Intravoxel incoherent motion diffusion-weighted imaging in the liver: comparison of mono-, bi- and tri-exponential modelling at 3.0-T

Abstract

• For normal liver, tri-exponential IVIM model might be superior to bi-exponential • A very fast compartment (D = 404.00 ± 43.7 × 10 (-3) mm (2) /s; f = 13.5 ± 0.8 %) is determined from the tri-exponential model • The compartment contributes to the IVIM signal only for b ≤ 15 s/mm(2).

Advanced diffusion models in head and neck squamous cell carcinoma patients: Goodness of fit, relationships among diffusion parameters and comparison with dynamic contrast-enhanced perfusion

“…tri-exponential function [23]. In addition, increasing data points in large b-values can influence the tissue diffusion coefficient, the kurtosis value obtained by DKI, and the α value obtained by the SEM.…”

Liver intravoxel incoherent motion (IVIM) magnetic resonance imaging: a comprehensive review of published data on normal values and applications for fibrosis and tumor evaluation

“…Various fitting algorithms have been used to determine IVIM parameters, including asymptotic fitting (9)(10)(11)(12)(19)(20)(21)24,41,45,46,48,51,53), nonlinear least square (usually Levenberg-Marquardt) fitting (23,42,47,52,54,55), and Bayesian fitting (15,22,40,43,50). Current review cannot draw conclusion which one is better than others, nor can the mean values be compared (Figure 8).…”

“…Different from asymptotic fitting that optimizes the measurement of Dslow, it gives an identical weight to each variable. However, it has been reported that leastsquares fitting has less stability compared to asymptotic fitting since it is sensitive to data outliers and image noise (38,48,53).…”

“…Accumulation of collagen deposits and activated stellate cells contribute to increased hepatic resistance to portal blood flow, development of portal hypertension, and reduced portal blood perfusion. The decrease of blood perfusion can arise from a number of concomitant alterations in the tissue microenvironment, including collagen deposition, fatty (9)(10)(11)15,23,24,42,43,45,46,(48)(49)(50)(51)(53)(54)(55), free-breathing (FB) (19)(20)(21)40,41,47), and breath-hold (BH) (44). Solid line represents the median value of each group.…”

Depiction of the perfusion components’ volume fraction distribution in generalized intravoxel incoherent motion by using Gaussian mixture model

“…In 1988, Le Bihan et al 1 proved that, besides the water diffusion, a fast diffusion component existed in the brain. To deal with these problems, some other multiexponential IVIM models, such as the triexponential IVIM model 16 and the five-compartmental microcirculatory model, 17 were proposed by adding a number of perfusion components. In 1992, Neil et al 14 detected the multiexponential decay in 19F NMR experiments.…”