The Use Of A Computerized Brain Atlas In Positron Emission Tomography

Bohm, C.; Greitz, T.

doi:10.1117/12.966706

Cited by 14 publications

(23 citation statements)

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“…A parameter measuring this effect in a specific region is the recovery coefficient. The recovery coefficient for the putamen is 0.85 in PC 384-7B (Bohm et al, 1986) and close to 1.0 in PC 2048-15B. This difference in recovery coefficients is reflected in the about 10 per cent higher P/C ratios obtained with PC 2048-15B compared to PC 384-7B.…”

Section: Discussionmentioning

confidence: 55%

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PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

Nordström

Farde

Pauli

et al. 1992

Human Psychopharmacology

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Central D2-dopamine receptor occupancy determined by positron emission tomography (PET) during neuroleptic drug treatment may be a useful measure for optimal dose finding in schizophrenic patients. The clinical benefit is dependent on the reliability of such determinations. The ratio of radioactivity in the striatum to that of the cerebellum 1s widely used for calculation of D2-receptor occupancy and as an index of D2-dopamine receptor density. To test the reliability of such ratios a test-retest analysis was performed in a series of healthy subjects.The reliability was very high, both when experiments were repeated on the same day and after time intervals of months to years. A group of subjects were examined twice using PET camera systems with different resolution.The strialuni to cerebellum ratios obtained from the high-resolution PET camera system were significantly higher than ratios from the camera with lower resolution. The age effect on the striatum to cerebellum ratio was examined in 25 healthy young adults and in 18 neuroleptic-naive schizophrenic patients. A statistically significant decline was found both in the healthy controls and in the schizophrenic patients. The results do not support the view that there is a lack of age effect on the D2-dopamine receptor density in schizophrenia.

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Section: Discussionmentioning

confidence: 55%

“…The images are reconstructed on a 128 x 128 matrix with a pixel size of 2.55 mm. The recovery coefficient for the human putamen has been estimated to 0.85 (Bohm et al, 1986).…”

Section: Pet Camera Systemsmentioning

confidence: 99%

PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

Nordström

Farde

Pauli

et al. 1992

Human Psychopharmacology

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“…Because the brains of normal subjects are anatomically different, it is a prerequisite that individual rCBF images be anatomically standardized before the mean changes in rCBF of a whole experimental group of subjects can be calculated. This anatomical standardization can be performed either with landmark-based stereotactical procedures or by computerized brain atlases [Bohm et al, 1986;Evans et al, 1988;Fox et al, 1988;Friston et al, 1990;Seitz et al, 19901. It has not been examined to what extent the anatomical standardization procedures themselves change the original data, nor has it been examined how the rCBF-subtraction values are distributed in each pixel across subjects in spatially standardized pictures.…”

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confidence: 99%

Three‐dimensional analysis of clustered voxels in ¹⁵O‐butanol brain activation images

Roland

Levin

Kawashima

et al. 1993

Human Brain Mapping

118

104

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Changes in the regional cerebral blood flow (rCBF) are often used as an indicator of changes in local neuronal activity of the brain. We present here quantitative measurements with positron emission tomography (PET) of rCBF with a freely diffusible flow tracer 150-butanol in control and activation states, and a pixel-by-pixel statistical parametric analysis of the rCBF changes combined with a cluster analysis. Anatomically standardized rCBF activation data from 39 normal subjects were analyzed for the occurrence of clustered voxels. Noise data was obtained from repeat measurements of rCBF with the brain in the activated state and from simulations. The variance in test-control images was largest outside the skull, and large in soft tissue regions around the brain. It was moderate but inhomogenous in gray matter, and low and homogenous in white matter. A special picture was generated of the conformation of sampled data with a normal distribution. In the gray and white matter, the pixel values were found to conform to a normal distribution, permitting calculation of Student's t-images. In the cluster analysis, activations are detected as clusters of voxels with high t-values. The clusters in activated regions, however, were considerably larger than the full width half-maximum of spatial autocorrelation function and were easily detected. Tables of the empirical Poisson-like distributions of the number of clusters of different sizes are provided, from which P values of the significance of the occurrence of clusters of different sizes can be estimated. o 1993 wiley-Liss, inc.

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“…In [12], the shape of the cortex in slices of a human brain was digitized and stored as a brain atlas. Using various geometrical warping transforms, the shape could be adapted to different brain-sizes with reasonable accuracy.…”

Section: B Source Model and Constraintsmentioning

confidence: 99%

An Evaluation of Methods for Neuromagnetic Image Reconstruction

Jeffs

Leahy

Singh

1987

IEEE Trans. Biomed. Eng.

136

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Abstract-In this paper, we discuss several aspects of a potential new medical imaging modality for producing a quantitative three-dimensional map of neuron current densities associated with brain function. The neuromagnetic image is produced by reconstructing a current dipole field from external magnetic field measurements made with an array of superconducting quantum interference device (SQUID) [3]. These data have been used to estimate the location, orientation, and magnitude of a single current dipole in the brain which best fits the data in a least squares sense [1], [4], [5]. This approach is useful when the current field of interest is known to be localized to a single small region of the brain. Neuromagnetic imaging extends this concept to the case of multiple-current dipole sources or more complex distributed current fields which would exist when separated regions of the brain are involved in a response, or during higher brain functions. In these cases, the single-dipole model is a poor match [5], [6] and we are motivated to treat the problem as one of image reconstruction. Our approach then emphasizes solutions to the inverse problem (current field from magnetic measurements) using image reconstruction algorithms and techniques which one might encounter in computed tomography or other medical imaging applications.Neuromagnetic imaging on a single reconstruction plane in the brain was first demonstrated by Singh et al. [7]. Their approach used discrete samples of the evoked magnetic field to reconstruct a current field modeled as discrete current dipole cells all lying in a single plane with either one-or two-constrained dipole orientations. The depth of this single plane was adjusted for best fit with the measured data. We propose an extension to this model which will include three-dimensional reconstructed images and multiple-dipole orientations. This allows the estimation of dipole distributions in depth as well as lateral position and orientation.The paper is organized as follows. In Section II, we introduce the basic physical model we will use for NMI and develop the mathematical formulation of this model. We then discuss possible constraints on the solution and how these may be included in the formulation. In Section III, the fundamental limits on image resolution due to background noise, the SQUID response, and the ill-conditioned nature of the system matrix are discussed. In Section IV, we present several algorithms which can be applied to the NMI reconstruction problem and evaluate their effectiveness. Results of computer model evaluation of these algorithms are also included.

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The Use Of A Computerized Brain Atlas In Positron Emission Tomography

Cited by 14 publications

References 0 publications

PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

Three‐dimensional analysis of clustered voxels in ¹⁵O‐butanol brain activation images

An Evaluation of Methods for Neuromagnetic Image Reconstruction

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The Use Of A Computerized Brain Atlas In Positron Emission Tomography

Cited by 14 publications

References 0 publications

PET analysis of central [11 C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

PET analysis of central [11 C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

Three‐dimensional analysis of clustered voxels in 15O‐butanol brain activation images

An Evaluation of Methods for Neuromagnetic Image Reconstruction

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PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

PET analysis of central [¹¹ C]raclopride binding in healthy young adults and schizophrenic patients—reliability and age effects

Three‐dimensional analysis of clustered voxels in ¹⁵O‐butanol brain activation images