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At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Position and growth of upper and lower tooth primordia in prenatal mouse--3D study.

The secondary palate formation in mouse has been associated with the period of fast growth of the mandible from embryonic days (ED) 13.0 to 16.0. During that time, the incisors and first molars develop from the bud to the bell stage. We investigated the position and growth of the tooth during prenatal elongation of the lower and upper jaws, and searched for the developmental stage when alignment of opposing teeth was achieved. Computer-aided 3D representations allowed us to represent the position of incisors and molars in the embryonic head from ED 13.5 to 18.0 on the basis of data obtained from histological sections. The atlas-hypophysis connection exhibited minimum change in length and orientation during the prenatal period, and thus was used as a reference line. The length of the teeth was calculated from 3D data. The upper first and second molars were longer than the lower ones. When viewed from the upper side, the upper and lower molar primordia were parallel from ED 13.5 to 15.0. During this period, the upper molars had a more lateral position than the lower ones. This situation was maintained in the anterior extremity of the first molars at later stages, while the posterior part of the upper and lower molar epithelia reached opposition in the medio-lateral direction from ED 16.0. The lower incisors exhibited an apparently backward position when compared to the upper incisors at earlier stages. However, the distance between the prospective anterior tips of the opposing incisors gradually decreased. The part of Meckel's cartilage associated with the lower dental quadrant elongated more than 3-fold from ED 13.5 to 18.0, and the lower jaw grew faster than the upper one. This difference resulted from the fast growth of the lower diastema from ED 14.0 to 18.0. The different growth speeds of the upper and lower jaws did not change the relative antero-posterior adjustment of the upper and lower molars, but contributed to achieving the opposition of the gnawing ends of the incisors.

Animals↗
PubMed2006

[Injuries to the craniocervical junction].

Injuries to the upper cervical spine (C0-C2) play a major role in surgical treatment of traumatic sequelae in the entire cervical spine. Even though the number of such operations has increased in recent years, there are no clear treatment recommendations for most types of cervical spine injuries. In view of the wide range of injury types and the correspondingly large number of treatment options, this review focuses mainly on the following types of injuries: C0 fractures, occipital condyle fractures (OCF), atlanto-occipital dislocation (AOD), atlas fractures, atlantoaxial dislocation (AAD), and axis fractures. Important aspects of the mechanisms of injury, clinical signs and symptoms, diagnostic procedures, and treatment options are discussed. Special emphasis is placed on comparatively reviewing the different treatment options discussed in the literature. A summary in table form is presented at the end of each chapter for quick reference.

Adolescent↗
PubMed1993

Quantification of central benzodiazepine receptor binding potential in the brain with 123I-iomazenil SPECT: technical and interobserver variability.

Factors contributing to the quantification of the central benzodiazepine receptor binding potential in vivo using 123I-iomazenil and single photon emission computed tomography (SPECT) were analysed in phantom studies and in volunteers. SPECT was performed with the SME810 multidetector system. The Hoffman three-dimensional brain phantom was used to investigate linearity and reproducibility of SPECT results using different 123I activity concentrations. Dynamic and multislice SPECT scans were performed in nine healthy volunteers between 0 and 270 min after injection of 110 MBq 123I-iomazenil. Displacement studies were performed in three volunteers using 1 mg flumazenil administered intravenously (i.v.) at 250 min postinjection (p.i.). Regions of interest (ROIs) over the cerebral cortex and various subcortical nuclei were either fixed areas based on a stereotaxic brain atlas, or manually drawn, based on 60% isocontour lines. Interobserver variability of the ROI data and ratios derived from those data were estimated for two independent observers. The brain phantom measurements showed linearity with respect to 123I concentration and good reproducibility. The interobserver study showed a reasonable interobserver reliability for the large fixed ROIs. The displacement study showed about 50% displacement in all ROIs. Concentrations of 123I-iomazenil in the brain can be measured reliably with the SME810. Large fixed ROIs based on a stereotaxic atlas may be used reliably for quantification. The level of 4 cm above the cantomeatal line does not provide a useful reference region with a very low central benzodiazepine receptor binding potential.

Adult↗
PubMed1984

Variability of bregma in 300 gram Long-Evans and Sprague-Dawley rats.

Bregma is used as an anatomical reference point for most freehand and some stereotaxic injections into the rat brain. The variability of bregma with respect to the intraaural line has been examined previously for rats of a wide range of weights. We examined this variability in 282-326 gram male rats of the Long-Evans and Sprague-Dawley strains. In both strains, mean bregma was less than that stated in a widely used stereotaxic atlas. Furthermore, the mean bregma of the Sprague-Dawley rats was significantly greater than that for the Long-Evans strain. The results suggest that bregma is inadequate as an anatomical reference for intraventricular injections in rats unless the volume injected is a substantial fraction of ventricular volume.

Animals↗
PubMed1984

Dermatology for the nondermatologist: a problem-oriented system.

We describe a logical and systematic approach to unknown dermatologic disease entities that utilizes a simple algorithm which, when properly applied, expeditiously narrows the differential diagnosis and provides a key to standard reference books. We find this algorithm system to be superior to the common and often frustrating exercise of leafing through the dermatologic atlas in search of a picture that matches the presenting rash.

Dermatology↗
PubMedDate not supplied

2003 William J. Stickel Bronze Award. Radiographic anatomy of the talus.

Detailed radiographic anatomy of the entire talus bone has not been previously described in the literature. We used radiopaque wire markers to identify 17 articular and nonarticular anatomical landmarks of the talus. Standard radiographic views of the foot and ankle were obtained: lateral (foot and ankle); anteroposterior, mortise, medial oblique, and lateral oblique (ankle); and dorsoplantar, medial oblique, and lateral oblique (foot). The resultant two-dimensional images are correlated to the three-dimensional anatomical specimen, and normal radiographic anatomy is described. Additionally, useful radiographic views for each anatomical landmark are identified. Composite figures of each useful view are presented as a pictorial atlas.

Awards and Prizes↗
PubMed1993

[Treatment of fractures of the upper cervical spine (C1 and C2)].

The authors provide a review of current opinions on the treatment of fractures in the region of C1 and C2. It is necessary to take the possibility of this localization of fractures into consideration in polytraumatized patients, in those unconscious, and in cases of algesia in the cervical region. A significant post in diagnostics belongs to CT examination which reveals the extent and type of fracture and the degree of dislocation. The authors refer to the classification of Aebi and Nazarian which should be accepted in spondylo-surgical practice. The authors recommend conservative therapy of atlas fractures, preferably by the use of Halo-apparatuses. The direct osteosynthesis by means of two compressible screws according to Böhler/Magerl represents the method of choice in treating dens fractures. The surgical modification utilizing a small T splint was proved competent in fractures interfering the vertebral corpus (type III). Fractures of isthmus with no dislocation are recommended to be treated conservatively by the use of Halo-fixation, in cases with dislocation (types E II, E III) they consider the method of intercorporal desis C 2/3 according to Decaulx and modified by Caspar, to be optimal. (Fig. 8, Ref. 20.).

Axis, Cervical Vertebra↗
PubMed2005

White matter fiber tracts of the human brain: three-dimensional mapping at microscopic resolution, topography and intersubject variability.

The position and extent of individual fiber tracts within the white matter of human brains can be identified in vivo using diffusion tensor imaging (DTI) and fiber tracking methods. Previous to this study, however, the lack of three-dimensional (3-D) probability maps precluded comparing the anatomical precision of MRI studies with microscopically defined fiber tracts in human postmortem brains. The present study provides 3-D registered maps of the topography, course and intersubject variability of major fiber tracts, which were identified at microscopic resolution. The analyzed tracts include the corticospinal tract, optic and acoustic radiations, fornix, cingulum, corpus callosum, superior longitudinal, superior and inferior occipito-frontal and uncinate fascicles; sources and targets of fiber tracts include the lateral and medial geniculate nuclei and mamillary bodies. Tracts and nuclei were identified in serial myelin-stained histological sections of ten postmortem brains. The sections were 3-D reconstructed and registered to a standardized stereotaxic space of an in vivo MR reference brain by means of linear and non-linear, elastic transformations. The individual fiber tracts and nuclei were superimposed in the reference space, and probability maps were generated as a quantitative measure of intersubject variability for each voxel of the stereotaxic space. This study presents the first stereotaxic atlas of the course, location and extent of fiber tracts and related nuclei based on microscopically defined localization and topographic data taken at multiple levels on each of the three orthogonal planes. The maps are useful for evaluating and identifying fiber bundles in DTI, for localizing subcortical lesions visible in anatomical MR images and for studying neuronal connectivity.

Adult↗
PubMed2002

Vertebral height, disc height, posteroanterior displacement and dens-atlas gap in the cervical spine: precision measurement protocol and normal data.

OBJECTIVE: (1) Precise measurement of vertebral height, disc height, posteroanterior displacement and dens-atlas gap from lateral radiographic views of the cervical spine. (2) Compilation of a normative database for these parameters, specifying dependence on gender and age. DESIGN: Descriptive study, based on measurements from lateral radiographic views of the cervical spine of healthy subjects. BACKGROUND: Normal data of vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap as well as their biological range of variation and potential dependence on gender and age are not available. METHODS: Based on computer-aided measurements from lateral radiographic views of the cervical spine, a new protocol determines these parameters. RESULTS: are compensated for radiographic magnification, variation in stature and the individually adopted posture of the cervical spine; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A specimen study as well as inter- and intra-observer studies quantify measurement errors.Results. Employing the new protocol, vertebral height C3-C7 and disc height C2/C3-C6/C7 are measured with relative errors of 3.9% and 5.7% respectively. Posteroanterior displacement C1/C2 to C6/C7 is measured with an error of 2.8% of mean vertebral depth and the dens-atlas gap is measured with an error of <1.8% of the depth of C2. A normal database for the dimensions of cervical vertebrae and discs as well as of the sagittal plane alignment of the vertebrae within the cervical spine is compiled from 135 lateral views of healthy adults. CONCLUSIONS: Vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap are measured with high precision. Normal data are presented for the first time. RELEVANCE: The new protocol in conjunction with the normal database enables future studies detecting or monitoring morphological effects of, for example, trauma, long-term high mechanical loading, disc degeneration, rheumatoid arthritis, fusion or other surgical interventions.

Adult↗
PubMed1994

Visual form discrimination from color or motion cues: functional anatomy by positron emission tomography.

To explore the extent to which various cortical functional pathways are involved in processing and analyzing different types of information that yield the same perceptual entity, we mapped anatomical structures in the human brain participating in the discrimination of visual forms mediated either by motion or color cues. Changes in regional cerebral blood flow were measured in 10 young male volunteers with positron emission tomography and with [15O]butanol. During the measurements, the subjects performed four visual discrimination tasks (form-from-motion, motion alone, form-from-color, and color alone discrimination). The individual regional cerebral blood flow images were standardized in shape and size with the help of a computerized brain atlas. Subtraction images were determined and averaged across data from all subjects. The resulting images were analyzed for statistically significant changes between specific and reference tasks. The discrimination of form by means of motion cues activated functional fields bilaterally in the inferior and lateral occipital gyri, in the lingual, anterior cingulate, middle frontal and orbitofrontal gyri, and in the left fusiform and right inferior temporal gyri. Form discrimination by color cues resulted in activation bilaterally in the inferior temporal, lateral occipital, and orbitofrontal gyri, the left precuneus and intraparietal sulcus, and the right precentral gyrus. The regions engaged in the two kinds of form discrimination did not overlap, demonstrating that differences in visual forms mediated by color or motion cues are processed and analyzed by disparate networks of functional fields in human cerebral cortex.

Adult↗
PubMedDate not supplied

["Tactic and technique" for keeping medical information on compact disk].

Based on experience accumulated in time of realization and publication the Atlas of Surgical Pathology, the work present the main methodologies elements used for keeping of some elements so called by "tactics" (cases, following in time) it's insist on photographic technology in medical practice with special reference to digital technology, later on being also described the elements of processing and keeping the medical information on compact disk. Finally are enunciated a series of virtual programs with surgical specific proposed for be created and maintained on-line, with the support of all interested surgeons.

Atlases as Topic↗
PubMed1997

Detection, visualization and animation of abnormal anatomic structure with a deformable probabilistic brain atlas based on random vector field transformations.

This paper describes the design, implementation and preliminary results of a technique for creating a comprehensive probabilistic atlas of the human brain based on high-dimensional vector field transformations. The goal of the atlas is to detect and quantify distributed patterns of deviation from normal anatomy, in a 3-D brain image from any given subject. The algorithm analyzes a reference population of normal scans and automatically generates color-coded probability maps of the anatomy of new subjects. Given a 3-D brain image of a new subject, the algorithm calculates a set of high-dimensional volumetric maps (with typically 384(2) x 256 x 3 approximately 10(8) degrees of freedom) elastically deforming this scan into structural correspondence with other scans, selected one by one from an anatomic image database. The family of volumetric warps thus constructed encodes statistical properties and directional biases of local anatomical variation throughout the architecture of the brain. A probability space of random transformations, based on the theory of anisotropic Gaussian random fields, is then developed to reflect the observed variability in stereotaxic space of the points whose correspondences are found by the warping algorithm. A complete system of 384(2) x 256 probability density functions is computed, yielding confidence limits in stereotaxic space for the location of every point represented in the 3-D image lattice of the new subject's brain. Color-coded probability maps are generated, densely defined throughout the anatomy of the new subject. These indicate locally the probability of each anatomic point being unusually situated, given the distributions of corresponding points in the scans of normal subjects. 3-D MRI and high-resolution cryosection volumes are analyzed from subjects with metastatic tumors and Alzheimer's disease. Gradual variations and continuous deformations of the underlying anatomy are simulated and their dynamic effects on regional probability maps are animated in video format (on the accompanying CD-ROM). Applications of the deformable probabilistic atlas include the transfer of multi-subject 3-D functional, vascular and histologic maps onto a single anatomic template, the mapping of 3-D atlases onto the scans of new subjects, and the rapid detection, quantification and mapping of local shape changes in 3-D medical images in disease and during normal or abnormal growth and development.

Anatomy, Cross-Sectional↗
PubMedDate not supplied

[Pelvic lymph node groups in computed tomography. Topographic atlas].

This atlas was prepared to facilitate the diagnosis of lymph mode enlargement in the pelvic region and to improve topographic diagnosis. Fifty computed tomographies were performed after lymphography using centimetric pelvic slices in order to select eight levels for reference. A statistical analysis was conducted to establish a diagram of the mean number of lymph nodes on the right and left side for each level. A table was established indicating the mean number and standard deviation for each group of nodes for the 8 different levels. In addition, a control slice (chosen among 50) accounts for the morphology of the iliac vessels, of the lymph nodes and psoas muscle most frequently encountered at each level. The distribution of the groups of nodes shows why interpretation can be difficult, particularly at vessel bifucations and confluents. Precise morphology based on effective opacification, especially in the pelvic area, is required for positive and especially topographic diagnosis. Finally, the description of the medial border of the psoas muscle and its close relations with certain groups of lymph nodes can cause some problems because of the similar densities. The atlas is of great help here.

Anatomy, Regional↗
PubMed1996

A stereotaxic atlas of the basal ganglia in macaques.

Maps of the striatum, pallidum and subthalamic nucleus were established in two macaque species (Macaca mulatta and Macaca fascicularis) in stereotaxic coordinates. The cartographic method relied on the use of intracerebral, ventricular landmarks (CA: anterior commissure and CP: posterior commissure). The basal ganglia outlines, first drawn in transverse sections perpendicular to the CA-CP plane, were reconstructed on the horizontal and midsagittal planes. Maps from several individuals were superimposed and statistical variations studied. The results confirm that the length between the two CA and CP points is statistically greater (7%) in the Macaca mulatta than Macaca fascicularis but reveal considerable inter-individual differences. The closer a given nucleus is from a ventricular reference point, the more stable its outline. Superimpositions led to a statistical determination of the stereotaxic coordinates required to reach a given target center. Comparison of the lateralities with those measured in six previously published atlases indicates that the brain mapped by Snider and Lee [17] is the smallest and that mapped by Olszewski [8] is the largest.

Animals↗
PubMed1977

Searching for names in two city street maps.

Two experiments investigated the speed with which names could be found on maps from two London street atlases. Differences in grid referencing between the maps accounted for large differences in search times. However, small statistically significant differences were still present when grid references were not being used, and these cannot be explained in terms of map scale, nor in terms of greater familiarity with the faster map. Several design differences could have contributed to this effect and it is likely that the use of lower case type on the faster map was an important factor. Implications for the map designer are discussed.

Journal Article↗