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Tro' R, Roascio M, Arnulfo G, Tortora D, Severino M, Rossi A, Napolitano A, Fato MM. Influence of adaptive denoising on Diffusion Kurtosis Imaging at 3T and 7T. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 234:107508. [PMID: 37018885 DOI: 10.1016/j.cmpb.2023.107508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/24/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND AND OBJECTIVE Choosing the most appropriate denoising method to improve the quality of diagnostic images maximally is key in pre-processing of diffusion MRI images. Recent advancements in acquisition and reconstruction techniques have questioned traditional noise estimation methods favoring adaptive denoising frameworks, circumventing the need to know a priori information that is hardly available in a clinical setting. In this observational study, we compared two innovative adaptive techniques sharing some features, Patch2Self and Nlsam, through application on reference adult data at 3T and 7T. The primary aim was identifying the most effective method in case of Diffusion Kurtosis Imaging (DKI) data - particularly susceptible to noise and signal fluctuations - at 3T and 7T fields. A side goal consisted of investigating the dependence of kurtosis metrics' variability with respect to the magnetic field on the adopted denoising methodology. METHODS For comparison purposes, we focused on qualitative and quantitative analysis of DKI data and related microstructural maps before and after applying the two denoising approaches. Specifically, we assessed computational efficiency, preservation of anatomical details via perceptual metrics, consistency of microstructure model fitting, alleviation of degeneracies in model estimation, and joint variability with varying field strength and denoising method. RESULTS Accounting for all these factors, Patch2Self framework has turned out to be specifically suitable for DKI data, with improving performance at 7T. Nlsam method is more robust in alleviating degenerate black voxels while introducing some blurring, which in turn is reflected in an overall loss of image sharpness. Regarding the impact of denoising on field-dependent variability, both methods have been shown to make variations from standard to Ultra-High Field more concordant with theoretical evidence, claiming that kurtosis metrics are sensitive to susceptibility-induced background gradients, directly proportional to the magnetic field strength and sensitive to the microscopic distribution of iron and myelin. CONCLUSIONS This study serves as a proof-of-concept stressing the need for an accurate choice of a denoising methodology, specifically tailored for the data under analysis and allowing higher spatial resolution acquisition within clinically compatible timings, with all the potential benefits that improving suboptimal quality of diagnostic images entails.
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Affiliation(s)
- Rosella Tro'
- Department of Informatics, Bioengineering Robotics and System Engineering (DIBRIS), University of Genoa, Via all'Opera Pia, 13, Genoa 16145, Italy; RAISE Ecosystem, Genova, Italy.
| | - Monica Roascio
- Department of Informatics, Bioengineering Robotics and System Engineering (DIBRIS), University of Genoa, Via all'Opera Pia, 13, Genoa 16145, Italy; RAISE Ecosystem, Genova, Italy
| | - Gabriele Arnulfo
- Department of Informatics, Bioengineering Robotics and System Engineering (DIBRIS), University of Genoa, Via all'Opera Pia, 13, Genoa 16145, Italy; Neuroscience Center Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland; RAISE Ecosystem, Genova, Italy
| | - Domenico Tortora
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Andrea Rossi
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy
| | | | - Marco M Fato
- Department of Informatics, Bioengineering Robotics and System Engineering (DIBRIS), University of Genoa, Via all'Opera Pia, 13, Genoa 16145, Italy; RAISE Ecosystem, Genova, Italy
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Costantini G, Capuani S, Farrelly FA, Taloni A. Nuclear magnetic resonance signal decay in the presence of a background gradient: Normal and anomalous diffusion. J Chem Phys 2023; 158:2887937. [PMID: 37129963 DOI: 10.1063/5.0148175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/14/2023] [Indexed: 05/03/2023] Open
Abstract
A novel way for calculating the diffusion-weighted nuclear magnetic resonance (NMR) attenuation signal expression in the presence of a background gradient is developed. This method is easily applicable to NMR-attenuated signals arising from any pulse field gradient sequence experiments. Here, we provide detailed calculations for the classical pulsed gradient stimulated echo and the pulsed gradient spin echo, as the particular cases. Within this general theoretical framework, devised for Gaussian processes with stationary increments, we recover and extend the previous Stejskal-Tanner results in the case of normal diffusion and we furnish a new expression in the case of anomalous diffusion.
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Affiliation(s)
- G Costantini
- Istituto dei Sistemi Complessi-CNR, Sapienza, Piazzale A. Moro 2, I-00185 Rome, Italy
| | - S Capuani
- Istituto dei Sistemi Complessi-CNR, Sapienza, Piazzale A. Moro 2, I-00185 Rome, Italy
| | - F A Farrelly
- Istituto dei Sistemi Complessi-CNR, Via dei Taurini 19, I-00185 Rome, Italy
| | - A Taloni
- Istituto dei Sistemi Complessi-CNR, Via dei Taurini 19, I-00185 Rome, Italy
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Boonsuth R, Battiston M, Grussu F, Samlidou CM, Calvi A, Samson RS, Gandini Wheeler-Kingshott CAM, Yiannakas MC. Feasibility of in vivo multi-parametric quantitative magnetic resonance imaging of the healthy sciatic nerve with a unified signal readout protocol. Sci Rep 2023; 13:6565. [PMID: 37085693 PMCID: PMC10121559 DOI: 10.1038/s41598-023-33618-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/15/2023] [Indexed: 04/23/2023] Open
Abstract
Magnetic resonance neurography (MRN) has been used successfully over the years to investigate the peripheral nervous system (PNS) because it allows early detection and precise localisation of neural tissue damage. However, studies demonstrating the feasibility of combining MRN with multi-parametric quantitative magnetic resonance imaging (qMRI) methods, which provide more specific information related to nerve tissue composition and microstructural organisation, can be invaluable. The translation of emerging qMRI methods previously validated in the central nervous system to the PNS offers real potential to characterise in patients in vivo the underlying pathophysiological mechanisms involved in a plethora of conditions of the PNS. The aim of this study was to assess the feasibility of combining MRN with qMRI to measure diffusion, magnetisation transfer and relaxation properties of the healthy sciatic nerve in vivo using a unified signal readout protocol. The reproducibility of the multi-parametric qMRI protocol as well as normative qMRI measures in the healthy sciatic nerve are reported. The findings presented herein pave the way to the practical implementation of joint MRN-qMRI in future studies of pathological conditions affecting the PNS.
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Affiliation(s)
- Ratthaporn Boonsuth
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK.
- Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand.
| | - Marco Battiston
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Francesco Grussu
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Christina Maria Samlidou
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Alberto Calvi
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
- Laboratory of Advanced Imaging in Neuroimmunological Diseases, Center of Neuroimmunology, Hospital Clinic Barcelona, Fundació Clinic Per a La Recerca Biomedica, Barcelona, Spain
| | - Rebecca S Samson
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Claudia A M Gandini Wheeler-Kingshott
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
- Brain Connectivity Research Centre, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | - Marios C Yiannakas
- NMR Research Unit, Department of Neuroinflammation, Faculty of Brain Sciences, Queen Square MS Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
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Developing a Predictive Grading Model for Children with Gliomas Based on Diffusion Kurtosis Imaging Metrics: Accuracy and Clinical Correlations with Patient Survival. Cancers (Basel) 2022; 14:cancers14194778. [PMID: 36230701 PMCID: PMC9563289 DOI: 10.3390/cancers14194778] [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: 07/25/2022] [Revised: 09/19/2022] [Accepted: 09/24/2022] [Indexed: 11/20/2022] Open
Abstract
Purpose: To develop a predictive grading model based on diffusion kurtosis imaging (DKI) metrics in children affected by gliomas, and to investigate the clinical impact of the predictive model by correlating with overall survival and progression-free survival. Materials and methods: 59 patients with a histological diagnosis of glioma were retrospectively studied (33 M, 26 F, median age 7.2 years). Patients were studied on a 3T scanner with a standardized MR protocol, including conventional and DKI sequences. Mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) maps were obtained. Whole tumour volumes (VOIs) were segmented semi-automatically. Mean DKI values were calculated for each metric. The quantitative values from DKI-derived metrics were used to develop a predictive grading model to develop a probability prediction of a high-grade glioma (pHGG). Three models were tested: DTI-based, DKI-based, and combined (DTI and DKI). The grading accuracy of the resulting probabilities was tested with a receiver operating characteristics (ROC) analysis for each model. In order to account for dataset imbalances between pLGG and pHGG, we applied a random synthetic minority oversampling technique (SMOTE) analysis. Lastly, the most accurate model predictions were correlated with progression-free survival (PFS) and overall survival (OS) using the Kaplan−Meier method. Results: The cohort included 46 patients with pLGG and 13 patients with pHGG. The developed model predictions yielded an AUC of 0.859 (95%CI: 0.752−0.966) for the DTI model, of 0.939 (95%CI: 0.879−1) for the DKI model, and of 0.946 (95%CI: 0.890−1) for the combined model, including input from both DTI and DKI metrics, which resulted in the most accurate model. Sample estimation with the random SMOTE analysis yielded an AUC of 0.98 on the testing set. Model predictions from the combined model were significantly correlated with PFS (25.2 months for pHGG vs. 40.0 months for pLGG, p < 0.001) and OS (28.9 months for pHGG vs. 44.9 months for pLGG, p < 0.001). Conclusions: a DKI-based predictive model was highly accurate for pediatric glioma grading. The combined model, derived from both DTI and DKI metrics, proved that DKI-based model predictions of tumour grade were significantly correlated with progression-free survival and overall survival.
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Di Trani MG, Nezzo M, Caporale AS, De Feo R, Miano R, Mauriello A, Bove P, Manenti G, Capuani S. Performance of Diffusion Kurtosis Imaging Versus Diffusion Tensor Imaging in Discriminating Between Benign Tissue, Low and High Gleason Grade Prostate Cancer. Acad Radiol 2019; 26:1328-1337. [PMID: 30545680 DOI: 10.1016/j.acra.2018.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/25/2022]
Abstract
RATIONALE AND OBJECTIVES To investigate the performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in discriminating benign tissue, low- and high-grade prostate adenocarcinoma (PCa). MATERIALS AND METHODS Forty-eight patients with biopsy-proven PCa of different Gleason grade (GG), who provided written informed consent, were enrolled. All subjects underwent 3T DWI examinations by using b values 0, 500, 1000, 1500, 2000, and 2500 s/mm2 and six gradient directions. Mean diffusivity, fractional anisotropy (FA), apparent kurtosis (K), apparent kurtosis-derived diffusivity (D), and proxy fractional kurtosis anisotropy (KFA) maps were obtained. Regions of interest were selected in PCa, in the contralateral benign zone, and in the peritumoral area. Histogram analysis was performed by measuring mean, 10th, 25th, and 90th (p90) percentile of the whole-lesion volume. Kruskal-Wallis test with Bonferroni correction was used to assess significant differences between different regions of interest. The correlation between diffusion metrics and GG and between DKI and DTI parameters was evaluated with Pearson's test. ROC curve analysis was carried out to analyze the ability of histogram variables to differentiate low- and high-GG PCa. RESULTS All metrics significantly discriminated PCa from benign and from peritumoral tissue (except for K, KFAp90, and FA). Kp90 showed the highest correlation with GG and the best diagnostic ability (area under the curve = 0.84) in discriminating low- from high-risk PCa. CONCLUSION Compared to DTI, DKI provides complementary and additional information about prostate cancer tissue, resulting more sensitive to PCa-derived modifications and more accurate in discriminating low- and high-risk PCa.
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Affiliation(s)
- Maria Giovanna Di Trani
- Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy; Department of Anatomical, Histological, Forensic and Locomotor System Science, Sapienza University of Rome, Via A. Scarpa 16, Rome 00161, Italy.
| | - Marco Nezzo
- Department of Diagnostic and Interventional Radiology, Molecular Imaging and Radiotherapy, PTV Foundation, Tor Vergata University of Rome, Rome, Italy
| | - Alessandra S Caporale
- Department of Physics, CNR ISC, UOS Roma Sapienza, Sapienza University of Rome, Rome, Italy; Department of Radiology, University of Pennsylvania Hospital, Founders Pavilion, Philadelphia, Pennsylvania
| | - Riccardo De Feo
- Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy; Department of Physics, CNR ISC, UOS Roma Sapienza, Sapienza University of Rome, Rome, Italy
| | - Roberto Miano
- Urology Unit, Department of Experimental Medicine and Surgery, PTV Foundation, Tor Vergata University of Rome, Rome, Italy
| | - Alessandro Mauriello
- Anatomic Pathology, Department of Experimental Medicine and Surgery, PTV Foundation, Tor Vergata University of Rome, Rome, Italy
| | - Pierluigi Bove
- Urology Unit, Department of Experimental Medicine and Surgery, PTV Foundation, Tor Vergata University of Rome, Rome, Italy
| | - Guglielmo Manenti
- Department of Diagnostic and Interventional Radiology, Molecular Imaging and Radiotherapy, PTV Foundation, Tor Vergata University of Rome, Rome, Italy
| | - Silvia Capuani
- Department of Physics, CNR ISC, UOS Roma Sapienza, Sapienza University of Rome, Rome, Italy
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Guerreri M, Palombo M, Caporale A, Fasano F, Macaluso E, Bozzali M, Capuani S. Age-related microstructural and physiological changes in normal brain measured by MRI γ-metrics derived from anomalous diffusion signal representation. Neuroimage 2018; 188:654-667. [PMID: 30583064 DOI: 10.1016/j.neuroimage.2018.12.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/11/2018] [Accepted: 12/20/2018] [Indexed: 12/29/2022] Open
Abstract
Nowadays, increasing longevity associated with declining cerebral nervous system functions, suggests the need for continued development of new imaging contrast mechanisms to support the differential diagnosis of age-related decline. In our previous papers, we developed a new imaging contrast metrics derived from anomalous diffusion signal representation and obtained from diffusion-weighted (DW) data collected by varying diffusion gradient strengths. Recently, we highlighted that the new metrics, named γ-metrics, depended on the local inhomogeneity due to differences in magnetic susceptibility between tissues and diffusion compartments in young healthy subjects, thus providing information about myelin orientation and iron content within cerebral regions. The major structural modifications occurring in brain aging are myelinated fibers damage in nerve fibers and iron accumulation in gray matter nuclei. Therefore, we investigated the potential of γ-metrics in relation to other conventional diffusion metrics such as DTI, DKI and NODDI in detecting age-related structural changes in white matter (WM) and subcortical gray matter (scGM). DW-images were acquired in 32 healthy subjects, adults and elderly (age range 20-77 years) using 3.0T and 12 b-values up to 5000 s/mm2. Association between diffusion metrics and subjects' age was assessed using linear regression. A decline in mean γ (Mγ) in the scGM and a complementary increase in radial γ (γ⊥) in frontal WM, genu of corpus callosum and anterior corona radiata with advancing age were found. We suggested that the increase in γ⊥ might reflect declined myelin density, and Mγ decrease might mirror iron accumulation. An increase in D// and a decrease in the orientation dispersion index (ODI) were associated with axonal loss in the pyramidal tracts, while their inverted trends within the thalamus were thought to be linked to reduced architectural complexity of nerve fibers. γ-metrics together with conventional diffusion-metrics can more comprehensively characterize the complex mechanisms underlining age-related changes than conventional diffusion techniques alone.
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Affiliation(s)
- Michele Guerreri
- SAIMLAL Department, Sapienza, Piazzale Aldo Moro, 5, 00185, Roma, RM, Italy; Institute for Complex Systems, CNR, Rome, Italy.
| | - Marco Palombo
- Institute for Complex Systems, CNR, Rome, Italy; Department of Computer Science & Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Alessandra Caporale
- Institute for Complex Systems, CNR, Rome, Italy; Laboratory for Structural, Physiologic and Functional Imaging, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Marco Bozzali
- Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy
| | - Silvia Capuani
- Institute for Complex Systems, CNR, Rome, Italy; Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy
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Kunz N, da Silva AR, Jelescu IO. Intra- and extra-axonal axial diffusivities in the white matter: Which one is faster? Neuroimage 2018; 181:314-322. [PMID: 30005917 DOI: 10.1016/j.neuroimage.2018.07.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 06/29/2018] [Accepted: 07/09/2018] [Indexed: 10/28/2022] Open
Abstract
A two-compartment model of diffusion in white matter, which accounts for intra- and extra-axonal spaces, is associated with two plausible mathematical scenarios: either the intra-axonal axial diffusivity Da,‖ is higher than the extra-axonal De,‖ (Branch 1), or the opposite, i.e. Da,‖ < De,‖ (Branch 2). This duality calls for an independent validation of compartment axial diffusivities, to determine which of the two cases holds. The aim of the present study was to use an intracerebroventricular injection of a gadolinium-based contrast agent to selectively reduce the extracellular water signal in the rat brain, and compare diffusion metrics in the genu of the corpus callosum before and after gadolinium infusion. The diffusion metrics considered were diffusion and kurtosis tensor metrics, as well as compartment-specific estimates of the WMTI-Watson two-compartment model. A strong decrease in genu T1 and T2 relaxation times post-Gd was observed (p < 0.001), as well as an increase of 48% in radial kurtosis (p < 0.05), which implies that the relative fraction of extracellular water signal was selectively decreased. This was further supported by a significant increase in intra-axonal water fraction as estimated from the two-compartment model, for both branches (p < 0.01 for Branch 1, p < 0.05 for Branch 2). However, pre-Gd estimates of axon dispersion in Branch 1 agreed better with literature than those of Branch 2. Furthermore, comparison of post-Gd changes in diffusivity and dispersion between data and simulations further supported Branch 1 as the biologically plausible solution, i.e. Da,‖ > De,‖. This result is fully consistent with other recent measurements of compartment axial diffusivities that used entirely different approaches, such as diffusion tensor encoding.
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Affiliation(s)
- Nicolas Kunz
- Centre d'Imagerie Biomédicale, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Analina R da Silva
- Centre d'Imagerie Biomédicale, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ileana O Jelescu
- Centre d'Imagerie Biomédicale, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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Portakal ZG, Shermer S, Jenkins C, Spezi E, Perrett T, Tuncel N, Phillips J. Design and characterization of tissue-mimicking gel phantoms for diffusion kurtosis imaging. Med Phys 2018; 45:2476-2485. [PMID: 29635795 DOI: 10.1002/mp.12907] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 03/05/2018] [Accepted: 03/05/2018] [Indexed: 12/22/2022] Open
Abstract
PURPOSE The aim of this work was to create tissue-mimicking gel phantoms appropriate for diffusion kurtosis imaging (DKI) for quality assurance, protocol optimization, and sequence development. METHODS A range of agar, agarose, and polyvinyl alcohol phantoms with concentrations ranging from 1.0% to 3.5%, 0.5% to 3.0%, and 10% to 20%, respectively, and up to 3 g of glass microspheres per 100 ml were created. Diffusion coefficients, excess kurtosis values, and relaxation rates were experimentally determined. RESULTS The kurtosis values for the plain gels ranged from 0.05 with 95% confidence interval (CI) of (0.029,0.071) to 0.216(0.185,0.246), well below the kurtosis values reported in the literature for various tissues. The addition of glass microspheres increased the kurtosis of the gels with values up to 0.523(0.465,0.581) observed for gels with the highest concentration of microspheres. Repeat scans of some of the gels after more than 6 months of storage at room temperature indicate changes in the diffusion parameters of less than 10%. The addition of the glass microspheres reduces the apparent diffusion coefficients (ADCs) and increases the longitudinal and transverse relaxation rates, but the values remain comparable to those for plain gels and tissue, with ADCs observed ranging from 818(585,1053) × 10-6 mm2 /s to 2257(2118,2296) × 10-6 mm2 /s, R1 values ranging from 0.34(0.32,0.35) 1/s to 0.51(0.50,0.52) 1/s, and R2 values ranging from 9.69(9.34,10.04) 1/s to 33.07(27.10, 39.04) 1/s. CONCLUSIONS Glass microspheres can be used to effectively modify diffusion properties of gel phantoms and achieve a range of kurtosis values comparable to those reported for a variety of tissues.
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Affiliation(s)
- Ziyafer Gizem Portakal
- Department of Physics, Science and Arts Faculty, Cukurova University, 01330, Adana, Turkey.,Department of Medical Physics, Velindre Cancer Centre, CF14 2TL, Cardiff, UK
| | - Sophie Shermer
- Department of Physics, College of Science, Swansea University, SA2 8PP, Swansea, UK
| | - Christopher Jenkins
- Department of Physics, College of Science, Swansea University, SA2 8PP, Swansea, UK
| | - Emiliano Spezi
- Department of Medical Physics, Velindre Cancer Centre, CF14 2TL, Cardiff, UK.,School of Engineering, Cardiff University, CF24 3AA, Cardiff, UK
| | - Teresa Perrett
- Department of Medical Physics, Velindre Cancer Centre, CF14 2TL, Cardiff, UK
| | - Nina Tuncel
- Department of Physics, Science Faculty, Akdeniz University, 07058, Antalya, Turkey
| | - Jonathan Phillips
- Institute of Life Science, Medical School, Swansea University, Swansea, SA2 8PP, UK
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Chen Y, Sha M, Zhao X, Ma J, Ni H, Gao W, Ming D. Automated detection of pathologic white matter alterations in Alzheimer's disease using combined diffusivity and kurtosis method. Psychiatry Res Neuroimaging 2017; 264:35-45. [PMID: 28448817 DOI: 10.1016/j.pscychresns.2017.04.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 04/01/2017] [Accepted: 04/12/2017] [Indexed: 10/19/2022]
Abstract
Diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) are important diffusion MRI techniques for detecting microstructure abnormities in diseases such as Alzheimer's. The advantages of DKI over DTI have been reported generally; however, the indistinct relationship between diffusivity and kurtosis has not been clearly revealed in clinical settings. In this study, we hypothesize that the combination of diffusivity and kurtosis in DKI improves the capacity of DKI to detect Alzheimer's disease compared with diffusivity or kurtosis alone. Specifically, a support vector machine-based approach was applied to combine diffusivity and kurtosis and to compare different indices datasets. Strict assessments were conducted to ensure the reliability of all classifiers. Then, data from the optimized classifiers were used to detect abnormalities. With the combination, high accuracy performances of 96.23% were obtained in 53 subjects, including 27 Alzheimer's patients. More highly scored abnormal regions were selected by the combination than alone. The results revealed that more precise diffusivity and complementary kurtosis mainly contributed to the high performance of the combination in DKI. This study provides further understanding of DKI and the relationship between diffusivity and kurtosis in pathologic white matter alterations in Alzheimer's disease.
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Affiliation(s)
- Yuanyuan Chen
- School of Electronics and Information Engineering, Tianjin University, Tianjin, China.
| | - Miao Sha
- The Neural Engineering & Rehabilitation lab, Tianjin University, Tianjin, China.
| | - Xin Zhao
- The Neural Engineering & Rehabilitation lab, Tianjin University, Tianjin, China.
| | - Jianguo Ma
- School of Electronics and Information Engineering, Tianjin University, Tianjin, China.
| | - Hongyan Ni
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China.
| | - Wei Gao
- Department of Biomedical Sciences and Academic Imaging, Cedars-Sinai Medical Center, CA, USA.
| | - Dong Ming
- The Neural Engineering & Rehabilitation lab, Tianjin University, Tianjin, China.
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Farrher E, Lindemeyer J, Grinberg F, Oros-Peusquens AM, Shah NJ. Concerning the matching of magnetic susceptibility differences for the compensation of background gradients in anisotropic diffusion fibre phantoms. PLoS One 2017; 12:e0176192. [PMID: 28467458 PMCID: PMC5415224 DOI: 10.1371/journal.pone.0176192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/06/2017] [Indexed: 11/20/2022] Open
Abstract
Artificial, anisotropic fibre phantoms are nowadays increasingly used in the field of diffusion-weighted MRI. Such phantoms represent useful tools for, among others, the calibration of pulse sequences and validation of diffusion models since they can mimic well-known structural features of brain tissue on the one hand, but exhibit a reduced complexity, on the other. Among all materials, polyethylene fibres have been widely used due to their excellent properties regarding the restriction of water diffusion and surface relaxation properties. Yet the magnetic susceptibility of polyethylene can be distinctly lower than that of distilled water. This difference produces strong microscopic, background field gradients in the vicinity of fibre bundles which are not parallel to the static magnetic field. This, in turn, modulates the MRI signal behaviour. In the present work we investigate an approach to reduce the susceptibility-induced background gradients via reducing the heterogeneity in the internal magnetic susceptibility. An aqueous solution of magnesium chloride hexahydrate (MgCl2·6H2O) is used for this purpose. Its performance is demonstrated in dedicated anisotropic fibre phantoms with different geometrical configurations.
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Affiliation(s)
- Ezequiel Farrher
- Institute of Neuroscience and Medicine – 4, Forschungszentrum Jülich GmbH, Jülich, Germany
- * E-mail:
| | - Johannes Lindemeyer
- Institute of Neuroscience and Medicine – 4, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Farida Grinberg
- Institute of Neuroscience and Medicine – 4, Forschungszentrum Jülich GmbH, Jülich, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | | | - N. Jon Shah
- Institute of Neuroscience and Medicine – 4, Forschungszentrum Jülich GmbH, Jülich, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- JARA – BRAIN – Translational Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine – 11, Forschungszentrum Jülich GmbH, Jülich, Germany
- Department of Electrical and Computer Systems Engineering, and Monash Biomedical Imaging, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
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11
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Ruan W, Zhong J, Guan Y, Xia Y, Zhao X, Han Y, Sun X, Liu S, Ye C, Zhou X. Detection of smoke-induced pulmonary lesions by hyperpolarized129Xe diffusion kurtosis imaging in rat models. Magn Reson Med 2016; 78:1891-1899. [DOI: 10.1002/mrm.26566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/03/2016] [Accepted: 11/09/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Weiwei Ruan
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
- University of Chinese Academy of Sciences; Beijing P. R. China
| | - Jianping Zhong
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
| | - Yu Guan
- Department of Radiology; Changzheng Hospital of the Second Military Medical University; Shanghai China
| | - Yi Xia
- Department of Radiology; Changzheng Hospital of the Second Military Medical University; Shanghai China
| | - Xiuchao Zhao
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
| | - Yeqing Han
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
| | - Xianping Sun
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
- University of Chinese Academy of Sciences; Beijing P. R. China
| | - Shiyuan Liu
- Department of Radiology; Changzheng Hospital of the Second Military Medical University; Shanghai China
| | - Chaohui Ye
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
- University of Chinese Academy of Sciences; Beijing P. R. China
| | - Xin Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan P. R. China
- University of Chinese Academy of Sciences; Beijing P. R. China
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12
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Shaw CB, Jensen JH, Deardorff RL, Spampinato MV, Helpern JA. Comparison of Diffusion Metrics Obtained at 1.5T and 3T in Human Brain With Diffusional Kurtosis Imaging. J Magn Reson Imaging 2016; 45:673-680. [PMID: 27402163 DOI: 10.1002/jmri.25380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/21/2016] [Indexed: 12/23/2022] Open
Abstract
PURPOSE To quantitatively compare diffusion metrics for human brain estimated with diffusional kurtosis imaging (DKI) at applied field strengths of 1.5 and 3T. MATERIALS AND METHODS DKI data for brain were acquired at both 1.5 and 3T from each of six healthy volunteers using a twice-refocused diffusion-weighted imaging sequence. From these data, parametric maps of mean diffusivity (MD), axial diffusivity (D‖ ), radial diffusivity (D⊥ ), fractional anisotropy (FA), mean diffusional kurtosis (MK), axial kurtosis (K‖ ), radial kurtosis (K⊥ ), and kurtosis fractional anisotropy (KFA) were estimated. Comparisons of the results from the two field strengths were made for each metric using both Bland-Altman plots and linear regression to calculate coefficients of determination (R2 ) and best fit lines. RESULTS Diffusion metrics measured at 1.5 and 3T were observed to be similar. Linear regression of the full datasets had coefficients of determination varying from a low of R2 = 0.86 for KFA to a high of R2 = 0.97 for FA. The slopes of the 3T vs. 1.5T best linear fits varied from 0.881 ± 0.009 for KFA to 1.038 ± 0.010 for D‖ . From a Bland-Altman analysis of selected regions of interest, the mean differences of the metrics for the two field strengths were all found to be less than 6%, except for KFA, which showed the largest relative discrepancy of 10%. CONCLUSION Diffusion metrics measured with DKI at 1.5 and 3T are strongly correlated and typically differ by only a few percent. The somewhat higher discrepancy for the KFA is argued to mainly reflect the effects of signal noise. This supports the robustness DKI results with respect to field strength. LEVEL OF EVIDENCE 3 J. Magn. Reson. Imaging 2017;45:673-680.
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Affiliation(s)
- Calvin B Shaw
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Jens H Jensen
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rachael L Deardorff
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Maria Vittoria Spampinato
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Joseph A Helpern
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, USA
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