Zhangxuan Hu

All Publications

• Excessive iron accumulation in the striatum associated with addictive behaviors of medication-overuse headache: a prospective study. BMC medicine Pei, X., Bai, X., Zhang, X., Hu, Z., Wang, W., Zhang, X., Zhang, Y., Tang, H., Zhang, Y., Yu, X., Yuan, Z., Zhang, P., Chen, T., Zhao, Y., Jia, X., Yang, Q., Wang, Y., Sui, B. 2025; 23 (1): 300

  Abstract

  Abnormal iron deposition may be a biomarker for a disrupted central antinociceptive neuronal network, and the relationship between iron deposition and the pathophysiological mechanisms of chronic migraine (CM) with medication overuse (MOH) remains unclear. We investigated iron deposition in the deep gray matter (DGM) of the brain in CM patients with and without MOH using quantitative susceptibility mapping (QSM).Forty-eight healthy controls (HCs) and 69 CM patients (36 with MOH; 33 without MOH) were recruited. QSM data were acquired using a 3.0 T Magnetic resonance imaging (MRI). Regions of interest (ROI) in the DGM, including the bilateral caudate, putamen, globus pallidus (GP), hippocampus, nucleus accumbens, and amygdala, were segmented from the T1-weighted images (T1WI) of the whole brain of each individual patient using FreeSurfer. QSM images were registered to T1WI. QSM values within each ROI were extracted and compared between CM and HCs, as well as between CM with MOH and CM without MOH. Correlations between QSM values and clinical assessment scale scores were calculated. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of QSM values in these DGM for detecting CM and CM with MOH.Compared to HCs, CM patients exhibited increased iron deposition in the caudate (p = 0.013) and putamen (p < 0.001). In the CM without MOH group, headache duration correlated positively with iron deposition in the caudate (r = 0.502, p = 0.010) and putamen (r = 0.514, p = 0.009). CM with MOH patients showed greater iron deposition in the caudate (p < 0.001), putamen (p < 0.001), and GP (p = 0.049) than those without MOH, with medication use frequency correlating positively with iron deposition in the caudate (r = 0.427, p = 0.023) and putamen (r = 0.445, p = 0.018). ROC curve analysis indicated that the caudate (AUC = 0.736) and putamen (AUC = 0.729) exhibited high sensitivity and specificity in diagnosing CM with MOH.CM patients with MOH had excessive iron deposition in basal ganglia regions, including the caudate, putamen, and GP, which may be related to the medication overuse behavior. Iron deposition in the caudate and putamen may be a potential biomarker for CM with MOH. These findings provide insight into the common pathophysiological mechanisms underlying MOH and potential addiction.

  View details for DOI 10.1186/s12916-025-04125-8

  View details for PubMedID 40437522

  View details for PubMedCentralID PMC12121094

• Deep Convolutional Neural Network Enhanced Non-uniform Fast Fourier Transform for Undersampled MRI Reconstruction INTERNATIONAL JOURNAL OF COMPUTER VISION Li, Y., Qi, H., Hu, Z., Sun, H., Li, G., Zhang, Z., Liu, Y., Guo, H., Chen, H. 2025

  View details for DOI 10.1007/s11263-025-02378-7

  View details for Web of Science ID 001427780700001

• Reduced physiology-induced temporal instability achieved with variable-flip-angle fast low-angle excitation echo-planar technique with multishot echo planar time-resolved imaging MAGNETIC RESONANCE IN MEDICINE Hu, Z., Berman, A. L., Dong, Z., Grissom, W. A., Reese, T. G., Wald, L. L., Wang, F., Polimeni, J. R. 2024: 597-614

  Abstract

  Echo planar time-resolved imaging (EPTI) is a new imaging approach that addresses the limitations of EPI by providing high-resolution, distortion- and T2/ T 2 * $$ {\mathrm{T}}_2^{\ast } $$  blurring-free imaging for functional MRI (fMRI). However, as in all multishot sequences, intershot phase variations induced by physiological processes can introduce temporal instabilities to the reconstructed time-series data. This study aims to reduce these instabilities in multishot EPTI.In conventional multishot EPTI, the time intervals between the shots comprising each slice can introduce intershot phase variations. Here, the fast low-angle excitation echo-planar technique (FLEET), in which all shots of each slice are acquired consecutively with minimal time delays, was combined with a variable flip angle (VFA) technique to improve intershot consistency and maximize signal. A recursive Shinnar-Le Roux RF pulse design algorithm was used to generate pulses for different shots to produce consistent slice profiles and signal intensities across shots. Blipped controlled aliasing in parallel imaging simultaneous multislice was also combined with the proposed VFA-FLEET EPTI to improve temporal resolution and increase spatial coverage.The temporal stability of VFA-FLEET EPTI was compared with conventional EPTI at 7 T. The results demonstrated that VFA-FLEET can provide spatial-specific increase of temporal stability. We performed high-resolution task-fMRI experiments at 7 T using VFA-FLEET EPTI, and reliable BOLD responses to a visual stimulus were detected.The intershot phase variations induced by physiological processes in multishot EPTI can manifest as specific spatial patterns of physiological noise enhancement and lead to reduced temporal stability. The VFA-FLEET technique can substantially reduce these physiology-induced instabilities in multishot EPTI acquisitions. The proposed method provides sufficient stability and sensitivity for high-resolution fMRI studies.

  View details for DOI 10.1002/mrm.30301

  View details for Web of Science ID 001320190700001

  View details for PubMedID 39323238

  View details for PubMedCentralID PMC11661687

• Hyperperfusion of bilateral amygdala in patients with chronic migraine: an arterial spin-labeled magnetic resonance imaging study. The journal of headache and pain Bai, X., Wang, W., Zhang, X., Hu, Z., Zhang, X., Zhang, Y., Tang, H., Zhang, Y., Yu, X., Yuan, Z., Zhang, P., Li, Z., Pei, X., Wang, Y., Sui, B. 2023; 24 (1): 138

  Abstract

  Amygdala, an essential element of the limbic system, has served as an important structure in pain modulation. There is still a lack of clarity about altered cerebral perfusion of amygdala in migraine. This study aimed to investigate the perfusion variances of bilateral amygdala in episodic migraine (EM) and chronic migraine (CM) using multi-delay pseudo-continuous arterial spin-labeled magnetic resonance imaging (pCASL-MRI).Twenty-six patients with EM, 55 patients with CM (33 CM with medication overuse headache (MOH)), and 26 age- and sex-matched healthy controls (HCs) were included. All participants underwent 3D multi-delay pCASL MR imaging to obtain cerebral perfusion data, including arrival-time-corrected cerebral blood flow (CBF) and arterial cerebral blood volume (aCBV). The CBF and aCBV values in the bilateral amygdala were compared among the three groups. Correlation analyses between cerebral perfusion parameters and clinical variables were performed.Compared with HC participants, patients with CM were found to have increased CBF and aCBV values in the left amygdala, as well as increased CBF values in the right amygdala (all P < 0.05). There were no significant differences of CBF and aCBV values in the bilateral amygdala between the HC and EM groups, the EM and CM groups, as well as the CM without and with MOH groups (all P > 0.05). In patients with CM, the increased perfusion parameters of bilateral amygdala were positively correlated with MIDAS score after adjustments for age, sex, and body mass index (BMI).Hyperperfusion of bilateral amygdala might provide potential hemodynamics evidence in the neurolimbic pain network of CM.

  View details for DOI 10.1186/s10194-023-01668-0

  View details for PubMedID 37848831

  View details for PubMedCentralID PMC10583377

• Alterations in regional homogeneity and multiple frequency amplitudes of low-frequency fluctuation in patients with new daily persistent headache: a resting-state functional magnetic resonance imaging study. The journal of headache and pain Zhang, X., Wang, W., Bai, X., Mei, Y., Tang, H., Yuan, Z., Zhang, X., Li, Z., Zhang, P., Hu, Z., Zhang, Y., Yu, X., Sui, B., Wang, Y. 2023; 24 (1): 14

  Abstract

  New daily persistent headache (NPDH) is a rare primary headache that is highly disabling. The pathophysiology of NDPH is still unclear, and we aimed to reveal the underlying mechanism of NDPH through functional magnetic resonance imaging (fMRI) analysis.In this cross-sectional study, thirty patients with NDPH and 30 healthy controls (HCs) were recruited. The blood oxygen level-dependent (BOLD) sequences of all participants were obtained using the GE 3.0 T system. We performed ReHo, ALFF (conventional band: 0.01-0.08 Hz, slow-5: 0.01-0.027 Hz, slow-4: 0.027-0.073 Hz) and seed-based to the whole brain functional connectivity (FC) analysis in the NDPH and HC groups. The sex difference analysis of ReHo, ALFF, and FC values was conducted in the NDPH group. We also conducted Pearson's correlation analysis between ReHo, ALFF, FC values and clinical characteristics (pain intensity, disease duration, HIT-6, GAD-7, PHQ-9, and PSQI scores).Both increased ReHo (PFWE-corr = 0.012) and ALFF values (0.01-0.08 Hz, PFWE-corr = 0.009; 0.027-0.073 Hz, PFWE-corr =0.044) of the left middle occipital gyrus (MOG_L) were found in the NDPH group compared to the HC group. There was no significant difference in FC maps between the two groups. Compared to the HC group, no difference was found in ReHo (p = 0.284), ALFF (p = 0.246), and FC (p = 0.118) z scores of the MOG_L in the NDPH group. There was also no sex difference in ReHo (p = 0.288), ALFF (p = 0.859), or FC z score (p = 0.118) of the MOG_L in patients with NDPH. There was no correlation between ReHo, ALFF, FC z scores and clinical characteristics after Bonferroni correction (p < 0.05/18).Patients with NDPH may have abnormal activation of the visual system. Abnormal visual activation may occur mainly in higher frequency band of the classical band. No sex differences in brain activity were found in patients with NDPH.

  View details for DOI 10.1186/s10194-023-01543-y

  View details for PubMedID 36814220

  View details for PubMedCentralID PMC9946707

• Technical note: Revised projections onto convex sets reconstruction of multi-shot diffusion-weighted imaging. Medical physics Hu, Z., Zhang, Z., Ma, X., Jing, J., Guo, H. 2023; 50 (2): 980-992

  Abstract

  High-resolution diffusion-weighted imaging (DWI) is usually achieved through multi-shot acquisitions and parallel imaging-based reconstructions. Multiple POCS (projections onto convex sets) based algorithms have been proposed for DWI reconstructions. However, the slow convergence of POCS and the suboptimal quality of the reconstructed images limit their applications.In this study, a revised POCS algorithm for multi-shot DWI reconstruction is proposed based on FISTA (fast iterative shrinkage-thresholding algorithm) to achieve faster convergence and higher accuracy.In FISTA, the next iteration is computed based on two previous iterations, instead of only the previous one, to improve the convergence speed. This scheme is adopted into the relevant POCS-based algorithms, including POCSENSE (POCS-based sensitivity-encoding), POCSMUSE (POCS-based multiplexed sensitivity-encoding), iPOCSMUSE (iterative POCSMUSE), and POCS-ICE (POCS-enhanced inherent correction of motion-induced phase errors) to address the slow convergence problem. Simulations and in vivo experiments were performed to evaluate the performance of the proposed method.Experimental results show that the proposed method enables faster convergence compared to the original POCS. For example, for a spiral DWI simulation using eight-shot interleaves and having SNR of 20 dB, the iteration number needed for the revised POCS-ICE decreases by about 70% to achieve approximately the same nRMSE level as POCS-ICE. Additionally, it improves image quality in terms of fewer artifacts compared with the original POCS.The revised DWI reconstruction methods can achieve higher convergence rates than the original POCS-based algorithms and higher image quality with the same iteration numbers. As such, the proposed method can serve as a practical and efficient reconstruction method for multi-shot DWI.

  View details for DOI 10.1002/mp.16146

  View details for PubMedID 36464912

• Changes in gamma-aminobutyric acid and glutamate/glutamine levels in the right thalamus of patients with episodic and chronic migraine: A proton magnetic resonance spectroscopy study. Headache Zhang, X., Wang, W., Bai, X., Zhang, Y., Yuan, Z., Tang, H., Zhang, X., Li, Z., Zhang, P., Hu, Z., Zhang, Y., Yu, X., Man, X., Sui, B., Wang, Y. 2023; 63 (1): 104-113

  Abstract

  To explore gamma-aminobutyric acid (GABA) and glutamate/glutamine (Glx) levels in the right thalamus of patients with episodic migraine (EM) and chronic migraine (CM) and their effects on the chronification of migraine.Migraine affects approximately 1 billion people worldwide, with 2.5%-3% of people with EM progressing to CM each year. Magnetic resonance spectroscopy studies have revealed altered GABA and Glx levels in the thalamus of patients with migraine without aura, but these neurometabolic concentrations are underexplored in the thalamus of patients with CM.In this cross-sectional study, patients with EM and CM were recruited. Mescher-Garwood point resolved spectroscopy sequence was used to acquire neurotransmitter concentrations in the right thalamus of patients with EM and CM and matched healthy controls (HCs).A total of 26 patients (EM, n = 11; CM, n = 15) and 16 age- and sex-matched HCs were included in the analysis. There were significantly lower GABA+/Water levels in the right thalamus of the CM group (mean ± standard deviation: 2.27 ± 0.4 [institutional units]) than that of the HC group (2.74 ± 0.4) (p = 0.026; mean difference [MD] = -0.5 [i.u.]), and lower Glx/Cr levels in the EM group (mean ± SD: 0.11 ± < 0.1) than in the HCs (0.13 ± < 0.1) and CM group (0.13 ± < 0.1) (p = 0.023, MD < -0.1, and p = 0.034, MD < -0.1, respectively). The GABA+/Glx ratio was lower in the CM group (mean ± SD: 0.38 ± 0.1) compared to the EM group (0.47 ± 0.1) (p = 0.024; MD = -0.1). The area under the curve for GABA+/Water levels in differentiating patients with CM from HCs was 0.83 (95% confidence interval 0.68, 0.98; p = 0.004). Correlation analyses within the migraine group revealed no significant correlation between metabolite concentration levels and headache characteristics after Bonferroni correction.Reduced GABA+/Water levels and imbalance of excitation/inhibition in the right thalamus may contribute to migraine chronification.

  View details for DOI 10.1111/head.14449

  View details for PubMedID 36651572

• Cerebral perfusion variance in new daily persistent headache and chronic migraine: an arterial spin-labeled MR imaging study. The journal of headache and pain Bai, X., Wang, W., Zhang, X., Hu, Z., Zhang, Y., Li, Z., Zhang, X., Yuan, Z., Tang, H., Zhang, Y., Yu, X., Zhang, P., Wang, Y., Sui, B. 2022; 23 (1): 156

  Abstract

  New daily persistent headache (NDPH) and chronic migraine (CM) are two different types of headaches that might involve vascular dysregulation. There is still a lack of clarity about altered brain perfusion in NDPH and CM. This study aimed to investigate the cerebral perfusion variances of NDPH and CM using multi-delay pseudo-continuous arterial spin-labeled magnetic resonance imaging (pCASL-MRI).Fifteen patients with NDPH, 18 patients with CM, and 15 age- and sex-matched healthy controls (HCs) were included. All participants underwent 3D multi-delay pCASL-MRI to obtain cerebral perfusion data, including arrival-time-corrected cerebral blood flow (CBF) and arterial cerebral blood volume (aCBV). The automated anatomical labeling atlas 3 (AAL3) was used to parcellate 170 brain regions. The CBF and aCBV values in each brain region were compared among the three groups. Correlation analyses between cerebral perfusion parameters and clinical variables were performed.Compared with HC participants, patients with NDPH were found to have decreased CBF and aCBV values in multiple regions in the right hemisphere, including the right posterior orbital gyrus (OFCpost.R), right middle occipital gyrus (MOG.R), and ventral anterior nucleus of right thalamus (tVA.R), while patients with CM showed increased CBF and aCBV values presenting in the ventral lateral nucleus of left thalamus (tVL.L) and right thalamus (tVL.R) compared with HCs (all p < 0.05). In patients with NDPH, after age and sex adjustment, the increased aCBV values of IFGorb. R were positively correlated with GAD-7 scores; and the increased CBF and aCBV values of tVA.R were positively correlated with disease duration.The multi-delay pCASL technique can detect cerebral perfusion variation in patients with NDPH and CM. The cerebral perfusion changes may suggest different variations between NDPH and CM, which might provide hemodynamic evidence of these two types of primary headaches.

  View details for DOI 10.1186/s10194-022-01532-7

  View details for PubMedID 36482334

  View details for PubMedCentralID PMC9733035

• Gamma-aminobutyric acid and glutamate/glutamine levels in the dentate nucleus and periaqueductal gray with episodic and chronic migraine: a proton magnetic resonance spectroscopy study. The journal of headache and pain Wang, W., Zhang, X., Bai, X., Zhang, Y., Yuan, Z., Tang, H., Li, Z., Hu, Z., Zhang, Y., Yu, X., Sui, B., Wang, Y. 2022; 23 (1): 83

  Abstract

  The pathogenesis of migraine chronification remains unclear. Functional and structural magnetic resonance imaging studies have shown impaired functional and structural alterations in the brains of patients with chronic migraine. The cerebellum and periaqueductal gray (PAG) play pivotal roles in the neural circuits of pain conduction and analgesia in migraine. However, few neurotransmitter metabolism studies of these migraine-associated regions have been performed. To explore the pathogenesis of migraine chronification, we measured gamma-aminobutyric acid (GABA) and glutamate/glutamine (Glx) levels in the dentate nucleus (DN) and PAG of patients with episodic and chronic migraine and healthy subjects.Using the MEGA-PRESS sequence and a 3-Tesla magnetic resonance scanner (Signa Premier; GE Healthcare, Chicago, IL, USA), we obtained DN and PAG metabolite concentrations from patients with episodic migraine (n = 25), those with chronic migraine (n = 24), and age-matched and sex-matched healthy subjects (n = 16). Patients with chronic migraine were further divided into those with (n = 12) and without (n = 12) medication overuse headache. All scans were performed at the Beijing Tiantan Hospital, Capital Medical University.We found that patients with chronic migraine had significantly lower levels of GABA/water (p = 0.011) and GABA/creatine (Cr) (p = 0.026) in the DN and higher levels of Glx/water (p = 0.049) in the PAG than healthy controls. In all patients with migraine, higher GABA levels in the PAG were significantly associated with poorer sleep quality (GABA/water: r = 0.515, p = 0.017, n = 21; GABA/Cr: r = 0.522, p = 0.015, n = 21). Additionally, a lower Glx/Cr ratio in the DN may be associated with more severe migraine disability (r = -0.425, p = 0.055, n = 20), and lower GABA/water (r = -0.424, p = 0.062, n = 20) and Glx/Water (r = -0.452, p = 0.045, n = 20) may be associated with poorer sleep quality.Neurochemical levels in the DN and PAG may provide evidence of the pathological mechanisms of migraine chronification. Correlations between migraine characteristics and neurochemical levels revealed the pathological mechanisms of the relevant characteristics.

  View details for DOI 10.1186/s10194-022-01452-6

  View details for PubMedID 35840907

  View details for PubMedCentralID PMC9287958

• Deep learning-enhanced T1 mapping with spatial-temporal and physical constraint. Magnetic resonance in medicine Li, Y., Wang, Y., Qi, H., Hu, Z., Chen, Z., Yang, R., Qiao, H., Sun, J., Wang, T., Zhao, X., Guo, H., Chen, H. 2021; 86 (3): 1647-1661

  Abstract

  To propose a reconstruction framework to generate accurate T1 maps for a fast MR T1 mapping sequence.A deep learning-enhanced T1 mapping method with spatial-temporal and physical constraint (DAINTY) was proposed. This method explicitly imposed low-rank and sparsity constraints on the multiframe T1 -weighted images to exploit the spatial-temporal correlation. A deep neural network was used to efficiently perform T1 mapping as well as denoise and reduce undersampling artifacts. Additionally, the physical constraint was used to build a bridge between low-rank and sparsity constraint and deep learning prior, so the benefits of constrained reconstruction and deep learning can be both available. The DAINTY method was trained on simulated brain data sets, but tested on real acquired phantom, 6 healthy volunteers, and 7 atherosclerosis patients, compared with the narrow-band k-space-weighted image contrast filter conjugate-gradient SENSE (NK-CS) method, kt-sparse-SENSE (kt-SS) method, and low-rank plus sparsity (L+S) method with least-squares T1 fitting and direct deep learning mapping.The DAINTY method can generate more accurate T1 maps and higher-quality T1 -weighted images compared with other methods. For atherosclerosis patients, the intraplaque hemorrhage can be successfully detected. The computation speed of DAINTY was 10 times faster than traditional methods. Meanwhile, DAINTY can reconstruct images with comparable quality using only 50% of k-space data.The proposed method can provide accurate T1 maps and good-quality T1 -weighted images with high efficiency.

  View details for DOI 10.1002/mrm.28793

  View details for PubMedID 33821529

• High-fidelity diffusion tensor imaging of the cervical spinal cord using point-spread-function encoded EPI. NeuroImage Li, S., Wang, Y., Hu, Z., Guan, L., Hai, Y., Zhang, H., He, L., Jiang, W., Guo, H. 2021; 236: 118043

  Abstract

  Diffusion tensor imaging (DTI) of the spinal cord is technically challenging due to the size of its structure and susceptibility-induced field inhomogeneity, which impedes clinical applications. This study aimed to achieve high-fidelity spinal cord DTI with reasonable SNR and practical acquisition efficiency. Particularly, a distortion-free multi-shot EPI technique, namely point-spread-function encoded EPI (PSF-EPI), was adopted for diffusion imaging of the cervical spinal cord (CSC). The shot number can be reduced to six for sagittal scans through titled-CAIPI acceleration and partial Fourier undersampling, consequently rendering this technique beneficial in clinics. Fifteen healthy volunteers and seven patients with metallic implants underwent sagittal scans using tilted-CAIPI PSF-EPI at 3T. Unsuppressed fat signals were further removed by retrospective water/fat separation using the intrinsic chemical-shift encoded signals. Compared with multi-shot interleaved EPI method, highly accelerated PSF-EPI method provided evidently improved distortion reduction and higher consistency with anatomical references even with metallic implants. Additionally, axial DTI scans using PSF-EPI were also evaluated quantitatively, and the measured DTI metrics are similar to those obtained from the zonal oblique multi-slice EPI (ZOOM-EPI) method and reported values. The high anatomical consistency, practical scan time and quantitative reliability indicate PSF-EPI's clinical potential for CSC diffusion imaging.

  View details for DOI 10.1016/j.neuroimage.2021.118043

  View details for PubMedID 33857617

• Distortion correction of single-shot EPI enabled by deep-learning. NeuroImage Hu, Z., Wang, Y., Zhang, Z., Zhang, J., Zhang, H., Guo, C., Sun, Y., Guo, H. 2020; 221: 117170

  Abstract

  A distortion correction method for single-shot EPI was proposed. Point-spread-function encoded EPI (PSF-EPI) images were used as the references to correct traditional EPI images based on deep neural network.The PSF-EPI method can obtain distortion-free echo planar images. In this study, a 2D U-net based network was trained to achieve the distortion correction of single-shot EPI (SS-EPI) images, using PSF-EPI images as targets in the training stage. Anatomical T2W-TSE images were also fed into the network to improve the quality of the results. The applications in diffusion-weighted images were used as examples in this work. The network was trained on data acquired on healthy volunteers and tested on data of both healthy volunteers and patients. The corrected EPI images from the proposed method were also compared with those from field-mapping and top-up based distortion correction methods.Experimental results showed that the proposed method can correct for EPI distortions better than both the field-mapping and top-up based methods, and the results were close to the distortion-free images from PSF-EPI. Additionally, inclusion of T2W-TSE images helped improve distortion correction of the SS-EPI images without contaminating the output noticeably. The experiments with patients and different MRI platforms demonstrated the generalization feasibility of the proposed method preliminarily.Through the correction of diffusion-weighted images, the proposed deep-learning based method was demonstrated to have the feasibility to correct for the distortion of EPI images.

  View details for DOI 10.1016/j.neuroimage.2020.117170

  View details for PubMedID 32682096

• Referenceless multi-channel signal combination: A demonstration in chemical-shift-encoded water-fat imaging. Magnetic resonance in medicine Liu, S., Wu, P., Liu, H., Hu, Z., Guo, H. 2020; 83 (5): 1810-1824

  Abstract

  Without explicit coil sensitivity information acquired by means of a reference body coil, multi-channel signal combination for water-fat separation (WFS) can be challenging due to channel-dependent phase offsets and chemical-shift dependent phase shifts. This study aims to develop a referenceless, robust, accurate, and fast channel combination method for WFS.A dual-step multi-channel combination method is proposed. In the first step, channel-dependent phase offsets are estimated with a preliminary WFS estimation. In the second step, the multi-channel data are combined after removing phase offsets. Thereafter, WFS is performed to obtain final results. Numerical simulations (4-64 coils) and in vivo experiments (8, 16, 28 coils) at 3T field strength are conducted to compare the proposed method to previous methods. Channel combination with a body-coil scan serves as the reference for in vivo experiments.The proposed method estimates channel-dependent phase offsets accurately. It shows improved robustness to phase singularities than weighted mean and adaptive reconstruction. It is faster than adaptive reconstruction (e.g., 25.45 versus 46.34 s with 28 coils) and the channel-by-channel WFS method (e.g., 21.77 versus 50.04 s with 8 coils). It provides comparable fat quantification accuracy to the reference under various reasonable signal-to-noise ratio conditions (e.g., Pearson correlation coefficient r = 0.981 with P < 0.01, for in vivo fat fractions using flip angle = 10°).The proposed referenceless channel combination method may be beneficial to both qualitative and quantitative water-fat imaging.

  View details for DOI 10.1002/mrm.28028

  View details for PubMedID 31605554

• Deep learning-based MR fingerprinting ASL ReconStruction (DeepMARS) MAGNETIC RESONANCE IN MEDICINE Zhang, Q., Su, P., Chen, Z., Liao, Y., Chen, S., Guo, R., Qi, H., Li, X., Zhang, X., Hu, Z., Lu, H., Chen, H. 2020; 84 (2): 1024–34

  Abstract

  To develop a reproducible and fast method to reconstruct MR fingerprinting arterial spin labeling (MRF-ASL) perfusion maps using deep learning.A fully connected neural network, denoted as DeepMARS, was trained using simulation data and added Gaussian noise. Two MRF-ASL models were used to generate the simulation data, specifically a single-compartment model with 4 unknowns parameters and a two-compartment model with 7 unknown parameters. The DeepMARS method was evaluated using MRF-ASL data from healthy subjects (N = 7) and patients with Moymoya disease (N = 3). Computation time, coefficient of determination (R2 ), and intraclass correlation coefficient (ICC) were compared between DeepMARS and conventional dictionary matching (DM). The relationship between DeepMARS and Look-Locker PASL was evaluated by a linear mixed model.Computation time per voxel was <0.5 ms for DeepMARS and >4 seconds for DM in the single-compartment model. Compared with DM, the DeepMARS showed higher R2 and significantly improved ICC for single-compartment derived bolus arrival time (BAT) and two-compartment derived cerebral blood flow (CBF) and higher or similar R2 /ICC for other parameters. In addition, the DeepMARS was significantly correlated with Look-Locker PASL for BAT (single-compartment) and CBF (two-compartment). Moreover, for Moyamoya patients, the location of diminished CBF and prolonged BAT shown in DeepMARS was consistent with the position of occluded arteries shown in time-of-flight MR angiography.Reconstruction of MRF-ASL with DeepMARS is faster and more reproducible than DM.

  View details for DOI 10.1002/mrm.28166

  View details for Web of Science ID 000510713500001

  View details for PubMedID 32017236

• Predicting the Post-therapy Severity Level (UPDRS-III) of Patients With Parkinson's Disease After Drug Therapy by Using the Dynamic Connectivity Efficiency of fMRI. Frontiers in neurology Li, X., Xiong, Y., Liu, S., Zhou, R., Hu, Z., Tong, Y., He, L., Niu, Z., Ma, Y., Guo, H. 2019; 10: 668

  Abstract

  Parkinson's disease (PD) is a multi-systemic disease in the brain arising from the dysfunction of several neural networks. The diagnosis and treatment of PD have gained more attention for clinical researchers. While there have been many fMRI studies about functional topological changes of PD patients, whether the dynamic changes of functional connectivity can predict the drug therapy effect is still unclear. The primary objective of this study was to assess whether large-scale functional efficiency changes of topological network are detectable in PD patients, and to explore whether the severity level (UPDRS-III) after drug treatment can be predicted by the pre-treatment resting-state fMRI (rs-fMRI). Here, we recruited 62 Parkinson's disease patients and calculated the dynamic nodal efficiency networks based on rs-fMRI. With connectome-based predictive models using the least absolute shrinkage and selection operator, we demonstrated that the dynamic nodal efficiency properties predict drug therapy effect well. The contributed regions for the prediction include hippocampus, post-central gyrus, cingulate gyrus, and orbital gyrus. Specifically, the connections between hippocampus and cingulate gyrus, hippocampus and insular gyrus, insular gyrus, and orbital gyrus are positively related to the recovery (post-therapy severity level) after drug therapy. The analysis of these connection features may provide important information for clinical treatment of PD patients.

  View details for DOI 10.3389/fneur.2019.00668

  View details for PubMedID 31354605

  View details for PubMedCentralID PMC6636605

• Water/fat separation for distortion-free EPI with point spread function encoding. Magnetic resonance in medicine Hu, Z., Wang, Y., Dong, Z., Guo, H. 2019; 82 (1): 251-262

  Abstract

  Effective removal of chemical-shift artifacts in echo-planar imaging (EPI) is a challenging problem especially with severe field inhomogeneity. This study aims to develop a reliable water/fat separation technique for point spread function (PSF) encoded EPI (PSF-EPI) by using its intrinsic multiple echo-shifted images.EPI with PSF encoding can achieve distortion-free imaging and can be highly accelerated using the tilted-CAIPI technique. In this study, the chemical-shift encoding existing in the intermediate images with different time shifts of PSF-EPI is used for water/fat separation, which is conducted with latest water/fat separation algorithms. The method was tested in T1-weighted, T2-weighted, and diffusion weighted imaging in healthy volunteers.The ability of the proposed method to separate water/fat using intrinsic PSF-EPI signals without extra scans was demonstrated through in vivo T1-weighted, T2-weighted, and diffusion weighted imaging experiments. By exploring different imaging contrasts and regions, the results show that this PSF-EPI based method can separate water/fat and remove fat residues robustly.By using the intrinsic signals of PSF-EPI for water/fat separation, fat signals can be effectively suppressed in EPI even with severe field inhomogeneity. This water/fat separation method for EPI can be extended to multiple image contrasts. The distortion-free PSF-EPI technique, thus, has the potential to provide anatomical and functional images with high-fidelity and practical acquisition efficiency.

  View details for DOI 10.1002/mrm.27717

  View details for PubMedID 30847991

• Phase-updated regularized SENSE for navigator-free multishot diffusion imaging. Magnetic resonance in medicine Hu, Z., Ma, X., Truong, T. K., Song, A. W., Guo, H. 2017; 78 (1): 172-181

  Abstract

  Either SENSE+CG or POCS-ICE methods can be used to correct for motion-induced phase errors in navigator-free multishot diffusion imaging. SENSE+CG has the advantage of a fast convergence, however, occasionally the convergence can be unstable, thus degrading the image quality. POCS-ICE has a stable convergence and can be used with a high number of shots, but its convergence is slow, which limits its practical usage. The study here proposes an improved method based on both SENSE+CG and POCS-ICE, called Phase-updated Regularized SENSE (PR-SENSE), for navigator-free multishot diffusion imaging.In PR-SENSE, a total variation regularization method is used to solve the SENSE inverse problem instead of the conjugate gradient method used in SENSE+CG. This method is implemented by using a lagged diffusivity fixed point iteration algorithm. Additionally, the phase is updated during the iteration process to improve the image accuracy.Simulations and in vivo experiments demonstrated that PR-SENSE can successfully correct for the motion-induced phase errors in multi-shot DWI. It integrates the advantages of SENSE+CG and POCS-ICE, resulting in a fast and stable convergence with improved image quality.Given its advantages, PR-SENSE is a significant improvement over other methods for navigator-free high-resolution DWI. Magn Reson Med 78:172-181, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

  View details for DOI 10.1002/mrm.26361

  View details for PubMedID 27520840