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Record W7132994189

Spatial Subspace Methods for Dynamic Magnetic Resonance Imaging Reconstruction

2024· dissertation· W7132994189 on OpenAlexaff
Alexander James Mertens

Bibliographic record

VenueTSpace · 2024
Typedissertation
Language
FieldMedicine
TopicAdvanced MRI Techniques and Applications
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsSubspace topologyModality (human–computer interaction)Iterative reconstructionPattern recognition (psychology)Magnetic resonance imagingImage qualityReal-time MRISpatial analysis
DOInot available

Abstract

fetched live from OpenAlex

Data acquisition in magnetic resonance imaging (MRI) is a slow process. Despite being an over- whelmingly safe modality with excellent tissue contrast and diagnostic ability, long and expensive scans prevent its widespread clinical uptake. Current solutions to this problem operate by acquiring less data than typically required for MRI image reconstruction and developing techniques to estimate the unacquired data. In this work, we propose a new approach to reconstructing dynamic MRI data (i.e., MRI video of anatomy over time). Our new approach can be generally summarized by first esti- mating a spatial subspace from data acquired during the scan of interest (i.e., no prior training data required), then applying the spatial subspace to estimate the final reconstruction. This works well because the number of coefficients to estimate for spatial subspace reconstruction is usually small enough to enable a over/well-determined reconstruction problem, given that the spatial subspace is well estimated. This is not the case for common temporal subspace methods, for which the number of coefficients to estimate is large, and the problem is usually underdetermined. We apply our new approach to dynamic contrast-enhanced (DCE) MRI, MR Fingerprinting (MRF), and CINE MRI. In each case, we compare our spatial subspace methods to the gold standard and show the relative improvement in reconstruction quality of our methods.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.004
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.004
Threshold uncertainty score0.014

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.004
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0010.002
Science and technology studies0.0000.001
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.002
Insufficient payload (model declined to judge)0.0040.002

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.016
GPT teacher head0.447
Teacher spread0.431 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2024
Admission routes1
Has abstractyes

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