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At least 19 recordsLinked to original sources

PubMed2003

The Cerefy Neuroradiology Atlas: a Talairach-Tournoux atlas-based tool for analysis of neuroimages available over the internet.

The article introduces an atlas-assisted method and a tool called the Cerefy Neuroradiology Atlas (CNA), available over the Internet for neuroradiology and human brain mapping. The CNA contains an enhanced, extended, and fully segmented and labeled electronic version of the Talairach-Tournoux brain atlas, including parcelated gyri and Brodmann's areas. To our best knowledge, this is the first online, publicly available application with the Talairach-Tournoux atlas. The process of atlas-assisted neuroimage analysis is done in five steps: image data loading, Talairach landmark setting, atlas normalization, image data exploration and analysis, and result saving. Neuroimage analysis is supported by a near-real-time, atlas-to-data warping based on the Talairach transformation. The CNA runs on multiple platforms; is able to process simultaneously multiple anatomical and functional data sets; and provides functions for a rapid atlas-to-data registration, interactive structure labeling and annotating, and mensuration. It is also empowered with several unique features, including interactive atlas warping facilitating fine tuning of atlas-to-data fit, navigation on the triplanar formed by the image data and the atlas, multiple-images-in-one display with interactive atlas-anatomy-function blending, multiple label display, and saving of labeled and annotated image data. The CNA is useful for fast atlas-assisted analysis of neuroimage data sets. It increases accuracy and reduces time in localization analysis of activation regions; facilitates to communicate the information on the interpreted scans from the neuroradiologist to other clinicians and medical students; increases the neuroradiologist's confidence in terms of anatomy and spatial relationships; and serves as a user-friendly, public domain tool for neuroeducation. At present, more than 700 users from five continents have subscribed to the CNA.

Atlases as Topic↗

PubMed1997

Multiple brain atlas database and atlas-based neuroimaging system.

For the purpose of developing multiple, complementary, fully labeled electronic brain atlases and an atlas-based neuroimaging system for analysis, quantification, and real-time manipulation of cerebral structures in two and three dimensions, we have digitized, enhanced, segmented, and labeled the following print brain atlases: Co-Planar Stereotaxic Atlas of the Human Brain by Talairach and Tournoux, Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren, Referentially Oriented Cerebral MRI Anatomy by Talairach and Tournoux, and Atlas of the Cerebral Sulci by Ono, Kubik, and Abernathey. Three-dimensional extensions of these atlases have been developed as well. All two- and three-dimensional atlases are mutually preregistered and may be interactively registered with an actual patient's data. An atlas-based neuroimaging system has been developed that provides support for reformatting, registration, visualization, navigation, image processing, and quantification of clinical data. The anatomical index contains about 1,000 structures and over 400 sulcal patterns. Several new applications of the brain atlas database also have been developed, supported by various technologies such as virtual reality, the Internet, and electronic publishing. Fusion of information from multiple atlases assists the user in comprehensively understanding brain structures and identifying and quantifying anatomical regions in clinical data. The multiple brain atlas database and atlas-based neuroimaging system have substantial potential impact in stereotactic neurosurgery and radiotherapy by assisting in visualization and real-time manipulation in three dimensions of anatomical structures, in quantitative neuroradiology by allowing interactive analysis of clinical data, in three-dimensional neuroeducation, and in brain function studies.

Anatomy, Artistic↗

PubMed2004

Evaluation of atlas selection strategies for atlas-based image segmentation with application to confocal microscopy images of bee brains.

This paper evaluates strategies for atlas selection in atlas-based segmentation of three-dimensional biomedical images. Segmentation by intensity-based nonrigid registration to atlas images is applied to confocal microscopy images acquired from the brains of 20 bees. This paper evaluates and compares four different approaches for atlas image selection: registration to an individual atlas image (IND), registration to an average-shape atlas image (AVG), registration to the most similar image from a database of individual atlas images (SIM), and registration to all images from a database of individual atlas images with subsequent multi-classifier decision fusion (MUL). The MUL strategy is a novel application of multi-classifier techniques, which are common in pattern recognition, to atlas-based segmentation. For each atlas selection strategy, the segmentation performance of the algorithm was quantified by the similarity index (SI) between the automatic segmentation result and a manually generated gold standard. The best segmentation accuracy was achieved using the MUL paradigm, which resulted in a mean similarity index value between manual and automatic segmentation of 0.86 (AVG, 0.84; SIM, 0.82; IND, 0.81). The superiority of the MUL strategy over the other three methods is statistically significant (two-sided paired t test, P < 0.001). Both the MUL and AVG strategies performed better than the best possible SIM and IND strategies with optimal a posteriori atlas selection (mean similarity index for optimal SIM, 0.83; for optimal IND, 0.81). Our findings show that atlas selection is an important issue in atlas-based segmentation and that, in particular, multi-classifier techniques can substantially increase the segmentation accuracy.

Algorithms↗

PubMed1999

A brainstem stereotactic atlas in a three-dimensional magnetic resonance imaging navigation system: first experiences with atlas-to-patient registration.

OBJECT: The authors describe a computer-resident digital representation of a stereotactic atlas of the human brainstem, its semiautomated registration to sagittal fast low-angle shot three-dimensional (3-D) magnetic resonance (MR) imaging data sets in 27 healthy volunteers and 24 neurosurgical patients, and an analysis of the subsequent transforms needed to refine the initial registration. METHODS: Contour drawings from the atlas, which offer the 70th percentile of variation of anatomical structures, were interpolated into an isotropic 3-D representation. Initial atlas-to-patient registration was based on the fastigium/ventricular floor plane reference system. The quality of the fit was evaluated using superimposition of the atlas and MR images. If necessary, the atlas was tailored to the individual anatomy by using additional transforms. On average, the atlas had to be stretched by 2 to 6% in the three directions of space. Scale factors varied over a broad range from -8 to +19% and the benefit of visual interactive control of the atlas-to-patient registration was evident. Analysis of distances within the pons measured in the midsagittal MR imaging slices and the required scale factors revealed significant correlations that may be used to reduce the amount of user interaction in the coregistration substantially. In 70.6% of the cases, the atlas had to be shifted in a cranial direction along the brainstem axis (in 25.5% of cases 3-4 mm, in 45.1% of cases 1-2 mm). This was due to a more caudal position of the fastigium cerebelli on the MR images compared with the atlas. CONCLUSIONS: This observation, in conjunction with the variability of the height of the fourth ventricle in our MR imaging data (range 6.1-15.2 mm, mean 10.1 mm, standard deviation 1.8 mm) calls into question the role of the fastigium cerebelli as an anatomical landmark for localization within the brainstem.

Anatomy, Artistic↗

PubMed1995

The Atlas of Health and Working Conditions by Occupation. 2. A comparison with the "Atlas of Health and Working Conditions in the Construction Industry".

The results of the general Atlas of Health and Working Conditions by Occupation were compared with the results of the Atlas of Health and Working Conditions in the Construction Industry. Both are based on questionnaire data from periodical occupational health surveys [POHSs]. The scores on most of the items showed considerable differences between the two atlases, partly due to differences in the regional origin of the data. Therefore, direct comparisons between the atlases are biased by regional differences. To study the reliability and the generalizability of the results of both atlases, similarities between the data files with respect to occupations in the construction industry were studied. Most of the items on working conditions, especially those with a widespread distribution, showed a close resemblance between the data files in terms of the relative position of an occupation compared to other occupations in the construction industry. The items on health showed less resemblance, except for the items on musculoskeletal complaints, which showed results similar to those of the work items. These results indicate the reliability and generalizability of the judgements based on both atlases outside the regions of origin, as far as items with a widespread distribution are concerned. Therefore, we recommend the aggregation of POHS data on a national scale, taking regional differences into account. In that way, a greater number of occupations will be described and the reliability of the results will be enhanced.

Adult↗

PubMed1997

An atlas vertebra with a centrum? A case report of an abnormal atlas and axis.

This case report represents the finding of an abnormal atlas vertebra during dissection of 34 cadavers. The case which we describe appeared to have an atlas with a mass at a position similar to that of a centrum. This mass may have been a developmental abnormality of the centrum of the atlas or may have represented a congenital abnormality, known as the os odontoideum. Alternatively the abnormality may have been due to non-union of an odontoid fracture, with subsequent fusion to the atlas. The case report will discuss which of these three alternatives is more probable, and the embryology and phylogenesis of the atlas and axis, leading us to believe in a congenital hypothesis as an explanation for the malformation.

Cadaver↗

PubMed1987

Creation of a three-dimensional atlas by interpolation from Schaltenbrand-Bailey's atlas.

A 0.5-mm step atlas was interpolated from Schaltenbrand-Bailey's atlas. By serial display of the atlas with the desired rotation on a three-dimensional axis, a three-dimensional atlas was created. The newly created atlas can be used for computer-processed stereotactic data display. Any three-dimensionally located point can be displayed within 0.25 mm distance from the point, and spatial understanding of anatomical structures and stereotactic data is facilitated by the three-dimensional display.

Brain↗

PubMed2000

The Morel stereotactic atlas of the human thalamus: atlas-to-MR registration of internally consistent canonical model.

In 1997, Morel, Magnin, and Jeanmonod presented a microscopic stereotactic atlas of the human thalamus. Parcellations of thalamic nuclei did not only use cyto- and myeloarchitectonic criteria, but were additionally corroborated by staining for calcium-binding proteins, which bears functional significance. The atlas complies with the Anglosaxon nomenclature elaborated by Jones and the data were sampled in three orthogonal planes in the AC-PC reference space. We report on the generation of three-dimensional digital models of the thalamus based on the three sets of sections (sagittal, horizontal, and frontal). Spatial differences between the three anatomical specimens were evaluated using the centers of gravity of 13 selected nuclei as landmarks. Subsequent linear regression analysis yielded equations, which were used to normalize the frontal and horizontal digital models to the sagittal one. The outcome is an internally consistent Canonical Model of Morel's atlas, which minimizes the linear component of the variability between the three sectioned anatomical specimens. In addition, we demonstrate the feasibility of the atlas-to-MRI registration in conjunction with on-line visualization of the trajectory in the digital models.

Brain Mapping↗

PubMed1998

A scheme for automatically building three-dimensional morphometric anatomical atlases: application to a skull atlas.

We present a general scheme for automatically building a morphometric anatomical atlas. We detail each stage of the method, including the non-rigid registration algorithm, three-dimensional line averaging and statistical processes. We apply the method to obtain a quantitative atlas of skull crest lines. Finally, we use the resulting atlas to study a craniofacial disease; we show how we can obtain qualitative and quantitative results by contrasting a skull affected by a mandible deformation with the atlas.

Algorithms↗

PubMed1987

Injuries of the atlas and axis. A follow-up study of 85 axis and 10 atlas fractures.

In a follow-up study of ten atlas and 85 axis fractures, 12% had residual symptoms in the form of local and radiating cervical pain. The residual symptoms were interpreted as a sign of a mild demyelinating process initiated by the trauma of the medulla. At least 22% of the accidents occurred while the person was under the influence of drugs or alcohol. Therefore, a wide range of residual symptoms (progressive or nonprogressive) could be attributed in part to abuse of drugs and alcohol. A permanent measurable loss of motion occurred following injury to the atlas or axis, irrespective of the modality of treatment. Cervical fusion created the greatest loss of motion and collar immobilization the least. Skull traction and a halo-vest were intermediate in patients with loss of motion, and the degree of loss of range was essentially equal. Residual symptoms, including pain, were found in 20% of those treated with a collar, 40% of those treated with surgical methods, 5% of those treated with traction, and 5% of those treated with a Halo-vest. Residual symptoms did not correlate at all with degree of displacement of the original fracture.

Adult↗

PubMed2000

Low doses vs. high doses of the angiotensin converting-enzyme inhibitor lisinopril in chronic heart failure: a cost-effectiveness analysis based on the Assessment of Treatment with Lisinopril and Survival (ATLAS) study. The ATLAS Study Group.

OBJECTIVE: A cost-effectiveness analysis of high and low doses of the angiotensin-converting enzyme (ACE) inhibitor lisinopril in the treatment of chronic heart failure. METHODS: A cost-effectiveness analysis using data from a randomized controlled trial, ATLAS, where 3164 patients with chronic heart failure were allocated to a high-dose (daily target dose 32.5-35 mg) or low-dose strategy (daily target dose 2.5-5.0 mg) of lisinopril. Differential costs were based on resource use data collected in the trial costed using UK unit costs. Cost-effectiveness analysis related differential costs to differential life-years during a 4-year trial follow-up. RESULTS: The mean total number of hospital in-patient days per patient was 18. 5 in the high dose group and 22.5 in the low dose group. Over the whole duration of the trial, the mean (S.D.) daily dose of lisinopril in the high-dose group was 22.5 mg (15.7 mg) compared to 3.2 mg (2.5 mg) in the low-dose group. The mean difference in cost per patient was pound sterling 397 lower in the high-dose group [95% CI (high-dose-low-dose) - pound sterling 1263 to pound sterling 436]. Mean life-years per patient were 0.085 years higher in the high-dose group [95% CI (high-dose-low-dose) -0.0074 to 0.1706). Based on mean costs and life-years, high-dose therapy dominates low-dose (less costly and more effective). Allowing for uncertainty in mean costs and life-years, the probability of high-dose therapy being less costly than low dose was 82%. If a decision maker is willing to pay at least pound sterling 3600 per life-year gained, the probability of high-dose being more cost-effective was 92%. CONCLUSIONS: The ATLAS Study showed that the treatment of heart failure with high-doses of lisinopril has a high probability of being more cost-effective than low-dose therapy.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2002

Regional size differences in four commonly used cephalometric atlases: the Ann Arbor, Cleveland (Bolton), London (UK), and Philadelphia atlases compared.

OBJECTIVE: To explore regional influence on size in roentgenocephalometric atlases. DESIGN: Comparisons of the size of 10 linear distances in four atlases from geographically different regions, i.e. Ann Arbor Michigan, Cleveland Ohio, Philadelphia Pennsylvania and London, UK. DISTANCES COMPARED: anterior cranial base length (S-N), posterior cranial base length (S-Ba), total face height (N-Me), upper face height (N-ANS), lower face height (ANS-Me), mandibular diagonal (Ar-Gn), corpus length (Go-Pg), ramus height (Ar-Go), maxillary length (SNP-SNA), posterior face height (S-Go). RESULTS: Correction for enlargement appeared to be a necessity before distances could be compared. After correction for enlargement, the anterior cranial base was longest in Ann Arbor, lower face height smallest in Cleveland (Bolton standards) and the maxilla was shortest in Philadelphia. CONCLUSION: Regional size variance in cephalometric data cannot be ignored.

Adolescent↗

PubMed1964