Publications by authors named "Hoyt Taylor"

Delineating the normative developmental profile of functional connectome is important for both standardized assessment of individual growth and early detection of diseases. However, functional connectome has been mostly studied using functional connectivity (FC), where undirected connectivity strengths are estimated from statistical correlation of resting-state functional MRI (rs-fMRI) signals. To address this limitation, we applied regression dynamic causal modeling (rDCM) to delineate the developmental trajectories of effective connectivity (EC), the directed causal influence among neuronal populations, in whole-brain networks from infancy to adolescence (0-22 years old) based on high-quality rs-fMRI data from Baby Connectome Project (BCP) and Human Connectome Project Development (HCP-D).

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Dynamic Functional Connectome Harmonics.

Med Image Comput Comput Assist Interv

October 2023

Functional connectivity (FC) "gradients" enable investigation of connection topography in relation to cognitive hierarchy, and yield the primary axes along which FC is organized. In this work, we employ a variant of the "gradient" approach wherein we solve for the normal modes of FC, yielding functional connectome harmonics. Until now, research in this vein has only considered static FC, neglecting the possibility that the principal axes of FC may depend on the timescale at which they are computed.

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Recent evidence indicates that the organization of the human neocortex is underpinned by smooth spatial gradients of functional connectivity (FC). These gradients provide crucial insight into the relationship between the brain's topographic organization and the texture of human cognition. However, no studies to date have charted how intrinsic FC gradient architecture develops across the entire human lifespan.

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Article Synopsis
  • The study aimed to investigate the effects of the Orbital Atherectomy System (OAS) on vascular health in patients with peripheral arterial disease (PAD) and calcified lesions, assessing both immediate and long-term outcomes.
  • This involved evaluating 7 patients before and six months after treatment using a combination of diagnostic angiograms and intravascular optical coherence tomography (IV-OCT).
  • Results showed a 6% average increase in luminal volume after treatment, with most plaque removed being fibrous tissue, and a new algorithm for IV-OCT image classification was validated against expert analysis with 82% agreement.
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Most brain microstructure models are dedicated to the quantification of white matter microstructure, using for example sticks, cylinders, and zeppelins to model intra- and extra-axonal environments. Gray matter presents unique micro-architecture with cell bodies (somas) exhibiting diffusion characteristics that differ from axons in white matter. In this paper, we introduce a method to quantify soma microstructure, giving measures such as volume fraction, diffusivity, and kurtosis.

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This study assessed stent healing patterns and cardiovascular outcomes by optical coherence tomography (OCT) in cancer patients after drug-eluting stent (DES) placement. Cancer treatment, owing to its cytotoxic and antiproliferative effects, could delay stent healing and increase stent thrombosis risk, especially when dual antiplatelet therapy (DAPT) is discontinued early for oncological treatment. OCT can assess stent endothelialization and other healing parameters, which may provide clinical guidance in these challenging scenarios.

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In order to assess the vascular effects of rotational orbital atherectomy, we performed intravascular imaging with virtual histology intravascular optical coherence tomography in a 72-year-old man with critical limb ischemia of the right lower extremity.

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Cerebellar abnormalities are commonly reported in autism spectrum disorder (ASD). Dentate nuclei (DNs) are key structures in the anatomical circuits linking the cerebellum to the extracerebellum. Previous resting-state functional connectivity (RsFc) analyses reported DN abnormalities in high-functioning ASD (HF-ASD).

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Meaningful division of the human cortex into distinct regions is a longstanding goal in neuroscience. Many of the most widely cited parcellations utilize anatomical priors or depend on functional magnetic resonance imaging (MRI) data while there exists a relative dearth of parcellations that use only structural data based on diffusion MRI. In light of this, and the fact that structural connectivity represents the underlying substrates of functional connectivity, we employ a novel high-resolution, vertex-level graph model of the whole-brain structural connectome and show that the harmonic modes of this graph can be used to achieve parcellations that qualitatively agree with the widely accepted atlases in the literature.

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Purpose: Zilver PTX nitinol self-expanding drug-eluting stent with paclitaxel coating is effective for treatment of superficial femoral artery (SFA) disease. However, as with any stent, it induces a measure of vascular inflammatory response. The current clinical trial (NCT02734836) aimed to assess vascular patency, remodeling, and inflammatory markers with intravascular optical coherence tomography (OCT) in patients with SFA disease treated with Zilver PTX stents.

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Purpose: To compare OCT identified white thrombus decline, neointimal hyperplasia and clinical outcomes of patients treated with ticagrelor plus aspirin with those patients treated with clopidogrel plus aspirin after peripheral interventions.

Background: Ticagrelor is a potent platelet inhibitor. In patients with coronary artery disease, ticagrelor and aspirin demonstrated reduced rates of stent thrombosis, compared to aspirin and clopidogrel.

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To quantitatively evaluate the change of plaque complexity with cholesterol lowering therapy. A total of 44 non-culprit plaques from 30 patients who had serial image acquisition at baseline, 6-months, and 12-months by both optical coherence tomography (OCT) and intravascular ultrasound (IVUS) were included. Patients were treated with atorvastatin 60 mg (AT60, n = 16) or 20 mg (AT20, n = 14).

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Background: Intravascular optical coherence tomography (IVOCT) images are recorded by detecting light backscattered within coronary arteries. We hypothesize that non-thin-capped fibroatheroma (TCFA) causes may scatter light to create the false appearance of IVOCT TCFA.

Methods And Results: Ten human cadaver hearts were imaged with IVOCT (n=14 coronary arteries).

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To investigate the clinical significance of bright spots in coronary plaque detected by optical coherence tomography (OCT) in patients with coronary artery disease. We identified 112 patients [acute coronary syndromes (ACS): n = 50, stable angina pectoris (SAP): n = 62] who underwent OCT imaging of the culprit lesion. A novel OCT algorithm was applied to detect bright spots representing the juxtaposition of a variety of plaque components including macrophages.

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Objectives: This study hypothesized that bright spots in intravascular optical coherence tomography (IVOCT) images may originate by colocalization of plaque materials of differing indexes of refraction. To quantitatively identify bright spots, we developed an algorithm that accounts for factors including tissue depth, distance from light source, and signal-to-noise ratio. We used this algorithm to perform a bright spot analysis of IVOCT images and compared these results with histological examination of matching tissue sections.

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