Iterative estimation of MRI sensitivity maps and image based on sense reconstruction method (<i>i</i>sense)
Bibliographic record
Abstract
Abstract SENSitivity Encoding (SENSE) is a parallel MR image reconstruction technique that yields optimal results when the sensitivity maps are accurately known. Unfortunately, in practical scenarios, obtaining accurate estimates of the sensitivity maps is not possible. In this work, we propose a technique that iteratively reconstructs the image and refines the sensitivity maps (from initial estimates). Our technique is named iSENSE (iterative SENSE). Our proposed technique exploits the sparsity of the MR image in some transform domains or the rank deficiency characteristic of the matrix representing the MRI image; the former leads to a compressed sensing‐based reconstruction method, whereas the latter leads to an image reconstruction method that minimizes the nuclear norm (NN) of the image matrix. The sensitivity maps are assumed to be rank‐deficient matrices, and thus the refinement of the sensitivity maps is achieved via the NN minimization. To evaluate the performance of the proposed method, we have carried out the experiments on real and one simulated datasets. We have compared our method with three state‐of‐the‐art image domain methods—SparSENSE (Sparse SENSE), NNSENSE (NN Regularized SENSE), and JSENSE (Joint SENSE reconstruction)—and one widely used frequency domain method—GRAPPA (Generalized Autocalibrating Partially Parallel Acquisition). Our method yields the best reconstruction results both in quantitative (normalized mean‐squared error) and qualitative (visual inspection of reconstructed and difference images) evaluation. © 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part A 40A: 269–280, 2012.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".