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Duraffourg M, Rougereau G, Fawaz R, Ltaief A, Jacquesson T, Freydier M, Baude C, Robert R, Mertens P. Lumbosacral plexus and pudendal nerve magnetic resonance tractography: A systematic review of the clinical applications for pudendal neuralgia. Magn Reson Imaging 2024:S0730-725X(24)00161-9. [PMID: 38797289 DOI: 10.1016/j.mri.2024.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/18/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Diffusion tensor imaging (DTI) is commonly used to establish three-dimensional mapping of white-matter bundles in the supraspinal central nervous system. DTI has also been the subject of many studies on cranial and peripheral nerves. This non-invasive imaging technique enables virtual dissection of nerves in vivo and provides specific measurements of microstructural integrity. Adverse effects on the lumbosacral plexus may be traumatic, compressive, tumoral, or malformative and thus require dedicated treatment. DTI could lead to new perspectives in pudendal neuralgia diagnosis and management. We performed a systematic review of all articles or posters reporting results and protocols for lumbosacral plexus mapping using the DTI technique between January 2011 and December 2023. Twenty-nine articles published were included. Ten studies with a total of 351 participants were able to track the lumbosacral plexus in a physiological context and 19 studies with a total of 402 subjects tracked lumbosacral plexus in a pathological context. Tractography was performed on a 1.5T or 3T MRI system. DTI applied to the lumbosacral plexus and pudendal nerve is feasible but no microstructural normative value has been proposed for the pudendal nerve. The most frequently tracking parameters used in our review are: 3T MRI, b-value of 800 s/mm2, 33 directions, 3 × 3 × 3 mm3, AF threshold of 0.1, minimum fiber length of 10 mm, bending angle of 30°, and 3DT2 TSE anatomical resolution. Increased use of DTI could lead to new perspectives in the management of pudendal neuralgia due to entrapment syndrome, whether at the diagnostic, prognostic, or preoperative planning level. Prospective studies of healthy subjects and patients with the optimal acquisition parameters described above are needed to establish the accuracy of MR tractography for diagnosing pudendal neuralgia and other intrapelvic nerve entrapments.
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Affiliation(s)
- M Duraffourg
- Unité de Neuromodulation Polyvalente, Service de Neurochirurgie fonctionnelle de la moelle et des nerfs périphériques - Hospices Civils de Lyon, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Centre d'Évaluation et de Traitement de la Douleur, Hospices Civils de Lyon- Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France
| | - G Rougereau
- Service de chirurgie orthopédique et traumatologique Hôpital Pitié Salpetrière, Paris, France
| | - R Fawaz
- Unité de Neuromodulation Polyvalente, Service de Neurochirurgie fonctionnelle de la moelle et des nerfs périphériques - Hospices Civils de Lyon, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Centre d'Évaluation et de Traitement de la Douleur, Hospices Civils de Lyon- Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Service de Neurochirurgie - Hôpital d'Instruction des Armées Percy, Clamart, France.
| | - A Ltaief
- Service d'imagerie médicale et interventionnelle - Hospices Civils de Lyon, Hôpital Edouard Herriot, Lyon, France
| | - T Jacquesson
- Service de Neurochirurgie crânienne générale, tumorale et vasculaire - Hospices Civils de Lyon- Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Faculté de Médecine Lyon Est, Université Claude Bernard, Lyon, France
| | - M Freydier
- Centre d'Évaluation et de Traitement de la Douleur - Centre Hospitalier de Macon, Macon, France; Centre d'Évaluation et de Traitement de la Douleur - Médipôle Hôpital Mutualiste, Villeurbanne, France
| | - C Baude
- Centre d'Évaluation et de Traitement de la Douleur - Médipôle Hôpital Mutualiste, Villeurbanne, France
| | - R Robert
- Service de chirurgie - Hôpital Privé du Confluent, Nantes, France; Faculté de Médecine de Nantes, Nantes, France
| | - P Mertens
- Unité de Neuromodulation Polyvalente, Service de Neurochirurgie fonctionnelle de la moelle et des nerfs périphériques - Hospices Civils de Lyon, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Centre d'Évaluation et de Traitement de la Douleur, Hospices Civils de Lyon- Hôpital neurologique et neurochirurgical Pierre Wertheimer, Bron, France; Faculté de Médecine Lyon Est, Université Claude Bernard, Lyon, France
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Kanazawa Y, Ikemitsu N, Kinjo Y, Harada M, Hayashi H, Taniguchi Y, Ito K, Bito Y, Matsumoto Y, Haga A. Differences of white matter structure for diffusion kurtosis imaging using voxel-based morphometry and connectivity analysis. BJR Open 2024; 6:tzad003. [PMID: 38352183 PMCID: PMC10860519 DOI: 10.1093/bjro/tzad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/13/2023] [Accepted: 10/17/2023] [Indexed: 02/16/2024] Open
Abstract
Objectives In a clinical study, diffusion kurtosis imaging (DKI) has been used to visualize and distinguish white matter (WM) structures' details. The purpose of our study is to evaluate and compare the diffusion tensor imaging (DTI) and DKI parameter values to obtain WM structure differences of healthy subjects. Methods Thirteen healthy volunteers (mean age, 25.2 years) were examined in this study. On a 3-T MRI system, diffusion dataset for DKI was acquired using an echo-planner imaging sequence, and T1-weghted (T1w) images were acquired. Imaging analysis was performed using Functional MRI of the brain Software Library (FSL). First, registration analysis was performed using the T1w of each subject to MNI152. Second, DTI (eg, fractional anisotropy [FA] and each diffusivity) and DKI (eg, mean kurtosis [MK], radial kurtosis [RK], and axial kurtosis [AK]) datasets were applied to above computed spline coefficients and affine matrices. Each DTI and DKI parameter value for WM areas was compared. Finally, tract-based spatial statistics (TBSS) analysis was performed using each parameter. Results The relationship between FA and kurtosis parameters (MK, RK, and AK) for WM areas had a strong positive correlation (FA-MK, R2 = 0.93; FA-RK, R2 = 0.89) and a strong negative correlation (FA-AK, R2 = 0.92). When comparing a TBSS connection, we found that this could be observed more clearly in MK than in RK and FA. Conclusions WM analysis with DKI enable us to obtain more detailed information for connectivity between nerve structures. Advances in knowledge Quantitative indices of neurological diseases were determined using segmenting WM regions using voxel-based morphometry processing of DKI images.
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Affiliation(s)
- Yuki Kanazawa
- Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Natsuki Ikemitsu
- Division of Radiological Technology, Okayama University Hospital, Okayama 700-8558, Japan
| | - Yuki Kinjo
- Department of Radiology, Higashihiroshima Medical Center, National Hospital Organization, Hiroshima 739-0041, Japan
| | - Masafumi Harada
- Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Hiroaki Hayashi
- College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa 920-0942, Japan
| | - Yo Taniguchi
- FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan
| | - Kosuke Ito
- FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan
| | | | - Yuki Matsumoto
- Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Akihiro Haga
- Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan
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Szaro P, Suresh R, Molokwu B, Sibala DR, Mendiratta D, Chu A, McGrath A. Magnetic resonance imaging for diagnosis of suspected neurogenic thoracic outlet syndrome-a systematic scoping review. Front Physiol 2023; 14:1198165. [PMID: 37920804 PMCID: PMC10619157 DOI: 10.3389/fphys.2023.1198165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 10/06/2023] [Indexed: 11/04/2023] Open
Abstract
Background: Neurogenic Thoracic Outlet Syndrome (nTOS) is a rare pathology caused by dynamic conditions or compression of neurovascular structures in the thoracic outlet region. nTOS can be difficult to diagnose due to nonspecific symptoms and magnetic resonance imaging (MRI) techniques are increasingly used to aid the diagnosis and surgical planning. This scoping systematic review explores how MRI is used for diagnosing nTOS and summarizes details of published MRI protocols. Methods: A systematic screening of PubMed, Cochrane, Web of Science, and CINAHL databases using PRISMA-IPD guidelines was conducted in September 2022 to include full-text English papers on MRI and nTOS. Inclusion criteria involved studies describing MRI protocols for the diagnosis of TOS, with a focus on the imaging sequences and protocols. Results: 6289 papers were screened to include 28 papers containing details of MRI protocols. The details of MRI protocols in the analyzed articles were incomplete in all studies. Most authors used 1.5T systems and included T1 and T2-weighted sequences. Most studies applied fat suppression, mainly with STIR. Positioning of the arm differed between studies, including neutral, hyperabducted and abducted and externally rotated positions. Conclusion: Our review highlights a prevalent lack of detailed MRI protocol documentation for brachial plexus. Authors primarily rely on conventional 1.5T systems, employing standard T1 and T2-weighted sequences. The adoption of novel MRI sequences is notably lacking, and fat suppression techniques predominantly adhere to older methods as STIR. There is a clear imperative for authors to provide more comprehensive reporting of the MRI protocols utilized in their studies, ultimately enhancing comparability and clinical applicability. Establishing clear protocol reporting guidelines is crucial to allow for comparison between studies.
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Affiliation(s)
- Pawel Szaro
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Musculoskeletal Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Rohan Suresh
- Department of Orthopaedics, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Brian Molokwu
- Department of Orthopaedics, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Dhiraj Raju Sibala
- Department of Orthopaedics, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Dhruv Mendiratta
- Department of Orthopaedics, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Alice Chu
- Department of Orthopaedics, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Aleksandra McGrath
- Department of Clinical Sciences, Umeå University, Umeå, Sweden
- Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden
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Szaro P, McGrath A, Ciszek B, Geijer M. Magnetic resonance imaging of the brachial plexus. Part 1: Anatomical considerations, magnetic resonance techniques, and non-traumatic lesions. Eur J Radiol Open 2022; 9:100392. [PMID: 34988263 PMCID: PMC8695258 DOI: 10.1016/j.ejro.2021.100392] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/30/2021] [Accepted: 12/12/2021] [Indexed: 12/28/2022] Open
Abstract
For magnetic resonance imaging (MRI) of non-traumatic brachial plexus (BP) lesions, sequences with contrast injection should be considered in the differentiation between tumors, infection, postoperative conditions, and post-radiation changes. The most common non-traumatic inflammatory BP neuropathy is radiation neuropathy. T2-weighted images may help to distinguish neoplastic infiltration showing a high signal from radiation-induced neuropathy with fibrosis presenting a low signal. MRI findings in inflammatory BP neuropathy are usually absent or discrete. Diffuse edema of the BP localized mainly in the supraclavicular part of BP, with side-to-side differences, and shoulder muscle denervation may be found on MRI. BP infection is caused by direct infiltration from septic arthritis of the shoulder joint, spondylodiscitis, or lung empyema. MRI may help to narrow down the list of differential diagnoses of tumors. The most common tumor of BP is metastasis. The most common primary tumor of BP is neurofibroma, which is visible as fusiform thickening of a nerve. In its solitary state, it may be challenging to differentiate from a schwannoma. The most common MRI finding is a neurogenic variant of thoracic outlet syndrome with an asymmetry of signal and thickness of the BP with edema. In abduction, a loss of fat directly related to the BP may be seen. Diffusion tensor imaging is a promising novel MRI sequences; however, the small diameter of the nerves contributing to the BP and susceptibility to artifacts may be challenging in obtaining sufficiently high-quality images. MRI allows narrowing the list of differential diagnoses of brachial plexus lesions. MRI helps to distinguish neoplastic infiltration from radiation neuropathy in T2-weighted images. Differentiation between tumors, infection, postoperative conditions and post-radiation changes is possible with contrast. MRI helps to determine the extent of the infection. Diffusion tensor MRI is a promising method for brachial plexus assessment.
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Affiliation(s)
- Pawel Szaro
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Musculoskeletal Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Alexandra McGrath
- Umeå University, Faculty of Medicine, Department of Clinical Sciences, Professional Development. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sweden
| | - Bogdan Ciszek
- Department of Descriptive and Clinical Anatomy, Centre of Biostructure Research, Medical University of Warsaw, Chałubinskiego 5, 02-004 Warsaw, Poland.,Department of Neurosurgery, Bogdanowicz Memorial Hospital, Niekłanska 4/24, 03-924 Warsaw, Poland
| | - Mats Geijer
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Musculoskeletal Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Clinical Sciences, Lund University, Lund, Sweden
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van Rosmalen MHJ, Goedee HS, Derks R, Asselman F, Verhamme C, de Luca A, Hendrikse J, van der Pol WL, Froeling M. Quantitative magnetic resonance imaging of the brachial plexus shows specific changes in nerve architecture in chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy and motor neuron disease. Eur J Neurol 2021; 28:2716-2726. [PMID: 33934438 PMCID: PMC8362016 DOI: 10.1111/ene.14896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/12/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND The immunological pathophysiologies of chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) differ considerably, but neither has been elucidated completely. Quantitative magnetic resonance imaging (MRI) techniques such as diffusion tensor imaging, T2 mapping, and fat fraction analysis may indicate in vivo pathophysiological changes in nerve architecture. Our study aimed to systematically study nerve architecture of the brachial plexus in patients with CIDP, MMN, motor neuron disease (MND) and healthy controls using these quantitative MRI techniques. METHODS We enrolled patients with CIDP (n = 47), MMN (n = 29), MND (n = 40) and healthy controls (n = 10). All patients underwent MRI of the brachial plexus and we obtained diffusion parameters, T2 relaxation times and fat fraction using an automated processing pipeline. We compared these parameters between groups using a univariate general linear model. RESULTS Fractional anisotropy was lower in patients with CIDP compared to healthy controls (p < 0.001), patients with MND (p = 0.010) and MMN (p < 0.001). Radial diffusivity was higher in patients with CIDP compared to healthy controls (p = 0.015) and patients with MND (p = 0.001) and MMN (p < 0.001). T2 relaxation time was elevated in patients with CIDP compared to patients with MND (p = 0.023). Fat fraction was lower in patients with CIDP and MMN compared to patients with MND (both p < 0.001). CONCLUSION Our results show that quantitative MRI parameters differ between CIDP, MMN and MND, which may reflect differences in underlying pathophysiological mechanisms.
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Affiliation(s)
- Marieke H. J. van Rosmalen
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - H. Stephan Goedee
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Rosina Derks
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Fay‐Lynn Asselman
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Camiel Verhamme
- Department of NeurologyAmsterdam NeuroscienceAmsterdam University Medical CentersUniversity of AmsterdamAmsterdamThe Netherlands
| | - Alberto de Luca
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - J. Hendrikse
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Martijn Froeling
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
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Gilcrease-Garcia BM, Deshmukh SD, Parsons MS. Anatomy, Imaging, and Pathologic Conditions of the Brachial Plexus. Radiographics 2021; 40:1686-1714. [PMID: 33001787 DOI: 10.1148/rg.2020200012] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The brachial plexus is an intricate anatomic structure with an important function: providing innervation to the upper extremity, shoulder, and upper chest. Owing to its complex form and longitudinal course, the brachial plexus can be challenging to conceptualize in three dimensions, which complicates evaluations in standard orthogonal imaging planes. The components of the brachial plexus can be determined by using key anatomic landmarks. Applying this anatomic knowledge, a radiologist should then be able to identify pathologic appearances of the brachial plexus by using imaging modalities such as MRI, CT, and US. Brachial plexopathies can be divided into two broad categories that are based on disease origin: traumatic and nontraumatic. In the traumatic plexopathy group, there are distinct imaging findings and management methods for pre- versus postganglionic injuries. For nontraumatic plexopathies, having access to an accurate patient history is often crucial. Knowledge of the timing of radiation therapy is critical to diagnosing post-radiation therapy brachial plexopathy. In acute brachial neuritis, antecedent stressors occur within a specific time frame. Primary and secondary tumors of the brachial plexus are not uncommon, with the most common primary tumors being peripheral nerve sheath tumors. Direct extension and metastasis from primary malignancies such as breast and lung cancer can occur. Although diagnosing a brachial plexus anomaly is potentially perplexing, it can be straightforward if it is based on foundational knowledge of anatomy, imaging findings, and pathologic features. ©RSNA, 2020.
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Affiliation(s)
- Brian M Gilcrease-Garcia
- From the Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Ill (B.M.G., S.D.D.); and Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Box 8131, St Louis, MO 63110 (M.S.P.)
| | - Swati D Deshmukh
- From the Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Ill (B.M.G., S.D.D.); and Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Box 8131, St Louis, MO 63110 (M.S.P.)
| | - Matthew S Parsons
- From the Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Ill (B.M.G., S.D.D.); and Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Box 8131, St Louis, MO 63110 (M.S.P.)
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Wade RG, Teh I, Andersson G, Yeh FC, Wiberg M, Bourke G. Fractional anisotropy thresholding for deterministic tractography of the roots of the brachial plexus. Sci Rep 2021; 11:80. [PMID: 33420207 PMCID: PMC7794285 DOI: 10.1038/s41598-020-79840-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 12/07/2020] [Indexed: 02/03/2023] Open
Abstract
Diffusion tensor imaging (DTI) metrics, such as the fractional anisotropy (FA) and estimates of diffusivity are sensitive to the microstructure of peripheral nerves and may be displayed as tractograms. However, the ideal conditions for tractography of the roots of the brachial plexus are unclear, which represents the rationale for this study. Ten healthy adults were scanned using a Siemens Prisma (3T) and single-shot echo-planar imaging (b-value 0/1000 s/mm2, 64 directions, 2.5 mm3 with 4 averages; repeated in opposing phase encoding directions). Susceptibility correction and tractography were performed in DSI Studio by two independent raters. The effect of FA thresholding at increments of 0.01 (from 0.04 to 0.10) were tested. The mean FA varied between subjects by 2% (95% CI 1%, 3%). FA thresholds of 0.04, 0.05 and 0.06 all propagated 96% of tracts representing the roots; thresholding at 0.07 yielded 4% fewer tracts (p = 0.2), 0.08 yielded 11% fewer tracts (p = 0.008), 0.09 yielded 15% fewer tracts (p = 0.001) and 0.1 yielded 20% fewer tracts (p < 0.001). There was < 0.1% inter-rater variability in the measured FA and 99% agreement for tractography (κ = 0.92, p < 0.001). The fractional anisotropy thresholds required to generate tractograms of the roots of the brachial plexus appears to be lower than those used in the brain. We provide estimates of the probability of generating true tracts for each spinal nerve root of the brachial plexus, at different fractional anisotropy thresholds.
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Affiliation(s)
- Ryckie G Wade
- Academic Plastic Surgery Office, Department of Plastic and Reconstructive Surgery, Leeds General Infirmary, Leeds Teaching Hospitals Trust, Leeds, LS1 3EX, UK. .,Faculty of Medicine and Health Sciences, University of Leeds, Leeds, UK.
| | - Irvin Teh
- Leeds Institute for Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Gustav Andersson
- Department of Integrative Medical Biology, Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Faculty of Medicine, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, USA
| | - Mikael Wiberg
- Department of Integrative Medical Biology, Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Faculty of Medicine, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Grainne Bourke
- Academic Plastic Surgery Office, Department of Plastic and Reconstructive Surgery, Leeds General Infirmary, Leeds Teaching Hospitals Trust, Leeds, LS1 3EX, UK.,Faculty of Medicine and Health Sciences, University of Leeds, Leeds, UK.,Department of Integrative Medical Biology, Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Faculty of Medicine, Umeå University, Umeå, Sweden
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Perumal AR, Anyamele UA, Bhogal RK, McCauley G, Teh I, Bourke G, Rankine JJ, Wade RG. Incidental findings associated with magnetic resonance imaging of the brachial plexus. Br J Radiol 2021; 94:20200921. [PMID: 33156721 PMCID: PMC7774680 DOI: 10.1259/bjr.20200921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/20/2020] [Accepted: 11/03/2020] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The identification and management of incidental findings is becoming increasingly problematic, particularly in relation to brachial plexus imaging because the prevalence is unknown. Therefore, we aimed to estimate the prevalence of incidental findings in symptomatic patients undergoing MRI of the brachial plexus. METHODS This retrospective cohort study included all children and adults who underwent MRI over a 12-year period, in a tertiary care centre in the UK. An incidental finding was any abnormality which was not a direct injury to or disease-process of the brachial plexus. An "incidentaloma" was defined by the need for further investigation or treatment. Multivariable logistic regression was used to estimate the odds ratio (OR) of an "incidentaloma". To estimate which factors were associated with the incident rate ratio (IRR) of incidental findings, multivariable Poisson regression was used. RESULTS Overall, 502 scans (72%) reported incidental anomalies. Although the number of MRIs performed per annum increased by 23%, the prevalence of "incidentalomas" remained static (p = 0.766). Musculoskeletal incidental findings were the most prevalent (63%) and when identified, there were a median of 3 incidental anomalies per patient. Overall, 125 (18%) anomalies were "incidentalomas" which required further investigation or treatment. The odds of having further investigation or treatment was strongly related to the frequency of incidental findings [adjusted OR 1.16 (95% CI 1.08, 1.24)] and when a tumour was identified [adjusted OR 2.86 (95% CI 1.81, 4.53)]. The number of incidental findings recorded per scan increased when trainees co-reported with consultants [adjusted IRR 0.36 (95% CI 0.05, 0.67)] and in the presence of a tumour [adjusted IRR 0.39 (95% CI 0.28, 0.49)]. CONCLUSIONS The prevalence of clinically important incidental findings on brachial plexus MRI is lower than organ-specific imaging, but still 18% of scans identified an 'incidentaloma' which required further investigation or treatment. ADVANCES IN KNOWLEDGE This cohort study shows that approximately 1 in 5 symptomatic patients undergoing a brachial plexus MRI had a clinically important incidental findings, which required further investigation or treatment. This information can be used to inform patients consenting to clinical or research imaging.
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Affiliation(s)
- Antonia R Perumal
- Faculty of Medicine and Health Sciences, University of Leeds, Leeds, UK
| | | | - Rayna K Bhogal
- Faculty of Medicine and Health Sciences, University of Leeds, Leeds, UK
| | | | - Irvin Teh
- Leeds Institute for Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | | | - James J Rankine
- Department of Radiology, Leeds Teaching Hospitals Trust, Leeds, UK
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Diffusion tensor imaging of the roots of the brachial plexus: a systematic review and meta-analysis of normative values. Clin Transl Imaging 2020; 8:419-431. [PMID: 33282795 PMCID: PMC7708343 DOI: 10.1007/s40336-020-00393-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023]
Abstract
Purpose Diffusion tensor magnetic resonance imaging (DTI) characterises tissue microstructure and provides proxy measures of myelination, axon diameter, fibre density and organisation. This may be valuable in the assessment of the roots of the brachial plexus in health and disease. Therefore, there is a need to define the normal DTI values. Methods The literature was systematically searched for studies of asymptomatic adults who underwent DTI of the brachial plexus. Participant characteristics, scanning protocols, and measurements of the fractional anisotropy (FA) and mean diffusivity (MD) of each spinal root were extracted by two independent review authors. Generalised linear modelling was used to estimate the effect of experimental conditions on the FA and MD. Meta-analysis of root-level estimates was performed using Cohen's method with random effects. Results Nine articles, describing 316 adults (1:1 male:female) of mean age 35 years (SD 6) were included. Increments of ten diffusion sensitising gradient directions reduced the mean FA by 0.01 (95% CI 0.01, 0.03). Each year of life reduced the mean MD by 0.03 × 10-3 mm2/s (95% CI 0.01, 0.04). At 3-T, the pooled mean FA of the roots was 0.36 (95% CI 0.34, 0.38; I 2 98%). The pooled mean MD of the roots was 1.51 × 10-3 mm2/s (95% CI 1.45, 1.56; I 2 99%). Conclusions The FA and MD of the roots of the brachial plexus vary according to experimental conditions and participant factors. We provide summary estimates of the normative values in different conditions which may be valuable to researchers and clinicians alike.
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Wade RG, Bligh ER, Nar K, Stone RS, Roberts DJ, Teh I, Bourke G. The Geometry of the roots of the Brachial Plexus. J Anat 2020; 237:999-1005. [PMID: 32628794 PMCID: PMC7704236 DOI: 10.1111/joa.13270] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 12/28/2022] Open
Abstract
Diffusion tensor magnetic resonance imaging (DTI) can be used to reconstruct the brachial plexus in 3D via tracts connecting contiguous diffusion tensors with similar primary eigenvector orientations. When creating DTI tractograms, the turning angle of connecting lines (step angle) must be prescribed by the user; however, the literature is lacking detailed geometry of brachial plexus to inform such decisions. Therefore, the spinal cord and brachial plexus of 10 embalmed adult cadavers were exposed bilaterally by posterior dissection. Photographs were taken under standardised conditions and spatially calibrated in MATLAB. The roots of the brachial plexus were traced from the dorsal root entry zone for 5 cm laterally using a 2.5‐mm2 Cartesian grid overlay. The trace was composed of points connected by lines, and the turning angle between line segments (the step angle) was resolved. Our data show that the geometry of the roots increased in tortuosity from C5 to T1, with no significant differences between sides. The 1st thoracic root had the most tortuous course, turning through a maximum angle of 56° per 2.5 mm (99% CI 44° to 70°). Significantly higher step angles and greater variability were observed in the medial 2 cm of the roots of the brachial plexus, where the dorsal and ventral rootlets coalesce to form the spinal root. Throughout the brachial plexus, the majority of step angles (>50%) were smaller than 20° and <1% of step angles exceeded 70°. The geometry of the brachial plexus increases in tortuosity from C5 to T1. To reconstruct 99% of tracts representing the roots of the brachial plexus by DTI tractography, users can either customise the step angle per root based on our findings or select a universal threshold of 70°.
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Affiliation(s)
- Ryckie G Wade
- Leeds Institute for Medical Research, University of Leeds, Leeds, UK.,Department of Plastic and Reconstructive Surgery, Leeds Teaching Hospitals Trust, Leeds
| | - Emily R Bligh
- Division of Anatomy, Leeds Institute of Medical Education, University of Leeds, Leeds, UK.,Faculty of Medicine, Dentistry & Health, University of Sheffield Medical School, Sheffield, UK
| | - Kieran Nar
- Faculty of Engineering, University of Sheffield, Sheffield, UK
| | | | - David J Roberts
- Division of Anatomy, Leeds Institute of Medical Education, University of Leeds, Leeds, UK
| | - Irvin Teh
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Grainne Bourke
- Leeds Institute for Medical Research, University of Leeds, Leeds, UK.,Department of Plastic and Reconstructive Surgery, Leeds Teaching Hospitals Trust, Leeds
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11
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Wade RG, Tanner SF, Teh I, Ridgway JP, Shelley D, Chaka B, Rankine JJ, Andersson G, Wiberg M, Bourke G. Diffusion Tensor Imaging for Diagnosing Root Avulsions in Traumatic Adult Brachial Plexus Injuries: A Proof-of-Concept Study. Front Surg 2020; 7:19. [PMID: 32373625 PMCID: PMC7177010 DOI: 10.3389/fsurg.2020.00019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/23/2020] [Indexed: 01/09/2023] Open
Abstract
Cross-sectional MRI has modest diagnostic accuracy for diagnosing traumatic brachial plexus root avulsions. Consequently, patients either undergo major exploratory surgery or months of surveillance to determine if and what nerve reconstruction is needed. This study aimed to develop a diffusion tensor imaging (DTI) protocol at 3 Tesla to visualize normal roots and identify traumatic root avulsions of the brachial plexus. Seven healthy adults and 12 adults with known (operatively explored) unilateral traumatic brachial plexus root avulsions were scanned. DTI was acquired using a single-shot echo-planar imaging sequence at 3 Tesla. The brachial plexus was visualized by deterministic tractography. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for injured and avulsed roots in the lateral recesses of the vertebral foramen. Compared to healthy nerves roots, the FA of avulsed nerve roots was lower (mean difference 0.1 [95% CI 0.07, 0.13]; p < 0.001) and the MD was greater (mean difference 0.32 × 10-3 mm2/s [95% CI 0.11, 0.53]; p < 0.001). Deterministic tractography reconstructed both normal roots and root avulsions of the brachial plexus; the negative-predictive value for at least one root avulsion was 100% (95% CI 78, 100). Therefore, DTI might help visualize both normal and injured roots of the brachial plexus aided by tractography. The precision of this technique and how it relates to neural microstructure will be further investigated in a prospective diagnostic accuracy study of patients with acute brachial plexus injuries.
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Affiliation(s)
- Ryckie G Wade
- Department of Plastic and Reconstructive Surgery, Leeds Teaching Hospitals Trust, Leeds, United Kingdom.,Faculty of Medicine and Health Sciences, University of Leeds, Leeds, United Kingdom
| | - Steven F Tanner
- National Institute for Health Research (NIHR), Leeds Biomedical Research Centre, Leeds, United Kingdom.,Department of Medical Physics and Engineering, Leeds Teaching Hospitals Trust, Leeds, United Kingdom
| | - Irvin Teh
- Leeds Institute for Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - John P Ridgway
- National Institute for Health Research (NIHR), Leeds Biomedical Research Centre, Leeds, United Kingdom.,Department of Medical Physics and Engineering, Leeds Teaching Hospitals Trust, Leeds, United Kingdom
| | - David Shelley
- The Advanced Imaging Centre, Leeds Teaching Hospitals Trust, Leeds, United Kingdom
| | - Brian Chaka
- National Institute for Health Research (NIHR), Leeds Biomedical Research Centre, Leeds, United Kingdom
| | - James J Rankine
- Department of Radiology, Leeds Teaching Hospitals Trust, Leeds, United Kingdom
| | - Gustav Andersson
- Department of Integrative Medical Biology (Anatomy), Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science (Hand and Plastic Surgery), Faculty of Medicine, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Mikael Wiberg
- Department of Integrative Medical Biology (Anatomy), Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science (Hand and Plastic Surgery), Faculty of Medicine, Umeå University, Umeå, Sweden
| | - Grainne Bourke
- Department of Plastic and Reconstructive Surgery, Leeds Teaching Hospitals Trust, Leeds, United Kingdom.,Faculty of Medicine and Health Sciences, University of Leeds, Leeds, United Kingdom.,Department of Integrative Medical Biology (Anatomy), Faculty of Medicine, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science (Hand and Plastic Surgery), Faculty of Medicine, Umeå University, Umeå, Sweden
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12
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Shim E, Lee E, Lee JW, Kang Y, Ahn JM, Kang HS. Feasibility of postoperative 3-tesla diffusion tensor imaging in cervical spondylotic myelopathy: A comparison of single-shot EPI and multi-shot EPI. Eur J Radiol 2020; 122:108751. [DOI: 10.1016/j.ejrad.2019.108751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/22/2019] [Accepted: 11/13/2019] [Indexed: 10/25/2022]
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13
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Oudeman J, Eftimov F, Strijkers GJ, Schneiders JJ, Roosendaal SD, Engbersen MP, Froeling M, Goedee HS, van Doorn PA, Caan MWA, van Schaik IN, Maas M, Nederveen AJ, de Visser M, Verhamme C. Diagnostic accuracy of MRI and ultrasound in chronic immune-mediated neuropathies. Neurology 2019; 94:e62-e74. [PMID: 31827006 DOI: 10.1212/wnl.0000000000008697] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 06/27/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To assess and compare the diagnostic performance of qualitative and (semi-)quantitative MRI and ultrasound for distinguishing chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) from segmental spinal muscular atrophy (sSMA). METHODS Patients with CIDP (n = 13), MMN (n = 10), or sSMA (n = 12) and healthy volunteers (n = 30) were included. MRI of the brachial plexus, using short tau inversion recovery (STIR), nerve-specific T2-weighted (magnetic resonance neurography [MRN]), and diffusion tensor imaging (DTI) sequences, was evaluated. Furthermore, with ultrasound, cross-sectional areas of the nerves were evaluated. Three radiologists blinded for diagnosis qualitatively scored hypertrophy and increased signal intensity (STIR and MRN), and intraobserver and interobserver agreement was assessed. For the (semi-)quantitative modalities, group differences and receiver operator characteristics were calculated. RESULTS Hypertrophy and increased signal intensity were found in all groups including healthy controls. Intraobserver and interobserver agreements varied considerably (intraclass correlation coefficients 0.00-0.811 and 0.101-0.491, respectively). DTI showed significant differences (p < 0.05) among CIDP, MMN, sSMA, and controls for fractional anisotropy, axial diffusivity, and radial diffusivity in the brachial plexus. Ultrasound showed significant differences in cross-sectional area (p < 0.05) among CIDP, MMN, and sSMA in upper arm and brachial plexus. For distinguishing immune-mediated neuropathies (CIDP and MMN) from sSMA, ultrasound yielded the highest area under the curve (0.870). CONCLUSION Qualitative assessment of hypertrophy and signal hyperintensity on STIR or MRN is of limited value. DTI measures may discriminate among CIDP, MMN, and sSMA. Currently, ultrasound may be the most appropriate diagnostic imaging aid in the clinical setting.
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Affiliation(s)
- Jos Oudeman
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands.
| | - Filip Eftimov
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Gustav J Strijkers
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Joppe J Schneiders
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Stefan D Roosendaal
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Maurits P Engbersen
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Martijn Froeling
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - H Stephan Goedee
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Pieter A van Doorn
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Matthan W A Caan
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Ivo N van Schaik
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Mario Maas
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Aart J Nederveen
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Marianne de Visser
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
| | - Camiel Verhamme
- From the Departments of Radiology and Nuclear Medicine (J.O., S.D.R., M.P.E., M.W.A.C., M.M., A.J.N.), Neurology (F.E., I.N.v.S., M.d.V., C.V.), and Biomedical Engineering and Physics (G.J.S., M.W.A.C.), Amsterdam UMC, University of Amsterdam; Departments of Radiology (J.J.S.) and Neurology (P.A.v.D.), Erasmus Medical Center, Rotterdam; and Departments of Radiology (M.F.) and Neurology (H.S.G.), University Medical Center Utrecht, the Netherlands
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Pereira Botelho D, Curran K, Lowery MM. Anatomically accurate model of EMG during index finger flexion and abduction derived from diffusion tensor imaging. PLoS Comput Biol 2019; 15:e1007267. [PMID: 31465437 PMCID: PMC6738720 DOI: 10.1371/journal.pcbi.1007267] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 09/11/2019] [Accepted: 07/08/2019] [Indexed: 01/31/2023] Open
Abstract
This study presents a modelling framework in which information on muscle fiber direction and orientation during contraction is derived from diffusion tensor imaging (DTI) and incorporated in a computational model of the surface electromyographic (EMG) signal. The proposed model makes use of the principle of reciprocity to simultaneously calculate the electric potentials produced at the recording electrode by charges distributed along an arbitrary number of muscle fibers within the muscle, allowing for a computationally efficient evaluation of extracellular motor unit action potentials. The approach is applied to the complex architecture of the first dorsal interosseous (FDI) muscle of the hand to simulate EMG during index finger flexion and abduction. Using diffusion tensor imaging methods, the results show how muscle fiber orientation and curvature in this intrinsic hand muscle change during flexion and abduction. Incorporation of anatomically accurate muscle architecture and other hand tissue morphologies enables the model to capture variations in extracellular action potential waveform shape across the motor unit population and to predict experimentally observed differences in EMG signal features when switching from index finger abduction to flexion. The simulation results illustrate how structural and electrical properties of the tissues comprising the volume conductor, in combination with fiber direction and curvature, shape the detected action potentials. Using the model, the relative contribution of motor units of different sizes located throughout the muscle under both conditions is examined, yielding a prediction of the detection profile of the surface EMG electrode array over the muscle cross-section. Advances in diffusion tensor imaging are providing new information on muscle architecture and the orientation of muscle fibers in vivo. The arrangement of muscle fibers, in combination with geometrical and electrical properties of the surrounding biological tissues, shapes the electrical signal recorded at the skin surface during muscle contraction. As new recording and analysis methods enable muscle and motor unit activity to be examined during complex dynamic contractions, changes in muscle fiber orientation and surrounding tissue properties pose challenges for the interpretation of these data. Here we incorporate details of tissue geometry and muscle fiber architecture obtained using anatomical and diffusion MRI into an anatomically accurate model of electromyography (EMG) signal generation in the first dorsal interosseous muscle of the hand. The new modeling approach presented integrates interdependent electrical and geometrical properties in an anatomically accurate manner, leading to a realistic EMG model where tissue electrical properties are inherently related to bioelectric aspects of muscle activation. The results show how muscle fiber orientation and curvature change according to the direction of force generation, influencing the EMG signal, and provide new insights on how constitutive, anatomical and physiological properties contribute to shape motor unit action potentials detected at the skin surface.
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Affiliation(s)
- Diego Pereira Botelho
- School of Electrical and Electronic Engineering, University College Dublin, Belfield, Dublin, Ireland
| | - Kathleen Curran
- School of Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Madeleine M Lowery
- School of Electrical and Electronic Engineering, University College Dublin, Belfield, Dublin, Ireland
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Acer N, Turgut M. Evaluation of Brachial Plexus Using Combined Stereological Techniques of Diffusion Tensor Imaging and Fiber Tracking. J Brachial Plex Peripher Nerve Inj 2019; 14:e16-e23. [PMID: 31198435 PMCID: PMC6561765 DOI: 10.1055/s-0039-1687913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/18/2019] [Indexed: 02/03/2023] Open
Abstract
Background Brachial plexus (BP) is composed of intercommunications among the ventral roots of the nerves C5, C6, C7, C8, and T1 in the neck. The in vivo and in vitro evaluation of axons of the peripheral nervous system is performed using different techniques. Recently, many studies describing the application of fiber tractography and stereological axon number estimation to peripheral nerves have been published. Methods Various quantitative parameters of nerve fibers, including axon number, density, axonal area, and myelin thickness, can be estimated using stereological techniques. In vivo three-dimensional reconstruction of axons of BP can be visualized using a combined technique of diffusion tensor imaging (DTI) and fiber tracking with the potential to evaluate nerve fiber content. Conclusion It is concluded that terminal branches of BP can be successfully visualized using DTI, which is a highly reproducible method for the evaluation of BP as it shows anatomical and functional features of neural structures. We believe that quantitative morphological findings obtained from BP will be useful for new experimental, developmental, and pathological studies in the future.
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Affiliation(s)
- Niyazi Acer
- Department of Anatomy, Erciyes University School of Medicine, Kayseri, Turkey
| | - Mehmet Turgut
- Department of Neurosurgery, Adnan Menderes University School of Medicine, Aydın, Turkey
- Department of Histology and Embryology, Adnan Menderes University Health Sciences Institute, Aydın, Turkey
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