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Chen Y, Guo H, Dong P, Li Y, Zhang Z, Mao N, Chu T, Sun Z, Wang F, Feng Z, Wang H, Ma H. Feasibility of 3.0 T balanced fast field echo non-contrast-enhanced whole-heart coronary magnetic resonance angiography. Cardiovasc Diagn Ther 2023; 13:51-60. [PMID: 36864952 PMCID: PMC9971310 DOI: 10.21037/cdt-22-487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/02/2022] [Indexed: 01/01/2023]
Abstract
Background Coronary artery disease (CAD) is one of the most common diseases seriously harmful to human health caused by atherosclerosis. Besides coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA), coronary magnetic resonance angiography (CMRA) has become an alternative examination. The purpose of this study was to prospectively evaluate the feasibility of 3.0 T free-breathing whole-heart non-contrast-enhanced coronary magnetic resonance angiography (NCE-CMRA). Methods After Institutional Review Board approval, the NCE-CMRA data sets of 29 patients acquired successfully at 3.0 T were evaluated independently by two blinded readers for visualization and image quality of coronary arteries using the subjective quality grade. The acquisition times were recorded in the meantime. A part of the patients had undergone CCTA, we represented stenosis by scores and used the Kappa to evaluate the consistency between CCTA and NCE-CMRA. Results Six patients did not get diagnostic image quality because of severe artifacts. The image quality score assessed by both radiologists is 3.2±0.7, which means the NCE-CMRA can show the coronary arteries excellently. The main vessels of the coronary artery on NCE-CMRA images are considered reliably assessable. The acquisition time of NCE-CMRA, is 8.8±1.2 min. The Kappa of CCTA and NCE-CMRA on detecting stenosis is 0.842 (P<0.001). Conclusions The NCE-CMRA results in reliable image quality and visualization parameters of coronary arteries within a short scan time. The NCE-CMRA and CCTA have a good agreement for detecting stenosis.
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Affiliation(s)
- Yang Chen
- Department of Medical Imaging, Weifang Medical University, Weifang, China
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Hao Guo
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Peng Dong
- Department of Medical Imaging, Weifang Medical University, Weifang, China
| | - Yue Li
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Zhongsheng Zhang
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Ning Mao
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Tongpeng Chu
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Zehua Sun
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Fang Wang
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Zhiqiang Feng
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Huaying Wang
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
| | - Heng Ma
- Department of Radiology, Qingdao University and Yantai Yuhuangding Hospital, Yantai, China
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Kim MJ, Hwang BY, Mampre D, Negoita S, Tsehay Y, Sair HI, Kang JY, Anderson WS. Apparent diffusion coefficient of piriform cortex and seizure outcome in mesial temporal lobe epilepsy after MR-guided laser interstitial thermal therapy: a single-institution experience. J Neurosurg 2022; 137:1601-1609. [PMID: 35535837 DOI: 10.3171/2022.3.jns212490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 03/08/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Piriform cortex (PC) is one of the critical structures in the epileptogenesis of mesial temporal lobe epilepsy (mTLE), but its role is poorly understood. The authors examined the utility of apparent diffusion coefficient (ADC; an MR-based marker of tissue pathology) of the PC as a predictor of seizure outcome in patients with mTLE undergoing MR-guided laser interstitial thermal therapy (MRgLITT). METHODS A total of 33 patients diagnosed with mTLE who underwent MRgLITT at the authors' institution were included in the study. The 6-month postoperative seizure outcomes were classified using the International League Against Epilepsy (ILAE) system as good (complete seizure freedom, ILAE class I) and poor (seizure present, ILAE classes II-VI). The PC and ablation volumes were manually segmented from both the preoperative and intraoperative MRI sequences, respectively. The mean ADC intensities of 1) preablation PC; 2) total ablation volume; 3) ablated portion of PC; and 4) postablation residual PC were calculated and compared between good and poor outcome groups. Additionally, the preoperative PC volumes and proportion of PC volume ablated were examined and compared between the subjects in the two outcome groups. RESULTS The mean age at surgery was 36.5 ± 3.0 years, and the mean follow-up duration was 1.9 ± 0.2 years. Thirteen patients (39.4%) had a good outcome. The proportion of PC ablated was significantly associated with seizure outcome (10.16 vs 3.30, p < 0.05). After accounting for the variability in diffusion tensor imaging acquisition parameters, patients with good outcome had a significantly higher mean ADC of the preablation PC (0.3770 vs -0.0108, p < 0.05) and the postoperative residual PC (0.4197 vs 0.0309, p < 0.05) regions compared to those with poor outcomes. No significant differences in ADC of the ablated portion of PC were observed (0.2758 vs -0.4628, p = 0.12) after performing multivariate analysis. CONCLUSIONS A higher proportion of PC ablated was associated with complete seizure freedom. Preoperative and postoperative residual ADC measures of PC were significantly higher in the good seizure outcome group in patients with mTLE who underwent MRgLITT, suggesting that ADC analysis can assist with postablation outcome prediction and patient stratification.
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Affiliation(s)
- Min Jae Kim
- 1Department of Neurosurgery, Johns Hopkins School of Medicine.,2Department of Neurology, Johns Hopkins School of Medicine.,3Department of Biomedical Engineering, Johns Hopkins School of Medicine; and
| | - Brian Y Hwang
- 1Department of Neurosurgery, Johns Hopkins School of Medicine
| | - David Mampre
- 1Department of Neurosurgery, Johns Hopkins School of Medicine
| | - Serban Negoita
- 1Department of Neurosurgery, Johns Hopkins School of Medicine
| | - Yohannes Tsehay
- 1Department of Neurosurgery, Johns Hopkins School of Medicine
| | - Haris I Sair
- 4Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Joon Y Kang
- 2Department of Neurology, Johns Hopkins School of Medicine
| | - William S Anderson
- 1Department of Neurosurgery, Johns Hopkins School of Medicine.,3Department of Biomedical Engineering, Johns Hopkins School of Medicine; and
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Park SY, Koh SH, Lee IJ, Lee K, Lee Y. Determination of optimum pixel size and slice thickness for tractography and ulnar nerve diffusion tensor imaging at the cubital tunnel using 3T MRI. Acta Radiol 2021; 62:1063-1071. [PMID: 32854528 DOI: 10.1177/0284185120951965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Small peripheral nerve tractography is challenging because of the trade-off among resolution, image acquisition time, and signal-to-noise ratio. PURPOSE To optimize pixel size and slice thickness parameters for fiber tractography and diffusion tensor imaging (DTI) of the ulnar nerve at the cubital tunnel using 3T magnetic resonance imaging (MRI). MATERIAL AND METHODS Fifteen healthy volunteers (mean age 30 ± 6.8 years) were recruited prospectively. Axial T2-weighted and DTI scans were acquired, covering the cubital tunnel, using different pixel sizes and slice thicknesses. Three-dimensional (3D) nerve tractography was evaluated for the median number and length of the reconstructed fiber tracts and visual score from 0 to 5. Two-dimensional (2D) cross-sectional DTI was evaluated for fractional anisotropy (FA) values throughout the length of the ulnar nerve. RESULTS A pixel size of 1.3 mm2 revealed the highest number of reconstructed nerve fibers compared to that of 1.1 mm2 (P = 0.048), with a good visual score. A slice thickness of 4 mm had the highest number of reconstructed nerve fibers and visual score compared with other thicknesses (all P < 0.05). In 2D cross-sectional images, the median FA values were in the range of 0.40-0.63 at the proximal, central, and distal portions of the cubital tunnel. Inter-observer agreement for all parameters was good to excellent. CONCLUSION For fiber tractography and DTI of the ulnar nerve at the cubital tunnel, optimal image quality was obtained using a 1.3-mm2 pixel size and 4-mm slice thickness under MR parameters of this study at 3T.
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Affiliation(s)
- Sun-Young Park
- Department of Radiology, Hallym University Sacred Heart Hospital, Gyeonggi-do, Republic of Korea
| | - Sung Hye Koh
- Department of Radiology, Hallym University Sacred Heart Hospital, Gyeonggi-do, Republic of Korea
| | - In Jae Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Gyeonggi-do, Republic of Korea
| | - Kwanseop Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Gyeonggi-do, Republic of Korea
| | - Yul Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Gyeonggi-do, Republic of Korea
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Kim MJ, Hwang B, Mampre D, Negoita S, Tsehay Y, Sair H, Kang JY, Anderson W. Apparent diffusion coefficient is associated with seizure outcome after magnetic resonance-guided laser interstitial thermal therapy for mesial temporal lobe epilepsy. Epilepsy Res 2021; 176:106726. [PMID: 34298428 DOI: 10.1016/j.eplepsyres.2021.106726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) is becoming a first-line surgical therapy for mesial temporal lobe epilepsy (mTLE) due to good seizure control and low complication risk. However, seizure outcomes after MRgLiTT remain highly variable and there is a need to improve patient selection and post-operative prognostication. In this retrospective study, we investigated whether the pre-operative MRI-derived apparent diffusion coefficient (ADC), used as a marker of tissue pathology in the mesial temporal structures could help predict seizure outcome. METHODS Thirty-five patients who underwent MRgLiTT at our institution between 2014 and 2019 were included in the study. Demographic and clinical data were retrospectively collected. Seizure outcome was defined as good (ILAE Class I-II) and poor (ILAE Class III-VI). Volumetrics were performed on pre-ablation hippocampus and amygdala. Ablation volumes, and the proportion of ablated hippocampus and amygdala calculated via their respective mean voxel-wise ADC intensities were quantified from pre-operative and intra-operative post-ablation MRIs and statistically compared between the two outcome cohorts. Univarate and multivariate regression analysis was performed to identify demographic, clinical, and radiographic predictors of seizure outcome. RESULTS Mean age at LiTT was 36 years and 14 (40 %) were female. Mean follow-up duration was 1.90 ± 0.17 years. Twenty-seven (77 %) patients had mesial temporal sclerosis. There was no significant difference in the ablation volumes and proportion of ablated volume of hippocampus and amygdala between the two outcome groups. Patients with good seizure outcome had significantly higher normalized ADC intensities in the ablated mesial temporal structures compared to those with poor outcome (0.01 ± 0.08 vs.-0.29 ± 0.06; p = 0.015). CONCLUSIONS mTLE patients with higher ADC intensities in the ablated regions of the hippocampus and the amygdala are more likely to have good seizure outcome following MRgLiTT. Our results suggest that pre-operative ADC analysis may improve both patient selection and epileptogenic zone targeting during MRgLiTT. Further investigation with large, prospective cohorts is needed to validate the clinical utility of ADC in improving seizure outcome following MRgLiTT.
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Affiliation(s)
- Min Jae Kim
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - Brian Hwang
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - David Mampre
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - Serban Negoita
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - Yohannes Tsehay
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - Haris Sair
- Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - Joon Y Kang
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
| | - William Anderson
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, 21205, United States.
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The reproducibility of measurements using a standardization phantom for the evaluation of fractional anisotropy (FA) derived from diffusion tensor imaging (DTI). MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 33:293-298. [PMID: 31552552 DOI: 10.1007/s10334-019-00776-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/19/2019] [Accepted: 09/06/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES It is necessary to standardize the examination procedure and diagnostic criteria of diffusion tensor imaging (DTI). Thus, the purpose of this study was to examine the reproducibility of measurements using a standardization phantom composed of different fibre materials with different fibre densities (FDs) for the evaluation of fractional anisotropy (FA) derived from DTI. MATERIALS AND METHODS Two types of fibre materials wrapped in heat-shrinkable tubes were used as fibre phantoms. We designed fibre phantoms with three different FDs of each fibre material. The standardization phantom was examined using DTI protocol six times a day, and each examination session was repeated once a month for 7 consecutive months. Fibre tracking was performed by setting regions of interest in the FA map, and FA was measured in each fibre phantom. Coefficients of variation (CVs) were used to evaluate the inter-examination reproducibility of FA values. Furthermore, Bland-Altman plots were used to evaluate the intra-operator reproducibility of FA measurements. RESULTS All CVs for each fibre phantom were within 2% throughout the 7-month study of repeated DTI sessions. The high intra-operator reproducibility of the FA measurement was confirmed. DISCUSSION High reproducibility of measurements using a standardization phantom for the evaluation of FA was achieved.
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Suzuki M, Moriya S, Hata J, Tachibana A, Senoo A, Niitsu M. Development of anisotropic phantoms using wood and fiber materials for diffusion tensor imaging and diffusion kurtosis imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 32:539-547. [PMID: 31144164 PMCID: PMC6764935 DOI: 10.1007/s10334-019-00761-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/12/2019] [Accepted: 05/23/2019] [Indexed: 11/30/2022]
Abstract
Objective Several studies have demonstrated that anisotropic phantoms can be utilized for diffusion magnetic resonance imaging. The purpose of our study was to examine whether wood is suitable as an anisotropic phantom material from the viewpoints of affordability and availability. In the current study, wood was used for restricted diffusion, and fibers were used for hindered diffusion. Materials and methods Wood and fiber phantoms were made. Diffusion kurtosis images were acquired with three magnetic resonance scanners. Fractional anisotropy, radial diffusivity, axial diffusivity, radial kurtosis and axial kurtosis values were measured. The wood phantom was imaged, and its durability was confirmed. The phantoms were imaged in varying orientations within the magnetic field. The wood was observed using an optical microscope. Results Ten kinds of wood and the fiber had a diffusion metrics. The wood diffusion metrics suggested low variation over a period of 9 months. Changing the orientation of the phantoms within the magnetic field resulted in changes in diffusion metrics. Observation of wood vessels and fibers was conducted. Discussion Wood and fibers have anisotropy and are promising as phantom materials. The development of anisotropic phantoms that anyone can use is useful for diffusion magnetic resonance imaging research and clinical applications.
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Affiliation(s)
- Masashi Suzuki
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-Ogu, Arakawa-ku, Tokyo, 116-8551, Japan.,Department of Radiology, Saitama Medical University Hospital, 38 Morohongo, Moroyama, Iruma, Saitama, 350-0495, Japan
| | - Susumu Moriya
- Sawai Memorial Breast Clinic, 98 Kamikamo-Matsumoto-cho, Kitaku-ku, Kyoto-shi, Kyoto, 603-8052, Japan
| | - Junichi Hata
- Laboratory for Marmoset Neural Architecture, Center for Brain Science RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Atsushi Tachibana
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Atsushi Senoo
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-Ogu, Arakawa-ku, Tokyo, 116-8551, Japan.
| | - Mamoru Niitsu
- Department of Radiology, Saitama Medical University Hospital, 38 Morohongo, Moroyama, Iruma, Saitama, 350-0495, Japan
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de Souza EM, Costa ET, Castellano G. Investigation of anisotropic fishing line-based phantom as tool in quality control of diffusion tensor imaging. Radiol Phys Technol 2019; 12:161-171. [PMID: 30877555 DOI: 10.1007/s12194-019-00507-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 12/14/2022]
Abstract
This work proposes a low-cost, fishing line-based phantom for quality control of diffusion tensor imaging (DTI). The device was applied to investigate the relationship between DTI indexes (DTIi) and imaging acquisition parameters. A Dyneema® fishing line phantom was built with fiber bundles of different thicknesses. DTI acquisitions were performed in a 3T magnetic resonance imaging scanner using an 8-channel and a 32-channel head coil. For each coil, the following acquisition parameters were changed, one at a time: diffusion sensitivity factor (b value), echo time, sensitivity encoding, voxel size, number of signal averages, and number of diffusion gradient directions (NDGD). DTIi including fractional anisotropy, relative anisotropy (RA), linear anisotropy (CL), and planar anisotropy (CP) were calculated for each image; the data were analyzed using the coefficient of variation (CV) and distributions of DTIi values. The 32-channel head coil presented higher CV values for the DTIi RA, CL, and CP when voxel size was changed. Using the phantom, dependences between diffusion-related parameters (b value and NDGD) and DTIi were also observed; the majority of these were for the smaller thickness fiber bundles. The device proved to be useful for the verification of the DTI performance over time.
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Affiliation(s)
- Edna Marina de Souza
- Biomedical Engineering Center, University of Campinas (UNICAMP), 163 Alexander Fleming St, Cidade Universitária, Campinas, SP, 13083 881, Brazil. .,Biomedical Engineering Department, School of Electrical and Computer Engineering, University of Campinas (UNICAMP), Campinas, Brazil. .,Neurophysics Group, Gleb Wataghin Physics Institute, University of Campinas (UNICAMP), 777 Sergio Buarque de Holanda St, University City, Campinas, SP, 13083 859, Brazil. .,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, Brazil.
| | - Eduardo Tavares Costa
- Biomedical Engineering Center, University of Campinas (UNICAMP), 163 Alexander Fleming St, Cidade Universitária, Campinas, SP, 13083 881, Brazil.,Biomedical Engineering Department, School of Electrical and Computer Engineering, University of Campinas (UNICAMP), Campinas, Brazil
| | - Gabriela Castellano
- Neurophysics Group, Gleb Wataghin Physics Institute, University of Campinas (UNICAMP), 777 Sergio Buarque de Holanda St, University City, Campinas, SP, 13083 859, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, Brazil
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Choe YH. A Glimpse on Trends and Characteristics of Recent Articles Published in the Korean Journal of Radiology. Korean J Radiol 2019; 20:1555-1561. [PMID: 31854145 PMCID: PMC6923209 DOI: 10.3348/kjr.2019.0928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yeon Hyeon Choe
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Jelescu IO, Budde MD. Design and validation of diffusion MRI models of white matter. FRONTIERS IN PHYSICS 2017; 28:61. [PMID: 29755979 PMCID: PMC5947881 DOI: 10.3389/fphy.2017.00061] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Diffusion MRI is arguably the method of choice for characterizing white matter microstructure in vivo. Over the typical duration of diffusion encoding, the displacement of water molecules is conveniently on a length scale similar to that of the underlying cellular structures. Moreover, water molecules in white matter are largely compartmentalized which enables biologically-inspired compartmental diffusion models to characterize and quantify the true biological microstructure. A plethora of white matter models have been proposed. However, overparameterization and mathematical fitting complications encourage the introduction of simplifying assumptions that vary between different approaches. These choices impact the quantitative estimation of model parameters with potential detriments to their biological accuracy and promised specificity. First, we review biophysical white matter models in use and recapitulate their underlying assumptions and realms of applicability. Second, we present up-to-date efforts to validate parameters estimated from biophysical models. Simulations and dedicated phantoms are useful in assessing the performance of models when the ground truth is known. However, the biggest challenge remains the validation of the "biological accuracy" of estimated parameters. Complementary techniques such as microscopy of fixed tissue specimens have facilitated direct comparisons of estimates of white matter fiber orientation and densities. However, validation of compartmental diffusivities remains challenging, and complementary MRI-based techniques such as alternative diffusion encodings, compartment-specific contrast agents and metabolites have been used to validate diffusion models. Finally, white matter injury and disease pose additional challenges to modeling, which are also discussed. This review aims to provide an overview of the current state of models and their validation and to stimulate further research in the field to solve the remaining open questions and converge towards consensus.
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Affiliation(s)
- Ileana O Jelescu
- Centre d'Imagerie Biomédicale, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matthew D Budde
- Zablocki VA Medical Center, Dept. of Neurosurgery, Medical College Wisconsin, Milwaukee, WI, USA
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The relationship between fractional anisotropy value and tumor microarchitecture in late-stage rat glioma. ASIAN PAC J TROP MED 2017; 10:607-611. [DOI: 10.1016/j.apjtm.2017.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/17/2017] [Accepted: 05/18/2017] [Indexed: 11/19/2022] Open
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11
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Souza EMD, Costa ET, Castellano G. Phantoms for diffusion-weighted imaging and diffusion tensor imaging quality control: a review and new perspectives. ACTA ACUST UNITED AC 2017. [DOI: 10.1590/2446-4740.07816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | - Gabriela Castellano
- University of Campinas, Brazil; Brazilian Institute of Neuroscience and Neurotechnology, Brazil
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Pullens P, Bladt P, Sijbers J, Maas AIR, Parizel PM. Technical Note: A safe, cheap, and easy-to-use isotropic diffusion MRI phantom for clinical and multicenter studies. Med Phys 2017; 44:1063-1070. [PMID: 28079257 DOI: 10.1002/mp.12101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/10/2016] [Accepted: 12/27/2016] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Since Diffusion Weighted Imaging (DWI) data acquisition and processing are not standardized, substantial differences in DWI derived measures such as Apparent Diffusion Coefficient (ADC) may arise which are related to the acquisition or MRI processing method, but not to the sample under study. Quality assurance using a standardized test object, or phantom, is a key factor in standardizing DWI across scanners. METHODS Current diffusion phantoms are either complex to use, not available in larger quantities, contain substances unwanted in a clinical environment, or are expensive. A diffusion phantom based on a polyvinylpyrrolidone (PVP) solution, together with a phantom holder, is presented and compared to existing diffusion phantoms for use in clinical DWI scans. An ADC vs. temperature calibration curve was obtained. RESULTS ADC of the phantom (808 to 857 ± 0.2 mm2 /s) is in the same range as ADC values found in brain tissue. ADC measurements are highly reproducible across time with an intra-class correlation coefficient of > 0.8. ADC as function of temperature (in Kelvin) can be estimated as ADCm(T)=[exp(-7.09)·exp-2903.81T-1293.55] with a total uncertainty (95% confidence limit) of ± 1.7%. CONCLUSION We present an isotropic diffusion MRI phantom, together with its temperature calibration curve, that is easy-to-use in a clinical environment, cost-effective, reproducible to produce, and that contains no harmful substances.
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Affiliation(s)
- Pim Pullens
- Department of Radiology, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium
| | - Piet Bladt
- iMinds - Vision Lab, Department of Physics, University of Antwerp, 2610, Antwerp, Belgium
| | - Jan Sijbers
- iMinds - Vision Lab, Department of Physics, University of Antwerp, 2610, Antwerp, Belgium
| | - Andrew I R Maas
- Department of Neurosurgery, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium
| | - Paul M Parizel
- Department of Radiology, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium
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Kuo DP, Lu CF, Liou M, Chen YC, Chung HW, Chen CY. Differentiation of the Infarct Core from Ischemic Penumbra within the First 4.5 Hours, Using Diffusion Tensor Imaging-Derived Metrics: A Rat Model. Korean J Radiol 2017; 18:269-278. [PMID: 28246507 PMCID: PMC5313515 DOI: 10.3348/kjr.2017.18.2.269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 09/02/2016] [Indexed: 12/21/2022] Open
Abstract
Objective To investigate whether the diffusion tensor imaging-derived metrics are capable of differentiating the ischemic penumbra (IP) from the infarct core (IC), and determining stroke onset within the first 4.5 hours. Materials and Methods All procedures were approved by the local animal care committee. Eight of the eleven rats having permanent middle cerebral artery occlusion were included for analyses. Using a 7 tesla magnetic resonance system, the relative cerebral blood flow and apparent diffusion coefficient maps were generated to define IP and IC, half hour after surgery and then every hour, up to 6.5 hours. Relative fractional anisotropy, pure anisotropy (rq) and diffusion magnitude (rL) maps were obtained. One-way analysis of variance, receiver operating characteristic curve and nonlinear regression analyses were performed. Results The evolutions of tensor metrics were different in ischemic regions (IC and IP) and topographic subtypes (cortical, subcortical gray matter, and white matter). The rL had a significant drop of 40% at 0.5 hour, and remained stagnant up to 6.5 hours. Significant differences (p < 0.05) in rL values were found between IP, IC, and normal tissue for all topographic subtypes. Optimal rL threshold in discriminating IP from IC was about -29%. The evolution of rq showed an exponential decrease in cortical IC, from -26.9% to -47.6%; an rq reduction smaller than 44.6% can be used to predict an acute stroke onset in less than 4.5 hours. Conclusion Diffusion tensor metrics may potentially help discriminate IP from IC and determine the acute stroke age within the therapeutic time window.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan.; Department of Radiology, Taoyuan Armed Forces General Hospital, Taoyuan 32551, Taiwan
| | - Chia-Feng Lu
- Research Center of Translational Imaging, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan.; Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei 112, Taiwan
| | - Michelle Liou
- Institute of Statistical Science, Academia Sinica, Taipei 11529, Taiwan
| | - Yung-Chieh Chen
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electrics and Bioinformatics, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Yu Chen
- Research Center of Translational Imaging, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Medical Imaging and Imaging Research Center, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, Tri-Service General Hospital, Taipei 114, Taiwan.; Department of Radiology, National Defense Medical Center, Taipei 114, Taiwan
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Park M, Moon WJ. Structural MR Imaging in the Diagnosis of Alzheimer's Disease and Other Neurodegenerative Dementia: Current Imaging Approach and Future Perspectives. Korean J Radiol 2016; 17:827-845. [PMID: 27833399 PMCID: PMC5102911 DOI: 10.3348/kjr.2016.17.6.827] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/26/2016] [Indexed: 11/29/2022] Open
Abstract
With the rise of aging population, clinical concern and research attention has shifted towards neuroimaging of dementia. The advent of 3T, magnetic resonance imaging (MRI) has permitted the anatomical imaging of neurodegenerative disease, specifically dementia, with improved resolution. Furthermore, more powerful techniques such as diffusion tensor imaging, quantitative susceptibility mapping, and magnetic transfer imaging have successfully emerged for the detection of micro-structural abnormalities. In the present review article, we provide a brief overview of Alzheimer's disease and explore recent neuroimaging developments in the field of dementia with an emphasis on structural MR imaging in order to propose a simple and easily applicable systematic approach to the imaging diagnosis of dementia.
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Affiliation(s)
- Mina Park
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul 05030, Korea
| | - Won-Jin Moon
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul 05030, Korea
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15
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Kim ES, Lee SK, Kwon MJ, Lee PH, Ju YS, Yoon DY, Kim HJ, Lee KS. Assessment of Blood-Brain Barrier Permeability by Dynamic Contrast-Enhanced MRI in Transient Middle Cerebral Artery Occlusion Model after Localized Brain Cooling in Rats. Korean J Radiol 2016; 17:715-24. [PMID: 27587960 PMCID: PMC5007398 DOI: 10.3348/kjr.2016.17.5.715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022] Open
Abstract
Objective The purpose of this study was to evaluate the effects of localized brain cooling on blood-brain barrier (BBB) permeability following transient middle cerebral artery occlusion (tMCAO) in rats, by using dynamic contrast-enhanced (DCE)-MRI. Materials and Methods Thirty rats were divided into 3 groups of 10 rats each: control group, localized cold-saline (20℃) infusion group, and localized warm-saline (37℃) infusion group. The left middle cerebral artery (MCA) was occluded for 1 hour in anesthetized rats, followed by 3 hours of reperfusion. In the localized saline infusion group, 6 mL of cold or warm saline was infused through the hollow filament for 10 minutes after MCA occlusion. DCE-MRI investigations were performed after 3 hours and 24 hours of reperfusion. Pharmacokinetic parameters of the extended Tofts-Kety model were calculated for each DCE-MRI. In addition, rotarod testing was performed before tMCAO, and on days 1-9 after tMCAO. Myeloperoxidase (MPO) immunohisto-chemistry was performed to identify infiltrating neutrophils associated with the inflammatory response in the rat brain. Results Permeability parameters showed no statistical significance between cold and warm saline infusion groups after 3-hour reperfusion 0.09 ± 0.01 min-1 vs. 0.07 ± 0.02 min-1, p = 0.661 for Ktrans; 0.30 ± 0.05 min-1 vs. 0.37 ± 0.11 min-1, p = 0.394 for kep, respectively. Behavioral testing revealed no significant difference among the three groups. However, the percentage of MPO-positive cells in the cold-saline group was significantly lower than those in the control and warm-saline groups (p < 0.05). Conclusion Localized brain cooling (20℃) does not confer a benefit to inhibit the increase in BBB permeability that follows transient cerebral ischemia and reperfusion in an animal model, as compared with localized warm-saline (37℃) infusion group.
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Affiliation(s)
- Eun Soo Kim
- Department of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068, Korea
| | - Seung-Koo Lee
- Department of Radiology, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Mi Jung Kwon
- Department of Pathology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068, Korea
| | - Phil Hye Lee
- Department of Neurology, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Young-Su Ju
- Department of Industrial Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068, Korea
| | - Dae Young Yoon
- Department of Radiology, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355, Korea
| | - Hye Jeong Kim
- Department of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul 07441, Korea
| | - Kwan Seop Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068, Korea
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Kim M, Kim HS. Emerging Techniques in Brain Tumor Imaging: What Radiologists Need to Know. Korean J Radiol 2016; 17:598-619. [PMID: 27587949 PMCID: PMC5007387 DOI: 10.3348/kjr.2016.17.5.598] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/03/2016] [Indexed: 12/11/2022] Open
Abstract
Among the currently available brain tumor imaging, advanced MR imaging techniques, such as diffusion-weighted MR imaging and perfusion MR imaging, have been used for solving diagnostic challenges associated with conventional imaging and for monitoring the brain tumor treatment response. Further development of advanced MR imaging techniques and postprocessing methods may contribute to predicting the treatment response to a specific therapeutic regimen, particularly using multi-modality and multiparametric imaging. Over the next few years, new imaging techniques, such as amide proton transfer imaging, will be studied regarding their potential use in quantitative brain tumor imaging. In this review, the pathophysiologic considerations and clinical validations of these promising techniques are discussed in the context of brain tumor characterization and treatment response.
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Affiliation(s)
- Minjae Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Korea
| | - Ho Sung Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Korea
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