equipment-setup-artifact-removal-for-simultaneous

Equipment Setup and Artifact Removal for Simultaneous Electroencephalogram and Functional Magnetic Resonance Imaging for Clinical Review in Epilepsy

Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that provides synergy in the ...

University of Kentucky

A foundational framework for understanding functional and dysfunctional imaging of episodic memory emerges from the last 3 decades of human and animal research. This comprehensive review is presented from the vantage point of the fornix, a white matter bridge that occupies a central position in this functional network. Salient insights are identified, spanning topics such as hippocampal efferent and afferent networks, input and processing streams, hemispheric specialization, dysfunctional effects of pathologic and surgical injury, optimization of functional magnetic resonance imaging design and neuropsychological tests, and rehabilitation strategies. Far-reaching implications are considered for radiologists, whose clinical effect stretches beyond imaging and interfaces with neurosurgeons, neuropsychologists, and other neurospecialists.

Imaging of Functional and Dysfunctional Episodic Memory.

Surfer's myelopathy (SM) is a rare disorder described in subjects presenting with acute paraparesis while learning how to surf. It is thought to be secondary to spinal ischemia triggered by hyperextension. Spinal magnetic resonance imaging (MRI) shows changes consistent with spinal cord ischemia on T2-weighted and diffusion-weighted imaging (DWI).

Surfer's myelopathy without surfing: a report of two pediatric patients.

Pearls & Oy-sters: An uncommon initial presentation of thyrotoxicosis.

Movement disorders are uncommon manifestations of neurocysticercosis. When present, most are secondary to parenchymal lesions in the basal ganglia. Rarely, movement disorders can occur in racemose/extraparenchymal neurocysticercosis, an aggressive variant frequently associated with cerebrospinal fluid outflow obstruction and hydrocephalus. Appropriate treatment can reverse neurological manifestations.

Reversible manifestations of extraparenchymal neurocysticercosis.

Interpretation of fMRI depends on accurate functional-to-structural alignment. This study explores registration methods used by FDA-approved software for clinical fMRI and aims to answer the following question: What is the degree of misalignment when registration is not performed, and how well do current registration methods perform?

Peeking into the Black Box of Coregistration in Clinical fMRI: Which Registration Methods Are Used and How Well Do They Perform?

Iterative reconstruction has promise in lowering the radiation dose without compromising image quality, but its full potential has not yet been realized. While phantom studies cannot fully approximate the subjective effects on image quality, live animal models afford this assessment. We characterize dose reduction in head CT by applying advanced modeled iterative reconstruction (ADMIRE) in a live ovine model while evaluating preservation of gray-white matter detectability and image texture compared with filtered back-projection.

Dose Reduction While Preserving Diagnostic Quality in Head CT: Advancing the Application of Iterative Reconstruction Using a Live Animal Model.

Pearls & Oy-sters: Progressive ataxia and palatal tremor: Imaging and disease course.

Excessive brain iron negatively affects working memory and related processes but the impact of cortical iron on task-relevant, cortical brain networks is unknown. We hypothesized that high cortical iron concentration may disrupt functional circuitry within cortical networks supporting working memory performance. Fifty-five healthy older adults completed an N-Back working memory paradigm while functional magnetic resonance imaging (fMRI) was performed. Participants also underwent quantitative susceptibility mapping (QSM) imaging for assessment of non-heme brain iron concentration. Additionally, pseudo continuous arterial spin labeling scans were obtained to control for potential contributions of cerebral blood volume and structural brain images were used to control for contributions of brain volume. Task performance was positively correlated with strength of task-based functional connectivity (tFC) between brain regions of the frontoparietal working memory network. However, higher cortical iron concentration was associated with lower tFC within this frontoparietal network and with poorer working memory performance after controlling for both cerebral blood flow and brain volume. Our results suggest that high cortical iron concentration disrupts communication within frontoparietal networks supporting working memory and is associated with reduced working memory performance in older adults.

Cortical iron disrupts functional connectivity networks supporting working memory performance in older adults.

To investigate the potential of iterative reconstruction in radiation dose reduction during head computed tomography (CT) examinations and to evaluate the relationship between the parameters milliampere second (mAs), kilovoltage (kV), and iterative reconstruction strength using a live ovine (sheep) model.

Iterative Reconstruction in Dose Reduction of A Head CT Examination and Corresponding Acquisition Parameter Selection.

While simulated low-dose CT images and phantom studies cannot fully approximate subjective and objective effects of deep learning (DL) denoising on image quality, live animal models may afford this assessment. This study is to investigate the potential of DL in CT dose reduction on image quality compared to iterative reconstruction (IR).The upper abdomen of a live 4 year old sheep was scanned on a CT scanner at different exposure levels. Images were reconstructed using FBP and ADMIRE with 5 strengths. A modularized DL network with 5 modules was used for image reconstruction via progressive denoising. Radiomic features were extracted from a region over the liver. Concordance correlation coefficient (CCC) was applied to quantify agreement between any two sets of radiomic features. Coefficient of variation was calculated to measure variation in a radiomic feature series. Structural similarity index (SSIM) was used to measure the similarity between any two images. Diagnostic quality, low-contrast detectability, and image texture were qualitatively evaluated by two radiologists. Pearson correlation coefficient was computed across all dose-reconstruction/denoising combinations.A total of 66 image sets, with 405 radiomic features extracted from each, are analyzed. IR and DL can improve diagnostic quality and low-contrast detectability and similarly modulate image texture features. In terms of SSIM, DL has higher potential in preserving image structure. There is strong correlation between SSIM and radiologists' evaluations for diagnostic quality (0.559) and low-contrast detectability (0.635) but moderate correlation for texture (0.313). There is moderate correlation between CCC of radiomic features and radiologists' evaluation for diagnostic quality (0.397), low-contrast detectability (0.417), and texture (0.326), implying that improvement of image features may not relate to improvement of diagnostic quality.DL shows potential to further reduce radiation dose while preserving structural similarity, while IR is favored by radiologists and more predictably alters radiomic features.

Deep learning versus iterative reconstruction on image quality and dose reduction in abdominal CT: a live animal study.

Emerging evidence suggests that enlarged perivascular spaces (ePVS) may be a clinically significant neuroimaging marker of global cognitive function related to cerebral small vessel disease (cSVD). We tested this possibility by assessing the relationship between ePVS and both a standardized measure of global cognitive function, the Montreal Cognitive Assessment (MoCA), and an established marker of cSVD, white matter hyperintensity volume (WMH) volume. One hundred and eleven community-dwelling older adults (56-86) underwent neuroimaging and MoCA testing. Quantification of region-specific ePVS burden was performed using a previously validated visual rating method and WMH volumes were computed using the standard ADNI pipeline. Separate linear regression models were run with ePVS as a predictor of MoCA scores and whole brain WMH volume. Results indicated a negative association between MoCA scores and both total ePVS counts ( ≤ 0.001) and centrum semiovale ePVS counts ( ≤ 0.001), after controlling for other relevant cSVD variables. Further, WMH volumes were positively associated with total ePVS ( = 0.010), basal ganglia ePVS ( ≤ 0.001), and centrum semiovale ePVS ( = 0.027). Our results suggest that ePVS burden, particularly in the centrum semiovale, may be a clinically significant neuroimaging marker of global cognitive dysfunction related to cSVD.

Article	Year
Imaging of Functional and Dysfunctional Episodic Memory. Seminars in ultrasound, CT, and MR\| PubMed ID: 26233860	2015
Surfer's myelopathy without surfing: a report of two pediatric patients. Spinal cord series and cases\| PubMed ID: 28382219	2017
Pearls & Oy-sters: An uncommon initial presentation of thyrotoxicosis. Neurology\| PubMed ID: 28784643	2017
Reversible manifestations of extraparenchymal neurocysticercosis. Clinical case reports\| PubMed ID: 29988662	2018
Peeking into the Black Box of Coregistration in Clinical fMRI: Which Registration Methods Are Used and How Well Do They Perform? AJNR. American journal of neuroradiology\| PubMed ID: 30361428	2018
Dose Reduction While Preserving Diagnostic Quality in Head CT: Advancing the Application of Iterative Reconstruction Using a Live Animal Model. AJNR. American journal of neuroradiology\| PubMed ID: 31601574	2019
Pearls & Oy-sters: Progressive ataxia and palatal tremor: Imaging and disease course. Neurology\| PubMed ID: 32107322	2020
Cortical iron disrupts functional connectivity networks supporting working memory performance in older adults. NeuroImage\| PubMed ID: 32861788	2020
Iterative Reconstruction in Dose Reduction of A Head CT Examination and Corresponding Acquisition Parameter Selection. Radiologic technology\| PubMed ID: 35508407	2022
Deep learning versus iterative reconstruction on image quality and dose reduction in abdominal CT: a live animal study. Physics in medicine and biology\| PubMed ID: 35709707	2022
Enlarged Perivascular Spaces Are Negatively Associated With Montreal Cognitive Assessment Scores in Older Adults. Frontiers in neurology\| PubMed ID: 35847209	2022

Flavius D. Raslau

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