OBJECTIVE: The goal of this study was to determine the consistency of human reviewer spike detect... more OBJECTIVE: The goal of this study was to determine the consistency of human reviewer spike detection and then develop a computer algorithm to make the intracranial spike detection process more objective and reliable. METHODS: Three human reviewers marked interictal spikes on samples of intracranial EEGs from 10 patients. The sensitivity, precision and agreement in channel ranking by activity were calculated between reviewers.
Abstract In medical domains with low tolerance for invalid predictions, classification confidence... more Abstract In medical domains with low tolerance for invalid predictions, classification confidence is highly important and traditional performance measures such as overall accuracy cannot provide adequate insight into classifications reliability. In this paper, a confident-prediction rate (CPR) which measures the upper limit of confident predictions has been proposed based on receiver operating characteristic (ROC) curves. It has been shown that heterogeneous ensemble of classifiers improves this measure.
Abstract Texture analysis is an important issue in image processing with many applications includ... more Abstract Texture analysis is an important issue in image processing with many applications including medical imaging, remote sensing, content-based image retrieval, and document segmentation. Over the last three decades, texture analysis has been widely studied and many techniques have been proposed in the literature. Ideally, texture analysis should be invariant to rotation. However, many of the proposed techniques assume that texture has the same orientation, which is not always the case.
Abstract We develop and evaluate a variational Bayesian expectation maximization (VBEM) method fo... more Abstract We develop and evaluate a variational Bayesian expectation maximization (VBEM) method for model inversion of our multi-area extended neural mass model (MEN) using EEG/MEG data. Parameters of MEN have suitable prior distributions that enable us to use properties of a conjugate-exponential model in implementing VBEM.
Purpose. Contradictory scalp electroencephalographic (sEEG) and discordant imaging features are c... more Purpose. Contradictory scalp electroencephalographic (sEEG) and discordant imaging features are common in temporal lobe epilepsy (TLE). We assessed the relative importance of sEEG features and their relation to quantitative magnetic resonance (MR) imaging measures in regard to surgical outcome. Methods and materials. Patients with a putative TLE underwent extraoperative electrocorticography (eECoG) with bitemporal subdural electrodes for clarification of the ictogenic source.
ABSTRACT This paper improves the Lateralization (identification of the epileptogenic hippocampus)... more ABSTRACT This paper improves the Lateralization (identification of the epileptogenic hippocampus) accuracy in Mesial Temporal Lobe Epilepsy (mTLE). In patients with this kind of epilepsy, usually one of the brain's hippocampi is the focus of the epileptic seizures, and resection of the seizure focus is the ultimate treatment to control or reduce the seizures.
Abstract The hippocampus has become the focus of research in several neurodegenerative disorders.... more Abstract The hippocampus has become the focus of research in several neurodegenerative disorders. Automatic segmentation of this structure from magnetic resonance (MR) imaging scans of the brain facilitates this work. Segmentation techniques must be evaluated using a dataset of MR images with accurate hippocampal outlines generated manually. Manual segmentation is not a trivial task.
This paper presents a study of the texture information of high-resolution FLAIR images of the bra... more This paper presents a study of the texture information of high-resolution FLAIR images of the brain with the aim of determining the abnormality and consequently the candidacy of the hippocampus for temporal lobe epilepsy (TLE) surgery. Intensity and volume features of the hippocampus from FLAIR images of the brain have been previously shown to be useful in detecting the abnormal hippocampus in TLE. However, the small size of the hippocampus may limit the texture information.
Background: Multiple chronic rhinosinusitis (CRS) staging systems have been developed in an attem... more Background: Multiple chronic rhinosinusitis (CRS) staging systems have been developed in an attempt to correlate symptoms with radiological imaging results. Currently, no perfect system exists. We sought to analyze the maxillary sinus (MS) using three-dimensional volumetric measurements and advanced high-resolution CT imaging. Methods: We reviewed MS CT scans from 50 control subjects and 50 subjects with documented CRS involving at least one MS.
With the ever increasing data, there is a greater need for analyzing and extracting useful and me... more With the ever increasing data, there is a greater need for analyzing and extracting useful and meaningful information out of it. The amount of research being conducted in extracting this information is commendable. From clustering to bi and multi clustering, there are a lot of different algorithms proposed to analyze and discover the hidden patterns in data, in every which way possible.
Background: Determining malignancy of prostate pathological samples is important for treatment pl... more Background: Determining malignancy of prostate pathological samples is important for treatment planning of prostate cancer. Traditionally, this is performed by expert pathologists who evaluate the structure of prostate glands in the biopsy samples. However, this is a subjective task due to inter-and intra-observer differences among pathologists. Also, it is time-consuming and difficult to some extent. Therefore, automatic determination of malignancy of prostate pathological samples is of interest.
Standard magnetic resonance (MR) imaging analysis in several cases of mesial temporal lobe epilep... more Standard magnetic resonance (MR) imaging analysis in several cases of mesial temporal lobe epilepsy (mTLE) either fail to show an identifiable hippocampal asymmetry or provide only subtle distinguishing features that remain inconclusive. A retrospective analysis of hippocampal fluid-attenuated inversion recovery (FLAIR) MR images was performed in cases of mTLE addressing, particularly, the mean and standard deviation of the signal and its texture.
The hippocampus has been the primary region of interest in the preoperative imaging investigation... more The hippocampus has been the primary region of interest in the preoperative imaging investigations of mesial temporal lobe epilepsy (mTLE). Hippocampal imaging and electroencephalographic features may be sufficient in several cases to declare the epileptogenic focus. In particular, hippocampal atrophy, as appreciated on T1-weighted (T1W) magnetic resonance (MR) images, may suggest a mesial temporal sclerosis.
Diffusion tensor magnetic resonance imaging (DTMRI) is a non-invasive tool for the investigation ... more Diffusion tensor magnetic resonance imaging (DTMRI) is a non-invasive tool for the investigation of white matter structure within the brain. However, the traditional tensor model is unable to characterize anisotropies of orders higher than two in heterogeneous areas containing more than one fiber population. To resolve this issue, high angular resolution diffusion imaging (HARDI) with a large number of diffusion encoding gradients is used along with reconstruction methods such as Q-ball.
Multi-parametric MRI analysis of the ischemic lesions of stroke patients demonstrates inhomogenei... more Multi-parametric MRI analysis of the ischemic lesions of stroke patients demonstrates inhomogeneities in the degree of ischemic injury and recovery potential [1]. Experimental and clinical studies indicate that the likelihood for progression to infarction in the penumbra of physiologically impaired but potentially salvageable tissue surrounding the central core of focal cerebral ischemia is the most important factor in evaluating treatment efficacy [2].
abstract Localization of epileptogenic zones in extratemporal epilepsy is a challenging problem. ... more abstract Localization of epileptogenic zones in extratemporal epilepsy is a challenging problem. We speculate that using all modalities of data in an optimal way can facilitate the localization of these zones. In this paper, we propose the following steps to transfer all modalities of data in a single reference coordinate system: 1) Segmentation of subdural and depth electrodes, and cortical surface. 2) Building 3D models of the segmented objects.
Objective: Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be... more Objective: Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be implicated in a variety of neuronal processes, including cell growth, resilience to noxious stimuli and synaptic plasticity. A Val to Met substitution at codon 66 in the BDNF protein has been associated with a variety of neuropsychiatric conditions. The ApoE4 allele is considered a risk factor for late-onset Alzheimer's disease, but its effects on young adults are less clear.
Abstract Several technologies for characterizing genes and proteins from humans and other organis... more Abstract Several technologies for characterizing genes and proteins from humans and other organisms use yeast growth or color development as read outs. The yeast two-hybrid assay, for example, detects protein-protein interactions by measuring the growth of yeast on a specific solid medium, or the ability of the yeast to change color when grown on a medium containing a chromogenic substrate.
This study assesses the utility of compartmental analysis of SPECT data in lateralizing ictal ons... more This study assesses the utility of compartmental analysis of SPECT data in lateralizing ictal onset in cases of a putative mesial temporal lobe epilepsy (mTLE). An institutional archival review provided 46 patients (18M, 28F) operated for a putative mTLE who achieved an Engel class Ia postoperative outcome. This established the standard to assure a true ictal origin.
ABSTRACT This paper presents a study on the SPECT images of the brain with the aim of determining... more ABSTRACT This paper presents a study on the SPECT images of the brain with the aim of determining the hippocampus abnormality and consequently applying timely treatment. Intensity and volume features of the hippocampus from brain MRI have been shown to be useful in detecting the abnormal hippocampus in TLE. In this study, we evaluate the intensity information of the SPECT images of the brain for the purpose of early detection of abnormal hippocampus, before the brain tissue is damaged and MRI features change.
OBJECTIVE: The goal of this study was to determine the consistency of human reviewer spike detect... more OBJECTIVE: The goal of this study was to determine the consistency of human reviewer spike detection and then develop a computer algorithm to make the intracranial spike detection process more objective and reliable. METHODS: Three human reviewers marked interictal spikes on samples of intracranial EEGs from 10 patients. The sensitivity, precision and agreement in channel ranking by activity were calculated between reviewers.
Abstract In medical domains with low tolerance for invalid predictions, classification confidence... more Abstract In medical domains with low tolerance for invalid predictions, classification confidence is highly important and traditional performance measures such as overall accuracy cannot provide adequate insight into classifications reliability. In this paper, a confident-prediction rate (CPR) which measures the upper limit of confident predictions has been proposed based on receiver operating characteristic (ROC) curves. It has been shown that heterogeneous ensemble of classifiers improves this measure.
Abstract Texture analysis is an important issue in image processing with many applications includ... more Abstract Texture analysis is an important issue in image processing with many applications including medical imaging, remote sensing, content-based image retrieval, and document segmentation. Over the last three decades, texture analysis has been widely studied and many techniques have been proposed in the literature. Ideally, texture analysis should be invariant to rotation. However, many of the proposed techniques assume that texture has the same orientation, which is not always the case.
Abstract We develop and evaluate a variational Bayesian expectation maximization (VBEM) method fo... more Abstract We develop and evaluate a variational Bayesian expectation maximization (VBEM) method for model inversion of our multi-area extended neural mass model (MEN) using EEG/MEG data. Parameters of MEN have suitable prior distributions that enable us to use properties of a conjugate-exponential model in implementing VBEM.
Purpose. Contradictory scalp electroencephalographic (sEEG) and discordant imaging features are c... more Purpose. Contradictory scalp electroencephalographic (sEEG) and discordant imaging features are common in temporal lobe epilepsy (TLE). We assessed the relative importance of sEEG features and their relation to quantitative magnetic resonance (MR) imaging measures in regard to surgical outcome. Methods and materials. Patients with a putative TLE underwent extraoperative electrocorticography (eECoG) with bitemporal subdural electrodes for clarification of the ictogenic source.
ABSTRACT This paper improves the Lateralization (identification of the epileptogenic hippocampus)... more ABSTRACT This paper improves the Lateralization (identification of the epileptogenic hippocampus) accuracy in Mesial Temporal Lobe Epilepsy (mTLE). In patients with this kind of epilepsy, usually one of the brain's hippocampi is the focus of the epileptic seizures, and resection of the seizure focus is the ultimate treatment to control or reduce the seizures.
Abstract The hippocampus has become the focus of research in several neurodegenerative disorders.... more Abstract The hippocampus has become the focus of research in several neurodegenerative disorders. Automatic segmentation of this structure from magnetic resonance (MR) imaging scans of the brain facilitates this work. Segmentation techniques must be evaluated using a dataset of MR images with accurate hippocampal outlines generated manually. Manual segmentation is not a trivial task.
This paper presents a study of the texture information of high-resolution FLAIR images of the bra... more This paper presents a study of the texture information of high-resolution FLAIR images of the brain with the aim of determining the abnormality and consequently the candidacy of the hippocampus for temporal lobe epilepsy (TLE) surgery. Intensity and volume features of the hippocampus from FLAIR images of the brain have been previously shown to be useful in detecting the abnormal hippocampus in TLE. However, the small size of the hippocampus may limit the texture information.
Background: Multiple chronic rhinosinusitis (CRS) staging systems have been developed in an attem... more Background: Multiple chronic rhinosinusitis (CRS) staging systems have been developed in an attempt to correlate symptoms with radiological imaging results. Currently, no perfect system exists. We sought to analyze the maxillary sinus (MS) using three-dimensional volumetric measurements and advanced high-resolution CT imaging. Methods: We reviewed MS CT scans from 50 control subjects and 50 subjects with documented CRS involving at least one MS.
With the ever increasing data, there is a greater need for analyzing and extracting useful and me... more With the ever increasing data, there is a greater need for analyzing and extracting useful and meaningful information out of it. The amount of research being conducted in extracting this information is commendable. From clustering to bi and multi clustering, there are a lot of different algorithms proposed to analyze and discover the hidden patterns in data, in every which way possible.
Background: Determining malignancy of prostate pathological samples is important for treatment pl... more Background: Determining malignancy of prostate pathological samples is important for treatment planning of prostate cancer. Traditionally, this is performed by expert pathologists who evaluate the structure of prostate glands in the biopsy samples. However, this is a subjective task due to inter-and intra-observer differences among pathologists. Also, it is time-consuming and difficult to some extent. Therefore, automatic determination of malignancy of prostate pathological samples is of interest.
Standard magnetic resonance (MR) imaging analysis in several cases of mesial temporal lobe epilep... more Standard magnetic resonance (MR) imaging analysis in several cases of mesial temporal lobe epilepsy (mTLE) either fail to show an identifiable hippocampal asymmetry or provide only subtle distinguishing features that remain inconclusive. A retrospective analysis of hippocampal fluid-attenuated inversion recovery (FLAIR) MR images was performed in cases of mTLE addressing, particularly, the mean and standard deviation of the signal and its texture.
The hippocampus has been the primary region of interest in the preoperative imaging investigation... more The hippocampus has been the primary region of interest in the preoperative imaging investigations of mesial temporal lobe epilepsy (mTLE). Hippocampal imaging and electroencephalographic features may be sufficient in several cases to declare the epileptogenic focus. In particular, hippocampal atrophy, as appreciated on T1-weighted (T1W) magnetic resonance (MR) images, may suggest a mesial temporal sclerosis.
Diffusion tensor magnetic resonance imaging (DTMRI) is a non-invasive tool for the investigation ... more Diffusion tensor magnetic resonance imaging (DTMRI) is a non-invasive tool for the investigation of white matter structure within the brain. However, the traditional tensor model is unable to characterize anisotropies of orders higher than two in heterogeneous areas containing more than one fiber population. To resolve this issue, high angular resolution diffusion imaging (HARDI) with a large number of diffusion encoding gradients is used along with reconstruction methods such as Q-ball.
Multi-parametric MRI analysis of the ischemic lesions of stroke patients demonstrates inhomogenei... more Multi-parametric MRI analysis of the ischemic lesions of stroke patients demonstrates inhomogeneities in the degree of ischemic injury and recovery potential [1]. Experimental and clinical studies indicate that the likelihood for progression to infarction in the penumbra of physiologically impaired but potentially salvageable tissue surrounding the central core of focal cerebral ischemia is the most important factor in evaluating treatment efficacy [2].
abstract Localization of epileptogenic zones in extratemporal epilepsy is a challenging problem. ... more abstract Localization of epileptogenic zones in extratemporal epilepsy is a challenging problem. We speculate that using all modalities of data in an optimal way can facilitate the localization of these zones. In this paper, we propose the following steps to transfer all modalities of data in a single reference coordinate system: 1) Segmentation of subdural and depth electrodes, and cortical surface. 2) Building 3D models of the segmented objects.
Objective: Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be... more Objective: Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be implicated in a variety of neuronal processes, including cell growth, resilience to noxious stimuli and synaptic plasticity. A Val to Met substitution at codon 66 in the BDNF protein has been associated with a variety of neuropsychiatric conditions. The ApoE4 allele is considered a risk factor for late-onset Alzheimer's disease, but its effects on young adults are less clear.
Abstract Several technologies for characterizing genes and proteins from humans and other organis... more Abstract Several technologies for characterizing genes and proteins from humans and other organisms use yeast growth or color development as read outs. The yeast two-hybrid assay, for example, detects protein-protein interactions by measuring the growth of yeast on a specific solid medium, or the ability of the yeast to change color when grown on a medium containing a chromogenic substrate.
This study assesses the utility of compartmental analysis of SPECT data in lateralizing ictal ons... more This study assesses the utility of compartmental analysis of SPECT data in lateralizing ictal onset in cases of a putative mesial temporal lobe epilepsy (mTLE). An institutional archival review provided 46 patients (18M, 28F) operated for a putative mTLE who achieved an Engel class Ia postoperative outcome. This established the standard to assure a true ictal origin.
ABSTRACT This paper presents a study on the SPECT images of the brain with the aim of determining... more ABSTRACT This paper presents a study on the SPECT images of the brain with the aim of determining the hippocampus abnormality and consequently applying timely treatment. Intensity and volume features of the hippocampus from brain MRI have been shown to be useful in detecting the abnormal hippocampus in TLE. In this study, we evaluate the intensity information of the SPECT images of the brain for the purpose of early detection of abnormal hippocampus, before the brain tissue is damaged and MRI features change.
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Papers by Hamid Soltanian-zadeh