Diffusion analysis with triexponential function in hepatic steatosis

Hayashi, Tatsuya; Miyati, Tosiaki; Takahashi, Junji; Tsuji, Yoshinori; Suzuki, Hidesato; Tagaya, Naomi; Hiramoto, Mariko; Fukuzawa, Kei; Tano, Masakatsu; Saitoh, Satoshi

doi:10.1007/s12194-013-0235-0

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…A faster component and a slower component for the "true" diffusion have been evaluated at high b-value. 26,27 However, in liver the signal intensities with b-values greater than 800 s/mm 2 can be close to the noise level under many clinically applicable settings. The b-value distribution in this study was based on previous studies such as that by ter Voert et al, 8 where they recommended 16 b-values for liver IVIM study.…”

Section: Discussionmentioning

confidence: 99%

Comparison of tri‐exponential decay versus bi‐exponential decay and full fitting versus segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

et al. 2019

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Objectives To determine whether bi‐ or tri‐exponential models, and full or segmented fittings, better fit the intravoxel incoherent motion (IVIM) imaging signal of healthy livers. Methods Diffusion‐weighted images were acquired with a 3 T scanner using a respiratory‐triggered echo‐planar sequence and 16 b‐values (0–800 s/mm2). Eighteen healthy volunteers had their livers scanned twice in the same session, and then once in another session. Liver parenchyma region‐of‐interest‐based measurements were processed with bi‐exponential and tri‐exponential models, with both full fitting and segmented fitting (threshold b‐value = 200 s/mm2). Results With the signal of all scans averaged, bi‐exponential model full fitting showed Dslow = 1.14 × 10−3 mm2/s, Dfast = 193.6 × 10−3 mm2/s, and perfusion fraction (PF) = 16.9%, and segmented fitting showed Dslow = 0.98 × 10−3 mm2/s, Dfast = 42.2 × 10−3 mm2/s, and PF = 23.3%. IVIM parameters derived from the tri‐exponential model were similar for full fitting and segmented fitting, with slow (D'slow = 0.98 × 10−3 mm2/s; F'slow = 76.4 or 76.6%), fast (D'fast = 15.1 or 15.4 × 10−3 mm2/s; F'fast = 11.8 or 11.7%) and very fast (D'Vfast = 445.0 or 448.8 × 10−3 mm2/s; F'Vfast = 11.8 or 11.7%) diffusion compartments. The tri‐exponential model provided an overall better fit than the bi‐exponential model. For the bi‐exponential model, full fitting provided a better fit at very low and low b‐values compared with segmented fitting, with the latter tending to underestimate Dfast; however, the segmented method demonstrated lower error in signal prediction for high b‐values. Compared with full fitting, tri‐exponential segmented fitting offered better scan‐rescan reproducibility. Conclusion For healthy liver, tri‐exponential modeling is preferred to bi‐exponential modeling. For the bi‐exponential model, segmented fitting underestimates Dfast, but offers a more accurate estimation of Dslow.

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Section: Discussionmentioning

confidence: 99%

Comparison of tri‐exponential decay versus bi‐exponential decay and full fitting versus segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

et al. 2019

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“…In addition, we did not use b-values higher than 800 s/mm 2 . A faster component and a slower component of the true diffusion have been evaluated at high b-value (22,23). However, in liver the signal intensities with b-values of more than 800 s/mm 2 may be close to the noise level under many clinically practicable scan settings.…”

Section: Discussionmentioning

confidence: 99%

Comparison of tri-exponential decay vs. bi-exponential decay and full fitting vs. segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

Chevallier¹,

Zhou²,

Cercueil³

et al. 2018

Preprint

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Purpose:To determine whether bi-or tri-exponential models, and full or segmented fittings, better fit IVIM imaging signal of healthy livers. Materials and methods:Diffusion-weighted images were acquired with a 3-T scanner using respiratory-triggered echo-planar sequence and 16 b-values (0~800 s/mm 2 ). Eighteen healthy volunteers had liver scanned twice in the same session, and then once again in another session.Region of interest (ROI)-based measurements were processed with bi-exponential model full fitting and segmented fitting (threshold b-value = 80 s/mm 2 ), as well as tri-exponential model full fitting and segmented fitting (threshold b-value = 200 s/mm 2 ). Results:With all scans' signal averaged, bi-exponential model full fitting showed D slow =1.14, D fast =193.6×10 -3 mm 2 /s, and PF=16.9%, and segmented fitting showed D slow =1.03, D fast =56.7×10 -3 mm 2 /s, and PF=21.3%. IVIM parameters derived from tri-exponential model were similar for full fitting and segmented fitting, with a slow (D' slow =0.98×10 -3 mm 2 /s; F' slow =76.4 or 76.6%), a fast (D' fast =15.1 or 15.4×10 -3 mm 2 /s; F' fast =11.8 or 11.7%) and a very fast (D' Vfast =445.0 or 448.8×10 -3 mm 2 /s; F' Vfast =11.8 or 11.7 %) diffusion compartments. Tri-exponential model provided an overall better fit than bi-exponential model. For bi-exponential model, full fitting provided better fit at very low and low b-values compared with segmented fitting with the later tended to underestimate D fast , however, segmented method demonstrated lower error in signal prediction for high b-values. Compared with full fitting, tri-exponential segmented fitting offered better scan-rescan reproducibility.Conclusion: For healthy liver, tri-exponential modelling is preferred than bi-exponential modelling. For bi-exponential model, segmented fitting underestimates D fast , but offers more accurate estimation of D slow . 4 the best fit for IVIM signal decay in the liver over the 0-800 s/mm 2 range (6). More recently, Wurnig et al. investigated an extensive DW-imaging protocol including 68 b-values and computed apparent diffusion coefficient 'spectra', and demonstrated the presence of a third component of diffusion in liver and kidney (7). However, till now tri-exponential decay model has not been studied at individual subject level with clinically applicable examination set-up. With 50 IVIM diffusion MR scans from 18 healthy volunteers, this study analyzes the fitting accuracy of biexponential vs. tri-exponential models, and full fitting vs. segmented fitting methods. Fitting residual error of predicted MR signal vs. measured MR signal with the four fitting approaches, as well as scan-rescan repeatability/reproducibility at individual subjects' level, are compared. An analysis of the error distribution in model signal prediction can offer insight into why triexponential model offers better fit than bi-exponential model for liver diffusion signal decay. The IVIM parameter physiological values associated with each fitting approach are also presented in this paper....

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“…The problem that still persists with the chosen approach is that it is not clear to which extent the chosen model of perfusion and diffusion fully describes reality, a fact that might explain the observed values of IVIM parameters in the spleen, which showed a low perfusion fraction while it is known that the spleen is a very well perfused organ. Previous studies focusing on the liver suggest that a three compartment model would be more adequate to describe perfusion and diffusion effects assessed with IVIM, with both fast and slow perfusion components found . Still to our knowledge, no study focused on the precise assessment and description of the number of compartments and different perfusion fractions present in perfused solid organs.…”

Section: Discussionmentioning

confidence: 99%

Systematic analysis of the intravoxel incoherent motion threshold separating perfusion and diffusion effects: Proposal of a standardized algorithm

Wurnig

Donati

Ulbrich

et al. 2014

Magnetic Resonance in Med

105

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Diffusion analysis with triexponential function in hepatic steatosis

Cited by 8 publications

References 35 publications

Comparison of tri‐exponential decay versus bi‐exponential decay and full fitting versus segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

Comparison of tri‐exponential decay versus bi‐exponential decay and full fitting versus segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

Comparison of tri-exponential decay vs. bi-exponential decay and full fitting vs. segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI

Systematic analysis of the intravoxel incoherent motion threshold separating perfusion and diffusion effects: Proposal of a standardized algorithm

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