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Elsayed H, Karjalainen J, Nissi MJ, Ketola J, Kajabi AW, Casula V, Zbýň Š, Nieminen MT, Hanni M. Assessing post-traumatic changes in cartilage using T 1ρ dispersion parameters. Magn Reson Imaging 2023; 97:91-101. [PMID: 36610648 DOI: 10.1016/j.mri.2022.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/10/2022] [Accepted: 12/17/2022] [Indexed: 01/06/2023]
Abstract
Degeneration of cartilage can be studied non-invasively with quantitative MRI. A promising parameter for detecting early osteoarthritis in articular cartilage is T1ρ, which can be tuned via the amplitude of the spin-lock pulse. By measuring T1ρ at several spin-lock amplitudes, the dispersion of T1ρ is obtained. The aim of this study is to find out if the dispersion contains diagnostically relevant information complementary to a T1ρ measurement at a single spin-lock amplitude. To this end, five differently acquired dispersion parameters are utilized; A, B, τc, T1ρ/T2, and R2 - R1ρ. An open dataset of an equine model of post-traumatic cartilage was utilized to assess the T1ρ dispersion parameters for the evaluation of cartilage degeneration. Firstly, the parameters were compared for their sensitivity in detecting degenerative changes. Secondly, the relationship of the dispersion parameters to histological and biomechanical reference parameters was studied. Parameters A, T1ρ/T2, and R2 - R1ρ were found to be sensitive to lesion-induced changes in the cartilage within sample. Strong correlations of several dispersion parameters with optical density, as well as with collagen fibril angle were found. Most of the dispersion parameters correlated strongly with individual T1ρ values. The results suggest that dispersion parameters can in some cases provide a more accurate description of the biochemical composition of cartilage as compared to conventional MRI parameters. However, in most cases the information given by the dispersion parameters is more of a refinement than complementary to conventional quantitative MRI.
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Affiliation(s)
- Hassaan Elsayed
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Jouni Karjalainen
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Mikko J Nissi
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Juuso Ketola
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Abdul Wahed Kajabi
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland; Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Victor Casula
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Štefan Zbýň
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland; Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Miika T Nieminen
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
| | - Matti Hanni
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, P.O.Box 5000, 90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
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Shaffer JJ, Mani M, Schmitz SL, Xu J, Owusu N, Wu D, Magnotta VA, Wemmie JA. Proton Exchange Magnetic Resonance Imaging: Current and Future Applications in Psychiatric Research. Front Psychiatry 2020; 11:532606. [PMID: 33192650 PMCID: PMC7542226 DOI: 10.3389/fpsyt.2020.532606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022] Open
Abstract
Proton exchange provides a powerful contrast mechanism for magnetic resonance imaging (MRI). MRI techniques sensitive to proton exchange provide new opportunities to map, with high spatial and temporal resolution, compounds important for brain metabolism and function. Two such techniques, chemical exchange saturation transfer (CEST) and T1 relaxation in the rotating frame (T1ρ), are emerging as promising tools in the study of neurological and psychiatric illnesses to study brain metabolism. This review describes proton exchange for non-experts, highlights the current status of proton-exchange MRI, and presents advantages and drawbacks of these techniques compared to more traditional methods of imaging brain metabolism, including positron emission tomography (PET) and MR spectroscopy (MRS). Finally, this review highlights new frontiers for the use of CEST and T1ρ in brain research.
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Affiliation(s)
- Joseph J Shaffer
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Merry Mani
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Samantha L Schmitz
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States
| | - Jia Xu
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Nana Owusu
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - Dee Wu
- Department of Radiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Vincent A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - John A Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States.,Department of Veterans Affairs Medical Center, Iowa City, IA, United States.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, United States.,Department of Neurosurgery, University of Iowa, Iowa City, IA, United States
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Zibetti MVW, Baboli R, Chang G, Otazo R, Regatte RR. Rapid compositional mapping of knee cartilage with compressed sensing MRI. J Magn Reson Imaging 2018; 48:1185-1198. [PMID: 30295344 PMCID: PMC6231228 DOI: 10.1002/jmri.26274] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/12/2018] [Indexed: 12/15/2022] Open
Abstract
More than a decade after the introduction of compressed sensing (CS) in MRI, researchers are still working on ways to translate it into different research and clinical applications. The greatest advantage of CS in MRI is the reduced amount of k-space data needed to reconstruct images, which can be exploited to reduce scan time or to improve spatial resolution and volumetric coverage. Efficient data acquisition using CS is extremely important for compositional mapping of the musculoskeletal system in general and knee cartilage mapping techniques in particular. High-resolution quantitative information about tissue biochemical composition could be obtained in just a few minutes using CS MRI. However, in order to make this goal a reality, some issues still need to be addressed. In this article we review the current state of the art of CS methods for rapid compositional mapping of knee cartilage. Specifically, data acquisition strategies, image reconstruction algorithms, and data fitting models are discussed. Different CS studies for T2 and T1ρ mapping of knee cartilage are reviewed, with illustrative results. Future directions, opportunities, and challenges of rapid compositional mapping techniques are also discussed. Level of Evidence: 4 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2018;47:1185-1198.
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Affiliation(s)
- Marcelo V W Zibetti
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Rahman Baboli
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Gregory Chang
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Ricardo Otazo
- Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Ravinder R Regatte
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
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Zibetti MVW, Sharafi A, Otazo R, Regatte RR. Accelerating 3D-T 1ρ mapping of cartilage using compressed sensing with different sparse and low rank models. Magn Reson Med 2018; 80:1475-1491. [PMID: 29479738 DOI: 10.1002/mrm.27138] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/11/2018] [Accepted: 01/26/2018] [Indexed: 12/16/2022]
Abstract
PURPOSE To evaluate the feasibility of using compressed sensing (CS) to accelerate 3D-T1ρ mapping of cartilage and to reduce total scan times without degrading the estimation of T1ρ relaxation times. METHODS Fully sampled 3D-T1ρ datasets were retrospectively undersampled by factors 2-10. CS reconstruction using 12 different sparsifying transforms were compared, including finite differences, temporal and spatial wavelets, learned transforms using principal component analysis (PCA) and K-means singular value decomposition (K-SVD), explicit exponential models, low rank and low rank plus sparse models. Spatial filtering prior to T1ρ parameter estimation was also tested. Synthetic phantom (n = 6) and in vivo human knee cartilage datasets (n = 7) were included. RESULTS Most CS methods performed satisfactorily for an acceleration factor (AF) of 2, with relative T1ρ error lower than 4.5%. Some sparsifying transforms, such as spatiotemporal finite difference (STFD), exponential dictionaries (EXP) and low rank combined with spatial finite difference (L+S SFD) significantly improved this performance, reaching average relative T1ρ error below 6.5% on T1ρ relaxation times with AF up to 10, when spatial filtering was used before T1ρ fitting, at the expense of smoothing the T1ρ maps. The STFD achieved 5.1% error at AF = 10 with spatial filtering prior to T1ρ fitting. CONCLUSION Accelerating 3D-T1ρ mapping of cartilage with CS is feasible up to AF of 10 when using STFD, EXP or L+S SFD regularizers. These three best CS methods performed satisfactorily on synthetic phantom and in vivo knee cartilage for AFs up to 10, with T1ρ error of 6.5%.
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Affiliation(s)
- Marcelo V W Zibetti
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Azadeh Sharafi
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Ricardo Otazo
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Ravinder R Regatte
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
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Biologically aggressive regions within glioblastoma identified by spin-lock contrast T1 relaxation in the rotating frame (T1ρ) MRI. Radiol Case Rep 2017; 12:827-832. [PMID: 29484081 PMCID: PMC5823312 DOI: 10.1016/j.radcr.2017.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/12/2017] [Accepted: 07/03/2017] [Indexed: 11/23/2022] Open
Abstract
Spin-lattice relaxation in the rotating frame magnetic resonance imaging allows for the quantitative assessment of spin-lock contrast within tissues. We describe the utility of spin-lattice relaxation in the rotating frame metrics in characterizing glioblastoma biological heterogeneity. A 84-year-old man presented to our institution with a right frontal temporal mass. Prior tissue sampling from a peripheral nonenhancing lesion was nondiagnostic. Stereotactic image-guided tissue sampling of the nonenhancing T2-fluid-attenuated inversion recovery hyperintense region involving the anterior cingulate gyrus with elevated spin-lattice relaxation in the rotating frame metrics provided a pathologic diagnosis of glioblastoma. This case illustrates the utility of spin-lattice relaxation in the rotating frame magnetic resonance imaging in identifying biologically aggressive regions within glioblastoma.
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Zhang Y, Liu X, Zhou J, Bottomley PA. Ultrafast compartmentalized relaxation time mapping with linear algebraic modeling. Magn Reson Med 2017; 79:286-297. [PMID: 28401643 DOI: 10.1002/mrm.26675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/17/2017] [Accepted: 02/19/2017] [Indexed: 12/28/2022]
Abstract
PURPOSE To dramatically accelerate compartmental-average longitudinal (T1 ) and transverse (T2 ) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. METHODS Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. RESULTS At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0% ± 0.7%, 1.4% ± 3.4%, and 0.5% ± 2.9% for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2% ± 1.9%, 0.9% ± 7.9%, and 0.4% ± 5.8%, respectively. CONCLUSION SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations. Magn Reson Med 79:286-297, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Xiaoyang Liu
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Paul A Bottomley
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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Casula V, Autio J, Nissi MJ, Auerbach EJ, Ellermann J, Lammentausta E, Nieminen MT. Validation and optimization of adiabatic T 1ρ and T 2ρ for quantitative imaging of articular cartilage at 3 T. Magn Reson Med 2016; 77:1265-1275. [PMID: 26946182 DOI: 10.1002/mrm.26183] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 02/02/2016] [Accepted: 02/06/2016] [Indexed: 12/22/2022]
Abstract
PURPOSE The aim of the present work was to validate and optimize adiabatic T1ρ and T2ρ mapping for in vivo measurements of articular cartilage at 3 Tesla (T). METHODS Phantom and in vivo experiments were systematically performed on a 3T clinical system to evaluate the sequences using hyperbolic secant HS1 and HS4 pulses. R1ρ and R2ρ relaxation rates were studied as a function of agarose and chondroitin sulfate concentration and pulse duration. Optimal in vivo protocol was determined by imaging the articular cartilage of two volunteers and varying the sequence parameters, and successively applied in eight additional subjects. Reproducibility was assessed in phantoms and in vivo. RESULTS Relaxation rates depended on agarose and chondroitin sulfate concentration. The sequences were able to generate relaxation time maps with pulse lengths of 8 and 6 ms for HS1 and HS4, respectively. In vivo findings were in good agreement with the phantoms. The implemented adiabatic T1ρ and T2ρ sequences demonstrated regional variation in relaxation time maps of femorotibial cartilage. Reproducibility in phantoms and in vivo was good to excellent for both adiabatic T1ρ and T2ρ . CONCLUSIONS The findings indicate that sequences are suitable for quantitative in vivo assessment of articular cartilage at 3 T. Magn Reson Med 77:1265-1275, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Victor Casula
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Joonas Autio
- Center for Life Science and Technologies, RIKEN, Kobe, Japan
| | - Mikko J Nissi
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN.,Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Edward J Auerbach
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Jutta Ellermann
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | | | - Miika T Nieminen
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
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Han Y, Liimatainen T, Gorman RC, Witschey WRT. Assessing Myocardial Disease Using T 1ρ MRI. CURRENT CARDIOVASCULAR IMAGING REPORTS 2014; 7:9248. [PMID: 24688628 PMCID: PMC3968806 DOI: 10.1007/s12410-013-9248-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
There is great interest to use magnetic resonance imaging (MRI) for non-invasive assessment of myocardial disease in ischemic and non-ischemic cardiomyopathies. Recently, there has been a renewed interest to use a magnetic resonance imaging (MRI) technique utilizing spin locking radiofrequency (RF) pulses, called T1ρ MRI. The spin locking RF pulse creates sensitivity to some mechanisms of nuclear relaxation such as 1H exchange between water and amide, amine and hydroxyl functional groups in molecules; consequently, there is the potential to non-invasively, and without exogenous contrast agents, obtain important molecular information from diseased myocardial tissue. The purpose of this article is to review and critically examine the recent published literature in the field related to T1ρ MRI of myocardial disease.
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Affiliation(s)
- Yuchi Han
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, Hospital of the University of Pennsylvania, 9022 Gates, 3400 Spruce Street, Philadelphia, PA, USA
| | - Timo Liimatainen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Robert C. Gorman
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Blvd, Bldg 421, 7th floor, Rm 103, Philadelphia, PA 19104, USA
| | - Walter R. T. Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Blvd, Bldg 421, 7th floor, Rm 103, Philadelphia, PA 19104, USA
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Johnson CP, Thedens DR, Magnotta VA. Precision-guided sampling schedules for efficient T1ρ mapping. J Magn Reson Imaging 2014; 41:242-50. [PMID: 24474423 DOI: 10.1002/jmri.24518] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 11/01/2013] [Indexed: 02/02/2023] Open
Abstract
PURPOSE To describe, assess, and implement a simple precision estimation framework for optimization of spin-lock time (TSL) sampling schedules for quantitative T1ρ mapping using a mono-exponential signal model. MATERIALS AND METHODS A method is described for estimating T1ρ precision, and a cost function based on the precision estimates is evaluated to determine efficient TSL sampling schedules. The validity of the framework was tested by imaging a phantom with various sampling schedules and comparing theoretical and experimental precision values. The method utility was demonstrated with in vivo T1ρ mapping of brain tissue using a similar procedure as the phantom experiment. To assist investigators, optimal sampling schedules are tabulated for various tissue types and an online calculator is implemented. RESULTS Theoretical and experimental precision values followed similar trends for both the phantom and in vivo experiments. The mean absolute percentage error (MAPE) of theoretical estimates of T1ρ map signal-to-noise ratio (SNR) was typically 5% in the phantom experiment and 33% in the in vivo demonstration. In both experiments, optimal TSL schedules yielded greater T1ρ map SNR efficiency than typical schedules. CONCLUSION The framework can be used to improve the imaging efficiency of T1ρ mapping protocols and to guide selection of imaging parameters.
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Affiliation(s)
- Casey P Johnson
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
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Karaman MM, Bruce IP, Rowe DB. A statistical fMRI model for differential T2* contrast incorporating T1 and T2* of gray matter. Magn Reson Imaging 2013; 32:9-27. [PMID: 24183567 DOI: 10.1016/j.mri.2013.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 08/10/2013] [Accepted: 09/26/2013] [Indexed: 11/25/2022]
Abstract
Relaxation parameter estimation and brain activation detection are two main areas of study in magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI). Relaxation parameters can be used to distinguish voxels containing different types of tissue whereas activation determines voxels that are associated with neuronal activity. In fMRI, the standard practice has been to discard the first scans to avoid magnetic saturation effects. However, these first images have important information on the MR relaxivities for the type of tissue contained in voxels, which could provide pathological tissue discrimination. It is also well-known that the voxels located in gray matter (GM) contain neurons that are to be active while the subject is performing a task. As such, GM MR relaxivities can be incorporated into a statistical model in order to better detect brain activation. Moreover, although the MR magnetization physically depends on tissue and imaging parameters in a nonlinear fashion, a linear model is what is conventionally used in fMRI activation studies. In this study, we develop a statistical fMRI model for Differential T2(*) ConTrast Incorporating T1 and T2(*) of GM, so-called DeTeCT-ING Model, that considers the physical magnetization equation to model MR magnetization; uses complex-valued time courses to estimate T1 and T2(*) for each voxel; then incorporates gray matter MR relaxivities into the statistical model in order to better detect brain activation, all from a single pulse sequence by utilizing the first scans.
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Affiliation(s)
- M Muge Karaman
- Department of Mathematics, Statistics, and Computer Science, Marquette University, Milwaukee, WI, USA
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Yuan J, Zhao F, Griffith JF, Chan Q, Wang YXJ. Optimized efficient liverT1ρmapping using limited spin lock times. Phys Med Biol 2012; 57:1631-40. [DOI: 10.1088/0031-9155/57/6/1631] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Liimatainen T, Sierra A, Hanson T, Sorce DJ, Ylä-Herttuala S, Garwood M, Michaeli S, Gröhn O. Glioma cell density in a rat gene therapy model gauged by water relaxation rate along a fictitious magnetic field. Magn Reson Med 2011; 67:269-77. [PMID: 21721037 DOI: 10.1002/mrm.22997] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/24/2011] [Accepted: 04/18/2011] [Indexed: 11/09/2022]
Abstract
Longitudinal and transverse rotating-frame relaxation time constants, T(1) (ρ) and T(2) (ρ) , have previously been successfully applied to detect gene therapy responses and acute stroke in animal models. Those experiments were performed with continuous-wave irradiation or with frequency-modulated pulses operating in an adiabatic regime. The technique called Relaxation Along a Fictitious Field (RAFF) is a recent extension of frequency-modulated rotating-frame relaxation methods. In RAFF, spin locking takes place along a fictitious magnetic field, and the decay rate is a function of both T(1ρ) and T(2ρ) processes. In this work, the time constant characterizing water relaxation with RAFF (T(RAFF) ) was evaluated for its utility as a marker of response to gene therapy in a rat glioma model. To investigate the sensitivity to early treatment response, we measured several rotating-frame and free-precession relaxation time constants and the water apparent diffusion coefficients, and these were compared with histological cell counts in 8 days of treated and control groups of animals. T(RAFF) was the only parameter exhibiting significant association with cell density in three different tumor regions (border, intermediate, and core tissues). These results indicate that T(RAFF) may provide a marker to identify tumors responding to treatment.
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Affiliation(s)
- Timo Liimatainen
- Department of Biotechnology and Molecular Medicine A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
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Abstract
The cartilage of the lower limb joints is exposed to high levels of mechanical stress and therefore is a frequent site of degenerative and traumatic lesions. Magnetic resonance imaging (MRI) is the modality of choice for the assessment of these cartilage lesions. To date, clinically available sequences have focused on morphological defects and cartilage loss. Efforts have been made in recent years to depict cartilage lesions at an earlier stage, with new quantitative sequences focusing on the biochemical assessment of tissue.After a brief review of the hyaline cartilage structure, we review the current morphological imaging methods and the biochemical MRI techniques to assess the cartilage. We then illustrate the application of these MRI sequences for the most common degenerative and traumatic disorders affecting lower limb cartilage.
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TAKAYAMA Y, HATAKENAKA M, YOSHIURA T, OKAZAKI K, NISHIKAWA K, OKUAKI T, ZIMINE I, HONDA H. A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint. Magn Reson Med Sci 2010; 9:209-15. [DOI: 10.2463/mrms.9.209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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16
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Borthakur A, Sochor M, Davatzikos C, Trojanowski JQ, Clark CM. T1rho MRI of Alzheimer's disease. Neuroimage 2008; 41:1199-205. [PMID: 18479942 PMCID: PMC2473861 DOI: 10.1016/j.neuroimage.2008.03.030] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 02/28/2008] [Accepted: 03/18/2008] [Indexed: 10/22/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Classic symptoms of the disease include memory loss and confusion associated with the hallmark neuro-pathologic lesions of neurofibrillary tangles (NFT) and senile plaques (SP) and their sequelae, gray matter atrophy. Volumetric assessment methods measure tissue atrophy, which typically follows early biochemical changes. An alternate MRI contrast mechanism to visualize the early pathological changes is T1rho (or "T-1-rho"), the spin lattice relaxation time constant in the rotating frame, which determines the decay of the transverse magnetization in the presence of a "spin-lock" radio-frequency field. Macromolecular changes (in plaques and tangles) that accompany early AD are expected to alter bulk water T1rho relaxation times. In this work, we measure T1rho MRI on patients with clinically diagnosed AD, MCI and in age-matched cognitively normal control subjects in order to compare T1rho values with changes in brain volume in the same regions of the brain and demonstrate that T1rho can potentially constitute an important biomarker of AD.
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Affiliation(s)
- Arijitt Borthakur
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA.
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17
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La Rocca Vieira R, Pakin SK, de Albuquerque Cavalcanti CF, Schweitzer M, Regatte R. Three-dimensional spin-lock magnetic resonance imaging of the shoulder joint at 3 T: initial experience. Skeletal Radiol 2007; 36:1171-5. [PMID: 17912522 DOI: 10.1007/s00256-007-0368-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/02/2007] [Accepted: 07/04/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVES This was a pilot study which aimed to assess the feasibility of 3D-spin-lock (3D-T(1rho)) MRI of the shoulder joint and to establish baseline values of healthy humeral and glenoid cartilages in vivo. MATERIAL AND METHODS Four asymptomatic volunteers [mean age 31 years (range 29-36 years)] were recruited. A 3.0 T scanner, employing a four-channel, phased-array, shoulder, radio-frequency (RF) coil was used. Three-dimensional T(1rho)-weighted images were acquired with a 3D gradient-echo (GRE) sequence with T(1rho) magnetization preparation. In order to a construct T(1rho) map, we acquired four 3D-T(1rho)-weighted images with spin-locking length (TSL) values of 2 ms, 10 ms, 20 ms, and 30 ms. The glenoid and humeral cartilage were segmented manually at each slice of the 3D images. We performed additional regional analysis by dividing the cartilage into anterior/posterior and superior/inferior regions. RESULTS The global average T(1rho) value of the shoulder cartilages varied from 37.9 ms to 48.5 ms and from 32.4 ms to 36.9 ms for humeral and glenoid cartilages, respectively. In the humeral cartilage, the average regional T(1rho) values varied from 35.9 ms to 52.2 ms; 54.4 ms to 69.0 ms; 39.1 ms to 49.3 ms and 34.6 ms to 57.2 ms for the anterior-superior, anterior-inferior , posterior-superior and posterior-inferior regions, respectively. In the glenoid cartilage, the values varied from 31.3 ms to 40.8 ms; 34.1 ms to 35.3 ms; 26.7 ms to 37.2 ms and 32.8 ms to 35.7 ms for the same regions, respectively. CONCLUSION We demonstrated that 3D-T(1rho) MRI of the shoulder can be performed on a 3 T clinical scanner within specific absorption rate (SAR) limits, and we present baseline values for healthy patients which may be useful for quantitative comparison with diseased shoulders.
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Affiliation(s)
- Renata La Rocca Vieira
- Radiology Department, NYU Hospital for Joint Diseases, New York University School of Medicine, New York, NY, USA.
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Kettunen MI, Sierra A, Närväinen MJ, Valonen PK, Ylä-Herttuala S, Kauppinen RA, Gröhn OHJ. Low Spin-Lock Field T1 Relaxation in the Rotating Frame as a Sensitive MR Imaging Marker for Gene Therapy Treatment Response in Rat Glioma1. Radiology 2007; 243:796-803. [PMID: 17517934 DOI: 10.1148/radiol.2433052077] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively assess the effectiveness of T1 relaxation in the rotating frame (T1 rho) dispersion and the low spin-lock radiofrequency field (B(1)) T1 rho magnetic resonance (MR) imaging relaxation time in noninvasive monitoring of gene therapy response in BT4C glioma in rats. MATERIALS AND METHODS All animal studies were approved by the ethical committee of the National Laboratory Animal Center. Rats with BT4C gliomas (n=9) were treated with herpes simplex virus thymidine kinase gene therapy and were compared with untreated rats (n=5). Absolute T1 rho at a B(1) range of 2.0 x 10(-6) to 1.4 x 10(-4) T, T1, T2, and apparent diffusion constant were measured at 4.7 T during treatment. Statistical significance was tested by using repeated-measures analysis of variance. RESULTS A significant (P<.05) lengthening of T1 rho was observed beginning on the 4th day of treatment, and T1 rho values increased to be approximately 80% higher than values observed before treatment. These changes preceded T1 and T2 changes and resembled those of water diffusion. The T1 rho was associated with a treatment-induced decrease in cell density; this was the only measured MR imaging property that provided significant (P<.05) Pearson correlation with cell density in the tumor border. T1 rho relaxation dispersion, however, did not offer additional benefits over those offered in one B(1) experiment in the early phase of treatment. CONCLUSION T1 rho with low B(1) is an excellent MR imaging marker of early gene therapy response in gliomas. The low B(1) approach is not limited by specific absorption rate restrictions; this finding suggests that spin-lock methods could be applicable in clinical settings. (
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Affiliation(s)
- Mikko I Kettunen
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland.
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19
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Borthakur A, Mellon E, Niyogi S, Witschey W, Kneeland JB, Reddy R. Sodium and T1rho MRI for molecular and diagnostic imaging of articular cartilage. NMR IN BIOMEDICINE 2006; 19:781-821. [PMID: 17075961 PMCID: PMC2896046 DOI: 10.1002/nbm.1102] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this article, both sodium magnetic resonance (MR) and T1rho relaxation mapping aimed at measuring molecular changes in cartilage for the diagnostic imaging of osteoarthritis are reviewed. First, an introduction to structure of cartilage, its degeneration in osteoarthritis (OA) and an outline of diagnostic imaging methods in quantifying molecular changes and early diagnostic aspects of cartilage degeneration are described. The sodium MRI section begins with a brief overview of the theory of sodium NMR of biological tissues and is followed by a section on multiple quantum filters that can be used to quantify both bi-exponential relaxation and residual quadrupolar interaction. Specifically, (i) the rationale behind the use of sodium MRI in quantifying proteoglycan (PG) changes, (ii) validation studies using biochemical assays, (iii) studies on human OA specimens, (iv) results on animal models and (v) clinical imaging protocols are reviewed. Results demonstrating the feasibility of quantifying PG in OA patients and comparison with that in healthy subjects are also presented. The section concludes with the discussion of advantages and potential issues with sodium MRI and the impact of new technological advancements (e.g. ultra-high field scanners and parallel imaging methods). In the theory section on T1rho, a brief description of (i) principles of measuring T1rho relaxation, (ii) pulse sequences for computing T1rho relaxation maps, (iii) issues regarding radio frequency power deposition, (iv) mechanisms that contribute to T1rho in biological tissues and (v) effects of exchange and dipolar interaction on T1rho dispersion are discussed. Correlation of T1rho relaxation rate with macromolecular content and biomechanical properties in cartilage specimens subjected to trypsin and cytokine-induced glycosaminoglycan depletion and validation against biochemical assay and histopathology are presented. Experimental T1rho data from osteoarthritic specimens, animal models, healthy human subjects and as well from osteoarthritic patients are provided. The current status of T1rho relaxation mapping of cartilage and future directions is also discussed.
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Affiliation(s)
- Arijitt Borthakur
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Eric Mellon
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Sampreet Niyogi
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Walter Witschey
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - J. Bruce Kneeland
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Ravinder Reddy
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
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20
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Eckstein F, Burstein D, Link TM. Quantitative MRI of cartilage and bone: degenerative changes in osteoarthritis. NMR IN BIOMEDICINE 2006; 19:822-54. [PMID: 17075958 DOI: 10.1002/nbm.1063] [Citation(s) in RCA: 242] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Magnetic resonance imaging (MRI) and quantitative image analysis technology has recently started to generate a great wealth of quantitative information on articular cartilage and bone physiology, pathophysiology and degenerative changes in osteoarthritis. This paper reviews semiquantitative scoring of changes of articular tissues (e.g. WORMS = whole-organ MRI scoring or KOSS = knee osteoarthritis scoring system), quantification of cartilage morphology (e.g. volume and thickness), quantitative measurements of cartilage composition (e.g. T2, T1rho, T1Gd = dGEMRIC index) and quantitative measurement of bone structure (e.g. app. BV/TV, app. TbTh, app. Tb.N, app. Tb.Sp) in osteoarthritis. For each of these fields we describe the hardware and MRI sequences available, the image analysis systems and techniques used to derive semiquantitative and quantitative parameters, the technical accuracy and precision of the measurements reported to date and current results from cross-sectional and longitudinal studies in osteoarthritis. Moreover, the paper summarizes studies that have compared MRI-based measurements with radiography and discusses future perspectives of quantitative MRI in osteoarthritis. In summary, the above methodologies show great promise for elucidating the pathophysiology of various tissues and identifying risk factors of osteoarthritis, for developing structure modifying drugs (DMOADs) and for combating osteoarthritis with new and better therapy.
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Affiliation(s)
- Felix Eckstein
- Institute of Anatomy and Musculoskeletal Research, Paracelsus Private Medical University (PMU), A-5020 Salzburg, Austria.
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21
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Pakin SK, Xu J, Schweitzer ME, Regatte RR. Rapid 3D-T1ρ mapping of the knee joint at 3.0T with parallel imaging. Magn Reson Med 2006; 56:563-71. [PMID: 16894582 DOI: 10.1002/mrm.20982] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Three-dimensional spin-lattice relaxation time in the rotating frame (3D-T1rho) with parallel imaging at 3.0T was implemented on a whole-body clinical scanner. A 3D gradient-echo sequence with a self-compensating spin-lock pulse cluster was combined with generalized autocalibrating partially parallel acquisitions (GRAPPA) to acquire T1rho-weighted images. 3D-T1rho maps of an agarose phantom and three healthy subjects were constructed using an eight-channel phased-array coil without parallel imaging and with parallel imaging acceleration factors of 2 and 3, in order to assess the reproducibility of the method. The coefficient of variation (CV) of the median T1rho of the agarose phantom was 0.44%, which shows excellent reproducibility. The reproducibility of in vivo 3D-T1rho maps was also investigated in three healthy subjects. The CV of the median T1rho of the patellar cartilage varied between approximately 1.1% and 4.3%. Similarly, the CV varied between approximately 2.1-5.8%, approximately 1.4-8.7%, and approximately 1.5-4.1% for the biceps femoris and lateral and medial gastrocnemius muscles, respectively. The preliminary results demonstrate that 3D-T1rho maps can be constructed with good reproducibility using parallel imaging. 3D-T1rho with parallel imaging capability is an important clinical tool for reducing both the total acquisition time and RF energy deposition at 3T.
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Affiliation(s)
- S Kubilay Pakin
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA.
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22
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Pakin SK, Schweitzer ME, Regatte RR. 3D-T1ρ quantitation of patellar cartilage at 3.0T. J Magn Reson Imaging 2006; 24:1357-63. [PMID: 17058202 DOI: 10.1002/jmri.20733] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of three-dimensional (3D) T(1rho)-weighted imaging of human knee joint at 3.0T without exceeding the specific absorption rate (SAR) limits and the measurement of the baseline T(1rho) values of patellar cartilage and several muscles at the knee joint. MATERIALS AND METHODS 3D gradient-echo sequence with a self-compensating spin-lock pulse cluster of 250 Hz power was used to acquire 3D-T(1rho)-weighted images of the knee joint of five healthy subjects. Global and regional analysis of patellar cartilage T(1rho) were performed. Furthermore, T(1rho) of several periarticular muscles were analyzed. RESULTS The global average T(1rho) value of the patellar cartilage varied from 39 to 43 msec. The regional average T(1rho) values varied from 38 to 42 msec, and from 42 to 44 msec for medial and lateral facets, respectively. In vivo reproducibility of average T(1rho) of patellar cartilage was found to be 5% (coefficient of variation). Similarly, the global average T(1rho) values for biceps femoris, lateral gastrocnemius, medial gastrocnemius, and sartorius varied between 31-46, 29-49, 35-48, and 32-50 msec, respectively. CONCLUSION We demonstrated the feasibility of 3D-T(1rho)-weighted imaging of the knee joint at 3.0T without exceeding SAR limits.
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Wheaton AJ, Borthakur A, Corbo M, Charagundla SR, Reddy R. Method for reduced SART1?-weighted MRI. Magn Reson Med 2004; 51:1096-102. [PMID: 15170827 DOI: 10.1002/mrm.20141] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A reduced specific absorption rate (SAR) version of the T(1rho)-weighted MR pulse sequence was designed and implemented. The reduced SAR method employs a partial k-space acquisition approach in which a full power spin-lock pulse is applied to only the central phase-encode lines of k-space, while the remainder of k-space receives a low-power spin-lock pulse. Acquisition of high- and low-power phase-encode lines are interspersed chronologically to minimize average power deposition. In this way, the majority of signal energy in the central portion of k-space receives full T(1rho)-weighting, while the average SAR of the overall acquisition can be reduced, thereby lowering the minimum safely allowable TR. The pulse sequence was used to create T(1rho) maps of a phantom, an in vivo mouse brain, and the brain of a human volunteer. In the images of the human brain, SAR was reduced by 40% while the measurements of T(1rho) differed by only 2%. The reduced SAR sequence enables T(1rho)-weighted MRI in a clinical setting, even at high field strengths.
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Affiliation(s)
- Andrew J Wheaton
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Wheaton AJ, Casey FL, Gougoutas AJ, Dodge GR, Borthakur A, Lonner JH, Schumacher HR, Reddy R. Correlation of T1? with fixed charge density in cartilage. J Magn Reson Imaging 2004; 20:519-25. [PMID: 15332262 DOI: 10.1002/jmri.20148] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To establish the specificity of T1rho with respect to fixed charge density (FCD) as a measure of proteoglycan (PG) content in cartilage during the onset of osteoarthritis (OA). MATERIALS AND METHODS T1rho-weighted and sodium MRI were performed on cartilage samples of enzymatically degraded bovine explants and natural osteoarthritic human samples representing controlled and physiological models of OA, respectively. Spatial maps of T1rho and FCD (measured using the previously validated method of sodium MRI) were calculated from image data. Data were extracted from the maps and subjected to linear regression to compare changes in T1rho with changes in FCD in each model. Tissue samples were subjected to histological staining for a reduction in PG content. RESULTS Plots of normalized T1rho rate vs. FCD were found to be strongly correlated (R2 > 0.75 and 0.85) in both models with nearly the same slope of approximately 1/2 (P > 0.51). Loss of PG in bovine and human tissue was confirmed by histology. CONCLUSION The strong correlation of the FCD and T1rho data in both the controlled and physiological models demonstrates that changes in T1rho are due predominantly to changes in PG content. This work is a first step in establishing T1rho as a method of quantifying PG changes in early-stage OA.
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Affiliation(s)
- Andrew J Wheaton
- Department of Radiology, University of Pennsylvania, Philadelphia, USA.
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