A new representation of knowledge concerning human anatomy and function.

By integrating concepts of computer graphics and artificial intelligence, novel ways of representing medical knowledge become possible. They allow unprecedented possibilities ranging from three-dimensional interactive atlases to systems for surgery rehearsal.

[Breach of secrecy by handing out psychiatric certificates]. / Schweigepflichtsverletzung durch Weitergabe psychiatrischer Atteste. Zu den Grenzen arztlichen Handelns und zur Rolle der Ehefrau im psychiatrischen Kontext.

The article reports about a medical malpractice case against the director of a psychiatric University Hospital, who was convicted for breach of secrecy by the Oberlandesgericht in Munich. The court found him guilty of issuing and giving to the plaintiff's wife an unauthorised psychiatric certificate, stating that the plaintiff, a carpet dealer for oriental rugs, who was caught in a war of roses with his wife at this time and was never a patient of the psychiatrist, let alone properly examined by him or his staff, suffered from an acute and severe psychosis with immediate need for compulsory admission. This all happened behind his back and enabled the wife to spread rumors of the alleged mental illness of her husband. Banks and trading partners therefore shunned him, which nearly caused his bankruptcy. This is why this unusual case led to the decision that the psychiatrist had to reimburse Euro 15000 for pain and suffering and additionally cover all material damages resulting from the tort.

[Obligatory informed consent on the risks to the accommodation ability of the eye after the implantation of an artificial lens]. / Verlust der Akkomodationsfähigkeit beim Einsetzen einer Kunstlinse ist aufklärungspflichtig.

The article reports a medical malpractice claim in Germany against an ophthalmologist who implanted an artificial lens without informing the patient about the risk of losing the eye's accommodation ability before undertaking surgery. As informed consent was not obtained, in spite of the obligation to so, the court ruled that the physician should pay compensation for medical malpractice. The author shows how similar malpractice cases can be prevented in future.

A computerized three-dimensional atlas of the human skull and brain.

PURPOSE: To develop an anatomic atlas of the human head based on a volume model derived from MR and CT. METHODS: Every voxel of this model was labeled by a neuroanatomist concerning its membership to a structural and/or functional region. A computer program was written that, instead of displaying precomputed images, allows the user to choose and compose arbitrary views. RESULTS: The user can subtract parts and ask for annotations just by using the mouse. Conversely, one can compose images by choosing objects from the list of anatomical constituents which is displayed on the screen. A set of dissection tools allows a "look and feel" that comes near to a true dissection. Operations that are not possible in a real dissection, such as reassembly or filling cavities, can be performed. CONCLUSION: The authors have developed a computerized model that can be used for anatomy teaching and also as a reference for radiologists or surgeons. To replace classical atlases, the spatial resolution must be improved and speed must approach real time. Functional imaging data (position emission tomography and single photon emission CT) can be added to the system. The system is mobile and can be situated in classrooms, operating rooms, reading rooms, and libraries.

Data compression in digital angiography using the Fourier transform.

While digital techniques in radiology develop rapidly, problems arise with archival storage and communication of image data. This paper reports on experiments concerning data reduction of digital image sequences of the heart and the brain. The time-intensity curves corresponding to every picture element are subjected to the Fourier transform and reconstructed from a number of coefficients smaller than the original number of images. The reconstruction error is assessed by visual inspection and by determining the mean-square deviation of the original and the reconstructed curve. It is shown that compression factors between 5 and 10 may be achieved without loss of diagnostic information. It is furthermore demonstrated that storage of the images in the form of Fourier coefficients leads to advantages in fast retrieval, enhancement of morphology, and possibility of further quantitative analysis.

Vascular leucocyte adhesion molecules unaltered in the human retina in diabetes.

BACKGROUND/AIMS: Capillary occlusion is believed to have a critical role in the development of diabetic retinopathy (DR). The exact mechanism by which it occurs, however, remains unclear. Several in vitro and animal model studies have suggested increased adhesion of leucocytes to the endothelium via upregulated ICAM-1 on the retinal microvasculature as a possible mechanism. In this comparative immunohistochemical study the expression of ICAM-1 was compared in the retinal vasculature of 41 eyes obtained from 37 diabetic people with 19 eyes from 19 non-diabetic controls. METHODS: Serial cryosections of postmortem posterior tissue from 41 diabetic eyes and 19 non-diabetic eyes were stained with the monoclonal antibodies ICAM-1 (two clones), CD31(panendothelial marker), and PAL-E (vascular leakage marker). RESULTS: A similar pattern of vascular ICAM-1 staining was observed between diabetic and non-diabetic eyes. A diffuse ICAM-1 staining of the retina was also observed that was significantly more intense in the diabetic subjects (p = 0.001). CONCLUSION: These results indicate that ICAM-1 is constitutively expressed on retinal and choroidal vasculature of non-diabetic, control subjects and that this level of expression is not significantly altered by the diabetic environment. Taken together, these results do not support the prevalent paradigm of increased adhesion molecule expression as a primary mechanism responsible for capillary occlusion reported in diabetic individuals.

3-D segmentation of MR images of the head for 3-D display.

Algorithms for 3-D segmentation and reconstruction of anatomical surfaces from magnetic resonance imaging (MRI) data are presented. The 3-D extension of the Marr-Hildreth operator is described, and it is shown that its zero crossings are related to anatomical surfaces. For an improved surface definition, morphological filters-dilation and erosion-are applied. From these contours, 3-D reconstructions of skin, bone, brain, and the ventricular system can be generated. Results obtained with different segmentation parameters and surface rendering methods are presented. The fidelity of the generated images comes close to anatomical reality. It is noted that both the convolution and the morphological filtering are computationally expensive, and thus take a long time on a general-purpose computer. Another problem is assigning labels to the constituents of the head; in the current implementation, this is done interactively.

Fourier domain techniques for digital angiography of the heart.

Digital angiography is widely considered simply as a method in which images taken at different times are subtracted from each other. This paper presents some techniques which are performed in the frequency domain after the application of the Fourier transform. Nonselective bypass angiograms and intravenous ventriculograms are taken as examples to show that simple procedures utilizing these techniques exhibit the advantages of improved signal-to-noise ratio in the subtraction images, reduction of motion artifacts, easy application of phase-synchronous subtraction, integration, and quantitative visualization of blood propagation. It is furthermore shown that the storage of the angiographic image sequence as Fourier coefficients leads to data compression and convenient data access in an image database.

Creating a high-resolution spatial/symbolic model of the inner organs based on the Visible Human.

Computerized three-dimensional models of the human body, based on the Visible Human Project of the National Library of Medicine, so far do not reflect the rich anatomical detail of the original cross-sectional images. In this paper, a spatial/symbolic model of the inner organs is developed, which is based on more than 1000 cryosections and congruent fresh and frozen CT images of the male Visible Human. The spatial description is created using color-space segmentation, graphic modeling, and a matched volume visualization with subvoxel resolution. It is linked to a symbolic knowledge base, providing an ontology of anatomical terms. With over 650 three-dimensional anatomical constituents, this model offers an unsurpassed photorealistic presentation and level of detail. A three-dimensional atlas of anatomy and radiology based on this model is available as a PC-based program.

[3-dimensional display of computed tomographic studies of craniofacial anomalies]. / Die dreidimensionale Darstellung computertomographischer Untersuchungen kraniofazialer Anomalien.

Craniofacial anomalies are conventionally investigated by cephalometry using ordinary radiographs and by computed tomography. Both methods have the major disadvantage of trying to demonstrate a complex three-dimensional structure, such as the skull, in two dimensions and they therefore cannot display a true spatial image. We present the principle underlying a three-dimensional display derived from computer tomographic studies and discuss the clinical application in the diagnosis of craniofacial anomalies.

[Applicability of digital methods in x-ray diagnosis]. / Anwendungsmöglichkeiten digitaler Methoden in der Röntgendiagnostik.

The significance of digital examination methods continues to grow. Since the introduction of computer tomography, two additional digital imaging modalities-digital subtraction angiography (DSA) and magnetic resonance imaging (MRI)--have been developed. In this paper we present basic techniques of computerized image processing and outline foreseeable future developments. Furthermore, we discuss the possibilities and problems presented by digital picture archiving and communication systems (PACS).

A realistic model of human structure from the visible human data.

The computer-based 3D models of the human body reported to date suffer from poor spatial resolution. The Visible Human project has delivered high resolution cross-sectional images that are suited for generation of high-quality models. Yet none of the 3D models described to date reflect the quality of the original images. We present a method of segmentation and visualization which provides a new quality of realism and detail. Using the example of a 3D model of the inner organs, we demonstrate that such models, especially when combined with a knowledge base, open new possibilities for scientific, educational, and clinical work.

A new method for representing the human anatomy.

In current practice, anatomical atlases are based on a collection of planar images presented in a book or, recently, stored on digital media. We present a new method for generating interactive true three-dimensional (3D) anatomical atlases based on a volume model derived from MRI and CT. The model has a two layer structure. The lower level is a volume model with a set of semantic attributes connected to each voxel. The semantic attributes are assigned by an anatomist using a volume editor. The upper level is a set of relations between these attributes. Interactive visualization tools such as multiple surface display, transparent rendering, and cutting are provided. It is shown that the combination of this data structure with advanced volume visualization tools provides the "look and feel" of real dissection. First tests show that the atlas system cannot only be used successfully for anatomy teaching, but also as a reference for radiologists or surgeons. As a replacement of classical atlases, however, the spatial resolution has still to be improved.

Exploring the Visible Human using the VOXEL-MAN framework.

In principle the Visible Human data sets are an ideal basis for building electronic atlases. While it is easy to construct such atlases by just offering the possibility of browsing through the 2D slices, constructing realistic 3D models is a huge project. As one rather easy way to establish 3D use, we have registered the Visible Human data to the already existing 3D atlas VOXEL-MAN/brain. This procedure enables one to lookup anatomical detail in an atlas based on radiological images. Concerning the segmentation problem, which is the prerequisite for a real 3D atlas, we have developed an interactive classification method that delivers realistic perspective views of the Visible Human. As these volume based methods require high-end workstations, we finally have developed a multimedia program that runs on standard PCs and uses Quicktime VR movies.

[Classification of the germinal epithelium in Java monkeys (Macaca cynomolgus) using digital image processing]. / Untersuchung zur Gliederung des Keimepithels beim Javaneraffen (Macaca cynomolgus) mittels digitaler Bildverarbeitung.

Testicular tissue of two adult crab-eating macaques was used to investigate the distribution of the spermatids in the seminiferous tubules. For this purpose, morphological criteria for distinction among the various degrees of development of these cells were elaborated. Subsequently, based upon analyses of serial sections, three-dimensional reconstructions of the cellular distribution pattern were generated by means of digital image processing. In these reconstructions it became evident that the spatial extension of a single differentiation stage can vary considerably. Large tubular portions that contained a single differentiation stage alternated with those exhibiting several differentiation stages which occupied only small patch-like areas of the seminiferous epithelium. Particularly in the latter portions of the tubule a helical continuity of subsequent stages in the sense of a wave of spermatogenesis became immediately obvious. Transitory changes in the direction of the wave (modulations) occurred frequently. The present findings support the suggestion that an uniform kinetic principle of mammalian spermatogenesis exists, which is subjected to slight modifications during the evolution of primates.

Exploring the visible human's inner organs with the VOXEL-MAN 3D navigator.

Improved rendering and segmentation techniques lead to a new quality of 3D reconstructions of the Visible Human. Using these we have implemented an interactive atlas of anatomy and radiology of the inner organs.

Interactive volume visualization using "intelligent movies".

High quality visualization of medical volume models as performed by the VOXEL-MAN and similar systems is still too time consuming and the interaction complicated when sophisticated tools like dissection are used. We hence developed a new paradigm allowing to create simpler derivatives of the model, called "intelligent movies". These are in QuickTime or QuickTime VR format which allow interactive exploration with two degrees of freedom. As a decisive novelty, we extended it by a pixelwise link to the knowledge base which may be queried in the image context. Thus scenes emphasizing a selected aspect of the volume model may be created as intelligent movies, which a user (referring physician, student) can explore largely with the functionality of VOXEL-MAN, but in real time--on any standard PC--and also via a JAVA applet within web browsers. This is shown with the example of 3D interactive anatomical atlases and clinical cases.

[UV Protection Law. Enhancing the protection of minors against health risks from solaria]. / UV-Schutzgesetz. Besserer Schutz Minderjähriger vor Gesundheitsschäden durch Solarien.

The article reports on a petition to the German Bundestag in the field of UV protection for persons under the age of 18 against the dangers of artificial sunbed tanning for cosmetic purposes. On 16 March 2006 the Parliament agreed to adopt the proposal of the author, after the Ministry of Environment announced it is working on a UV Protection Law for Germany. Furthermore the committee recommended the petition to the government and the parliamentary parties. The UV Protection Law is still in progress, and no draft has yet been published. Therefore, the author explains the difficulties in creating such law from a legal and a public health perspective, pointing out that the split of competence between the federation and the states poses difficulties. He concludes that the German Constitution would allow a sunbed prohibition for minors in public studios and explains why a complete prohibition for the adult population would be disproportionate and unconstitutional.

A novel interactive anatomic atlas of the hand.

Classical anatomic atlases cannot provide the spectrum of views and the detail required in modern diagnostic and surgical techniques. Computer modeling opens the possibility to choose any view from one single model. A computerized model of the hand is presented, which has been obtained by segmentation and graphic modeling of the Visible Human dataset. In addition to being able to choose arbitrary viewpoints, it allows interrogation of the chosen views by mouse click. We believe the functions of these new kinds of atlases are superior to the classical ones.