Cited by 499Advanced MRI Techniques and ApplicationsNeurological diseases and metabolismAdvanced Neuroimaging Techniques and Applications

MRI estimates of brain iron concentration in normal aging using quantitative susceptibility mapping

Open access
Bilgic, Berkin, Pfefferbaum, Adolf, Rohlfing, Torsten, Sullivan, Edith V., Adalsteinsson, Elfar·2012·NeuroImage

Abstract

Quantifying tissue iron concentration in vivo is instrumental for understanding the role of iron in physiology and in neurological diseases associated with abnormal iron distribution. Herein, we use recently-developed Quantitative Susceptibility Mapping (QSM) methodology to estimate the tissue magnetic susceptibility based on MRI signal phase. To investigate the effect of different regularization choices, we implement and compare ℓ1 and ℓ2 norm regularized QSM algorithms. These regularized approaches solve for the underlying magnetic susceptibility distribution, a sensitive measure of the tissue iron concentration, that gives rise to the observed signal phase. Regularized QSM methodology also involves a pre-processing step that removes, by dipole fitting, unwanted background phase effects due to bulk susceptibility variations between air and tissue and requires data acquisition only at a single field strength. For validation, performances of the two QSM methods were measured against published estimates of regional brain iron from postmortem and in vivo data. The in vivo comparison was based on data previously acquired using Field-Dependent Relaxation Rate Increase (FDRI), an estimate of MRI relaxivity enhancement due to increased main magnetic field strength, requiring data acquired at two different field strengths. The QSM analysis was based on susceptibility-weighted images acquired at 1.5 T, whereas FDRI analysis used Multi-Shot Echo-Planar Spin Echo images collected at 1.5 T and 3.0 T. Both datasets were collected in the same healthy young and elderly adults. The in vivo estimates of regional iron concentration comported well with published postmortem measurements; both QSM approaches yielded the same rank ordering of iron concentration by brain structure, with the lowest in white matter and the highest in globus pallidus. Further validation was provided by comparison of the in vivo measurements, ℓ1-regularized QSM versus FDRI and ℓ2-regularized QSM versus FDRI, which again yielded perfect rank ordering of iron by brain structure. The final means of validation was to assess how well each in vivo method detected known age-related differences in regional iron concentrations measured in the same young and elderly healthy adults. Both QSM methods and FDRI were consistent in identifying higher iron concentrations in striatal and brain stem ROIs (i.e., caudate nucleus, putamen, globus pallidus, red nucleus, and substantia nigra) in the older than in the young group. The two QSM methods appeared more sensitive in detecting age differences in brain stem structures as they revealed differences of much higher statistical significance between the young and elderly groups than did FDRI. However, QSM values are influenced by factors such as the myelin content, whereas FDRI is a more specific indicator of iron content. Hence, FDRI demonstrated higher specificity to iron yet yielded noisier data despite longer scan times and lower spatial resolution than QSM. The robustness, practicality, and demonstrated ability of predicting the change in iron deposition in adult aging suggest that regularized QSM algorithms using single-field-strength data are possible alternatives to tissue iron estimation requiring two field strengths.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1016/j.neuroimage.2011.08.077

Cites

40 of 40 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Regional heterogeneity of brain iron and its change with age have both been confirmed in vivo by MRI.

    “Regional heterogeneity of brain iron and its change with age have both been confirmed in vivo by MRI.48–51”
  • Studies at high-field strength show that the confounding effect of myelin on T2* can be accounted for by including frequency information, which is normally discarded.

    “Additionally, studies at high-field strength show that the confounding effect of myelin on T2* can be accounted for by including frequency information, which is normally discarded.51,203,204”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Haacke EM Chengb NYC House MJ Liu Q Neelavalli J Ogg RJ Khan A Ayaz M Kirsch W Obenaus A 2005b Imaging iron stores in the brain using magnetic resonance imaging Magnetic Resonance Imaging 23 1 25 15733784

Cited by

Sorted by citations

Authors
Bilgic, B., Pfefferbaum, A., Rohlfing, T., Sullivan, E. V., & Adalsteinsson, E.
Affiliations
  • SRI International (US)
  • Stanford Medicine (US)
Venue
NeuroImage
Publisher
Elsevier BV
Published
2012-02
Volume
59
Issue
3
Pages
2625-2635
ISSN
1053-8119 (ISSN-L)
OpenAlex
W2019035911
Cited by
499
References
40
Citations by year
2026: 13 · 2025: 19 · 2024: 29 · 2023: 34 · 2022: 57 · 2021: 39 · 2020: 29 · 2019: 40 · 2018: 44 · 2017: 39 · 2016: 39 · 2015: 40 · 2014: 35 · 2013: 33 · 2012: 8
FWCI
18.58
Type
journal article
Language
en
Open access
Locations
  • NeuroImage (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
  • DSpace@MIT (Massachusetts Institute of Technology) (submittedVersion, cc-by-nc-nd)
  • PMC
Funders
  • National Institutes of Health
  • National Science Foundation (NSF)
  • Siemens Healthcare; Siemens-MIT Alliance
  • MIT-CIMIT Medical Engineering Fellowship
Topics
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced MRI Techniques and Applications
  • Life Sciences › Neuroscience › Neurology › Neurological diseases and metabolism
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced Neuroimaging Techniques and Applications
Keywords
quantitative susceptibility mapping, normal aging, magnetic susceptibility, regularization, L1 and L2 regularization, striatum, globus pallidus, brainstem, myelin content, dipole fitting, substantia nigra, red nucleus, caudate nucleus, putamen
MeSH terms
Adult, Aged, Aged, 80 and over, Aging, Algorithms, Brain, Brain Chemistry, Brain Mapping, Brain Stem, Cadaver, Corpus Striatum, Female, Fourier Analysis, Humans, Image Processing, Computer-Assisted, Iron, Magnetic Resonance Imaging, Male, Middle Aged, Thalamus, Reproducibility of Results, Young Adult

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review