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- Antonsson, Johan, 1973-
(författare)
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On optical methods for intracerebral measurements during stereotactic and functional neurosurgery : Experimental studies
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radio frequency (RF) lesioning and deep brain stimulation (DBS) are the two prevailing surgical treatments for movement disorders within the field of stereotactic and functional neurosurgery. For RF-lesioning, a small volume of brain tissue is coagulated and knowledge of the lesion size and growth is of great importance for the safety and outcome of the procedure. This thesis deals with adapting the laser Doppler perfusion monitoring (LDPM) technique for measurements in brain tissue during RF-lesioning. The relation between LDPM signal changes and developed lesion size was investigated. LDPM measurements were evaluated both in vitro (albumin protein solution) and in vivo in the porcine brain during RF-lesioning corresponding to a bilateral thalamotomy in man. The investigated signals from the LDPI measurements can be used for following the lesioning time course and to detect if a lesion was created, both in vitro and in the animal model. For the albumin model, both the total backscattered light intensity and the perfusion signal can be used as markers for estimating the final coagulation size, while in the animal model this conclusion was not statistical verified.Independent on surgical method, RF-lesioning or DBS, intracerebral guidance is an important aspect within stereotactic and functional neurosurgery. To increase the accuracy and precision of reaching the correct target, different methods for intracerebral guidance exist, such as microelectrode recording and impedance methods. In this thesis, the possibility of developing an optical intracerebral guidance method has been investigated. Diffuse reflectance spectroscopy served as technology and all measurements were performed stereotactically in both porcine and human brain. Measurements of white and gray matter showed large differences, with higher reflectivity for white brain matter, both in porcine and in human brain. For the human measurements during DBS-implants, large differences between white matter and functional targets were found. Additionally, differences between native and lesioned porcine brain matter were detected. Both studies support the idea of using diffuse reflectance spectroscopy for developing an intracerebral guidance method.
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| 2. |
- Zsigmond, Peter, et al.
(författare)
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Stereptactic microdialysis of the basal ganglia in Parkinson's disease
- 2012
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Ingår i: Journal of Neuroscience Methods. - : Elsevier. - 0165-0270 .- 1872-678X. ; 207:1, s. 17-22
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Tidskriftsartikel (refereegranskat)abstract
- Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an efficacious treatment in patients with advanced Parkinson's disease, yet the mechanisms of STN DBS are poorly understood. The aims of this study were to develop a useful method for studying neurotransmitter alterations during DBS and for the pharmacokinetics of L-dopa in brain tissue. Ten patients with Parkinson's disease participated, whereof two had no previous L-dopa medication. The electrodes and catheters were placed using MRI-guided stereotaxic targeting. Two microdialysis probes were placed, one in the right internal globus pallidus, and one in a brachial vein. The quadripolar deep brain electrodes were placed in the right STN. Microdialysates from brain tissue and blood were collected in 15-min fractions at baseline and during DBS. After stimulation new baseline fractions were taken and finally three fractions during continuous intravenous infusion of L-dopa. Clinical evaluation showed that both DBS and L-dopa infusion gave good relief of rigidity and tremor in all ten patients. During DBS the L-dopa levels in the brain increased in some of the patients but did not persist during the whole stimulation period. The concentration in brain increased substantially during intravenous L-dopa infusion. A number of catecholamines and their metabolites were analysed with high pressure liquid chromatography (HPLC). With our study we could show that this model is suitable for the monitoring of neurotransmitters and for pharmacokinetic studies in human brain, although we found that the sampling time was too short to follow the possible alterations in brain activity caused by DBS.
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