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Feng Y, Huang X, Zhao W, Ming Y, Zhou Y, Feng R, Xiao J, Shan X, Kang X, Duan X, Chen H. Association among internalizing problems, white matter integrity, and social difficulties in children with autism spectrum disorder. Prog Neuropsychopharmacol Biol Psychiatry 2024; 135:111109. [PMID: 39074528 DOI: 10.1016/j.pnpbp.2024.111109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/04/2024] [Accepted: 07/24/2024] [Indexed: 07/31/2024]
Abstract
Autism spectrum disorder (ASD) is characterized by social difficulties and often accompanied by internalizing and externalizing problems, which are frequently overlooked. Here, we examined and compared fractional anisotropy (FA) between 79 children with ASD (aged 4-7.8 years) and 70 age-, gender-, and handedness- matched typically developing controls (TDCs, aged 3-7.2 years). We aimed to explore the relationship among social difficulties, internalizing and externalizing problems, and brain structural foundation (characterized by white matter integrity). Compared with the TDCs, the children with ASD exhibited more severe internalizing and externalizing problems, which were positively correlated with social difficulties. Reduced FA values were observed in specific white matter tracts that integrate a fronto-temporal-occipital circuit. In particular, the FA values within this circuit were negatively correlated with internalizing problems and SRS-TOTAL scores. Mediation analysis revealed that internalizing problems mediated the relationship between the FA values in the left middle longitudinal fasciculus (L-MdLF) and corpus callosum forceps major (CCM) and social difficulties in children with ASD. These findings contribute to our understanding of social difficulties, internalizing and externalizing problems, and white matter integrity in children with ASD and highlight internalizing problems as a mediator between social difficulties and white matter integrity.
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Affiliation(s)
- Yu Feng
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Xinyue Huang
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Weixin Zhao
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Yating Ming
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Yuanyue Zhou
- Department of Medical Psychology, The First Affiliated Hospital, Hainan Medical University, Haikou 571199, Hainan, PR China
| | - Rui Feng
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Jinming Xiao
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Xiaolong Shan
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China
| | - Xiaodong Kang
- Child Rehabilitation Unit, Affiliated Sichuan Provincial Rehabilitation Hospital of Chengdu University of TCM, Sichuan, Bayi Rehabilitation Center, Chengdu 611135, PR China
| | - Xujun Duan
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China.
| | - Huafu Chen
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, PR China; MOE Key Lab for Neuro information, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, PR China.
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Middione MJ, Loecher M, Cao X, Setsompop K, Ennis DB. Pre-excitation gradients for eddy current nulled convex optimized diffusion encoding (Pre-ENCODE). Magn Reson Med 2024; 92:573-585. [PMID: 38501914 PMCID: PMC11142872 DOI: 10.1002/mrm.30068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
PURPOSE To evaluate the use of pre-excitation gradients for eddy current-nulled convex optimized diffusion encoding (Pre-ENCODE) to mitigate eddy current-induced image distortions in diffusion-weighted MRI (DWI). METHODS DWI sequences using monopolar (MONO), ENCODE, and Pre-ENCODE were evaluated in terms of the minimum achievable echo time (TE min $$ {}_{\mathrm{min}} $$ ) and eddy current-induced image distortions using simulations, phantom experiments, and in vivo DWI in volunteers (N = 6 $$ N=6 $$ ). RESULTS Pre-ENCODE provided a shorter TE min $$ {}_{\mathrm{min}} $$ than MONO (71.0± $$ \pm $$ 17.7ms vs. 77.6± $$ \pm $$ 22.9ms) and ENCODE (71.0± $$ \pm $$ 17.7ms vs. 86.2± $$ \pm $$ 14.2ms) in 100% $$ \% $$ of the simulated cases for a commercial 3T MRI system with b-values ranging from 500 to 3000 s/mm 2 $$ {}^2 $$ and in-plane spatial resolutions ranging from 1.0 to 3.0mm 2 $$ {}^2 $$ . Image distortion was estimated by intravoxel signal variance between diffusion encoding directions near the phantom edges and was significantly lower with Pre-ENCODE than with MONO (10.1% $$ \% $$ vs. 22.7% $$ \% $$ ,p = 6 - 5 $$ p={6}^{-5} $$ ) and comparable to ENCODE (10.1% $$ \% $$ vs. 10.4% $$ \% $$ ,p = 0 . 12 $$ p=0.12 $$ ). In vivo measurements of apparent diffusion coefficients were similar in global brain pixels (0.37 [0.28,1.45]× 1 0 - 3 $$ \times 1{0}^{-3} $$ mm 2 $$ {}^2 $$ /s vs. 0.38 [0.28,1.45]× 1 0 - 3 $$ \times 1{0}^{-3} $$ mm 2 $$ {}^2 $$ /s,p = 0 . 25 $$ p=0.25 $$ ) and increased in edge brain pixels (0.80 [0.17,1.49]× 1 0 - 3 $$ \times 1{0}^{-3} $$ mm 2 $$ {}^2 $$ /s vs. 0.70 [0.18,1.48]× 1 0 - 3 $$ \times 1{0}^{-3} $$ mm 2 $$ {}^2 $$ /s,p = 0 . 02 $$ p=0.02 $$ ) for MONO compared to Pre-ENCODE. CONCLUSION Pre-ENCODE mitigated eddy current-induced image distortions for diffusion imaging with a shorter TE min $$ {}_{\mathrm{min}} $$ than MONO and ENCODE.
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Affiliation(s)
| | - Michael Loecher
- Department of Radiology, Stanford University, Stanford, California
| | - Xiaozhi Cao
- Department of Radiology, Stanford University, Stanford, California
| | - Kawin Setsompop
- Department of Radiology, Stanford University, Stanford, California
- Department of Electrical Engineering, Stanford University, Stanford, California
| | - Daniel B Ennis
- Department of Radiology, Stanford University, Stanford, California
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Hamzehpour L, Bohn T, Dutsch V, Jaspers L, Grimm O. From brain to body: exploring the connection between altered reward processing and physical fitness in schizophrenia. Psychiatry Res 2024; 335:115877. [PMID: 38555826 DOI: 10.1016/j.psychres.2024.115877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/11/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
Understanding the underlying mechanisms that link psychopathology and physical comorbidities in schizophrenia is crucial since decreased physical fitness and overweight pose major risk factors for cardio-vascular diseases and decrease the patients' life expectancies. We hypothesize that altered reward anticipation plays an important role in this. We implemented the Monetary Incentive Delay task in a MR scanner and a fitness test battery to compare schizophrenia patients (SZ, n = 43) with sex- and age-matched healthy controls (HC, n = 36) as to reward processing and their physical fitness. We found differences in reward anticipation between SZs and HCs, whereby increased activity in HCs positively correlated with overall physical condition and negatively correlated with psychopathology. On the other handy, SZs revealed stronger activity in the posterior cingulate cortex and in cerebellar regions during reward anticipation, which could be linked to decreased overall physical fitness. These findings demonstrate that a dysregulated reward system is not only responsible for the symptomatology of schizophrenia, but might also be involved in physical comorbidities which could pave the way for future lifestyle therapy interventions.
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Affiliation(s)
- Lara Hamzehpour
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10 60528 Frankfurt am Main, Germany; Goethe University Frankfurt, Faculty 15 Biological Sciences, Frankfurt am Main, Germany.
| | - Tamara Bohn
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10 60528 Frankfurt am Main, Germany
| | - Valentin Dutsch
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10 60528 Frankfurt am Main, Germany
| | - Lucia Jaspers
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10 60528 Frankfurt am Main, Germany
| | - Oliver Grimm
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10 60528 Frankfurt am Main, Germany
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Hamzehpour L, Bohn T, Jaspers L, Grimm O. Exploring the link between functional connectivity of ventral tegmental area and physical fitness in schizophrenia and healthy controls. Eur Neuropsychopharmacol 2023; 76:77-86. [PMID: 37562082 DOI: 10.1016/j.euroneuro.2023.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 08/12/2023]
Abstract
Decreased physical fitness and being overweight are highly prevalent in schizophrenia, represent a major risk factor for comorbid cardio-vascular diseases and decrease the life expectancy of the patients. Thus, it is important to understand the underlying mechanisms that link psychopathology and weight gain. We hypothesize that the dopaminergic reward system plays an important role in this. We analyzed the seed-based functional connectivity (FC) of the ventral tegmental area (VTA) in a group of schizophrenic patients (n=32) and age-, as well as gender-, matched healthy controls (n=27). We then correlated the resting-state results with physical fitness parameters, obtained in a fitness test, and psychopathology. The FC analysis revealed decreased functional connections between the VTA and the anterior cingulate cortex (ACC), as well as the dorsolateral prefrontal cortex, which negatively correlated with psychopathology, and increased FC between the VTA and the middle temporal gyrus in patients compared to healthy controls, which positively correlated with psychopathology. The decreased FC between the VTA and the ACC of the patient group further positively correlated with total body fat (p = .018, FDR-corr.) and negatively correlated with the overall physical fitness (p = .022). This study indicates a link between decreased physical fitness and higher body fat with functional dysconnectivity between the VTA and the ACC. These findings demonstrate that a dysregulated reward system might also be involved in comorbidities and could pave the way for future lifestyle therapy interventions.
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Affiliation(s)
- Lara Hamzehpour
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany; Goethe University Frankfurt, Faculty 15 Biological Sciences, Frankfurt am Main, Germany.
| | - Tamara Bohn
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany
| | - Lucia Jaspers
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany
| | - Oliver Grimm
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany
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Steidl E, Rauch M, Hattingen E, Breuer S, Schüre JR, Grapengeter M, Shrestha M, Foerch C, Schaller-Paule MA. Qualitative and quantitative detectability of hypertrophic olivary degeneration in T2, FLAIR, PD, and DTI: A prospective MRI study. Front Neurol 2022; 13:950191. [PMID: 35989923 PMCID: PMC9381965 DOI: 10.3389/fneur.2022.950191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: Hypertrophic olivary degeneration (HOD) is a pathology of the inferior olivary nucleus (ION) that occurs after injuries to the Guillain-Mollaret triangle (GMT). Lacking a diagnostic gold standard, diagnosis is usually based on T2 or FLAIR imaging and expert rating. To facilitate precise HOD diagnosis in future studies, we assessed the reliability of this rater-based approach and explored alternative, quantitative analysis. Methods Patients who had suffered strokes in the GMT and a matched control group prospectively underwent an MRI examination including T2, FLAIR, and proton density (PD). Diffusion tensor imaging (DTI) was additionally performed in the patient group. The presence of HOD was assessed on FLAIR, T2, and PD separately by 3 blinded reviewers. Employing an easily reproducible segmentation approach, relative differences in intensity, fractional anisotropy (FA), and mean diffusivity (MD) between both IONs were calculated. Results In total, 15 patients were included in this study. The interrater reliability was best for FLAIR, followed by T2 and PD (Fleiss κ = 0.87 / 0.77 / 0.65). The 3 raters diagnosed HOD in 38–46% (FLAIR), 40–47% (T2), and 53–67% (PD) of patients. False-positive findings in the control group were less frequent in T2 than in PD and FLAIR (2.2% / 8.9% / 6.7%). In 53% of patients, the intensity difference between both IONs on PD was significantly increased in comparison with the control group. These patients also showed significantly decreased FA and increased MD. Conclusion While the rater-based approach yielded the best performance on T2 imaging, a quantitative, more sensitive HOD diagnosis based on ION intensities in PD and DTI imaging seems possible.
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Affiliation(s)
- Eike Steidl
- Institute of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Maximilian Rauch
- Institute of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Elke Hattingen
- Institute of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Stella Breuer
- Institute of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Jan Rüdiger Schüre
- Institute of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Marike Grapengeter
- Brain Imaging Center (BIC), Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Manoj Shrestha
- Department of Neurology, University Hospital Frankfurt, Goethe-University, Frankfurt am Main, Germany
| | - Christian Foerch
- Brain Imaging Center (BIC), Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Martin A. Schaller-Paule
- Brain Imaging Center (BIC), Goethe-University Frankfurt, Frankfurt am Main, Germany
- *Correspondence: Martin A. Schaller-Paule
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Loecher M, Middione MJ, Ennis DB. A gradient optimization toolbox for general purpose time-optimal MRI gradient waveform design. Magn Reson Med 2020; 84:3234-3245. [PMID: 33463724 PMCID: PMC7540314 DOI: 10.1002/mrm.28384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 01/16/2023]
Abstract
Purpose To introduce and demonstrate a software library for time‐optimal gradient waveform optimization with a wide range of applications. The software enables direct on‐the‐fly gradient waveform design on the scanner hardware for multiple vendors. Methods The open‐source gradient optimization (GrOpt) toolbox was implemented in C with both Matlab and Python wrappers. The toolbox enables gradient waveforms to be generated based on a set of constraints that define the features and encodings for a given acquisition. The GrOpt optimization routine is based on the alternating direction method of multipliers (ADMM). Additional constraints enable error corrections to be added, or patient comfort and safety to be adressed. A range of applications and compute speed metrics are analyzed. Finally, the method is implemented and tested on scanners from different vendors. Results Time‐optimal gradient waveforms for different pulse sequences and the constraints that define them are shown. Additionally, the ability to add, arbitrary motion (gradient moment) compensation or limit peripheral nerve stimulation is demonstrated. There exists a trade‐off between computation time and gradient raster time, but it was observed that acceptable gradient waveforms could be generated in 1‐40 ms. Gradient waveforms generated and run on the different scanners were functionally equivalent, and the images were comparable. Conclusions GrOpt is an open source toolbox that enables on‐the‐fly optimization of gradient waveform design, subject to a set of defined constraints. GrOpt was presented for a range of imaging applications, analyzed in terms of computational complexity, and implemented to run on the scanner for a multi‐vendor demonstration.
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Affiliation(s)
- Michael Loecher
- Department of Radiology, Stanford University, Stanford, CA, USA.,Department of Radiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Matthew J Middione
- Department of Radiology, Stanford University, Stanford, CA, USA.,Department of Radiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Daniel B Ennis
- Department of Radiology, Stanford University, Stanford, CA, USA.,Department of Radiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
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Middione MJ, Loecher M, Moulin K, Ennis DB. Optimization methods for magnetic resonance imaging gradient waveform design. NMR IN BIOMEDICINE 2020; 33:e4308. [PMID: 32342560 PMCID: PMC7606655 DOI: 10.1002/nbm.4308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 02/07/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
The development and implementation of novel MRI pulse sequences remains challenging and laborious. Gradient waveforms are typically designed using a combination of analytical and ad hoc methods to construct each gradient waveform axis independently. This strategy makes coding the pulse sequence complicated, in addition to being time inefficient. As a consequence, nearly all commercial MRI pulse sequences fail to maximize use of the available gradient hardware or efficiently mitigate physiological effects. This results in expensive MRI systems that underperform relative to their inherent hardware capabilities. To address this problem, a software solution is proposed that incorporates numerical optimization methods into MRI pulse sequence programming. Examples are shown for rotational variant vs. invariant waveform designs, acceleration nulled velocity encoding gradients, and mitigation of peripheral nerve stimulation for diffusion encoding. The application of optimization methods to MRI pulse sequence design incorporates gradient hardware limits and the prescribed MRI protocol parameters (e.g. field-of-view, resolution, gradient moments, and/or b-value) to simultaneously construct time-optimal gradient waveforms. In many cases, the resulting constrained gradient waveform design problem is convex and can be solved on-the-fly on the MRI scanner. The result is a set of multi-axis time-optimal gradient waveforms that satisfy the design constraints, thereby increasing SNR-efficiency. These optimization methods can also be used to mitigate imaging artifacts (e.g. eddy currents) or account for peripheral nerve stimulation. The result of the optimization method is to enable easier pulse sequence gradient waveform design and permit on-the-fly implementation for a range of MRI pulse sequences.
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Affiliation(s)
| | - Michael Loecher
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Kévin Moulin
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Daniel B. Ennis
- Department of Radiology, Stanford University, Stanford, CA, USA
- Department of Radiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
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Shrestha M, Lee HS, Nöth U, Deichmann R. A novel sequence to improve auditory functional MRI with variable silent delays. Magn Reson Med 2020; 85:883-896. [PMID: 32886374 DOI: 10.1002/mrm.28479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 11/09/2022]
Abstract
PURPOSE Auditory functional MRI (fMRI) often uses silent inter-volume delays for stimulus presentation. However, maintaining the steady-state of the magnetization usually requires constant delays. Here, a novel acquisition scheme dubbed "pre-Saturated EPI using Multiple delays in Steady-state" (SEPIMS) is proposed, using spin saturation at a fixed delay before each volume to maintain steady-state conditions, independent of previous spin history. This concept allows for variable inter-volume delays and thus for flexible stimulus design in auditory fMRI. The purpose was to compare the signal stability of SEPIMS and conventional sparse EPI (CS-EPI). METHODS The saturation module comprises two non-selective adiabatic saturation pulses. The efficiency of the saturation and its effect on the SEPIMS signal stability is tested in vitro and in vivo. RESULTS Data show that SEPIMS yields the same signal stability as CS-EPI, even for extreme variations between inter-volume delay durations. However, dual saturation pulses are required to achieve sufficiently high saturation efficiency in compartments with long T1 values. Importantly, spoiler gradient pulses after the EPI readout have to be optimized to avoid eddy-current-induced image distortions. CONCLUSION The proposed SEPIMS sequence maintains high signal stability in the presence of variable inter-volume durations, thus allowing for flexible stimulus design.
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Affiliation(s)
- Manoj Shrestha
- Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - H Sean Lee
- Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany
| | - Ulrike Nöth
- Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ralf Deichmann
- Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany
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Stock B, Shrestha M, Seiler A, Foerch C, Hattingen E, Steinmetz H, Deichmann R, Wagner M, Gracien RM. Distribution of Cortical Diffusion Tensor Imaging Changes in Multiple Sclerosis. Front Physiol 2020; 11:116. [PMID: 32231581 PMCID: PMC7083109 DOI: 10.3389/fphys.2020.00116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/31/2020] [Indexed: 11/13/2022] Open
Abstract
Purpose Diffuse cortical damage in relapsing–remitting multiple sclerosis (RRMS) is clinically relevant but cannot be directly assessed with conventional MRI. In this study, it was aimed to use diffusion tensor imaging (DTI) techniques with optimized intrinsic eddy current compensation to quantify and characterize cortical mean diffusivity (MD) and fractional anisotropy (FA) changes in RRMS and to analyze the distribution of these changes across the cortex. Materials and Methods Three-Tesla MRI acquisition, mapping of the MD providing information about the integrity of microstructural barriers and of the FA reflecting axonal density and surface-based analysis with Freesurfer were performed for 24 RRMS patients and 25 control subjects. Results Across the whole cortex, MD was increased in patients (p < 0.001), while surface-based analysis revealed focal cortical FA decreases. MD and FA changes were distributed inhomogeneously across the cortex, the MD increase being more widespread than the FA decrease. Cortical MD correlated with the Expanded Disability Status Scale (EDSS, r = 0.38, p = 0.03). Conclusion Damage of microstructural barriers occurs inhomogeneously across the cortex in RRMS and might be spatially more widespread than axonal degeneration. The results and, in particular, the correlation with the clinical status indicate that DTI might be a promising technique for the monitoring of cortical damage under treatment in larger clinical studies.
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Affiliation(s)
- Benjamin Stock
- Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany.,Department of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany.,Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Manoj Shrestha
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Alexander Seiler
- Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany.,Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Christian Foerch
- Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Elke Hattingen
- Department of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany
| | - Helmuth Steinmetz
- Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Ralf Deichmann
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Marlies Wagner
- Department of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany
| | - René-Maxime Gracien
- Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany.,Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
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Shrestha M, Nöth U, Deichmann R. Improved signal-to-noise ratio in EPI sequences with highly asymmetric spin echo and highly asymmetric STEAM preparations (HASE-EPI and HASTEAM-EPI). MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 32:549-558. [DOI: 10.1007/s10334-019-00749-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 12/20/2022]
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