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Super-Resolution Cine Image Enhancement for Fetal Cardiac Magnetic Resonance Imaging

Berggren, Klas LU ; Ryd, Daniel LU ; Heiberg, Einar LU ; Aletras, Anthony LU orcid and Hedström, Erik LU orcid (2022) In Journal of Magnetic Resonance Imaging 56(1). p.223-231
Abstract
Background
Fetal cardiac magnetic resonance imaging (MRI) improves the diagnosis of congenital heart defects, but is sensitive to fetal motion due to long image acquisition time. This may be overcome with faster image acquisition with low resolution, followed by image enhancement to provide clinically useful images.

Purpose
To combine phase-encoding undersampling with super-resolution neural networks to achieve high-resolution fetal cine cardiac MR images with short acquisition time.
Study Type
Prospective.

Subjects
Twenty-eight fetuses (gestational week 36 [interquartile range 33–38 weeks]).

Field Strength/Sequence
1.5 T, balanced steady-state free precession (bSSFP) cine... (More)
Background
Fetal cardiac magnetic resonance imaging (MRI) improves the diagnosis of congenital heart defects, but is sensitive to fetal motion due to long image acquisition time. This may be overcome with faster image acquisition with low resolution, followed by image enhancement to provide clinically useful images.

Purpose
To combine phase-encoding undersampling with super-resolution neural networks to achieve high-resolution fetal cine cardiac MR images with short acquisition time.
Study Type
Prospective.

Subjects
Twenty-eight fetuses (gestational week 36 [interquartile range 33–38 weeks]).

Field Strength/Sequence
1.5 T, balanced steady-state free precession (bSSFP) cine sequence.

Assessment
Images were acquired using fully sampled Doppler ultrasound-gated clinical bSSFP cine as reference, with equivalent cine sequences with decreased phase-encoding resolution (25%, 33%, and 50% of clinical standard). Two super-resolution methods based on convolutional neural networks were proposed and evaluated (phasrGAN and phasrresnet). Data were partitioned into training (36 cine slices), validation (3 cine slices), and test sets (67 cine slices) without overlap. Conventional reconstruction methods using bicubic interpolation and k-space zeropadding were used for comparison. Three blinded observers scored image quality between 1 and 10.

Statistical Tests
Image scores are reported as median [interquartile range] and were compared using Mann–Whitney's nonparametric test with P < 0.05 showing statistically significant differences.

Results
Both proposed methods showed no significant difference in image quality compared to clinical images (8 [7–8.5]) down to 33% (phasrGAN 8 [6.5–8]; phasrresnet 8 [7–8], all P ≥ 0.19) phase-encoding resolution, i.e., up to three times faster image acquisition, whereas bicubic interpolation and k-space zeropadding showed significantly lower quality for 33% phase-encoding resolution (both 7 [6–8]).

Data Conclusion
Super-resolution enhancement can be used for fetal cine cardiac MRI to reduce image acquisition time while maintaining image quality. This may lead to an improved success rate for fetal cine MR imaging, as the impact of fetal motion is lessened by shortened acquisitions.

Level of Evidence
1

Technical Efficacy
Stage 2
(Less)
Please use this url to cite or link to this publication:
author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Magnetic Resonance Imaging
volume
56
issue
1
pages
223 - 231
publisher
John Wiley & Sons Inc.
external identifiers
  • scopus:85116984606
  • pmid:34652860
ISSN
1522-2586
DOI
10.1002/jmri.27956
language
English
LU publication?
yes
id
6040c3eb-925b-4ac6-8cd2-226a0d3e440a
date added to LUP
2021-10-18 11:51:06
date last changed
2023-02-27 19:04:43
@article{6040c3eb-925b-4ac6-8cd2-226a0d3e440a,
  abstract     = {{Background<br/>Fetal cardiac magnetic resonance imaging (MRI) improves the diagnosis of congenital heart defects, but is sensitive to fetal motion due to long image acquisition time. This may be overcome with faster image acquisition with low resolution, followed by image enhancement to provide clinically useful images.<br/><br/>Purpose<br/>To combine phase-encoding undersampling with super-resolution neural networks to achieve high-resolution fetal cine cardiac MR images with short acquisition time.<br/>Study Type<br/>Prospective.<br/><br/>Subjects<br/>Twenty-eight fetuses (gestational week 36 [interquartile range 33–38 weeks]).<br/><br/>Field Strength/Sequence<br/>1.5 T, balanced steady-state free precession (bSSFP) cine sequence.<br/><br/>Assessment<br/>Images were acquired using fully sampled Doppler ultrasound-gated clinical bSSFP cine as reference, with equivalent cine sequences with decreased phase-encoding resolution (25%, 33%, and 50% of clinical standard). Two super-resolution methods based on convolutional neural networks were proposed and evaluated (phasrGAN and phasrresnet). Data were partitioned into training (36 cine slices), validation (3 cine slices), and test sets (67 cine slices) without overlap. Conventional reconstruction methods using bicubic interpolation and k-space zeropadding were used for comparison. Three blinded observers scored image quality between 1 and 10.<br/><br/>Statistical Tests<br/>Image scores are reported as median [interquartile range] and were compared using Mann–Whitney's nonparametric test with P &lt; 0.05 showing statistically significant differences.<br/><br/>Results<br/>Both proposed methods showed no significant difference in image quality compared to clinical images (8 [7–8.5]) down to 33% (phasrGAN 8 [6.5–8]; phasrresnet 8 [7–8], all P ≥ 0.19) phase-encoding resolution, i.e., up to three times faster image acquisition, whereas bicubic interpolation and k-space zeropadding showed significantly lower quality for 33% phase-encoding resolution (both 7 [6–8]).<br/><br/>Data Conclusion<br/>Super-resolution enhancement can be used for fetal cine cardiac MRI to reduce image acquisition time while maintaining image quality. This may lead to an improved success rate for fetal cine MR imaging, as the impact of fetal motion is lessened by shortened acquisitions.<br/><br/>Level of Evidence<br/>1<br/><br/>Technical Efficacy<br/>Stage 2<br/>}},
  author       = {{Berggren, Klas and Ryd, Daniel and Heiberg, Einar and Aletras, Anthony and Hedström, Erik}},
  issn         = {{1522-2586}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{223--231}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Journal of Magnetic Resonance Imaging}},
  title        = {{Super-Resolution Cine Image Enhancement for Fetal Cardiac Magnetic Resonance Imaging}},
  url          = {{http://dx.doi.org/10.1002/jmri.27956}},
  doi          = {{10.1002/jmri.27956}},
  volume       = {{56}},
  year         = {{2022}},
}