Anatomical Template Research Articles

Should patients with muscle-invasive bladder cancer undergo more-extensive pelvic lymph node dissection?

This Practice Point commentary discusses the paper by Dhar and colleagues, which compared outcomes between two cohorts of patients with muscle-invasive bladder cancer who received either 'limited' pelvic lymph node dissection (LND) or 'extended' pelvic LND at clinics in the US or Switzerland. The patients who received extended LND demonstrated improved overall and recurrence-free survival. Notably, however, the 'extended' and 'limited' dissections utilized in this study do not correspond to the commonly used anatomical templates defined by these terms. Nonetheless, despite this and other methodological limitations, this study does add to the growing evidence supporting the use of more-extensive pelvic LND in this setting. One prospective, randomized trial aiming to address this issue is currently accruing patients in Germany. While results are awaited, extended LND should be regarded as an essential component of radical cystectomy and applied to all patients undergoing radical surgery for bladder cancer.

Basal Ganglia Shape Abnormalities in the Unaffected Siblings of Schizophrenia Patients

Abnormalities of basal ganglia structure in schizophrenia have been attributed to the effects of antipsychotic drugs. Our aim was to test the hypothesis that abnormalities of basal ganglia structure are intrinsic features of schizophrenia by assessing basal ganglia volume and shape in the unaffected siblings of schizophrenia subjects. The study involved 25 pairs of schizophrenia subjects and their unaffected siblings and 40 pairs of healthy control subjects and their siblings. Large-deformation, high-dimensional brain mapping was used to obtain surface representations of the caudate, putamen, and globus pallidus. Surfaces were derived from transformations of anatomic templates, and shapes were analyzed using reduced-dimensional measures of surface variability (i.e., principal components and canonical analysis). Canonical functions were derived using schizophrenia and control groups and were then used to compare shapes in the sibling groups. To visualize shape differences, maps of the estimated surface displacement between groups were created. In the caudate, putamen, and globus pallidus, the degree of shape abnormality observed in the siblings of the schizophrenia subjects was intermediate between the schizophrenia and control subjects. In the schizophrenia subjects, significant correlations were observed between measures of caudate, putamen, and globus pallidus structure and the selected measures of lifetime psychopathology. Attenuated abnormalities of basal ganglia structure are present in the unaffected siblings of schizophrenia subjects. This finding implies that basal ganglia structural abnormalities observed in subjects with schizophrenia are at least in part an intrinsic feature of the illness.

Atlas guided navigation of brain image repositories using NeuroTerrain

Event Abstract Back to Event Atlas guided navigation of brain image repositories using NeuroTerrain Jonathan Nissanov1*, Carl Gustafson1, Pablo D. Burstein1 and Louise Bertrand1 1 Drexel University College of Medicine, United States Access to a repository of brain imagery can be made efficient if the data is annotated, spatially normalized, or both. If the transformation mapping points between library entries and reference spatial coordinates is known, then one can retrieve relevant views from multiple brain volumes based on coordinate specification. If the volumes are annotated, retrieval can rely on anatomical labels. This presentation will focus on use of NeuroTerrain, an atlas-browsing environment [1], to selectively view desired planes from the Mouse Brain Library (MBL) [2], an image repository containing 2D brain images. MBL contains images of histological sections from a large number of mice strains. It was specifically design for functional genomics mapping studies. NeuroTerrain utilizes a reference 3D mouse brain atlas and was developed to serve as MBL’s spatial index. Once entries in the library are aligned to the Atlas, bidirectional spatial navigation is possible–one can automatically display arbitrary planes of view in the atlas corresponding to given MBL entry as well as retrieve entries in the library matching a given atlas plane. Registration between atlas and MBL entries also enables automatic annotation of the latter using Atlas anatomical templates and work is ongoing to support label-based navigation. NeuroTerrain also supports co-navigation of aligned 3D volumes: arbitrary planes of view selected in one invokes selection of the equivalent planes in the others. The collection of open volumes can also share available delineation templates and the desired set of volumes of interest can be visualized overlaying each of them. NeuroTerrain is composed of a server and light Java client. The server generates arbitrary slices of 3D volumes including those of the atlas and its anatomical templates. The client provides the user interface to control navigation and to visualize the results. The client can be readily instantiated in other Java applications. This greatly simplifies migration of these capibilities into diverse analysis and visualization environments.

Robust brain registration using adaptive probabilistic atlas.

Elastic image registration is widely used to adapt brain images to a common template space, and, in complementary fashion, to adapt an anatomical template to a subject's anatomy. Although HAMMER is a very accurate image-registration algorithm, it requires a 3-class segmentation step prior to registration, and its performance is affected by segmentation quality. We here propose a new framework to improve this algorithm's robustness to poor initial segmentation. Our new framework is based on Adaptive Generalized Expectation Maximization (AGEM) for unified segmentation and registration, in which we use an adaptive strategy to incorporate spatial information from a probabilistic atlas to improve segmentation and registration simultaneously. Our experiments using real MR brain images indicate that our integrated approach improves registration accuracy; we have also found that our iterative approach renders HAMMER robust to low tissue contrast, which hinders 3-class segmentation.

Dealing with the shortcomings of spatial normalization: Multi‐subject parcellation of fMRI datasets

The analysis of functional magnetic resonance imaging (fMRI) data recorded on several subjects resorts to the so-called spatial normalization in a common reference space. This normalization is usually carried out on a voxel-by-voxel basis, assuming that after coregistration of the functional images with an anatomical template image in the Talairach reference system, a correct voxel-based inference can be carried out across subjects. Shortcomings of such approaches are often dealt with by spatially smoothing the data to increase the overlap between subject-specific activated regions. This procedure, however, cannot adapt to each anatomo-functional subject configuration. We introduce a novel technique for intra-subject parcellation based on spectral clustering that delineates homogeneous and connected regions. We also propose a hierarchical method to derive group parcels that are spatially coherent across subjects and functionally homogeneous. We show that we can obtain groups (or cliques) of parcels that well summarize inter-subject activations. We also show that the spatial relaxation embedded in our procedure improves the sensitivity of random-effect analysis.

Neurophysiological Architecture of Functional Magnetic Resonance Images of Human Brain

We investigated large-scale systems organization of the whole human brain using functional magnetic resonance imaging (fMRI) data acquired from healthy volunteers in a no-task or 'resting' state. Images were parcellated using a prior anatomical template, yielding regional mean time series for each of 90 regions (major cortical gyri and subcortical nuclei) in each subject. Significant pairwise functional connections, defined by the group mean inter-regional partial correlation matrix, were mostly either local and intrahemispheric or symmetrically interhemispheric. Low-frequency components in the time series subtended stronger inter-regional correlations than high-frequency components. Intrahemispheric connectivity was generally related to anatomical distance by an inverse square law; many symmetrical interhemispheric connections were stronger than predicted by the anatomical distance between bilaterally homologous regions. Strong interhemispheric connectivity was notably absent in data acquired from a single patient, minimally conscious following a brainstem lesion. Multivariate analysis by hierarchical clustering and multidimensional scaling consistently defined six major systems in healthy volunteers-- corresponding approximately to four neocortical lobes, medial temporal lobe and subcortical nuclei- - that could be further decomposed into anatomically and functionally plausible subsystems, e.g. dorsal and ventral divisions of occipital cortex. An undirected graph derived by thresholding the healthy group mean partial correlation matrix demonstrated local clustering or cliquishness of connectivity and short mean path length compatible with prior data on small world characteristics of non-human cortical anatomy. Functional MRI demonstrates a neurophysiological architecture of the normal human brain that is anatomically sensible, strongly symmetrical, disrupted by acute brain injury, subtended predominantly by low frequencies and consistent with a small world network topology.

Brain Perfusion Abnormalities in Neurologically Asymptomatic Adult Patients with Sickle Cell Disease. A Voxel-Based Analysis of Brain Spect Imaging.

Sickle cell diseases (SCD) are characterized by the presence of hemoglobin S, hemolytic anemia and vascular occlusion. Silent infarcts in SCD patients is strongly associated with an increased stroke risk and progressive cognitive decline. In this study we used 99mTc-ECD single photon emission computerized tomography (SPECT) in order to detect early abnormalities of brain perfusion in neurologically asymptomatic adult SCD patients. We recruited 42 SCD (27 females and 15 males, mean age of 33.4±10.55, range 17–60 years) from the Hematology and Hemotherapy Center of the University of Campinas.The SCD types were distributed as follows: 33 HbSS (14 males and 19 females), 6 HbSC (1 male and 5 females) and 3 HbSBeta (3 females). Mean steady state hemoglobin level measured in the period of up to 2 weeks before or after imaging acquisition was 8.5g/dl (±1.73; 5.2–13.5) and mean hematocrit was 25.1% (±4.85; 15.6–38.5). The group of patients with SCD was compared to a group of control healthy subjects (29 females and 20 males with mean age 31 years ±8; 25–49) recruited within the local community, who were submitted to the same imaging protocol used in the patients.The study was approved by the National Ethical Committee Board and informed-write consent was obtained from all patients. The inclusion criteria for this study was to be at least 17 years old, have a precise clinical and laboratory diagnosis of any SCD, do not have stroke previously and be on regular follow-up in the clinic. All of them were submitted to a standard protocol of brain SPECT image acquisition. Reconstructed transaxial datasets were converted into ANALYZE format and corrected for the orthogonal plane of acquisition using MRIcro software. Voxel-based analysis was performed using SPM2 (Wellcome Department of Cognitive Neurology). Images were spatially normalized to standard anatomical template defined in the atlas of Talairach and Tournoux. The normalized smoothed images underwent group comparison of regional tracer uptake using paired t-test. Contrasts were defined in order to estimate the probability of each voxel to have an increased or decreased tracer uptake in images from patients with SCD compared to images from the normal control group. Reduced tracer uptake was observed in many areas of the brain when compared to normal controls. These areas corresponded predominantly to watershed regions and other brain areas supplied by micro vasculature. We observed a reduced tracer uptake in the central basal forebrain, which includes the basal ganglia and thalami, the anterior frontal region and the watershed region of the temporo-parietal-occipital transition. These regions are to be considered the most significant hypoperfused areas (false discovery rate correction of p<0.05).The findings of our study demonstrate that neurologically asymptomatic SCD patients exhibit a pattern of reduced 99mTc-ECD tracer uptake demonstrated by SPECT. Early diagnosis of such cerebral vasculopathy has prognostic implications and can be determinant in considering therapeutic alternatives to avoid increasing in brain lesion load and progressive disability.

Vascular territories and watersheds: a zonal frequency analysis of the gyral and sulcal extent of cerebral infarcts. Part I: the anatomic template.

Our purpose was to establish a template of upper cerebral anatomy suitable for analysis of infarct distribution and for comparison among infarct types. We made a standard diagram of the key gyri and sulci of the supraventricular and occipital regions, partitioned the gray matter and white matter into specific zones useful for analyzing infarcts by CT and MRI, and numbered each zone uniquely in to establish a template suitable for tabulating the precise regions affected by each infarct and for analyzing differences among infarcts. The template provides a method for extracting a standardized set of data from CT or MRI performed at any angle, reconfiguring those data into a standard image, and characterizing the specific portions of infarcted brain in terms of unique numbers suitable for tabulation, collation and comparison. Standardization of the format provides for later computer analysis of increasing numbers of diverse infarcts. This method may be extended to any other type of pathology, although successful analysis of different lesions may require partitioning the gray and white matter zones in different ways.

WTC and the OTHER

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

Spatial Normalization and Averaging of Diffusion Tensor MRI Data Sets

Diffusion tensor magnetic resonance imaging (DT-MRI) is unique in providing information about both the structural integrity and the orientation of white matter fibers in vivo and, through “tractography”, revealing the trajectories of white matter tracts. DT-MRI is therefore a promising technique for detecting differences in white matter architecture between different subject populations. However, while studies involving analyses of group averages of scalar quantities derived from DT-MRI data have been performed, as yet there have been no similar studies involving the whole tensor. Here we present the first step towards realizing such a study, i.e., the spatial normalization of whole tensor data sets. The approach is illustrated by spatial normalization of 10 DT-MRI data sets to a standard anatomical template. Both qualitative and quantitative approaches are described for assessing the results of spatial normalization. Techniques are then described for combining the spatially normalized data sets according to three definitions of average, i.e., the mean, median, and mode of a distribution of tensors. The current absence of, and hence need for, appropriate statistical tests for comparison of results derived from group-averaged DT-MRI data sets is then discussed. Finally, the feasibility of performing tractography on the group-averaged DT-MRI data set is investigated and the possibility and implications of generating a generic map of brain connectivity from a group of subjects is considered.

Spatial Normalization and Averaging of Diffusion Tensor MRI Data Sets

Diffusion tensor magnetic resonance imaging (DT-MRI) is unique in providing information about both the structural integrity and the orientation of white matter fibers in vivo and, through “tractography”, revealing the trajectories of white matter tracts. DT-MRI is therefore a promising technique for detecting differences in white matter architecture between different subject populations. However, while studies involving analyses of group averages of scalar quantities derived from DT-MRI data have been performed, as yet there have been no similar studies involving the whole tensor. Here we present the first step towards realizing such a study, i.e., the spatial normalization of whole tensor data sets. The approach is illustrated by spatial normalization of 10 DT-MRI data sets to a standard anatomical template. Both qualitative and quantitative approaches are described for assessing the results of spatial normalization. Techniques are then described for combining the spatially normalized data sets according to three definitions of average, i.e., the mean, median, and mode of a distribution of tensors. The current absence of, and hence need for, appropriate statistical tests for comparison of results derived from group-averaged DT-MRI data sets is then discussed. Finally, the feasibility of performing tractography on the group-averaged DT-MRI data set is investigated and the possibility and implications of generating a generic map of brain connectivity from a group of subjects is considered.

Flumazenil Binding and Cortical Malformations

Central Benzodiazepine Receptors in Malformations of Cortical Development: A Quantitative StudyHammers A, Koepp MJ, Richardson MP, Labbe C, Brooks DJ, Cunningham VJ, Duncan JBrain 2001;124:1555–1565PurposeWe calculated [11C]flumazenil volume of distribution ([11C]FMZ-Vd] after correction for partial volume effect in 10 patients with malformations of cortical development (MCDs) and partial seizures, to quantify the γ-aminobutyric acid (GABAA)-central benzodiazepine receptor complex.MethodsAbnormal grey matter and adjacent or overlying cortex were outlined individually and added to an individualized anatomic template for correction for partial volume effect.ResultsNine of 10 patients showed single or multiple increases or decreases in [11C]FMZ-Vd in or around MCDs. Two of three patients with band heterotopia showed multiple increases in the overlying cortex. In three of four patients with subependymal nodular heterotopia, nodules had lower [11C]FMZ-Vd than the overlying cortex, which was normal. Decreases i...

Flumazenil Binding and Cortical Malformations.

Central Benzodiazepine Receptors in Malformations of Cortical Development: A Quantitative Study Hammers A, Koepp MJ, Richardson MP, Labbe C, Brooks DJ, Cunningham VJ, Duncan J Brain 2001;124:1555–1565 Purpose We calculated [11C]flumazenil volume of distribution ([11C]FMZ-Vd] after correction for partial volume effect in 10 patients with malformations of cortical development (MCDs) and partial seizures, to quantify the γ-aminobutyric acid (GABAA)-central benzodiazepine receptor complex. Methods Abnormal grey matter and adjacent or overlying cortex were outlined individually and added to an individualized anatomic template for correction for partial volume effect. Results Nine of 10 patients showed single or multiple increases or decreases in [11C]FMZ-Vd in or around MCDs. Two of three patients with band heterotopia showed multiple increases in the overlying cortex. In three of four patients with subependymal nodular heterotopia, nodules had lower [11C]FMZ-Vd than the overlying cortex, which was normal. Decreases in [11C]FMZ-Vd were found in two of three clefts and one of six adjacent regions in one schizencephalic patient; another had normal [11C]FMZ-Vd in the thickened cortex itself but increases in all adjacent regions. Binding was reduced within focal cortical dysplasia but increased in adjacent cortex. [11C]FMZ-Vd was normal within one patient's polymicrogyric cortex but increased in one of six adjacent volumes of interest. The localization of abnormalities correlated with EEG and clinical data in cortical MCDs. Conclusions Flumazenil binding was decreased in some MCDs with increased grey-matter volume and increased in some adjacent or overlying areas of normal-appearing cortex, suggesting functional abnormalities beyond magnetic resonance imaging (MRI)-detectable structural changes.

Implementation and application of a brain template for multiple volumes of interest

We present a region template and a protocol for transforming that template to define anatomical volumes of interest (VOIs) in the human brain without operator intervention, based on software contained in the SPM99 package (Statistical Parametric Mapping, Wellcome Department of Cognitive Neurology, London, UK). We used an MRI of a reference brain to create an anatomical template of 41 VOIs, covering the entire brain, that can be spatially transformed to fit individual brain scans. Modified software allows for the reslicing and adaptation of the transformed template to any type of coregistered functional data. Individually defined VOIs can be added. We present an assessment of the necessary spatial transformations and compare results obtained for scans acquired in two different orientations. To evaluate the spatial transformations, 11 landmarks distributed throughout the brain were chosen. Euclidean distances between repeat samples at each landmark were averaged across all landmarks to give a mean difference of 1.3 plus minus 1.0 mm. Average Euclidean distances between landmarks (MRI:transformed template) were 8.1 plus minus 3.7 mm in anterior-posterior commissure (ACPC) and 7.6 plus minus 3.7 mm in temporal lobe (TL) orientation. In this study, we use [(11)C]-flumazenil-(FMZ-)PET as an example for the application of the region template. Thirty-four healthy volunteers were scanned, 21 in standard ACPC orientation, 13 in TL orientation. All had high resolution MRI and FMZ-PET. The average coefficient of variation (CV) of FMZ binding for cortical regions was 0.15, comparable with CVs from manually defined VOIs. FMZ binding was significantly different in 6/19 anatomical areas in the control groups obtained in the different orientations, probably due to anisotropic voxel dimensions. This new template allows for the reliable and fast definition of multiple VOIs. It can be used for different imaging modalities and in different orientations. It is necessary that imaging data for groups compared are acquired in the same orientation.

Functional Inferences Vary with the Method of Analysis in fMRI

Neuroanatomic substrates of specific cognitive functions have been inferred from anatomic distributions of activated pixels during fMRI studies. With declarative memory tasks, interest has focused on the extent to which various medial temporal lobe anatomic structures are activated while subjects encode new information. The aim of this project was to examine how commonly used variations in fMRI data processing methods affect the distribution of activation in anatomically defined medial temporal lobe regions of interest (ROIs) during a complex scene-encoding task. ROIs were drawn on an MRI anatomic template formed from 3D SPGR scans of eight subjects combined in Talairach space. Separate ROIs were drawn for the posterior and anterior hippocampal formation, parahippocampal gyrus, and entorhinal cortex. Twelve different activation maps were created for each subject by using four correlation coefficients and three cluster volumes. Friedman's two-way ANOVA by ranks was used to test the hypothesis that the distribution of activated pixels among defined anatomic ROIs varied as a function of the data processing method. By simply varying the combination of correlation coefficient and cluster volume, significantly different distributions of activation within named medial temporal lobe structures were obtained from the same fMRI datasets (P < 0.015; P < 0.001). The number of subjects studied (n = 8) is in a range commonly found in the literature yet this clearly resulted in spurious associations between processing parameter variations and activation distribution. Using data processing methods that are independent of the arbitrary selection of cutoff values for thresholding activation maps may reduce the likelihood of obtaining spurious results.

3D image-based dose planning of intracavitary brachytherapy and teletherapy of gynecological tumors: registration of cumulative dose via deformable anatomic templates

3D image-based dose planning of intracavitary brachytherapy and teletherapy of gynecological tumors: registration of cumulative dose via deformable anatomic templates

Image-based dose planning of intracavitary brachytherapy: registration of serial-imaging studies using deformable anatomic templates

Purpose: To demonstrate that high-dimensional voxel-to-voxel transformations, derived from continuum mechanics models of the underlying pelvic tissues, can be used to register computed tomography (CT) serial examinations into a single anatomic frame of reference for cumulative dose calculations. Methods and Materials: Three patients with locally advanced cervix cancer were treated with CT-compatible intracavitary (ICT) applicators. Each patient underwent five volumetric CT examinations: before initiating treatment, and immediately before and after the first and second ICT insertions, respectively. Each serial examination was rigidly registered to the patient’s first ICT examination by aligning the bony anatomy. Detailed nonrigid alignment for organs (or targets) of interest was subsequently achieved by deforming the CT exams as a viscous-fluid, described by the Navier-Stokes equation, until the coincidence with the corresponding targets on CT image was maximized. In cases where ICT insertion induced very large and topologically complex rearrangements of pelvic organs, e.g., extreme uterine canal reorientation following tandem insertion, a viscous-fluid-landmark transformation was used to produce an initial registration. Results: For all three patients, reasonable registrations for organs (or targets) of interest were achieved. Fluid-landmark initialization was required in 4 of the 11 registrations. Relative to the best rigid bony landmark alignment, the viscous-fluid registration resulted in average soft-tissue displacements from 2.8 to 28.1 mm, and improved organ coincidence from the range of 5.2% to 72.2% to the range of 90.6% to 100%. Compared to the viscous-fluid transformation, global registration of bony anatomy mismatched 5% or more of the contoured organ volumes by 15–25 mm. Conclusion: Pelvic soft-tissue structures undergo large deformations and displacements during the external-beam and multiple-ICT course of radiation therapy for locally advanced cervix cancer. These changes cannot be modeled by the conventional rigid landmark transformation method. In the current study, we found that the deformable anatomic template registration method, based on continuum-mechanics models of deformation, successfully described these large anatomic shape changes before and after ICT. These promising modeling results indicate that realistic registration of the cumulative dose distribution to the organs (or targets) of interest for radiation therapy of cervical cancers is achievable.

Central benzodiazepine receptors in malformations of cortical development: A quantitative study.

We calculated [(11)C]flumazenil volume of distribution ([(11)C]FMZ-V(d)) after correction for partial volume effect in 10 patients with malformations of cortical development (MCDs) and partial seizures, to quantify the GABA(A)-central benzodiazepine receptor complex. Abnormal grey matter and adjacent or overlying cortex were outlined individually and added to an individualized anatomical template for correction for partial volume effect. Nine of 10 patients showed single or multiple increases or decreases in [(11)C]FMZ-V(d) in or around MCDs. Two of three patients with band heterotopia showed multiple increases in the overlying cortex. In three of four patients with subependymal nodular heterotopia, nodules had lower [(11)C]FMZ-V(d) than the overlying cortex, which was normal. Decreases in [(11)C]FMZ-V(d) were found in two of three clefts and one of six adjacent regions in one schizencephalic patient; another had normal [(11)C]FMZ-V(d) in the thickened cortex itself but increases in all adjacent regions. Binding was reduced within focal cortical dysplasia but increased in adjacent cortex. [(11)C]FMZ-V(d) was normal within one patient's polymicrogyric cortex but increased in one of six adjacent volumes of interest. The localization of abnormalities correlated with EEG and clinical data in cortical MCDs. Flumazenil binding was decreased in some MCDs with increased grey matter volume and increased in some adjacent or overlying areas of normal-appearing cortex, suggesting functional abnormalities beyond MRI- detectable structural changes.

Farm Animal Production: Changing Agriculture in a Changing Culture

Western attitudes toward animals have undergone a gradual evolution during recent centuries, driven by the scientific recognition that humans and many other species share a common anatomical template, a common phylogenetic ancestry, and certain similarities in their social and emotional lives. This evolving view has been accompanied by a heightened popular respect for animals, which has caused increasing opposition to the relatively utilitarian treatment of animals in modern farming. Western culture also tends to venerate the pastoralist image of humans caring diligently for animals, and North Americans tend to venerate the agrarian life-style of farm families living in harmony with domestic animals and the land. These positive images, which have traditionally lent legitimacy to animal agriculture, have been diminished by changes in production methods during recent decades. The resulting debate between critics and defenders of modern animal production has led to widespread confusion and concern about how animal agriculture affects animal welfare, human health, the environment, and world food security. To resolve this situation will require research to create an accurate understanding of the diverse effects of modern animal agriculture, together with measures to harmonize agricultural practices with changing public values.

Computer-assisted surgical planning. 3-D software for the PC

A potent software was developed for virtual planning in orthopedic surgery with complex spatial relationships, that runs on a standard PC with Windows 98/NT/2000. This voxel-based 3D-software creates data from tomographic images (CT, MRI, 3D-Sono, PET) in Dicom-III-format, that are visualized in near real-time as 2D-reconstructions or 3D-images. For three-dimensional analysis interactive tools, geometric rulers and an anatomic coordinate-system are available. Multiplanar osteotomies are carried out with a virtual saw. Selected segments are moved freely to mimic fracture reduction and deformity correction. Three-dimensional movement coordination is supported by problem-oriented movement features and a 3D-mouse. User defined objects in CAD-format like implants or anatomical templates can be inserted and moved. Matching of two volume data sets is possible as well as simultaneous processing of different data sets. All 3D-reconstructions can be calculated as virtual radiographs and viewed stereoscopically with LCD-shutter glasses. Export features in various data formats allow further processing of all volume data in CAD applications and rapid prototyping. An intra-operative navigation system can be integrated via an interface. This universally applicable software allows thorough three-dimensional analysis and processing of volume data sets from tomographic images and can be used in various applications through its flexible modular setup.