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Research paper thumbnail of Myofibrosarcoma (Low-Grade Myofibroblastic Sarcoma) with Intracytoplasmic Hyaline (Fibroma-like) Inclusion Bodies

Ultrastructural Pathology, 2003

Myofibrosarcoma is a controversial neoplasm composed of cells with differentiation toward myofibr... more Myofibrosarcoma is a controversial neoplasm composed of cells with differentiation toward myofibroblasts. The authors report an unusual case of myofibrosarcoma in which, in addition to the characteristic features reported, tumor cells contained intracytoplasmic hyaline (fibroma-like) inclusion bodies. A 66-year-old man complained of a painless enlarged mass in his right shoulder over the previous 6 months. The tumor recurred 2 years after operation. On histologic examination, the tumor displayed diffusely infiltrative growth with isolation of individual skeletal muscle fibers. The tumor cells were most often arranged in an intersecting (herringbone) fascicular pattern but a vaguely storiform pattern was also observed. Cellularity varied from one area to another. The cells were spindle-shaped, with ill-define pale eosinophilic cytoplasm, and a wavy or tapering nucleus with fine chromatin and small nucleoli. Intracytoplasmic hyaline inclusion bodies of variable size, often located adjacent to the nucleus, were visible in numerous spindle and stellate cells. The mitotic index was 3/10 HPF. The tumor was scored as grade 1. Immunohistochemistry revealed positive staining to muscle-specific actin, desmin and vimentin in most tumor cells. Intracytoplasmic hyaline inclusion bodies did not react specifically to any one antibody, but showed a marked ring-like immune reaction, particularly to muscle-specific actin. Electron microscopy showed tumor cells with indented nuclei and small nucleoli, abundant rough endoplasmic reticulum, micropinocytotic vesicles, and longitudinally arranged fine filaments with focal electron-dense patches and subplasmalemmal plaques. The most striking feature was the presence of large, globular or ball-like, non-membrane-bound, randomly scattered clusters of fine filament, usually adjacent to the nucleus.

Research paper thumbnail of Observations of Changing Mesoscale Circulation Patterns in the Western Gulf of Mexico

Journal of Geophysical Research, 1983

Research paper thumbnail of Trial-by-trial relationship between neural activity, oxygen consumption, and blood flow responses

Research paper thumbnail of Fast, pseudo-continuous arterial spin labeling for functional imaging using a two-coil system

Magnetic Resonance in Medicine, 2004

Research paper thumbnail of Evaluation of respiratory artifact correction techniques in multishot spiral functional mri using receiver operator characteristic analyses

Magnetic Resonance in Medicine, 1998

Navigator corrections and low-spatial frequency (LSF) over-sampling are investigated as methods f... more Navigator corrections and low-spatial frequency (LSF) over-sampling are investigated as methods for reducing respiration-related effects in multishot functional MRI. Both techniques take advantage of the smoothly varying or nearly constant phase variations linked to the respiration cycle. These techniques were tested in functional MRI studies with spiral k-space acquisitions. Receiver operator characteristic (ROC) analyses and the temporal variance averaged across the brain were used to evaluate their effectiveness. Both methods were found to increase the area under the ROC curve and to reduce the standard deviation, with the LSF oversampling method being more effective.

Research paper thumbnail of Accounting for nonlinear BOLD effects in fMRI: parameter estimates and a model for prediction in rapid event-related studies

Research paper thumbnail of Vascular dynamics and BOLD fMRI: CBF level effects and analysis considerations

Research paper thumbnail of Nonlinear Aspects of the BOLD Response in Functional MRI

Research paper thumbnail of Quantification of perfusion fMRI using a numerical model of arterial spin labeling that accounts for dynamic transit time effects

Magnetic Resonance in Medicine, 2005

A new approach to modeling the signal observed in arterial spin labeling (ASL) experiments during... more A new approach to modeling the signal observed in arterial spin labeling (ASL) experiments during changing perfusion conditions is presented in this article. The new model uses numerical methods to extend first-order kinetic principles to include the changes in arrival time of the arterial tag that occur during neuronal activation. Estimation of the perfusion function from the ASL signal using this model is also demonstrated. The estimation algorithm uses a roughness penalty as well as prior information. The approach is demonstrated in numerical simulations and human experiments. The approach presented here is particularly suitable for fast ASL acquisition schemes, such as turbo continuous ASL (Turbo-CASL), which allows subtraction pairs to be acquired in less than 3 s but is sensitive to arrival time changes. This modeling approach can also be extended to other acquisition schemes. Magn Reson Med, 2005. © 2005 Wiley-Liss, Inc.

Research paper thumbnail of Estimating test-retest reliability in functional MR imaging II: Application to motor and cognitive activation studies

Magnetic Resonance in Medicine, 1997

Functional magnetic resonance imaging (fMRI) using blood oxygenation contrast has rapidly spread ... more Functional magnetic resonance imaging (fMRI) using blood oxygenation contrast has rapidly spread into many application areas. In this paper, a new statistical model is used to evaluate the reliability of fMRI activation in a finger opposition motor paradigm for both within-session and between-session data and in a working memory paradigm for between-session data. A slice prescription procedure for between-session reproducibility is introduced. Estimates are made for the probabilities of correctly and falsely classifying voxels as active or inactive and receiver operator characteristic curves are generated. In the motor paradigm, estimated between-session reliability was found to be somewhat reduced relative to within-session reliability; however, this includes additional sources of variation and may not reflect intrinsically lower reliability. After matching false-positive classification probabilities, between-session reliability was found to be nearly identical for both motor and cognitive activation paradigms.

Research paper thumbnail of Refinación del petróleo Tipos de crudo

Research paper thumbnail of Myofibrosarcoma (Low-Grade Myofibroblastic Sarcoma) with Intracytoplasmic Hyaline (Fibroma-like) Inclusion Bodies

Ultrastructural Pathology, 2003

Myofibrosarcoma is a controversial neoplasm composed of cells with differentiation toward myofibr... more Myofibrosarcoma is a controversial neoplasm composed of cells with differentiation toward myofibroblasts. The authors report an unusual case of myofibrosarcoma in which, in addition to the characteristic features reported, tumor cells contained intracytoplasmic hyaline (fibroma-like) inclusion bodies. A 66-year-old man complained of a painless enlarged mass in his right shoulder over the previous 6 months. The tumor recurred 2 years after operation. On histologic examination, the tumor displayed diffusely infiltrative growth with isolation of individual skeletal muscle fibers. The tumor cells were most often arranged in an intersecting (herringbone) fascicular pattern but a vaguely storiform pattern was also observed. Cellularity varied from one area to another. The cells were spindle-shaped, with ill-define pale eosinophilic cytoplasm, and a wavy or tapering nucleus with fine chromatin and small nucleoli. Intracytoplasmic hyaline inclusion bodies of variable size, often located adjacent to the nucleus, were visible in numerous spindle and stellate cells. The mitotic index was 3/10 HPF. The tumor was scored as grade 1. Immunohistochemistry revealed positive staining to muscle-specific actin, desmin and vimentin in most tumor cells. Intracytoplasmic hyaline inclusion bodies did not react specifically to any one antibody, but showed a marked ring-like immune reaction, particularly to muscle-specific actin. Electron microscopy showed tumor cells with indented nuclei and small nucleoli, abundant rough endoplasmic reticulum, micropinocytotic vesicles, and longitudinally arranged fine filaments with focal electron-dense patches and subplasmalemmal plaques. The most striking feature was the presence of large, globular or ball-like, non-membrane-bound, randomly scattered clusters of fine filament, usually adjacent to the nucleus.

Research paper thumbnail of Observations of Changing Mesoscale Circulation Patterns in the Western Gulf of Mexico

Journal of Geophysical Research, 1983

Research paper thumbnail of Trial-by-trial relationship between neural activity, oxygen consumption, and blood flow responses

Research paper thumbnail of Fast, pseudo-continuous arterial spin labeling for functional imaging using a two-coil system

Magnetic Resonance in Medicine, 2004

Research paper thumbnail of Evaluation of respiratory artifact correction techniques in multishot spiral functional mri using receiver operator characteristic analyses

Magnetic Resonance in Medicine, 1998

Navigator corrections and low-spatial frequency (LSF) over-sampling are investigated as methods f... more Navigator corrections and low-spatial frequency (LSF) over-sampling are investigated as methods for reducing respiration-related effects in multishot functional MRI. Both techniques take advantage of the smoothly varying or nearly constant phase variations linked to the respiration cycle. These techniques were tested in functional MRI studies with spiral k-space acquisitions. Receiver operator characteristic (ROC) analyses and the temporal variance averaged across the brain were used to evaluate their effectiveness. Both methods were found to increase the area under the ROC curve and to reduce the standard deviation, with the LSF oversampling method being more effective.

Research paper thumbnail of Accounting for nonlinear BOLD effects in fMRI: parameter estimates and a model for prediction in rapid event-related studies

Research paper thumbnail of Vascular dynamics and BOLD fMRI: CBF level effects and analysis considerations

Research paper thumbnail of Nonlinear Aspects of the BOLD Response in Functional MRI

Research paper thumbnail of Quantification of perfusion fMRI using a numerical model of arterial spin labeling that accounts for dynamic transit time effects

Magnetic Resonance in Medicine, 2005

A new approach to modeling the signal observed in arterial spin labeling (ASL) experiments during... more A new approach to modeling the signal observed in arterial spin labeling (ASL) experiments during changing perfusion conditions is presented in this article. The new model uses numerical methods to extend first-order kinetic principles to include the changes in arrival time of the arterial tag that occur during neuronal activation. Estimation of the perfusion function from the ASL signal using this model is also demonstrated. The estimation algorithm uses a roughness penalty as well as prior information. The approach is demonstrated in numerical simulations and human experiments. The approach presented here is particularly suitable for fast ASL acquisition schemes, such as turbo continuous ASL (Turbo-CASL), which allows subtraction pairs to be acquired in less than 3 s but is sensitive to arrival time changes. This modeling approach can also be extended to other acquisition schemes. Magn Reson Med, 2005. © 2005 Wiley-Liss, Inc.

Research paper thumbnail of Estimating test-retest reliability in functional MR imaging II: Application to motor and cognitive activation studies

Magnetic Resonance in Medicine, 1997

Functional magnetic resonance imaging (fMRI) using blood oxygenation contrast has rapidly spread ... more Functional magnetic resonance imaging (fMRI) using blood oxygenation contrast has rapidly spread into many application areas. In this paper, a new statistical model is used to evaluate the reliability of fMRI activation in a finger opposition motor paradigm for both within-session and between-session data and in a working memory paradigm for between-session data. A slice prescription procedure for between-session reproducibility is introduced. Estimates are made for the probabilities of correctly and falsely classifying voxels as active or inactive and receiver operator characteristic curves are generated. In the motor paradigm, estimated between-session reliability was found to be somewhat reduced relative to within-session reliability; however, this includes additional sources of variation and may not reflect intrinsically lower reliability. After matching false-positive classification probabilities, between-session reliability was found to be nearly identical for both motor and cognitive activation paradigms.

Research paper thumbnail of Refinación del petróleo Tipos de crudo