Evaluation of fibrosis and inflammation in diffuse liver diseases using intravoxel incoherent motion diffusion-weighted MR imaging

Abstract

Purpose: The purpose of the study was to evaluate the role of intravoxel incoherent motion (IVIM) diffusion model for the assessment of liver fibrosis and inflammation in diffuse liver disorders, also considering the presence of liver steatosis and iron deposits. Methods: Seventy-four patients were included, with liver biopsy and a 3 Tesla abdominal magnetic resonance imaging examination, with an IVIM diffusion-weighted sequence (single-shot spin-echo echo-planar sequence, with gradient reversal fat suppression; 6 b-values: 0, 50, 200, 400, 600, and 800 s/mm 2 ). Histological evaluation comprised the Ishak modified scale, for grading inflammation and fibrosis, plus steatosis and iron loading classification. The liver apparent diffusion coefficient (ADC) and IVIM parameters (D, D*, f) were calculated from the IVIM images. The relationship between IVIM parameters and histopathological scores were evaluated by ANOVA and Spearman correlation tests. A testretest experiment assessed reproducibility and repeatability in 10 healthy volunteers and 10 randomly selected patient studies. Results: ADC and f values were lower with higher fibrosis stages (p = 0.009, p = 0.006, respectively) and also with higher necro-inflammatory activity grades (p = 0.02, p = 0.017, respectively). Considered together, only fibrosis presented a significant effect on ADC and f measurements (p < 0.05), whereas inflammation had no significant effect (p > 0.05). A mild correlation was found between ADC and f with fibrosis (R S = -0.32 and R S = -0.38; p < 0.05) and inflammation (R S = -0.31 and R S = -0.32, p < 0.05; respectively). The AUROC for ADC and f measurements with the different dichotomizations between fibrosis or inflammation grades were only fair (0.670 to 0.749, p < 0.05). Neither D nor D* values were significantly different between liver fibrosis or inflammation grades. D measurements were significantly different across histologic grades of steatosis (p < 0.001) and iron overload (p < 0.001), whereas f measurements showed significant differences across histologic steatosis grades (p = 0.005).

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).…”

“…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.…”

Dual‐frequency MR elastography to differentiate between inflammation and fibrosis of the liver: Comparison with histopathology

“…Third, comparison between MRE and quantitative diffusion‐weighted images could not be achieved in this study. Intravoxel incoherent motion diffusion would be another way to estimate inflammation of the liver, which warrants further investigation . Finally, the scanning parameter for the 80‐Hz vibration frequency was not optimized.…”

“…Intravoxel incoherent motion diffusion would be another way to estimate inflammation of the liver, which warrants further investigation. 27,33 Finally, the scanning parameter for the 80-Hz vibration frequency was not optimized. The scanning parameter in the present study was decided based on an automatic setting as the optimized values at our 1.5T MR unit, resulting from synchronization between bipolar motion-encoding gradients and vibration frequencies.…”

Liver MRI: From basic protocol to advanced techniques

“…However, ADC and IVIM measurements are not accurate enough to be used in clinical practice for staging liver fibrosis, in diffuse liver diseases [60]. Also, its use has been limited by the large variability in the cut-off values and by the possible confounding effect of hepatic steatosis [60,61] or iron overload [61].…”