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Susceptibility Source Separation Unveils Paramagnetic and Diamagnetic Trajectories in Healthy Brains From 5 to 90 Years.

Code ↔ Paper

4 matches between paragraphs of the paper and lines of its authors' code, computed by the harvester (lexical-v1). Click a colored paragraph or line to see its counterpart.

The 4 matches
  1. [1] § Methods › Susceptibility Source Separation Processing ↔ single_orientation/APART_QSM_single_ori_demo.m, lines 6–38 · score 0.83 · B0 field, B0 direction, magnitude images, brain mask, R2 map, APART QSM
  2. [2] § Methods › Susceptibility Source Separation Processing ↔ multi_orientation/APART_QSM_multi_ori_demo.m, lines 12–61 · score 0.83 · B0 field, B0 direction, magnitude images, brain mask, R2 map, APART QSM
  3. [3] § Methods › Relaxation Maps Reconstruction (R2, R2* and R2′) ↔ multi_orientation/APART_QSM_multi_ori_demo.m, lines 12–61 · score 0.52 · magnitude images, R2 maps, decay, echo
  4. [4] § Methods › Relaxation Maps Reconstruction (R2, R2* and R2′) ↔ single_orientation/APART_QSM_single_ori_demo.m, lines 6–38 · score 0.52 · magnitude images, R2 maps, decay, echo

Paper

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The authors' code

MATLAB · 58 lines · 2.3 KB · no license · 2 matches

  1. % Demo of APART-QSM using single-orientation data
  3. clear
  4. clc
  6. %% loading and setting
  8. % save path
  9. save_path = './results'; % please define the path to save results
  11. % input
  12. load('./single_orientation_data/mag_img.mat'); % magnitude image
  13. load('./single_orientation_data/phi_local_img.mat'); % local phase image
  14. load('./single_orientation_data/r2_img.mat'); % R2 map
  15. load('./single_orientation_data/chi_img.mat'); % initial STAR-QSM image
  16. load('./single_orientation_data/mask.mat'); % brain mask
  17. load('./single_orientation_data/TEs.mat'); % echo time
  19. % set mask
  20. params.mask = mask;
  22. % set parameters
  23. params.size = size(mag_img(:,:,:,1)); % matrix size
  24. params.voxel_size = [1, 1, 2]; % voxel size, unit: mm
  25. params.n_echo = length(TEs); % echo number
  26. params.TEs = TEs; % echo time, unit: s
  27. params.gamma = 42.576; % gyromagnetic ratio, unit: MHz/T
  28. params.B0 = 3; % B0 field, unit: T
  29. params.B0_dir = [0, 0, 1]; % B0 direction
  30. params.a = 323.5; % magnitude decay kernel unit: Hz/ppm
  32. % tolerance of the a-map relative change in two consecutive iterations
  33. params.tol_a = 0.3;
  35. % scaling weight
  36. params.lambda_r2prime = 0.1;
  37. params.lambda_chi = 10;
  38. params.lambda_TV = 1;
  40. %% exexcute APART-QSM
  41. Res_map = apart_qsm_single_ori(mag_img, phi_local_img, r2_img, chi_img, params);
  43. %% save results
  44. if ~exist(save_path,'dir')
  45. mkdir(save_path);
  46. end
  47. save_nii(make_nii(single(Res_map(:,:,:,1)), params.voxel_size), fullfile(save_path,'X_para.nii'));
  48. save_nii(make_nii(single(Res_map(:,:,:,2)), params.voxel_size), fullfile(save_path,'X_dia_abs.nii'));
  49. save_nii(make_nii(single(Res_map(:,:,:,3)), params.voxel_size), fullfile(save_path,'phase_res.nii'));
  50. save_nii(make_nii(single(Res_map(:,:,:,4)), params.voxel_size), fullfile(save_path,'a_map.nii'));
  51. save_nii(make_nii(single(Res_map(:,:,:,5)), params.voxel_size), fullfile(save_path,'M0.nii'));
  52. save_nii(make_nii(single(Res_map(:,:,:,6)), params.voxel_size), fullfile(save_path,'R2star.nii'));
  53. save_nii(make_nii(single(Res_map(:,:,:,7)), params.voxel_size), fullfile(save_path,'R2prime.nii'));
  54. save_nii(make_nii(single(Res_map(:,:,:,1) - Res_map(:,:,:,2)), params.voxel_size), fullfile(save_path,'X_composite.nii'));

APART_QSM_single_ori_demo.m at commit c49bad4, no license · at the source

Overview

Authors: Tereza Beatriz Oliveira Assunção1, Nashwan Naji1,2, Peter Seres2, Christian Beaulieu1,2, Alan H. Wilman1,2
ORCID iDs: Tereza Beatriz Oliveira Assunção, Nashwan Naji, Christian Beaulieu
  1. Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
  2. Department of Radiology and Diagnostic Imaging University of Alberta Edmonton Alberta Canada
Institutions: University of Alberta (Canada)
Journal: NMR in biomedicine, volume 39, issue 8, article e70349
Dates: received 6 March 2026; accepted 4 June 2026; published online 6 July 2026; in print August 2026
Type: Research article · Language: English
License: CC BY
Identifiers: DOI 10.1002/nbm.70349 · PMID 42405451 · PMCID PMC13334517 · OpenAlex W7167498146
Open access: hybrid, a free copy (OpenAlex)
Status: code verified
Categories: structural MRI / diffusion (modality), human (organism), developmental (subfield)
Methods: Statistics, Connectivity, fMRI & imaging
Keywords: healthy lifespan, human brain, source separation, susceptibility
MeSH: Brain*, Magnetic Phenomena*, Magnetic Resonance Imaging*, Adolescent, Adult, Aged, Aged, 80 and over, Aging, Child, Child, Preschool, Female, Humans, Male, Middle Aged, White Matter, Young Adult (* major topic)
Topic: Advanced MRI Techniques and Applications (Radiology, Nuclear Medicine and Imaging, Medicine), according to OpenAlex
Funding: University Hospital Foundation; Canadian Institutes of Health Research
Citations: not cited yet (Europe PMC); 49 references in the paper

Abstract

Susceptibility source separation (SSS) enables independent evaluation of both paramagnetic iron and diamagnetic myelin in the human brain. The aim of this work was to analyze healthy brain lifespan trajectories of paramagnetic and diamagnetic susceptibilities in deep gray matter (DGM) and white matter (WM) from a large database (339 subjects, 5 to 90 years), all acquired at 3 T on the same scanner, using χ‐separation and comparing it to two other common SSS methods (χ‐sepnet and APART‐QSM). A 3D multiple echo gradient echo sequence was used to measure phase, R2* and QSM, as well as dual echo fast spin echo to measure R2. The mean value of WM and DGM regions was calculated for SSS output maps and plotted against age to evaluate trajectories across the lifespan. With χ‐separation, most DGM regions showed an increasing trend with age in the paramagnetic map, except for thalamus, which showed an inverted‐U quadratic trajectory, and all DGM regions showed an increase in diamagnetic content with age. In WM, for the paramagnetic maps, body of corpus callosum, splenium and corticospinal tract showed an inverted quadratic trajectory, cingulum an increasing exponential, while no significant changes were seen in genu. For the diamagnetic WM maps, all regions followed a similar trajectory, increase in early life, peak around 40 to 60 years, and decrease with age. The different SSS approaches yielded different curve shapes and mean values in many instances. For example, APART‐QSM had consistently lower ppb values, χ‐sepnet had biologically unexpected results for early ages, and χ‐separation data had higher standard deviation of best‐fit residuals when compared to the other evaluated methods for all analyzed regions and maps. All SSS methods enabled depiction of independent iron and myelin trends; however, different results between methods suggest caution in choosing SSS methods and the need for further methodological advances.

Reproduced under the paper's license (CC BY), from the paper cited above.

Repositories

Its files are read in the Code ↔ Paper reader above, with 4 matches between paragraphs and lines of code.

SNU-LIST/chi-separation

License: none: the authors keep all their rights
State: the link answers, verified on 26 September 2026
Evidence: files inventoried
Commit: 29f901c39c70cf71eca4ba46cd8da2a67d16d874, 3 June 2026
Size: 1 file, 0 scripts
Software Heritage: not archived
Found in: the text, “Susceptibility Source Separation Processing”
Holds: README
Not found: license file, CITATION.cff, environment file, tests, continuous integration, documentation
Availability: 1 check, the latest on 26 September 2026: the link answers
  • 26 September 2026: the link answers
1 file
At the source: github.com/SNU-LIST/chi-separation

SNU-LIST/chi_sepnet

License: other
State: the link answers, verified on 26 September 2026
Evidence: files inventoried
Commit: 99ea6e6260b596fba2eeda42326da7129513e9de, 12 September 2025
Languages: Python (9)
Size: 14 files, 9 scripts
Software Heritage: not archived
Found in: the text, “Susceptibility Source Separation Processing”
Holds: README, license file
Not found: CITATION.cff, environment file, tests, continuous integration, documentation
Tools: NumPy (6 files), PyTorch (5 files), SciPy (4 files), h5py (3 files), Matplotlib (2 files), scikit-image (1 file)
Availability: 1 check, the latest on 26 September 2026: the link answers
  • 26 September 2026: the link answers
10 files
At the source: github.com/SNU-LIST/chi_sepnet

AMRI-Lab/APART-QSM

License: none: the authors keep all their rights
State: the link answers, verified on 26 September 2026
Evidence: files inventoried
Commit: c49bad4301b35c430a21a29154180ed18ba94966, 31 March 2025
Languages: MATLAB (11)
Size: 32 files, 11 scripts
Software Heritage: not archived
Found in: the text, “Susceptibility Source Separation Processing”
Holds: README
Not found: license file, CITATION.cff, environment file, tests, continuous integration, documentation
Tools: Tools for NIfTI and ANALYZE image (MATLAB) (2 files)
Availability: 1 check, the latest on 26 September 2026: the link answers
  • 26 September 2026: the link answers
12 files
At the source: github.com/AMRI-Lab/APART-QSM

The paper's code and data availability statement is in the Data section.

Tracing map

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What the map holds:

  • 3 repositories of the authors' code, each at its verified commit, with its license and how the link was found in the paper;
  • 20 scripts, each with its path and the digest of its content;
  • 4 matches between paragraphs of the paper and lines of the code (method lexical-v1);
  • neither the text of the paper nor the code itself.

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Data

Datasets cited

Data Availability Statement

The measurements (mean value per subject with age and sex, for all reported regions and metrics—χpara, χdia, QSM, R2′ and R2*) and analysis scripts of this study are available from the corresponding author upon request. Participant MRI images and maps are not publicly available due to ethical considerations.

Reproduced under the paper's license (CC BY), from the paper cited above.

Versions

The history of this record: each version stored by the harvester or made by a correction of its authors or of the maintainers of its code, and what changed in its facts. The texts of the paper (its abstract, its availability statements) are not part of it; versions that changed only those are not listed.

Version 3, 28 September 2026

  • Publisher: n/a → Wiley

Version 1, 27 September 2026: the first record

Recorded: type, language, journal, volume, issue, pages, dates, 5 authors, 4 keywords, 16 MeSH terms, 2 funders, 47 references.

Cite

This paper

Assunção, T. B. O., Naji, N., Seres, P., Beaulieu, C., & Wilman, A. H. (2026). Susceptibility Source Separation Unveils Paramagnetic and Diamagnetic Trajectories in Healthy Brains From 5 to 90 Years. NMR in biomedicine, 39(8), e70349. https://doi.org/10.1002/nbm.70349

BibTeX

@article{assuncao2026susceptibility,
author = {Assunção, Tereza Beatriz Oliveira and Naji, Nashwan and Seres, Peter and Beaulieu, Christian and Wilman, Alan H.},
title = {{Susceptibility Source Separation Unveils Paramagnetic and Diamagnetic Trajectories in Healthy Brains From 5 to 90 Years}},
journal = {NMR in biomedicine},
year = {2026},
month = aug,
volume = {39},
number = {8},
pages = {e70349},
publisher = {Wiley},
issn = {0952-3480},
doi = {10.1002/nbm.70349},
url = {https://doi.org/10.1002/nbm.70349},
pmid = {42405451},
pmcid = {PMC13334517}
}

RIS

TY - JOUR
AU - Assunção, Tereza Beatriz Oliveira
AU - Naji, Nashwan
AU - Seres, Peter
AU - Beaulieu, Christian
AU - Wilman, Alan H.
TI - Susceptibility Source Separation Unveils Paramagnetic and Diamagnetic Trajectories in Healthy Brains From 5 to 90 Years
T2 - NMR in biomedicine
J2 - NMR Biomed
PY - 2026
DA - 2026/08/01
VL - 39
IS - 8
SP - e70349
SN - 0952-3480
PB - Wiley
DO - 10.1002/nbm.70349
UR - https://doi.org/10.1002/nbm.70349
LA - en
ER -

CSL-JSON

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"id": "10.1002/nbm.70349",
"type": "article-journal",
"title": "Susceptibility Source Separation Unveils Paramagnetic and Diamagnetic Trajectories in Healthy Brains From 5 to 90 Years",
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"author": [
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"given": "Tereza Beatriz Oliveira"
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"container-title-short": "NMR Biomed",
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"issue": "8",
"page": "e70349",
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"PMID": "42405451",
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"ISSN": "0952-3480",
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2026,
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}

The tracing map gets a citation of its own once an author has validated it and it has a DOI.

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