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Brendstrup-Brix K, Ulv Larsen SM, Lee HH, Knudsen GM. Perivascular space diffusivity and brain microstructural measures are associated with circadian time and sleep quality. J Sleep Res 2024:e14226. [PMID: 38676409 DOI: 10.1111/jsr.14226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
The glymphatic system is centred around brain cerebrospinal fluid flow and is enhanced during sleep, and the synaptic homeostasis hypothesis proposes that sleep acts on brain microstructure by selective synaptic downscaling. While so far primarily studied in animals, we here examine in humans if brain diffusivity and microstructure is related to time of day, sleep quality and cognitive performance. We use diffusion weighted images from 916 young healthy individuals, aged between 22 and 37 years, collected as part of the Human Connectome Project to assess diffusion tensor image analysis along the perivascular space index, white matter fractional anisotropy, intra-neurite volume fraction and extra-neurite mean diffusivity. Next, we examine if these measures are associated with circadian time of acquisition, the Pittsburgh Sleep Quality Index (high scores correspond to low sleep quality) and age-adjusted cognitive function total composite score. Consistent with expectations, we find that diffusion tensor image analysis along the perivascular space index and orbitofrontal grey matter extra-neurite mean diffusivity are negatively and white matter fractional anisotropy positively correlated with circadian time. Further, we find that grey matter intra-neurite volume fraction correlates positively with Pittsburgh Sleep Quality Index, and that this correlation is driven by sleep duration. Finally, we find positive correlations between grey matter intra-neurite volume fraction and cognitive function total composite score, as well as negative interaction effects between cognitive function total composite score and Pittsburgh Sleep Quality Index on grey matter intra-neurite volume fraction. Our findings propose that perivascular flow is under circadian control and that sleep downregulates the intra-neurite volume in healthy adults with positive impact on cognitive function.
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Affiliation(s)
- Kristoffer Brendstrup-Brix
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara Marie Ulv Larsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Gitte Moos Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Li Z, Li Z, Bilgic B, Lee HH, Ying K, Huang SY, Liao H, Tian Q. DIMOND: DIffusion Model OptimizatioN with Deep Learning. Adv Sci (Weinh) 2024:e2307965. [PMID: 38634608 DOI: 10.1002/advs.202307965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 02/09/2024] [Indexed: 04/19/2024]
Abstract
Diffusion magnetic resonance imaging is an important tool for mapping tissue microstructure and structural connectivity non-invasively in the in vivo human brain. Numerous diffusion signal models are proposed to quantify microstructural properties. Nonetheless, accurate estimation of model parameters is computationally expensive and impeded by image noise. Supervised deep learning-based estimation approaches exhibit efficiency and superior performance but require additional training data and may be not generalizable. A new DIffusion Model OptimizatioN framework using physics-informed and self-supervised Deep learning entitled "DIMOND" is proposed to address this problem. DIMOND employs a neural network to map input image data to model parameters and optimizes the network by minimizing the difference between the input acquired data and synthetic data generated via the diffusion model parametrized by network outputs. DIMOND produces accurate diffusion tensor imaging results and is generalizable across subjects and datasets. Moreover, DIMOND outperforms conventional methods for fitting sophisticated microstructural models including the kurtosis and NODDI model. Importantly, DIMOND reduces NODDI model fitting time from hours to minutes, or seconds by leveraging transfer learning. In summary, the self-supervised manner, high efficacy, and efficiency of DIMOND increase the practical feasibility and adoption of microstructure and connectivity mapping in clinical and neuroscientific applications.
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Affiliation(s)
- Zihan Li
- School of Biomedical Engineering, Tsinghua University, Beijing, 100084, P. R. China
| | - Ziyu Li
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Harvard Medical School, Boston, MA, 02129, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Harvard Medical School, Boston, MA, 02129, USA
| | - Kui Ying
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Harvard Medical School, Boston, MA, 02129, USA
| | - Hongen Liao
- School of Biomedical Engineering, Tsinghua University, Beijing, 100084, P. R. China
| | - Qiyuan Tian
- School of Biomedical Engineering, Tsinghua University, Beijing, 100084, P. R. China
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Dong Z, Reese TG, Lee HH, Huang SY, Polimeni JR, Wald LL, Wang F. Romer-EPTI: rotating-view motion-robust super-resolution EPTI for SNR-efficient distortion-free in-vivo mesoscale dMRI and microstructure imaging. bioRxiv 2024:2024.01.26.577343. [PMID: 38352481 PMCID: PMC10862730 DOI: 10.1101/2024.01.26.577343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Purpose To overcome the major challenges in dMRI acquisition, including low SNR, distortion/blurring, and motion vulnerability. Methods A novel Romer-EPTI technique is developed to provide distortion-free dMRI with significant SNR gain, high motion-robustness, sharp spatial resolution, and simultaneous multi-TE imaging. It introduces a ROtating-view Motion-robust supEr-Resolution technique (Romer) combined with a distortion/blurring-free EPTI encoding. Romer enhances SNR by a simultaneous multi-thick-slice acquisition with rotating-view encoding, while providing high motion-robustness through a motion-aware super-resolution reconstruction, which also incorporates slice-profile and real-value diffusion, to resolve high-isotropic-resolution volumes. The in-plane encoding is performed using distortion/blurring-free EPTI, which further improves effective spatial resolution and motion robustness by preventing not only T2/T2*-blurring but also additional blurring resulting from combining encoded volumes with inconsistent geometries caused by dynamic distortions. Self-navigation was incorporated to enable efficient phase correction. Additional developments include strategies to address slab-boundary artifacts, achieve minimal TE for SNR gain at 7T, and achieve high robustness to strong phase variations at high b-values. Results Using Romer-EPTI, we demonstrate distortion-free whole-brain mesoscale in-vivo dMRI at both 3T (500-μm-iso) and 7T (485-μm-iso) for the first time, with high SNR efficiency (e.g., 25 × ), and high image quality free from distortion and slab-boundary artifacts with minimal blurring. Motion experiments demonstrate Romer-EPTI's high motion-robustness and ability to recover sharp images in the presence of motion. Romer-EPTI also demonstrates significant SNR gain and robustness in high b-value (b=5000s/mm2) and time-dependent dMRI. Conclusion Romer-EPTI significantly improves SNR, motion-robustness, and image quality, providing a highly efficient acquisition for high-resolution dMRI and microstructure imaging.
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Affiliation(s)
- Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Timothy G. Reese
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Susie Y. Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Jonathan R. Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Lawrence L. Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Health Sciences and Technology, MIT, Cambridge, Massachusetts, USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
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Lee HH, Tian Q, Sheft M, Coronado-Leija R, Ramos-Llorden G, Abdollahzadeh A, Fieremans E, Novikov DS, Huang SY. The effects of axonal beading and undulation on axonal diameter estimation from diffusion MRI: Insights from simulations in human axons segmented from three-dimensional electron microscopy. NMR Biomed 2024; 37:e5087. [PMID: 38168082 PMCID: PMC10942763 DOI: 10.1002/nbm.5087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/19/2023] [Accepted: 11/21/2023] [Indexed: 01/05/2024]
Abstract
The increasing availability of high-performance gradient systems in human MRI scanners has generated great interest in diffusion microstructural imaging applications such as axonal diameter mapping. Practically, sensitivity to axon diameter in diffusion MRI is attained at strong diffusion weightings b , where the deviation from the expected 1 / b scaling in white matter yields a finite transverse diffusivity, which is then translated into an axon diameter estimate. While axons are usually modeled as perfectly straight, impermeable cylinders, local variations in diameter (caliber variation or beading) and direction (undulation) are known to influence axonal diameter estimates and have been observed in microscopy data of human axons. In this study, we performed Monte Carlo simulations of diffusion in axons reconstructed from three-dimensional electron microscopy of a human temporal lobe specimen using simulated sequence parameters matched to the maximal gradient strength of the next-generation Connectome 2.0 human MRI scanner ( ≲ 500 mT/m). We show that axon diameter estimation is accurate for nonbeaded, nonundulating fibers; however, in fibers with caliber variations and undulations, the axon diameter is heavily underestimated due to caliber variations, and this effect overshadows the known overestimation of the axon diameter due to undulations. This unexpected underestimation may originate from variations in the coarse-grained axial diffusivity due to caliber variations. Given that increased axonal beading and undulations have been observed in pathological tissues, such as traumatic brain injury and ischemia, the interpretation of axon diameter alterations in pathology may be significantly confounded.
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Affiliation(s)
- Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Maxina Sheft
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard–MIT Health Sciences and Technology, Cambridge, Massachusetts, USA
| | - Ricardo Coronado-Leija
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, New York, USA
| | - Gabriel Ramos-Llorden
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Ali Abdollahzadeh
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, New York, USA
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, New York, USA
| | - Dmitry S. Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, New York, USA
| | - Susie Y. Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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Chen J, Ades-Aron B, Lee HH, Mehrin S, Pang M, Novikov DS, Veraart J, Fieremans E. Optimization and Validation of the DESIGNER dMRI preprocessing pipeline in white matter aging. ArXiv 2024:arXiv:2305.14445v2. [PMID: 37292482 PMCID: PMC10246085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Various diffusion MRI (dMRI) preprocessing pipelines are currently available to yield more accurate diffusion parameters. Here, we evaluated accuracy and robustness of the optimized Diffusion parameter EStImation with Gibbs and NoisE Removal (DESIGNER) pipeline in a large clinical dMRI dataset and using ground truth phantoms. DESIGNER has been modified to improve denoising and target Gibbs ringing for partial Fourier acquisitions. We compared the revisited DESIGNER (Dv2) (including denoising, Gibbs removal, correction for motion, EPI distortion, and eddy currents) against the original DESIGNER (Dv1) pipeline, minimal preprocessing (including correction for motion, EPI distortion, and eddy currents only), and no preprocessing on a large clinical dMRI dataset of 524 control subjects with ages between 25 and 75 years old. We evaluated the effect of specific processing steps on age correlations in white matter with DTI and DKI metrics. We also evaluated the added effect of minimal Gaussian smoothing to deal with noise and to reduce outliers in parameter maps compared to DESIGNER (Dv2)'s noise removal method. Moreover, DESIGNER (Dv2)'s updated noise and Gibbs removal methods were assessed using ground truth dMRI phantom to evaluate accuracy. Results show age correlation in white matter with DTI and DKI metrics were affected by the preprocessing pipeline, causing systematic differences in absolute parameter values and loss or gain of statistical significance. Both in clinical dMRI and ground truth phantoms, DESIGNER (Dv2) pipeline resulted in the smallest number of outlier voxels and improved accuracy in DTI and DKI metrics as noise was reduced and Gibbs removal was improved. Thus, DESIGNER (Dv2) provides more accurate and robust DTI and DKI parameter maps as compared to no preprocessing or minimal preprocessing.
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Ramos-Llordén G, Park DJ, Kirsch JE, Scholz A, Keil B, Maffei C, Lee HH, Bilgic B, Edlow BL, Mekkaoui C, Yendiki A, Witzel T, Huang SY. Eddy current-induced artifact correction in high b-value ex vivo human brain diffusion MRI with dynamic field monitoring. Magn Reson Med 2024; 91:541-557. [PMID: 37753621 PMCID: PMC10842131 DOI: 10.1002/mrm.29873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 08/30/2023] [Accepted: 09/02/2023] [Indexed: 09/28/2023]
Abstract
PURPOSE To investigate whether spatiotemporal magnetic field monitoring can correct pronounced eddy current-induced artifacts incurred by strong diffusion-sensitizing gradients up to 300 mT/m used in high b-value diffusion-weighted (DW) EPI. METHODS A dynamic field camera equipped with 16 1 H NMR field probes was first used to characterize field perturbations caused by residual eddy currents from diffusion gradients waveforms in a 3D multi-shot EPI sequence on a 3T Connectom scanner for different gradient strengths (up to 300 mT/m), diffusion directions, and shots. The efficacy of dynamic field monitoring-based image reconstruction was demonstrated on high-gradient strength, submillimeter resolution whole-brain ex vivo diffusion MRI. A 3D multi-shot image reconstruction framework was developed that incorporated the nonlinear phase evolution measured with the dynamic field camera. RESULTS Phase perturbations in the readout induced by residual eddy currents from strong diffusion gradients are highly nonlinear in space and time, vary among diffusion directions, and interfere significantly with the image encoding gradients, changing the k-space trajectory. During the readout, phase modulations between odd and even EPI echoes become non-static and diffusion encoding direction-dependent. Superior reduction of ghosting and geometric distortion was achieved with dynamic field monitoring compared to ghosting reduction approaches such as navigator- and structured low-rank-based methods or MUSE followed by image-based distortion correction with the FSL tool "eddy." CONCLUSION Strong eddy current artifacts characteristic of high-gradient strength DW-EPI can be well corrected with dynamic field monitoring-based image reconstruction.
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Affiliation(s)
- Gabriel Ramos-Llordén
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Daniel J Park
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - John E Kirsch
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Alina Scholz
- Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany
| | - Boris Keil
- Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Marburg, Philipps University of Marburg, Marburg, Germany
| | - Chiara Maffei
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Brian L Edlow
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Choukri Mekkaoui
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | | | - Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Coronado-Leija R, Abdollahzadeh A, Lee HH, Coelho S, Ades-Aron B, Liao Y, Salo RA, Tohka J, Sierra A, Novikov DS, Fieremans E. Volume electron microscopy in injured rat brain validates white matter microstructure metrics from diffusion MRI. ArXiv 2024:arXiv:2310.04608v2. [PMID: 38259346 PMCID: PMC10802677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Biophysical modeling of diffusion MRI (dMRI) offers the exciting potential of bridging the gap between the macroscopic MRI resolution and microscopic cellular features, effectively turning the MRI scanner into a noninvasive in vivo microscope. In brain white matter, the Standard Model (SM) interprets the dMRI signal in terms of axon dispersion, intra- and extra-axonal water fractions and diffusivities. However, for SM to be fully applicable and correctly interpreted, it needs to be carefully evaluated using histology. Here, we perform a comprehensive histological validation of the SM parameters, by characterizing WM microstructure in sham and injured rat brains using volume (3d) electron microscopy (EM) and ex vivo dMRI. Sensitivity is evaluated by how close each SM metric is to its histological counterpart, and specificity by how independent it is from other, non-corresponding histological features. This comparison reveals that SM is sensitive and specific to microscopic properties, clearing the way for the clinical adoption of in vivo dMRI derived SM parameters as biomarkers for neurological disorders.
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Seriramulu VP, Suppiah S, Lee HH, Jang JH, Omar NF, Mohan SN, Ibrahim NSN, Azmi NHM, Buhari I, Ahmad U. Review of MR spectroscopy analysis and artificial intelligence applications for the detection of cerebral inflammation and neurotoxicity in Alzheimer's disease. Med J Malaysia 2024; 79:102-110. [PMID: 38287765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
INTRODUCTION Magnetic resonance spectroscopy (MRS) has an emerging role as a neuroimaging tool for the detection of biomarkers of Alzheimer's disease (AD). To date, MRS has been established as one of the diagnostic tools for various diseases such as breast cancer and fatty liver, as well as brain tumours. However, its utility in neurodegenerative diseases is still in the experimental stages. The potential role of the modality has not been fully explored, as there is diverse information regarding the aberrations in the brain metabolites caused by normal ageing versus neurodegenerative disorders. MATERIALS AND METHODS A literature search was carried out to gather eligible studies from the following widely sourced electronic databases such as Scopus, PubMed and Google Scholar using the combination of the following keywords: AD, MRS, brain metabolites, deep learning (DL), machine learning (ML) and artificial intelligence (AI); having the aim of taking the readers through the advancements in the usage of MRS analysis and related AI applications for the detection of AD. RESULTS We elaborate on the MRS data acquisition, processing, analysis, and interpretation techniques. Recommendation is made for MRS parameters that can obtain the best quality spectrum for fingerprinting the brain metabolomics composition in AD. Furthermore, we summarise ML and DL techniques that have been utilised to estimate the uncertainty in the machine-predicted metabolite content, as well as streamline the process of displaying results of metabolites derangement that occurs as part of ageing. CONCLUSION MRS has a role as a non-invasive tool for the detection of brain metabolite biomarkers that indicate brain metabolic health, which can be integral in the management of AD.
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Affiliation(s)
- V P Seriramulu
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia
| | - S Suppiah
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia.
| | - H H Lee
- METLiT Inc., Seoul, Republic of Korea
| | - J H Jang
- METLiT Inc., Seoul, Republic of Korea
| | - N F Omar
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia
| | - S N Mohan
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Psychiatry, 43400 Serdang, Selangor, Malaysia
| | - N S N Ibrahim
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia
| | - N H M Azmi
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia
| | - I Buhari
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Radiology, 43400 Serdang, Selangor, Malaysia
| | - U Ahmad
- Bauchi State University, Faculty of Basic Medical Sciences, Department of Anatomy, Molecular Genetics Informatics, Gadau, Nigeria
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Lee HH, Keerthivasan MB, Lemberskiy G, Zhang J, Fieremans E, Novikov DS. Universal Sampling Denoising (USD) for noise mapping and noise removal of non-Cartesian MRI. ArXiv 2023:arXiv:2311.16316v1. [PMID: 38076512 PMCID: PMC10705579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Random matrix theory (RMT) combined with principal component analysis has resulted in a widely used MPPCA noise mapping and denoising algorithm, that utilizes the redundancy in multiple acquisitions and in local image patches. RMT-based denoising relies on the uncorrelated identically distributed noise. This assumption breaks down after regridding of non-Cartesian sampling. Here we propose a Universal Sampling Denoising (USD) pipeline to homogenize the noise level and decorrelate the noise in non-Cartesian sampled k-space data after resampling to a Cartesian grid. In this way, the RMT approaches become applicable to MRI of any non-Cartesian k-space sampling. We demonstrate the denoising pipeline on MRI data acquired using radial trajectories, including diffusion MRI of a numerical phantom and ex vivo mouse brains, as well as in vivo $T_2$ MRI of a healthy subject. The proposed pipeline robustly estimates noise level, performs noise removal, and corrects bias in parametric maps, such as diffusivity and kurtosis metrics, and $T_2$ relaxation time. USD stabilizes the variance, decorrelates the noise, and thereby enables the application of RMT-based denoising approaches to MR images reconstructed from any non-Cartesian data. In addition to MRI, USD may also apply to other medical imaging techniques involving non-Cartesian acquisition, such as PET, CT, and SPECT.
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Wu D, Turnbill V, Lee HH, Wang X, Ba R, Walczak P, Martin LJ, Fieremans E, Novikov DS, Northington FJ, Zhang J. In vivo Mapping of Cellular Resolution Neuropathology in Brain Ischemia by Diffusion MRI. bioRxiv 2023:2023.08.08.552374. [PMID: 37609182 PMCID: PMC10441332 DOI: 10.1101/2023.08.08.552374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Non-invasive mapping of cellular pathology can provide critical diagnostic and prognostic information. Recent developments in diffusion MRI have produced new tools for examining tissue microstructure at a level well below the imaging resolution. Here, we report the use of diffusion time ( t )-dependent diffusion kurtosis imaging ( t DKI) to simultaneously assess the morphology and transmembrane permeability of cells and their processes in the context of pathological changes in hypoxic-ischemic brain (HI) injury. Through Monte Carlo simulations and cell culture organoid imaging, we demonstrate feasibility in measuring effective size and permeability changes based on the peak and tail of t DKI curves. In a mouse model of HI, in vivo imaging at 11.7T detects a marked shift of the t DKI peak to longer t in brain edema, suggesting swelling and beading associated with the astrocytic processes and neuronal neurites. Furthermore, we observed a faster decrease of the t DKI tail in injured brain regions, reflecting increased membrane permeability that was associated with upregulated water exchange upon astrocyte activation at acute stage as well as necrosis with disrupted membrane integrity at subacute stage. Such information, unavailable with conventional diffusion MRI at a single t, can predict salvageable tissues. For a proof-of-concept, t DKI at 3T on an ischemic stroke patient suggested increased membrane permeability in the stroke region. This work therefore demonstrates the potential of t DKI for in vivo detection of the pathological changes in microstructural morphology and transmembrane permeability after ischemic injury using a clinically translatable protocol.
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Lee HH, Tian Q, Sheft M, Coronado-Leija R, Ramos-Llorden G, Abdollahzadeh A, Fieremans E, Novikov DS, Huang SY. The influence of axonal beading and undulation on axonal diameter mapping. bioRxiv 2023:2023.04.19.537494. [PMID: 37131702 PMCID: PMC10153226 DOI: 10.1101/2023.04.19.537494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We consider the effect of non-cylindrical axonal shape on axonal diameter mapping with diffusion MRI. Practical sensitivity to axon diameter is attained at strong diffusion weightings b , where the deviation from the 1 / b scaling yields the finite transverse diffusivity, which is then translated into axon diameter. While axons are usually modeled as perfectly straight, impermeable cylinders, the local variations in diameter (caliber variation or beading) and direction (undulation) have been observed in microscopy data of human axons. Here we quantify the influence of cellular-level features such as caliber variation and undulation on axon diameter estimation. For that, we simulate the diffusion MRI signal in realistic axons segmented from 3-dimensional electron microscopy of a human brain sample. We then create artificial fibers with the same features and tune the amplitude of their caliber variations and undulations. Numerical simulations of diffusion in fibers with such tunable features show that caliber variations and undulations result in under- and over-estimation of axon diameters, correspondingly; this bias can be as large as 100%. Given that increased axonal beading and undulations have been observed in pathological tissues, such as traumatic brain injury and ischemia, the interpretation of axon diameter alterations in pathology may be significantly confounded.
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Affiliation(s)
- Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129,USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129,USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Maxina Sheft
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129,USA
- Harvard-MIT Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Ricardo Coronado-Leija
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY 10016, USA
| | - Gabriel Ramos-Llorden
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129,USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Ali Abdollahzadeh
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY 10016, USA
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY 10016, USA
| | - Dmitry S. Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
- Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY 10016, USA
| | - Susie Y. Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129,USA
- Harvard Medical School, Boston, MA 02115, USA
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12
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Mandija S, Ma C, Bai R, Feng L, Giganti F, Ianus A, Lee HH, Li F, Welton T, Calamante F. Walking with the ISMRM in the footprints of our MR history. Magn Reson Med 2023; 89:883-885. [PMID: 36353850 DOI: 10.1002/mrm.29488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/21/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Stefano Mandija
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Chao Ma
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ruiliang Bai
- Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Li Feng
- BioMedical Engineering and Imaging Institute (BMEII) and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Francesco Giganti
- Division of Surgery and Interventional Science, Faculty of Medical Sciences, University College London, London, UK
| | - Andrada Ianus
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Fei Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Thomas Welton
- National Neuroscience Institute, Singapore & Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Fernando Calamante
- School of Biomedical Engineering and Sydney Imaging, The University of Sydney, Sydney, Australia
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13
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Ramos-Llordén G, Park D, Kirsch JE, Scholz A, Keil B, Maffei C, Lee HH, Bilgiç B, Edlow BL, Mekkaoui C, Yendiki A, Witzel T, Huang SY. Eddy current-induced artifacts correction in high gradient strength diffusion MRI with dynamic field monitoring: demonstration in ex vivo human brain imaging. bioRxiv 2023:2023.02.15.528684. [PMID: 36824894 PMCID: PMC9948962 DOI: 10.1101/2023.02.15.528684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Purpose To demonstrate the advantages of spatiotemporal magnetic field monitoring to correct eddy current-induced artifacts (ghosting and geometric distortions) in high gradient strength diffusion MRI (dMRI). Methods A dynamic field camera with 16 NMR field probes was used to characterize eddy current fields induced from diffusion gradients for different gradients strengths (up to 300 mT/m), diffusion directions, and shots in a 3D multi-shot EPI sequence on a 3T Connectom scanner. The efficacy of dynamic field monitoring-based image reconstruction was demonstrated on high-resolution whole brain ex vivo dMRI. A 3D multi-shot image reconstruction framework was informed with the actual nonlinear phase evolution measured with the dynamic field camera, thereby accounting for high-order eddy currents fields on top of the image encoding gradients in the image formation model. Results Eddy current fields from diffusion gradients at high gradient strength in a 3T Connectom scanner are highly nonlinear in space and time, inducing high-order spatial phase modulations between odd/even echoes and shots that are not static during the readout. Superior reduction of ghosting and geometric distortion was achieved with dynamic field monitoring compared to ghosting approaches such as navigator- and structured low-rank-based methods or MUSE, followed by image-based distortion correction with eddy. Improved dMRI analysis is demonstrated with diffusion tensor imaging and high-angular resolution diffusion imaging. Conclusion Strong eddy current artifacts characteristic of high gradient strength dMRI can be well corrected with dynamic field monitoring-based image reconstruction, unlike the two-step approach consisting of ghosting correction followed by geometric distortion reduction with eddy.
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Ramos-Llordén G, Lobos RA, Kim TH, Tian Q, Witzel T, Lee HH, Scholz A, Keil B, Yendiki A, Bilgiç B, Haldar JP, Huang SY. High-fidelity, high-spatial-resolution diffusion magnetic resonance imaging of ex vivo whole human brain at ultra-high gradient strength with structured low-rank echo-planar imaging ghost correction. NMR Biomed 2023; 36:e4831. [PMID: 36106429 PMCID: PMC9883835 DOI: 10.1002/nbm.4831] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 08/20/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
Diffusion magnetic resonance imaging (dMRI) of whole ex vivo human brain specimens enables three-dimensional (3D) mapping of structural connectivity at the mesoscopic scale, providing detailed evaluation of fiber architecture and tissue microstructure at a spatial resolution that is difficult to access in vivo. To account for the short T2 and low diffusivity of fixed tissue, ex vivo dMRI is often acquired using strong diffusion-sensitizing gradients and multishot/segmented 3D echo-planar imaging (EPI) sequences to achieve high spatial resolution. However, the combination of strong diffusion-sensitizing gradients and multishot/segmented EPI readout can result in pronounced ghosting artifacts incurred by nonlinear spatiotemporal variations in the magnetic field produced by eddy currents. Such ghosting artifacts cannot be corrected with conventional correction solutions and pose a significant roadblock to leveraging human MRI scanners with ultrahigh gradients for ex vivo whole-brain dMRI. Here, we show that ghosting-correction approaches that correct for either polarity-related ghosting or shot-to-shot variations in a separate manner are suboptimal for 3D multishot diffusion-weighted EPI experiments in fixed human brain specimens using strong diffusion-sensitizing gradients on the 3-T Connectom MRI scanner, resulting in orientationally biased dMRI estimates. We apply a recently developed advanced k-space reconstruction method based on structured low-rank matrix (SLM) modeling that handles both polarity-related ghosting and shot-to-shot variation simultaneously, to mitigate artifacts in high-angular resolution multishot dMRI data acquired in several fixed human brain specimens at 0.7-0.8-mm isotropic spatial resolution using b-values up to 10,000 s/mm2 and gradient strengths up to 280 mT/m. We demonstrate the improved mapping of diffusion tensor imaging and fiber orientation distribution functions in key neuroanatomical areas distributed across the whole brain using SLM-based EPI ghost correction compared with alternative techniques.
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Affiliation(s)
- Gabriel Ramos-Llordén
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Rodrigo A. Lobos
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Tae Hyung Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Computer Engineering, Hongik University, Seoul, Republic of Korea
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Alina Scholz
- Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany
| | - Boris Keil
- Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Marburg, Philipps University of Marburg, Marburg, Germany
| | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Berkin Bilgiç
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Justin P. Haldar
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Susie Y. Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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15
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Wang CT, Xu JC, Chan KC, Lee HH, Tso CY, Lin CSK, Chao CYH, Fu SC. Infection control measures for public transportation derived from the flow dynamics of obstructed cough jet. J Aerosol Sci 2022; 163:105995. [PMID: 35382445 PMCID: PMC8971108 DOI: 10.1016/j.jaerosci.2022.105995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/21/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
During the COVID-19 pandemic, WHO and CDC suggest people stay 1 m and 1.8 m away from others, respectively. Keeping social distance can avoid close contact and mitigate infection spread. Many researchers suspect that suggested distances are not enough because aerosols can spread up to 7-8 m away. Despite the debate on social distance, these social distances rely on unobstructed respiratory activities such as coughing and sneezing. Differently, in this work, we focused on the most common but less studied aerosol spread from an obstructed cough. The flow dynamics of a cough jet blocked by the backrest and gasper jet in a cabin environment was characterized by the particle image velocimetry (PIV) technique. It was proved that the backrest and the gasper jet can prevent the front passenger from droplet spray in public transportation where maintaining social distance was difficult. A model was developed to describe the cough jet trajectory due to the gasper jet, which matched well with PIV results. It was found that buoyancy and inside droplets almost do not affect the short-range cough jet trajectory. Infection control measures were suggested for public transportation, including using backrest/gasper jet, installing localized exhaust, and surface cleaning of the backrest.
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Affiliation(s)
- C T Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - J C Xu
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - K C Chan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - H H Lee
- Department of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - C Y Tso
- Department of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Carol S K Lin
- Department of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Christopher Y H Chao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- Department of Building Environment and Energy Engineering & Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - S C Fu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
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16
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Fan Q, Eichner C, Afzali M, Mueller L, Tax CMW, Davids M, Mahmutovic M, Keil B, Bilgic B, Setsompop K, Lee HH, Tian Q, Maffei C, Ramos-Llordén G, Nummenmaa A, Witzel T, Yendiki A, Song YQ, Huang CC, Lin CP, Weiskopf N, Anwander A, Jones DK, Rosen BR, Wald LL, Huang SY. Mapping the Human Connectome using Diffusion MRI at 300 mT/m Gradient Strength: Methodological Advances and Scientific Impact. Neuroimage 2022; 254:118958. [PMID: 35217204 DOI: 10.1016/j.neuroimage.2022.118958] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 12/20/2022] Open
Abstract
Tremendous efforts have been made in the last decade to advance cutting-edge MRI technology in pursuit of mapping structural connectivity in the living human brain with unprecedented sensitivity and speed. The first Connectom 3T MRI scanner equipped with a 300 mT/m whole-body gradient system was installed at the Massachusetts General Hospital in 2011 and was specifically constructed as part of the Human Connectome Project. Since that time, numerous technological advances have been made to enable the broader use of the Connectom high gradient system for diffusion tractography and tissue microstructure studies and leverage its unique advantages and sensitivity to resolving macroscopic and microscopic structural information in neural tissue for clinical and neuroscientific studies. The goal of this review article is to summarize the technical developments that have emerged in the last decade to support and promote large-scale and scientific studies of the human brain using the Connectom scanner. We provide a brief historical perspective on the development of Connectom gradient technology and the efforts that led to the installation of three other Connectom 3T MRI scanners worldwide - one in the United Kingdom in Cardiff, Wales, another in Continental Europe in Leipzig, Germany, and the latest in Asia in Shanghai, China. We summarize the key developments in gradient hardware and image acquisition technology that have formed the backbone of Connectom-related research efforts, including the rich array of high-sensitivity receiver coils, pulse sequences, image artifact correction strategies and data preprocessing methods needed to optimize the quality of high-gradient strength dMRI data for subsequent analyses. Finally, we review the scientific impact of the Connectom MRI scanner, including advances in diffusion tractography, tissue microstructural imaging, ex vivo validation, and clinical investigations that have been enabled by Connectom technology. We conclude with brief insights into the unique value of strong gradients for dMRI and where the field is headed in the coming years.
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Affiliation(s)
- Qiuyun Fan
- Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Cornelius Eichner
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neuropsychology, Leipzig, Germany
| | - Maryam Afzali
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, Wales, UK; Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Lars Mueller
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Chantal M W Tax
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, Wales, UK; Image Sciences Institute, University Medical Center (UMC) Utrecht, Utrecht, Netherlands
| | - Mathias Davids
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA; Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Mirsad Mahmutovic
- Institute of Medical Physics and Radiation Protection (IMPS), TH-Mittelhessen University of Applied Sciences (THM), Giessen, Germany
| | - Boris Keil
- Institute of Medical Physics and Radiation Protection (IMPS), TH-Mittelhessen University of Applied Sciences (THM), Giessen, Germany
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Kawin Setsompop
- Department of Radiology, Stanford University, Stanford, CA, USA; Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Chiara Maffei
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Gabriel Ramos-Llordén
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Aapo Nummenmaa
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | | | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA
| | - Yi-Qiao Song
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA USA
| | - Chu-Chung Huang
- Key Laboratory of Brain Functional Genomics (MOE & STCSM), Affiliated Mental Health Center (ECNU), School of Psychology and Cognitive Science, East China Normal University, Shanghai, China; Shanghai Changning Mental Health Center, Shanghai, China
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.; Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Alfred Anwander
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neuropsychology, Leipzig, Germany
| | - Derek K Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, Wales, UK
| | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Lawrence L Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States.
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17
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Huang SY, Witzel T, Keil B, Scholz A, Davids M, Dietz P, Rummert E, Ramb R, Kirsch JE, Yendiki A, Fan Q, Tian Q, Ramos-Llordén G, Lee HH, Nummenmaa A, Bilgic B, Setsompop K, Wang F, Avram AV, Komlosh M, Benjamini D, Magdoom KN, Pathak S, Schneider W, Novikov DS, Fieremans E, Tounekti S, Mekkaoui C, Augustinack J, Berger D, Shapson-Coe A, Lichtman J, Basser PJ, Wald LL, Rosen BR. Connectome 2.0: Developing the next-generation ultra-high gradient strength human MRI scanner for bridging studies of the micro-, meso- and macro-connectome. Neuroimage 2021; 243:118530. [PMID: 34464739 PMCID: PMC8863543 DOI: 10.1016/j.neuroimage.2021.118530] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/10/2021] [Accepted: 08/27/2021] [Indexed: 11/26/2022] Open
Abstract
The first phase of the Human Connectome Project pioneered advances in MRI technology for mapping the macroscopic structural connections of the living human brain through the engineering of a whole-body human MRI scanner equipped with maximum gradient strength of 300 mT/m, the highest ever achieved for human imaging. While this instrument has made important contributions to the understanding of macroscale connectional topology, it has also demonstrated the potential of dedicated high-gradient performance scanners to provide unparalleled in vivo assessment of neural tissue microstructure. Building on the initial groundwork laid by the original Connectome scanner, we have now embarked on an international, multi-site effort to build the next-generation human 3T Connectome scanner (Connectome 2.0) optimized for the study of neural tissue microstructure and connectional anatomy across multiple length scales. In order to maximize the resolution of this in vivo microscope for studies of the living human brain, we will push the diffusion resolution limit to unprecedented levels by (1) nearly doubling the current maximum gradient strength from 300 mT/m to 500 mT/m and tripling the maximum slew rate from 200 T/m/s to 600 T/m/s through the design of a one-of-a-kind head gradient coil optimized to minimize peripheral nerve stimulation; (2) developing high-sensitivity multi-channel radiofrequency receive coils for in vivo and ex vivo human brain imaging; (3) incorporating dynamic field monitoring to minimize image distortions and artifacts; (4) developing new pulse sequences to integrate the strongest diffusion encoding and highest spatial resolution ever achieved in the living human brain; and (5) calibrating the measurements obtained from this next-generation instrument through systematic validation of diffusion microstructural metrics in high-fidelity phantoms and ex vivo brain tissue at progressively finer scales with accompanying diffusion simulations in histology-based micro-geometries. We envision creating the ultimate diffusion MRI instrument capable of capturing the complex multi-scale organization of the living human brain - from the microscopic scale needed to probe cellular geometry, heterogeneity and plasticity, to the mesoscopic scale for quantifying the distinctions in cortical structure and connectivity that define cyto- and myeloarchitectonic boundaries, to improvements in estimates of macroscopic connectivity.
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Affiliation(s)
- Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | | | - Boris Keil
- Institute of Medical Physics and Radiation Protection (IMPS), TH-Mittelhessen University of Applied Sciences (THM), Giessen, Germany
| | - Alina Scholz
- Institute of Medical Physics and Radiation Protection (IMPS), TH-Mittelhessen University of Applied Sciences (THM), Giessen, Germany
| | - Mathias Davids
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | | | - John E Kirsch
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Qiuyun Fan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Gabriel Ramos-Llordén
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Hong-Hsi Lee
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Aapo Nummenmaa
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Berkin Bilgic
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Kawin Setsompop
- Radiological Sciences Laboratory, Department of Radiology, Stanford University, Stanford, CA, USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexandru V Avram
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Michal Komlosh
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Dan Benjamini
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Kulam Najmudeen Magdoom
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Sudhir Pathak
- Learning Research and Development Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Walter Schneider
- Learning Research and Development Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Slimane Tounekti
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Choukri Mekkaoui
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jean Augustinack
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel Berger
- Department of Molecular and Cell Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Alexander Shapson-Coe
- Department of Molecular and Cell Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Jeff Lichtman
- Department of Molecular and Cell Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Peter J Basser
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Lawrence L Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Sui YV, Bertisch H, Lee HH, Storey P, Babb JS, Goff DC, Samsonov A, Lazar M. Quantitative Macromolecular Proton Fraction Mapping Reveals Altered Cortical Myelin Profile in Schizophrenia Spectrum Disorders. Cereb Cortex Commun 2021; 2:tgab015. [PMID: 34296161 PMCID: PMC8271044 DOI: 10.1093/texcom/tgab015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 01/12/2023] Open
Abstract
Myelin abnormalities have been reported in schizophrenia spectrum disorders (SSD) in white matter. However, in vivo examinations of cortical myeloarchitecture in SSD, especially those using quantitative measures, are limited. Here, we employed macromolecular proton fraction (MPF) obtained from quantitative magnetization transfer imaging to characterize intracortical myelin organization in 30 SSD patients versus 34 healthy control (HC) participants. We constructed cortical myelin profiles by extracting MPF values at various cortical depths and quantified their shape using a nonlinearity index (NLI). To delineate the association of illness duration with myelin changes, SSD patients were further divided into 3 duration groups. Between-group comparisons revealed reduced NLI in the SSD group with the longest illness duration (>5.5 years) compared with HC predominantly in bilateral prefrontal areas. Within the SSD group, cortical NLI decreased with disease duration and was positively associated with a measure of spatial working memory capacity as well as with cortical thickness (CT). Layer-specific analyses suggested that NLI decreases in the long-duration SSD group may arise in part from significantly increased MPF values in the midcortical layers. The current study reveals cortical myelin profile changes in SSD with illness progression, which may reflect an abnormal compensatory mechanism of the disorder.
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Affiliation(s)
- Yu Veronica Sui
- Department of Radiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Hilary Bertisch
- Department of Rehabilitation Medicine, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Hong-Hsi Lee
- Department of Radiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Pippa Storey
- Department of Radiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - James S Babb
- Department of Radiology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Donald C Goff
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Alexey Samsonov
- Department of Radiology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Mariana Lazar
- Department of Radiology, NYU Grossman School of Medicine, New York, NY 10016, USA
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19
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Lee HH, Novikov DS, Fieremans E. Removal of partial Fourier-induced Gibbs (RPG) ringing artifacts in MRI. Magn Reson Med 2021; 86:2733-2750. [PMID: 34227142 DOI: 10.1002/mrm.28830] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/29/2021] [Accepted: 04/16/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE To investigate and remove Gibbs-ringing artifacts caused by partial Fourier (PF) acquisition and zero filling interpolation in MRI data. THEORY AND METHODS Gibbs ringing of fully sampled data, leading to oscillations around tissue boundaries, is caused by the symmetric truncation of k-space. Such ringing can be removed by conventional methods, with the local subvoxel shifts method being the state-of-the-art. However, the asymmetric truncation of k-space in routinely used PF acquisitions leads to additional ringings of wider intervals in the PF sampling dimension that cannot be corrected solely based on magnitude images reconstructed via zero filling. Here, we develop a pipeline for the Removal of PF-induced Gibbs ringing (RPG) to remove ringing patterns of different periods by applying the conventional method twice. The proposed pipeline is validated on numerical phantoms, demonstrated on in vivo diffusion MRI measurements, and compared with the conventional method and neural network-based approach. RESULTS For PF = 7/8 and 6/8, Gibbs-ringings and subsequent bias in diffusion metrics induced by PF acquisition and zero filling are robustly removed by using the proposed RPG pipeline. For PF = 5/8, however, ringing removal via RPG leads to excessive image blurring due to the interplay of image phase and convolution kernel. CONCLUSIONS RPG corrects Gibbs-ringing artifacts in magnitude images of PF acquired data and reduces the bias in quantitative MR metrics. Considering the benefit of PF acquisition and the feasibility of ringing removal, we suggest applying PF = 6/8 when PF acquisition is necessary.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Dmitry S Novikov
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Els Fieremans
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
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20
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Lee HH, Fieremans E, Novikov DS. Realistic Microstructure Simulator (RMS): Monte Carlo simulations of diffusion in three-dimensional cell segmentations of microscopy images. J Neurosci Methods 2020; 350:109018. [PMID: 33279478 DOI: 10.1016/j.jneumeth.2020.109018] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/16/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Monte Carlo simulations of diffusion are commonly used as a model validation tool as they are especially suitable for generating the diffusion MRI signal in complicated tissue microgeometries. NEW METHOD Here we describe the details of implementing Monte Carlo simulations in three-dimensional (3d) voxelized segmentations of cells in microscopy images. Using the concept of the corner reflector, we largely reduce the computational load of simulating diffusion within and exchange between multiple cells. Precision is further achieved by GPU-based parallel computations. RESULTS Our simulation of diffusion in white matter axons segmented from a mouse brain demonstrates its value in validating biophysical models. Furthermore, we provide the theoretical background for implementing a discretized diffusion process, and consider the finite-step effects of the particle-membrane reflection and permeation events, needed for efficient simulation of interactions with irregular boundaries, spatially variable diffusion coefficient, and exchange. COMPARISON WITH EXISTING METHODS To our knowledge, this is the first Monte Carlo pipeline for MR signal simulations in a substrate composed of numerous realistic cells, accounting for their permeable and irregularly-shaped membranes. CONCLUSIONS The proposed RMS pipeline makes it possible to achieve fast and accurate simulations of diffusion in realistic tissue microgeometry, as well as the interplay with other MR contrasts. Presently, RMS focuses on simulations of diffusion, exchange, and T1 and T2 NMR relaxation in static tissues, with a possibility to straightforwardly account for susceptibility-induced T2* effects and flow.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA.
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
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21
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Lee HH, Papaioannou A, Novikov DS, Fieremans E. In vivo observation and biophysical interpretation of time-dependent diffusion in human cortical gray matter. Neuroimage 2020; 222:117054. [PMID: 32585341 PMCID: PMC7736473 DOI: 10.1016/j.neuroimage.2020.117054] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 12/25/2022] Open
Abstract
The dependence of the diffusion MRI signal on the diffusion time t is a hallmark of tissue microstructure at the scale of the diffusion length. Here we measure the time-dependence of the mean diffusivity D(t) and mean kurtosis K(t) in cortical gray matter and in 25 gray matter sub-regions, in 10 healthy subjects. Significant diffusivity and kurtosis time-dependence is observed for t=21.2-100 ms, and is characterized by a power-law tail ∼t-ϑ with dynamical exponent ϑ. To interpret our measurements, we systematize the relevant scenarios and mechanisms for diffusion time-dependence in the brain. Using the effective medium theory formalism, we derive an exact relation between the power-law tails in D(t) and K(t). The estimated dynamical exponent ϑ≃1/2 in both D(t) and K(t) is consistent with one-dimensional diffusion in the presence of randomly positioned restrictions along neurites. We analyze the short-range disordered statistics of synapses on axon collaterals in the cortex, and perform one-dimensional Monte Carlo simulations of diffusion restricted by permeable barriers with a similar randomness in their placement, to confirm the ϑ=1/2 exponent. In contrast, the Kärger model of exchange is less consistent with the data since it does not capture the diffusivity time-dependence, and the estimated exchange time from K(t) falls below our measured t-range. Although we cannot exclude exchange as a contributing factor, we argue that structural disorder along neurites is mainly responsible for the observed time-dependence of diffusivity and kurtosis. Our observation and theoretical interpretation of the t-1/2 tail in D(t) and K(t) altogether establish the sensitivity of a macroscopic MRI signal to micrometer-scale structural heterogeneities along neurites in human gray matter in vivo.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA.
| | - Antonios Papaioannou
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
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22
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Lee HH, Jespersen SN, Fieremans E, Novikov DS. The impact of realistic axonal shape on axon diameter estimation using diffusion MRI. Neuroimage 2020; 223:117228. [PMID: 32798676 PMCID: PMC7806404 DOI: 10.1016/j.neuroimage.2020.117228] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 07/29/2020] [Indexed: 11/24/2022] Open
Abstract
To study axonal microstructure with diffusion MRI, axons are typically modeled as straight impermeable cylinders, whereby the transverse diffusion MRI signal can be made sensitive to the cylinder’s inner diameter. However, the shape of a real axon varies along the axon direction, which couples the longitudinal and transverse diffusion of the overall axon direction. Here we develop a theory of the intra-axonal diffusion MRI signal based on coarse-graining of the axonal shape by 3-dimensional diffusion. We demonstrate how the estimate of the inner diameter is confounded by the diameter variations (beading), and by the local variations in direction (undulations) along the axon. We analytically relate diffusion MRI metrics, such as time-dependent radial diffusivity D⊥(t) and kurtosis K⊥(t), to the axonal shape, and validate our theory using Monte Carlo simulations in synthetic undulating axons with randomly positioned beads, and in realistic axons reconstructed from electron microscopy images of mouse brain white matter. We show that (i) In the narrow pulse limit, the inner diameter from D⊥(t) is overestimated by about twofold due to a combination of axon caliber variations and undulations (each contributing a comparable effect size); (ii) The narrow-pulse kurtosis K⊥∣t→∞ deviates from that in an ideal cylinder due to caliber variations; we also numerically calculate the fourth-order cumulant for an ideal cylinder in the wide pulse limit, which is relevant for inner diameter overestimation; (iii) In the wide pulse limit, the axon diameter overestimation is mainly due to undulations at low diffusion weightings b; and (iv) The effect of undulations can be considerably reduced by directional averaging of high-b signals, with the apparent inner diameter given by a combination of the axon caliber (dominated by the thickest axons), caliber variations, and the residual contribution of undulations.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA.
| | - Sune N Jespersen
- CFIN/MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA; Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, USA
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Abstract
To determine whether policies to limit transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hinder spread of other infectious diseases, we analyzed the National Health Insurance database in Taiwan. Rates of other infections were significantly lower after SARS-CoV-2 prevention measures were announced. This finding can be applied to cost-effectiveness of SARS-CoV-2 prevention.
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Lee HH, Papaioannou A, Kim SL, Novikov DS, Fieremans E. A time-dependent diffusion MRI signature of axon caliber variations and beading. Commun Biol 2020; 3:354. [PMID: 32636463 PMCID: PMC7341838 DOI: 10.1038/s42003-020-1050-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 06/04/2020] [Indexed: 01/08/2023] Open
Abstract
MRI provides a unique non-invasive window into the brain, yet is limited to millimeter resolution, orders of magnitude coarser than cell dimensions. Here, we show that diffusion MRI is sensitive to the micrometer-scale variations in axon caliber or pathological beading, by identifying a signature power-law diffusion time-dependence of the along-fiber diffusion coefficient. We observe this signature in human brain white matter and identify its origins by Monte Carlo simulations in realistic substrates from 3-dimensional electron microscopy of mouse corpus callosum. Simulations reveal that the time-dependence originates from axon caliber variation, rather than from mitochondria or axonal undulations. We report a decreased amplitude of time-dependence in multiple sclerosis lesions, illustrating the potential sensitivity of our method to axonal beading in a plethora of neurodegenerative disorders. This specificity to microstructure offers an exciting possibility of bridging across scales to image cellular-level pathology with a clinically feasible MRI technique.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Biomedical Imaging and Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA.
| | - Antonios Papaioannou
- Center for Biomedical Imaging and Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Sung-Lyoung Kim
- Center for Biomedical Imaging and Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Dmitry S Novikov
- Center for Biomedical Imaging and Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Els Fieremans
- Center for Biomedical Imaging and Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
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25
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Lee HH, Faundez L, Yarbrough C, Lewis CW, LoSasso AT. Patterns in Pediatric Dental Surgery under General Anesthesia across 7 State Medicaid Programs. JDR Clin Trans Res 2020; 5:358-365. [PMID: 32040927 DOI: 10.1177/2380084420906114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES Children's access to dental general anesthesia (DGA) is limited, with highly variable wait times. Access factors occur at the levels of facility, dental provider, and anesthesia provider. It is unknown if these factors also influence utilization of dental surgery. We characterized patterns in DGA utilization by system, provider, population, and individual disease levels to explain variation. METHODS We conducted a cross-sectional analysis of Medicaid-enrolled children (≤9 y) who received DGA in Massachusetts, Maryland, Texas, Connecticut, Washington, Illinois, and Florida from 2011 to 2012. DGA events were characterized by the place of service, measures of disease burden, average reimbursements for dental provider and anesthesia provider, and average total expenditures. RESULTS A total of 10,149,793 children met study eligibility criteria. States with similar patterns of caries-related visits, such as Illinois (16% of Medicaid enrollees had a caries-related claim) and Washington (22%), had different DGA rates (1% and 17%, respectively). Reimbursement rates for dental providers, DGA services, and nonhospital places of services did not consistently align in states with higher DGA rates. Surgical extraction rates, as a proxy for the most severe disease, exceeded 75% in Maryland, which had the lowest DGA rate (0.3%). CONCLUSIONS Variation in DGA rates across states was not explained by reimbursements rates (provider, DGA services, place of service) or population or individual level of caries burden. Efforts to evaluate and alter utilization of DGA should consider factors such as dental and anesthesia provider capacity, health facility capacity (hospital vs. ambulatory surgery center vs. office), and population- and individual-level disease burden. Our negative findings suggest the presence of other social determinants of oral health that influence utilization of services (e.g., race/ethnicity, language preference, immigration status, policy and budget goals), which should be explored. Our findings also raise the specter that variation in surgical rates may represent instances of unmet needs or overtreatment. KNOWLEDGE TRANSFER STATEMENT The results of this study can be used by clinicians and policy makers as they address policy and clinical interventions to influence children with severe caries. Interventions to change utilization of surgical services on a population level may need to include state-specific factors that extend beyond reimbursement, disease burden, anesthesia provider type, or facility type.
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Affiliation(s)
- H H Lee
- Department of Anesthesiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - L Faundez
- Department of Economics, University of Illinois at Chicago, Chicago, IL, USA
| | - C Yarbrough
- Illinois Health and Hospital Association, Chicago, IL, USA
| | - C W Lewis
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - A T LoSasso
- Department of Economics, DePaul University, Chicago, IL, USA
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26
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Lee HH, Kim KH, Kim HY. Development and control of a hybrid active mount module for precision stages. Rev Sci Instrum 2020; 91:026101. [PMID: 32113380 DOI: 10.1063/1.5122806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
In recent years, precision stages, which are widely used in many industrial fields, have been required to have a higher speed, larger size, and higher precision to help realize higher productivity and product quality. High-performance positioning techniques for inspection and production equipment are classified as one of the most challenging technologies. Vibration control is crucial to realize high-precision positioning technologies. In a precision system, various vibrations exist, which act as disturbances and can degrade the system performance. Minimizing the vibrations generated by the system can, thus, help improve the accuracy of system positioning. This paper proposes a hybrid active mount module for a precision stage. The developed module improves stage performance by reducing the base vibration arising from the floor, minimizing the vibration caused by the driving linear motors of the precision stage, and reducing the settling time by compensating the offset displacement due to the nonlinearity of the passive mount during stage driving. The prototype design is presented herein, and the experimental results demonstrate the potential of the developed device. The developed system is expected to effectively improve the stage performance by controlling the various causes of vibration.
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Affiliation(s)
- H H Lee
- School of Mechatronics Engineering, Korea Polytechnic University, Siheung-si 15073, South Korea
| | - K H Kim
- School of Mechatronics Engineering, Korea Polytechnic University, Siheung-si 15073, South Korea
| | - H Y Kim
- Manufacturing System R&D Group, Korea Institute of Industrial Technology, Cheonan-si 31056, South Korea
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27
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Singam V, Rastogi S, Patel KR, Lee HH, Silverberg JI. The mental health burden in acne vulgaris and rosacea: an analysis of the US National Inpatient Sample. Clin Exp Dermatol 2019; 44:766-772. [PMID: 30706514 DOI: 10.1111/ced.13919] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Little is known about the mental health (MH) hospitalization among patients with acne and rosacea. AIMS To determine the MH disorders and cost burden associated with acne and rosacea. METHODS Data were examined from the 2002-2012 US National Inpatient Sample, comprising a sample of ~20% of all US paediatric and adult hospitalizations (n = 87 053 155 admissions). RESULTS A diagnosis of ≥ 1 MH disorder was much more common among all inpatients with vs. those without a diagnosis of acne (43.7% vs. 20.0%, respectively) and rosacea (35.1% vs. 20.0%, respectively). In multivariable logistic regression models controlling for sex, age, race/ethnicity and insurance status, acne (adjusted OR = 13.02; 95% CI 11.75-14.42) and rosacea (adjusted OR = 1.70; 95% CI 1.56-1.95) were associated with significantly higher odds of a primary admission for an MH disorder (13 and 8, respectively, of 15 MH disorders examined). Both acne and rosacea were associated with higher risk of mood, anxiety, impulse control and personality disorders, and with > $2 million of excess mean annual costs of hospitalization for MH disorders in the USA. CONCLUSION In this study, inpatients with acne or rosacea had increased odds of comorbid MH disorders. In particular, there was an increased number of hospital admissions secondary to a primary MH disorder with coexistent acne/rosacea. MH comorbidities were associated with considerable excess costs among inpatients with acne or rosacea.
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Affiliation(s)
- V Singam
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - S Rastogi
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - K R Patel
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - H H Lee
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - J I Silverberg
- Departments of Dermatology, Preventative Medicine, and Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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28
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Lee HH, Kim DH, Lee KW, Kim KE, Shin DE, An BK. Dietary Effects of Natural Polyphenol Antioxidant on Laying Performance and Egg Quality of Laying Hens Fed Diets with Oxidized Oil. Braz J Poult Sci 2019. [DOI: 10.1590/1806-9061-2018-0791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- HH Lee
- Konkuk University, Republic of Korea; Daeho Co., Ltd, Republic of Korea
| | - DH Kim
- Konkuk University, Republic of Korea
| | - KW Lee
- Konkuk University, Republic of Korea
| | - KE Kim
- Nonghyup Feed, Republic of Korea
| | - DE Shin
- Nonghyup Feed, Republic of Korea
| | - BK An
- Konkuk University, Republic of Korea
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29
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Fieremans E, Lee HH. Physical and numerical phantoms for the validation of brain microstructural MRI: A cookbook. Neuroimage 2018; 182:39-61. [PMID: 29920376 PMCID: PMC6175674 DOI: 10.1016/j.neuroimage.2018.06.046] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 06/08/2018] [Accepted: 06/13/2018] [Indexed: 12/24/2022] Open
Abstract
Phantoms, both numerical (software) and physical (hardware), can serve as a gold standard for the validation of MRI methods probing the brain microstructure. This review aims to provide guidelines on how to build, implement, or choose the right phantom for a particular application, along with an overview of the current state-of-the-art of phantoms dedicated to study brain microstructure with MRI. For physical phantoms, we discuss the essential requirements and relevant characteristics of both the (NMR visible) liquid and (NMR invisible) phantom materials that induce relevant microstructural features detectable via MRI, based on diffusion, intra-voxel incoherent motion, magnetization transfer or magnetic susceptibility weighted contrast. In particular, for diffusion MRI, many useful phantoms have been proposed, ranging from simple liquids to advanced biomimetic phantoms consisting of hollow or plain microfibers and capillaries. For numerical phantoms, the focus is on Monte Carlo simulations of random walk, for which the basic principles, along with useful criteria to check and potential pitfalls are reviewed, in addition to a literature overview highlighting recent advances. While many phantoms exist already, the current review aims to stimulate further research in the field and to address remaining needs.
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Affiliation(s)
- Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA.
| | - Hong-Hsi Lee
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
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30
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Lee HH, Fieremans E, Novikov DS. What dominates the time dependence of diffusion transverse to axons: Intra- or extra-axonal water? Neuroimage 2018; 182:500-510. [PMID: 29253652 PMCID: PMC6004237 DOI: 10.1016/j.neuroimage.2017.12.038] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 11/18/2017] [Accepted: 12/13/2017] [Indexed: 12/31/2022] Open
Abstract
Brownian motion of water molecules provides an essential length scale, the diffusion length, commensurate with cell dimensions in biological tissues. Measuring the diffusion coefficient as a function of diffusion time makes in vivo diffusion MRI uniquely sensitive to the cellular features about three orders of magnitude below imaging resolution. However, there is a longstanding debate, regarding which contribution - intra- or extra-cellular - is more relevant in the overall time-dependence of the MRI-derived diffusion metrics. Here we resolve this debate in the human brain white matter. By varying not just the diffusion time, but also the gradient pulse duration of a standard diffusion MRI sequence, we identify a functional form of the measured time-dependent diffusion coefficient transverse to white matter tracts in 10 healthy volunteers. This specific functional form is shown to originate from the extra-axonal space, and provides estimates of the fiber packing correlation length for axons in a bundle. Our results offer a metric for the outer axonal diameter, a promising candidate marker for demyelination in neurodegenerative diseases. From the methodological perspective, our analysis demonstrates how competing models, which describe different physics yet interpolate standard measurements equally well, can be distinguished based on their prediction for an independent "orthogonal" measurement.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY 10016, United States.
| | - Els Fieremans
- Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY 10016, United States
| | - Dmitry S Novikov
- Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY 10016, United States
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Hwang IC, Kim AJ, Ro H, Jung JY, Chang JH, Lee HH, Chung W, Park YH. Changes in Bone Mineral Density After Kidney Transplantation. Transplant Proc 2018; 50:2506-2508. [PMID: 30316387 DOI: 10.1016/j.transproceed.2018.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/22/2018] [Accepted: 04/06/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Numerous studies have shown that osteoporosis is common in kidney transplant recipients. However, the change in bone mineral density after kidney transplantation (KT) is not fully understood. METHODS Thirty-nine kidney transplant recipients with bone densitometry at pretransplant and 24 months after KT were reviewed. RESULTS The recipients' median age (44.5 ± 10.7 years) and dialysis duration before KT (4.2 ± 3.4 years) were recorded. The T-scores of the lumbar spine and femur neck at 24 months after KT were positively associated with the respective pretransplant T-score (P < .001 in the lumbar spine and P < .001 in the femur neck). However, the T-score after KT did not show significant change (P = .680 in lumbar spine, P = .093 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were negatively associated with the respective pretransplant T-scores (P = .001 in lumbar spine, P = .026 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were also associated with the pretransplant T-scores after the adjustment of other variables. CONCLUSION The change of bone mineral density was related with pretransplant bone mineral density. Careful follow-up of bone densitometry for KT recipients was needed.
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Affiliation(s)
- I C Hwang
- Department of Medicine, Gachon University College of Medicine, Inchon, Republic of Korea
| | - A J Kim
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea
| | - H Ro
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea.
| | - J Y Jung
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea
| | - J H Chang
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea
| | - H H Lee
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea
| | - W Chung
- Department of Internal Medicine, Gachon University Gil Medical Center, Inchon, Republic of Korea
| | - Y H Park
- Department of Surgery, Gachon University Gil Medical Center, Inchon, Republic of Korea
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Yoon YE, Lee HH, Na JC, Huh KH, Kim MS, Kim SI, Kim YS, Han WK. Impact of Cigarette Smoking on Living Kidney Donors. Transplant Proc 2018; 50:1029-1033. [PMID: 29731061 DOI: 10.1016/j.transproceed.2018.02.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/17/2018] [Accepted: 02/22/2018] [Indexed: 01/23/2023]
Abstract
BACKGROUND Smoking is known to result in a decline in renal allograft function and survival of recipients; however, the effect of smoking on living kidney donors remains unknown. In this study we evaluated the impact of cigarette smoking on renal function of kidney donors. METHODS Among 1056 donors who underwent nephrectomy, 612 completed the 6-month follow-up protocol and were enrolled in the study. The association of smoking status, including pack-years smoking history, and postoperative renal function was evaluated. RESULTS Among donors, 68.1% had never smoked, 8% were former smokers, and 23.9% were current smokers. Donors who never smoked were older than former and current smokers (42.3 ± 11.8, 41.9 ± 11.1, and 38.3 ± 10.9 years, respectively; P < .001). There was no difference in preoperative renal function between groups; however, postoperative estimated glomerular filtration rate (eGFR) was lower in former and current smokers than in those who never smoked (64.6 ± 13.8, 64.7 ± 12.3, and 67.8 ± 13.1 mL/min/1.73 m2, respectively; P = .023). In former and current smokers, pack-years smoking history was negatively associated with pre- and postoperative eGFR (r = -0.305 and -0.435, P < .001), and correlated with postoperative percent eGFR decline (r = 0.248, P < .001). Smoking history was associated with postoperative development of chronic kidney disease (CKD). Especially in former smokers, a smoking history of more than 12 pack-years was strongly associated with development of CKD (odds ratio = 7.5, P = .003). CONCLUSION Even if they no longer smoke, donors with a smoking history require close observation due to increased risk of CKD development after kidney donation. A detailed pack-years smoking history should be obtained, and smoking cessation strategies should be implemented in kidney donors.
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Affiliation(s)
- Y E Yoon
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea
| | - H H Lee
- Department of Urology, National Health Insurance Service Ilsan Hospital, Goyang, Korea
| | - J C Na
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - K H Huh
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - M S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - S I Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - Y S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - W K Han
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
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Bae JM, Lee HH, Lee BI, Lee KM, Eun SH, Cho ML, Kim JS, Park JM, Cho YS, Lee IS, Kim SW, Choi H, Choi MG. Incidence of psoriasiform diseases secondary to tumour necrosis factor antagonists in patients with inflammatory bowel disease: a nationwide population-based cohort study. Aliment Pharmacol Ther 2018; 48:196-205. [PMID: 29869804 DOI: 10.1111/apt.14822] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/23/2018] [Accepted: 05/02/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND There are increasing reports of paradoxical psoriasiform diseases secondary to anti-tumour necrosis factor (TNF) agents. AIMS To determine the risks of paradoxical psoriasiform diseases secondary to anti-TNF agents in patients with inflammatory bowel disease (IBD). METHODS A nationwide population study was performed using the Korea National Health Insurance Claim Data. A total of 50 502 patients with IBD were identified between 2007 and 2016. We compared 5428 patients who were treated with any anti-TNF agent for more than 6 months (anti-TNF group) and 10 856 matched controls who had never taken anti-TNF agents (control group). RESULTS Incidence of psoriasis was significantly higher in the anti-TNF group (36.8 per 10 000 person-years) compared to the control group (14.5 per 10 000 person-years) (hazard ratio [HR] 2.357, 95% confidence interval [CI] 1.668-3.331). Palmoplantar pustulosis (HR 9.355, 95% CI 2.754-31.780) and psoriatic arthritis (HR 2.926, 95% CI 1.640-5.218) also showed higher risks in the anti-TNF group. In subgroup analyses, HRs for psoriasis by IBD subtype were 2.549 (95% CI 1.658-3.920) in Crohn's disease and 2.105 (95% CI 1.155-3.836) in ulcerative colitis. Interestingly, men and younger (10-39 years) patients have significantly higher risks of palmoplantar pustulosis (HR 19.682 [95% CI 3.867-100.169] and HR 14.318 [95% CI 2.915-70.315], respectively), whereas women and older (≥40 years) patients showed similar rates between the two groups. CONCLUSIONS The risks of psoriasiform diseases are increased by anti-TNF agents in patients with IBD. Among psoriasiform diseases, the risk of palmoplantar pustulosis shows the biggest increase particularly in male and younger patients.
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Affiliation(s)
- J M Bae
- Department of Dermatology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - H H Lee
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - B-I Lee
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - K-M Lee
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - S H Eun
- Department of Dermatology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - M-L Cho
- The Rheumatism Research Center, Catholic Research Institute of Medical Science, The Catholic University of Korea, Seoul, Korea
| | - J S Kim
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - J M Park
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - Y-S Cho
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - I S Lee
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
| | - S W Kim
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - H Choi
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - M-G Choi
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Catholic Photomedicine Research Institute, Seoul, Korea
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Na JC, Park JS, Yoon MG, Lee HH, Yoon YE, Huh KH, Kim YS, Han WK. Long-term Follow-up of Living Kidney Donors With Chronic Kidney Disease at 1 Year After Nephrectomy. Transplant Proc 2018; 50:1018-1021. [PMID: 29731059 DOI: 10.1016/j.transproceed.2018.02.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/12/2018] [Accepted: 02/22/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Although renal function recovery of living kidney donors has been reported in a number of studies, many patients show poor recovery, and the long-term prognosis of these patients has not been well studied. In this investigation we explored the long-term prognosis of renal function in patients with chronic kidney disease (CKD) at 1 year after nephrectomy. METHODS Patients who underwent donor nephrectomy during the period from March 2006 to April 2014, with a follow-up creatinine study at 1 year postoperatively and more than 3 years of follow-up, were included in the study. Creatinine and estimated glomerular filtration rate (eGFR, using the Modification of Diet in Renal Disease formula) before and after surgery were studied. Age, sex, history of hypertension or diabetes, body mass index, blood pressure, complete blood count, preoperative routine serum chemistry, and urine study results were reviewed. RESULTS Among 841 patients who had donor nephrectomy, 362 were included in the study. There were 111 patients (30.6%) with eGFR <60 mL/min/1.73 m2 at 1 year postsurgery, and the median follow-up period was 62.8 months (interquartile range [IQR] 42.0-86.3 months). The maximum eGFR after 3-year follow-up was studied, and 48 patients (43.2%) never recovered eGFR to >60 mL/min/1.73 m2. Age, history of hypertension, preoperative eGFR, and eGFR at 1 year were predictive factors at univariate analysis. Multivariate analysis of these factors was studied, and age (52.5 [IQR 47-55.7] vs 47 [IQR 7-53] years, odds ratio [OR] 1.1, 95% confidence interval [CI] 1.02-1.15, P = .007), history of hypertension (16.7% vs 1.6%, OR 10.0, 95% CI 1.09-92.49, P = .042), and eGFR at 1 year (53.9 [IQR 50.3-56.0] vs 57.0 [IQR 54.2-58.4] mL/min/1.73 m2, OR 0.8, 95% CI 0.72-0.92, P = .002) remained as significant risk factors. CONCLUSION Of all living donors, 15.7% had CKD after >3 years of follow-up. Close observation is warranted when donors have CKD after 1 year follow-up, as 43.2% fail to recover renal function. Patients who are older, have a history of hypertension, and have low eGFR at 1-year follow-up are especially at risk.
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Affiliation(s)
- J C Na
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea
| | - J S Park
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea
| | - M-G Yoon
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea
| | - H H Lee
- Department of Urology, National Health Insurance Service Ilsan Hospital, Goyang-si, Korea
| | - Y E Yoon
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea
| | - K H Huh
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - Y S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - W K Han
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.
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Na JC, Park JS, Yoon MG, Lee HH, Yoon YE, Huh KH, Kim YS, Han WK. Delayed Recovery of Renal Function After Donor Nephrectomy. Transplant Proc 2018; 50:1022-1024. [PMID: 29731060 DOI: 10.1016/j.transproceed.2018.01.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 01/22/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Many living kidney donors are still at risk of chronic kidney disease (CKD) 1 year after nephrectomy. Although some donors still experience poor renal function, many exhibit delayed recovery of renal function afterwards. We studied the factors related to delayed recovery of renal function in patients with CKD at 1 year after nephrectomy. METHODS Patients who underwent donor nephrectomy from March 2006 to April 2014 with a follow-up creatinine study at 1 month, 6 months, 1 year, and after 3 years of follow-up were included in the study. Age, sex, history of hypertension or diabetes, body mass index, blood pressure, complete blood cell count, preoperative routine serum chemistry, and urine study results were reviewed. RESULTS Among 275 donors, 83 (30.2%) who had an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 at 1 year of follow-up were included in the study, and the eGFR was observed during a median follow-up of 62.0 months (interquartile range [IQR], 48.9-83.1 months). Those who had improvements in eGFR of >5 mL/min/1.73 m2 were included in the recovery group (n = 48 [57.8%]), and those who did not were included in the nonrecovery group (n = 35 [42.2%]). The preoperative and 1-year follow-up eGFR did not differ significantly between the 2 groups, and the maximum eGFR after 3 years was higher in the recovery group (68.68 mL/min/1.73 m2 [IQR, 61.81-75.64 mL/min/1.73 m2] vs 55.63 mL/min/1.73 m2 [IQR, 51.73-58.29 mL/min/1.73 m2]; P < .001). The recovery group was more likely to have a history of hypertension (4.2% vs 20%; P = .032), a lower body mass index (24.11 kg/m2 [IQR, 22.04-25.20 kg/m2] vs 25.25 kg/m2 [IQR, 23.23-26.44 kg/m2]; P = .01), and a lower preoperative uric acid level (4.7 mg/dL [IQR, 3.8-5.4 mg/dL] vs 5.3 mg/dL [IQR, 4.4-6.2 mg/dL]; P = .031). After multivariate logistic regression analysis, history of hypertension (odds ratio, 0.131; P = .022) and uric acid level (odds ratio, 0.641; P = .036,) remained as significant factors. CONCLUSIONS Although 30.2% of donors had CKD at 1 year after nephrectomy, 57.8% reported improved renal function. Those with a history of hypertension and high preoperative uric acid levels were less likely to have improvements in renal function and required close follow-up.
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Affiliation(s)
- J C Na
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Republic of Korea
| | - J S Park
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Republic of Korea
| | - M-G Yoon
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Republic of Korea
| | - H H Lee
- Department of Urology, National Health Insurance Service Ilsan Hospital, Goyang-si, Republic of Korea
| | - Y E Yoon
- Department of Urology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - K H Huh
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Y S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - W K Han
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea.
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Lee HH, Sodickson DK, Lattanzi R. An analytic expression for the ultimate intrinsic SNR in a uniform sphere. Magn Reson Med 2018; 80:2256-2266. [PMID: 29682800 DOI: 10.1002/mrm.27207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 11/09/2022]
Abstract
PURPOSE The ultimate intrinsic signal-to-noise ratio (UISNR) is normally calculated using electrodynamic simulations with a complete basis of modes. Here, we provide an exact solution for the UISNR at the center of a dielectric sphere and assess how accurately this solution approximates UISNR away from the center. METHODS We performed a mode analysis to determine which modes contribute to central UISNR - ζ(r→0). We then derived an analytic expression to calculate ζ(r→0) and analyzed its dependence on main magnetic field strength, sample geometry, and electrical properties. We validated the proposed solution against an established method based on dyadic Green's function simulations. RESULTS Only one divergence-free mode contributes to ζ(r→0). The UISNR given by the exact solution matched the full simulation results for various parameter settings, whereas calculation speed was approximately 1000 times faster. We showed that the analytic expression can approximate the UISNR with <5% error at positions as much as 10-20% of the radius away from the center. CONCLUSION The proposed formula enables rapid and direct calculation of UISNR in the central region of a sphere. The resulting UISNR value may be used, for example, as an absolute reference to assess the performance of head coils with spherical phantoms.
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Affiliation(s)
- Hong-Hsi Lee
- Center for Advanced Imaging Innovation and Research (CAI2R) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
| | - Daniel K Sodickson
- Center for Advanced Imaging Innovation and Research (CAI2R) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
| | - Riccardo Lattanzi
- Center for Advanced Imaging Innovation and Research (CAI2R) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
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Kim AJ, Ro H, Chang JH, Jung JY, Chung WK, Park YH, Lee HH. Suspected Frequent Relapsing IgG4-related Lung Disease in Kidney Transplant Patient: A Case Report. Transplant Proc 2018; 50:2572-2574. [PMID: 30316401 DOI: 10.1016/j.transproceed.2018.02.197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/19/2018] [Indexed: 12/21/2022]
Abstract
Besides the initial description of IgG4-related pancreatic disease, other sites are now commonly involved. However, occurrence of IgG4-related disease is rare in organ transplanted patients. A 57-year-old man who received a kidney transplantation presented with recurrent dyspnea on exertion. A computed tomography scan of the chest revealed bilateral interlobular septal thickening and multiple tubular and branching small nodular lesions in the right upper lobe, and mass-like consolidation of the left middle lobe. Despite no elevation of serum IgG4 level, a percutaneous core needle biopsy on consolidative mass showed interstitial fibrosis and infiltration of IgG4-positive plasma cells to be more than > 20 per high power field. After treatment with glucocorticoids and rituximab, the consolidative mass of the left middle lobe disappeared.
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Affiliation(s)
- A J Kim
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - H Ro
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - J H Chang
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - J Y Jung
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - W K Chung
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - Y H Park
- Department of Surgery, College of Medicine, Gachon University, Incheon, Korea
| | - H H Lee
- Department of Internal Medicine, College of Medicine, Gachon University, Incheon, Korea.
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Yoon YE, Lee KS, Lee YJ, Lee HH, Han WK. Renoprotective Effects of Carbon Monoxide-Releasing Molecule 3 in Ischemia-Reperfusion Injury and Cisplatin-Induced Toxicity. Transplant Proc 2018; 49:1175-1182. [PMID: 28583551 DOI: 10.1016/j.transproceed.2017.03.067] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND We investigated the effects of a soluble carbon monoxide-releasing molecule (CORM) in cisplatin-induced cytotoxicity and ischemia-reperfusion injury (IRI) in vitro. METHODS The effects of CORM-3 (12.5-200 μM) were assessed in normal kidney epithelial cells (HK-2, LLC-PK1) and renal cancer cells (Caki-1, Caki-2) subjected to cisplatin (50-200 μM) or IRI. To induce IRI, cells were placed in an anaerobic chamber (37°C, 95% nitrogen, 5% carbon dioxide) for 48 hours. Cells were transferred to complete medium and incubated at 37°C, 5% carbon dioxide for 6 hours. Cell viability (CCK assays), tumor necrosis factor (TNF)-α messenger RNA (mRNA) levels (quantitative reverse-transcriptase polymerase chain reaction), and protein expression of cleaved-caspase 3 and oxidative stress markers (including Erk1/2, JNK, and P38; Western blot) were assessed. RESULTS Viability after IRI was approximately 40% of control. Protective effects of CORM-3 in the IRI model were dose-dependent. Cell viability was 40% recovered in 200-μM CORM-3-pretreated cells compared with control. The protective effects of CORM-3 in cells exposed to cisplatin for 24 hours were weaker than in the IRI model. TNF-α mRNA was induced by stimulated IRI or cisplatin exposure; CORM-3 pretreatment attenuated the rise in TNF-α mRNA. IRI or cisplatin-induced activated oxidative stress markers decreased in CORM-3-pretreated cells. CORM-3 reduced expression of the apoptotic marker cleaved-caspase 3. CONCLUSION Our data demonstrate the protective effects of CORM-3 in cisplatin cytotoxicity and IRI in both normal kidney cells and renal cancer cells in vitro. CORM-3 exerts these effects by ameliorating inflammatory and oxidative stress pathways.
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Affiliation(s)
- Y E Yoon
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - K S Lee
- Department of Urology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Y J Lee
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - H H Lee
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - W K Han
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
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Lee HH, Kang SK, Yoon YE, Huh KH, Kim MS, Kim SI, Kim YS, Han WK. Impact of the Ratio of Visceral to Subcutaneous Adipose Tissue in Donor Nephrectomy Patients. Transplant Proc 2017; 49:940-943. [PMID: 28583563 DOI: 10.1016/j.transproceed.2017.03.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE It was reported that a metabolic syndrome affected the remaining renal function after living donor nephrectomy. However, the measurement of waist circumference is unclear because it cannot distinguish between visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). We investigate the clinical correlation between body adipose tissue and renal function recovery after living donor nephrectomy. METHODS From July 2013 to February 2015, 75 living kidney donors were enrolled. The VAT and SAT were measured by preoperative computed tomography (CT) scan. Body mass index (BMI), VAT, SAT, and VAT-to-SAT ratio were analyzed according to a postoperative renal function recovery. Receiver operating characteristic (ROC) was performed to predict estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 at postoperative 6 months for BMI, VAT, SAT, and VAT-to-SAT ratio. RESULTS The lowest value of eGFR (57.52 ± 11.20 mL/min/1.73 m2) was measured at postoperative day 7. There was no statistically significant difference in eGFR between 1 month and 3 months. BMI, VAT, SAT, and VAT-to-SAT ratio showed a statistically significant correlation with each other (Pearson correlation, P < .05). Also, the recovery time of eGFR was correlated with VAT-to-SAT ratio; it was significant at postoperative 1, 3, and 6 months. VAT-to-SAT ratio (0.654, 95% confidence interval 0.525-0.783, P = .024) had higher predictive value in ROC. CONCLUSION We developed a new variable to predict the value of lower eGFR (less than 60 mL/min/1.73 m2) at a postoperative 6 months in living kidney donor. According to a CT scan, VAT-to-SAT ratio can predict renal function recovery.
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Affiliation(s)
- H H Lee
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea; Department of Urology, National Health Insurance Service Ilsan Hospital, Goyang-si, Korea
| | - S K Kang
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea
| | - Y E Yoon
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea
| | - K H Huh
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - M S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - S I Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - Y S Kim
- Department of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - W K Han
- Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.
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Yoon YE, Cho YI, Kim SY, Lee HH, Huh KH, Kim YS, Han WK. Plasma Neutrophil Gelatinase-associated Lipoprotein in Living Kidney Donors. Transplant Proc 2017; 48:738-41. [PMID: 27234725 DOI: 10.1016/j.transproceed.2015.12.094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 12/30/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for acute kidney injury. This study was conducted to determine the clinical implications of perioperative plasma NGAL levels for renal function after living donor nephrectomy. METHODS Between July 2013 and May 2014, 112 donors underwent live donor nephrectomy at our institution. Donor plasma NGAL levels were measured perioperatively for 6 months. The relationship between perioperative plasma NGAL and recovery of renal function was analyzed. Renal function was estimated with the Modification of Diet in Renal Disease formula. RESULTS Mean preoperative NGAL was 62.1 ± 29.5 ng/mL. Plasma NGAL was most elevated 1 week postoperatively (218 ± 95.5 ng/mL), and stabilized after 1 month (122.9 ± 45.3 ng/mL). Preoperative plasma NGAL was not correlated with donor age or preoperative estimated glomerular filtration rates (eGFR), but was negatively correlated with 6-month eGFR (r = -0.458, P < .001). During the observation period, plasma NGAL at 1 week was most correlated with 6-month eGFR (r = -0.554, P < .001). An ROC curve analysis showed that age, preoperative eGFR, and 1-week postoperative plasma NGAL were highly predictive of developing of chronic kidney disease (CKD), defined as eGFR <60 mL/min/1.73 m(2), 6 months postoperatively (AUC = 0.91, P < .001). One-week postoperative plasma NGAL was also independently associated with CKD risk at 6 months (odds ratio: 1.13 for each 10 ng/mL increase, P = .013). CONCLUSION Plasma NGAL becomes elevated after kidney donation and can provide information about acute kidney injury during the compensatory hyperfiltration period. Donors with increased perioperative plasma NGAL require close observation because their possibility of developing CKD after donation may be greater.
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Affiliation(s)
- Y E Yoon
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Y I Cho
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
| | - S Y Kim
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - H H Lee
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - K H Huh
- Department of Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - Y S Kim
- Department of Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea
| | - W K Han
- Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
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Kim MJ, Kim TH, Park Y, Lee HH, Kim JM, Lim H, Hwang SY. A study of the dietary intakes by the pre-pregnancy body mass index in pregnant women. CLIN EXP OBSTET GYN 2017; 44:27-29. [PMID: 29714861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The authors analyzed the difference in weight gain and nutrition, according to the BMI before pregnancy. They divided 91 subjects into BMI group I (normal weight) and BMI group 2 (overweight) before pregnancy. In general, the BMI before pregnancy did not influence weight gain but, in the BMI group 2, the intakes of all of cholesterol, total fatty acids, vitamin B 12, iron, and copper were significantly higher. Neither group exhibited sufficient intake of vitamin B 1, vitamin B2, niacin, vitamin B6, folic acid, calcium, magnesium, iron, or zinc. Pre-pregnancy weight management and nutrition during pregnancy is very important.
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Kim TH, Lee HH, Kim JM. Efficacy of computed tomography for the diagnosis of postpartum hemorrhage. CLIN EXP OBSTET GYN 2017; 44:244-246. [PMID: 29746031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The authors evaluated the diagnosis of the cause of post-partum haemorrhage (PPH) by computed tomography (CT). They retrospectively transferred 15 patients with PPH from local clinics between January 2010 and December 2011. CT revealed diverse causes. Only two cases had no additional finding on CT. They found deep tearing extending to the lower uterine segment and uterine artery in two cases, whereas five cases were an arteriovenous malformation, and one case was a uterine pseudoaneurysm.
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Lee HH, Thomas LR, Piner KR, Maunder MN. Effects of age-based movement on the estimation of growth assuming random-at-age or random-at-length data. J Fish Biol 2017; 90:222-235. [PMID: 27774591 DOI: 10.1111/jfb.13177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
Simulation methods were used to generate paired data from a simulated population that included the age-based process of movement and the length-based process of gear selection. The age-based process caused bias in the estimates of growth parameters assuming random at length, even when relatively few age classes were affected. Methods that assumed random at age were biased by the subsequent inclusion of the length-based process of gear selection. Additional knowledge of the age structure of the sampled area is needed to ensure an unbiased estimate of the growth parameters when using the length-conditional approach in the presence of age-based movement. Estimates of the variability in the length-at-age relationship were better estimated with the length-conditional than the traditional method even when the assumptions of random at length were violated. Inclusion of paired observations of length and associated age inside the population dynamics model may be the most appropriate way of estimating growth.
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Affiliation(s)
- H H Lee
- NOAA Fisheries, Southwest Fisheries Science Center, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, U.S.A
| | - L R Thomas
- University of California Santa Barbara, Bren School of Environmental Science & Management, 2400 Bren Hall, University of California, Santa Barbara, CA, 93106, U.S.A
| | - K R Piner
- NOAA Fisheries, Southwest Fisheries Science Center, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, U.S.A
| | - M N Maunder
- Inter-American Tropical, Tuna Commission, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, U.S.A
- Center for the Advancement of Population Assessment Methodology, Scripps Institute of Oceanography, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, U.S.A
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Kang CS, Lee HH, Oh S, Lee SG, Wi HM, Kim YS, Kim HS. Study on the heat flux reconstruction with the infrared thermography for the divertor target plates in the KSTAR tokamak. Rev Sci Instrum 2016; 87:083508. [PMID: 27587124 DOI: 10.1063/1.4961030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An infrared (IR) thermography is the preferred diagnostic that can quantify heat flux by measuring the surface temperature distributions of the divertor plates. The IR thermography is successfully instrumented on Korea Superconducting Tokamak Advanced Research (KSTAR). In this study, finite volume method is considered to solve the heat conduction equations. 1D-, 2D-, and 3D models are developed and compared with various calculation algorithms, such as Duhamel's theorem and THEODOR. These comparisons show good agreement. In order to acquire more efficient and reliable calculation results, we consider two numerical analysis schemes, influence of temperature on thermal properties and image stabilization. Recently, this reconstruction code is successfully applied to the KSTAR IR thermography.
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Affiliation(s)
- C S Kang
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - H H Lee
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - S Oh
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - S G Lee
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - H M Wi
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - Y S Kim
- National Fusion Research Institute, Daejeon 305-806, South Korea
| | - H S Kim
- National Fusion Research Institute, Daejeon 305-806, South Korea
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Abstract
Racial disparities in how pain is treated in the emergency department (ED) for toothache have not been reported. Due to increasing reliance on EDs for dental care, the authors investigated whether race/ethnicity and insurance type are associated with treatment for toothache pain. The authors conducted a nationally representative cross-sectional study of ED toothache visits by adults (19 to 64 y old), using the 2008-2010 National Hospital Ambulatory Medical Care Survey. Multinomial regression models accounted for the complex survey design. Outcomes were pain medicines received: none, nonopioid only, or opioids. After adjusting for sociodemographic factors, black patients had 1.99 greater odds (P < 0.005) than white patients of receiving only a nonopioid pain medicine for toothache. Visits made by patients on Medicare, Medicaid, uninsured, or "other" insurance status had greater odds than the privately insured of receiving only a nonopioid pain medicine rather than an opioid (odds ratios, respectively: 4.8, P < 0.001; 2.1, P ≤ 0.001; 2.3, P < 0.01; and 4.1, P < 0.001). Blacks are less likely than whites to receive opioids in the ED for a toothache, even with similar levels of pain. Nonprivately insured patients have lower odds than the privately insured to receive opioids for toothache pain. A better understanding of the etiology of these disparities could lead to directed interventions. Knowledge Transfer Statement: This study presents findings novel to the body of pain and oral health care literature. Because there is an increasing reliance on the emergency department to address dental pain, disparities in how toothache pain is treated will be of great interest to a growing number of Americans, clinicians, and policy makers.
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Affiliation(s)
- H H Lee
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
| | - C W Lewis
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - C M McKinney
- Department of Oral Health Sciences, University of Washington, Seattle, WA, USA
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Fieremans E, Burcaw LM, Lee HH, Lemberskiy G, Veraart J, Novikov DS. In vivo observation and biophysical interpretation of time-dependent diffusion in human white matter. Neuroimage 2016; 129:414-427. [PMID: 26804782 DOI: 10.1016/j.neuroimage.2016.01.018] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 12/11/2015] [Accepted: 01/08/2016] [Indexed: 12/20/2022] Open
Abstract
The presence of micrometer-level restrictions leads to a decrease of diffusion coefficient with diffusion time. Here we investigate this effect in human white matter in vivo. We focus on a broad range of diffusion times, up to 600 ms, covering diffusion length scales up to about 30 μm. We perform stimulated echo diffusion tensor imaging on 5 healthy volunteers and observe a relatively weak time-dependence in diffusion transverse to major fiber tracts. Remarkably, we also find notable time-dependence in the longitudinal direction. Comparing models of diffusion in ordered, confined and disordered media, we argue that the time-dependence in both directions can arise due to structural disorder, such as axonal beads in the longitudinal direction, and the random packing geometry of fibers within a bundle in the transverse direction. These time-dependent effects extend beyond a simple picture of Gaussian compartments, and may lead to novel markers that are specific to neuronal fiber geometry at the micrometer scale.
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Affiliation(s)
- Els Fieremans
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA.
| | - Lauren M Burcaw
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Hong-Hsi Lee
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Gregory Lemberskiy
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Jelle Veraart
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA; iMinds Vision Lab, Department of Physics, University of Antwerp, Antwerp, Belgium
| | - Dmitry S Novikov
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
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Krauer F, Oakley-Mudge S, Brook MG, White JA, Low N, Lee HH. P08.22 How high is high risk? sexual behaviour and chlamydia infections in women attending genitourinary medicine clinics. Br J Vener Dis 2015. [DOI: 10.1136/sextrans-2015-052270.368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Lee HH, Loh SP, Bong CFJ, Sarbini SR, Yiu PH. Impact of phytic acid on nutrient bioaccessibility and antioxidant properties of dehusked rice. J Food Sci Technol 2015; 52:7806-16. [PMID: 26604353 DOI: 10.1007/s13197-015-1918-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 05/25/2015] [Accepted: 06/09/2015] [Indexed: 11/26/2022]
Abstract
Whole grains consumption promotes health benefits, but demonstrates controversial impacts from phytic acid in meeting requirements of good health. Therefore, this study was aimed to determine the nutrient bioaccessibility and antioxidant properties of rice cultivars named "Adan" or "Bario" and deduce the nutritional impact of phytic acid. Majority of the dehusked rice in the collection showed an acceptable level of in-vitro starch digestibility and in-vitro protein digestibility, but were poor in antioxidant properties and bioaccessibility of minerals (Ca, Fe and Zn). The drawbacks identified in the rice cultivars were due to relatively high phytic acid content (2420.6 ± 94.6 mg/100 g) and low phenolic content (152.39 ± 18.84 μg GAE/g). The relationship between phytic acid content and mineral bioaccessibility was strongest in calcium (r = 0.60), followed by iron (r = 0.40) and zinc (r = 0.27). Phytic acid content did not significantly correlate with in-vitro starch digestibility and in-vitro protein digestibility but showed a weak relationship with antioxidant properties. These suggest that phytic acid could significantly impair the mineral bioaccessibility of dehusked rice, and also act as an important antioxidant in non-pigmented rice. Bario rice cultivars offered dehusked rice with wide range of in-vitro digestibility of starch and protein, and also pigmented rice as a good source of antioxidants. However, there is a need to reduce phytic acid content in dehusked rice for improved mineral bioaccessibility among Bario rice cultivars.
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Affiliation(s)
- H H Lee
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, P.O. Box 396, Nyabau Road, 97008 Bintulu, Sarawak Malaysia
| | - S P Loh
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ; Laboratory of Molecular Biomedicine, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - C F J Bong
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, P.O. Box 396, Nyabau Road, 97008 Bintulu, Sarawak Malaysia
| | - S R Sarbini
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, P.O. Box 396, Nyabau Road, 97008 Bintulu, Sarawak Malaysia
| | - P H Yiu
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, P.O. Box 396, Nyabau Road, 97008 Bintulu, Sarawak Malaysia ; Centre of Excellence in Borneo Ecosystem Science Research, Universiti Putra Malaysia Bintulu Sarawak Campus, P.O. Box 396, Nyabau Road, 97008 Bintulu, Sarawak Malaysia
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Park J, Kim TH, Lee HH. Efficacy of fetal thigh volumetry in predicting birth weight using the virtual organ computer-aided analysis (VOCAL) technique. CLIN EXP OBSTET GYN 2015; 42:757-762. [PMID: 26753480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVES The present study was conducted to compare the accuracy of formulas used to calculate fetal thigh volume (FTV) using the virtual organ computer-aided analysis (VOCAL) technique with two-dimensional (2D) in formulas predicting birth weight. MATERIALS AND METHODS This was a prospective, cross-sectional study of 84 pregnant women with 72 hours of delivery evaluated at a university hospital between May, 2008 and April, 2010. After 2D ultrasounds (US) measurement, 3DUS was also used to determine FTV with estimates computed using the VOCAL program. RESULTS The correlation between fetal weight predicted by the 3D equation of FTV and the actual birth weight was significant. While FTV and the Hadlock II equation exhibited a low sensitivity for detection of low-birth-weight infants, FTV was a more sensitive method of detecting high-birth-weight infants than the Hadlock II equation. CONCLUSIONS It is clear that using 3DUS-VOCAL to measure FTV provides more accurate estimation of fetal birth weight.
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Ko WH, Lee HH, Jeon YM, Ida K, Lee JH, Yoon SW, Lee KD, Bae YS, Oh YK, Kwak JG. Rotation characteristics during the resonant magnetic perturbation induced edge localized mode suppression on the KSTAR. Rev Sci Instrum 2014; 85:11E413. [PMID: 25430320 DOI: 10.1063/1.4890402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Measuring rotation profiles with a reliable spatial resolution is one of the critical diagnostics in understanding the plasma behavior especially for the edge transport. In the KSTAR experiments, it has been consistently observed from the charge exchange spectroscopy measurements that the magnetic perturbations not only suppresses edge localized modes (ELMs) but also reduces toroidal rotations. In this paper, toroidal velocities of the carbon impurity and their profile evolutions during ELMy and ELM-suppressed phases are presented. The rotation profiles are shown to collapse immediately after an ELM burst and continue to build up until the next burst that accompanies another collapse. Toroidal rotations following the resonant magnetic perturbations applications are observed to be reduced along with the ELMs suppressed.
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Affiliation(s)
- Won-Ha Ko
- National Fusion Research Institute, Daejeon, South Korea
| | - H H Lee
- National Fusion Research Institute, Daejeon, South Korea
| | - Y M Jeon
- National Fusion Research Institute, Daejeon, South Korea
| | - K Ida
- National Institute for Fusion Science, Nagoya, Japan
| | - J H Lee
- National Fusion Research Institute, Daejeon, South Korea
| | - S W Yoon
- National Fusion Research Institute, Daejeon, South Korea
| | - K D Lee
- National Fusion Research Institute, Daejeon, South Korea
| | - Y S Bae
- National Fusion Research Institute, Daejeon, South Korea
| | - Y K Oh
- National Fusion Research Institute, Daejeon, South Korea
| | - J G Kwak
- National Fusion Research Institute, Daejeon, South Korea
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