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Drake CE, Cheng LK, Muszynski ND, Somarajan S, Paskaranandavadivel N, Angeli-Gordon TR, Du P, Bradshaw LA, Avci R. Electroanatomical mapping of the stomach with simultaneous biomagnetic measurements. Comput Biol Med 2023; 165:107384. [PMID: 37633085 DOI: 10.1016/j.compbiomed.2023.107384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 08/28/2023]
Abstract
Gastric motility is coordinated by bioelectric slow waves (SWs) and dysrhythmic SW activity has been linked with motility disorders. Magnetogastrography (MGG) is the non-invasive measurement of the biomagnetic fields generated by SWs. Dysrhythmia identification using MGG is currently challenging because source models are not well developed and the impact of anatomical variation is not well understood. A novel method for the quantitative spatial co-registration of serosal SW potentials, MGG, and geometric models of anatomical structures was developed and performed on two anesthetized pigs to verify feasibility. Electrode arrays were localized using electromagnetic transmitting coils. Coil localization error for the volume where the stomach is normally located under the sensor array was assessed in a benchtop experiment, and mean error was 4.2±2.3mm and 3.6±3.3° for a coil orientation parallel to the sensor array and 6.2±5.7mm and 4.5±7.0° for a perpendicular coil orientation. Stomach geometries were reconstructed by fitting a generic stomach to up to 19 localization coils, and SW activation maps were mapped onto the reconstructed geometries using the registered positions of 128 electrodes. Normal proximal-to-distal and ectopic SW propagation patterns were recorded from the serosa and compared against the simultaneous MGG measurements. Correlations between the center-of-gravity of normalized MGG and the mean position of SW activity on the serosa were 0.36 and 0.85 for the ectopic and normal propagation patterns along the proximal-distal stomach axis, respectively. This study presents the first feasible method for the spatial co-registration of MGG, serosal SW measurements, and subject-specific anatomy. This is a significant advancement because these data enable the development and validation of novel non-invasive gastric source characterization methods.
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Affiliation(s)
- Chad E Drake
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; Department of Surgery, Vanderbilt University, Nashville, TN, USA
| | | | | | | | | | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
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Drake CE, Cheng LK, Paskaranandavadivel N, Alighaleh S, Angeli-Gordon TR, Du P, Bradshaw LA, Avci R. Stomach Geometry Reconstruction Using Serosal Transmitting Coils and Magnetic Source Localization. IEEE Trans Biomed Eng 2023; 70:1036-1044. [PMID: 36121949 PMCID: PMC10069741 DOI: 10.1109/tbme.2022.3207770] [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] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Bioelectric slow waves (SWs) are a key regulator of gastrointestinal motility, and disordered SW activity has been linked to motility disorders. There is currently a lack of practical options for the acquisition of the 3D stomach geometry during research studies when medical imaging is challenging. Accurately recording the geometry of the stomach and co-registering electrode and sensor positions would provide context for in-vivo studies and aid the development of non-invasive methods of gastric SW assessment. METHODS A stomach geometry reconstruction method based on the localization of transmitting coils placed on the gastric serosa was developed. The positions and orientations of the coils, which represented boundary points and surface-normal vectors, were estimated using a magnetic source localization algorithm. Coil localization results were then used to generate surface models. The reconstruction method was evaluated against four 3D-printed anatomically realistic human stomach models and applied in a proof of concept in-vivo pig study. RESULTS Over ten repeated reconstructions, average Hausdorff distance and average surface-normal vector error values were 4.7 ±0.2 mm and 18.7 ±0.7° for the whole stomach, and 3.6 ±0.2 mm and 14.6 ±0.6° for the corpus. Furthermore, mean intra-array localization error was 1.4 ±1.1 mm for the benchtop experiment and 1.7 ±1.6 mm in-vivo. CONCLUSION AND SIGNIFICANCE Results demonstrated that the proposed reconstruction method is accurate and feasible. The stomach models generated by this method, when co-registered with electrode and sensor positions, could enable the investigation and validation of novel inverse analysis techniques.
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Stefan H, Rampp S. Interictal and Ictal MEG in presurgical evaluation for epilepsy surgery. ACTA EPILEPTOLOGICA 2020. [DOI: 10.1186/s42494-020-00020-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractAlthough presurgical evaluation of patients with pharamacoresistent focal epilepsies provides essential information for successful epilepsy surgery, there is still a need for further improvement. Developments of noninvasive electrophysiological recording and analysis techniques offer additional information based on interictal and ictal epileptic activities. In this review, we provide an overview on the application of ictal magnetoencephalography (MEG). The results of a literature research for published interictal/ictal MEG findings and experiences with own cases are demonstrated and discussed. Ictal MEG may provide added value in comparison to interictal recordings. The results may be more focal and closer to the invasively determined seizure onset zone. In some patients without clear interictal findings, ictal MEG could provide correct localization. Novel recording and analysis techniques facilitate ictal recordings. However, extended recording durations, movement and artifacts still represent practical limitations. Ictal MEG may provide added value regarding the localization of the seizure onset zone but depends on the selection of patients and the application of optimal analysis techniques.
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Souza VH, Matsuda RH, Peres ASC, Amorim PHJ, Moraes TF, Silva JVL, Baffa O. Development and characterization of the InVesalius Navigator software for navigated transcranial magnetic stimulation. J Neurosci Methods 2018; 309:109-120. [PMID: 30149047 DOI: 10.1016/j.jneumeth.2018.08.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 08/07/2018] [Accepted: 08/20/2018] [Indexed: 11/25/2022]
Abstract
BACKGROUND Neuronavigation provides visual guidance of an instrument during procedures of neurological interventions, and has been shown to be a valuable tool for accurately positioning transcranial magnetic stimulation (TMS) coils relative to an individual's anatomy. Despite the importance of neuronavigation, its high cost, low portability, and low availability of magnetic resonance imaging facilities limit its insertion in research and clinical environments. NEW METHOD We have developed and validated the InVesalius Navigator as the first free, open-source software for image-guided navigated TMS, compatible with multiple tracking devices. A point-based, co-registration algorithm and a guiding interface were designed for tracking any instrument (e.g. TMS coils) relative to an individual's anatomy. RESULTS Localization, precision errors, and repeatability were measured for two tracking devices during navigation in a phantom and in a simulated TMS study. Errors were measured in two commercial navigated TMS systems for comparison. Localization error was about 1.5 mm, and repeatability was about 1 mm for translation and 1° for rotation angles, both within limits established in the literature. COMPARISON WITH EXISTING METHODS Existing TMS neuronavigation software programs are not compatible with multiple tracking devices, and do not provide an easy to implement platform for custom tools. Moreover, commercial alternatives are expensive with limited portability. CONCLUSIONS InVesalius Navigator might contribute to improving spatial accuracy and the reliability of techniques for brain interventions by means of an intuitive graphical interface. Furthermore, the software can be easily integrated into existing neuroimaging tools, and customized for novel applications such as multi-locus and/or controllable-pulse TMS.
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Affiliation(s)
- Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
| | - Renan H Matsuda
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
| | - André S C Peres
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil; Instituto Internacional de Neurociência de Natal Edmond e Lily Safra, Instituto Santos Dumont, Rodovia RN 160 Km 03, 3003, 59280-000, Macaíba, RN, Brazil.
| | - Paulo Henrique J Amorim
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Thiago F Moraes
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Jorge Vicente L Silva
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
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Reliability for non-invasive somatosensory cortex localization: Implications for pre-surgical mapping. Clin Neurol Neurosurg 2015; 139:224-9. [DOI: 10.1016/j.clineuro.2015.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/21/2015] [Accepted: 10/05/2015] [Indexed: 11/24/2022]
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Foldes ST, Weber DJ, Collinger JL. MEG-based neurofeedback for hand rehabilitation. J Neuroeng Rehabil 2015; 12:85. [PMID: 26392353 PMCID: PMC4578759 DOI: 10.1186/s12984-015-0076-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Providing neurofeedback (NF) of motor-related brain activity in a biologically-relevant and intuitive way could maximize the utility of a brain-computer interface (BCI) for promoting therapeutic plasticity. We present a BCI capable of providing intuitive and direct control of a video-based grasp. METHODS Utilizing magnetoencephalography's (MEG) high temporal and spatial resolution, we recorded sensorimotor rhythms (SMR) that were modulated by grasp or rest intentions. SMR modulation controlled the grasp aperture of a stop motion video of a human hand. The displayed hand grasp position was driven incrementally towards a closed or opened state and subjects were required to hold the targeted position for a time that was adjusted to change the task difficulty. RESULTS We demonstrated that three individuals with complete hand paralysis due to spinal cord injury (SCI) were able to maintain brain-control of closing and opening a virtual hand with an average of 63 % success which was significantly above the average chance rate of 19 %. This level of performance was achieved without pre-training and less than 4 min of calibration. In addition, successful grasp targets were reached in 1.96 ± 0.15 s. Subjects performed 200 brain-controlled trials in approximately 30 min excluding breaks. Two of the three participants showed a significant improvement in SMR indicating that they had learned to change their brain activity within a single session of NF. CONCLUSIONS This study demonstrated the utility of a MEG-based BCI system to provide realistic, efficient, and focused NF to individuals with paralysis with the goal of using NF to induce neuroplasticity.
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Affiliation(s)
- Stephen T Foldes
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Douglas J Weber
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Bioengineering, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Jennifer L Collinger
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA.
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Department of Bioengineering, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
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Johnson MJ, Simpson MIG, Currow DC, Millman RE, Hart SP, Green G. Magnetoencephalography to investigate central perception of exercise-induced breathlessness in people with chronic lung disease: a feasibility pilot. BMJ Open 2015; 5:e007535. [PMID: 26063567 PMCID: PMC4574009 DOI: 10.1136/bmjopen-2014-007535] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Neuroimaging in chronic breathlessness is challenging. The study objective was to test the feasibility of magnetoencephalography (MEG) for functional neuroimaging of people with chronic breathlessness. DESIGN Feasibility pilot study. SETTING Respiratory clinic out-patients. PARTICIPANTS 8 patients (mean age=62; (range 47-83); 4 men) with chronic non-malignant lung disease; modified MRC breathlessness score ≥ (median mMRC=4), intensity of exercise-induced breathlessness >3/10; no contraindication to MRI scanning. METHODS AND MEASURES 4 MEG scans were conducted for each participant: (1) at rest (5 mins), (2) postseated leg exercise-induced breathlessness during recovery (10 mins). Recovery scans (2) were conducted with/without facial airflow in random order; both scans were repeated 1 h later. Participants rated breathlessness intensity (0-10 Numerical Rating Scale (NRS)) at baseline, maximal exertion and every minute during recovery, and rated acceptability of study procedures at the end of the study (0-10 NRS). A structural MRI scan was conducted for MEG coregistration and source-space analyses. Rest data were compared with data from healthy volunteers (N=6; 5 men; mean age=30.7 years ± 3.9 years). RESULTS Exercises and MEG scanning were acceptable to all participants; 7/8 completed the MRI scans. Maximum breathlessness intensity was induced by 5 min' exercise. The same level was induced for repeat scans (median=8; IQR=7-8). All recovered to baseline by 10 min. Time-frequency profiles of data from the first and last 3 min were analysed in MEG source space based on breathlessness location estimates. Source localisation was performed, but anatomical source inference was limited to the level of the lobe. Differences in areas of activity were seen: during recovery scans; with and without airflow; and between participants/normal volunteers at rest. CONCLUSIONS MEG is a feasible method to investigate exercise-induced breathlessness in people breathless with chronic lung disease, and able to identify neural activity related to changes in breathlessness.
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Affiliation(s)
| | | | - David C Currow
- Discipline, Palliative and Supportive Services, Flinders University, Adelaide, Australia
| | | | - Simon P Hart
- Hull York Medical School, University of Hull, Hull, UK
| | - Gary Green
- Hull York Medical School, University of Hull, Hull, UK
- York Neuroimaging Centre, University of York, York, UK
- Department of Psychology, University of York, York, UK
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