{
  "abstract": "Purpose: To complement 1.5-minute measurements of common tensor-valued diffusion MRI (dMRI) markers with rapid constrained fitting. Methods: Fast dMRI protocols for obtaining rotational invariants of the cumulant expansion (RICE) were paired with constrained weighted linear least squares (CWLLS) to stabilize the more fragile WLLS fit. A compact constraint set was formulated, including a novel mean-dependent upper bound on total diffusional variance. Evaluation used diffusion tensor distribution (DTD) simulations, healthy-volunteer data with a resolution-dependent SNR experiment, and a glioma patient dataset. A 5-minute q-space trajectory imaging (QTI) protocol served as a reference. Results: Across experiments, CWLLS reduced unphysical estimates and fit outliers in parameters such as microscopic FA and isotropic diffusivity variance. In simulations, it narrowed error distributions most clearly in the CSF-dominant case, while some metrics showed a bias-variance trade-off. In vivo, CWLLS removed negative variance estimates, truncated out-of-bounds tails, and reduced artifacts in fluid-contaminated voxels while preserving anatomical contrast. It also retained more stable maps than WLLS at higher resolution, although both estimators degraded in the lowest-SNR setting. Notably, the new mean-dependent variance bound was violated in 15.4% of voxels in the patient dataset, accounting for nearly half of the 32.7% that violated at least one constraint. Healthy-volunteer benchmarking showed that CWLLS completed in under 30 seconds. The constrained QTI fit required 72 minutes, making CWLLS 160 times faster. Conclusion: CWLLS for fast RICE yielded high-quality parameter maps at an online-ready computational cost. This may enhance the reliability of dMRI tissue characterization and strengthen the path toward clinical translation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.27212",
  "author_total": 13,
  "authors": [
    {
      "name": "Jinyang Yu"
    },
    {
      "name": "Oliver Gödicke"
    },
    {
      "name": "Frederik B. Laun"
    },
    {
      "name": "Obada T. Alhalabi"
    },
    {
      "name": "Iris A. Kohler"
    },
    {
      "name": "Jürgen Hesser"
    },
    {
      "name": "Sandro M. Krieg"
    },
    {
      "name": "Bogdana Suchorska"
    },
    {
      "name": "Heinz-Peter Schlemmer"
    },
    {
      "name": "Mark E. Ladd"
    },
    {
      "name": "David Bonekamp"
    },
    {
      "name": "Johann M. E. Jende"
    },
    {
      "name": "Tristan A. Kuder"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aahf4ew2qc0gg.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.27212",
  "fulltext_url": null,
  "id": "aahf4ew2qc0gg",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.27212",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.med-ph"
    ],
    [
      "openalex",
      "2741|Advanced Neuroimaging Techniques and Applications"
    ]
  ],
  "openalex": "W7204566774",
  "pdf_url": "https://arxiv.org/pdf/2608.27212",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/aahf4ew2qc0gg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2608.27212",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.27212"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.med-ph",
      "subfield": "biological-medical"
    }
  ],
  "title": "Constrained estimation of rotational invariants of the cumulant expansion (RICE) for rapid tensor-valued diffusion MRI",
  "title_text": "Constrained estimation of rotational invariants of the cumulant expansion (RICE) for rapid tensor-valued diffusion MRI",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:56Z",
  "url": "https://research.draconitic.com/paper/aahf4ew2qc0gg",
  "venue": "arXiv",
  "versions": []
}