A comparison of fitting algorithms for diffusion-weighted MRI data analysis using an intravoxel incoherent motion model.
OBJECTIVE
The objective of this study is to propose a modified VARiable PROjection (VARPRO) algorithm specifically tailored for fitting the intravoxel incoherent motion (IVIM) model to diffusion-weighted magnetic resonance imaging (DW-MRI) data from locally advanced rectal cancer (LARC).


METHODS
The proposed algorithm is compared with classical non-linear least squares (NLLS) analysis using the Levenberg-Marquardt (LM) algorithm and with two recently proposed algorithms for 'segmented' analysis. These latter two comprise two consecutive steps: first, a subset of parameters is estimated using a portion of data; second, the remaining parameters are estimated using the whole data and the previous estimates. The comparison between the algorithms was based on the [Formula: see text] goodness-of-fit measure: performance analysis was carried out on real data obtained by DW-MRI on 40 LARC patients.


RESULTS
The performance of the proposed algorithm was higher than that of LM in 64 % of cases; 'segmented' methods were poorer than our algorithm in 100 % of cases.


CONCLUSIONS
The proposed modified VARPRO algorithm can lead to better fit of the IVIM model to LARC DW-MRI data compared to other techniques.
Radiology Unit, Department of Diagnostic Imaging Radiant and Metabolic Therapy, Istituto Nazionale Tumori Fondazione Giovanni Pascale RCCS, Via Mariano Semmola, 80131, Naples, Italy.
Roberta
R
Fusco
Department of Electrical Engineering and Information Technologies, University 'Federico II' of Naples, Via Claudio, 21, Naples, Italy. msansone@unina.it.
Mario
http://orcid.org/0000-0003-3556-7771
M
Sansone
Radiology Unit, Department of Diagnostic Imaging Radiant and Metabolic Therapy, Istituto Nazionale Tumori Fondazione Giovanni Pascale RCCS, Via Mariano Semmola, 80131, Naples, Italy.
Antonella
A
Petrillo
D000328:Adult; D000368:Aged; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016018:Least-Squares Analysis; D008875:Middle Aged; D008962:Models, Theoretical; D009038:Motion; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results
Diffusion weighted magnetic resonance imaging (DW-MRI); Intravoxel incoherent motion (IVIM); Locally advanced rectal cancer (LARC); Non-linear least squares (NLLS); Rectal neoplasms
Radiology. 1988 Aug;168(2):497-505
3393671
Magn Reson Med. 2014 Jan;71(1):411-20
23408505
Magn Reson Med. 2015 Oct;74(4):1077-85
25302780
Magn Reson Med. 2012 Jan;67(1):89-97
21702062
J Magn Reson Imaging. 2015 Aug;42(2):362-70
25407944
Invest Radiol. 2014 Feb;49(2):93-100
24089021
Radiology. 2008 Dec;249(3):748-52
19011179
MAGMA. 2015 Aug;28(4):377-83
25475914
Abdom Imaging. 2001 Mar-Apr;26(2):161-5
11178693
J Magn Reson Imaging. 2014 Oct;40(4):813-23
24273096
AJNR Am J Neuroradiol. 2004 Sep;25(8):1331-6
15466327
Eur J Radiol. 2013 Dec;82(12):e782-9
24034833