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At least 325 records · Page 18Linked to original sources
PubMed1992

Neurophysiological atlas created by mapping of clinical responses elicited on electrical stimulation of the human thalamus.

By computer processing of intraoperative neurophysiological data and intraoperative X-ray films, and using a 0.5-mm-step three-dimensional atlas created by interpolation of Schaltenbrand-Bailey's atlas, a neurophysiological atlas based on clinical responses upon electrical stimulation of the subcortical structures of patients who underwent stereotactic surgery in the awake state was created. There was considerable overlap in the distribution of motor and sensory responses in the vicinity of the ventral intermediate (VIM) thalamus: however, motor responses, particularly irregular movements, tended to be confined within the VIM and ventro-oralis posterior (VOP), whereas sensory responses tended to be localized in the VIM and ventroposterolateral nuclei, with considerable extension into the ventroposterior subthalamic region. In either motor or sensory responses, no definite somatotopic pattern could be determined.

Brain Mapping↗
PubMed1993

Three-dimensional electrophysiological atlas created by computer mapping of clinical responses elicited on stimulation of human subcortical structures.

A computer-generated three-dimensional functional atlas, based on clinical responses elicited upon electrical stimulation of subcortical structures of awake patients during stereotactic functional neurosurgery is presented, which shows a characteristic distribution pattern of motor, sensory and autonomic or emotional responses, respectively. The computer system used in this study is capable of accumulation and processing of data with three-dimensional coordinates, which can be converted to an anterior commissure-posterior commissure coordinate (AC-PC) system, and displays the processed data three-dimensionally together with a three-dimensional atlas created by interpolation of the Schaltenbrand-Bailey's atlas for standard anatomical landmarks.

Anatomy, Artistic↗
PubMed1987

Microcomputer stereotactic atlas.

A stereotactic atlas to determine thalamic target sites has been incorporated into a microcomputer. Variability studies of the thalamus with mean and standard deviations of nuclear borders are depicted graphically for overlay onto operative images. Internal landmarks traditionally used to reference target points for functional stereotaxis may be determined by conventional ventriculography or derived from magnetic resonance scans. Modeling of polyline vertices established from gray scale contour mapping and atlas reconstructions further enhance the spatial understanding of relationships to midline structures. Computer integration of anatomic reference points, graphically depicted images and stereotactic atlas data into head frame coordinates can be accomplished. This method is consistent with established stereotactic techniques and allows the visual conceptualization of imaged and graphic data for functional stereotaxis.

Brain↗
PubMed1985

Methodology and clinical experience with computed tomography and a computer-resident stereotactic atlas.

We have developed a computer-resident stereotactic atlas of the human brain that quantitatively defines subcortical structures within anatomical landmarks detected on obliquely reconstructed computed tomography (CT) slices. Horizontal stereotactic atlas sections can be stretched and contracted by polar transformation and labeled by a computer to fit within these CT scan-defined landmarks. The stereotactic coordinates of any substructure on the atlas-labeled CT slice may then be calculated by the computer and expressed in mechanical adjustments on a stereotactic surgical frame located in the operating room. We demonstrate the use of this method in the stereotactic treatment of movement disorders as an augmentation to conventional ventriculography and microelectrode recording.

Aged↗
PubMed1993

Mice homozygous for a targeted disruption of Hoxd-3 (Hox-4.1) exhibit anterior transformations of the first and second cervical vertebrae, the atlas and the axis.

Gene targeting in embryo-derived stem (ES) cells was used to generate mice with a disruption in the homeobox-containing gene Hoxd-3 (Hox-4.1). Mice homozygous for this mutation show a radically remodeled craniocervical joint. The anterior arch of the atlas is transformed to an extension of the basioccipital bone of the skull. The lateral masses of the atlas also assume a morphology more closely resembling the exoccipitals and, to a variable extent, fuse with the exoccipitals. Formation of the second cervical vertebra, the axis, is also affected. The dens and the superior facets are deleted, and the axis shows 'atlas-like' characteristics. An unexpected observation is that different parts of the same vertebra are differentially affected by the loss of Hoxd-3 function. Some parts are deleted, others are homeotically transformed to more anterior structures. These observations suggest that one role of Hox genes may be to differentially control the proliferation rates of the mesenchymal condensations that give rise to the vertebral cartilages. Within the mouse Hox complex, paralogous genes not only encode very similar proteins but also often exhibit very similar expression patterns. Therefore, it has been postulated that paralogous Hox genes would perform similar roles. Surprisingly, however, no tissues or structures are affected in common by mutations in the two paralogous genes, Hoxa-3 and Hoxd-3.

Animals↗
PubMed2004

Clipless hand-assisted laparoscopic total colectomy using Ligasure Atlas.

Hand-assisted laparoscopic total colectomy for ulcerative colitis has allowed less invasive operations in acute severe colitis and poor risk, and has not yet been widely applied for the reason of prolong the operating time in comparison with open surgery. We present the advantages of the use of the LigaSure Atlas vessel sealing for vascular control during laparoscopic surgery. A retrospective study was conducted to compare 15 patients who underwent hand-assisted laparoscopic total colectomy using an ultrasonic coagulator from January 1988 to September 2002 (US group) with 18 patients who were operated using LigaSure Atlas (LS group) from October 2002 to December 2003. There was no significant difference in the background factors of patients between both groups. The operating time was 225 +/- 58 min in the LS group and less than 280 +/- 105 min in the US group. Intraoperative blood loss was 91 +/- 22 ml in the LS group and less than 212 +/- 178 ml in the US group. Postoperative bleeding did not occur in the LS group, but occurred in 1 patient in the US group (6.6%) and this patient required re-operation. Postoperative seroma formation in the abdomen was found in 3 patients of the US group (20%). The procedure using LigaSure Atlas reduced the operating time, intraoperative bleeding and operator's stress in comparison with standard ultrasonic coagulation.

Adult↗
PubMed2003

Clinical field-testing of ATLAS prosthetic system for trans-femoral amputees.

The ATLAS prosthetic system was tested on 47 trans-femoral amputees in two tropical areas. Although the craftsmanship was not acceptable, 46% (16/35) were malaligned many with the foot dorsiflexed, the user compliance was good (91%, 32/35), and the satisfaction rate high (71%, 25/35). However, after 7-10 months failures occurred in 83% (29/35) mostly because of problems with the ATLAS knee mechanism. A modification was tested and 80% (12/15) had again failed at the knee after 6 (2-12) months. The ATLAS system in its current design should be abandoned for use for trans-femoral amputees.

Adolescent↗
PubMed2002

Optimal location of thalamotomy lesions for tremor associated with Parkinson disease: a probabilistic analysis based on postoperative magnetic resonance imaging and an integrated digital atlas.

OBJECT: Renewed interest in stereotactic neurosurgery for movement disorders has led to numerous reports of clinical outcomes associated with different treatment strategies. Nevertheless, there is a paucity of autopsy and imaging data that can be used to describe the optimal size and location of lesions or the location of implantable stimulators. In this study the authors correlated the clinical efficacy of stereotactic thalamotomy for tremor with precise anatomical localization by using postoperative magnetic resonance (MR) imaging and an integrated deformable digital atlas of subcortical structures. METHODS: Thirty-one lesions were created by stereotactic thalamotomy in 25 patients with tremor-dominant Parkinson disease. Lesion volume and configuration were evaluated by reviewing early postoperative MR images and were correlated with excellent, good, or fair tremor outcome categories. To allow valid comparisons of configurations of lesions with respect to cytoarchitectonic thalamic boundaries, the MR image obtained in each patient was nonlinearly deformed into a standardized MR imaging space, which included an integrated atlas of the basal ganglia and thalamus. The volume and precise location of lesions associated with different clinical outcomes were compared using nonparametric statistical methods. Probabilistic maps of lesions in each tremor outcome category were generated and compared. Statistically significant differences in lesion location between excellent and good. and excellent and fair outcome categories were demonstrated. On average, lesions associated with excellent outcomes involved thalamic areas located more posteriorly than sites affected by lesions in the other two outcome groups. Subtraction analysis revealed that lesions correlated with excellent outcomes necessarily involved the interface of the nucleus ventralis intermedius (Vim; also known as the ventral lateral posterior nucleus [VLp]) and the nucleus ventrocaudalis (Vc; also known as the ventral posterior [VP] nucleus). Differences in lesion volume among outcome groups did not achieve statistical significance. CONCLUSIONS: Anatomical evaluation of lesions within a standardized MR image-atlas integrated reference space is a useful method for determining optimal lesion localization. The results of an analysis of probabilistic maps indicates that optimal relief of tremor is associated with lesions involving the Vim (VLp) and the anterior Vc (VP).

Aged↗
PubMed2003

Localization of stimulating electrodes in patients with Parkinson disease by using a three-dimensional atlas-magnetic resonance imaging coregistration method.

OBJECT: The aim of this study was to correlate the clinical improvement in patients with Parkinson disease (PD) treated using deep brain stimulation (DBS) of the subthalamic nucleus (STN) with the precise anatomical localization of stimulating electrodes. METHODS: Localization was determined by superimposing figures from an anatomical atlas with postoperative magnetic resonance (MR) images obtained in each patient. This approach was validated by an analysis of experimental and clinical MR images of the electrode, and the development of a three-dimensional (3D) atlas-MR imaging coregistration method. The PD motor score was assessed through two contacts for each of two electrodes implanted in 10 patients: the "therapeutic contact" and the "distant contact" (that is, the next but one to the therapeutic contact). Seventeen therapeutic contacts were located within or on the border of the STN, most of which were associated with significant improvement of the four PD symptoms tested. Therapeutic contacts located in other structures (zona incerta, lenticular fasciculus, or midbrain reticular formation) were also linked to a significant positive effect. Stimulation applied through distant contacts located in the STN improved symptoms of PD, whereas that delivered through distant contacts in the remaining structures had variable effects ranging from worsening of symptoms to their improvement. CONCLUSIONS: The authors have demonstrated that 3D atlas-MR imaging coregistration is a reliable method for the precise localization of DBS electrodes on postoperative MR images. In addition, they have confirmed that although the STN is the main target during DBS treatment for PD, stimulation of surrounding regions, particularly the zona incerta or the lenticular fasciculus, can also improve symptoms of PD.

Adult↗
PubMed2006

The intracranial entrance of the atlantal segment of the vertebral artery in crania with occipitalization of the atlas.

OBJECT: An anomalous vertebral artery (VA) position can jeopardize an otherwise successful procedure, such as a posterior cranial fossa decompression for hindbrain herniation, and may increase the propensity for VA occlusion. METHODS: The authors describe the detailed anatomy of the entrance site of the VA in adult human crania in which there is occipitalization of the atlas. They found that if the atlantal posterior arch or hemiarch was fused to the occiput one should anticipate encountering an anomalous osseous pathway as the VA enters into the cranium, as evidenced by this finding in 80% of their specimens. An anomalous entry pathway was present in all but one left-sided specimen in which the left posterior hemiarch was not fused to the occiput and one right-sided specimen in which there was an unfused and rudimentary posterior arch of the atlas. CONCLUSIONS: The clinician should consider the possibility that the VA takes anomalous routes into the skull in cases in which there is occipitalization of the atlas.

Atlanto-Axial Joint↗
PubMed1999

Relationship between laminar topology and retinotopy in the rhesus lateral geniculate nucleus: results from a functional atlas.

The primary focus of this paper is the abrupt transition that occurs midway through the rhesus lateral geniculate nucleus (LGN) from six layers posteriorly (conventionally numbered 1-6, ventral to dorsal) to four layers anteriorly. At this transition, layers 4 and 6 fuse into a single layer, as do layers 3 and 5, requiring an inversion of the stacking order of the cell categories making up layers 4 and 5. To understand the topology of this transition and its relationship to geniculate retinotopy, we have created a functional atlas of a rhesus LGN that affords three-dimensional views of morphology and retinotopy at a resolution of 25 microm. The projection of the path of the transition into visual space is highly biased toward lower visual fields, intersecting the upper vertical meridian at 6.4 degrees , the horizonal meridian at 15.4 degrees, and the lower vertical meridian at 25.0 degrees. Between inclinations of -31 degrees and 55 degrees, layers 3 and 5 merge through an elongated tear in layer 4 that subsumes the optic disk gap and extends medially and laterally; elsewhere, layers 4 and 6 merge through a tear in layer 5. These tears cause substantial violations of retinotopy and laminar integrity, so the inversion of layers 4 and 5 requires that the forces establishing retinotopy and grouping by cell class be locally overcome during morphogenesis. The transition and associated tears are evaluated in the context of recent computational models of geniculate morphogenesis. We have also used the atlas to estimate the borders of the binocular (55 approximately 62 degrees) and monocular (91 approximately 97 degrees) visual fields. Files containing the atlas are made publicly available on a website.

Algorithms↗
PubMed2000

What does ATLAS really tell us about "high" dose angiotensin-converting enzyme inhibition in heart failure?

The Assessment of Treatment with Lisinopril and Survival (ATLAS) results have been widely quoted by proponents advocating the use of "high" doses of angiotensin-converting enzyme (ACE) inhibitors for the treatment of heart failure. In ATLAS, however, the relative benefits of "high" versus "low" dose ACE inhibition were small. Intermediate doses of ACE inhibitors proven effective in previous placebo-controlled trials provide benefit that appears likely to equal or exceed the benefit from "high" dose ACE inhibition. Therefore, we recommend that physicians continue to prescribe ACE inhibitors for patients with heart failure based on the target doses used in the placebo-controlled trials and not on the "high" dose target used in ATLAS.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Scatter and attenuation correction for brain SPECT using attenuation distributions inferred from a head atlas.

UNLABELLED: Sequential transmission scanning (TS)/SPECT is impractical for neurologically impaired patients who are unable to keep their heads motionless for the extended duration of the combined scans. To provide an alternative to TS, we have developed a method of inferring-attenuation distributions (IADs), from SPECT data, using a head atlas and a registration program. The validity of replacing TS with IAD was tested in 10 patients with mild dementia. METHODS: TS was conducted with each patient using a collimated 99mTc line source and fanbeam collimator; this was followed by hexamethyl propyleneamine oxime-SPECT. IAD was derived by deformably registering the brain component of a digital head atlas to a preliminary SPECT reconstruction and then applying the resulting spatial transformation to the full head atlas. SPECT data were reconstructed with scatter and attenuation correction. Relative regional cerebral blood flow was quantified in 12 threshold-guided anatomic regions of interest, with cerebellar normalization. SPECT reconstructions using IAD were compared with those using TS (which is the "gold standard") in terms of these regions of interest. RESULTS: When we compared all regions of interest across the population, the correlation between IAD-guided and TS-guided SPECT scans was 0.92 (P < 0.0001), whereas the mean absolute difference between the scans was 7.5%. On average, IAD resulted in slight underestimation of relative regional cerebral blood flow; however, this underestimation was statistically significant for only the left frontal and left central sulcus regions (P = 0.001 and 0.002, respectively). Error analysis indicated that approximately 10.0% of the total error was caused by IAD scatter correction, 36.6% was caused by IAD attenuation correction, 27.0% was caused by discrepancies in region-of-interest demarcation from quantitative errors in IAD-guided reconstructions, and 26.5% was caused by patient motion throughout the imaging procedure. CONCLUSION: SPECT reconstructions guided by IAD are sufficiently accurate to identify regional cerebral blood flow deficits of 10%, which are typical in moderate and advanced dementia.

Brain↗
PubMed2000

Sleep atlas and multimedia database.

The ENN sleep atlas and database was set up on a dedicated server connected to the internet thus providing all services such as WWW, ftp and telnet access. The database serves as a platform to promote the goals of the European Neurological Network, to exchange patient cases for second opinion between experts and to create a case-oriented multimedia sleep atlas with descriptive text, images and video-clips of all known sleep disorders. The sleep atlas consists of a small public and a large private part for members of the consortium. 20 patient cases were collected and presented with educational information similar to published case reports. Case reports are complemented with images, video-clips and biosignal recordings. A Java based viewer for biosignals provided in EDF format was installed in order to move free within the sleep recordings without the need to download the full recording on the client.

CD-ROM↗
PubMed2001

[A multimedia atlas of skin pathology].

We prepared a digital atlas of non-tumourous skin pathology. Currently, the available digital atlases can go beyond the scope of written publications, especially with regards to ease of access, speed of preparation, updating information, fair price and unlimited capacity. This atlas can be used as a diagnostic aid, as well as for postgraduate and pregraduate teaching.

Databases, Factual↗
PubMed2003

Atlas of pesticide concentrations in Dutch surface waters: a pilot study.

A pilot study was conducted to explore the potential for geographically mapping concentrations of individual pesticides in Dutch surface waters and compiling these maps into a National Pesticide Atlas. This atlas could be used for various purposes: 1) To see where specific pesticides are monitored, observed and find out whether these are problematical. 2) To explore the relationship between environmental pesticide levels and land use, using the results as feedback to improve national pesticide admission procedures (post-registration review) 3) To review the quality of the present Dutch pesticide monitoring system. For the study we used measured data for the years 1997 and 1998, preparing maps for six illustrative pesticides. The data are presented on a grid scale of 5x5 km2. Pesticide concentrations are compared with three standards: the EU drinking water standard, the maximum tolerable risk (MTR) level and the admission standard set by the Dutch Pesticide Admission Board (CTB). The results show that all these pesticides can be satisfactorily mapped at the national level and that for most of the compounds investigated a useful relationship can be established between environmental concentration and land use. The maps also serve to show up gaps in the present pesticide monitoring system. The study yielded several new insights, among them that standards were found to be exceeded in areas and at times of the year not anticipated on the basis of land use and pesticide use statistics. As a follow-up to this pilot study a new project has been started to develop an internet version of the pesticide atlas for all measured pesticides in The Netherlands.

Environmental Monitoring↗
PubMed1977

A stereotaxic atlas of the prefrontal cortex of the cat.

A survey of existing atlases of the cat's brain has revealed a lack of coronal sections on the levels of the prefrontal cortex. On the other hand, neurophysiological and behavioral studies of this region have increased greatly in recent years. As the extent of coronal sections through the prefrontal cortex was seen to differ markedly even at separations of 1 mm, a stereotaxic atlas was made on the basis of brain sections of 16 mongrel cats. Brains were cut with the use of the paraffin or freezing method, and stained with cresyl violet, Luxol fast blue, or Kluver-Barrera's combination. Statistical methods were used to yield representative coronal outlines of sections from +20 to +30 mm anterior in 1 mm steps. A comparison with Reinoso-Suarez five coronal sections within this range showed a marked congruence between the two atlases.

Animals↗
PubMed1980

[Anatomical identification of horizontal sections on computed tomogram utilizing Schaltenbrand and Bailey's atlas of the human brain (author's transl)].

Difference in angles between horizontal section of Schaltenbrand & Bailey's atlas and horizontal section of CT based on Cantho-Meatal line is only 3.5 to 5.5 degrees. Therefore, the horizontal section of Schaltenbrand & Bailey's atlas can be utilized for analysis of the horizontal section of CT scan, because the basal ganglia are located approximately in the center of the cranial cavity. The lesions at the basal ganglia with superimposing technique utilizing the relation between horizontal section of Schaltenbrand & Bailey's atlas and analogue view of CT can be identified anatomically.

Adult↗