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A multi-center inter-manufacturer study of the temporal stability of phase-contrast velocity mapping background offset errors

Gatehouse, Peter D.; Rolf, Marijn P.; Markenroth Bloch, Karin LU ; Graves, Martin J.; Kilner, Philip J.; Firmin, David N. and Hofman, Mark B. M. (2012) In Journal of Cardiovascular Magnetic Resonance 14(72).
Abstract
Background: Phase-contrast velocity images often contain a background or baseline offset error, which adds an unknown offset to the measured velocities. For accurate flow measurements, this offset must be shown negligible or corrected. Some correction techniques depend on replicating the clinical flow acquisition using a uniform stationary phantom, in order to measure the baseline offset at the region of interest and subtract it from the clinical study. Such techniques assume that the background offset is stable over the time of a patient scan, or even longer if the phantom scans are acquired later, or derived from pre-stored background correction images. There is no published evidence regarding temporal stability of the background offset.... (More)
Background: Phase-contrast velocity images often contain a background or baseline offset error, which adds an unknown offset to the measured velocities. For accurate flow measurements, this offset must be shown negligible or corrected. Some correction techniques depend on replicating the clinical flow acquisition using a uniform stationary phantom, in order to measure the baseline offset at the region of interest and subtract it from the clinical study. Such techniques assume that the background offset is stable over the time of a patient scan, or even longer if the phantom scans are acquired later, or derived from pre-stored background correction images. There is no published evidence regarding temporal stability of the background offset. Methods: This study assessed the temporal stability of the background offset on 3 different manufacturers' scanners over 8 weeks, using a retrospectively-gated phase-contrast cine acquisition with fixed parameters and at a fixed location, repeated 5 times in rapid succession each week. A significant offset was defined as 0.6 cm/s within 50 mm of isocenter, based upon an accuracy of 10% in a typical cardiac shunt measurement. Results: Over the 5 repeated cine acquisitions, temporal drift in the baseline offset was insignificant on two machines (0.3 cm/s, 0.2 cm/s), and marginally insignificant on the third machine (0.5 cm/s) due to an apparent heating effect. Over a longer timescale of 8 weeks, insignificant drift (0.4 cm/s) occurred on one, with larger drifts (0.9 cm/s, 0.6 cm/s) on the other machines. Conclusions: During a typical patient study, background drift was insignificant. Extended high gradient power scanning with work requires care to avoid drift on some machines. Over the longer term of 8 weeks, significant drift is likely, preventing accurate correction by delayed phantom corrections or derivation from pre-stored background offset data. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Magnetic resonance imaging, Phase-contrast velocity mapping, Background, velocity offset error, Cardiac output, Shunt flow, Regurgitation
in
Journal of Cardiovascular Magnetic Resonance
volume
14
issue
72
publisher
BioMed Central
external identifiers
  • wos:000311786800001
  • scopus:84867592105
ISSN
1097-6647
DOI
10.1186/1532-429X-14-72
language
English
LU publication?
yes
id
cc52cb8e-19d6-404b-8a95-99f4dc8e78cb (old id 3373320)
date added to LUP
2013-02-01 07:01:57
date last changed
2017-11-19 03:20:31
@article{cc52cb8e-19d6-404b-8a95-99f4dc8e78cb,
  abstract     = {Background: Phase-contrast velocity images often contain a background or baseline offset error, which adds an unknown offset to the measured velocities. For accurate flow measurements, this offset must be shown negligible or corrected. Some correction techniques depend on replicating the clinical flow acquisition using a uniform stationary phantom, in order to measure the baseline offset at the region of interest and subtract it from the clinical study. Such techniques assume that the background offset is stable over the time of a patient scan, or even longer if the phantom scans are acquired later, or derived from pre-stored background correction images. There is no published evidence regarding temporal stability of the background offset. Methods: This study assessed the temporal stability of the background offset on 3 different manufacturers' scanners over 8 weeks, using a retrospectively-gated phase-contrast cine acquisition with fixed parameters and at a fixed location, repeated 5 times in rapid succession each week. A significant offset was defined as 0.6 cm/s within 50 mm of isocenter, based upon an accuracy of 10% in a typical cardiac shunt measurement. Results: Over the 5 repeated cine acquisitions, temporal drift in the baseline offset was insignificant on two machines (0.3 cm/s, 0.2 cm/s), and marginally insignificant on the third machine (0.5 cm/s) due to an apparent heating effect. Over a longer timescale of 8 weeks, insignificant drift (0.4 cm/s) occurred on one, with larger drifts (0.9 cm/s, 0.6 cm/s) on the other machines. Conclusions: During a typical patient study, background drift was insignificant. Extended high gradient power scanning with work requires care to avoid drift on some machines. Over the longer term of 8 weeks, significant drift is likely, preventing accurate correction by delayed phantom corrections or derivation from pre-stored background offset data.},
  author       = {Gatehouse, Peter D. and Rolf, Marijn P. and Markenroth Bloch, Karin and Graves, Martin J. and Kilner, Philip J. and Firmin, David N. and Hofman, Mark B. M.},
  issn         = {1097-6647},
  keyword      = {Magnetic resonance imaging,Phase-contrast velocity mapping,Background,velocity offset error,Cardiac output,Shunt flow,Regurgitation},
  language     = {eng},
  number       = {72},
  publisher    = {BioMed Central},
  series       = {Journal of Cardiovascular Magnetic Resonance},
  title        = {A multi-center inter-manufacturer study of the temporal stability of phase-contrast velocity mapping background offset errors},
  url          = {http://dx.doi.org/10.1186/1532-429X-14-72},
  volume       = {14},
  year         = {2012},
}