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Oshiro H, Hata J, Nakashima D, Hayashi N, Haga Y, Hagiya K, Yoshimaru D, Okano H. Influence of Diffusion Time and Temperature on Restricted Diffusion Signal: A Phantom Study. Magn Reson Med Sci 2024; 23:136-145. [PMID: 36754420 PMCID: PMC11024708 DOI: 10.2463/mrms.mp.2022-0103] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 12/17/2022] [Indexed: 02/10/2023] Open
Abstract
PURPOSE Diffusion MRI is a physical measurement method that quantitatively indicates the displacement of water molecules diffusing in voxels. However, there are insufficient data to characterize the diffusion process physically in a uniform structure such as a phantom. This study investigated the transitional relationship between structure scale, temperature, and diffusion time for simple restricted diffusion using a capillary phantom. METHODS We performed diffusion-weighted pulsed-gradient stimulated-echo acquisition mode (STEAM) MRI with a 9.4 Tesla MRI system (Bruker BioSpin, Ettlingen, Germany) and a quadrature coil with an inner diameter of 86 mm (Bruker BioSpin). We measured the diffusion coefficients (radial diffusivity [RD]) of capillary plates (pore sizes 6, 12, 25, 50, and 100 μm) with uniformly restricted structures at various temperatures (10ºC, 20ºC, 30ºC, and 40ºC) and multiple diffusion times (12-800 ms). We evaluated the characteristics of scale, temperature, and diffusion time for restricted diffusion. RESULTS The RD decayed and became constant depending on the structural scale. Diffusion coefficient fluctuations with temperature occurred mostly under conditions of a large structural scale and short diffusion time. We obtained data suggesting that temperature-dependent changes in the diffusion coefficients follow physical laws. CONCLUSION No water molecules were observed outside the glass tubes in the capillary plates, and the capillary plates only reflected a restricted diffusion process within the structure.We experimentally evaluated the characteristics of simple restricted diffusion to reveal the transitional relationship of the diffusion coefficient with diffusion time, structure scale, and temperature through composite measurement.
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Affiliation(s)
- Hinako Oshiro
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
| | - Junichi Hata
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
- School of Medicine, Keio University, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | | | - Naoya Hayashi
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
| | - Yawara Haga
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
| | - Kei Hagiya
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
| | - Daisuke Yoshimaru
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
- School of Medicine, Keio University, Tokyo, Japan
- Division of Regenerative Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Hideyuki Okano
- Center for Brain Science, RIKEN, Wako, Saitama, Japan
- School of Medicine, Keio University, Tokyo, Japan
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2
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Henning P, Köster T, Haack F, Burrage K, Uhrmacher AM. Implications of different membrane compartmentalization models in particle-based in silico studies. R Soc Open Sci 2023; 10:221177. [PMID: 37416823 PMCID: PMC10320350 DOI: 10.1098/rsos.221177] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 06/12/2023] [Indexed: 07/08/2023]
Abstract
Studying membrane dynamics is important to understand the cellular response to environmental stimuli. A decisive spatial characteristic of the plasma membrane is its compartmental structure created by the actin-based membrane-skeleton (fences) and anchored transmembrane proteins (pickets). Particle-based reaction-diffusion simulation of the membrane offers a suitable temporal and spatial resolution to analyse its spatially heterogeneous and stochastic dynamics. Fences have been modelled via hop probabilities, potentials or explicit picket fences. Our study analyses the different approaches' constraints and their impact on simulation results and performance. Each of the methods comes with its own constraints; the picket fences require small timesteps, potential fences might induce a bias in diffusion in crowded systems, and probabilistic fences, in addition to carefully scaling the probability with the timesteps, induce higher computational costs for each propagation step.
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Affiliation(s)
- Philipp Henning
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany
| | - Till Köster
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany
| | - Fiete Haack
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany
| | - Kevin Burrage
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
- Visiting Professor, Department of Computer Science, University of Oxford, Oxford, UK
| | - Adelinde M. Uhrmacher
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany
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3
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K K H, Ajmera P, Agarwal A, Dahiya A, Parripati VK. Maple Syrup Urine Disease: An Uncommon Cause of Neonatal Febrile Seizures. Cureus 2023; 15:e40826. [PMID: 37489218 PMCID: PMC10363028 DOI: 10.7759/cureus.40826] [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] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2023] [Indexed: 07/26/2023] Open
Abstract
Maple syrup urine disease (MSUD) is a rare autosomal-recessive disorder. An enzyme complex called branched-chain alpha-keto acid dehydrogenase (BCKAD) metabolizes branched-chain amino acids (BCAAs), such as leucine, isoleucine, and valine, in the body. The deficiency of this enzyme causes the accumulation of BCAAs in cerebrospinal fluid, plasma, and urine. This metabolic illness is defined by abnormal levels of BCAAs. The pathognomonic illness marker alloisoleucine is produced in the absence of the BCKAD enzyme, which is part of a metabolic pathway involving three BCAAs and gets accumulated in the body. Classically, affected neonates present with feeding problems, vomiting, lethargy, and irritability, leading to seizures, coma, and death if left untreated. Blood and urine analysis reveals an accumulation of BCAAs in the plasma and urine. Here, we report the case of a neonate on day 10 of life with febrile seizures and non-acceptance of feeds, who was diagnosed with the classical form of MSUD. This is a classic case of MSUD which was evaluated exhaustively and revealed all classic features clinically and on investigations.
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Affiliation(s)
- Harshyenee K K
- Radiology, Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, IND
| | - Pranav Ajmera
- Radiology, Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, IND
| | - Aastha Agarwal
- Radiology, Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, IND
| | - Ajay Dahiya
- Radiology, Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, IND
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4
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Chakwizira A, Zhu A, Foo T, Westin CF, Szczepankiewicz F, Nilsson M. Diffusion MRI with free gradient waveforms on a high-performance gradient system: Probing restriction and exchange in the human brain. ArXiv 2023:arXiv:2304.02764v1. [PMID: 37064535 PMCID: PMC10104199] [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] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
The dependence of the diffusion MRI signal on the diffusion time carries signatures of restricted diffusion and exchange. Here we seek to highlight these signatures in the human brain by performing experiments using free gradient waveforms that are selectively sensitive to the two effects. We examine six healthy volunteers using both strong and ultra-strong gradients (80, 200 and 300 mT/m). In an experiment featuring a large set of gradient waveforms with different sensitivities to restricted diffusion and exchange (150 samples), our results reveal unique time-dependence signatures in grey and white matter, where the former is characterised by both restricted diffusion and exchange and the latter predominantly exhibits restricted diffusion. Furthermore, we show that gradient waveforms with independently varying sensitivities to restricted diffusion and exchange can be used to map exchange in the human brain. We consistently find that exchange in grey matter is at least twice as fast as in white matter, across all subjects and all gradient strengths. The shortest exchange times observed in this study were in the cerebellar cortex (115 ms). We also assess the feasibility of future clinical applications of the method used in this work, where we find that the grey-white matter exchange contrast obtained with a 25-minute 300 mT/m protocol is preserved by a 4-minute 300 mT/m and a 10-minute 80 mT/m protocol. Our work underlines the utility of free waveforms for detecting time-dependence signatures due to restricted diffusion and exchange in vivo, which may potentially serve as a tool for studying diseased tissue.
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Affiliation(s)
- Arthur Chakwizira
- Medical Radiation Physics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Ante Zhu
- GE Research, Niskayuna, New York, USA
| | | | - Carl-Fredrik Westin
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | | | - Markus Nilsson
- Department of Clinical Sciences Lund, Radiology, Lund University, Lund, Sweden
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5
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Puac-Polanco P, Zakhari N, Miller J, McComiskey D, Thornhill RE, Jansen GH, Nair VJ, Nguyen TB. Diagnostic Accuracy of Centrally Restricted Diffusion Sign in Cerebral Metastatic Disease: Differentiating Radiation Necrosis from Tumor Recurrence. Can Assoc Radiol J 2023; 74:100-109. [PMID: 35848632 DOI: 10.1177/08465371221115341] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Purpose: The centrally restricted diffusion sign of diffusion-weighted imaging (DWI) is associated with radiation necrosis (RN) in treated gliomas. Our goal was to evaluate its diagnostic accuracy to distinguish RN from tumor recurrence (TR) in treated brain metastases. Methods: Retrospective study of consecutive patients with brain metastases who developed a newly centrally necrotic lesion after radiotherapy (RT). One reader placed regions of interest (ROI) in the enhancing solid lesion and the non-enhancing central necrosis on the apparent diffusion coefficient (ADC) map. Two readers qualitatively assessed the presence of the centrally restricted diffusion sign. The final diagnosis was made by histopathology (n = 39) or imaging follow-up (n = 2). Differences between groups were assessed by Fisher's exact or Mann-Whitney U tests. Diagnostic accuracy and inter-reader agreement were evaluated using receiver operating characteristic (ROC) curve analysis and kappa scores. Results: Forty-one lesions (32 predominant RN; 9 predominant TR) were analyzed. An ADC value ≤ 1220 × 10-6 mm2/s (sensitivity 74%, specificity 89%, area under the curve [AUC] .85 [95% confidence interval {CI}, .70-.94] P < .0001) from the necrosis and an ADC necrosis/enhancement ratio ≤1.37 (sensitivity 74%, specificity 89%, AUC .82 [95% CI, .67-.93] P < .0001) provided the highest performance for RN diagnosis. The qualitative centrally restricted diffusion sign had a sensitivity of 69% (95% CI, .50-.83), specificity of 77% (95% CI, .40-.96), and a moderate (k = .49) inter-reader agreement for RN diagnosis. Conclusions: Radiation necrosis is associated with lower ADC values in the central necrosis than TR. A moderate interobserver agreement might limit the qualitative assessment of the centrally restricted diffusion sign.
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Affiliation(s)
- Paulo Puac-Polanco
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada
| | - Nader Zakhari
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada
| | - Jacob Miller
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada
| | - David McComiskey
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada
| | - Rebecca E Thornhill
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada
| | - Gerard H Jansen
- Department of Pathology and Laboratory Medicine, The Ottawa Hospital, 6363University of Ottawa, Ottawa, ON, Canada
| | - Vimoj J Nair
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada.,The Ottawa Hospital Research Institute (OHRI)
| | - Thanh Binh Nguyen
- Department of Radiology, Radiation Oncology and Medical Physics, 6363University of Ottawa, Ottawa, ON, Canada.,The Ottawa Hospital Research Institute (OHRI)
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6
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Chakwizira A, Westin C, Brabec J, Lasič S, Knutsson L, Szczepankiewicz F, Nilsson M. Diffusion MRI with pulsed and free gradient waveforms: Effects of restricted diffusion and exchange. NMR Biomed 2023; 36:e4827. [PMID: 36075110 PMCID: PMC10078514 DOI: 10.1002/nbm.4827] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 08/27/2022] [Accepted: 09/06/2022] [Indexed: 05/06/2023]
Abstract
Monitoring time dependence with diffusion MRI yields observables sensitive to compartment sizes (restricted diffusion) and membrane permeability (water exchange). However, restricted diffusion and exchange have opposite effects on the diffusion-weighted signal, which can lead to errors in parameter estimates. In this work, we propose a signal representation that incorporates the effects of both restricted diffusion and exchange up to second order in b-value and is compatible with gradient waveforms of arbitrary shape. The representation features mappings from a gradient waveform to two scalars that separately control the sensitivity to restriction and exchange. We demonstrate that these scalars span a two-dimensional space that can be used to choose waveforms that selectively probe restricted diffusion or exchange, eliminating the correlation between the two phenomena. We found that waveforms with specific but unconventional shapes provide an advantage over conventional pulsed and oscillating gradient acquisitions. We also show that parametrization of waveforms into a two-dimensional space can be used to understand protocols from other approaches that probe restricted diffusion and exchange. For example, we found that the variation of mixing time in filter-exchange imaging corresponds to variation of our exchange-weighting scalar at a fixed value of the restriction-weighting scalar. The proposed signal representation was evaluated using Monte Carlo simulations in identical parallel cylinders with hexagonal and random packing as well as parallel cylinders with gamma-distributed radii. Results showed that the approach is sensitive to sizes in the interval 4-12 μm and exchange rates in the simulated range of 0 to 20 s - 1 , but also that there is a sensitivity to the extracellular geometry. The presented theory constitutes a simple and intuitive description of how restricted diffusion and exchange influence the signal as well as a guide to protocol design capable of separating the two effects.
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Affiliation(s)
- Arthur Chakwizira
- Department of Medical Radiation Physics, LundLund UniversityLundSweden
| | - Carl‐Fredrik Westin
- Department of Radiology, Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Jan Brabec
- Department of Medical Radiation Physics, LundLund UniversityLundSweden
| | - Samo Lasič
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and ResearchCopenhagen University Hospital ‐ Amager and HvidovreCopenhagenDenmark
- Random Walk Imaging ABLundSweden
| | - Linda Knutsson
- Department of Medical Radiation Physics, LundLund UniversityLundSweden
- Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- F. M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMarylandUSA
| | | | - Markus Nilsson
- Department of Clinical Sciences Lund, RadiologyLund UniversityLundSweden
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7
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Gundogdu B, Pittman JM, Chatterjee A, Szasz T, Lee G, Giurcanu M, Medved M, Engelmann R, Guo X, Yousuf A, Antic T, Devaraj A, Fan X, Oto A, Karczmar GS. Directional and inter-acquisition variability in diffusion-weighted imaging and editing for restricted diffusion. Magn Reson Med 2022; 88:2298-2310. [PMID: 35861268 PMCID: PMC9545544 DOI: 10.1002/mrm.29385] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/15/2022] [Accepted: 06/21/2022] [Indexed: 11/23/2022]
Abstract
Purpose To evaluate and quantify inter‐directional and inter‐acquisition variation in diffusion‐weighted imaging (DWI) and emphasize signals that report restricted diffusion to enhance cancer conspicuity, while reducing the effects of local microscopic motion and magnetic field fluctuations. Methods Ten patients with biopsy‐proven prostate cancer were studied under an Institutional Review Board‐approved protocol. Individual acquisitions of DWI signal intensities were reconstructed to calculate inter‐acquisition distributions and their statistics, which were compared for healthy versus cancer tissue. A method was proposed to detect and filter the acquisitions affected by motion‐induced signal loss. First, signals that reflect restricted diffusion were separated from the acquisitions that suffer from signal loss, likely due to microscopic motion, by imposing a cutoff value. Furthermore, corrected apparent diffusion coefficient maps were calculated by employing a weighted sum of the multiple acquisitions, instead of conventional averaging. These weights were calculated by applying a soft‐max function to the set of acquisitions per‐voxel, making the analysis immune to acquisitions with significant signal loss, even if the number of such acquisitions is high. Results Inter‐acquisition variation is much larger than the Rician noise variance, local spatial variations, and the estimates of diffusion anisotropy based on the current data, as well as the published values of anisotropy. The proposed method increases the contrast for cancers and yields a sensitivity of 98.8% with a false positive rate of 3.9%. Conclusion Motion‐induced signal loss makes conventional signal‐averaging suboptimal and can obscure signals from areas with restricted diffusion. Filtering or weighting individual acquisitions prior to image analysis can overcome this problem. Click here for author‐reader discussions
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Affiliation(s)
- Batuhan Gundogdu
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Jay M Pittman
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | | | - Teodora Szasz
- Research Computing Center, University of Chicago, Chicago, Illinois, USA
| | - Grace Lee
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Mihai Giurcanu
- Department of Public Health Sciences, University of Chicago, Illinois, USA
| | - Milica Medved
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Roger Engelmann
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Xiaodong Guo
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Ambereen Yousuf
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Tatjana Antic
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
| | - Ajit Devaraj
- Philips Research North America, Cambridge, Massachusetts, USA
| | - Xiaobing Fan
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Aytekin Oto
- Department of Radiology, University of Chicago, Chicago, Illinois, USA
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Kuroda M, Konishi K, Sugimoto K, Yoshimura Y, Hamada K, Khasawnehc A, Barham M, Tekiki N, Sugianto I, Bamgbose BO, Ishizaka H, Shimizu Y, Nakamitsu Y, Al-Hammad WE, Kamizaki R, Kurozumi A, Matsushita T, Ohno S, Kanazawa S, Asaumi J. Evaluation of Fast Diffusion Kurtosis Imaging Using New Software Designed for Widespread Clinical Use. Acta Med Okayama 2022; 76:297-305. [PMID: 35790360 DOI: 10.18926/amo/63739] [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] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Clinical research using restricted diffusion-weighted imaging, especially diffusion kurtosis (DK) imaging, has been progressing, with reports on its effectiveness in the diagnostic imaging of cerebral infarctions, neurodegenerative diseases, and tumors, among others. However, the application of DK imaging in daily clinical practice has not spread because of the long imaging time required and the use of specific software for image creation. Herein, with the aim of promoting clinical research using DK imaging at any medical facility, we evaluated fast DK imaging using a new software program. We developed a new macro program that produces DK images using general-purpose, inexpensive software (Microsoft Excel and ImageJ), and we evaluated fast DK imaging using bio-phantoms and a healthy volunteer in clinical trials. The DK images created by the new software with diffusion-weighted images captured with short-time imaging sequences were similar to the original DK images captured with long-time imaging sequences. The DK images using three b-values, which can reduce the imaging time by 43%, were equivalent to the DK images using five b-values. The DK imaging technique developed herein might allow any medical facility to increase its daily clinical use of DK imaging and easily conduct clinical research.
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Affiliation(s)
- Masahiro Kuroda
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Kohei Konishi
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Kohei Sugimoto
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Yuuki Yoshimura
- Radiological Technology, Graduate School of Health Sciences, Okayama University
- Radiology Diagnosis, Okayama Saiseikai General Hospital
| | - Kentaro Hamada
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Abdullah Khasawnehc
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Majd Barham
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Nouha Tekiki
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Irfan Sugianto
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
- Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University
| | - Babatunde O Bamgbose
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
- Department of Oral Diagnostic Sciences, Faculty of Dentistry, Bayero University
| | - Hinata Ishizaka
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Yudai Shimizu
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Yuki Nakamitsu
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Wlla E Al-Hammad
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Ryo Kamizaki
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Akira Kurozumi
- Central Division of Radiology, Okayama University Hospital
| | | | - Seiichiro Ohno
- Central Division of Radiology, Okayama University Hospital
| | - Susumu Kanazawa
- Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Junichi Asaumi
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
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Aboud O, Shah R, Vera E, Burton E, Theeler B, Wu J, Boris L, Quezado M, Reyes J, Wall K, R Gilbert M, S Armstrong T, Penas-Prado M. Challenges of imaging interpretation to predict oligodendroglioma grade: a report from the Neuro-Oncology Branch. CNS Oncol 2022; 11:CNS83. [PMID: 35142534 PMCID: PMC8988255 DOI: 10.2217/cns-2021-0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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] [Indexed: 01/04/2023] Open
Abstract
Background: To illustrate challenges of imaging interpretation in patients with oligodendroglioma seen at a referral center and evaluate interrater reliability. Methods: Two neuro-oncologists reviewed diagnostic preradiation MRIs of oligodendroglioma patients; interrater reliability was calculated with the kappa coefficient (k). A neuroradiologist measured presurgical apparent diffusion coefficient (ADC), if available. Results: Extensive enhancement was noted in four of 58 patients, k = 0.7; necrosis in seven of 58, k = 0.61; calcification in seven of 17, k = 1.0; diffusion restriction in two of 39 patients, k = 1.0 (all only in grade 3). ADC values with receiver operator characteristic analysis for area under the curve were 0.473, not significantly different from the null hypothesis (p = 0.14). Conclusions: Extensive enhancement, necrosis and calcification correlated with grade 3 oligodendroglioma in our sample. However, interrater variability is an important limitation when assessing radiographic features, supporting the need for standardization of imaging protocols and their interpretation.
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Affiliation(s)
- Orwa Aboud
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.,UC Davis Comprehensive Cancer Center, University of California Davis, Sacramento, CA 95817, USA
| | - Ritu Shah
- Department of Neuro radiology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Elizabeth Vera
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Eric Burton
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Brett Theeler
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.,Walter Reed National Military Medical Center, Bethesda, MD 20814, USA
| | - Jing Wu
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Lisa Boris
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Martha Quezado
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814 USA
| | - Jennifer Reyes
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Kathleen Wall
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Mark R Gilbert
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Terri S Armstrong
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Marta Penas-Prado
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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10
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Sugimoto K, Kuroda M, Yoshimura Y, Hamada K, Khasawneh A, Barham M, Tekiki N, Konishi K, Ishizaka H, Shimizu Y, Nakamitsu Y, Al-Hammad WE, Kamizaki R, Kanazawa S, Asaumi J. Development and Evaluation of a Short-time Imaging Method for the Clinical Study of the Apparent Diffusion Coefficient Subtraction Method. Acta Med Okayama 2022; 76:25-32. [PMID: 35236995 DOI: 10.18926/amo/63205] [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] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The apparent diffusion coefficient subtraction method (ASM) was developed as a new restricted diffusionweighted imaging technique for magnetic resonance imaging (MRI). The usefulness of the ASM has been established by in vitro basic research using a bio-phantom, and clinical research on the application of the ASM for the human body is needed. Herein, we developed a short-time sequence for ASM imaging of the heads of healthy volunteers (n=2), and we investigated the similarity between the obtained ASM images and diffusion kurtosis (DK) images to determine the utility of the ASM for clinical uses. This study appears to be the first to report ASM images of the human head. We observed that the short-time sequence for the ASM imaging of the head can be scanned in approx. 3 min at 1.5T MRI. The noise reduction effect of median filter processing was confirmed on the ASM images scanned by this sequence. The obtained ASM images showed a weak correlation with the DK images, indicating that the ASM images are restricted diffusion-weighted images. The new shorttime imaging sequence could thus be used in clinical studies applying the ASM.
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Affiliation(s)
- Kohei Sugimoto
- Radiological Technology, Graduate School of Health Sciences, Okayama University
- Divisions of Imaging Technology, Okayama Diagnostic Imaging Center
| | - Masahiro Kuroda
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Yuuki Yoshimura
- Radiological Technology, Graduate School of Health Sciences, Okayama University
- Radiology Diagnosis, Okayama Saiseikai General Hospital
| | - Kentaro Hamada
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Abdullah Khasawneh
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Majd Barham
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Nouha Tekiki
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Kohei Konishi
- Radiological Technology, Graduate School of Health Sciences, Okayama University
- Department of Radiology, Red Cross Okayama Hospital
| | - Hinata Ishizaka
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Yudai Shimizu
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Yuki Nakamitsu
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Wlla E Al-Hammad
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Ryo Kamizaki
- Radiological Technology, Graduate School of Health Sciences, Okayama University
| | - Susumu Kanazawa
- Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Junichi Asaumi
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
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11
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Michael ES, Hennel F, Pruessmann KP. Evaluating diffusion dispersion across an extended range of b-values and frequencies: Exploiting gap-filled OGSE shapes, strong gradients, and spiral readouts. Magn Reson Med 2022; 87:2710-2723. [PMID: 35049104 PMCID: PMC9306807 DOI: 10.1002/mrm.29161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 06/24/2021] [Revised: 12/29/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022]
Abstract
Purpose To address the long echo times and relatively weak diffusion sensitization that typically limit oscillating gradient spin‐echo (OGSE) experiments, an OGSE implementation combining spiral readouts, gap‐filled oscillating gradient shapes providing stronger diffusion encoding, and a high‐performance gradient system is developed here and utilized to investigate the tradeoff between b‐value and maximum OGSE frequency in measurements of diffusion dispersion (i.e., the frequency dependence of diffusivity) in the in vivo human brain. In addition, to assess the effects of the marginal flow sensitivity introduced by these OGSE waveforms, flow‐compensated variants are devised for experimental comparison. Methods Using DTI sequences, OGSE acquisitions were performed on three volunteers at b‐values of 300, 500, and 1000 s/mm2 and frequencies up to 125, 100, and 75 Hz, respectively; scans were performed for gap‐filled oscillating gradient shapes with and without flow sensitivity. Pulsed gradient spin‐echo DTI acquisitions were also performed at each b‐value. Upon reconstruction, mean diffusivity (MD) maps and maps of the diffusion dispersion rate were computed. Results The power law diffusion dispersion model was found to fit best to MD measurements acquired at b = 1000 s/mm2 despite the associated reduction of the spectral range; this observation was consistent with Monte Carlo simulations. Furthermore, diffusion dispersion rates without flow sensitivity were slightly higher than flow‐sensitive measurements. Conclusion The presented OGSE implementation provided an improved depiction of diffusion dispersion and demonstrated the advantages of measuring dispersion at higher b‐values rather than higher frequencies within the regimes employed in this study.
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Affiliation(s)
- Eric Seth Michael
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Franciszek Hennel
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas Paul Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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12
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Cai TX, Williamson NH, Ravin R, Basser PJ. Disentangling the effects of restriction and exchange with diffusion exchange spectroscopy. Front Phys 2022; 10:805793. [PMID: 37063496 PMCID: PMC10104504 DOI: 10.3389/fphy.2022.805793] [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: 05/17/2023]
Abstract
Diffusion exchange spectroscopy (DEXSY) is a multidimensional NMR technique that can reveal how water molecules exchange between compartments within heterogeneous media, such as biological tissue. Data from DEXSY experiments is typically processed using numerical inverse Laplace transforms (ILTs) to produce a diffusion-diffusion spectrum. A tacit assumption of this ILT approach is that the signal behavior is Gaussian - i.e., the spin echo intensity decays exponentially with the degree of diffusion weighting. The assumptions that underlie Gaussian signal behavior may be violated, however, depending on the gradient strength applied and the sample under study. We argue that non-Gaussian signal behavior due to restrictions is to be expected in the study of biological tissue using diffusion NMR. Further, we argue that this signal behavior can produce confounding features in the diffusion-diffusion spectra obtained from numerical ILTs of DEXSY data - entangling the effects of restriction and exchange. Specifically, restricted signal behavior can result in broadening of peaks and in the appearance of illusory exchanging compartments with distributed diffusivities, which pearl into multiple peaks if not highly regularized. We demonstrate these effects on simulated data. That said, we suggest the use of features in the signal acquisition domain that can be used to rapidly probe exchange without employing an ILT. We also propose a means to characterize the non-Gaussian signal behavior due to restrictions within a sample using DEXSY measurements with a near zero mixing time or storage interval. We propose a combined acquisition scheme to independently characterize restriction and exchange with various DEXSY measurements, which we term Restriction and Exchange from Equally-weighted Double and Single Diffusion Encodings (REEDS-DE). We test this method on ex vivo neonatal mouse spinal cord - a sample consisting primarily of gray matter - using a low-field, static gradient NMR system. In sum, we highlight critical shortcomings of prevailing DEXSY analysis methods that conflate the effects of restriction and exchange, and suggest a viable experimental approach to disentangle them.
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Affiliation(s)
- Teddy X. Cai
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Nathan H. Williamson
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Rea Ravin
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Celoptics, Rockville, Maryland, USA
| | - Peter J. Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Correspondence: Peter J. Basser, Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 13, Room 3W16, 13 South Drive, Bethesda, Maryland 20892-5772, USA,
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13
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Abstract
Background: Restricted diffusion within the splenium of the corpus callosum has been described by other authors in various conditions, however, restricted diffusion in the entire corpus callosum or isolated involvement of the splenium, genu, or body has been infrequently reported on magnetic resonance imaging (MRI) in neonatal hypoxic–ischemic encephalopathy. We report a series of cases showing different patterns of involvement. Methods and Materials: Perinatal imaging with MRI including diffusion-weighted imaging was performed in 40 neonates with hypoxic–ischemic encephalopathy, including 11 premature neonates. Sixteen out of 40 patients demonstrated restricted diffusion within the corpus callosum. Out of 16 patients, 9 showed restricted diffusion in the entire corpus callosum, 4 had isolated splenium involvement, 2 had body and splenium signal abnormality, and 1 showed diffusion restriction only in the genu. Conclusions: Changes in the corpus callosum were also associated with more severe clinical presentation of encephalopathy. Restricted diffusion within the corpus callosum in infants with hypoxic–ischemic encephalopathy is often associated with extensive brain injury and appears to be an early neuroradiologic marker of adverse neurologic outcome.
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Affiliation(s)
- Alok Kale
- Department of Radiodiagnosis and Imaging, Bharati Hospital and Research Center, Pune, Maharashtra, India
| | - Priscilla Joshi
- Department of Radiodiagnosis and Imaging, Bharati Hospital and Research Center, Pune, Maharashtra, India
| | - A B Kelkar
- Department of Radiodiagnosis and Imaging, Bharati Hospital and Research Center, Pune, Maharashtra, India
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14
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Saito Y. Ion Transport in Solid Medium-Evaluation of Ionic Mobility for Design of Ion Transport Pathways in Separator and Gel Electrolyte. Membranes (Basel) 2021; 11:membranes11040277. [PMID: 33918890 PMCID: PMC8069590 DOI: 10.3390/membranes11040277] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/16/2022]
Abstract
Further improvement in the performance of lithium secondary batteries will be an indispensable issue to realize a decarbonized society. Among them, the batteries for electric vehicles still have many issues to be addressed because they are subject to various conditions such as high-power performance, safety, and cost restrictions for widespread use. Those subjects require extensive researches from the improvement of each element material to control the battery system to optimize the total performance. Based on this idea, we have been conducting research focusing on ion movement to elucidate the ion conduction mechanism from the microscopic point of view. It has been recognized that the ionic mobility in the battery, which dominates the power performance of the battery, is affected by the solid environment in which the ions move (separator and electrode materials) and the evaluation of ion movement, including the interaction with the surroundings, is necessary as an essential step for battery design. In this article, I will introduce the evaluation approach of ion dynamics and the evaluation results of mobility and interactive situations of carrier ions in the practical separator membranes and gel electrolytes. Finally, the direction of material design is outlined through this review.
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Affiliation(s)
- Yuria Saito
- Separator Design Co. Ltd. 1725-1, Hagyu, Ooaza, Iide-machi, Yamagata 999-0602, Japan; ; Tel.: +81-238-88-7755
- National Institute of Advanced Industrial Science & Technology 1-8-31, Midorigaoka, Ikeda 563-8577, Japan
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15
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Hennel F, Michael ES, Pruessmann KP. Improved gradient waveforms for oscillating gradient spin-echo (OGSE) diffusion tensor imaging. NMR Biomed 2021; 34:e4434. [PMID: 33124071 DOI: 10.1002/nbm.4434] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 06/18/2020] [Revised: 09/11/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
The dependence of the diffusion tensor on frequency is of great interest in studies of tissue microstructure because it reveals restrictions to the Brownian motion of water molecules caused by cell membranes. Oscillating gradient spin-echo (OGSE) sequences can sample this dependence with gradient shapes for which the power spectrum of the zeroth moment is focused at a target frequency. In order to maintain the total spectral power (ie the b-value), oscillating gradient amplitudes must grow with the frequency squared. For this reason, OGSE applications on clinical MRI scanners are limited to low frequencies, for which it is difficult to obtain a narrow frequency bandwidth of the gradient moment in a useful echo time. In particular, the commonly used pair of single-period trapezoidal-cosine pulses separated by a half-period produces significant side lobes away from the target frequency. To mitigate this effect, improved OGSE waveforms are proposed, which reduce the gap between the two gradient pulses to the minimum duration required for the refocusing RF pulse. Additionally, a slight deviation from the periodicity of the waveforms is proposed in order to permit using the maximum slew rate of the gradient system for all lobes of trapezoidal waveforms while maintaining advantageous spectral properties, which is not the case for the currently used OGSE sequences. Numerical calculations validate these changes, showing that both modifications significantly narrow the gradient moment power spectrum and increase the contribution of its main lobe to the b-value, thus improving the specificity of the measurement. The utility of the new shapes is demonstrated by diffusion tensor measurements of human white matter in vivo over the range of 30-75 Hz with a b-value of nearly 1000 s/mm2 , using a high-performance gradient insert. However, the improvement should increase the sampling precision of OGSE experiments for all gradient systems.
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Affiliation(s)
- Franciszek Hennel
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Eric Seth Michael
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
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16
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Mahajan A, Komonchan S, Na Songkhla K, Boontaworn A, Nosai S. Dramatic motor recovery following recanalization in bilateral pontine infarct with restricted diffusion. Clin Case Rep 2020; 8:2574-2577. [PMID: 33363782 PMCID: PMC7752632 DOI: 10.1002/ccr3.3225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 04/02/2020] [Revised: 06/08/2020] [Accepted: 07/16/2020] [Indexed: 11/10/2022] Open
Abstract
On findings of restricted diffusion in a bilateral pontine infarct, imaging solely may not predict a poor clinical outcome as a full motor recovery is possible. Hence, recanalization of an acutely occluded basilar artery should be carefully considered on a case by case basis.
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Affiliation(s)
- Arnav Mahajan
- Department of NeurologyPrasat Neurological InstituteBangkokThailand
| | | | | | | | - Supalak Nosai
- Department of NeuroradiologyPrasat Neurological InstituteBangkokThailand
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17
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Khasawneh A, Kuroda M, Yoshimura Y, Sugianto I, Bamgbose BO, Hamada K, Barham M, Tekiki N, Konishi K, Sugimoto K, Ishizaka H, Kurozumi A, Matsushita T, Ohno S, Kanazawa S, Asaumi J. Development of a novel phantom using polyethylene glycol for the visualization of restricted diffusion in diffusion kurtosis imaging and apparent diffusion coefficient subtraction method. Biomed Rep 2020; 13:52. [PMID: 33082949 DOI: 10.3892/br.2020.1359] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 09/03/2020] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to investigate whether polyethylene glycol (PEG) phantoms have the potential to be used as standard phantoms for magnetic resonance imaging (MRI) in order to visualize restricted diffusion in diffusion kurtosis imaging (DKI), the ADC subtraction method (ASM) and the apparent diffusion coefficient (ADC). Diffusion-weighted images of 0-120 mM PEG phantoms were captured to create ADC, DKI and ASM images with post-processing. ASM is a recently developed method for restricted diffusion imaging using the readout segmentation of long variable echo-train sequences. As the PEG concentration increases, the ADC value decreases. Conversely, an increase in DKI and ASM values is associated with increasing PEG concentration. Formulae were constructed to represent the association between PEG concentrations and ADC, DKI and ASM values. These formulae can be used to determine the required PEG concentrations to mimic arbitrary ADC, DKI and ASM values of certain diseases, including tumors and infarctions. Validation experiments were conducted using bio-phantoms and clarified that the PEG phantoms cover the range of ADC and DKI values reported in previous clinical research using 3T MRI. PEG phantoms may be useful for future MRI research involving restricted diffusion.
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Affiliation(s)
- Abdullah Khasawneh
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
| | - Masahiro Kuroda
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
| | - Yuuki Yoshimura
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan.,Department of Radiology Diagnosis, Okayama Saiseikai General Hospital, Okayama 700-8511, Japan
| | - Irfan Sugianto
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan.,Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University, Makassar, Sulawesi Selatan 90245, Indonesia
| | - Babatunde O Bamgbose
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
| | - Kentaro Hamada
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
| | - Majd Barham
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
| | - Nouha Tekiki
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
| | - Kohei Konishi
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
| | - Kohei Sugimoto
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
| | - Hinata Ishizaka
- Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
| | - Akira Kurozumi
- Central Division of Radiology, Okayama University Hospital, Okayama 700-8558, Japan
| | - Toshi Matsushita
- Central Division of Radiology, Okayama University Hospital, Okayama 700-8558, Japan
| | - Seiichiro Ohno
- Central Division of Radiology, Okayama University Hospital, Okayama 700-8558, Japan
| | - Susumu Kanazawa
- Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Junichi Asaumi
- Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
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18
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Brabec J, Lasič S, Nilsson M. Time-dependent diffusion in undulating thin fibers: Impact on axon diameter estimation. NMR Biomed 2020; 33:e4187. [PMID: 31868995 PMCID: PMC7027526 DOI: 10.1002/nbm.4187] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 02/04/2019] [Revised: 08/03/2019] [Accepted: 08/19/2019] [Indexed: 05/22/2023]
Abstract
Diffusion MRI may enable non-invasive mapping of axonal microstructure. Most approaches infer axon diameters from effects of time-dependent diffusion on the diffusion-weighted MR signal by modeling axons as straight cylinders. Axons do not, however, propagate in straight trajectories, and so far the impact of the axonal trajectory on diameter estimation has been insufficiently investigated. Here, we employ a toy model of axons, which we refer to as the undulating thin fiber model, to analyze the impact of undulating trajectories on the time dependence of diffusion. We study time-dependent diffusion in the frequency domain and characterize the diffusion spectrum by its height, width, and low-frequency behavior (power law exponent). Results show that microscopic orientation dispersion of the thin fibers is the main parameter that determines the characteristics of the diffusion spectra. At lower frequencies (longer diffusion times), straight cylinders and undulating thin fibers can have virtually identical spectra. If the straight-cylinder assumption is used to interpret data from undulating thin axons, the diameter is overestimated by an amount proportional to the undulation amplitude and microscopic orientation dispersion of the fibers. At higher frequencies (shorter diffusion times), spectra from cylinders and undulating thin fibers differ. The low-frequency behavior of the spectra from the undulating thin fibers may also differ from that of cylinders, because the power law exponent of undulating fibers can reach values below 2 for experimentally relevant frequency ranges. In conclusion, we argue that the non-straight nature of axonal trajectories should not be overlooked when analyzing and interpreting diffusion MRI data.
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Affiliation(s)
- Jan Brabec
- Department of Clinical Sciences Lund, Medical Radiation PhysicsLund UniversityLundSweden
| | | | - Markus Nilsson
- Department of Clinical Sciences Lund, Diagnostic RadiologyLund UniversityLundSweden
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19
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Golemme G, Santaniello A. Perfluoropolymer/Molecular Sieve Mixed-Matrix Membranes. Membranes (Basel) 2019; 9:E19. [PMID: 30678094 PMCID: PMC6410318 DOI: 10.3390/membranes9020019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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] [Received: 12/30/2018] [Revised: 01/19/2019] [Accepted: 01/21/2019] [Indexed: 11/16/2022]
Abstract
Despite the outstanding chemical, thermal and transport properties of amorphous and glassy perfluorinated polymers, only few works exist on the preparation and transport properties of perfluoropolymer/molecular sieves mixed-matrix membranes (MMMs), probably because of their poor compatibility. In this review, the compatibilization of ceramic molecular sieves with perfluorinated matrices is considered first, examining the effect of the surface treatment on the gas transport properties of the filler. Then the preparation of the defect-free hybrid membranes and their gas separation capabilities are described. Finally, recent modelling of the gas transport properties of the perfluoropolymer MMMs is reviewed. The systematic use of molecular sieves of different size and shape, either permeable or impermeable, and the calculation of the bulk transport properties of the molecular sieves-i.e., the unrestricted diffusion and permeability-allow to understand the nature of the physical phenomena at work in the MMMs, that is the larger the perfluoropolymer fractional free volume at the interface, and restricted diffusion at the molecular sieves. This knowledge led to the formulation of a new four-phase approach for the modelling of gas transport. The four-phase approach was implemented in the frame of the Maxwell model and also for the finite element simulation. The four-phase approach is a convenient representation of the transport in MMMs when more than one single interfacial effect is present.
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Affiliation(s)
- Gianni Golemme
- Department of Environmental and Chemical Engineering, University of Calabria, Via P. Bucci 45 A, 87036 Rende, Italy.
| | - Anna Santaniello
- Physics Department, University of Calabria, Via P. Bucci 22 C, 87036 Rende, Italy.
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20
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Ciesielski R, Schäfer F, Hartmann NF, Giesbrecht N, Bein T, Docampo P, Hartschuh A. Grain Boundaries Act as Solid Walls for Charge Carrier Diffusion in Large Crystal MAPI Thin Films. ACS Appl Mater Interfaces 2018; 10:7974-7981. [PMID: 29433313 DOI: 10.1021/acsami.7b17938] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Micro- and nanocrystalline methylammonium lead iodide (MAPI)-based thin-film solar cells today reach power conversion efficiencies of over 20%. We investigate the impact of grain boundaries on charge carrier transport in large crystal MAPI thin films using time-resolved photoluminescence (PL) microscopy and numerical model calculations. Crystal sizes in the range of several tens of micrometers allow for the spatially and time resolved study of boundary effects. Whereas long-ranged diffusive charge carrier transport is observed within single crystals, no detectable diffusive transport occurs across grain boundaries. The observed PL transients are found to crucially depend on the microscopic geometry of the crystal and the point of observation. In particular, spatially restricted diffusion of charge carriers leads to slower PL decay near crystal edges as compared to the crystal center. In contrast to many reports in the literature, our experimental results show no quenching or additional loss channels due to grain boundaries for the studied material, which thus do not negatively affect the performance of the derived thin-film devices.
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Affiliation(s)
- Richard Ciesielski
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
| | - Frank Schäfer
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
| | - Nicolai F Hartmann
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
| | - Nadja Giesbrecht
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
| | - Thomas Bein
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
| | - Pablo Docampo
- School of Electrical and Electronic Engineering , Newcastle University , Merz Court, NE1 7RU Newcastle upon Tyne , U.K
| | - Achim Hartschuh
- Department of Chemistry and Center for NanoScience (CeNS) , LMU Munich , Butenandtstr. 5-13 , 81377 Munich , Germany
- Nanosystems Initiative Munich (NIM) , LMU Munich , Schellingstr. 4 , 80799 Munich , Germany
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21
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Andica C, Hori M, Kamiya K, Koshino S, Hagiwara A, Kamagata K, Fukunaga I, Hamasaki N, Suzuki M, Feiweier T, Murata K, Arakawa A, Kondo A, Akiyama O, Aoki S. Spatial Restriction within Intracranial Epidermoid Cysts Observed Using Short Diffusion-time Diffusion-weighted Imaging. Magn Reson Med Sci 2017; 17:269-272. [PMID: 29129844 PMCID: PMC6039784 DOI: 10.2463/mrms.cr.2017-0111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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] [Indexed: 11/17/2022] Open
Abstract
We report two cases of pathologically proven intracranial epidermoid cysts. Both cases were scanned with diffusion-weighted imaging using pulsed gradient spin-echo (PGSE) and oscillating gradient spin-echo (OGSE; 50 Hz) prototype sequences with diffusion times of 47.3 ms and 8.5 ms, respectively. The apparent diffusion coefficient measured by OGSE was higher than that measured by PGSE, indicating the spatial restriction of water diffusion in the laminated keratin layers within the cyst as demonstrated by histopathology.
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Affiliation(s)
- Christina Andica
- Department of Radiology, Juntendo University Graduate School of Medicine
| | - Masaaki Hori
- Department of Radiology, Juntendo University Graduate School of Medicine
| | - Kouhei Kamiya
- Department of Radiology, Graduate School of Medicine, The University of Tokyo
| | - Saori Koshino
- Department of Radiology, Juntendo University Graduate School of Medicine.,Department of Radiology, Graduate School of Medicine, The University of Tokyo
| | - Akifumi Hagiwara
- Department of Radiology, Juntendo University Graduate School of Medicine.,Department of Radiology, Graduate School of Medicine, The University of Tokyo
| | - Koji Kamagata
- Department of Radiology, Juntendo University Graduate School of Medicine
| | - Issei Fukunaga
- Department of Radiology, Juntendo University Graduate School of Medicine
| | - Nozomi Hamasaki
- Department of Radiology, Juntendo University Graduate School of Medicine
| | - Michimasa Suzuki
- Department of Radiology, Juntendo University Graduate School of Medicine
| | | | | | - Atsushi Arakawa
- Department of Human Pathology, Juntendo University School of Medicine
| | - Akihide Kondo
- Department of Neurosurgery, Juntendo University School of Medicine
| | - Osamu Akiyama
- Department of Neurosurgery, Juntendo University School of Medicine
| | - Shigeki Aoki
- Department of Radiology, Juntendo University Graduate School of Medicine
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22
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Abstract
PURPOSE This work describes the development of a method to measure the variation of apparent diffusion coefficient (ADC) with diffusion time (Δ) in the brachial plexus, as a potential method of probing microstructure. METHODS Diffusion-weighted MRI with body signal suppression was used to highlight the nerves from surrounding tissues, and sequence parameters were optimized for sensitivity to change with diffusion time. A porous media-restricted diffusion model based on the Latour-Mitra equation was fitted to the diffusion time-dependent ADC data from the brachial plexus nerves and cord. RESULTS The ADC was observed to reduce at long diffusion times, confirming that diffusion was restricted in the nerves and cord in healthy subjects. T2 of the nerves was measured to be 80 ± 5 ms, the diffusion coefficient was found to vary from (1.5 ± 0.1) × 10-3 mm2 /s at a diffusion time of 18.3 ms to (1.0 ± 0.2) × 10-3 mm2 /s at a diffusion time of 81.3 ms. CONCLUSION A novel method of probing restricted diffusion in the brachial plexus was developed. Resulting parameters were comparable with values obtained previously on biological systems. Magn Reson Med 79:789-795, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zaid B Mahbub
- Department of Arts & Sciences, Ahsanullah University of Science & Technology, Dhaka, Bangladesh.,Sir Peter Mansfield Imaging Centre, School of Physics & Astronomy, University of Nottingham, United Kingdom
| | - Andrew M Peters
- Sir Peter Mansfield Imaging Centre, School of Physics & Astronomy, University of Nottingham, United Kingdom
| | - Penny A Gowland
- Sir Peter Mansfield Imaging Centre, School of Physics & Astronomy, University of Nottingham, United Kingdom
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23
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Scalais E, Osterheld E, Weitzel C, De Meirleir L, Mataigne F, Martens G, Shaikh TH, Coughlin CR, Yu HC, Swanson M, Friederich MW, Scharer G, Helbling D, Wendt-Andrae J, Van Hove JLK. X-Linked Cobalamin Disorder (HCFC1) Mimicking Nonketotic Hyperglycinemia With Increased Both Cerebrospinal Fluid Glycine and Methylmalonic Acid. Pediatr Neurol 2017; 71:65-69. [PMID: 28363510 DOI: 10.1016/j.pediatrneurol.2016.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 11/23/2016] [Accepted: 12/03/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND Autosomal recessive or X-linked inborn errors of intracellular cobalamin metabolism can lead to methylmalonic aciduria and homocystinuria. In neonates, both increased cerebrospinal fluid glycine and cerebrospinal fluid/plasma glycine ratio are biochemical features of nonketotic hyperglycinemia. METHODS We describe a boy presenting in the neonatal period with hypotonia, tonic, clonic, and later myoclonic seizures, subsequently evolving into refractory epilepsy and severe neurocognitive impairment. RESULTS Increased cerebrospinal fluid glycine and cerebrospinal fluid to plasma glycine ratio were indicative of nonketotic hyperglycinemia. Early magnetic resonance imaging showed restricted diffusion and decreased apparent diffusion coefficient values in posterior limb of internal capsules and later in entire internal capsules and posterior white matter. Sequencing did not show a mutation in AMT, GLDC, or GCSH. Biochemical analysis identified persistently increased cerebrospinal fluid levels of glycine and methylmalonic acid and increased urinary methylmalonic acid and plasma homocysteine levels, which improved on higher parenteral hydroxocobalamin dose. Exome sequencing identified a known pathogenic sequence variant in X-linked cobalamin (HCFC1), c.344C>T, p. Ala115Val. In addition, a hemizygous mutation was found in the ATRX (c. 2728A>G, p. Lys910Glu). Retrospective review of two other patients with X-linked cobalamin deficiency also identified increased cerebrospinal fluid glycine levels. CONCLUSIONS This boy had X-linked cobalamin deficiency (HCFC1) with increased cerebrospinal fluid glycine and methylmalonic acid and increased cerebrospinal fluid to plasma glycine ratio suggesting a brain hyperglycinemia. Putative binding sites for HCFC1 and its binding partner THAP11 were identified near genes of the glycine cleavage enzyme, providing a potential mechanistic link between HCFC1 mutations and increased glycine.
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Affiliation(s)
- Emmanuel Scalais
- Division of Pediatric Neurology, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg; Department of Pediatrics, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg.
| | - Elise Osterheld
- Division of Pediatric Neurology, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg; Department of Pediatrics, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | - Christiane Weitzel
- Department of Pediatrics, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | - Linda De Meirleir
- Pediatric Neurology and Metabolism, Universitair Ziekenhuis, Brussel, Belgium
| | - Frederic Mataigne
- Department of Neuroradiology, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | - Geert Martens
- VUB Metabolomics Platform, Department of Clinical Biology, Universitair Ziekenhuis, Brussel, Belgium
| | - Tamim H Shaikh
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Curtis R Coughlin
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Hung-Chun Yu
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Michael Swanson
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Marisa W Friederich
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Gunter Scharer
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin; Molecular Genetics Supervisor, Sequencing Core Diagnostic Manager, Human Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Daniel Helbling
- Molecular Genetics Supervisor, Sequencing Core Diagnostic Manager, Human Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jamie Wendt-Andrae
- Molecular Genetics Supervisor, Sequencing Core Diagnostic Manager, Human Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Johan L K Van Hove
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado.
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24
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Zubkov M, Dennis GR, Stait-Gardner T, Torres AM, Willis SA, Zheng G, Price WS. Physical characterization using diffusion NMR spectroscopy. Magn Reson Chem 2017; 55:414-424. [PMID: 27657736 DOI: 10.1002/mrc.4530] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/16/2016] [Accepted: 09/19/2016] [Indexed: 06/06/2023]
Abstract
NMR diffusion measurements (or dNMR) provide a powerful tool for analysis of solution organization and microgeometry of the environment by probing random molecular motion. Being a very versatile method, dNMR can be applied to a large variety of samples and systems. Here, a brief introduction into dNMR and a summary of recent advances in the field are presented. The research topics include restricted diffusion, anisotropic diffusion, polymer dynamics, solution structuring and dNMR method development. The dNMR studied systems include plants, cells (cell models), liquid crystals, polymer solutions, ionic liquids, supercooled solutions, untreated water, amino acid solutions and more. It is demonstrated how a variety of dNMR methods can be applied to a system to extract the data on particular structures present among, formed by or surrounding the diffusing particles. It is also demonstrated how dNMR methods can be developed to allow probing larger geometries, low sample concentrations and faster processes. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Mikhail Zubkov
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Gary R Dennis
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Tim Stait-Gardner
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Allan M Torres
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Scott A Willis
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Gang Zheng
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - William S Price
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
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25
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Karnan S, Krishnamoorthy V, Natarajan K, Sathyanathan BP. Confounding features of ectopic craniopharyngioma: A differential for tumors showing diffusion restriction. Asian J Neurosurg 2017; 12:123-126. [PMID: 28413554 PMCID: PMC5379785 DOI: 10.4103/1793-5482.149999] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Craniopharyngiomas comprise approximately 1-3% of all intracranial tumors and arise from squamous epithelial rests along remnants of Rathke's cleft. They have bimodal age distribution. The ectopic sites reported are the nasopharynx, sphenoid bone, pineal region, cerebellopontine angle and third ventricle. We report a case of ectopic craniopharyngioma in the Foramen of Monro with restricted diffusion, which have is an unusual feature, not commonly reported and is a potential pitfall.
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Affiliation(s)
- Sudha Karnan
- Barnard Institute of Radiology, Madras Medical College, Chennai, Tamil Nadu, India
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26
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Hope TR, White NS, Kuperman J, Chao Y, Yamin G, Bartch H, Schenker-Ahmed NM, Rakow-Penner R, Bussell R, Nomura N, Kesari S, Bjørnerud A, Dale AM. Demonstration of Non-Gaussian Restricted Diffusion in Tumor Cells Using Diffusion Time-Dependent Diffusion-Weighted Magnetic Resonance Imaging Contrast. Front Oncol 2016; 6:179. [PMID: 27532028 PMCID: PMC4970563 DOI: 10.3389/fonc.2016.00179] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 09/18/2015] [Accepted: 07/19/2016] [Indexed: 12/31/2022] Open
Abstract
The diffusion-weighted magnetic resonance imaging (DWI) technique enables quantification of water mobility for probing microstructural properties of biological tissue and has become an effective tool for collecting information about the underlying pathology of cancerous tissue. Measurements using multiple b-values have indicated biexponential signal attenuation, ascribed to “fast” (high ADC) and “slow” (low ADC) diffusion components. In this empirical study, we investigate the properties of the diffusion time (Δ)-dependent components of the diffusion-weighted (DW) signal in a constant b-value experiment. A xenograft gliobastoma mouse was imaged using Δ = 11 ms, 20 ms, 40 ms, 60 ms, and b = 500–4000 s/mm2 in intervals of 500 s/mm2. Data were corrected for EPI distortions, and the Δ-dependence on the DW-signal was measured within three regions of interest [intermediate- and high-density tumor regions and normal-appearing brain (NAB) tissue regions]. In this study, we verify the assumption that the slow decaying component of the DW-signal is non-Gaussian and dependent on Δ, consistent with restricted diffusion of the intracellular space. As the DW-signal is a function of Δ and is specific to restricted diffusion, manipulating Δ at constant b-value (cb) provides a complementary and direct approach for separating the restricted from the hindered diffusion component. We found that Δ-dependence is specific to the tumor tissue signal. Based on an extended biexponential model, we verified the interpretation of the diffusion time-dependent contrast and successfully estimated the intracellular restricted ADC, signal volume fraction, and cell size within each ROI.
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Affiliation(s)
- Tuva R Hope
- The Interventional Centre, Oslo University Hospital, Oslo, Norway; Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nathan S White
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | - Joshua Kuperman
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | - Ying Chao
- Department of Neurosciences, University of California San Diego , La Jolla, CA , USA
| | - Ghiam Yamin
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | - Hauke Bartch
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | | | - Rebecca Rakow-Penner
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | - Robert Bussell
- Department of Radiology, University of California San Diego , La Jolla, CA , USA
| | - Natsuko Nomura
- Department of Neurosciences, University of California San Diego , La Jolla, CA , USA
| | - Santosh Kesari
- Department of Neurosciences, University of California San Diego , La Jolla, CA , USA
| | - Atle Bjørnerud
- The Interventional Centre, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway
| | - Anders M Dale
- Department of Radiology, University of California San Diego, La Jolla, CA, USA; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
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27
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Abstract
In vivo voltammetry reveals substantial diversity of dopamine kinetics in the rat striatum. To substantiate this kinetic diversity, we evaluate the temporal distortion of dopamine measurements arising from the diffusion-limited adsorption of dopamine to voltammetric microelectrodes. We validate two mathematical procedures for correcting adsorptive distortion, both of which substantiate that dopamine's apparent kinetic diversity is not an adsorption artifact.
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Affiliation(s)
- Seth H. Walters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Elaine M. Robbins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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28
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Liang S, Panagiotaki E, Bongers A, Shi P, Sved P, Watson G, Bourne R. Information-based ranking of 10 compartment models of diffusion-weighted signal attenuation in fixed prostate tissue. NMR Biomed 2016; 29:660-671. [PMID: 26999065 DOI: 10.1002/nbm.3510] [Citation(s) in RCA: 8] [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: 11/17/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 06/05/2023]
Abstract
This study compares the theoretical information content of single- and multi-compartment models of diffusion-weighted signal attenuation in prostate tissue. Diffusion-weighted imaging (DWI) was performed at 9.4 T with multiple diffusion times and an extended range of b values in four whole formalin-fixed prostates. Ten models, including different combinations of isotropic, anisotropic and restricted components, were tested. Models were ranked using the Akaike information criterion. In all four prostates, two-component models, comprising an anisotropic Gaussian component and an isotropic restricted component, ranked highest in the majority of voxels. Single-component models, whether isotropic (apparent diffusion coefficient, ADC) or anisotropic (diffusion tensor imaging, DTI), consistently ranked lower than multi-component models. Model ranking trends were independent of voxel size and maximum b value in the range tested (1.6-16 mm(3) and 3000-10,000 s/mm(2)). This study characterizes the two major water components previously identified by biexponential models and shows that models incorporating both anisotropic and restricted components provide more information-rich descriptions of DWI signals in prostate tissue than single- or multi-component anisotropic models and models that do not account for restricted diffusion.
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Affiliation(s)
- Sisi Liang
- College of Engineering and Science, Victoria University, Melbourne, Australia
| | | | - Andre Bongers
- Mark Wainright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Peng Shi
- College of Engineering and Science, Victoria University, Melbourne, Australia
| | - Paul Sved
- Department of Urology, Royal Prince Alfred Hospital, School of Medicine, University of Sydney, Sydney, Australia
| | - Geoffrey Watson
- Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Roger Bourne
- Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Sydney, Australia
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29
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Yeh FC, Liu L, Hitchens TK, Wu YL. Mapping immune cell infiltration using restricted diffusion MRI. Magn Reson Med 2016; 77:603-612. [PMID: 26843524 DOI: 10.1002/mrm.26143] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [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: 09/07/2015] [Revised: 01/04/2016] [Accepted: 01/05/2016] [Indexed: 12/15/2022]
Abstract
PURPOSE Diffusion MRI provides a noninvasive way to assess tissue microstructure. Based on diffusion MRI, we propose a model-free method called restricted diffusion imaging (RDI) to quantify restricted diffusion and correlate it with cellularity. THEORY AND METHODS An analytical relation between q-space signals and the density of restricted spins was derived to quantify restricted diffusion. A phantom study was conducted to investigate the performance of RDI, and RDI was applied to an animal study to assess immune cell infiltration in myocardial tissues with ischemia-reperfusion injury. RESULTS Our phantom study showed a correlation coefficient of 0.998 between cell density and the restricted diffusion quantified by RDI. The animal study also showed that the high-value regions in RDI matched well with the macrophage infiltration areas in the H&E stained slides. In comparison with diffusion tensor imaging (DTI), RDI exhibited its outperformance to detect macrophage infiltration and delineate inflammatory myocardium. CONCLUSION RDI can be used to reveal cell density and detect immune cell infiltration. RDI exhibits better specificity than the diffusivity measurement derived from DTI. Magn Reson Med 77:603-612, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Fang-Cheng Yeh
- Department of Psychology, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Li Liu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - T Kevin Hitchens
- Animal Imaging Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yijen L Wu
- Rangos Research Center Animal Imaging Core, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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30
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Paulsen JL, Özarslan E, Komlosh ME, Basser PJ, Song YQ. Detecting compartmental non-Gaussian diffusion with symmetrized double-PFG MRI. NMR Biomed 2015; 28:1550-1556. [PMID: 26434812 PMCID: PMC4618711 DOI: 10.1002/nbm.3363] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [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: 02/02/2015] [Revised: 05/14/2015] [Accepted: 06/15/2015] [Indexed: 05/30/2023]
Abstract
Diffusion in tissue and porous media is known to be non-Gaussian and has been used for clinical indications of stroke and other tissue pathologies. However, when conventional NMR techniques are applied to biological tissues and other heterogeneous materials, the presence of multiple compartments (pores) with different Gaussian diffusivities will also contribute to the measurement of non-Gaussian behavior. Here we present symmetrized double PFG (sd-PFG), which can separate these two contributions to non-Gaussian signal decay as having distinct angular modulation frequencies. In contrast to prior angular d-PFG methods, sd-PFG can unambiguously extract kurtosis as an oscillation from samples with isotropic or uniformly oriented anisotropic pores, and can generally extract a combination of compartmental anisotropy and kurtosis. The method further fixes its sensitivity with respect to the time dependence of the apparent diffusion coefficient. We experimentally demonstrate the measurement of the fourth cumulant (kurtosis) of diffusion and find it consistent with theoretical predictions. By enabling the unambiguous identification of contributions of compartmental kurtosis to the signal, sd-PFG has the potential to help identify the underlying micro-structural changes corresponding to current kurtosis based diagnostics, and act as a novel source of contrast to better resolve tissue micro-structure.
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Affiliation(s)
| | - Evren Özarslan
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02215, USA
- Section on Tissue Biophysics and Biomimetics, PPITS, NICHD, National Institutes of Health, Bethesda, MD, 20892, USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
- Department of Physics, Boğaziçi University, Bebek, 34342, İstanbul, Turkey
| | - Michal E Komlosh
- Section on Tissue Biophysics and Biomimetics, PPITS, NICHD, National Institutes of Health, Bethesda, MD, 20892, USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Peter J Basser
- Section on Tissue Biophysics and Biomimetics, PPITS, NICHD, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yi-Qiao Song
- Schlumberger-Doll Research, Cambridge, MA, 02139, USA
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31
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Abstract
Dopamine is an important neurotransmitter that exhibits numerous functions in the healthy, injured, and diseased brain. Fast scan cyclic voltammetry paired with electrical stimulation of dopamine axons is a popular and powerful method for investigating the dynamics of dopamine in the extracellular space. Evidence now suggests that the heterogeneity of electrically evoked dopamine responses reflects the inherent kinetic diversity of dopamine systems, which might contribute to their diversity of physiological function. Dopamine measurements by fast scan cyclic voltammetry are affected by the adsorption of dopamine to carbon fiber electrodes. The temporal distortion caused by dopamine adsorption is correctable by a straightforward mathematical procedure. The corrected responses exhibit excellent agreement with a dopamine kinetic model cast to provide a generic description of restricted diffusion, short-term plasticity of dopamine release, and first-order dopamine clearance. The new DA kinetic model brings to light the rich kinetic information content of electrically evoked dopamine responses recorded via fast scan cyclic voltammetry in the rat dorsal striatum.
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Affiliation(s)
- Seth H. Walters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Elaine M. Robbins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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32
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Hesselink JR, Barkovich MJ, Seibert TM, Farid N, Muller KA, Murphy KT, Kesari S. Bevacizumab: radiation combination produces restricted diffusion on brain MRI. CNS Oncol 2015; 3:329-35. [PMID: 25363005 DOI: 10.2217/cns.14.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 11/21/2022] Open
Abstract
AIMS The purpose of this paper is to investigate the effect of bevacizumab (BEV) on the diffusion properties of irradiated brain gliomas. MATERIALS & METHODS Neuroimaging studies and medical records of 44 patients undergoing treatment for cerebral gliomas were reviewed. MRIs were analyzed for presence of restricted diffusion, time to onset, pattern/location, duration of restriction, and persistence of restriction post-treatment with BEV. RESULTS Patchy confluent areas of diffusion restriction on MRI were found in 12 patients. All 12 patients received radiation therapy followed by BEV therapy. Diffusion restriction appeared 3 to 21 months after onset of radiation and 1 to 6 months after starting BEV therapy, increased in size over time, and persisted up to 23 months while on BEV. Restricted diffusion was observed in areas that received 60 Gy or more of radiation. Areas of restricted diffusion showed low T1 and increased T2 signal intensity, minimal or no contrast enhancement, and low cerebral blood volume. A thin perimeter of susceptibility outlined the restricted areas on susceptibility-weighted images in nine patients (75%). Small focal areas of tumor recurrence within larger regions of restricted diffusion were evident in only four patients (33%). In seven patients (58%) the area of restricted diffusion showed necrosis or radiation change on histology or no metabolic activity on MR spectroscopy or PET. CONCLUSION Restricted diffusion associated with BEV-treated cerebral gliomas occurs in regions of high-dose radiation and does not indicate high-cellularity of tumor recurrence.
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Affiliation(s)
- John R Hesselink
- Department of Radiology, UCSD Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8749, USA
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33
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Dunn DP, Lee KS, Smith MP, Mortele KJ. Nononcologic applications of diffusion-weighted imaging in the gastrointestinal system. AJR Am J Roentgenol 2015; 204:758-67. [PMID: 25794064 DOI: 10.2214/AJR.14.12729] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The purpose of this article is to review infectious, inflammatory, and auto-immune-mediated processes in the gastrointestinal system where diffusion-weighted imaging can be helpful as well as pitfalls associated with its use. CONCLUSION Diffusion-weighted imaging has become an important and widely used tool in abdominal and pelvic MRI, but it has been used primarily for oncologic applications. As more body MRI protocols are routinely including diffusion-weighted imaging, this sequence can be useful in evaluating an increasing number of nononcologic processes.
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34
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Manning AP, Giese M, Terpstra AS, MacLachlan MJ, Hamad WY, Dong RY, Michal CA. NMR of guest-host systems: 8CB in chiral nematic porous glasses. Magn Reson Chem 2014; 52:532-539. [PMID: 25251221 DOI: 10.1002/mrc.4101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/26/2014] [Accepted: 06/06/2014] [Indexed: 06/03/2023]
Abstract
Liquid crystals confined to porous materials often have different critical phenomena and ordering than in the bulk. Through the selection of pore size, structure and guest liquid crystal, these systems could enable a variety of functional materials for applications such as sensors and displays. A recent example of such a system is chiral nematic mesoporous films infiltrated with liquid crystal 4-cyano-4'-n-octylbiphenyl (8CB), which has reversible thermal switching of its optical bandgap. The optical bandgap is lost when the ordered 8CB guests are heated above ∼50 °C, where the 8CB becomes isotropic. In this study, we have used NMR cryoporometry and pulsed-field gradient diffusion measurements to determine the pore sizes and structures of various chiral nematic mesoporous silica and organosilica films. Temperature and orientation-dependent wideline (15)N NMR spectra of films infiltrated with (15)N-labelled 8CB guests show that the ordering of the 8CB mesogens is consistent with an average orientation parallel to the chiral nematic pore axes. Inclusion of a large, orientation-dependent shift was necessary to fit the spectra, probably due to susceptibility differences between the 8CB guests and the organosilica host.
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Affiliation(s)
- Alan P Manning
- Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada
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35
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Abstract
In vivo fast-scan cyclic voltammetry provides high-fidelity recordings of electrically evoked dopamine release in the rat striatum. The evoked responses are suitable targets for numerical modeling because the frequency and duration of the stimulus are exactly known. Responses recorded in the dorsal and ventral striatum of the rat do not bear out the predictions of a numerical model that assumes the presence of a diffusion gap interposed between the recording electrode and nearby dopamine terminals. Recent findings, however, suggest that dopamine may be subject to restricted diffusion processes in brain extracellular space. A numerical model cast to account for restricted diffusion produces excellent agreement between simulated and observed responses recorded under a broad range of anatomical, stimulus, and pharmacological conditions. The numerical model requires four, and in some cases only three, adjustable parameters and produces meaningful kinetic parameter values.
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Affiliation(s)
- Seth H. Walters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - I. Mitch Taylor
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Zhan Shu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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36
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Tan LA, Boco T, Johnson AK, Rivas FF, Ahmed S, Byrd SE, Byrne RW. Magnetic resonance imaging characteristics of typical and atypical/anaplastic meningiomas - Case series and literature review. Br J Neurosurg 2014; 29:77-81. [PMID: 25221967 DOI: 10.3109/02688697.2014.957647] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The histologic grades of meningiomas have a significant impact on the risk of recurrence, prognosis, and the need for adjuvant treatment such as radiation therapy. The purpose of this study is to investigate the magnetic resonance imaging (MRI) characteristics of typical and atypical/anaplastic meningiomas. METHODS The medical records of 32 consecutive patients who underwent meningioma resections between April 2004 and November 2006 were retrospectively reviewed. Preoperative MR studies were reviewed by board-certified neuroradiologists. Both univariate and multivariate analyses were used to analyze the MR characteristics of the typical and atypical/anaplastic meningiomas. A review of pertinent literature was also conducted. RESULTS Thirty-two patients were identified during the study period. Histopathologic examination of the surgical specimens revealed 27 (84.4% - Group I) typical meningiomas and 5 (15.6% - Group 2) atypical/anaplastic meningiomas. The chi-square test showed that restricted diffusion was much more likely to be present in Group 2 (p < 0.01), and the choline-to-creatinine (Cho/Cr) ratio was significantly higher in Group 2 (8.8 vs. 5.1, p = 0.01). The multivariate analysis confirmed that the atypical/anaplastic group is much more likely to have restricted diffusion (p = 0.02) and higher Cho/Cr ratios (p = 0.03). CONCLUSION Meningiomas with restricted diffusion and higher Cho/Cr ratio on MR spectroscopy are more likely to be atypical/anaplastic types. Preoperative MRI utilizing these sequences can provide important information which can be valuable to counsel patients regarding prognosis, risk of recurrence and the need for adjuvant radiation in addition to surgical resection.
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Affiliation(s)
- Lee A Tan
- a Departments of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Tibor Boco
- a Departments of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Andrew K Johnson
- a Departments of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Francisco F Rivas
- b Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center , Chicago , IL , USA
| | - Saud Ahmed
- c Rush Medical College , Chicago , IL , USA
| | - Sharon E Byrd
- b Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center , Chicago , IL , USA
| | - Richard W Byrne
- a Departments of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
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Ben-Yoav H, Dykstra PH, Gordonov T, Bentley WE, Ghodssi R. A microfluidic-based electrochemical biochip for label-free DNA hybridization analysis. J Vis Exp 2014:51797. [PMID: 25285529 PMCID: PMC4828060 DOI: 10.3791/51797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.
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Affiliation(s)
- Hadar Ben-Yoav
- MEMS Sensors and Actuators Laboratory (MSAL), Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland;
| | - Peter H Dykstra
- MEMS Sensors and Actuators Laboratory (MSAL), Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland
| | - Tanya Gordonov
- Institute for Bioscience and Biotechnology Research, Fischell Department of Bioengineering, University of Maryland
| | - William E Bentley
- Institute for Bioscience and Biotechnology Research, Fischell Department of Bioengineering, University of Maryland
| | - Reza Ghodssi
- MEMS Sensors and Actuators Laboratory (MSAL), Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland
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Lam WW, Jbabdi S, Miller KL. A model for extra-axonal diffusion spectra with frequency-dependent restriction. Magn Reson Med 2014; 73:2306-20. [PMID: 25046481 PMCID: PMC4682484 DOI: 10.1002/mrm.25363] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [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: 01/14/2014] [Revised: 06/24/2014] [Accepted: 06/24/2014] [Indexed: 11/09/2022]
Abstract
PURPOSE In the brain, there is growing interest in using the temporal diffusion spectrum to characterize axonal geometry in white matter because of the potential to be more sensitive to small pores compared to conventional time-dependent diffusion. However, analytical expressions for the diffusion spectrum of particles have only been derived for simple, restricting geometries such as cylinders, which are often used as a model for intra-axonal diffusion. The extra-axonal space is more complex, but the diffusion spectrum has largely not been modeled. We propose a model for the extra-axonal space, which can be used for interpretation of experimental data. THEORY AND METHODS An empirical model describing the extra-axonal space diffusion spectrum was compared with simulated spectra. Spectra were simulated using Monte Carlo methods for idealized, regularly and randomly packed axons over a wide range of packing densities and spatial scales. The model parameters are related to the microstructural properties of tortuosity, axonal radius, and separation for regularly packed axons and pore size for randomly packed axons. RESULTS Forward model predictions closely matched simulations. The model fitted the simulated spectra well and accurately estimated microstructural properties. CONCLUSIONS This simple model provides expressions that relate the diffusion spectrum to biologically relevant microstructural properties.
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Affiliation(s)
- Wilfred W Lam
- Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Saâd Jbabdi
- Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Karla L Miller
- Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
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White NS, Dale AM. Distinct effects of nuclear volume fraction and cell diameter on high b-value diffusion MRI contrast in tumors. Magn Reson Med 2013; 72:1435-43. [PMID: 24357182 DOI: 10.1002/mrm.25039] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [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: 06/25/2013] [Revised: 10/02/2013] [Accepted: 10/20/2013] [Indexed: 01/26/2023]
Abstract
PURPOSE While many recent studies have demonstrated improved detection and characterization of malignant lesions using high b-value diffusion imaging techniques, little is known about the underlying physical characteristics of tumor cells that modulate the restricted water signal at high b on clinical scanners. METHODS Monte Carlo simulations of diffusion in a synthetic tumor cell environment were used to study the specific effects of tumor cell diameter and nuclear volume fraction (ν) on high b diffusion contrast. RESULTS Results indicate that clinical pulsed-gradient spin-echo diffusion-weighted signals measured at high b (∼4000 s/mm(2)), long diffusion time (Δ ∼40-60 ms), and long echo time (TE ∼60-140 ms) are generally insensitive to tumor cell diameter, but increase exponentially with ν. Moreover, these results are predicted by a simple analytic expression for the intracellular restricted water signal with elevated T2 for the intranuclear versus cytosolic compartment. CONCLUSION Nuclear volume fraction is an important characteristic of cancer cells that modulates the apparent restriction of water at high b on clinical scanners. This model offers a possible explanation for the apparent unreliable correlation between tumor cell density (cellularity) and traditional ADC.
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Affiliation(s)
- Nathan S White
- Department of Radiology, University of California, San Diego, La Jolla, California, USA
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Abstract
Maple syrup urine disease is a rare inborn error of amino acid metabolism involving catabolic pathway of the branched-chain amino acids. This disease, if left untreated, may cause damage to the brain and may even cause death. These patients typically present with distinctive maple syrup odour of sweat and urine. Patients typically present with skin and urine smelling like maple syrup. Here we describe a case with relevant magnetic resonance imaging findings and confirmatory biochemical findings.
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Affiliation(s)
- Venkatraman Indiran
- Department of Radiodiagnosis, Sree Balaji Medical College and Hospital, Chennai, India
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Abstract
This article reviews a new concept in magnetic resonance as applied to cellular and biological systems. Diffusion weighted magnetic resonance imaging can be used to infer information about restriction sizes of samples being measured. The measurements rely on the apparent diffusion coefficient changing with diffusion times as measurements move from restricted to free diffusion regimes. Pulsed gradient spin echo (PGSE) measurements are limited in the ability to shorten diffusion times and thus are limited in restriction sizes which can be probed. Oscillating gradient spin echo (OGSE) measurements could provide shorter diffusion times so smaller restriction sizes could be probed.
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Affiliation(s)
- Melanie Martin
- Department of Physics, University of Winnipeg and Department of Radiology, University of Manitoba
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Van AT, Holdsworth SJ, Bammer R. In vivo investigation of restricted diffusion in the human brain with optimized oscillating diffusion gradient encoding. Magn Reson Med 2013; 71:83-94. [PMID: 23447055 DOI: 10.1002/mrm.24632] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [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: 08/27/2012] [Revised: 11/18/2012] [Accepted: 12/17/2012] [Indexed: 11/07/2022]
Abstract
PURPOSE Previous studies in phantoms and animals using animal MR systems have shown promising results in using oscillating gradient spin echo (OGSE) diffusion acquisition to depict microstructure information. The OGSE approach has also been shown to be a sensitive biomarker of tumor treatment response and white matter-related diseases. Translating these studies to a human MR scanner faces multiple challenges due to the much weaker gradient system. The goals of this study are to optimize the OGSE acquisition for a human MR system and investigate its applicability in the in vivo human brain. METHODS An analytical analysis of the OGSE modulation spectrum was provided. Based on this analysis and thorough simulation experiments, the OGSE acquisition was optimized in terms of diffusion waveform shape, waveform timing, and sequence timing-to achieve higher diffusion sensitivity and better sampling of the diffusion spectrum. RESULTS The trapezoid-cosine waveform was found to be the optimal OGSE waveform. At the three employed peak encoding frequencies of 18 Hz, 44 Hz, and 63 Hz, the waveform polarity for the least blurry sampling of the diffusion spectrum was 90+/180-, 90+/180+, and 90+/180+, respectively. For the highest diffusion-to-noise ratio at 63 Hz, the b-value was 200 s/mm(2) and the echo time was 116 ms. Using the optimized sequence, a frequency dependence of the measured apparent diffusion coefficients was observed in white matter-dominant regions such as the corpus callosum. CONCLUSION The obtained results demonstrate, for the first time, the potential of using an OGSE acquisition for investigating microstructure information on a human MR system.
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Affiliation(s)
- Anh T Van
- Center for Quantitative Neuroimaging, Department of Radiology, Stanford University, Stanford, California, USA
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Xing H, Lin F, Wu Q, Gong Q. Investigation of different boundary treatment methods in Monte-Carlo simulations of diffusion NMR. Magn Reson Med 2012; 70:1167-72. [PMID: 23169149 DOI: 10.1002/mrm.24551] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [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: 05/17/2012] [Revised: 09/30/2012] [Accepted: 10/16/2012] [Indexed: 02/05/2023]
Abstract
PURPOSE To enrich and develop more convenient and effective boundary treatment method in Monte-Carlo simulation of restricted diffusion nuclear magnetic resonance. METHODS The conventional approach used in treating boundary behaviors of restricted diffusion is the elastic boundary reflection. Because random walk is not dynamic process, other boundary treatments such as inelastic reflection are acceptable and probably simplify the programming of diffusion nuclear magnetic resonance simulation. The present study simulated the pulse gradient spin echo nuclear magnetic resonance by employing three boundary models, i.e., the elastic boundary reflection, the non-elastic boundary reflection, and the equal-step-length random leap. Their effects on precision, convergence, and calculation efficiency were investigated, as well as the effects of non-fixed boundary reflection step-length drawn from a Gaussian distribution in barrier-crossing steps. RESULTS The results show no obvious difference in convergences and precisions for different methods when the relative step-length is sufficiently small. Compared with the traditional approach, the required computation time of the latter two was reduced in some degree. CONCLUSION Boundary treatments based on inelastic reflection are a feasible choice in Monte-Carlo simulation of nuclear magnetic resonance, and in comparison with the conventional approach, it not only renders programming more convenience but also possibly lead to higher calculating efficiency.
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Affiliation(s)
- Haoyang Xing
- Huaxi MR Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, China; School of Physical Science and Technology, Sichuan University, Chengdu, Sichuan, China
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Stokes AM, Wilson JW, Warren WS. Characterization of restricted diffusion in uni- and multi-lamellar vesicles using short distance iMQCs. J Magn Reson 2012; 223:31-40. [PMID: 22975234 PMCID: PMC3594806 DOI: 10.1016/j.jmr.2012.07.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [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: 06/14/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 06/01/2023]
Abstract
Improved understanding of the entrapment, transport, and release of drugs and small molecules within vesicles is important for drug delivery. Most methods rely on contrast agents or probe molecules; here, we propose a new MRI method to detect signal from water spins with restricted diffusion. This method is based on intermolecular double quantum coherences (iDQCs), which can probe the restricted diffusion characteristics at well-defined and tunable microscopic distance scales. By using an exceedingly short (and previously inaccessible) distance, the iDQC signal arises only from restricted diffusion spins and thereby provides a mechanism to directly image vesicle entrapment, transport, and release. Using uni- and multi-lamellar liposomes and polymersomes, we show how the composition, lamellar structure, vesicle size, and concentration affects the iDQC signal between coupled water spins at very short separation distances. The iDQC signal correlates well with conventional diffusion MRI and a proposed biexponential (multicompartmental) diffusion model. Finally, the iDQC signal was used to monitor dynamic changes in the lamellar structure as temperature-sensitive liposomes released their contents. These short distance iDQCs can probe the amount and diffusion of water entrapped in vesicles, which may be useful to further understand vesicle properties in materials science and drug delivery applications.
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Affiliation(s)
- A M Stokes
- Department of Chemistry and Center for Molecular and Biomolecular Imaging, Duke University, Durham, NC 27708, USA
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Abstract
Peliosis is a rare benign disorder that is characterized by the presence of diffuse blood-filled cystic spaces and can occur in the liver, spleen, bone-marrow, and lungs. We present a 10-year-old boy with Fanconi anemia who presented with peliosis hepatis due to androgen treatment. Magnetic resonance (MR) imaging revealed multiple non-enhancing masses. Some of the lesions revealed fluid-fluid levels and extrahepatic extension on MR images. Diffusion-weighted (DW) imaging showed restricted diffusion. Fluid-fluid levels and extrahepatic extensions are unusual findings for hepatic peliotic lesions. In addition, DW imaging findings of peliosis hepatis have not been reported previously.
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Affiliation(s)
- Bilal Battal
- Sarikamis Military Hospital, Department of Radiology, Sarikamis, Kars, Turkey.
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Milne ML, Conradi MS. Multi-exponential signal decay from diffusion in a single compartment. J Magn Reson 2009; 197:87-90. [PMID: 19121965 PMCID: PMC2672418 DOI: 10.1016/j.jmr.2008.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [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: 09/22/2008] [Revised: 11/25/2008] [Accepted: 12/05/2008] [Indexed: 05/25/2023]
Abstract
Multi-exponential decays in diffusion experiments are typically fitted to sums of exponentially decaying components; often this is taken as evidence for spins in multiple distinct compartments. Here we examine the signal decay due to diffusion in a single cylinder, for short diffusion times (lightly restricted). The signals are well-modeled by a sum of two exponentials, despite the single compartment housing the spins. The results agree with a previous theoretical examination of the problem. The implication for biological systems is that multiple decay signal components may not correspond to multiple physical compartments.
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Affiliation(s)
- Michelle L Milne
- Department of Physics, Washington University, Compton Hall, Campus Box 1105, One Brookings Drive, Saint Louis, MO 63130, USA.
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Carl M, Wilson Miller G, Mugler JP, Rohrbaugh S, Tobias WA, Cates GD. Measurement of hyperpolarized gas diffusion at very short time scales. J Magn Reson 2007; 189:228-40. [PMID: 17936048 PMCID: PMC2194618 DOI: 10.1016/j.jmr.2007.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 03/31/2007] [Revised: 09/12/2007] [Accepted: 09/12/2007] [Indexed: 05/15/2023]
Abstract
We present a new pulse sequence for measuring very-short-time-scale restricted diffusion of hyperpolarized noble gases. The pulse sequence is based on concatenating a large number of bipolar diffusion-sensitizing gradients to increase the diffusion attenuation of the MR signal while maintaining a fundamentally short diffusion time. However, it differs in several respects from existing methods that use oscillating diffusion gradients for this purpose. First, a wait time is inserted between neighboring pairs of gradient pulses; second, consecutive pulse pairs may be applied along orthogonal axes; and finally, the diffusion-attenuated signal is not simply read out at the end of the gradient train but is periodically sampled during the wait times between neighboring pulse pairs. The first two features minimize systematic differences between the measured (apparent) diffusion coefficient and the actual time-dependent diffusivity, while the third feature optimizes the use of the available MR signal to improve the precision of the diffusivity measurement in the face of noise. The benefits of this technique are demonstrated using theoretical calculations, Monte-Carlo simulations of gas diffusion in simple geometries, and experimental phantom measurements in a glass sphere containing hyperpolarized (3)He gas. The advantages over the conventional single-bipolar approach were found to increase with decreasing diffusion time, and thus represent a significant step toward making accurate surface-to-volume measurements in the lung airspaces.
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Affiliation(s)
- Michael Carl
- Department of Physics, University of Virginia, Charlottesville, VA, USA
| | - G. Wilson Miller
- Center for In-Vivo Hyperpolarized Gas MR Imaging, Department of Radiology, University of Virginia, Charlottesville, VA, USA
- *Correspondence should be addressed to: G. Wilson Miller, Ph.D., Radiology Research, Box 801339, 409 Lane Rd., Room 1146, University of Virginia, Charlottesville, VA 22908, , Phone: 434-243-9216, Fax: 434-924-9435
| | - John P. Mugler
- Center for In-Vivo Hyperpolarized Gas MR Imaging, Department of Radiology, University of Virginia, Charlottesville, VA, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Scott Rohrbaugh
- Department of Physics, University of Virginia, Charlottesville, VA, USA
| | - William A. Tobias
- Department of Physics, University of Virginia, Charlottesville, VA, USA
| | - Gordon D. Cates
- Department of Physics, University of Virginia, Charlottesville, VA, USA
- Center for In-Vivo Hyperpolarized Gas MR Imaging, Department of Radiology, University of Virginia, Charlottesville, VA, USA
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