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Shanta T, Tomari YK, Higashi T, Madan B, Hosoyama H, Otsubo T, Yamahata H, Hanaya R. Hypometabolism in the Posteromedial Temporal and Medial Occipital Cortex on Preoperative 2-Deoxy-2-(18F) Fluoro-D-Glucose Positron Emission Tomography Suggests Exacerbation of Visual Field Defects After Surgery for Temporal Lobe Epilepsy: A Retrospective Long-Term Follow-Up Study. World Neurosurg 2024; 188:e223-e232. [PMID: 38777318 DOI: 10.1016/j.wneu.2024.05.089] [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: 03/30/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVE Surgery is a good treatment option for drug-resistant temporal lobe epilepsy (TLE). 2-deoxy-2-(18F) fluoro-D-glucose (FDG) positron emission tomography (PET) is used to detect epileptic foci as hypometabolic lesions in presurgical evaluation. Visual field defects (VFDs) in the contralateral homonymous upper quadrant are common postoperative complications in TLE. This study aimed to quantify VFDs using pattern deviation probability plots (PDPPs) and examine the effect of hypometabolism in FDG-PET on VFDs. METHODS This study included 40 patients. Both visual fields were assessed using the Humphrey field analyzer preoperatively and 3 months and 2 years postoperatively. PDPPs with <0.5% confidence level counted in the contralateral homonymous upper quadrant. FDG-PET results were compared between groups with (15 patients) and without (24 patients) hypometabolism in the optic radiation. RESULTS All 40 patients were evaluated by Humphrey field analyzer at 3 months postoperatively and 39 at 2 years postoperatively. The incidence of VFDs 3 months postoperatively was 35/40 (87.5%), and 17/40 (42.5%) patients had severe VFDs. In cases of surgery on the left temporal lobe, ipsilateral eyes appeared to be more significantly affected than contralateral eyes. VFDs were more severe in patients with FDG hypometabolism than in those without hypometabolism in posteromedial temporal and medial occipital cortex (P < 0.01); however, 85% of patients with FDG hypometabolism had a reduced VFD 2 years postoperatively. CONCLUSIONS PDPP counting is useful for quantifying VFDs. Preoperative dysfunction indicated by preoperative FDG-PET in the posteromedial temporal and medial occipital cortex could enhance VFDs early after TLE surgery.
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Affiliation(s)
- Thapa Shanta
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yumi Kashida Tomari
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Takuichiro Higashi
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Bajagain Madan
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hiroshi Hosoyama
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Toshiaki Otsubo
- Department of Neurosurgery, Fujimoto General Hospital, Miyakonojo, Kagoshima, Japan
| | - Hitoshi Yamahata
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ryosuke Hanaya
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
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Herlin B, Uszynski I, Chauvel M, Poupon C, Dupont S. Cross-subject variability of the optic radiation anatomy in a cohort of 1065 healthy subjects. Surg Radiol Anat 2023:10.1007/s00276-023-03161-4. [PMID: 37195302 DOI: 10.1007/s00276-023-03161-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/28/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Optic radiations are tracts of particular interest for neurosurgery, especially for temporal lobe resection, because their lesion is responsible for visual field defects. However, histological and MRI studies found a high inter-subject variability of the optic radiation anatomy, especially for their most rostral extent inside the Meyer's temporal loop. We aimed to better assess inter-subject anatomical variability of the optic radiations, in order to help to reduce the risk of postoperative visual field deficiencies. METHODS Using an advanced analysis pipeline relying on a whole-brain probabilistic tractography and fiber clustering, we processed the diffusion MRI data of the 1065 subjects of the HCP cohort. After registration in a common space, a cross-subject clustering on the whole cohort was performed to reconstruct the reference optic radiation bundle, from which all optic radiations were segmented on an individual scale. RESULTS We found a median distance between the rostral tip of the temporal pole and the rostral tip of the optic radiation of 29.2 mm (standard deviation: 2.1 mm) for the right side and 28.8 mm (standard deviation: 2.3 mm) for the left side. The difference between both hemispheres was statistically significant (p = 1.10-8). CONCLUSION We demonstrated inter-individual variability of the anatomy of the optic radiations on a large-scale study, especially their rostral extension. In order to better guide neurosurgical procedures, we built a MNI-based reference atlas of the optic radiations that can be used for fast optic radiation reconstruction from any individual diffusion MRI tractography.
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Affiliation(s)
- B Herlin
- BAOBAB, NeuroSpin, Université Paris-Saclay, CNRS, CEA, Gif-Sur-Yvette, France.
- AP-HP, Epilepsy Unit, GH Pitié-Salpêtrière-Charles Foix, 47-83 Boulevard de L'Hôpital, 75013, Paris, France.
- Sorbonne Université, Paris, France.
| | - I Uszynski
- BAOBAB, NeuroSpin, Université Paris-Saclay, CNRS, CEA, Gif-Sur-Yvette, France
| | - M Chauvel
- BAOBAB, NeuroSpin, Université Paris-Saclay, CNRS, CEA, Gif-Sur-Yvette, France
| | - C Poupon
- BAOBAB, NeuroSpin, Université Paris-Saclay, CNRS, CEA, Gif-Sur-Yvette, France
| | - S Dupont
- AP-HP, Epilepsy Unit, GH Pitié-Salpêtrière-Charles Foix, 47-83 Boulevard de L'Hôpital, 75013, Paris, France
- Sorbonne Université, Paris, France
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Pruckner P, Nenning KH, Fischmeister FPS, Yildirim MS, Schwarz M, Reitner A, Aull-Watschinger S, Koren J, Baumgartner C, Prayer D, Rössler K, Dorfer C, Czech T, Pataraia E, Kasprian G, Bonelli S. Visual outcomes after anterior temporal lobectomy and transsylvian selective amygdalohippocampectomy: A quantitative comparison of clinical and diffusion data. Epilepsia 2023; 64:705-717. [PMID: 36529714 DOI: 10.1111/epi.17490] [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: 07/26/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Anterior temporal lobectomy (ATL) and transsylvian selective amygdalohippocampectomy (tsSAHE) are effective treatment strategies for intractable temporal lobe epilepsy but may cause visual field deficits (VFDs) by damaging the optic radiation (OpR). Due to the OpR's considerable variability and because it is indistinguishable from surrounding tissue without further technical guidance, it is highly vulnerable to iatrogenic injury. This imaging study uses a multimodal approach to assess visual outcomes after epilepsy surgery. METHODS We studied 62 patients who underwent ATL (n = 32) or tsSAHE (n = 30). Analysis of visual outcomes was conducted in four steps, including the assessment of (1) perimetry outcome (VFD incidence/extent, n = 44/40), (2) volumetric OpR tractography damage (n = 55), and the (3) relation of volumetric OpR tractography damage and perimetry outcome (n = 35). Furthermore, (4) fixel-based analysis (FBA) was performed to assess micro- and macrostructural changes within the OpR following surgery (n = 36). RESULTS Altogether, 56% of all patients had postoperative VFDs (78.9% after ATL, 36.36% after tsSAHE, p = .011). VFDs and OpR tractography damage tended to be more severe within the ATL group (ATL vs. tsSAHE, integrity of contralateral upper quadrant: 65% vs. 97%, p = .002; OpR tractography damage: 69.2 mm3 vs. 3.8 mm3 , p = .002). Volumetric OpR tractography damage could reliably predict VFD incidence (86% sensitivity, 78% specificity) and could significantly explain VFD extent (R2 = .47, p = .0001). FBA revealed a more widespread decline of fibre cross-section within the ATL group. SIGNIFICANCE In the context of controversial visual outcomes following epilepsy surgery, this study provides clinical as well as neuroimaging evidence for a higher risk and greater severity of postoperative VFDs after ATL compared to tsSAHE. Volumetric OpR tractography damage is a feasible parameter to reliably predict this morbidity in both treatment groups and may ultimately support personalized planning of surgical candidates. Advanced diffusion analysis tools such as FBA offer a structural explanation of surgically induced visual pathway damage, allowing noninvasive quantification and visualization of micro- and macrostructural tract affection.
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Affiliation(s)
- Philip Pruckner
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Karl-Heinz Nenning
- Computational Imaging Research Lab, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute, Orangeburg, New York, USA
| | - Florian Ph S Fischmeister
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Institute of Psychology, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Mehmet-Salih Yildirim
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Michelle Schwarz
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Andreas Reitner
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | | | - Johannes Koren
- Department of Neurology, Clinic Hietzing, Vienna, Austria
| | - Christoph Baumgartner
- Department of Neurology, Clinic Hietzing, Vienna, Austria
- Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria
- Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - Daniela Prayer
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Karl Rössler
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Christian Dorfer
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Thomas Czech
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | | | - Gregor Kasprian
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Silvia Bonelli
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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Iqbal S, Leon-Rojas JE, Galovic M, Vos SB, Hammers A, de Tisi J, Koepp MJ, Duncan JS. Volumetric analysis of the piriform cortex in temporal lobe epilepsy. Epilepsy Res 2022; 185:106971. [PMID: 35810570 PMCID: PMC10510027 DOI: 10.1016/j.eplepsyres.2022.106971] [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: 08/31/2021] [Revised: 05/13/2022] [Accepted: 06/22/2022] [Indexed: 11/03/2022]
Abstract
The piriform cortex, at the confluence of the temporal and frontal lobes, generates seizures in response to chemical convulsants and electrical stimulation. Resection of more than 50% of the piriform cortex in anterior temporal lobe resection for refractory temporal lobe epilepsy (TLE) was associated with a 16-fold higher chance of seizure freedom. The objectives of the current study were to implement a robust protocol to measure piriform cortex volumes and to quantify the correlation of these volumes with clinical characteristics of TLE. Sixty individuals with unilateral TLE (33 left) and 20 healthy controls had volumetric analysis of left and right piriform cortex and hippocampi. A protocol for segmenting and measuring the volumes of the piriform cortices was implemented, with good inter-rater and test-retest reliability. The right piriform cortex volume was consistently larger than the left piriform cortex in both healthy controls and patients with TLE. In controls, the mean volume of the right piriform cortex was 17.7% larger than the left, and the right piriform cortex extended a mean of 6 mm (Range: -4 to 12) more anteriorly than the left. This asymmetry was also seen in left and right TLE. In TLE patients overall, the piriform cortices were not significantly smaller than in controls. Hippocampal sclerosis was associated with decreased ipsilateral and contralateral piriform cortex volumes. The piriform cortex volumes, both ipsilateral and contralateral to the epileptic temporal lobe, were smaller with a longer duration of epilepsy. There was no significant association between piriform cortex volumes and the frequency of focal seizures with impaired awareness or the number of anti-seizure medications taken. Implementation of robust segmentation will enable consistent neurosurgical resection in anterior temporal lobe surgery for refractory TLE..
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Affiliation(s)
- Sabahat Iqbal
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Jose E Leon-Rojas
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, Buckinghamshire, United Kingdom; Facultad de Ciencias Médicas de la Salud y de la Vida, Escuela de Medicina, Universidad Internacional del Ecuador, Quito, Ecuador
| | - Marian Galovic
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, Buckinghamshire, United Kingdom; Department of Neurology, Zurich University Hospital, Zurich, Switzerland
| | - Sjoerd B Vos
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Centre for Medical Image Computing (CMIC), Department of Computer Science, University College London, United Kingdom; Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Alexander Hammers
- School of Biomedical Engineering and Imaging Sciences, Kings College, London, United Kingdom; Kings College London & Guys and St Thomas' PET Centre at St. Thomas' Hospital, United Kingdom
| | - Jane de Tisi
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Matthias J Koepp
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - John S Duncan
- UK National Institute for Health Research University College London Hospitals Biomedical Research Centre, and Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom; Epilepsy Society MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, Buckinghamshire, United Kingdom.
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Abstract
Temporal lobe epilepsy (TLE) is the most common cause of refractory epilepsy amenable for surgical treatment and seizure control. Surgery for TLE is a safe and effective strategy. The seizure-free rate after surgical resection in patients with mesial or neocortical TLE is about 70%. Resective surgery has an advantage over stereotactic radiosurgery in terms of seizure outcomes for mesial TLE patients. Both techniques have similar results for safety, cognitive outcomes, and associated costs. Stereotactic radiosurgery should therefore be seen as an alternative to open surgery for patients with contraindications for or with reluctance to undergo open surgery. Laser interstitial thermal therapy (LITT) has also shown promising results as a curative technique in mesial TLE but needs to be more deeply evaluated. Brain-responsive stimulation represents a palliative treatment option for patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior mesial temporal lobe resection. Overall, despite the expansion of innovative techniques in recent years, resective surgery remains the reference treatment for TLE and should be proposed as the first-line surgical modality. In the future, ultrasound therapies could become a credible therapeutic option for refractory TLE patients.
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Affiliation(s)
- Bertrand Mathon
- Department of Neurosurgery, La Pitié-Salpêtrière University Hospital, Paris, France; Sorbonne University, Paris, France; Paris Brain Institute, Paris, France
| | - Stéphane Clemenceau
- Department of Neurosurgery, La Pitié-Salpêtrière University Hospital, Paris, France
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Reid LB, Martínez‐Heras E, Manjón JV, Jeffree RL, Alexander H, Trinder J, Solana E, Llufriu S, Rose S, Prior M, Fripp J. Fully automated delineation of the optic radiation for surgical planning using clinically feasible sequences. Hum Brain Mapp 2021; 42:5911-5926. [PMID: 34547147 PMCID: PMC8596983 DOI: 10.1002/hbm.25658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/21/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022] Open
Abstract
Quadrantanopia caused by inadvertent severing of Meyer's Loop of the optic radiation is a well-recognised complication of temporal lobectomy for conditions such as epilepsy. Dissection studies indicate that the anterior extent of Meyer's Loop varies considerably between individuals. Quantifying this for individual patients is thus an important step to improve the safety profile of temporal lobectomies. Previous attempts to delineate Meyer's Loop using diffusion MRI tractography have had difficulty estimating its full anterior extent, required manual ROI placement, and/or relied on advanced diffusion sequences that cannot be acquired routinely in most clinics. Here we present CONSULT: a pipeline that can delineate the optic radiation from raw DICOM data in a completely automated way via a combination of robust pre-processing, segmentation, and alignment stages, plus simple improvements that bolster the efficiency and reliability of standard tractography. We tested CONSULT on 696 scans of predominantly healthy participants (539 unique brains), including both advanced acquisitions and simpler acquisitions that could be acquired in clinically acceptable timeframes. Delineations completed without error in 99.4% of the scans. The distance between Meyer's Loop and the temporal pole closely matched both averages and ranges reported in dissection studies for all tested sequences. Median scan-rescan error of this distance was 1 mm. When tested on two participants with considerable pathology, delineations were successful and realistic. Through this, we demonstrate not only how to identify Meyer's Loop with clinically feasible sequences, but also that this can be achieved without fundamental changes to tractography algorithms or complex post-processing methods.
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Affiliation(s)
- Lee B. Reid
- The Australian e‐Health Research CentreCSIROBrisbaneQueenslandAustralia
| | - Eloy Martínez‐Heras
- Center of Neuroimmunology, Laboratory of Advanced Imaging in Neuroimmunological Diseases (ImaginEM), Hospital Clinic BarcelonaInstitut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS) and Universitat de BarcelonaBarcelonaSpain
| | - Jose V. Manjón
- Instituto de Aplicaciones de las Tecnologías de la Información y de las Comunicaciones Avanzadas (ITACA), Universitat Politècnica de ValènciaValenciaSpain
| | - Rosalind L. Jeffree
- Royal Brisbane and Women's HospitalMetro NorthQueenslandAustralia
- School of Clinical MedicineUniversity of QueenslandHerstonQueenslandAustralia
| | - Hamish Alexander
- Royal Brisbane and Women's HospitalMetro NorthQueenslandAustralia
| | - Julie Trinder
- The Australian e‐Health Research CentreCSIROBrisbaneQueenslandAustralia
| | - Elisabeth Solana
- Center of Neuroimmunology, Laboratory of Advanced Imaging in Neuroimmunological Diseases (ImaginEM), Hospital Clinic BarcelonaInstitut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS) and Universitat de BarcelonaBarcelonaSpain
| | - Sara Llufriu
- Center of Neuroimmunology, Laboratory of Advanced Imaging in Neuroimmunological Diseases (ImaginEM), Hospital Clinic BarcelonaInstitut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS) and Universitat de BarcelonaBarcelonaSpain
| | - Stephen Rose
- The Australian e‐Health Research CentreCSIROBrisbaneQueenslandAustralia
| | - Marita Prior
- Royal Brisbane and Women's HospitalMetro NorthQueenslandAustralia
| | - Jurgen Fripp
- The Australian e‐Health Research CentreCSIROBrisbaneQueenslandAustralia
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de Souza JPSAS, Ayub G, Nogueira M, Zanao T, Lopes TM, Pimentel-Silva LR, Domene V, Marquez G, Yasuda CL, Ribeiro LF, Campos BM, Vasconcellos J, Rogerio F, Joaquim AF, Cendes F, Tedeschi H, Ghizoni E. Temporopolar amygdalohippocampectomy: seizure control and postoperative outcomes. J Neurosurg 2021; 134:1044-1053. [PMID: 32413857 DOI: 10.3171/2020.3.jns192624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/10/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The objective of this study was to evaluate the efficacy and safety of a modified surgical approach for the treatment of temporal lobe epilepsy secondary to hippocampal sclerosis (HS). This modified approach, called temporopolar amygdalohippocampectomy (TP-AH), includes a transsylvian resection of the temporal pole and subsequent amygdalohippocampectomy utilizing the limen insula as an anatomical landmark. METHODS A total of 61 patients who were diagnosed with HS and underwent TP-AH between 2013 and 2017 were enrolled. Patients performed pre- and postoperative diffusion tensor imaging and were classified according to Engel's scale for seizure control. To evaluate the functional preservation of the temporal stem white-matter fiber tracts, the authors analyzed postoperative Humphrey perimetries and pre- and postoperative neurocognitive performance (Rey Auditory Verbal Learning Test [RAVLT], Weschler Memory Scale-Revised [WMS-R], intelligence quotient [IQ], Boston Naming Test [BNT], and semantic and phonemic fluency). Demographic data and surgical complications were also recorded and described. RESULTS After a median follow-up of 36 ± 16 months, 46 patients (75.4%) achieved Engel class I, of whom 37 (60.6%) were Engel class IA. No significant changes in either the inferior frontooccipital fasciculus and optic radiation tractography were observed postoperatively for both left- and right-side surgeries. Reliable perimetry was obtained in 40 patients (65.6%), of whom 27 (67.5%) did not present any visual field defects (VFDs) attributable to surgery, while 12 patients (30%) presented with quadrant VFD, and 1 patient (2.5%) presented with hemifield VFD. Despite a significant decline in verbal memory (p = 0.007 for WMS-R, p = 0.02 for RAVLT recognition), there were significant improvements in both IQ (p < 0.001) and visual memory (p = 0.007). Semantic and phonemic fluency, and scores on the BNT, did not change postoperatively. CONCLUSIONS TP-AH provided seizure control similar to historical temporal lobe approaches, with a tendency to preserve the temporal stem and a satisfactory incidence of VFD. Despite a significant decline in verbal memory, there were significant improvements in both IQ and visual memory, along with preservation of executive function. This approach can be considered a natural evolution of the selective transsylvian approach.
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Affiliation(s)
| | | | | | - Tamires Zanao
- 1Neuroimaging Laboratory (LNI), Department of Neurology
| | | | | | | | | | | | | | | | | | - Fabio Rogerio
- 5Department of Anatomical Pathology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | - Fernando Cendes
- 1Neuroimaging Laboratory (LNI), Department of Neurology
- 3Clinical Neurology
| | | | - Enrico Ghizoni
- 1Neuroimaging Laboratory (LNI), Department of Neurology
- Divisions of2Neurosurgery and
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8
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Honnedevasthana Arun A, Connelly A, Smith RE, Calamante F. Characterisation of white matter asymmetries in the healthy human brain using diffusion MRI fixel-based analysis. Neuroimage 2020; 225:117505. [PMID: 33147511 DOI: 10.1016/j.neuroimage.2020.117505] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/18/2020] [Accepted: 10/22/2020] [Indexed: 12/13/2022] Open
Abstract
The diffusion tensor model for diffusion MRI has been used extensively to study asymmetry in the human brain white matter. However, given the limitations of the tensor model, the nature of any underlying asymmetries remains uncertain, particularly in crossing fibre regions. Here, we provide a more robust characterisation of human brain white matter asymmetries based on fibre-specific diffusion MRI metrics and a whole-brain data-driven approach. We used high-quality diffusion MRI data (n = 100) from the Human Connectome Project, the spherical deconvolution model for fibre orientation distribution estimation, and the Fixel-Based Analysis framework to utilise crossing fibre information in registration, data smoothing and statistical inference. We found many significant asymmetries, widespread throughout the brain white matter, with both left>right and right>left dominances observed in different pathways. No influences of sex, age, or handedness on asymmetry were found. We also report on the relative contributions of microstructural and morphological white matter properties toward the asymmetry findings. Our findings should provide important information to future studies focussing on how these asymmetries are affected by disease, development/ageing, or how they correlate to functional/cognitive measures.
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Affiliation(s)
- Arush Honnedevasthana Arun
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; The University of Sydney, School of Biomedical Engineering, Sydney, Australia
| | - Alan Connelly
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Robert E Smith
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Fernando Calamante
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; The University of Sydney, Sydney Imaging, Sydney, Australia; The University of Sydney, School of Biomedical Engineering, Sydney, Australia.
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9
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Jacqmot O, Van Thielen B, Michotte A, de Mey J, Provyn S, Tresignie J. Neuroanatomical Reconstruction of the Canine Visual Pathway Using Diffusion Tensor Imaging. Front Neuroanat 2020; 14:54. [PMID: 32973464 PMCID: PMC7461977 DOI: 10.3389/fnana.2020.00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/28/2020] [Indexed: 11/13/2022] Open
Abstract
The first anatomical atlas of diffusion tensor imaging (DTI) of white matter pathways in the canine brain was published in 2013; however, the anatomical orientation of the entire visual pathway in the canine brain, from the retina to the cortex, has not yet been studied using DTI. In the present study, 3T DTI magnetic resonance (MR) images of three dogs euthanized for reasons other than neurological disorders were obtained. The process of obtaining combined fractional anisotropy and directional maps was initiated within 1 h of death. The heads were amputated immediately after MR imaging and stored in 10% formalin until dissection and histological sampling was performed. The trajectory of the visual pathway is dissimilar to the horizontal representation in other literature. To our knowledge, ours is the first study to visualize the entire canine visual pathway in its full antero-posterior extension. Fibers from the retina to the cortex passed through the optic nerve, optic chiasm, optic tracts, lateral geniculate nucleus, Meyer’s and Baum’s loops, and pretectal fibers. Their projections to the cortex were similar to those in the human visual pathway. The crossing of fibers at the optic chiasm occurred in 75% of fibers. In addition to advancing our knowledge in this field of study, these results could help plan neurosurgical and radiotherapeutic procedures to avoid unnecessary damage to the visual fiber system.
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Affiliation(s)
- Olivier Jacqmot
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium.,MOVE-HIM (Morpho Veterinary and Human Imaging) Brussels, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Bert Van Thielen
- MOVE-HIM (Morpho Veterinary and Human Imaging) Brussels, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium.,Department of Radiology, UZ Brussel, Brussels, Belgium.,Odisee Brussel, Educational Department for Imaging Technologists, Brussels, Belgium.,Anatomical Research, Training and Education (ARTE), Vrije Universiteit Brussel, Brussels, Belgium
| | - Alex Michotte
- Department of Neurology and Neuropathology, Neuroanatomy, UZ Brussel, Brussels, Belgium
| | - Johan de Mey
- Department of Radiology, UZ Brussel, Brussels, Belgium
| | - Steven Provyn
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium
| | - Jonathan Tresignie
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium
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Lacerda LM, Clayden JD, Handley SE, Winston GP, Kaden E, Tisdall M, Cross JH, Liasis A, Clark CA. Microstructural Investigations of the Visual Pathways in Pediatric Epilepsy Neurosurgery: Insights From Multi-Shell Diffusion Magnetic Resonance Imaging. Front Neurosci 2020; 14:269. [PMID: 32322185 PMCID: PMC7158873 DOI: 10.3389/fnins.2020.00269] [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: 01/13/2020] [Accepted: 03/10/2020] [Indexed: 01/12/2023] Open
Abstract
Background Surgery is a key approach for achieving seizure freedom in children with focal onset epilepsy. However, the resection can affect or be in the vicinity of the optic radiations. Multi-shell diffusion MRI and tractography can better characterize tissue structure and provide guidance to help minimize surgical related deficits. Whilst in adults tractography has been used to demonstrate that damage to the optic radiations leads to postoperative visual field deficits, this approach has yet to be properly explored in children. Objective To demonstrate the capabilities of multi-shell diffusion MRI and tractography in characterizing microstructural changes in children with epilepsy pre- and post-surgery affecting the occipital, parietal or temporal lobes. Methods Diffusion Tensor Imaging and the Spherical Mean Technique were used to investigate the microstructure of the optic radiations. Furthermore, tractography was used to evaluate whether pre-surgical reconstructions of the optic radiations overlap with the resection margin as measured using anatomical post-surgical T1-weighted MRI. Results Increased diffusivity in patients compared to controls at baseline was observed with evidence of decreased diffusivity, anisotropy, and neurite orientation distribution in contralateral hemisphere after surgery. Pre-surgical optic radiation tractography overlapped with post-surgical resection margins in 20/43 (46%) children, and where visual data was available before and after surgery, the presence of overlap indicated a visual field deficit. Conclusion This is the first report in a pediatric series which highlights the relevance of tractography for future pre-surgical evaluation in children undergoing epilepsy surgery and the usefulness of multi-shell diffusion MRI to characterize brain microstructure in these patients.
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Affiliation(s)
- Luís M Lacerda
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Jonathan D Clayden
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Sian E Handley
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Gavin P Winston
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,Division of Neurology, Department of Medicine, Queen's University, Kingston, ON, Canada
| | - Enrico Kaden
- Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Martin Tisdall
- Department of Neurosurgery, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - J Helen Cross
- Clinical Neurosciences, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Alki Liasis
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Children's Hospital of Pittsburgh, University of Pittsburgh Medical Centre, Pittsburgh, PA, United States
| | - Chris A Clark
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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Fractional anisotropy of the optic radiations correlates with the visual field after epilepsy surgery. Neuroradiology 2019; 61:1425-1436. [DOI: 10.1007/s00234-019-02281-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/14/2019] [Indexed: 11/26/2022]
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12
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Bertani GA, Bertulli L, Scola E, Di Cristofori A, Zavanone M, Triulzi F, Rampini PM, Carrabba GG. Optic Radiation Diffusion Tensor Imaging Tractography: An Alternative and Simple Technique for the Accurate Detection of Meyer's Loop. World Neurosurg 2018; 117:e42-e56. [DOI: 10.1016/j.wneu.2018.05.131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/11/2022]
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Chamberland M, Tax CMW, Jones DK. Meyer's loop tractography for image-guided surgery depends on imaging protocol and hardware. Neuroimage Clin 2018; 20:458-465. [PMID: 30128284 PMCID: PMC6096050 DOI: 10.1016/j.nicl.2018.08.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/31/2018] [Accepted: 08/10/2018] [Indexed: 12/19/2022]
Abstract
Introduction Surgical resection is an effective treatment for temporal lobe epilepsy but can result in visual field defects. This could be minimized if surgeons knew the exact location of the anterior part of the optic radiation (OR), the Meyer's loop. To this end, there is increasing prevalence of image-guided surgery using diffusion MRI tractography. Despite considerable effort in developing analysis methods, a wide discrepancy in Meyer's loop reconstructions is observed in the literature. Moreover, the impact of differences in image acquisition on Meyer's loop tractography remains unclear. Here, while employing the same state-of-the-art analysis protocol, we explored the extent to which variance in data acquisition leads to variance in OR reconstruction. Methods Diffusion MRI data were acquired for the same thirteen healthy subjects using standard and state-of-the-art protocols on three scanners with different maximum gradient amplitudes (MGA): Siemens Connectom (MGA = 300 mT/m); Siemens Prisma (MGA = 80 mT/m) and GE Excite-HD (MGA = 40 mT/m). Meyer's loop was reconstructed on all subjects and its distance to the temporal pole (ML-TP) was compared across protocols. Results A significant effect of data acquisition on the ML-TP distance was observed between protocols (p < .01 to 0.0001). The biggest inter-acquisition discrepancy for the same subject across different protocols was 16.5 mm (mean: 9.4 mm, range: 3.7-16.5 mm). Conclusion We showed that variance in data acquisition leads to substantive variance in OR tractography. This has direct implications for neurosurgical planning, where part of the OR is at risk due to an under-estimation of its location using conventional acquisition protocols.
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Affiliation(s)
- Maxime Chamberland
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom.
| | - Chantal M W Tax
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom
| | - Derek K Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom; School of Psychology, Faculty of Health Sciences, Australian Catholic University, Victoria, Australia
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Wang C, Klistorner A, Ly L, Barnett MH. White matter tract-specific quantitative analysis in multiple sclerosis: Comparison of optic radiation reconstruction techniques. PLoS One 2018; 13:e0191131. [PMID: 29342192 PMCID: PMC5771610 DOI: 10.1371/journal.pone.0191131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 12/28/2017] [Indexed: 11/23/2022] Open
Abstract
The posterior visual pathway is commonly affected by multiple sclerosis (MS) pathology that results in measurable clinical and electrophysiological impairment. Due to its highly structured retinotopic mapping, the visual pathway represents an ideal substrate for investigating patho-mechanisms in MS. Therefore, a reliable and robust imaging segmentation method for in-vivo delineation of the optic radiations (OR) is needed. However, diffusion-based tractography approaches, which are typically used for OR segmentation are confounded by the presence of focal white matter lesions. Current solutions require complex acquisition paradigms and demand expert image analysis, limiting application in both clinical trials and clinical practice. In the current study, using data acquired in a clinical setting on a 3T scanner, we optimised and compared two approaches for optic radiation (OR) reconstruction: individual probabilistic tractography-based and template-based methods. OR segmentation results were applied to subjects with MS and volumetric and diffusivity parameters were compared between OR segmentation techniques. Despite differences in reconstructed OR volumes, both OR lesion volume and OR diffusivity measurements in MS subjects were highly comparable using optimised probabilistic tractography-based, and template-based, methods. The choice of OR reconstruction technique should be determined primarily by the research question and the nature of the available dataset. Template-based approaches are particularly suited to the semi-automated analysis of large image datasets and have utility even in the absence of dMRI acquisitions. Individual tractography methods, while more complex than template based OR reconstruction, permit measurement of diffusivity changes along fibre bundles that are affected by specific MS lesions or other focal pathologies.
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Affiliation(s)
- Chenyu Wang
- Sydney Neuroimaging Analysis Centre, Sydney, New South Wales, Australia
- Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Alexander Klistorner
- Sydney Neuroimaging Analysis Centre, Sydney, New South Wales, Australia
- Department of Ophthalmology, Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Linda Ly
- Sydney Neuroimaging Analysis Centre, Sydney, New South Wales, Australia
- Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Michael H. Barnett
- Sydney Neuroimaging Analysis Centre, Sydney, New South Wales, Australia
- Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Schmeiser B, Daniel M, Kogias E, Böhringer D, Egger K, Yang S, Foit NA, Schulze-Bonhage A, Steinhoff BJ, Zentner J, Lagrèze WA, Gross NJ. Visual field defects following different resective procedures for mesiotemporal lobe epilepsy. Epilepsy Behav 2017; 76:39-45. [PMID: 28954709 DOI: 10.1016/j.yebeh.2017.08.037] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/15/2017] [Accepted: 08/26/2017] [Indexed: 10/18/2022]
Abstract
INTRODUCTION One of the most common side effects of mesiotemporal lobe resection in patients with medically intractable epilepsy are visual field defects (VFD). While peripheral defects usually remain unnoticed by patients, extended VFD influence daily life activities and can, in particular, affect driving regulations. This study had been designed to evaluate frequency and extent of VFD following different surgical approaches to the mesiotemporal area with respect to the ability to drive. MATERIALS AND METHODS This study comprises a consecutive series of 366 patients operated at the Epilepsy Center in Freiburg for intractable mesiotemporal lobe epilepsy from 1998 to 2016. The following procedures were performed: standard anterior temporal lobectomy (ATL: n=134; 37%), anterior temporal or keyhole resection (KH: n=53; 15%), and selective amygdalohippocampectomy via the transsylvian (tsAHE: n=145; 40%) and the subtemporal (ssAHE: n=34; 9%) approach. Frequency and extent of postoperative VFD were evaluated in relation to different surgical procedures. According to the German driving guidelines, postoperative VFD were classified as driving-relevant VFD with the involvement of absolute, homonymous central scotoma within 20° and driving-irrelevant VFD with either none or exclusively minor VFD sparing the center. RESULTS Postoperative visual field examinations were available in 276 of 366 cases. Postoperative VFD were observed in 202 of 276 patients (73%) and were found to be driving-relevant in 133 of 276 patients (48%), whereas 69 patients (25%) showed VFD irrelevant for driving. Visual field defects were significantly less likely following ssAHE compared with other temporal resections, and if present, they were less frequently driving-relevant (p<0.05), irrespective of the side of surgery. CONCLUSION Subtemporal sAHE (ssAHE) caused significantly less frequently and less severely driving-relevant VFD compared with all other approaches to the temporal lobe, irrespective of the side of surgery.
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Affiliation(s)
- Barbara Schmeiser
- Department of Neurosurgery, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany.
| | - Moritz Daniel
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Trust and UCL Institute of Ophthalmology, London, United Kingdom; Eye Center, Medical Center - University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Evangelos Kogias
- Department of Neurosurgery, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Daniel Böhringer
- Eye Center, Medical Center - University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Karl Egger
- Department of Neuroradiology, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Shan Yang
- Department of Neuroradiology, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Niels Alexander Foit
- Department of Neurosurgery, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Andreas Schulze-Bonhage
- Department of Epileptology, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | | | - Josef Zentner
- Department of Neurosurgery, Medical Center - University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Wolf Alexander Lagrèze
- Eye Center, Medical Center - University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Nikolai Johannes Gross
- Eye Center, Medical Center - University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
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Shi Y, Toga AW. Connectome imaging for mapping human brain pathways. Mol Psychiatry 2017; 22:1230-1240. [PMID: 28461700 PMCID: PMC5568931 DOI: 10.1038/mp.2017.92] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/06/2017] [Accepted: 02/24/2017] [Indexed: 01/23/2023]
Abstract
With the fast advance of connectome imaging techniques, we have the opportunity of mapping the human brain pathways in vivo at unprecedented resolution. In this article we review the current developments of diffusion magnetic resonance imaging (MRI) for the reconstruction of anatomical pathways in connectome studies. We first introduce the background of diffusion MRI with an emphasis on the technical advances and challenges in state-of-the-art multi-shell acquisition schemes used in the Human Connectome Project. Characterization of the microstructural environment in the human brain is discussed from the tensor model to the general fiber orientation distribution (FOD) models that can resolve crossing fibers in each voxel of the image. Using FOD-based tractography, we describe novel methods for fiber bundle reconstruction and graph-based connectivity analysis. Building upon these novel developments, there have already been successful applications of connectome imaging techniques in reconstructing challenging brain pathways. Examples including retinofugal and brainstem pathways will be reviewed. Finally, we discuss future directions in connectome imaging and its interaction with other aspects of brain imaging research.
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Affiliation(s)
- Y Shi
- Laboratory of Neuro Imaging (LONI), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - A W Toga
- Laboratory of Neuro Imaging (LONI), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Complications After Surgery for Mesial Temporal Lobe Epilepsy Associated with Hippocampal Sclerosis. World Neurosurg 2017; 102:639-650.e2. [DOI: 10.1016/j.wneu.2017.03.128] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 03/26/2017] [Accepted: 03/27/2017] [Indexed: 01/03/2023]
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18
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Muzumdar D, Patil M, Goel A, Ravat S, Sawant N, Shah U. Mesial temporal lobe epilepsy – An overview of surgical techniques. Int J Surg 2016; 36:411-419. [DOI: 10.1016/j.ijsu.2016.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 12/29/2022]
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Nowell M, Vos SB, Sidhu M, Wilcoxen K, Sargsyan N, Ourselin S, Duncan JS. Meyer's loop asymmetry and language lateralisation in epilepsy. J Neurol Neurosurg Psychiatry 2016; 87:836-42. [PMID: 26384513 PMCID: PMC4975828 DOI: 10.1136/jnnp-2015-311161] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/01/2015] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation. METHODS 57 patients with epilepsy were identified with language functional MRI (fMRI) and diffusion MRI acquisition. Language lateralisation indices from fMRI(LI) and optic radiation and arcuate fasciculus probabilistic tractography was performed for each subject. The subjects were divided into left language dominant (LI>0.4) and non-left language groups (LI<0.4) according to their LI. RESULTS A negative linear correlation was identified between language lateralisation and MLA, with greater left lateralised language associated with more anteriorly placed left Meyer's loops (R value -0.34, p=0.01). There was a significant difference in mean MLA between the two groups, with the left loop being anterior to the right loop in the LI>0.4 group and posterior to the right loop in the LI<0.4 group (p=0.003). No correlation was found between language lateralisation and arcuate fasciculus volume. CONCLUSIONS This study suggests an association between the extent of Meyer's loop asymmetry and the lateralisation of language determined by fMRI in patients with epilepsy. Further studies should be carried out to evaluate this association in control subjects and with other measures of language lateralisation.
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Affiliation(s)
- Mark Nowell
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK
| | - Sjoerd B Vos
- MRI Unit, Epilepsy Society, Chalfont St Peter, UK Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK
| | - Meneka Sidhu
- MRI Unit, Epilepsy Society, Chalfont St Peter, UK
| | | | | | - Sebastien Ourselin
- Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK
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Renauld E, Descoteaux M, Bernier M, Garyfallidis E, Whittingstall K. Semi-Automatic Segmentation of Optic Radiations and LGN, and Their Relationship to EEG Alpha Waves. PLoS One 2016; 11:e0156436. [PMID: 27383146 PMCID: PMC4934857 DOI: 10.1371/journal.pone.0156436] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/13/2016] [Indexed: 12/13/2022] Open
Abstract
At rest, healthy human brain activity is characterized by large electroencephalography (EEG) fluctuations in the 8-13 Hz range, commonly referred to as the alpha band. Although it is well known that EEG alpha activity varies across individuals, few studies have investigated how this may be related to underlying morphological variations in brain structure. Specifically, it is generally believed that the lateral geniculate nucleus (LGN) and its efferent fibres (optic radiation, OR) play a key role in alpha activity, yet it is unclear whether their shape or size variations contribute to its inter-subject variability. Given the widespread use of EEG alpha in basic and clinical research, addressing this is important, though difficult given the problems associated with reliably segmenting the LGN and OR. For this, we employed a multi-modal approach and combined diffusion magnetic resonance imaging (dMRI), functional magnetic resonance imaging (fMRI) and EEG in 20 healthy subjects to measure structure and function, respectively. For the former, we developed a new, semi-automated approach for segmenting the OR and LGN, from which we extracted several structural metrics such as volume, position and diffusivity. Although these measures corresponded well with known morphology based on previous post-mortem studies, we nonetheless found that their inter-subject variability was not significantly correlated to alpha power or peak frequency (p >0.05). Our results therefore suggest that alpha variability may be mediated by an alternative structural source and our proposed methodology may in general help in better understanding the influence of anatomy on function such as measured by EEG or fMRI.
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Affiliation(s)
- Emmanuelle Renauld
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Maxime Descoteaux
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Faculty of Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Qc, Canada
- Centre d’Imagerie Moléculaire de Sherbrooke (CIMS), Centre de Recherche du CHUS, Sherbrooke, Qc, Canada
| | - Michaël Bernier
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Eleftherios Garyfallidis
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Faculty of Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Kevin Whittingstall
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Department of Diagnostic Radiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Qc, Canada
- Centre d’Imagerie Moléculaire de Sherbrooke (CIMS), Centre de Recherche du CHUS, Sherbrooke, Qc, Canada
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Automated retinofugal visual pathway reconstruction with multi-shell HARDI and FOD-based analysis. Neuroimage 2015; 125:767-779. [PMID: 26551261 DOI: 10.1016/j.neuroimage.2015.11.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 09/22/2015] [Accepted: 11/03/2015] [Indexed: 12/30/2022] Open
Abstract
Diffusion MRI tractography provides a non-invasive modality to examine the human retinofugal projection, which consists of the optic nerves, optic chiasm, optic tracts, the lateral geniculate nuclei (LGN) and the optic radiations. However, the pathway has several anatomic features that make it particularly challenging to study with tractography, including its location near blood vessels and bone-air interface at the base of the cerebrum, crossing fibers at the chiasm, somewhat-tortuous course around the temporal horn via Meyer's Loop, and multiple closely neighboring fiber bundles. To date, these unique complexities of the visual pathway have impeded the development of a robust and automated reconstruction method using tractography. To overcome these challenges, we develop a novel, fully automated system to reconstruct the retinofugal visual pathway from high-resolution diffusion imaging data. Using multi-shell, high angular resolution diffusion imaging (HARDI) data, we reconstruct precise fiber orientation distributions (FODs) with high order spherical harmonics (SPHARM) to resolve fiber crossings, which allows the tractography algorithm to successfully navigate the complicated anatomy surrounding the retinofugal pathway. We also develop automated algorithms for the identification of ROIs used for fiber bundle reconstruction. In particular, we develop a novel approach to extract the LGN region of interest (ROI) based on intrinsic shape analysis of a fiber bundle computed from a seed region at the optic chiasm to a target at the primary visual cortex. By combining automatically identified ROIs and FOD-based tractography, we obtain a fully automated system to compute the main components of the retinofugal pathway, including the optic tract and the optic radiation. We apply our method to the multi-shell HARDI data of 215 subjects from the Human Connectome Project (HCP). Through comparisons with post-mortem dissection measurements, we demonstrate the retinotopic organization of the optic radiation including a successful reconstruction of Meyer's loop. Then, using the reconstructed optic radiation bundle from the HCP cohort, we construct a probabilistic atlas and demonstrate its consistency with a post-mortem atlas. Finally, we generate a shape-based representation of the optic radiation for morphometry analysis.
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Kaposvári P, Csete G, Bognár A, Csibri P, Tóth E, Szabó N, Vécsei L, Sáry G, Tamás Kincses Z. Audio–visual integration through the parallel visual pathways. Brain Res 2015; 1624:71-77. [DOI: 10.1016/j.brainres.2015.06.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/20/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
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Lilja Y, Nilsson DT. Strengths and limitations of tractography methods to identify the optic radiation for epilepsy surgery. Quant Imaging Med Surg 2015; 5:288-99. [PMID: 25853086 DOI: 10.3978/j.issn.2223-4292.2015.01.08] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/22/2015] [Indexed: 11/14/2022]
Abstract
Diffusion tensor imaging (DTI) tractography (TG) can visualize Meyer's loop (ML), providing important information for the epilepsy surgery team, both for preoperative counseling and to reduce the frequency of visual field defects after temporal lobe resection (TLR). This review highlights significant steps in the TG process, specifically the processing of raw data including choice of TG algorithm and the interpretation and validation of results. A lack of standardization of TG of the optic radiation makes study comparisons challenging. We discuss results showing differences between studies and uncertainties large enough to be of clinical relevance and present implications of this technique for temporal lobe epilepsy surgery. Recent studies in temporal lobe epilepsy patients, employing TG intraoperatively, show promising results in reduction of visual field defects, with maintained seizure reduction.
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Affiliation(s)
- Ylva Lilja
- 1 Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden ; 2 Department of Neurosurgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Daniel T Nilsson
- 1 Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden ; 2 Department of Neurosurgery, Sahlgrenska University Hospital, Gothenburg, Sweden
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Surgical treatment for mesial temporal lobe epilepsy associated with hippocampal sclerosis. Rev Neurol (Paris) 2015; 171:315-25. [DOI: 10.1016/j.neurol.2015.01.561] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/01/2015] [Accepted: 01/30/2015] [Indexed: 02/07/2023]
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