Biomedical subjects

W L Nowinski

Publications and source records attributed to W L Nowinski.

10 recordsLinked to original sources

PubMed2000

Insights into the three-dimensional structure of the oculomotor nuclear complex and fascicles.

The authors report the case of a patient with an ischemic lesion in the left midbrain. The patient presented with paresis of left inferior rectus, pupil, right superior rectus, convergence and transiently, of the left medial rectus. A lesion in the left dorsal midbrain close to the oculomotor nuclear complex, selectively involving the fascicles innervating the above muscles, is proposed. Fine magnetic resonance sections showed a consistent lesion in the left paramedian dorsal midbrain. A detailed, three-dimensional, schematic computer model of the oculomotor nucleus and fascicles was constructed. Using this model, the authors topographically validate the putative site of the lesion. The medial rectus subnucleus is divided into three subgroups, A, B, and C. Subgroup C is thought to be the site of the majority of neurons controlling convergence. In the above model, the putative lesion is closer to subgroup A than to C; this suggests that subgroup A, rather than subgroup C, may have a higher concentration of neurons involved in convergence.

Brain Ischemia↗

PubMed2000

Computer-aided stereotactic functional neurosurgery enhanced by the use of the multiple brain atlas database.

This paper introduces a computer-aided atlas-based functional neurosurgery methodology and describes NeuroPlanner, a software system which supports it. NeuroPlanner provides four groups of functions: 1) data-related for data reading, interpolation, reformatting, and image processing; 2) atlas-related for multiple atlases reading, atlas-to-data global and local registrations, two-way anatomical indexing, and multiple labeling in two and three dimensions; 3) atlas-data exploration-related for three-dimensional (3-D) display and real-time manipulation of cerebral structures, continuous navigation, two-dimensional (2-D), triplanar, 3-D presentations, and 2-D interaction in four views; and 4) neurosurgery-related for targeting, trajectory planning, mensuration, simulating the insertion of microelectrode, and simulating therapeutic lesioning. All operations, excluding atlas and data reading, are real time. The combined anatomical index of the multiple brain atlas database containing complementary 2-D and 3-D atlases has about 1000 structures per hemisphere, and over 400 sulcal patterns. Neurosurgical planning with mutually preregistered multiple brain atlases in all three orthogonal orientations is novel. The approach is validated with 24 intraoperative and postoperative datasets for thalamotomies, thalamic stimulations, pallidotomies, and pallidal stimulations. Its potential benefits include increased accuracy of target definition, reduced time of the surgical procedure by decreasing the number of tracts, facilitated planning of more sophisticated trajectories, lowered cost by reducing the number of microelectrodes used, reduced surgical complications, and the extra degree of confidence given to the neurosurgeon.

Brain Mapping↗

PubMed2000

Planning and simulation of neurosurgery in a virtual reality environment.

OBJECTIVE: To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations. METHODS: A neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization and Navigation) was developed for the Dextroscope, a virtual reality environment in which the operator reaches with both hands behind a mirror into a computer-generated stereoscopic three-dimensional (3-D) object and moves and manipulates the object in real time with natural 3-D hand movements. Patient-specific data sets from multiple imaging techniques (magnetic resonance imaging, magnetic resonance angiography, magnetic resonance venography, and computed tomography) were coregistered, fused, and displayed as a stereoscopic 3-D object. A suite of 3-D tools accessible inside the VIVIAN workspace enabled users to coregister data, perform segmentation, obtain measurements, and simulate intraoperative viewpoints and the removal of bone and soft tissue. RESULTS: VIVIAN was used to plan neurosurgical procedures primarily in difficult-to-access areas, such as the cranial base and the deep brain. The intraoperative and virtual reality 3-D scenarios correlated well. The VIVIAN system substantially contributed to surgical planning by 1) providing a quick and better understanding of intracranial anatomic and abnormal spatial relationships, 2) simulating the craniotomy and the required cranial base bone work, and 3) simulating intraoperative views. CONCLUSION: The VIVIAN system allows users to work with complex imaging data in a fast, comprehensive, and intuitive manner. The 3-D interaction of this virtual reality environment is essential to the efficient assembly of surgically relevant spatial information from the data derived from multiple imaging techniques. The usefulness of the system is highly dependent on the accurate coregistration of the data and the real-time speed of the interaction.

Adult↗

PubMed1998

Microelectrode-guided functional neurosurgery assisted by Electronic Clinical Brain Atlas CD-ROM.

The Electronic Clinical Brain Atlas is a CD-ROM containing several classic brain atlases and a real-time yet simple registration function that deforms the atlases to match them with specific patient studies. This article presents the use of this registration function for functional neurosurgery planning. We first propose the CD-ROM assisted planning procedure, then illustrate it with two cases: a pallidal stimulation and a thalamic stimulation. The Schaltenbrand-Wahren atlas is registered and scaled to conform with an actual patient's data by means of two-dimensional (2-D) local deformations performed in multiple orientations. First a rectangular region of interest (ROI), which is set between any clearly visible landmarks chosen by the neurosurgeon, is measured on the film or scanner console. The corresponding atlas plate with the target is then deformed in real time for the same landmarks, such that the dimensions of this ROI are the same on the film and on the deformed atlas plate. Next the target is set on the deformed (individualized) atlas plate and its coordinates are read. The individualized atlas plate can also be printed on transparent foil and superimposed on the film or, alternatively, this superimposition can be done electronically. The planning steps can be repeated for all available orientations. The proposed atlas-assisted planning procedure extends the traditional use of printed stereotactic atlases by individualizing them to specific patients. The preliminary results show that this procedure may improve the definition of the target and may have several advantages over other approaches, such as indirect measurements based on the AC-PC line or 1-D (intercommissural distance based) scaling. It provides the neurosurgeon with a convenient and immediate means of accessing ancillary data that is usually only available in the printed form.

Anatomy, Artistic↗

PubMed1998

Anatomical targeting in functional neurosurgery by the simultaneous use of multiple Schaltenbrand-Wahren brain atlas microseries.

This paper presents a novel approach for the use of the Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren [Stuttgart, Thieme, 1977] for anatomical targeting in functional neurosurgery. We propose to use simultaneously all three electronic axial, coronal and sagittal mutually coregistered Schaltenbrand-Wahren brain atlas microseries. The printed atlas microseries are digitized, extended to cover both hemispheres, contoured, labeled, organized into atlas volumes, and mutually coregistered. The electronic atlas is interactively registered with the data by using the three-dimensional Talairach proportional grid system transformation, followed up by local warping in the region of interest based on any clearly visible landmarks. The detailed targeting steps for pallidotomy, thalamotomy and subthalamotomy are formulated. The potential of this approach is to increase the accuracy of target definition, to decrease the time of the procedure by reducing the number of microelectrode tracts, and to give an extra degree of confidence to the neurosurgeon. The advantages of the approach and the limitations of the Schaltenbrand-Wahren atlas are discussed.

Anatomy, Artistic↗

PubMed1998

Stereotactic microelectrode-guided posteroventral pallidotomy and pallidal deep brain stimulation for Parkinson's disease.

Three patients underwent stereotactic posteroventral pallidotomy, and 1 patient underwent pallidal deep brain stimulation, for medically intractable symptoms of advanced Parkinson's disease, characterized by peak-dose levodopa dyskinesias, wearing-off fluctuations, tremor, rigidity and bradykinesia. Surgery was performed stereotactically under local anaesthesia, with eventual target coordinates derived from a combination of magnetic resonance imaging (MRI), coregistration with an electronic brain atlas, intraoperative microelectrode neuronal recordings and microstimulation before lesioning or placement of a deep brain stimulator was done. Assessment was made at baseline preoperatively and at 3-month intervals postoperatively, with Unified Parkinson's Disease Rating Scale (UPDRS) and Core Assessment Program for Intracerebral Transplantation (CAPIT) scoring. All patients improved in dyskinesia, tremor, rigidity and bradykinesia contralateral to the lesion side, but also on the ipsilateral side to a lesser extent. The improvement was largely seen in the 'off' state: UPDRS by 41%, and CAPIT by 19% on the contralateral side. 'On' freezing was not helped. There were no deaths and no visual complications, but there was one complication of a delayed contralateral upper limb dystonia after pallidotomy. The 1 patient with pallidal deep brain stimulation (DBS) obtained similar improvement as those with pallidotomy. Posteroventral pallidotomy and pallidal stimulation improves all the cardinal features of Parkinson's disease, and effectively ameliorates levodopa dyskinesias.

Electric Stimulation Therapy↗

PubMed1997

Multiple brain atlas database and atlas-based neuroimaging system.

For the purpose of developing multiple, complementary, fully labeled electronic brain atlases and an atlas-based neuroimaging system for analysis, quantification, and real-time manipulation of cerebral structures in two and three dimensions, we have digitized, enhanced, segmented, and labeled the following print brain atlases: Co-Planar Stereotaxic Atlas of the Human Brain by Talairach and Tournoux, Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren, Referentially Oriented Cerebral MRI Anatomy by Talairach and Tournoux, and Atlas of the Cerebral Sulci by Ono, Kubik, and Abernathey. Three-dimensional extensions of these atlases have been developed as well. All two- and three-dimensional atlases are mutually preregistered and may be interactively registered with an actual patient's data. An atlas-based neuroimaging system has been developed that provides support for reformatting, registration, visualization, navigation, image processing, and quantification of clinical data. The anatomical index contains about 1,000 structures and over 400 sulcal patterns. Several new applications of the brain atlas database also have been developed, supported by various technologies such as virtual reality, the Internet, and electronic publishing. Fusion of information from multiple atlases assists the user in comprehensively understanding brain structures and identifying and quantifying anatomical regions in clinical data. The multiple brain atlas database and atlas-based neuroimaging system have substantial potential impact in stereotactic neurosurgery and radiotherapy by assisting in visualization and real-time manipulation in three dimensions of anatomical structures, in quantitative neuroradiology by allowing interactive analysis of clinical data, in three-dimensional neuroeducation, and in brain function studies.

Anatomy, Artistic↗

PubMed1997

Functional neurosurgery aided by use of an electronic brain atlas.

The authors present their experience in the use of an atlas-based computer system for preoperative functional neurosurgery planning and postoperative analysis. It has also some potential for intraoperative support. The system is based on a deformable electronic version of "Atlas of Stereotaxy of the Human Brain" by Schaltenbrand and Wahren. This atlas is used for interactive segmentation and labelling of clinical data in two- and three dimensions, and for definition of stereotactic targets. The Schaltenbrand-Wahren atlas microseries are digitized, enhanced, segmented, labelled, aligned and organized into atlas volumes. They are mutually preregistered, and three-dimensional models of the structures are constructed. The atlas may be interactively registered with an actual patient's data. A computer system is developed which provides data interpolation, reformatting, registration, visualization, navigation, mensuration and path display and editing in two- and three dimensions. The system increases the accuracy of target definition, reduces the time of planning and the time of the procedure itself. It also constitutes a research platform for the construction of more advanced neurosurgery supporting tools and brain atlases.

Brain↗

PubMed1997

The Brain Bench: virtual tools for stereotactic frame neurosurgery.

We present a suite of neurosurgery supporting tools developed around (i) the Virtual Workbench, a productive environment for the control of 3-D data, in which delicate work can be performed for hours on end without strain, and (ii) the Electronic Brain Atlas, integrating the major print brain atlases in day-to-day clinical use. We describe in detail the Brain Bench, a surgical planning system for stereotactic frame neurosurgery. Its objective is to prepare faster plans; have a better and more accurate choice of target points; improve the avoidance of sensitive structures; have fewer sub-optimal frame attachments and speedier, more effective planning and training. If validated by a clinical study now under way, this will improve medical efficacy and reduce costs.

Brain↗

PubMed1997

Exploring the human brain using single-unit microelectrode technique during awake stereotactic functional neurosurgery.

In neuroscience research, the use of true single-unit microelectrode technique has been confined largely to the animal neurophysiology laboratory due to the complexity of the equipment required and the fastidious, time-consuming nature of the methodology. We report here our successful clinical use of this technique in human patients with Parkinson's disease undergoing awake stereotactic movement disorder neurosurgery. The common targets in such operations are the postero-ventral portion of the globus pallidus interna in the basal ganglia (for dopa-induced dyskinesias particularly) and the ventro-intermediate nucleus of the thalamus (for tremor-predominant Parkinson's disease). Accurate and exquisite neurophysiological localisation of these small targets deep within the brain can be obtained with single-unit microelectrode technique prior to the insertion of a deep brain stimulator or definitive neurosurgical radiofrequency lesioning in the target area. This accuracy translates into better outcomes for patients and a reduced incidence of complications. The wealth of data gained from studying the abnormal behaviour of neurons within the basal ganglia and thalamus also provides us with fundamental insights into the pathophysiology behind Parkinson's disease.

Basal Ganglia↗