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Hemm, Simone
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Publications (10 of 12) Show all publications
Wårdell, K., Zsigmond, P., Richter, J. & Hemm, S. (2018). Optical Guidance System for Deep Brain Stimulation Surgery: from Experimental Studies to Clinical Use. In: : . Paper presented at Biophotonics Congress: Biomedical Optics Congress, The Diplomat Beach Resort, Hollywood, Florida USA, 3–6 April 2018. Hollywood, Florida, United States, Article ID CTh2B.3.
Open this publication in new window or tab >>Optical Guidance System for Deep Brain Stimulation Surgery: from Experimental Studies to Clinical Use
2018 (English)In: , Hollywood, Florida, United States, 2018, article id CTh2B.3Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Laser Doppler flowmetry (LDF) has been adapted for optical guidance during stereotactic deep brain stimulation (DBS) surgery. It has been used in more than 130 DBS implantations. The necessary steps to go from experimental studies to clinical use in the neurosurgical setting are reviewed.

Place, publisher, year, edition, pages
Hollywood, Florida, United States: , 2018
Series
(Microscopy/Translational/Brain/OTS)
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:liu:diva-147678 (URN)10.1364/TRANSLATIONAL.2018.CTh2B.3 (DOI)978-1-943580-41-5 (ISBN)
Conference
Biophotonics Congress: Biomedical Optics Congress, The Diplomat Beach Resort, Hollywood, Florida USA, 3–6 April 2018
Funder
Swedish Research Council, 621-2013-6078Swedish Foundation for Strategic Research , BD15-0032
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-05-15Bibliographically approved
Alonso, F., Vogel, D., Wårdell, K. & Hemm-Ode, S. (2017). Comparison between intraoperative and chronic and deep brain stimulation. In: : . Paper presented at World Society for Stereotactic and Functional Neurosurgery, 17th Quadrennial meeting, Berlin June 26-29, 2017.
Open this publication in new window or tab >>Comparison between intraoperative and chronic and deep brain stimulation
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

INTRODUCTION

The success of the deep brain stimulation (DBS) therapy relies primarily in the localization of the implanted electrode, implying the need of utmost accuracy in the targeting process. Intraoperative microelectrode recording and stimulation tests are a common procedure before implanting the permanent DBS lead to determine the optimal position with a large therapeutic window where side effects are avoided and the best improvement of the symptoms is achieved. Differences in dimensions and operating modes exist between the exploration and the permanent DBS electrode which might lead to different stimulation fields, even when ideal placement is achieved. The aim of this investigation is to compare the electric field (EF) distribution around the intraoperative and the chronic electrode, assuming that both have exactly the same position.

METHODS

3D models of the intraoperative exploration electrode and the chronically implanted DBS lead 3389 (Medtronic Inc., USA) were developed using COMSOL 5.2 (COMSOL AB, Sweden). Patient-specific MR images were used to determine the conductive medium around the electrode. The exploration electrode and the first DBS contact were set to current and voltage respectively (0.2mA(V) - 3 mA(V) in 0.1 mA(V) steps). The intraoperative model included the grounded guide tube used to introduce the exploration electrode; for the chronic DBS model, the outer boundaries were grounded and the inactive contacts were set to floating potential considering a monopolar configuration. The localization of the exploration and the chronic electrode was set according to the planned trajectory. The EF was visualized and compared in terms of volume and extension using a fixed isocontour of 0.2 V/mm.

RESULTS

The EF distribution simulated for the exploration electrode showed the influence of the parallel trajectory and the grounded guide tube. For an amplitude of e.g. 2 mA/2 V, the EF extension of the intraoperative was 0.6 mm larger than the chronic electrode at the target level; the corresponding difference in volume was 76.1 mm3.

CONCLUSION

Differences in the EF shape between the exploration and the chronic DBS electrode have been observed using patient-specific models. The larger EF extension obtained for the exploration electrode responds to its higher impedance and the use of current controlled stimulation. The presence of EF around the guide tube and the influence of the parallel trajectory require further experimental and clinical evaluation.

National Category
Medical Engineering
Identifiers
urn:nbn:se:liu:diva-139880 (URN)
Conference
World Society for Stereotactic and Functional Neurosurgery, 17th Quadrennial meeting, Berlin June 26-29, 2017
Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2017-08-21
Shah, A., Alonso, F., Lemarie, J.-J., Pison, D., Coste, J., Wårdell, K., . . . Hemm-Ode, S. (2017). Learning more about the optimal anatomical position for deep brain stimulation in essential tremor patients: 3D visualisation of intraoperative stimulation test results. In: : . Paper presented at World Society for Stereotactic and Functional Neurosurgery, 17th Quadrennial meeting, Berlin June 26-29, 2017.
Open this publication in new window or tab >>Learning more about the optimal anatomical position for deep brain stimulation in essential tremor patients: 3D visualisation of intraoperative stimulation test results
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2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

INTRODUCTION

The outcome of deep brain stimulation (DBS) depends heavily on the position of the implanted lead. After a preoperative anatomical planning, most groups collect numerous intraoperative data such as therapeutic effects induced by stimulation tests. To choose the final implant position, physicians “mentally” visualise all available data. The aim of the present work was to develop a method visualising intraoperative stimulation test results, patient’s images, electric field (EF) simulations for the patient-specific stimulation conditions and the corresponding therapeutic effects quantitatively evaluated by accelerometry. The application to five essential tremor (ET) patients should give a first idea about the optimal target position. 

METHODS

In Clermont-Ferrand University Hospital the anatomic target structure and the neighbouring structures were manually outlined, a target and a trajectory defined and two parallel trajectories per hemisphere intraoperatively evaluated. Stimulation tests were performed at 7 to 8 positions per trajectory and several stimulation current amplitudes. The therapeutic effect was evaluated using a previously published method based on accelerometry. Finite element models and simulations were performed for up to three stimulation amplitudes per position and EF isosurfaces (0.2V/mm) were extracted. For the 3D visualization of the numerous overlapping isosurfaces, we generated “improvement maps” by assigning to each voxel within the isosurfaces the highest tremor improvement. Those maps were visualized together with anatomical images, delineated structures and trajectories (Paraview, Kitware Inc). The method was applied to 5 ET patients implanted in the ventro-intermediate nucleus of the thalamus (VIM). Results were analysed by the neurosurgeon regarding the optimal implant position.  

RESULTS

The clinical teams were able to identify the optimal implant position for all patients with more ease and in less time compared to the routine discussion using pen and paper. Additionally, for 7 of the 9 improvement maps, the highest improvement region was found to be in the posterior subthalamic area, inferior and posterior to the VIM.

CONCLUSION

Improvement maps assist the clinicians in determining the optimal implant location of the chronic DBS lead. Results support findings of other studies that the fibre tracts in the posterior subthalamic area like prelemniscal radiations may be responsible for alleviating tremor in ET patients.

National Category
Medical Engineering
Identifiers
urn:nbn:se:liu:diva-139878 (URN)
Conference
World Society for Stereotactic and Functional Neurosurgery, 17th Quadrennial meeting, Berlin June 26-29, 2017
Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2017-08-21
Wårdell, K., Hemm-Ode, S., Rejmstad, P. & Zsigmond, P. (2016). High-Resolution Laser Doppler Measurements of Microcirculation in the Deep Brain Structures: A Method for Potential Vessel Tracking.. Stereotactic and Functional Neurosurgery, 94(1), 1-9
Open this publication in new window or tab >>High-Resolution Laser Doppler Measurements of Microcirculation in the Deep Brain Structures: A Method for Potential Vessel Tracking.
2016 (English)In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 94, no 1, p. 1-9Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Laser Doppler flowmetry (LDF) can be used to measure cerebral microcirculation in relation to stereotactic deep brain stimulation (DBS) implantations.

OBJECTIVE: To investigate the microcirculation and total light intensity (TLI) corresponding to tissue grayness in DBS target regions with high-resolution LDF recordings, and to define a resolution which enables detection of small vessels.

METHODS: Stereotactic LDF measurements were made prior to DBS implantation with 0.5-mm steps in the vicinity to 4 deep brain targets (STN, GPi, Vim, Zi) along 20 trajectories. The Mann-Whitney U test was used to compare the microcirculation and TLI between targets, and the measurement resolution (0.5 vs. 1 mm). The numbers of high blood flow spots along the trajectories were calculated.

RESULTS: There was a significant difference (p < 0.05) in microcirculation between the targets. High blood flow spots were present at 15 out of 510 positions, 7 along Vim and GPi trajectories, respectively. There was no statistical difference between resolutions even though both local blood flow and TLI peaks could appear at 0.5-mm steps.

CONCLUSIONS: LDF can be used for online tracking of critical regions presenting blood flow and TLI peaks, possibly relating to vessel structures and thin laminas along stereotactic trajectories.

Place, publisher, year, edition, pages
S. Karger, 2016
Keywords
Deep brain stimulation · Laser Doppler flowmetry ·Stereotactic neurosurgery · Microcirculation · Navigation
National Category
Biomedical Laboratory Science/Technology Neurology
Identifiers
urn:nbn:se:liu:diva-124691 (URN)10.1159/000442894 (DOI)000373869900001 ()26795207 (PubMedID)
Note

Funding agencies:  Swedish Research Council [621-2013-6078]; Parkinson Foundation at Linkoping University; Swiss National Science Foundation [205321-135285]

Available from: 2016-02-10 Created: 2016-02-10 Last updated: 2017-11-30Bibliographically approved
Alonso, F., Hemm-Ode, S. & Wårdell, K. (2015). Influence on Deep Brain Stimulation from Lead Design, Operating Mode and Tissue Impedance Changes – A Simulation Study. Brain Disorders and Therapy, 4(3), Article ID 1000169.
Open this publication in new window or tab >>Influence on Deep Brain Stimulation from Lead Design, Operating Mode and Tissue Impedance Changes – A Simulation Study
2015 (English)In: Brain Disorders and Therapy, ISSN 2168-975X, Vol. 4, no 3, article id 1000169Article in journal (Refereed) Published
Abstract [en]

Background: Deep brain stimulation (DBS) systems in current mode and new lead designs are recently available. To switch between DBS-systems remains complicated as clinicians may lose their reference for programming. Simulations can help increase the understanding.

Objective: To quantitatively investigate the electric field (EF) around two lead designs simulated to operate in voltage and current mode under two time points following implantation.

Methods: The finite element method was used to model Lead 3389 (Medtronic) and 6148 (St Jude) with homogenous surrounding grey matter and a peri-electrode space (PES) of 250 μm. The PES-impedance mimicked the acute (extracellular fluid) and chronic (fibrous tissue) time-point. Simulations at different amplitudes of voltage and current (n=236) were performed using two different contacts. Equivalent current amplitudes were extracted by matching the shape and maximum EF of the 0.2 V/mm isolevel.

Results: The maximum EF extension at 0.2 V/mm varied between 2-5 mm with a small difference between the leads. In voltage mode EF increased about 1 mm at acute compared to the chronic PES. Current mode presented the opposite relationship. Equivalent EFs for lead 3389 at 3 V were found for 7 mA (acute) and 2.2 mA (chronic).

Conclusions: Simulations showed a major impact on the electric field extension between postoperative time points. This may explain the clinical decisions to reprogram the amplitude weeks after implantation. Neither the EF extension nor intensity is considerably influenced by the lead design.

Place, publisher, year, edition, pages
Los Angeles, CA, USA: Omics Publishing Group, 2015
Keywords
deep brain stimulation (DBS), voltage and current stimulation, finite element method
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-120680 (URN)10.4172/2168-975X.1000169 (DOI)
Funder
Swedish Research Council, 621-2013-6078
Available from: 2015-08-21 Created: 2015-08-20 Last updated: 2018-09-10Bibliographically approved
Wårdell, K., Haj-Hosseini, N. & Hemm-Ode, S. (2014). Comparison between Optical and MRI Trajectories in Stereotactic Neurosurgery. In: Laura M. Roa Romero (Ed.), XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013 : MEDICON 2013, 25 - 28 September 2013, Seville, Spain: . Paper presented at XIII Mediterranean Conference on Medical and Biological Engineering and Computing (pp. 49-51).
Open this publication in new window or tab >>Comparison between Optical and MRI Trajectories in Stereotactic Neurosurgery
2014 (English)In: XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013 : MEDICON 2013, 25 - 28 September 2013, Seville, Spain / [ed] Laura M. Roa Romero, 2014, p. 49-51Conference paper, Published paper (Refereed)
Abstract [en]

Deep brain stimulation (DBS) is an effective treatment for movement disorders e.g. Parkinson's disease. Thin electrodes are implanted into the deep brain structures by means of stereotactic technique and electrical stimulations are delivered to the brain tissue. Accuracy and safety during the implantation is important for optimal stimulation effect and minimization of bleedings. In addition to microelectrode recording and impedance measurements, intraoperative optical measurements using laser Doppler perfusion monitoring (LDPM) have previously been suggested as guidance tool during stereotactic DBS implantations. In this study we compare optical trajectories, recorded with LDPM ranging from cortex towards the subthalamic nucleus (STN), to the corresponding magnetic resonance imaging (MRI) trajectories. Inversed gray scales from the T2-weighted MRI were used for comparison with the total light intensity (TLI) representing tissue grayness. Both curves followed a general tendency with a deep dip in the vicinity to the left ventricle. MRI trajectories might help in predicting the optical trajectory but further studies including more data and fine tuning of the comparative methodology are required

Series
IFMBE Proceedings, ISSN 1680-0737 ; vol 41
Keywords
Deep brain stimulation; Laser doppler perfusion monitoring; Magnetic resonance imaging; Stereotaxy
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:liu:diva-98652 (URN)10.1007/978-3-319-00846-2_12 (DOI)2-s2.0-84891330524 (Scopus ID)9783319008455 (ISBN)
Conference
XIII Mediterranean Conference on Medical and Biological Engineering and Computing
Available from: 2013-10-10 Created: 2013-10-10 Last updated: 2017-02-03Bibliographically approved
Wårdell, K., Rejmstad, P., Hemm-Ode, S., Richter, J. & Zsigmond, P. (2014). Microvascular Blood Flow in the Deep Brain Structures - Laser Doppler Measurements during DBS-implantations. In: Movement Disorders 2014, Volym 29, Suppl 1 :1271: . Paper presented at 18th International Congress of Parkinson's Disease and Movement Disorders, June 8-12 2014, Stockholm, Sweden.
Open this publication in new window or tab >>Microvascular Blood Flow in the Deep Brain Structures - Laser Doppler Measurements during DBS-implantations
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2014 (English)In: Movement Disorders 2014, Volym 29, Suppl 1 :1271, 2014Conference paper, Poster (with or without abstract) (Other academic)
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:liu:diva-107592 (URN)
Conference
18th International Congress of Parkinson's Disease and Movement Disorders, June 8-12 2014, Stockholm, Sweden
Available from: 2014-06-17 Created: 2014-06-17 Last updated: 2017-02-03Bibliographically approved
Wårdell, K. & Hemm-Ode, S. (2014). Optical and microvascular measurements for guidance during DBS implantation. In: : . Paper presented at 1st IMPACT Workshop and 7th NeuroTech Workshop, May 15-16, 2014, Linköping, Sweden.
Open this publication in new window or tab >>Optical and microvascular measurements for guidance during DBS implantation
2014 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:liu:diva-107607 (URN)
Conference
1st IMPACT Workshop and 7th NeuroTech Workshop, May 15-16, 2014, Linköping, Sweden
Available from: 2014-06-17 Created: 2014-06-17 Last updated: 2017-02-03Bibliographically approved
Hemm-Ode, S. (2014). Patient-specific electric field simulations and acceleration measurements for intraoperative test-stimulations. In: : . Paper presented at 1st IMPACT Workshop and 7th NeuroTech Workshop, May 15-16, 2014, Linköping, Sweden.
Open this publication in new window or tab >>Patient-specific electric field simulations and acceleration measurements for intraoperative test-stimulations
2014 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Medical Engineering
Identifiers
urn:nbn:se:liu:diva-107611 (URN)
Conference
1st IMPACT Workshop and 7th NeuroTech Workshop, May 15-16, 2014, Linköping, Sweden
Available from: 2014-06-17 Created: 2014-06-17 Last updated: 2017-02-03Bibliographically approved
Hemm-Ode, S. & Wårdell, K. (2012). Correlation between laser Doppler measurements and anatomy during deep brain stimulation surgery. Paper presented at BMT 2012,46th DGBMT Annual Conference, September 16-19, 2012, Jena, Germany. Biomedical Engineering, 57
Open this publication in new window or tab >>Correlation between laser Doppler measurements and anatomy during deep brain stimulation surgery
2012 (English)In: Biomedical Engineering, ISSN 0006-3398, E-ISSN 1573-8256, Vol. 57Article in journal (Refereed) Published
Abstract [en]

Introduction

In Deep Brain Stimulation (DBS) the save, accurate and precise electrode implantation is essential. We have previously presented an optical technique for intra-operative measurements during DBS implantation. The aim of the present study was to establish the link between anatomy and total light intensity (TLI, the greyness of the tissue) and microvascular perfusion recordings.

Methods

Twelve patients (6 subthalamic nucleus STN, 6 ventral intermediate nucleus Vim) referred for unilateral or bilateral DBS-implantation for the treatment of essential tremor or Parkinson’s disease were included in the study. Stereotactic CT imaging was used for planning of the trajectories and targets (n=22). Measurement of the TLI and the microvascular perfusion were performed in mm-steps along the trajectory. TLI and perfusion data were post-processed to “optical trajectories” ranging from the cortex towards the target. These were compared with anatomy along the final trajectories by the use of a brain atlas and Surgiplan.

Results

Post-processing of the TLI signal showed a clear relationship with anatomy. Characteristic median curves were determined. The curve normally started with low values for STN and Vim patients when in cortex. When the probe entered white matter the TLI increased and stayed at this level until it passed in the vicinity to putamen, caudate nucleus or ventricle. A statistical significant difference (p<0.05) could be shown between white matter and putamen and between white matter and the target area. Concerning microvascular perfusion, high values were often seen in the cortex and low ones in white matter (significant statistical difference: p<0.05). In one case a small bleeding was suspected during surgery with the optical technique. This was confirmed with post-operative CT.

Conclusion

In summary the optical technique show promising results and typical trajectories were defined towards the STN and Vim, but further evaluation is necessary in order to refine the “optical bar codes” towards specific DBS-targets.

Place, publisher, year, edition, pages
Berlin: Walter de Gruyter, 2012
National Category
Medical Engineering
Identifiers
urn:nbn:se:liu:diva-81377 (URN)10.1515/bmt-2012-4327 (DOI)000312675100267 ()
Conference
BMT 2012,46th DGBMT Annual Conference, September 16-19, 2012, Jena, Germany
Available from: 2012-09-12 Created: 2012-09-12 Last updated: 2017-12-07Bibliographically approved
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