PMID- 23773621
OWN - NLM
STAT- MEDLINE
DCOM- 20140221
LR  - 20211021
IS  - 1873-5894 (Electronic)
IS  - 0730-725X (Print)
IS  - 0730-725X (Linking)
VI  - 31
IP  - 7
DP  - 2013 Sep
TI  - Fast approximation to pixelwise relaxivity maps: validation in iron overloaded 
      subjects.
PG  - 1074-80
LID - S0730-725X(13)00190-2 [pii]
LID - 10.1016/j.mri.2013.05.005 [doi]
AB  - PURPOSE: Liver iron quantification by MRI has become routine. Pixelwise (PW) 
      fitting to the iron-mediated signal decay has some advantages but is slower and 
      more vulnerable to noise than region-based techniques. We present a fast, 
      pseudo-pixelwise mapping (PPWM) algorithm. MATERIALS AND METHODS: The PPWM 
      algorithm divides the entire liver into non-contiguous groups of pixels sorted by 
      rapid relative relaxivity estimates. Pixels within each group of like-relaxivity 
      were binned and fit using a Levenberg-Marquadt algorithm. RESULTS: The developed 
      algorithm worked about 30 times faster than the traditional PW approach and 
      generated R2* maps qualitatively and quantitatively similar. No systematic 
      difference was observed in median R2* values with a coefficient of variability 
      (CoV) of 2.4%. Intra-observer and inter-observer errors were also under 2.5%. 
      Small systematic differences were observed in the right tail of the R2* 
      distribution resulting in slightly lower mean R2* values (CoV of 4.2%) and 
      moderately lower SD of R2* values for the PPWM algorithm. Moreover, the PPWM 
      provided the best accuracy, giving a lower error of R2* estimates. CONCLUSION: 
      The PPWM yielded comparable reproducibility and higher accuracy than the TPWM. 
      The method is suitable for relaxivity maps in other organs and applications.
CI  - Copyright (c) 2013 Elsevier Inc. All rights reserved.
FAU - Meloni, Antonella
AU  - Meloni A
AD  - CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana and Institute of Clinical 
      Physiology, Pisa, Italy.
FAU - Zmyewski, Heather
AU  - Zmyewski H
FAU - Rienhoff, Hugh Young Jr
AU  - Rienhoff HY Jr
FAU - Jones, Amber
AU  - Jones A
FAU - Pepe, Alessia
AU  - Pepe A
FAU - Lombardi, Massimo
AU  - Lombardi M
FAU - Wood, John C
AU  - Wood JC
LA  - eng
GR  - RC1 HL099412/HL/NHLBI NIH HHS/United States
PT  - Journal Article
DEP - 20130615
PL  - Netherlands
TA  - Magn Reson Imaging
JT  - Magnetic resonance imaging
JID - 8214883
RN  - E1UOL152H7 (Iron)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Algorithms
MH  - Female
MH  - Humans
MH  - Image Processing, Computer-Assisted/methods
MH  - Iron/*chemistry
MH  - Iron Overload/*diagnosis/pathology
MH  - Liver/metabolism/*pathology
MH  - Magnetic Resonance Imaging/*methods
MH  - Male
MH  - Observer Variation
MH  - Reproducibility of Results
MH  - Young Adult
PMC - PMC3731074
MID - NIHMS494499
OTO - NOTNLM
OT  - Fast R2* mapping
OT  - Iron overload assessment
OT  - Liver
EDAT- 2013/06/19 06:00
MHDA- 2014/02/22 06:00
PMCR- 2014/09/01
CRDT- 2013/06/19 06:00
PHST- 2012/09/09 00:00 [received]
PHST- 2013/05/11 00:00 [accepted]
PHST- 2013/06/19 06:00 [entrez]
PHST- 2013/06/19 06:00 [pubmed]
PHST- 2014/02/22 06:00 [medline]
PHST- 2014/09/01 00:00 [pmc-release]
AID - S0730-725X(13)00190-2 [pii]
AID - 10.1016/j.mri.2013.05.005 [doi]
PST - ppublish
SO  - Magn Reson Imaging. 2013 Sep;31(7):1074-80. doi: 10.1016/j.mri.2013.05.005. Epub 
      2013 Jun 15.