Specific In Vivo Staining of Astrocytes in the Whole Brain after Intravenous Injection of Sulforhodamine Dyes

Fluorescent staining of astrocytes without damaging or interfering with normal brain functions is essential for intravital microscopy studies. Current methods involved either transgenic mice or local intracerebral injection of sulforhodamine 101. Transgenic rat models rarely exist, and in mice, a backcross with GFAP transgenic mice may be difficult. Local injections of fluorescent dyes are invasive. Here, we propose a non-invasive, specific and ubiquitous method to stain astrocytes in vivo. This method is based on iv injection of sulforhodamine dyes and is applicable on rats and mice from postnatal age to adulthood. The astrocytes staining obtained after iv injection was maintained for nearly half a day and showed no adverse reaction on astrocytic calcium signals or electroencephalographic recordings in vivo. The high contrast of the staining facilitates the image processing and allows to quantify 3D morphological parameters of the astrocytes and to characterize their network. Our method may become a reference for in vivo staining of the whole astrocytes population in animal models of neurological disorders

Deformable Modeling of Facial Tissue for Craniofacial Surgery Simulation

While deformable object modeling has been studied in computer graphics for more than two decades, only a few applications in surgical simulation have been developed which provide both real-time and physically realistic modeling of complex, non-linear, tissue deformations. Especially in craniofacial surgery the prediction of soft tissue changes- which are the result of the alteration of the underlying bone structure- is critical to the surgical outcome. Up until today the prediction of these tissue changes, and therefore the prognosis of the postoperative appearance of the patient, is still based on empirical studies of the relationship between bone and tissue movements: There exist no physical model, which takes into account the individual patient anatomy in order to simulate the resulting tissue changes during craniofacial surgery. In this article we present two different deformable tissue models, which are integrated in an interactive surgical simulation testbed. Both techniques allow the precise preoperative simulation of the resulting soft tissue changes during craniofacial surgery and the visualization of the patientÕs postoperative appearance. The different deformable models are described in detail and both are applied to the same craniofacial case study. The simulation results are shown and compared with regard to the speed and accuracy of the prediction of the patient's postoperative appearance

Computer Aided Diagnosis of Bone Lesions in the Facial Skeleton

. We present a system for computer aided diagnosis of bone tumors in the facial skeleton. There are many different lesions with radiographic manifestation in the jaws. Our system helps performing the differential diagnosis of these. The input is a digitized orthopantomograph (OPG) in which the user marks the position of the lesion with a single mouse click. An active contour model then automatically finds the boundaries of the lesion. Gray-level histograms, MRSAR texture features and Gabor filter features are computed for the lesion region. These features are then combined and used to query a database containing expert-diagnosed reference cases. The result is a number of similar cases, with tumor position marked and with available expert annotations. We show good agreement between our results and differential diagnosis given by humans. The system is also a suitable tool for training and education. Keywords: Computer aided diagnosis, content based image retrieval 1 Introduction Bone ..

Anatomy-based facial tissue modeling using the finite element method

surgery planning and simulation Abstract: Anatomy-based facial tissue modeling for surgical simulation is a field whose time has come. Real-time facial animation has been created in the last few years using models based on the anatomical structure of the human skin. Anatomy-based models are also under development in the field of medical visualization, with which facial surgery can be realistically simulated. In this article we present an anatomy-based 3D finite element tissue model. Integrated into a computer-aided surgical planning system this model allows the precise prediction of soft tissue changes resulting from the realignment of the underlying bone structure. The model has already been used in our Department of Oral and Maxillofacial Surgery and has improved craniofacial surgical planning procedures. The model is described in detail and surgical simulation results are shown and discussed. 1

Special Issue of Signal Processing on Medical Image Compression 1997 Adaptive Surface Data Compression

Abstract: Three-dimensional visualization techniques are becoming an important tool for medical applications. Computer generated 3D reconstructions of the human skull are used to build stereolithographic models, which can be used to simulate surgery or to create individual implants. Anatomy-based three-dimensional models are used to simulate the physical behaviour of human organs. These 3D models are usually displayed by a polygonal description of their surface, which requires hundreds of thousands of polygons. For interactive applications this large of number polygons is a major obstacle. We have improved an adaptive compression algorithm that significantly reduces the number of triangles required to model complex objects without losing visible detail and have implemented it in our surgery simulation system. We present this algorithm using human skull and skin data and describe the efficiency of this new approach. Zusammenfassung: Computerbasierte dreidimensionale Visualisierungstechniken haben im letzten Jahrzehnt Einzug in die Medizin gehalten. Aus den computergenerierten dreidimensionalen Rekonstruktionen des Gesichtsschädels werden unter anderem mittels Stereolithographie reale Modelle erstellt, an denen geplante chirurgische Eingriffe simuliert werden können, oder aber die 3D-Rekonstruktionen dienen dazu, patientenangepaßte Implantate herzustellen. Die Geometrie solc