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Arvaniti CK, Brotis AG, Paschalis T, Kapsalaki EZ, Fountas KN. Localization of Vestibular Cortex Using Electrical Cortical Stimulation: A Systematic Literature Review. Brain Sci 2024; 14:75. [PMID: 38248290 PMCID: PMC10813901 DOI: 10.3390/brainsci14010075] [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: 12/20/2023] [Revised: 01/07/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
The vestibular system plays a fundamental role in body orientation, posture control, and spatial and body motion perception, as well as in gaze and eye movements. We aimed to review the current knowledge regarding the location of the cortical and subcortical areas, implicated in the processing of vestibular stimuli. The search was performed in PubMed and Scopus. We focused on studies reporting on vestibular manifestations after electrical cortical stimulation. A total of 16 studies were finally included. Two main types of vestibular responses were elicited, including vertigo and perception of body movement. The latter could be either rotatory or translational. Electrical stimulation of the temporal structures elicited mainly vertigo, while stimulation of the parietal lobe was associated with perceptions of body movement. Stimulation of the occipital lobe produced vertigo with visual manifestations. There was evidence that the vestibular responses became more robust with increasing current intensity. Low-frequency stimulation proved to be more effective than high-frequency in eliciting vestibular responses. Numerous non-vestibular responses were recorded after stimulation of the vestibular cortex, including somatosensory, viscero-sensory, and emotional manifestations. Newer imaging modalities such as functional MRI (fMRI), Positron Emission Tomography (PET), SPECT, and near infra-red spectroscopy (NIRS) can provide useful information regarding localization of the vestibular cortex.
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Affiliation(s)
- Christina K. Arvaniti
- Department of Neurosurgery, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (C.K.A.); (A.G.B.)
| | - Alexandros G. Brotis
- Department of Neurosurgery, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (C.K.A.); (A.G.B.)
| | - Thanasis Paschalis
- Department of Neuro-Oncology, Cambridge University Hospital, Cambridge CB4 1GN, UK;
| | - Eftychia Z. Kapsalaki
- Department of Diagnostic Radiology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100 Larisa, Greece;
- Advanced Diagnostic Institute Euromedica-Encephalos, 15233 Athens, Greece
| | - Kostas N. Fountas
- Department of Neurosurgery, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (C.K.A.); (A.G.B.)
- Faculty of Medicine, University of Thessaly, Biopolis, 41110 Larissa, Greece
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Kwon KJ, Byun JY. Asymmetry of Gray- and White-Matter Volume and Metabolites in the Central-Vestibular System in Healthy Individuals. J Clin Med 2023; 12:jcm12041272. [PMID: 36835808 PMCID: PMC9967821 DOI: 10.3390/jcm12041272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/25/2023] [Accepted: 02/04/2023] [Indexed: 02/09/2023] Open
Abstract
This study was designed to determine whether there was an asymmetry of structure and neurochemical activity of the interhemispheric vestibular-cortical system between healthy individuals and patients with vestibular failure. Previous studies have identified differences in gray-matter-volume (GMV) and white-matter-volume (WMV) asymmetry in the central-vestibular system and in concentrations of brain metabolites in the parietal lobe 2 (PO2) between patients with vestibulopathy and healthy controls. However, a comparison of the left and right sides in the healthy controls has not been made conclusively. This study included 23 healthy right-handed volunteers, and was carried out between March 2016 and March 2020. A three-dimensional T1-weighted image was used to calculate the GMV and WMV of the central-vestibular network on both sides, and proton magnetic resonance spectroscopy (H1MRS) was employed to analyze the brain metabolites in the PO2 area. The relative ratios of N-acetylaspartate (NAA)/tCr, tNAA/tCr, glycerophosphocholine (GPC)/tCr, Glx/tCr, and myo-inositol/tCr were quantified from the proton-MRS data. GMV and WMV differed significantly between the right and left vestibular-cortical regions. The GMVs of the right PO2, caudate, insula, and precuneus were significantly higher than those of the same locations on the left side; however, in the Rolandic operculum, the GMV on the left was significantly higher than on the right. In the PO2, Rolandic operculum, thalamus, and insula, the WMV on the left side was higher than on the right side of the corresponding location. However, the right caudate and precuneus WMV were higher than the left at the same location. In the H1MRS study, the Glx/tCr and GPC/tCr ratios on the left side were significantly higher than on the right. In comparison, the NAA/tCr and tNAA/tCr ratios showed contrasting results. The NAA/tCr ratio (r = -0.478, p = 0.021), tNAA/tCr ratio (r = -0.537, p = 0.008), and Glx/tCr ratio (r = -0.514, p = 0.012) on the right side showed a significant negative correlation with the participants' age. There was no relationship between GMV and metabolites on either side. Brain structure and concentrations of brain metabolites related to the vestibular system may differ between the two hemispheres in healthy individuals. Therefore, the asymmetry of the central-vestibular system should be considered when performing imaging.
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Nakul E, Bartolomei F, Lopez C. Vestibular-Evoked Cerebral Potentials. Front Neurol 2021; 12:674100. [PMID: 34621231 PMCID: PMC8490637 DOI: 10.3389/fneur.2021.674100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/20/2021] [Indexed: 11/30/2022] Open
Abstract
The human vestibular cortex has mostly been approached using functional magnetic resonance imaging and positron emission tomography combined with artificial stimulation of the vestibular receptors or nerve. Few studies have used electroencephalography and benefited from its high temporal resolution to describe the spatiotemporal dynamics of vestibular information processing from the first milliseconds following vestibular stimulation. Evoked potentials (EPs) are largely used to describe neural processing of other sensory signals, but they remain poorly developed and standardized in vestibular neuroscience and neuro-otology. Yet, vestibular EPs of brainstem, cerebellar, and cortical origin have been reported as early as the 1960s. This review article summarizes and compares results from studies that have used a large range of vestibular stimulation, including natural vestibular stimulation on rotating chairs and motion platforms, as well as artificial vestibular stimulation (e.g., sounds, impulsive acceleration stimulation, galvanic stimulation). These studies identified vestibular EPs with short latency (<20 ms), middle latency (from 20 to 50 ms), and late latency (>50 ms). Analysis of the generators (source analysis) of these responses offers new insights into the neuroimaging of the vestibular system. Generators were consistently found in the parieto-insular and temporo-parietal junction-the core of the vestibular cortex-as well as in the prefrontal and frontal areas, superior parietal, and temporal areas. We discuss the relevance of vestibular EPs for basic research and clinical neuroscience and highlight their limitations.
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Affiliation(s)
- Estelle Nakul
- Centre National de la Recherche Scientifique (CNRS), Laboratoire de Neurosciences Cognitives (LNC), FR3C, Aix Marseille Univ, Marseille, France
| | - Fabrice Bartolomei
- Institut de Neurosciences des Systèmes, Inserm, Aix Marseille Univ, Marseille, France
- Service de Neurophysiologie Clinique, Hôpital Timone, Aix Marseille Univ, Marseille, France
| | - Christophe Lopez
- Centre National de la Recherche Scientifique (CNRS), Laboratoire de Neurosciences Cognitives (LNC), FR3C, Aix Marseille Univ, Marseille, France
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Devantier L, Hansen AK, Mølby-Henriksen JJ, Pedersen M, Borghammer P, Ovesen T, Magnusson M. Cortical Activity During an Attack of Ménière's Disease-A Case Report. Front Neurol 2021; 12:669390. [PMID: 34367048 PMCID: PMC8339298 DOI: 10.3389/fneur.2021.669390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Ménière's disease (MD) is a chronic peripheral vestibular disorder with recurrent episodes of vertigo accompanied by fluctuating hearing loss, tinnitus and aural fullness in the affected ear. There are several unanswered fundamental questions regarding MD, one of these being cortical activity during a MD attack. However, it is not possible to plan an investigation in an episodic disease as MD. Objective: To visualize cortical activity during an attack of MD. Method: 18F-FDG PET scans were used to visualize cortical activity in a 62 years old male suffering from definite MD. Two 18F-FDG PET scans were performed. One to show activity during the attack and one to show normal baseline brain activity 7 days after the attack. Results: A number of low-magnitude fluctuations in the 18F-FDG FDG uptake were found in 18F-FDG PET examination following the MD attack compared to the patient's own baseline 18F-FDG FDG scan. Across both hemispheres no significant changes were seen. However, reduced activity was observed in most of the orbitofrontal, frontal cortices as well as Heschl's gyrus and insula. Conclusion: This is the first neuroimaging showing alteration of brain activity during an attack in a patient with MD. No strong focal alterations was seen. It is noteworthy that the decreased activity observed was in the insula and Heschl's gyrus that seems to be core areas for processing information from the labyrinth. It is also of interest that decreased activity rather than hyperactivity was observed.
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Affiliation(s)
- Louise Devantier
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Allan K Hansen
- Department of Nuclear Medicine, Positron Emission Tomography (PET) Centre, Aarhus University Hospital, Aarhus, Denmark
| | | | - Michael Pedersen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Comparative Medicine Lab, Aarhus University, Aarhus, Denmark
| | - Per Borghammer
- Department of Nuclear Medicine, Positron Emission Tomography (PET) Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Therese Ovesen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Måns Magnusson
- Department of Oto-Rhino-Laryngology, Lund University Hospital, Lund, Sweden
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Indovina I, Bosco G, Riccelli R, Maffei V, Lacquaniti F, Passamonti L, Toschi N. Structural connectome and connectivity lateralization of the multimodal vestibular cortical network. Neuroimage 2020; 222:117247. [PMID: 32798675 PMCID: PMC7779422 DOI: 10.1016/j.neuroimage.2020.117247] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/28/2020] [Accepted: 08/05/2020] [Indexed: 01/05/2023] Open
Abstract
Unlike other sensory systems, the structural connectivity patterns of the human vestibular cortex remain a matter of debate. Based on their functional properties and hypothesized centrality within the vestibular network, the ‘core’ cortical regions of this network are thought to be areas in the posterior peri-sylvian cortex, in particular the retro-insula (previously named the posterior insular cortex-PIC), and the subregion OP2 of the parietal operculum. To study the vestibular network, structural connectivity matrices from n=974 healthy individuals drawn from the public Human Connectome Project (HCP) repository were estimated using multi-shell diffusion-weighted data followed by probabilistic tractography and spherical-deconvolution informed filtering of tractograms in combination with subject-specific grey-matter parcellations. Weighted graph-theoretical measures, modularity, and ‘hubness’ of the multimodal vestibular network were then estimated, and a structural lateralization index was defined in order to assess the difference in fiber density of homonym regions in the right and left hemisphere. Differences in connectivity patterns between OP2 and PIC were also estimated. We found that the bilateral intraparietal sulcus, PIC, and to a lesser degree OP2, are key ‘hub’ regions within the multimodal vestibular network. PIC and OP2 structural connectivity patterns were lateralized to the left hemisphere, while structural connectivity patterns of the posterior peri-sylvian supramarginal and superior temporal gyri were lateralized to the right hemisphere. These lateralization patterns were independent of handedness. We also found that the structural connectivity pattern of PIC is consistent with a key role of PIC in visuo-vestibular processing and that the structural connectivity pattern of OP2 is consistent with integration of mainly vestibular somato-sensory and motor information. These results suggest an analogy between PIC and the simian visual posterior sylvian (VPS) area and OP2 and the simian parieto-insular vestibular cortex (PIVC). Overall, these findings may provide novel insights to the current models of vestibular function, as well as to the understanding of the complexity and lateralized signs of vestibular syndromes.
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Affiliation(s)
- Iole Indovina
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, via Ardeatina 354, 00179 Rome, Italy.
| | - Gianfranco Bosco
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, via Ardeatina 354, 00179 Rome, Italy; Department of Systems Medicine and Centre of Space BioMedicine, University of Rome Tor Vergata, 00173 Rome, Italy
| | - Roberta Riccelli
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, via Ardeatina 354, 00179 Rome, Italy
| | - Vincenzo Maffei
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, via Ardeatina 354, 00179 Rome, Italy
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, via Ardeatina 354, 00179 Rome, Italy; Department of Systems Medicine and Centre of Space BioMedicine, University of Rome Tor Vergata, 00173 Rome, Italy
| | - Luca Passamonti
- Department of Clinical Neurosciences, University of Cambridge, UK; Institute of Bioimaging & Molecular Physiology, National Research Council, Milano, Italy; IRCCS San Camillo Hospital, Venice, Italy.
| | - Nicola Toschi
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", 00133 Rome, Italy; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, USA
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Helmchen C, Machner B, Rother M, Spliethoff P, Göttlich M, Sprenger A. Effects of galvanic vestibular stimulation on resting state brain activity in patients with bilateral vestibulopathy. Hum Brain Mapp 2020; 41:2527-2547. [PMID: 32103579 PMCID: PMC7267973 DOI: 10.1002/hbm.24963] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 01/04/2023] Open
Abstract
We examined the effect of galvanic vestibular stimulation (GVS) on resting state brain activity using fMRI (rs‐fMRI) in patients with bilateral vestibulopathy. Based on our previous findings, we hypothesized that GVS, which excites the vestibular nerve fibers, (a) increases functional connectivity in temporoparietal regions processing vestibular signals, and (b) alleviates abnormal visual–vestibular interaction. Rs‐fMRI of 26 patients and 26 age‐matched healthy control subjects was compared before and after GVS. The stimulation elicited a motion percept in all participants. Using different analyses (degree centrality, DC; fractional amplitude of low frequency fluctuations [fALFF] and seed‐based functional connectivity, FC), group comparisons revealed smaller rs‐fMRI in the right Rolandic operculum of patients. After GVS, rs‐fMRI increased in the right Rolandic operculum in both groups and in the patients' cerebellar Crus 1 which was related to vestibular hypofunction. GVS elicited a fALFF increase in the visual cortex of patients that was inversely correlated with the patients' rating of perceived dizziness. After GVS, FC between parietoinsular cortex and higher visual areas increased in healthy controls but not in patients. In conclusion, short‐term GVS is able to modulate rs‐fMRI in healthy controls and BV patients. GVS elicits an increase of the reduced rs‐fMRI in the patients' right Rolandic operculum, which may be an important contribution to restore the disturbed visual–vestibular interaction. The GVS‐induced changes in the cerebellum and the visual cortex were associated with lower dizziness‐related handicaps in patients, possibly reflecting beneficial neural plasticity that might subserve visual–vestibular compensation of deficient self‐motion perception.
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Affiliation(s)
- Christoph Helmchen
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Björn Machner
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Matthias Rother
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Peer Spliethoff
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Martin Göttlich
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Andreas Sprenger
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany.,Institute of Psychology II, University of Lübeck, Lübeck, Germany
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Devantier L, Hansen AK, Mølby-Henriksen JJ, Christensen CB, Lildal T, Pedersen M, Magnusson M, Borghammer P, Ovesen T. PET Visualized Stimulation of the Vestibular Organ in Menière's Disease. Front Neurol 2020; 11:11. [PMID: 32047473 PMCID: PMC6997538 DOI: 10.3389/fneur.2020.00011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/07/2020] [Indexed: 01/05/2023] Open
Abstract
Introduction: The cortical metabolic activity in patients with Menière's disease has not been investigated. The aim of this study was to investigate the 18F-FDG cerebral uptake in Menière's patients compared to healthy controls. Method: Eight patients with right-sided Menière's disease and fourteen healthy controls underwent a video head impulse test (vHIT), test of utricular function with ocular vestibular evoked myogenic potentials (oVEMP) and three 18F-FDG-based PET examinations of the brain. Participants were seated in a self-propelled chair, injected with 18F-FDG and then exposed to 35 min of chair motion stimulation, followed by a PET scan. Two types of natural vestibular stimuli were applied, predominantly toward the right horizontal semicircular canal (angular acceleration) and right utriculus (linear acceleration). For baseline scans, participants were injected with 18F-FDG while seated without movement. Results: Analyses of baseline scans revealed decreased 18F-FDG-uptake in the medial part of Heschl's gyrus in the left hemisphere in patients with Menière's disease compared to healthy controls. During angular vestibular stimulation there was also a significantly decreased 18F-FDG uptake in the intersection between the medial part of Heschl's gyrus and the parietal operculum in the left hemisphere and bilaterally in the posterior part of insula. During linear stimulation, Menière's patients showed decreased 18F-FDG uptake in the medial part of Heschl's gyrus in the right hemisphere and also bilaterally in the posterior insula. In addition, decreased 18F-FDG uptake was seen in the thalamus during vestibular stimulation. Conclusion: Heschl's gyrus, the posterior part of insula, and thalamus have previously been shown to be core areas for processing vestibular inputs. Patients with Menière's disease solely differed from the healthy controls with lower cortical activity in these areas at baseline and during natural vestibular stimulation.
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Affiliation(s)
- Louise Devantier
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holsterbo, Denmark
| | - Allan K Hansen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Tina Lildal
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holsterbo, Denmark
| | - Michael Pedersen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Comparative Medicine Lab, Aarhus University, Aarhus, Denmark
| | - Måns Magnusson
- Department of Oto-Rhino-Laryngology, Lund University Hospital, Lund, Sweden
| | - Per Borghammer
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Therese Ovesen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holsterbo, Denmark
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Devantier L, Hansen AK, Mølby-Henriksen JJ, Christensen CB, Pedersen M, Hansen KV, Magnusson M, Ovesen T, Borghammer P. Positron emission tomography visualized stimulation of the vestibular organ is localized in Heschl's gyrus. Hum Brain Mapp 2019; 41:185-193. [PMID: 31520516 PMCID: PMC7268041 DOI: 10.1002/hbm.24798] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 08/12/2019] [Accepted: 09/04/2019] [Indexed: 11/10/2022] Open
Abstract
The existence of a human primary vestibular cortex is still debated. Current knowledge mainly derives from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) acquisitions during artificial vestibular stimulation. This may be problematic as artificial vestibular stimulation entails coactivation of other sensory receptors. The use of fMRI is challenging as the strong magnetic field and loud noise during MRI may both stimulate the vestibular organ. This study aimed to characterize the cortical activity during natural stimulation of the human vestibular organ. Two fluorodeoxyglucose (FDG)-PET scans were obtained after natural vestibular stimulation in a self-propelled chair. Two types of stimuli were applied: (a) rotation (horizontal semicircular canal) and (b) linear sideways movement (utriculus). A comparable baseline FDG-PET scan was obtained after sitting motion-less in the chair. In both stimulation paradigms, significantly increased FDG uptake was measured bilaterally in the medial part of Heschl's gyrus, with some overlap into the posterior insula. This is the first neuroimaging study to visualize cortical processing of natural vestibular stimuli. FDG uptake was demonstrated in the medial-most part of Heschl's gyrus, normally associated with the primary auditory cortex. This anatomical localization seems plausible, considering that the labyrinth contains both the vestibular organ and the cochlea.
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Affiliation(s)
- Louise Devantier
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Allan K Hansen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | | | | | | | - Kim V Hansen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Måns Magnusson
- Department of Oto-Rhino-Laryngology, Lund University Hospital, Lund, Sweden
| | - Therese Ovesen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Per Borghammer
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
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