eprintid: 10059597
rev_number: 40
eprint_status: archive
userid: 608
dir: disk0/10/05/95/97
datestamp: 2018-10-26 13:13:42
lastmod: 2021-09-26 22:27:59
status_changed: 2019-02-12 17:09:48
type: article
metadata_visibility: show
creators_name: Karsa, A
creators_name: Punwani, S
creators_name: Shmueli, K
title: The effect of low resolution and coverage on the accuracy of susceptibility mapping
ispublished: pub
divisions: UCL
divisions: B02
divisions: C10
divisions: D17
divisions: FI6
divisions: B04
divisions: C05
divisions: F42
keywords: QSM accuracy, decreased contrast, low resolution, magnetic susceptibility, magnetic susceptibility mapping, reduced field-of-view
note: © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original
work is properly cited.
abstract: PURPOSE: Quantitative susceptibility mapping (QSM) has found increasing clinical applications. However, to reduce scan time, clinical acquisitions often use reduced resolution and coverage, particularly in the through-slice dimension. The effect of these factors on QSM has begun to be assessed using only balloon phantoms and downsampled brain images. Here, we investigate the effects (and their sources) of low resolution or coverage on QSM using both simulated and acquired images. METHODS: Brain images were acquired at 1 mm isotropic resolution and full brain coverage, and low resolution (up to 6 mm slice thickness) or coverage (down to 20 mm) in 5 healthy volunteers. Images at reduced resolution or coverage were also simulated in these volunteers and in a new, anthropomorphic, numerical phantom. Mean susceptibilities in 5 brain regions, including white matter, were investigated over varying resolution and coverage. RESULTS: The susceptibility map contrast decreased with increasing slice thickness and spacing, and with decreasing coverage below ~40 mm for 2 different QSM pipelines. Our simulations showed that calculated susceptibility values were erroneous at low resolution or very low coverage, because of insufficient sampling and overattenuation of the susceptibility-induced field perturbations. Susceptibility maps calculated from simulated and acquired images showed similar behavior. CONCLUSIONS: Both low resolution and low coverage lead to loss of contrast and errors in susceptibility maps. The widespread clinical practice of using low resolution and coverage does not provide accurate susceptibility maps. Simulations in images of healthy volunteers and in a new, anthropomorphic numerical phantom were able to accurately model low-resolution and low-coverage acquisitions.
date: 2019-03
date_type: published
official_url: http://dx.doi.org/10.1002/mrm.27542
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
article_type_text: Journal Article
verified: verified_manual
elements_id: 1596672
doi: 10.1002/mrm.27542
lyricists_name: Karsa, Anita
lyricists_name: Punwani, Shonit
lyricists_name: Shmueli, Karin
lyricists_id: AKARS34
lyricists_id: SPUNW14
lyricists_id: KSHMU54
actors_name: Cuccu, Clara
actors_id: CCCUC40
actors_role: owner
full_text_status: public
publication: Magnetic Resonance in Medicine
volume: 81
number: 3
pagerange: 1833-1848
event_location: United States
issn: 1522-2594
citation:        Karsa, A;    Punwani, S;    Shmueli, K;      (2019)    The effect of low resolution and coverage on the accuracy of susceptibility mapping.                   Magnetic Resonance in Medicine , 81  (3)   pp. 1833-1848.    10.1002/mrm.27542 <https://doi.org/10.1002/mrm.27542>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10059597/7/Karsa%20VoR%20Karsa_et_al-2019-Magnetic_Resonance_in_Medicine.pdf