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Santini T, Chen C, Zhu W, Liou JJ, Walker E, Venkatesh S, Farhat N, Sajewski A, Alkhateeb S, Saranathan M, Xia Z, Ibrahim TS. Hippocampal subfields and thalamic nuclei associations with clinical outcomes in multiple sclerosis: An ultrahigh field MRI study. Mult Scler Relat Disord 2024; 86:105520. [PMID: 38582026 DOI: 10.1016/j.msard.2024.105520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/14/2024] [Accepted: 02/25/2024] [Indexed: 04/08/2024]
Abstract
BACKGROUND Previous studies have shown that thalamic and hippocampal neurodegeneration is associated with clinical decline in Multiple Sclerosis (MS). However, contributions of the specific thalamic nuclei and hippocampal subfields require further examination. OBJECTIVE Using 7 Tesla (7T) magnetic resonance imaging (MRI), we investigated the cross-sectional associations between functionally grouped thalamic nuclei and hippocampal subfields volumes and T1 relaxation times (T1-RT) and subsequent clinical outcomes in MS. METHODS High-resolution T1-weighted and T2-weighted images were acquired at 7T (n=31), preprocessed, and segmented using the Thalamus Optimized Multi Atlas Segmentation (THOMAS, for thalamic nuclei) and the Automatic Segmentation of Hippocampal Subfields (ASHS, for hippocampal subfields) packages. We calculated Pearson correlations between hippocampal subfields and thalamic nuclei volumes and T1-RT and subsequent multi-modal rater-determined and patient-reported clinical outcomes (∼2.5 years after imaging acquisition), correcting for confounders and multiple tests. RESULTS Smaller volume bilaterally in the anterior thalamus region correlated with worse performance in gait function, as measured by the Patient Determined Disease Steps (PDDS). Additionally, larger volume in most functional groups of thalamic nuclei correlated with better visual information processing and cognitive function, as measured by the Symbol Digit Modalities Test (SDMT). In bilateral medial and left posterior thalamic regions, there was an inverse association between volumes and T1-RT, potentially indicating higher tissue degeneration in these regions. We also observed marginal associations between the right hippocampal subfields (both volumes and T1-RT) and subsequent clinical outcomes, though they did not survive correction for multiple testing. CONCLUSION Ultrahigh field MRI identified markers of structural damage in the thalamic nuclei associated with subsequently worse clinical outcomes in individuals with MS. Longitudinal studies will enable better understanding of the role of microstructural integrity in these brain regions in influencing MS outcomes.
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Affiliation(s)
- Tales Santini
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Chenyi Chen
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Wen Zhu
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jr-Jiun Liou
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elizabeth Walker
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Shruthi Venkatesh
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Nadim Farhat
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Andrea Sajewski
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Salem Alkhateeb
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Zongqi Xia
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.
| | - Tamer S Ibrahim
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States; Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States.
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Abstract
Schizophrenia and related psychoses are complex neuropsychiatric diseases representing dysconnectivity across multiple scales, through the micro (cellular), meso (brain network), manifest (behavioral), and social (interpersonal) levels. In vivo human neuroimaging, particularly at ultra-high field (UHF), offers unprecedented opportunity to examine multiscale dysconnectivity in psychosis. In this review, we provide an overview of the literature to date on UHF in psychosis, focusing on microscale findings from magnetic resonance spectroscopy (MRS), mesoscale studies on structural and functional magnetic resonance imaging (fMRI), and multiscale studies assessing multiple neuroimaging modalities and relating UHF findings to behavior. We highlight key insights and considerations from multiscale and longitudinal studies and provide recommendations for future research on UHF neuroimaging in psychosis.
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Affiliation(s)
- Katie M Lavigne
- Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.,Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Kesavi Kanagasabai
- Robarts Research Institute, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
| | - Lena Palaniyappan
- Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada.,Robarts Research Institute, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
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Nemani A, Lowe MJ. Seed-based test-retest reliability of resting state functional magnetic resonance imaging at 3T and 7T. Med Phys 2021; 48:5756-5764. [PMID: 34486120 DOI: 10.1002/mp.15210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 05/08/2021] [Accepted: 08/20/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Ultrahigh field (UHF) resting state functional magnetic resonance imaging (rsfMRI) has become increasingly available for clinical and basic research, bringing improvements in resolution and contrast over standard high field imaging. Despite these improvements, UHF connectivity studies present several challenges, including increased sensitivity to physiological confounds and a vastly increased data burden. We present a direct quantitative assessment of test-retest reliability of functional connectivity in several standard functional networks between subjects scanned at 3T and 7T. METHODS Five healthy subjects were scanned over four sessions each in a scan-rescan design at both 3T and 7T field strengths. Resting state fMRI data were segmented into four major intrinsic connectivity networks, and seed-based peak correlations within and between these networks examined. The reliability of these correlations was assessed using intra-class correlation coefficients (ICC). RESULTS Across all data, over 4000 peak correlations were extracted for assessment. The reliability over all intrinsic networks was greater at 7T than 3T (median ICC 0.40 vs. 0.33, p ≤ 0.0014), with each network individually showing improvement. Inter-network reliability was stronger than intra-network reliability, but intra-network reliability showed the greatest improvement between field strengths. CONCLUSION We demonstrate significantly increased reliability of resting state connectivity at UHF strengths over conventional field strengths using a novel hybrid seed-based analysis. This result adds to the growing body of work supporting the migration of functional imaging studies to UHFs.
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Affiliation(s)
- Ajay Nemani
- Imaging Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Mark J Lowe
- Imaging Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Abstract
After introduction of the first human 7 tesla (7T) system in 1999, 7T MR systems have been employed as one of the most advanced platforms for human MR research for more than 20 years. Currently, two 7T MR models are approved for clinical use in the U.S.A. The approval facilitated introduction of the 7T system, summing up to around 100 worldwide. The approval in Japan is much awaited. As a clinical MR scanner, the 7T MR system is drawing attention in terms of safety.Several large-sized studies on bioeffects have been reported for vertigo, dizziness, motion disturbances, nausea, and others. Such effects might also be found in MR workers and researchers. Frequency and severity of reported bioeffects will be presented and discussed, including their variances. The high resonance frequency and shorter RF wavelength of 7T increase the concern about the safety. Homogeneous RF pulse excitation is difficult even for the brain, and a multi-channel parallel transmit (pTx) system is considered mandatory. However, pTx may create a hot spot, which makes the estimation of specific absorption rate (SAR) to be difficult. The stronger magnetic field of 7T causes a large force of displacement and heating on metallic implants or devices, and the scan of patients with them should not be conducted at 7T. However, there are some opinions that such patients might be scanned even at 7T, if certain criteria are met. This article provides a brief review on the effect of the static magnetic field on humans (MR subjects, workers, and researchers) and neurons, in addition to scan sound, SAR, and metal implants and devices. Understanding and avoiding adverse effects will contribute to the reduction in safety risks and the prevention of incidents.
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Affiliation(s)
- Tomohisa Okada
- Human Brain Research Center, Graduate School of Medicine, Kyoto University
| | - Thai Akasaka
- Human Brain Research Center, Graduate School of Medicine, Kyoto University
| | - Dinh Hd Thuy
- Human Brain Research Center, Graduate School of Medicine, Kyoto University
| | - Tadashi Isa
- Human Brain Research Center, Graduate School of Medicine, Kyoto University
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Liu J, Beck ES, Filippini S, van Gelderen P, de Zwart JA, Norato G, Sati P, Al-Louzi O, Kolb H, Donadieu M, Morrison M, Duyn JH, Reich DS. Navigator-Guided Motion and B0 Correction of T2*-Weighted Magnetic Resonance Imaging Improves Multiple Sclerosis Cortical Lesion Detection. Invest Radiol 2021; 56:409-416. [PMID: 34086012 PMCID: PMC8269363 DOI: 10.1097/rli.0000000000000754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cortical lesions are common in multiple sclerosis (MS). T2*-weighted (T2*w) imaging at 7 T is relatively sensitive for cortical lesions, but quality is often compromised by motion and main magnetic field (B0) fluctuations. PURPOSE The aim of this study was to determine whether motion and B0 correction with a navigator-guided gradient-recalled echo sequence can improve cortical lesion detection in T2*w magnetic resonance imaging. MATERIALS AND METHODS In this prospective study, a gradient-recalled echo sequence incorporating a navigator allowing for motion and B0 field correction was applied to collect T2*w images at 7 T from adults with MS between August 2019 and March 2020. T2*-weighted images were acquired in 1 to 3 partially overlapping scans per individual and were reconstructed using global average B0 correction ("uncorrected") or motion correction and spatially linear B0 correction ("corrected"). Image quality rating and manual segmentation of cortical lesions were performed on uncorrected and corrected images. Lesions seen on a single scan were retrospectively evaluated on the complementary scan. The association of cortical lesions with clinical disability was assessed. Mixed models were used to determine the effect of correction on lesion detection as well as on the relationship between disability and lesion count. RESULTS A total of 22 T2*w scans were performed on 11 adults with MS (mean [SD] age, 49 [11] years; 8 women). Quality improved for 20 of 22 scans (91%) after correction. A total of 69 cortical lesions were identified on uncorrected images (median per scan, 2; range, 0-11) versus 148 on corrected images (median per scan, 4.5; range, 0-25; rate ratio [RR], 2.1; P < 0.0001). For low-quality uncorrected scans with moderate to severe motion artifact (18/22, 82%), there was an improvement in cortical lesion detection with correction (RR, 2.5; P < 0.0001), whereas there was no significant change in cortical lesion detection for high-quality scans (RR, 1.3; P = 0.43). CONCLUSIONS Navigator-guided motion and B0 correction substantially improves the overall image quality of T2*w magnetic resonance imaging at 7 T and increases its sensitivity for cortical lesions.
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Affiliation(s)
- Jiaen Liu
- Advanced MRI Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Erin S Beck
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
| | - Stefano Filippini
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
- Department of Neurosciences, Drug, and Child Health, University of Florence, Florence, Italy
| | - Peter van Gelderen
- Advanced MRI Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Jacco A de Zwart
- Advanced MRI Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Gina Norato
- Clinical Trials Unit, NINDS, NIH, Bethesda, MD, USA
| | - Pascal Sati
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Omar Al-Louzi
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
| | - Hadar Kolb
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
| | - Maxime Donadieu
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
| | - Mark Morrison
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
| | - Jeff H Duyn
- Advanced MRI Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Daniel S Reich
- Translational Neuroradiology Section, NINDS, NIH, Bethesda, MD, USA
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Utzschneider M, Müller M, Gast LV, Lachner S, Behl NGR, Maier A, Uder M, Nagel AM. Towards accelerated quantitative sodium MRI at 7 T in the skeletal muscle: Comparison of anisotropic acquisition- and compressed sensing techniques. Magn Reson Imaging 2020; 75:72-88. [PMID: 32979516 DOI: 10.1016/j.mri.2020.09.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/25/2020] [Accepted: 09/14/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To compare three anisotropic acquisition schemes and three compressed sensing (CS) approaches for accelerated tissue sodium concentration (TSC) quantification using 23Na MRI at 7 T. MATERIALS AND METHODS Three anisotropic 3D-radial acquisition sequences were evaluated using simulations, phantom- and in vivo TSC measurements: An anisotropic density-adapted 3D-radial sequence (3DPR-C), a 3D acquisition-weighted density-adapted stack-of-stars sampling scheme (SOS) and a SOS approach with golden-ratio rotation (SOS-GR). Eight healthy volunteers were examined at a 7 Tesla MRI system. TSC measurements of the calf were conducted with a nominal spatial resolution of Δx = (3.0 × 3.0 × 15.0) mm3 and a field of view of (156.0 × 156.0 × 240.0) mm3 for multiple undersampling factors (USF). Three CS reconstructions were evaluated: Total variation CS (TV-CS), 3D dictionary-learning compressed sensing (3D-DLCS) and TV-CS with a block matching prior (TV-BL-CS). Results of the simulations and measurements were compared to a simulated ground truth (GT) or a fully sampled reference measurement (FS), respectively. The deviation of the mean TSC evaluated in multiple ROI (mEGT/FS) and the normalized root-mean-squared error (NRMSE) for simulations were evaluated for CS and NUFFT reconstructions. RESULTS In simulations, the SOS-GR yielded the lowest NRMSE and mEGT (< 4%) with NUFFT for an acquisition time (TA) of less than 2 min. CS further improved the results. In simulations and measurements, the best TSC quantification results were obtained with 3D-DLCS and SOS-GR (lowest NRMSE, mEGT < 2.6% in simulations, mEGT < 10.7% for phantom measurements and mEFS < 6% in vivo) with an USF = 4.1 (TA < 2 min). TV-CS showed no or only slight improvements to NUFFT. The results of TV-BL-CS were similar to 3D-DLCS. DISCUSSION The TA for TSC measurements could be reduced to less than 2 min by using adapted sequences such as SOS-GR and CS reconstruction approaches such as 3D-DLCS or TV-BL-CS, while the quantitative accuracy stays comparable to a fully sampled NUFFT reconstruction (approx. 8 min TA). In future, the lower TA could improve clinical applicability of TSC measurements.
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Affiliation(s)
- Matthias Utzschneider
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Max Müller
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Lena V Gast
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sebastian Lachner
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Nicolas G R Behl
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andreas Maier
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Armin M Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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Rua C, Clarke WT, Driver ID, Mougin O, Morgan AT, Clare S, Francis S, Muir KW, Wise RG, Carpenter TA, Williams GB, Rowe JB, Bowtell R, Rodgers CT. Multi-centre, multi-vendor reproducibility of 7T QSM and R 2* in the human brain: Results from the UK7T study. Neuroimage 2020; 223:117358. [PMID: 32916289 DOI: 10.1016/j.neuroimage.2020.117358] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022] Open
Abstract
Introduction We present the reliability of ultra-high field T2* MRI at 7T, as part of the UK7T Network's “Travelling Heads” study. T2*-weighted MRI images can be processed to produce quantitative susceptibility maps (QSM) and R2* maps. These reflect iron and myelin concentrations, which are altered in many pathophysiological processes. The relaxation parameters of human brain tissue are such that R2* mapping and QSM show particularly strong gains in contrast-to-noise ratio at ultra-high field (7T) vs clinical field strengths (1.5–3T). We aimed to determine the inter-subject and inter-site reproducibility of QSM and R2* mapping at 7T, in readiness for future multi-site clinical studies. Methods Ten healthy volunteers were scanned with harmonised single- and multi-echo T2*-weighted gradient echo pulse sequences. Participants were scanned five times at each “home” site and once at each of four other sites. The five sites had 1× Philips, 2× Siemens Magnetom, and 2× Siemens Terra scanners. QSM and R2* maps were computed with the Multi-Scale Dipole Inversion (MSDI) algorithm (https://github.com/fil-physics/Publication-Code). Results were assessed in relevant subcortical and cortical regions of interest (ROIs) defined manually or by the MNI152 standard space. Results and Discussion Mean susceptibility (χ) and R2* values agreed broadly with literature values in all ROIs. The inter-site within-subject standard deviation was 0.001–0.005 ppm (χ) and 0.0005–0.001 ms−1 (R2*). For χ this is 2.1–4.8 fold better than 3T reports, and 1.1–3.4 fold better for R2*. The median ICC from within- and cross-site R2* data was 0.98 and 0.91, respectively. Multi-echo QSM had greater variability vs single-echo QSM especially in areas with large B0 inhomogeneity such as the inferior frontal cortex. Across sites, R2* values were more consistent than QSM in subcortical structures due to differences in B0-shimming. On a between-subject level, our measured χ and R2* cross-site variance is comparable to within-site variance in the literature, suggesting that it is reasonable to pool data across sites using our harmonised protocol. Conclusion The harmonized UK7T protocol and pipeline delivers on average a 3-fold improvement in the coefficient of reproducibility for QSM and R2* at 7T compared to previous reports of multi-site reproducibility at 3T. These protocols are ready for use in multi-site clinical studies at 7T.
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Grochowski C, Symms M, Jonak K, Krukow P, Wood T, Ljungberg E, Enseñat J, Nowomiejska K, Rejdak R, Maciejewski R, Barker GJ. The Evaluation of Optic Nerves Using 7 Tesla "Silent" Zero Echo Time Imaging in Patients with Leber's Hereditary Optic Neuropathy with or without Idebenone Treatment. J Clin Med 2020; 9:E1112. [PMID: 32295018 DOI: 10.3390/jcm9041112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 11/16/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) of the Optic Nerve is difficult due to the fine extended nature of the structure, strong local magnetic field distortions induced by anatomy, and large motion artefacts associated with eye movement. To address these problems we used a Zero Echo Time (ZTE) MRI sequence with an Adiabatic SPectral Inversion Recovery (ASPIR) fat suppression pulse which also imbues the images with Magnetisation Transfer contrast. We investigated an application of the sequence for imaging the optic nerve in subjects with Leber's hereditary optic neuropathy (LHON). Of particular note is the sequence's near-silent operation, which can enhance image quality of the optic nerve by reducing the occurrence of involuntary saccades induced during Magnetic Resonance (MR) scanning.
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Groenendijk IM, Luijten SPR, de Zeeuw CI, Holstege JC, Scheepe JR, van der Zwaag W, Blok BFM. Whole brain 7T-fMRI during pelvic floor muscle contraction in male subjects. Neurourol Urodyn 2019; 39:382-392. [PMID: 31724214 PMCID: PMC7004158 DOI: 10.1002/nau.24218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/25/2019] [Indexed: 12/18/2022]
Abstract
Aim The primary aim of this study is to demonstrate that 7‐tesla functional magnetic resonance imaging (7T‐fMRI) can visualize the neural representations of the male pelvic floor in the whole brain of a single subject. Methods In total, 17 healthy male volunteers (age 20‐47) were scanned in a 7T‐MRI scanner (Philips Achieva). The scanning protocol consisted of two functional runs using a multiband echo planar imaging sequence and a T1‐weighted scan. The subjects executed two motor tasks, one involving consecutive pelvic floor muscle contractions (PFMC) and a control task with tongue movements. Results In single subjects, results of both tasks were visualized in the cortex, putamen, thalamus, and the cerebellum. Activation was seen during PFMC in the superomedial and inferolateral primary motor cortex (M1), supplementary motor area (SMA), insula, midcingulate gyrus (MCG), putamen, thalamus, and in the anterior and posterior lobes of the cerebellum. During tongue movement, activation was seen in the inferolateral M1, SMA, MCG, putamen, thalamus, and anterior and posterior lobes of the cerebellum. Tongue activation was found in the proximity of, but not overlapping with, the PFMC activation. Connectivity analysis demonstrated differences in neural networks involved in PFMC and tongue movement. Conclusion This study demonstrated that 7T‐fMRI can be used to visualize brain areas involved in pelvic floor control in the whole brain of single subjects and defined the specific brain areas involved in PFMC. Distinct differences between brain mechanisms controlling the pelvic floor and tongue movements were demonstrated using connectivity analysis.
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Affiliation(s)
- Ilse M Groenendijk
- Department of Urology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sven P R Luijten
- Department of Urology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Chris I de Zeeuw
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands.,Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Joan C Holstege
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jeroen R Scheepe
- Department of Urology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Bertil F M Blok
- Department of Urology, Erasmus Medical Center, Rotterdam, The Netherlands
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Clarke WT, Mougin O, Driver ID, Rua C, Morgan AT, Asghar M, Clare S, Francis S, Wise RG, Rodgers CT, Carpenter A, Muir K, Bowtell R. Multi-site harmonization of 7 tesla MRI neuroimaging protocols. Neuroimage 2020; 206:116335. [PMID: 31712167 DOI: 10.1016/j.neuroimage.2019.116335] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 10/25/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022] Open
Abstract
Increasing numbers of 7 T (7 T) magnetic resonance imaging (MRI) scanners are in research and clinical use. 7 T MRI can increase the scanning speed, spatial resolution and contrast-to-noise-ratio of many neuroimaging protocols, but technical challenges in implementation have been addressed in a variety of ways across sites. In order to facilitate multi-centre studies and ensure consistency of findings across sites, it is desirable that 7 T MRI sites implement common high-quality neuroimaging protocols that can accommodate different scanner models and software versions. With the installation of several new 7 T MRI scanners in the United Kingdom, the UK7T Network was established with an aim to create a set of harmonized structural and functional neuroimaging sequences and protocols. The Network currently includes five sites, which use three different scanner platforms, provided by two different vendors. Here we describe the harmonization of functional and anatomical imaging protocols across the three different scanner models, detailing the necessary changes to pulse sequences and reconstruction methods. The harmonized sequences are fully described, along with implementation details. Example datasets acquired from the same subject on all Network scanners are made available. Based on these data, an evaluation of the harmonization is provided. In addition, the implementation and validation of a common system calibration process is described.
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Moser P, Bogner W, Hingerl L, Heckova E, Hangel G, Motyka S, Trattnig S, Strasser B. Non-Cartesian GRAPPA and coil combination using interleaved calibration data - application to concentric-ring MRSI of the human brain at 7T. Magn Reson Med 2019; 82:1587-1603. [PMID: 31183893 PMCID: PMC6772100 DOI: 10.1002/mrm.27822] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE Proton MR spectroscopic imaging (MRSI) benefits from B0 ≥ 7T and multichannel receive coils, promising substantial resolution improvements. However, MRSI acquisition with high spatial resolution requires efficient acceleration and coil combination. To speed up the already-fast sampling via concentric rings, we implemented additional, non-Cartesian, hybrid through-time/through-k-space (tt/tk)-generalized autocalibrating partially parallel acquisition (GRAPPA). A new multipurpose interleaved calibration scan (interleaved MUSICAL) acquires reference data for both coil combination and PI. This renders the reconstruction process (especially PI) less sensitive to instabilities. METHODS Six healthy volunteers were scanned at 7T. Three calibration datasets for coil combination and PI were recorded: a) iMUSICAL, b) static MUSICAL as prescan, c) moved MUSICAL as prescan with misaligned head position. The coil combination performance, including motion sensitivity, of iMUSICAL was compared to MUSICAL for single-slice free induction decay (FID)-MRSI. Through-time/through-k-space-GRAPPA with constant/variable-density undersampling was evaluated on the same data, comparing the three calibration datasets. Additionally, the proposed method was successfully applied to 3D whole-brain FID-MRSI. RESULTS Using iMUSICAL for coil combination yielded the highest signal-to-noise ratio (SNR) (+9%) and lowest Cramer-Rao lower bounds (CRLBs) (-6%) compared to both MUSICAL approaches, with similar metabolic map quality. Also, excellent mean g-factors of 1.07 and low residual lipid aliasing were obtained when using iMUSICAL as calibration data for two-fold, variable-density undersampling, while significantly degraded metabolic maps were obtained using the misaligned MUSICAL calibration data. CONCLUSION Through-time/through-k-space-GRAPPA can accelerate already time-efficient non-Cartesian spatial-spectral 2D/3D-MRSI encoding even further. Particularly promising results have been achieved using iMUSICAL as a robust, interleaved multipurpose calibration for MRSI reconstruction, without extra calibration prescan.
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Affiliation(s)
- Philipp Moser
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Lukas Hingerl
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Eva Heckova
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Gilbert Hangel
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Stanislav Motyka
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Bernhard Strasser
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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12
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Erturk MA, Li X, Van de Moortele PF, Ugurbil K, Metzger GJ. Evolution of UHF Body Imaging in the Human Torso at 7T: Technology, Applications, and Future Directions. Top Magn Reson Imaging 2019; 28:101-124. [PMID: 31188271 PMCID: PMC6587233 DOI: 10.1097/rmr.0000000000000202] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
The potential value of ultrahigh field (UHF) magnetic resonance imaging (MRI) and spectroscopy to biomedical research and in clinical applications drives the development of technologies to overcome its many challenges. The increased difficulties of imaging the human torso compared with the head include its overall size, the dimensions and location of its anatomic targets, the increased prevalence and magnitude of physiologic effects, the limited availability of tailored RF coils, and the necessary transmit chain hardware. Tackling these issues involves addressing notoriously inhomogeneous transmit B1 (B1) fields, limitations in peak B1, larger spatial variations of the static magnetic field B0, and patient safety issues related to implants and local RF power deposition. However, as research institutions and vendors continue to innovate, the potential gains are beginning to be realized. Solutions overcoming the unique challenges associated with imaging the human torso are reviewed as are current studies capitalizing on the benefits of UHF in several anatomies and applications. As the field progresses, strategies associated with the RF system architecture, calibration methods, RF pulse optimization, and power monitoring need to be further integrated into the MRI systems making what are currently complex processes more streamlined. Meanwhile, the UHF MRI community must seize the opportunity to build upon what have been so far proof of principle and feasibility studies and begin to further explore the true impact in both research and the clinic.
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Affiliation(s)
- M Arcan Erturk
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN
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13
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Cheong I, Deelchand DK, Eberly LE, Marjańska M, Manousakis G, Guliani G, Walk D, Öz G. Neurochemical correlates of functional decline in amyotrophic lateral sclerosis. J Neurol Neurosurg Psychiatry 2019; 90:294-301. [PMID: 30467209 PMCID: PMC6467050 DOI: 10.1136/jnnp-2018-318795] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/08/2018] [Accepted: 09/19/2018] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To determine whether proton magnetic resonance spectroscopy (1H-MRS) can detect neurochemical changes in amyotrophic lateral sclerosis (ALS) associated with heterogeneous functional decline. METHODS Nineteen participants with early-stage ALS and 18 age-matched and sex ratio-matched controls underwent ultra-high field 1H-MRS scans of the upper limb motor cortex and pons, ALS Functional Rating Scale-Revised (ALSFRS-R total, upper limb and bulbar) and upper motor neuron burden assessments in a longitudinal observational study design with follow-up assessments at 6 and 12 months. Slopes of neurochemical levels over time were compared between patient subgroups classified by the rate of upper limb or bulbar functional decline. 1H-MRS and clinical ratings at baseline were assessed for ability to predict study withdrawal due to disease progression. RESULTS Motor cortex total N-acetylaspartate to myo-inositol ratio (tNAA:mIns) significantly declined in patients who worsened in upper limb function over the follow-up period (n=9, p=0.002). Pons glutamate + glutamine significantly increased in patients who worsened in bulbar function (n=6, p<0.0001). Neurochemical levels did not change in patients with stable function (n=5-6) or in healthy controls (n=14-16) over time. Motor cortex tNAA:mIns and ALSFRS-R at baseline were significantly lower in patients who withdrew from follow-up due to disease progression (n=6) compared with patients who completed the 12-month scan (n=10) (p<0.001 for tNAA:mIns; p<0.01 for ALSFRS-R), with a substantially larger overlap in ALSFRS-R between groups. CONCLUSION Neurochemical changes in motor areas of the brain are associated with functional decline in corresponding body regions. 1H-MRS was a better predictor of study withdrawal due to ALS progression than ALSFRS-R.
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Affiliation(s)
- Ian Cheong
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, USA
| | - Dinesh K Deelchand
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, USA
| | - Lynn E Eberly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, USA
| | - Małgorzata Marjańska
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, USA
| | | | - Gaurav Guliani
- Hennepin County Medical Center and HealthPartners Neuroscience Center, Minneapolis, USA
| | - David Walk
- Department of Neurology, University of Minnesota, Minneapolis, USA
| | - Gülin Öz
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, USA
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14
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Reid MA, Salibi N, White DM, Gawne TJ, Denney TS, Lahti AC. 7T Proton Magnetic Resonance Spectroscopy of the Anterior Cingulate Cortex in First-Episode Schizophrenia. Schizophr Bull 2019; 45:180-189. [PMID: 29385594 PMCID: PMC6293230 DOI: 10.1093/schbul/sbx190] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recent magnetic resonance spectroscopy (MRS) studies suggest that abnormalities of the glutamatergic system in schizophrenia may be dependent on illness stage, medication status, and symptomatology. Glutamatergic metabolites appear to be elevated in the prodromal and early stages of schizophrenia but unchanged or reduced below normal in chronic, medicated patients. However, few of these studies have measured metabolites with high-field 7T MR scanners, which offer higher signal-to-noise ratio and better spectral resolution than 3T scanners and facilitate separation of glutamate and glutamine into distinct signals. In this study, we examined glutamate and other metabolites in the dorsal anterior cingulate cortex (ACC) of first-episode schizophrenia patients. Glutamate and N-acetylaspartate (NAA) were significantly lower in schizophrenia patients vs controls. No differences were observed in levels of glutamine, GABA, or other metabolites. In schizophrenia patients but not controls, GABA was negatively correlated with the total score on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) as well as the immediate memory and language subscales. Our findings suggest that glutamate and NAA reductions in the ACC may be present early in the illness, but additional large-scale studies are needed to confirm these results as well as longitudinal studies to determine the effect of illness progression and treatment. The correlation between GABA and cognitive function suggests that MRS may be an important technique for investigating the neurobiology underlying cognitive deficits in schizophrenia.
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Affiliation(s)
- Meredith A Reid
- AU MRI Research Center, Department of Electrical & Computer Engineering, Auburn University
| | | | - David M White
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham
| | - Timothy J Gawne
- Department of Vision Sciences, The University of Alabama at Birmingham
| | - Thomas S Denney
- AU MRI Research Center, Department of Electrical & Computer Engineering, Auburn University
| | - Adrienne C Lahti
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham,To whom correspondence should be addressed; Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham, SC 501, 1720 2 Ave S, Birmingham, AL 35294-0017, US; tel: 205-996-6776, fax: 205-975-4879, e-mail:
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15
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Shah P, Bassett DS, Wisse LE, Detre JA, Stein JM, Yushkevich PA, Shinohara RT, Pluta JB, Valenciano E, Daffner M, Wolk DA, Elliott MA, Litt B, Davis KA, Das SR. Mapping the structural and functional network architecture of the medial temporal lobe using 7T MRI. Hum Brain Mapp 2018; 39:851-865. [PMID: 29159960 PMCID: PMC5764800 DOI: 10.1002/hbm.23887] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/31/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
Medial temporal lobe (MTL) subregions play integral roles in memory function and are differentially affected in various neurological and psychiatric disorders. The ability to structurally and functionally characterize these subregions may be important to understanding MTL physiology and diagnosing diseases involving the MTL. In this study, we characterized network architecture of the MTL in healthy subjects (n = 31) using both resting state functional MRI and MTL-focused T2-weighted structural MRI at 7 tesla. Ten MTL subregions per hemisphere, including hippocampal subfields and cortical regions of the parahippocampal gyrus, were segmented for each subject using a multi-atlas algorithm. Both structural covariance matrices from correlations of subregion volumes across subjects, and functional connectivity matrices from correlations between subregion BOLD time series were generated. We found a moderate structural and strong functional inter-hemispheric symmetry. Several bilateral hippocampal subregions (CA1, dentate gyrus, and subiculum) emerged as functional network hubs. We also observed that the structural and functional networks naturally separated into two modules closely corresponding to (a) bilateral hippocampal formations, and (b) bilateral extra-hippocampal structures. Finally, we found a significant correlation in structural and functional connectivity (r = 0.25). Our findings represent a comprehensive analysis of network topology of the MTL at the subregion level. We share our data, methods, and findings as a reference for imaging methods and disease-based research.
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Affiliation(s)
- Preya Shah
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Center for Neuroengineering and TherapeuticsUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Danielle S. Bassett
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of Electrical & Systems EngineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Laura E.M. Wisse
- Penn Image Computing and Science LaboratoryUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - John A. Detre
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Center for Functional Neuroimaging, University of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Joel M. Stein
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Paul A. Yushkevich
- Penn Image Computing and Science LaboratoryUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Russell T. Shinohara
- Department of BiostatisticsEpidemiology and Informatics, University of PennsylvaniaPhiladelphiaPennsylvania19104
| | - John B. Pluta
- Penn Image Computing and Science LaboratoryUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Elijah Valenciano
- Penn Image Computing and Science LaboratoryUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Molly Daffner
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Penn Memory Center, University of PennsylvaniaPhiladelphiaPennsylvania19104
| | - David A. Wolk
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Penn Memory Center, University of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Mark A. Elliott
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Brian Litt
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Center for Neuroengineering and TherapeuticsUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Kathryn A. Davis
- Center for Neuroengineering and TherapeuticsUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Sandhitsu R. Das
- Penn Image Computing and Science LaboratoryUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
- Department of NeurologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
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Schmidt MA, Engelhorn T, Marxreiter F, Winkler J, Lang S, Kloska S, Goelitz P, Doerfler A. Ultra high-field SWI of the substantia nigra at 7T: reliability and consistency of the swallow-tail sign. BMC Neurol 2017; 17:194. [PMID: 29073886 PMCID: PMC5658950 DOI: 10.1186/s12883-017-0975-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 10/20/2017] [Indexed: 12/02/2022] Open
Abstract
Background The loss of the swallow-tail sign of the substantia nigra has been proposed for diagnosis of Parkinson’s disease. Aim was to evaluate, if the sign occurs consistently in healthy subjects and if it can be reliably detected with high-resolution 7T susceptibility weighted imaging (SWI). Methods Thirteen healthy adults received SWI at 7T. 3 neuroradiologists, who were blinded to patients’ diagnosis, independently classified subjects regarding the swallow-tail sign to be present or absent. Accuracy, positive and negative predictive values (PPV and NPV) as well as inter- and intra-rater reliability and internal consistency were analyzed. Results The sign could be detected in 81% of the cases in consensus reading. Accuracy to detect the sign compared to the consensus was 100, 77 and 96% for the three readers with PPV reader 1/2/3 = 1/0.45/0.83 and NPV = 1/1/1. Inter-rater reliability was excellent (inter-class correlation coefficient = 0.844, alpha = 0.871). Intra-rater reliability was good to excellent (reader 1 R/L = 0.625/0.786; reader 2 = 0.7/0.64; reader 3 = 0.9/1). Conclusion The swallow-tail sign can be reliably detected. However, our data suggest its occurrence is not consistent in healthy subjects. It may be possible that one reason is an individually variable molecular organization of nigrosome 1 so that it does not return a uniform signal in SWI.
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Affiliation(s)
- Manuel A Schmidt
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany.
| | - Tobias Engelhorn
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Franz Marxreiter
- Department of Molecular Neurology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Juergen Winkler
- Department of Molecular Neurology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Stefan Lang
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Stephan Kloska
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Philipp Goelitz
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Arnd Doerfler
- Department of Neuroradiology, University Hospital Erlangen-Nuremberg, Schwabachanlage 6, 91054, Erlangen, Germany
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17
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Wyss M, Duerst Y, Nanz D, Kasper L, Wilm BJ, Dietrich BE, Gross S, Schmid T, Brunner DO, Pruessmann KP. Feedback field control improves the precision of T 2 * quantification at 7 T. NMR Biomed 2017; 30:e3753. [PMID: 28678353 DOI: 10.1002/nbm.3753] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 04/10/2017] [Accepted: 05/04/2017] [Indexed: 06/07/2023]
Abstract
T2 * mapping offers access to a number of important structural and physiological tissue parameters. It is robust against RF field variations and overall signal scaling. However, T2 * measurement is highly sensitive to magnetic field errors, including perturbations caused by breathing motion at high baseline field. The goal of this work is to assess this issue in T2 * mapping of the brain and to study the benefit of field stabilization by feedback field control. T2 * quantification in the brain was investigated by phantom and in vivo measurements at 7 T. Repeated measurements were made with and without feedback field control using NMR field sensing and dynamic third-order shim actuation. The precision and reliability of T2 * quantification was assessed by studying variation across repeated measurements as well as fitting errors. Breathing effects were found to introduce significant error in T2 * mapping results. Field control mitigates this problem substantially. In a phantom it virtually eliminates the effects of emulated breathing fluctuations in the head. In vivo it enhances the structural fidelity of T2 * maps and reduces fitting residuals along with standard deviation. In conclusion, feedback field control improves the fidelity of T2 * mapping in the presence of field perturbations. It is an effective means of countering bulk susceptibility effects of breathing and hence holds particular promise for efforts to leverage high field for T2 * studies in vivo.
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Affiliation(s)
- Michael Wyss
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | - Yolanda Duerst
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | - Daniel Nanz
- University Hospital Zurich Institute of Diagnostic and Interventional Radiology, Zurich, Switzerland
| | - Lars Kasper
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
- University of Zurich and ETH Zurich Translational Neuromodeling Unit, Zurich, Switzerland
| | - Bertram Jakob Wilm
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | | | - Simon Gross
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | - Thomas Schmid
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | - David Otto Brunner
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
| | - Klaas Paul Pruessmann
- University of Zurich and ETH Zurich Institute for Biomedical Engineering, Zurich, Switzerland
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Clarke WT, Robson MD, Neubauer S, Rodgers CT. Creatine kinase rate constant in the human heart measured with 3D-localization at 7 tesla. Magn Reson Med 2016; 78:20-32. [PMID: 27579566 PMCID: PMC5484353 DOI: 10.1002/mrm.26357] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/26/2016] [Accepted: 07/06/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE We present a new Bloch-Siegert four Angle Saturation Transfer (BOAST) method for measuring the creatine kinase (CK) first-order effective rate constant kf in human myocardium at 7 tesla (T). BOAST combines a variant of the four-angle saturation transfer (FAST) method using amplitude-modulated radiofrequency pulses, phosphorus Bloch-Siegert B1+-mapping to determine the per-voxel flip angles, and nonlinear fitting to Bloch simulations for postprocessing. METHODS Optimal flip angles and repetition time parameters were determined from Monte Carlo simulations. BOAST was validated in the calf muscle of two volunteers at 3T and 7T. The myocardial CK forward rate constant was then measured in 10 volunteers at 7T in 82 min (after 1 H localization). RESULTS BOAST kfCK values were 0.281 ± 0.002 s-1 in the calf and 0.35 ± 0.05 s-1 in myocardium. These are consistent with literature values from lower fields. Using a literature values for adenosine triphosphate concentration, we computed CK flux values of 4.55 ± 1.52 mmol kg-1 s-1 . The sensitive volume for BOAST depends on the B1 inhomogeneity of the transmit coil. CONCLUSION BOAST enables measurement of the CK rate constant in the human heart at 7T, with spatial localization in three dimensions to 5.6 mL voxels, using a 10-cm loop coil. Magn Reson Med 78:20-32, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- William T Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Christopher T Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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Hahnemann ML, Kraff O, Maderwald S, Johst S, Orzada S, Umutlu L, Ladd ME, Quick HH, Lauenstein TC. Non-enhanced magnetic resonance imaging of the small bowel at 7 Tesla in comparison to 1.5 Tesla: First steps towards clinical application. Magn Reson Imaging 2015; 34:668-73. [PMID: 26747410 DOI: 10.1016/j.mri.2015.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/29/2015] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To perform non-enhanced (NE) magnetic resonance imaging (MRI) of the small bowel at 7 Tesla (7T) and to compare it with 1.5 Tesla (1.5T). MATERIAL AND METHODS Twelve healthy subjects were prospectively examined using a 1.5T and 7T MRI system. Coronal and axial true fast imaging with steady-state precession (TrueFISP) imaging and a coronal T2-weighted (T2w) half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence were acquired. Image analysis was performed by 1) visual evaluation of tissue contrast and detail detectability, 2) measurement and calculation of contrast ratios and 3) assessment of artifacts. RESULTS NE MRI of the small bowel at 7T was technically feasible. In the vast majority of the cases, tissue contrast and image details were equivalent at both field strengths. At 7T, two cases revealed better detail detectability in the TrueFISP, and better contrast in the HASTE. Susceptibility artifacts and B1 inhomogeneities were significantly increased at 7T. CONCLUSION This study provides first insights into NE ultra-high field MRI of the small bowel and may be considered an important step towards high quality T2w abdominal imaging at 7T MRI.
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Affiliation(s)
- Maria L Hahnemann
- Institute of Clinical Radiology, University Hospital Muenster, University of Muenster, Muenster, Germany; Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
| | - Oliver Kraff
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Soeren Johst
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Stephan Orzada
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
| | - Mark E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; High Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Thomas C Lauenstein
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
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20
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van der Kemp WJM, Wijnen JP, Luijten PR, Klomp DWJ. Saturation-transfer effects and longitudinal relaxation times of (31) P metabolites in fibroglandular breast tissue at 7T. Magn Reson Med 2015; 76:402-7. [PMID: 26418725 DOI: 10.1002/mrm.25871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/13/2015] [Accepted: 07/16/2015] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate longitudinal relaxation times and saturation-transfer effects of phosphorous metabolites in breast fibroglandular tissue in vivo with (31) P MR spectroscopy at 7T. METHODS Progressive saturation with adiabatic half passage excitation was used to determine T1 values of (31) P metabolites in a group of six healthy volunteers. Saturation-transfer experiments were performed in seven healthy volunteers by saturating at 0 ppm and 10 ppm with sinc-Gaussian pulses (90 ms; 10-ms pulse interval; B1 = 17 μT) prior to excitation. Localization was performed by surface coils and one-dimensional chemical shift imaging. Data were analyzed via spectral fitting with the JMRUI software package, and T1 values were obtained by fitting the data to the signal equation. RESULTS The determined longitudinal relaxation time values at 7T were as follows: phosphoethanolamine, 4.0 ± 0.2 s; phosphocholine, 1.8 ± 0.2 s; inorganic phosphate, 6.1 ± 0.1 s; phosphodiesters, glycerophosphatidylethanolamine plus glycerophosphocholine, 2.1 ± 0.1, and glycerophosphatidylethanolamine, 1.5 ± 0.1s; γ-ATP, 2.1 ± 0.1 s; and α-ATP, 2.0 ± 0.1 s. Saturation-transfer measurements with saturation pulses at 0 ppm showed a significant signal reduction in the phosphodiester 2-3 ppm range, whereas the γ-ATP signal at -2.5 ppm was not affected significantly. CONCLUSION Longitudinal relaxation times of phosphorous metabolites in fibroglandular tissue revealed relatively low T1 values for phosphodiesters. Saturation-transfer measurements showed that the phosphodiester signals were the only signals that were affected significantly, possibly indicating the presence of mobile phospholipids. Magn Reson Med 76:402-407, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Jannie P Wijnen
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
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21
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Chang G, Honig S, Liu Y, Chen C, Chu KK, Rajapakse CS, Egol K, Xia D, Saha PK, Regatte RR. 7 Tesla MRI of bone microarchitecture discriminates between women without and with fragility fractures who do not differ by bone mineral density. J Bone Miner Metab 2015; 33:285-93. [PMID: 24752823 PMCID: PMC4363287 DOI: 10.1007/s00774-014-0588-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 03/17/2014] [Indexed: 01/23/2023]
Abstract
Osteoporosis is a disease of poor bone quality. Bone mineral density (BMD) has limited ability to discriminate between subjects without and with poor bone quality, and assessment of bone microarchitecture may have added value in this regard. Our goals were to use 7 T MRI to: (1) quantify and compare distal femur bone microarchitecture in women without and with poor bone quality (defined clinically by presence of fragility fractures); and (2) determine whether microarchitectural parameters could be used to discriminate between these two groups. This study had institutional review board approval, and we obtained written informed consent from all subjects. We used a 28-channel knee coil to image the distal femur of 31 subjects with fragility fractures and 25 controls without fracture on a 7 T MRI scanner using a 3-D fast low angle shot sequence (0.234 mm × 0.234 mm × 1 mm, parallel imaging factor = 2, acquisition time = 7 min 9 s). We applied digital topological analysis to quantify parameters of bone microarchitecture. All subjects also underwent standard clinical BMD assessment in the hip and spine. Compared to controls, fracture cases demonstrated lower bone volume fraction and markers of trabecular number, plate-like structure, and plate-to-rod ratio, and higher markers of trabecular isolation, rod disruption, and network resorption (p < 0.05 for all). There were no differences in hip or spine BMD T-scores between groups (p > 0.05). In receiver-operating-characteristics analyses, microarchitectural parameters could discriminate cases and controls (AUC = 0.66-0.73, p < 0.05). Hip and spine BMD T-scores could not discriminate cases and controls (AUC = 0.58-0.64, p ≥ 0.08). We conclude that 7 T MRI can detect bone microarchitectural deterioration in women with fragility fractures who do not differ by BMD. Microarchitectural parameters might some day be used as an additional tool to detect patients with poor bone quality who cannot be detected by dual-energy X-ray absorptiometry (DXA).
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Affiliation(s)
- Gregory Chang
- Department of Radiology, NYU Langone Medical Center, Center for Musculoskeletal Care, 333 E. 38th Street, 6th Floor, Room 6-210, New York, NY, 10016, USA,
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Wisse LEM, Biessels GJ, Stegenga BT, Kooistra M, van der Veen PH, Zwanenburg JJM, van der Graaf Y, Geerlings MI. Major depressive episodes over the course of 7 years and hippocampal subfield volumes at 7 tesla MRI: the PREDICT-MR study. J Affect Disord 2015; 175:1-7. [PMID: 25589378 DOI: 10.1016/j.jad.2014.12.052] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Smaller hippocampal volumes have been associated with major depressive disorder (MDD). The hippocampus consists of several subfields that may be differentially related to MDD. We investigated the association of occurrence of major depressive episodes (MDEs), assessed five times over seven years, with hippocampal subfield and entorhinal cortex volumes at 7 tesla MRI. METHODS In this prospective study of randomly selected general practice attendees, MDEs according to DSM-IV-R criteria were assessed at baseline and after 6, 12, 39 and 84 months follow-up. At the last follow-up, a T2 (0.7 mm(3)) 7 tesla MRI scan was obtained in 47 participants (60±10 years). The subiculum, cornu ammonis (CA) 1 to 3, dentate gyrus&CA4 and entorhinal cortex volumes were manually segmented according a published protocol. RESULTS Of the 47 participants, 13 had one MDE and 5 had multiple MDEs. ANCOVAs, adjusted for age, sex, education and intracranial volume, revealed no significant differences in hippocampal subfield or entorhinal cortex volumes between participants with and without an MDE in the preceding 84 months. Multiple episodes were associated with smaller subiculum volumes (B=-0.03 mL/episode; 95% CI -0.06; -0.003), but not with the other hippocampal subfield volumes, entorhinal cortex, or total hippocampal volume. LIMITATIONS A limitation of this study is the small sample size which makes replication necessary. CONCLUSIONS In this exploratory study, we found that an increasing number of major depressive episodes was associated with smaller subiculum volumes in middle-aged and older persons, but not with smaller volumes in other hippocampal subfields or the entorhinal cortex.
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Affiliation(s)
- L E M Wisse
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands; Department of Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | - G J Biessels
- Department of Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | - B T Stegenga
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands
| | - M Kooistra
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands; Department of Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | - P H van der Veen
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands; Department of Radiology, UMC Utrecht, Utrecht, The Netherlands
| | | | - Y van der Graaf
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands
| | - M I Geerlings
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands.
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Yang S, Yang Z, Fischer K, Zhong K, Stadler J, Godenschweger F, Steiner J, Heinze HJ, Bernstein HG, Bogerts B, Mawrin C, Reutens DC, Speck O, Walter M. Integration of ultra-high field MRI and histology for connectome based research of brain disorders. Front Neuroanat 2013; 7:31. [PMID: 24098272 PMCID: PMC3784919 DOI: 10.3389/fnana.2013.00031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 09/09/2013] [Indexed: 11/13/2022] Open
Abstract
Ultra-high field magnetic resonance imaging (MRI) became increasingly relevant for in vivo neuroscientific research because of improved spatial resolutions. However, this is still the unchallenged domain of histological studies, which long played an important role in the investigation of neuropsychiatric disorders. While the field of biological psychiatry strongly advanced on macroscopic levels, current developments are rediscovering the richness of immunohistological information when attempting a multi-level systematic approach to brain function and dysfunction. For most studies, histology sections lost information on three-dimensional reconstructions. Translating histological sections to 3D-volumes would thus not only allow for multi-stain and multi-subject alignment in post mortem data, but also provide a crucial step in big data initiatives involving the network analyses currently performed with in vivo MRI. We therefore investigated potential pitfalls during integration of MR and histological information where no additional blockface information is available. We demonstrated that strengths and requirements from both methods can be effectively combined at a spatial resolution of 200 μm. However, the success of this approach is heavily dependent on choices of hardware, sequence and reconstruction. We provide a fully automated pipeline that optimizes histological 3D reconstructions, providing a potentially powerful solution not only for primary human post mortem research institutions in neuropsychiatric research, but also to help alleviate the massive workloads in neuroanatomical atlas initiatives. We further demonstrate (for the first time) the feasibility and quality of ultra-high spatial resolution (150 μm isotopic) imaging of the entire human brain MRI at 7T, offering new opportunities for analyses on MR-derived information.
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Affiliation(s)
- Shan Yang
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke University Magdeburg, Germany ; Leibniz Institute for Neurobiology Magdeburg, Germany
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Siero JC, Hermes D, Hoogduin H, Luijten PR, Petridou N, Ramsey NF. BOLD consistently matches electrophysiology in human sensorimotor cortex at increasing movement rates: a combined 7T fMRI and ECoG study on neurovascular coupling. J Cereb Blood Flow Metab 2013; 33:1448-56. [PMID: 23801242 DOI: 10.1038/jcbfm.2013.97] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/26/2013] [Accepted: 05/18/2013] [Indexed: 12/22/2022]
Abstract
Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used to measure human brain function and relies on the assumption that hemodynamic changes mirror the underlying neuronal activity. However, an often reported saturation of the BOLD response at high movement rates has led to the notion of a mismatch in neurovascular coupling. We combined BOLD fMRI at 7T and intracranial electrocorticography (ECoG) to assess the relationship between BOLD and neuronal population activity in human sensorimotor cortex using a motor task with increasing movement rates. Though linear models failed to predict BOLD responses from the task, the measured BOLD and ECoG responses from the same tissue were in good agreement. Electrocorticography explained almost 80% of the mismatch between measured- and model-predicted BOLD responses, indicating that in human sensorimotor cortex, a large portion of the BOLD nonlinearity with respect to behavior (movement rate) is well predicted by electrophysiology. The results further suggest that other reported examples of BOLD mismatch may be related to neuronal processes, rather than to neurovascular uncoupling.
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Zhu H, Soher BJ, Ouwerkerk R, Schär M, Barker PB. Spin-echo magnetic resonance spectroscopic imaging at 7 T with frequency-modulated refocusing pulses. Magn Reson Med 2013; 69:1217-25. [PMID: 22692894 PMCID: PMC3443531 DOI: 10.1002/mrm.24357] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 04/30/2012] [Accepted: 05/09/2012] [Indexed: 11/08/2022]
Abstract
Two approaches to high-resolution SENSE-encoded magnetic resonance spectroscopic imaging (MRSI) of the human brain at 7 Tesla (T) with whole-slice coverage are described. Both sequences use high-bandwidth radiofrequency pulses to reduce chemical shift displacement artifacts, SENSE-encoding to reduce scan time, and dual-band water and lipid suppression optimized for 7 T. Simultaneous B0 and transmit B1 mapping was also used for both sequences to optimize field homogeneity using high-order shimming and determine optimum radiofrequency transmit level, respectively. One sequence ("Hahn-MRSI") used reduced flip angle (90°) refocusing pulses for lower radiofrequency power deposition, while the other sequence used adiabatic fast passage refocusing pulses for improved sensitivity and reduced signal dependence on the transmit-B1 level. In four normal subjects, adiabatic fast passage-MRSI showed a signal-to-noise ratio improvement of 3.2±0.5 compared to Hahn-MRSI at the same spatial resolution, pulse repetition time, echo time, and SENSE-acceleration factor. An interleaved two-slice Hahn-MRSI sequence is also demonstrated to be experimentally feasible.
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Affiliation(s)
- He Zhu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| | - Brian J. Soher
- Duke University Medical Center, Department of Radiology, DUMC Box 3808, Durham, NC 27710
| | - Ronald Ouwerkerk
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | | | - Peter B. Barker
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
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Chang G, Rajapakse CS, Diamond M, Honig S, Recht MP, Weiss DS, Regatte RR. Micro-finite element analysis applied to high-resolution MRI reveals improved bone mechanical competence in the distal femur of female pre-professional dancers. Osteoporos Int 2013; 24:1407-17. [PMID: 22893356 PMCID: PMC3719856 DOI: 10.1007/s00198-012-2105-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/10/2012] [Indexed: 02/07/2023]
Abstract
UNLABELLED Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation. INTRODUCTION The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls. METHODS This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups. RESULTS Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p<0.05). Cortical bone stiffness, cross-sectional area, and thickness did not differ between groups (>0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p<0.05). Adjustment for cancellous bone cross-sectional area eliminated significant differences in whole bone stiffness between groups (p>0.07), but adjustment for cortical bone cross-sectional area did not (p<0.03). CONCLUSIONS Modern dancers have greater whole and cancellous bone stiffness in the distal femur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.
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Affiliation(s)
- G Chang
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, NYU Langone Medical Center, 660 First Avenue, 2nd Floor, New York, NY 10016, USA.
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Moheet A, Emir UE, Terpstra M, Kumar A, Eberly LE, Seaquist ER, Öz G. Initial experience with seven tesla magnetic resonance spectroscopy of hypothalamic GABA during hyperinsulinemic euglycemia and hypoglycemia in healthy humans. Magn Reson Med 2013; 71:12-8. [PMID: 23423963 DOI: 10.1002/mrm.24663] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 01/07/2013] [Accepted: 01/08/2013] [Indexed: 12/30/2022]
Abstract
PURPOSE Hypothalamic GABA signaling has been shown to regulate the hormonal response to hypoglycemia in animals. The hypothalamus is a challenging brain region for magnetic resonance spectroscopy (MRS) due to its small size and central location. To investigate the feasibility of measuring GABA in the hypothalamus in humans, ultra-high field MRS was used. METHODS GABA levels in the hypothalamus and occipital cortex (control region) were measured in healthy volunteers during euglycemia and hypoglycemia at 7 tesla using short-echo STEAM (TE = 8 ms, TR = 5 s). RESULTS Hypothalamic GABA levels were quantified with a mean within-session test-retest coefficient of variance of 9%. Relatively high GABA levels were observed in the hypothalamus compared with other brain regions. Hypothalamic GABA levels were 3.5 ± 0.3 µmol/g during euglycemia (glucose 89 ± 6 mg/dL) vs. 3.0 ± 0.4 µmol/g during hypoglycemia (glucose 61 ± 3 mg/dL) (P = 0.06, N = 7). In the occipital cortex, GABA levels remained constant at 1.4 ± 0.4 vs.1.4 ± 0.3 µmol/g (P = 0.3, N = 5) as glucose fell from 91 ± 4 to 61 ± 4 mg/dL. CONCLUSION GABA concentration can be quantified in the human hypothalamus and shows a trend toward decrease in response to an acute fall in blood glucose. These methods can be used to further investigate role of GABA signaling in the counterregulatory response to hypoglycemia in humans.
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Affiliation(s)
- A Moheet
- Department of Medicine, Division of Endocrinology and Diabetes, University of Minnesota, Minneapolis, Minnesota, USA
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Abstract
BACKGROUND We previously described two dynamics of contrast enhancement in scans of active multiple sclerosis lesions: Medium-sized, early lesions enhance centrifugally, whereas larger, slightly older lesions enhance centripetally. Due to technical limitations, our previous study did not characterize lesions < 5 mm in diameter, cortical enhancement, and anatomical structures within lesions. OBJECTIVE The objective of this paper is to obtain initial observations of these important aspects of lesion development on a 7 tesla scanner at high spatial resolution. METHODS We scanned eight patients, acquiring precontrast T2*-weighted scans, T1-weighted scans before and after contrast, and high-resolution dynamic contrast-enhanced scans during and up to 30 min after contrast. RESULTS We detected 15 enhancing lesions, obtaining dynamic data in 10: Five lesions < 4 mm enhanced centrifugally (initial central enhancement expanded outward), and five lesions > 4 mm enhanced centripetally (initial peripheral enhancement gradually filled the lesion). A leukocortical lesion initially showed enhancement in its white matter portion, which gradually spread into the cortex. Seventy-three percent of lesions were clearly perivenular. CONCLUSION Most active lesions are perivenular, and the smallest lesions enhance centrifugally. This supports the idea that lesions grow outward from a central vein.
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Affiliation(s)
- María I Gaitán
- Translational Neuroradiology Unit, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Cai K, Nanga RPR, Lamprou L, Schinstine C, Elliott M, Hariharan H, Reddy R, Epperson CN. The impact of gabapentin administration on brain GABA and glutamate concentrations: a 7T ¹H-MRS study. Neuropsychopharmacology 2012; 37:2764-71. [PMID: 22871916 PMCID: PMC3499716 DOI: 10.1038/npp.2012.142] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Gamma-aminobutyric acid (GABA) and glutamate are implicated in numerous neuropsychiatric and substance abuse conditions, but their spectral overlap with other resonances makes them a challenge to quantify in humans. Gabapentin, marketed for the treatment of seizures and neuropathic pain, has been shown to increase in vivo GABA concentration in the brain of both rodents and humans. Gabapentin effects on glutamate are not known. We conducted a gabapentin (900 mg) challenge in healthy human subjects to confirm and explore its effects on GABA and glutamate concentrations, respectively, and to test the ability of single voxel localized proton magnetic resonance spectroscopy (¹H-MRS) to reliably measure GABA and glutamate in the visual cortex at the ultra-high magnetic field of 7 Tesla. Reproducibility of GABA and glutamate measurements was determined in a comparison group without drug twice within day and 2 weeks apart. Although GABA concentration changes were small both within day (average 5.6%) and between day (average 4.8%), gabapentin administration was associated with an average increase in GABA concentration of 55.7% (6.9-91.0%). Importantly, drug-induced change in GABA levels was inversely correlated to the individual's baseline GABA level (R²=0.72). Mean glutamate concentrations did not change significantly with or without drug administration. In conclusion, localized ¹H-MRS at 7 Tesla can be successfully applied to the measurement of GABA concentration and is sensitive to acute drug-induced changes in cortical GABA. Whether baseline GABA concentrations predict clinical efficacy of gabapentin is an area worthy of exploration.
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Affiliation(s)
- Kejia Cai
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi PR Nanga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa Lamprou
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Claudia Schinstine
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Elliott
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - C Neill Epperson
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Penn Center for Women's Behavioral Wellness, 3535 Market Street, Room 3001, Philadelphia, PA 19104, USA, Tel: +1 215 573-8871, Fax: +1 215 573 8881, E-mail:
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Martuzzi R, van der Zwaag W, Farthouat J, Gruetter R, Blanke O. Human finger somatotopy in areas 3b, 1, and 2: a 7T fMRI study using a natural stimulus. Hum Brain Mapp 2012; 35:213-26. [PMID: 22965769 DOI: 10.1002/hbm.22172] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/23/2011] [Accepted: 07/10/2012] [Indexed: 11/07/2022] Open
Abstract
To study the properties of human primary somatosensory (S1) cortex as well as its role in cognitive and social processes, it is necessary to noninvasively localize the cortical representations of the body. Being arguably the most relevant body parts for tactile exploration, cortical representations of fingers are of particular interest. The aim of the present study was to investigate the cortical representation of individual fingers (D1-D5), using human touch as a stimulus. Utilizing the high BOLD sensitivity and spatial resolution at 7T, we found that each finger is represented within three subregions of S1 in the postcentral gyrus. Within each of these three areas, the fingers are sequentially organized (from D1 to D5) in a somatotopic manner. Therefore, these finger representations likely reflect distinct activations of BAs 3b, 1, and 2, similar to those described in electrophysiological work in non-human primates. Quantitative analysis of the local BOLD responses revealed that within BA3b, each finger representation is specific to its own stimulation without any cross-finger responsiveness. This finger response selectivity was less prominent in BA 1 and in BA 2. A test-retest procedure highlighted the reproducibility of the results and the robustness of the method for BA 3b. Finally, the representation of the thumb was enlarged compared to the other fingers within BAs 1 and 2. These findings extend previous human electrophysiological and neuroimaging data but also reveal differences in the functional organization of S1 in human and nonhuman primates.
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Affiliation(s)
- Roberto Martuzzi
- Laboratory of Cognitive Neuroscience, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Center for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Abstract
The opportunity to explore the human connectome using cutting-edge neuroimaging methods has elicited widespread interest. How far will the field be able to progress in deciphering long-distance connectivity patterns and in relating differences in connectivity to phenotypic characteristics in health and disease? We discuss the daunting nature of this challenge in relation to specific complexities of brain circuitry and known limitations of in vivo imaging methods. We also discuss the excellent prospects for continuing improvements in data acquisition and analysis. Accordingly, we are optimistic that major insights will emerge from human connectomics in the coming decade.
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Affiliation(s)
- D C Van Essen
- Washington University School of Medicine, Anatomy & Neurobiology, 660 S Euclid Avenue, St Louis, MO 63110, USA.
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Barry RL, Strother SC, Gore JC. Complex and magnitude-only preprocessing of 2D and 3D BOLD fMRI data at 7 T. Magn Reson Med 2012; 67:867-71. [PMID: 21748797 PMCID: PMC3193895 DOI: 10.1002/mrm.23072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 06/01/2011] [Accepted: 06/07/2011] [Indexed: 01/12/2023]
Abstract
A challenge to ultra high field functional magnetic resonance imaging is the predominance of noise associated with physiological processes unrelated to tasks of interest. This degradation in data quality may be partially reversed using a series of preprocessing algorithms designed to retrospectively estimate and remove the effects of these noise sources. However, such algorithms are routinely validated only in isolation, and thus consideration of their efficacies within realistic preprocessing pipelines and on different data sets is often overlooked. We investigate the application of eight possible combinations of three pseudo-complementary preprocessing algorithms - phase regression, Stockwell transform filtering, and retrospective image correction - to suppress physiological noise in 2D and 3D functional data at 7 T. The performance of each preprocessing pipeline was evaluated using data-driven metrics of reproducibility and prediction. The optimal preprocessing pipeline for both 2D and 3D functional data included phase regression, Stockwell transform filtering, and retrospective image correction. This result supports the hypothesis that a complex preprocessing pipeline is preferable to a magnitude-only pipeline, and suggests that functional magnetic resonance imaging studies should retain complex images and externally monitor subjects' respiratory and cardiac cycles so that these supplementary data may be used to retrospectively reduce noise and enhance overall data quality.
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Affiliation(s)
- Robert L Barry
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee 37232-2310, USA.
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Suttie JJ, Delabarre L, Pitcher A, van de Moortele PF, Dass S, Snyder CJ, Francis JM, Metzger GJ, Weale P, Ugurbil K, Neubauer S, Robson M, Vaughan T. 7 Tesla (T) human cardiovascular magnetic resonance imaging using FLASH and SSFP to assess cardiac function: validation against 1.5 T and 3 T. NMR Biomed 2012; 25:27-34. [PMID: 21774009 PMCID: PMC3440016 DOI: 10.1002/nbm.1708] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 12/02/2010] [Accepted: 02/15/2011] [Indexed: 05/04/2023]
Abstract
We report the first comparison of cardiovascular magnetic resonance imaging (CMR) at 1.5 T, 3 T and 7 T field strengths using steady state free precession (SSFP) and fast low angle shot (FLASH) cine sequences. Cardiac volumes and mass measurements were assessed for feasibility, reproducibility and validity at each given field strength using FLASH and SSFP sequences. Ten healthy volunteers underwent retrospectively electrocardiogram (ECG) gated CMR at 1.5 T, 3 T and 7 T using FLASH and SSFP sequences. B1 and B0 shimming and frequency scouts were used to optimise image quality. Cardiac volume and mass measurements were not significantly affected by field strength when using the same imaging sequence (P > 0.05 for all parameters at 1.5 T, 3 T and 7 T). SSFP imaging returned larger end diastolic and end systolic volumes and smaller left ventricular masses than FLASH imaging at 7 T, and at the lower field strengths (P < 0.05 for each parameter). However, univariate general linear model analysis with fixed effects for sequence and field strengths found an interaction between imaging sequence and field strength (P = 0.03), with a smaller difference in volumes and mass measurements between SSFP and FLASH imaging at 7 T than 1.5 T and 3 T. SSFP and FLASH cine imaging at 7 T is technically feasible and provides valid assessment of cardiac volumes and mass compared with CMR imaging at 1.5 T and 3 T field strengths.
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Affiliation(s)
- J J Suttie
- Department of Cardiovascular Medicine, University of Oxford, Centre for Clinical Magnetic Resonance Research, Oxford, UK.
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Ramadan S, Ratai EM, Wald LL, Mountford CE. In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T. J Magn Reson 2010; 204:91-8. [PMID: 20206561 PMCID: PMC3741347 DOI: 10.1016/j.jmr.2010.02.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 01/07/2010] [Accepted: 02/09/2010] [Indexed: 05/14/2023]
Abstract
AIM This study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation. METHOD Six healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28cm diameter detunable birdcage coil for signal excitation and an 8.5cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the 'progressive saturation' method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4ms increment size) and eight averages per scan, with a total time of 17min. RESULTS T1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20-0.26ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method. CONCLUSION In vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers.
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Affiliation(s)
- Saadallah Ramadan
- Centre for Clinical Spectroscopy, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 4 Blackfan St., H.I.M., 8th Floor, Boston, MA 02115, USA.
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