymal hematoma (PH), ASL reperfusion vol-25 had the highest area under the curve (AUC) when compared with ASL vol-50 and ASL vol-75. ASL reperfusion vol-25 had significantly higher AUC compared with ADC threshold volume in the prediction of PH (0.783 vs. 0.685, = 0.0036) and PH-2 (0.844 vs. 0.754, = 0.0035). In stepwise multivariate logistic regression analysis, only ASL reperfusion vol-25 emerged as an independent predictor of PH (OR = 3.51, 95% CI: 1.65-7.45, < 0.001) and PH-2 (OR = 2.32, 95% CI: 1.13-4.76, = 0.022). Increased reperfusion volume within severely damaged brain tissue is associated with the occurrence of higher grade of HT.
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http://dx.doi.org/10.3389/fneur.2020.00586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7332705PMC
June 2020

Cerebroarterial pulsatility and resistivity indices are associated with cognitive impairment and white matter hyperintensity in elderly subjects: A phase-contrast MRI study.

J Cereb Blood Flow Metab 2021 03 5;41(3):670-683. Epub 2020 Jun 5.

USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.

Increased cerebroarterial pulsations are thought to be contributing factors in microvascular damage and cognitive impairment. In this study, we assessed the utility of two-dimensional (2D) phase-contrast MRI (PC-MRI) in quantifying cerebroarterial pulsations and evaluated the associations of pulsatile and non-pulsatile hemodynamic measures with cognitive performance and white matter hyperintensities (WMH). Neurocognitive assessments on 50 elderly subjects were performed using clinical dementia rating (CDR) and Montreal cognitive assessment (MoCA). An electrocardiogram-gated 2D PC-MRI sequence was used to calculate mean flow rate, pulsatility index (PI), and resistivity index (RI) of the internal carotid artery. For each subject, whole brain global cerebral blood flow (gCBF) and relative WMH volume were also quantified. Elevated RI was significantly associated with reduced cognitive performance quantified using MoCA (=0.04) and global CDR (=0.02). PI and RI were both significantly associated with relative WMH volume (=0.01, <0.01, respectively). However, non-pulsatile hemodynamic measures were not associated with cognitive impairment or relative WMH volume. This study showed that the cerebroarterial pulsatile measures obtained using PC-MRI have stronger association with the measures of cognitive impairment compared to global blood flow measurement and as such, might be useful as potential biomarkers of cerebrovascular dysfunction in preclinical populations.
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http://dx.doi.org/10.1177/0271678X20927101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922759PMC
March 2021

Concurrent Imaging of Markers of Current Flow and Neurophysiological Changes During tDCS.

Front Neurosci 2020 21;14:374. Epub 2020 Apr 21.

Laboratory of FMRI Technology, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States.

Despite being a popular neuromodulation technique, clinical translation of transcranial direct current stimulation (tDCS) is hampered by variable responses observed within treatment cohorts. Addressing this challenge has been difficult due to the lack of an effective means of mapping the neuromodulatory electromagnetic fields together with the brain's response. In this study, we present a novel imaging technique that provides the capability of concurrently mapping markers of tDCS currents, as well as the brain's response to tDCS. A dual-echo echo-planar imaging (DE-EPI) sequence is used, wherein the phase of the acquired MRI-signal encodes the tDCS current induced magnetic field, while the magnitude encodes the blood oxygenation level dependent (BOLD) contrast. The proposed technique was first validated in a custom designed phantom. Subsequent test-retest experiments in human participants showed that tDCS-induced magnetic fields can be detected reliably . The concurrently acquired BOLD data revealed large-scale networks characteristic of a brain in resting-state as well as a 'cathodal' and an 'anodal' resting-state component under each electrode. Moreover, 'cathodal's BOLD-signal was observed to significantly decrease with the applied current at the group level in all datasets. With its ability to image markers of electromagnetic cause as well as neurophysiological changes, the proposed technique may provide an effective means to visualize neural engagement in tDCS at the group level. Our technique also contributes to addressing confounding factors in applying BOLD fMRI concurrently with tDCS.
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http://dx.doi.org/10.3389/fnins.2020.00374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7186453PMC
April 2020

The value of serum uric acid levels to differentiate causes of transient loss of consciousness.

Epilepsy Behav 2019 10 30;99:106489. Epub 2019 Aug 30.

Department of Neurology, Beijing Jishuitan Hospital, 31 Xinjiekou East Street, Xicheng District, Beijing 100035, China. Electronic address:

Background: Generalized tonic-clonic seizures (GTCS), syncope, and psychogenic nonepileptic seizures (PNES) are common emergent neurological conditions that cause transient disturbances of consciousness; however, it is sometimes difficult to distinguish them.

Objective: This study aimed to explore the value of serum uric acid levels in differentiating among GTCS, syncope, and PNES by analyzing serum uric acid levels in patients with GTCS, syncope, and PNES.

Methods: A total of 391 patients were retrospectively analyzed. Venous blood was drawn from the patients within 20 min of their arrival to the emergency department; serum uric acid levels were measured using the uricase method.

Results: Serum uric acid levels and the percentage of patients with elevated uric acid (elevation percentage) were significantly higher in the group with GTCS (n = 179) than in the groups with syncope (n = 156) (p < 0.001) and PNES (n = 56) (p < 0.001). The result remained the same when the serum uric acid level of male or female patients in the group with GTCS were compared separately with that in the other two groups (all p < 0.001). In the group with GTCS, both the serum uric acid level (p < 0.001) and elevation percentage (p < 0.05) were significantly higher in males than in females. The receiver operating characteristics (ROC) analysis in male patients yielded a serum uric acid value of 428.50 μmol/L with a sensitivity of 0.78 and a specificity of 0.99 as the optimal cutoff value to distinguish GTCS from other events. In female patients, a cutoff value of 338.00 μmol/L had a sensitivity of 0.69 and a specificity of 0.91 to distinguish GTCS from other events. For the group with GTCS, the period of time between the onset of seizure and serum uric acid levels dropping to normal were analyzed in 40 patients. The duration was 44.56 ± 11.46 h for males (n = 23) and 40.37 ± 9.78 h for females (n = 17) with no significant difference (p = 0.325).

Conclusion: Serum uric acid levels provided certain clinical value for the differentiation of GTCS, syncope, and PNES; however, this requires verification in prospective studies with larger sample sizes.
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http://dx.doi.org/10.1016/j.yebeh.2019.106489DOI Listing
October 2019

Correlation Among Behavior, Personality, and Electroencephalography Revealed by a Simulated Driving Experiment.

Front Psychol 2019 3;10:1524. Epub 2019 Jul 3.

State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun, China.

Drivers play the most important role in the human-vehicle-environment system and driving behaviors are significantly influenced by the cognitive state of the driver and his/her personality. In this paper, we aimed to explore the correlation among driving behaviors, personality and electroencephalography (EEG) using a simulated driving experiment. A total of 36 healthy subjects participated in the study. The 64-channel EEG data and the driving data, including the real-time position of the vehicle, the rotation angle of the steering wheel and the speed were acquired simultaneously during driving. The Cattell 16 Personality Factor Questionnaire (16PF) was utilized to evaluate the personalities of subjects. Through hierarchical clustering of the 16PF personality traits, the subjects were divided into four groups, i.e., the Inapprehension group, Insensitivity group, Apprehension group and the Unreasoning group, named after their representative personality trait. Their driving performance and turning behaviors were compared and EEG preprocessing, source reconstruction and the comparisons among the four groups were performed using Statistical Parameter Mapping (SPM). The turning process of the subjects can be formulated into two steps, rotating the steering wheel toward the turning direction and entering the turn, and then rotating the steering wheel back and leaving the turn. The bilateral frontal gyrus was found to be activated when turning left and right, which might be associated with its function in attention, decision-making and executive control functions in visual-spatial and visual-motor processes. The Unreasoning group had the worst driving performance with highest rates of car collision and the most intensive driving action, which was related to a higher load of visual spatial attention and decision making, when the occipital and superior frontal areas played a very important role. Apprehension (O) and Tension (Q4) had a positive correlation, and Reasoning (B) had a negative correlation with dangerous driving behaviors. Our results demonstrated the close correlation among driving behaviors, personality and EEG and may be taken as a reference for the prediction and precaution of dangerous driving behaviors in people with specific personality traits.
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http://dx.doi.org/10.3389/fpsyg.2019.01524DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6626991PMC
July 2019

Behavior Evaluation Based on Electroencephalograph and Personality in a Simulated Driving Experiment.

Front Psychol 2019 4;10:1235. Epub 2019 Jun 4.

Hubei Key Laboratory of Advanced Technology for Automotive Components, Wuhan University of Technology, Wuhan, China.

Assessments and predictions of driving behavior are very important to improve traffic safety. We hypothesized that there were some patterns of driving behaviors, and these patterns had some correlation with cognitive states and personalities. To test this hypothesis, an evaluation of driving status, based on electroencephalography (EEG) and steering behavior in a simulated driving experiment, was designed and performed. Unity 3D was utilized to design the simulated driving scene. A photoelectric encoder fixed on the steering wheel and the corresponding data collection, transmission, and storage device was developed by Arduino, to acquire the rotation direction, angle, angular velocity, and angular acceleration of the steering wheel. Biopac MP 150 was utilized to collect the EEG data simultaneously during driving. A total of 23 subjects (mean age 23.6 ± 1.3 years, driving years: 2.4 ± 1.6 years, 21 males and two females) participated in this study. The Fuzzy C-means algorithm (FCMA) was utilized to extract patterns of driving behavior and the cognitive state within the window width of 20 s. The behaviors were divided into five kinds, i.e., negative, normal, alert, stress, and violent behavior, respectively, based on the standard deviation of steering wheel data. The cognitive states were divided into four kinds, i.e., negative, calm, alert, and tension, respectively, based on the EEG data. The correlation of these data, together with the personality traits evaluated using Cattell 16 Personality Factor Questionnaire (16PF) were analyzed using multiclass logistic regression. Results indicated the significance of the cognitive state and seven personality traits [apprehension (O), rule consciousness (G), reasoning (B), emotional stability (C), liveliness (F), vigilance (L), and perfectionism (Q3)] in predicting driving behaviors, and the prediction accuracy was 80.2%. The negative and alert cognitive states were highly correlated with dangerous driving, including negative and violent behaviors. Personality traits complicate the relationship with driving behaviors, which may vary across different types of subjects and traffic accidents.
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http://dx.doi.org/10.3389/fpsyg.2019.01235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558165PMC
June 2019

Recovery of complete left bundle branch block following heart failure improvement by left bundle branch pacing in a patient.

J Cardiovasc Electrophysiol 2019 09 3;30(9):1714-1717. Epub 2019 Jul 3.

State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

A 57-year-old male presented with symptomatic systolic heart failure and complete left bundle branch block (LBBB). Left bundle branch pacing corrected LBBB at a low capture threshold (0.5V @0.4ms) with right bundle branch conduction delay and paced QRS morphology changed to near-normal by adjusting AV delay with diminished RBBD. At 1-year follow-up, the patient had a significant improvement in heart failure and LBBB automatically resolved with a rate-dependent pattern. LBBP may be an alternative to conventional cardiac resynchronization therapy with the likelihood of recovery of LBBB. More research is needed to evaluate the potential use of this pacing strategy in patients with LBBB and heart failure.
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http://dx.doi.org/10.1111/jce.14034DOI Listing
September 2019

Driving Style Recognition Based on Electroencephalography Data From a Simulated Driving Experiment.

Front Psychol 2019 29;10:1254. Epub 2019 May 29.

Hubei Key Laboratory of Advanced Technology for Automotive Components, School of Automotive Engineering, Wuhan University of Technology, Wuhan, China.

Driving style is a very important indicator and a crucial measurement of a driver's performance and ability to drive in a safe and protective manner. A dangerous driving style would possibly result in dangerous behaviors. If the driving styles can be recognized by some appropriate classification methods, much attention could be paid to the drivers with dangerous driving styles. The driving style recognition module can be integrated into the advanced driving assistance system (ADAS), which integrates different modules to improve driving automation, safety and comfort, and then the driving safety could be enhanced by pre-warning the drivers or adjusting the vehicle's controlling parameters when the dangerous driving style is detected. In most previous studies, driver's questionnaire data and vehicle's objective driving data were utilized to recognize driving styles. And promising results were obtained. However, these methods were indirect or subjective in driving style evaluation. In this paper a method based on objective driving data and electroencephalography (EEG) data was presented to classify driving styles. A simulated driving system was constructed and the EEG data and the objective driving data were collected synchronously during the simulated driving. The driving style of each participant was classified by clustering the driving data via K-means. Then the EEG data was denoised and the amplitude and the Power Spectral Density (PSD) of four frequency bands were extracted as the EEG features by Fast Fourier transform and Welch. Finally, the EEG features, combined with the classification results of the driving data were used to train a Support Vector Machine (SVM) model and a leave-one-subject-out cross validation was utilized to evaluate the performance. The SVM classification accuracy was about 80.0%. Conservative drivers showed higher PSDs in the parietal and occipital areas in the alpha and beta bands, aggressive drivers showed higher PSD in the temporal area in the delta and theta bands. These results imply that different driving styles were related with different driving strategies and mental states and suggest the feasibility of driving style recognition from EEG patterns.
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http://dx.doi.org/10.3389/fpsyg.2019.01254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6549479PMC
May 2019

Characterization of lenticulostriate arteries with high resolution black-blood T1-weighted turbo spin echo with variable flip angles at 3 and 7 Tesla.

Neuroimage 2019 10 31;199:184-193. Epub 2019 May 31.

USC Stevens Neuroimaging and Informatics Institute, Department of Neurology, University of Southern California, Los Angeles, CA, USA. Electronic address:

Objectives: The lenticulostriate arteries (LSAs) with small diameters of a few hundred microns take origin directly from the high flow middle cerebral artery (MCA), making them especially susceptible to damage (e.g. by hypertension). This study aims to present high resolution (isotropic ∼0.5 mm), black blood MRI for the visualization and characterization of LSAs at both 3 T and 7 T.

Materials And Methods: T1-weighted 3D turbo spin-echo with variable flip angles (T1w TSE-VFA) sequences were optimized for the visualization of LSAs by performing extended phase graph (EPG) simulations. Twenty healthy volunteers (15 under 35 years old, 5 over 60 years old) were imaged with the T1w TSE-VFA sequences at both 3 T and 7 T. Contrast-to-noise ratio (CNR) was quantified, and LSAs were manually segmented using ITK-SNAP. Automated Reeb graph shape analysis was performed to extract features including vessel length and tortuosity. All quantitative metrics were compared between the two field strengths and two age groups using ANOVA.

Results: LSAs can be clearly delineated using optimized 3D T1w TSE-VFA at 3 T and 7 T, and a greater number of LSA branches can be detected compared to those by time-of-flight MR angiography (TOF MRA) at 7 T. The CNR of LSAs was comparable between 7 T and 3 T. T1w TSE-VFA showed significantly higher CNR than TOF MRA at the stem portion of the LSAs branching off the medial middle cerebral artery. The mean vessel length and tortuosity were greater on TOF MRA compared to TSE-VFA. The number of detected LSAs by both TSE-VFA and TOF MRA was significantly reduced in aged subjects, while the mean vessel length measured on 7 T TSE-VFA showed significant difference between the two age groups.

Conclusion: The high-resolution black-blood 3D T1w TSE-VFA sequence offers a new method for the visualization and quantification of LSAs at both 3 T and 7 T, which may be applied for a number of pathological conditions related to the damage of LSAs.
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http://dx.doi.org/10.1016/j.neuroimage.2019.05.065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688958PMC
October 2019
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