Hepatic Apparent Diffusion Coefficient Research Articles

Correlation analysis of dynamic changes of abdominal fat during rapid weight loss after bariatric surgery: A prospective magnetic resonance imaging study

ObjectiveThe factors related to the changes in the liver and abdominal adipose tissue during the rapid weight loss after bariatric surgery remain uncertain. MethodsThis study included 44 participants who had undergone sleeve gastrectomy. The study aimed to analyze changes and correlations of body weight (BW), laboratory tests, and magnetic resonance imaging (MRI) indicators of the liver and abdominal adipose tissue conducted before and after bariatric surgery at 1, 3, and 6 months. ResultsFollowing a rapid weight loss within 6 months of surgery, there was a concurrent decrease in blood glucose, blood lipids, and fat content of the liver and abdomen and the changes showed a correlation. The change of BW (ΔBW) was positively correlated with the change of hepatic proton density fat fraction (ΔPDFF) in one and three months after surgery and was positively correlated with the change of abdominal visceral fat area (ΔAVFA) in six months after surgery, (P<0.05). In one month after surgery, ΔPDFF was positively correlated with the change of aspartate aminotransferase (ΔAST), change of alanine aminotransferase (ΔALT), and change of triglyceride glucose (ΔTYG) index (P<0.05). ΔPDFF was positively correlated with the change of hepatic native T1 values (P<0.001) and was moderately negatively correlated with the change of hepatic apparent diffusion coefficient (ΔADC) values in three months after surgery (P<0.05). ConclusionΔBW can serve as an indirect indicator for evaluating changes in liver fat fraction at 1 and 3 months after bariatric surgery and indicative of changes in visceral fat 6 months after surgery. ΔPDFF was positively correlated with ΔAST, ΔALT and ΔTYG index in 1 months after surgery.

Usefulness of Diffusion-Weighted Imaging in Evaluating Acute Cellular Rejection and Monitoring Treatment Response in Liver Transplant Recipients.

Acute cellular rejection (ACR) is a significant immune issue among recipients following liver transplantation. Although diffusion-weighted magnetic resonance imaging (DWI) is widely used for diagnosing liver disease, it has not yet been utilized for monitoring ACR in patients after liver transplantation. Therefore, the aim of this study was to evaluate the efficacy of DWI in monitoring treatment response among recipients with ACR. This study enrolled 25 recipients with highly suspected ACR rejection, and all subjects underwent both biochemistry and DWI scans before and after treatment. A pathological biopsy was performed 4 to 24 h after the first MRI examination to confirm ACR and degree of rejection. All patients were followed up and underwent a repeated MRI scan when their liver function returned to the normal range. After data acquisition, the DWI data were post-processed to obtain the apparent diffusion coefficient (ADC) map on a voxel-by-voxel basis. Five regions of interest were identified on the liver parenchyma to measure the mean ADC values from each patient. Finally, the mean ADC values and biochemical markers were statistically compared between ACR and non-ACR groups. A receiver operating characteristic (ROC) curve was constructed to evaluate the performance of the ADC and biochemical data in detecting ACR, and correlation analysis was used to understand the relationship between the ADC values, biochemical markers, and the degree of rejection. The histopathologic results revealed that 20 recipients had ACR, including 10 mild, 9 moderate, and 1 severe rejection. The results demonstrated that the ACR patients had significantly lower hepatic ADC values than those in patients without ACR. After treatment, the hepatic ADC values in ACR patients significantly increased to levels similar to those in non-ACR patients with treatment. The ROC analysis showed that the sensitivity and specificity for detecting ACR were 80% and 95%, respectively. Furthermore, the correlation analysis revealed that the mean ADC value and alanine aminotransferase level had strong and moderate negative correlation with the degree of rejection, respectively (r = -0.72 and -0.47). The ADC values were useful for detecting hepatic ACR and monitoring treatment response after immunosuppressive therapy.

The utility of apparent diffusion coefficient values in predicting liver fibrosis in chronic hepatitis B

Aim: We aimed to determine the relationship between apparent diffusion coefficient (ADC) values obtained from diffusion-weighted images, histopathological fibrosis, and activity stages in patients with chronic hepatitis B infection. &#x0D; Material and Method: A total of 30 patients with chronic hepatitis B admitted to our hospital between September 2012 and June 2014 were included in the study. All patients underwent biopsy and abdomen MRI examination before the treatment. Diffusion examinations at five different b-values (50, 300, 500, 700, and 1000 s/mm2) were added to the abdominal MRI examination. &#x0D; Results: The hepatic ADC values at all b-values were negatively correlated with fibrosis stages (p

Diffusion tensor magnetic resonance imaging in the grading of liver fibrosis associated with congenital ductal plate malformations.

Liver biopsy is still the standard method for the diagnosis of ductal plate malformations (DPM). However, it is an invasive tool. Magnetic resonance imaging (MRI) has shown its accuracy in the diagnosis of this pathology. Herein, a study was conducted to elucidate the role of diffusion MRI parameters in predicting the degree of hepatic fibrosis. This prospective study included 29 patients with DPM and 20 healthy controls. Both groups underwent diffusion tensor magnetic resonance imaging (DT-MRI), and its parameters were compared between patients and controls, and then they were correlated with the degree of liver fibrosis in the patient group. All patients with DPM, whatever its type, expressed a significantly lower hepatic apparent diffusion coefficient (ADC) compared to controls. However, fractional anisotropy (FA) showed no significant difference between them. The ADC value of 1.65 × 10-3 mm2/s had sensitivity and specificity of 82.1% and 90%, respectively, in differentiating DPM patients from healthy controls. It was evident that patients with higher fibrosis grades had significantly lower hepatic ADC, indicating a negative correlation between ADC and the grade of hepatic fibrosis; rs = -0.901, p < 0.001. DT-MRI showed good efficacy in the diagnosis of congenital DPM. Moreover, ADC could be applied to monitor the degree of liver fibrosis rather than the invasive liver biopsy. No significant correlation was noted between the FA and the grades of liver fibrosis.

The Benefit of Apparent Diffusion Coefficient in Evaluating the Invasiveness of Hepatocellular Carcinoma.

BackgroundThis study aimed to evaluate hepatocellular carcinoma (HCC) invasiveness using the apparent diffusion coefficient (ADC).MethodsEighty-one patients with HCC confirmed by pathology and examined by preoperative magnetic resonance imaging diffusion-weighted imaging from January 2015 to September 2020 were retrospectively analyzed. Clinical and pathological data were recorded. The minimum ADC (ADCmin), average ADC (ADCmean), and the ratio of ADCmean to normal-appearing hepatic parenchyma ADC (ADCnahp) were assessed. The associations between clinical information, ADC value, and HCC invasiveness (microvascular invasion [MVI], tumor differentiation, and Ki-67 expression) were evaluated statistically. Independent risk factors related to HCC invasiveness were screened using binary logistic regression, and the diagnostic efficiency was evaluated by the receiver operating characteristic curve and its area under the curve (AUC) value.ResultsTumor size was related to HCC MVI and tumor differentiation (P < 0.05). HCC MVI was associated with ADCmin, ADCmean, and the ADCmean-to-ADCnahp ratio (all P < 0.05) with AUC values of 0.860, 0.860, and 0.909, respectively. If these were combined with tumor size, the AUC value increased to 0.912. The degree of tumor differentiation was associated with ADCmin, ADCmean, and the ADCmean-to-ADCnahp ratio (all P < 0.05) with AUC values of 0.719, 0.708, and 0.797, respectively. If these were combined with tumor size, the AUC value increased to 0.868. Ki-67 expression was associated with ADCmin, ADCmean, and the ADCmean-to-ADCnahp ratio (all P < 0.05) with AUC values of 0.731, 0.747, and 0.746, respectively. Combined them, the AUC value increased to 0.763.ConclusionsThe findings indicated that the ADC value has significant potential for the non-invasive preoperative evaluation of HCC invasiveness.

Alkolün Karaciğer Görünür Difüzyon Katsayısı Değerleri Üzerine Etkileri: Tek Merkez Çalışması

Background and Aims: This study aimed to investigate the relationship between liver apparent diffusion coefficient values and potential early-stage liver injury by comparing apparent diffusion coefficient values obtained by liver diffusion-weighted magnetic resonance imaging between individuals with a history of excessive alcohol consumption and healthy volunteers. Materials and Methods: This study enrolled 35 individuals with a history of excessive alcohol consumption and 32 healthy volunteers. In all cases, blood samples were taken to measure biochemical parameters and complete blood count. Upper abdominal magnetic resonance imaging including liver diffusion-weighted imaging was performed. Results: In total, 19 individuals with a history of excessive alcohol consumption and 20 healthy volunteers were included in the study. The mean apparent diffusion coefficient values obtained by high b value (b 1000) diffusion-weighted imaging in individuals with a history of excessive alcohol consumption were lower than those in healthy volunteers. Although no significant difference was observed between the two groups in terms of biochemical parameters, hepatic apparent diffusion coefficient values in both groups were positively correlated with international normalized ratio values and negatively correlated with gamma-glutamyl transferase and alkaline phosphatase levels (r = 0.002, r = −0.007, r = −0.049, respectively). Conclusion: Diffusion-weighted imaging is a noninvasive imaging technique that can be used for the detection and follow-up of liver fibrosis induced by alcohol consumption.

Evaluation of the changes in hepatic apparent diffusion coefficient and hepatic fat fraction in healthy cats during body weight gain.

To determine the change in mean hepatic apparent diffusion coefficient (ADC) and hepatic fat fraction (HFF) during body weight gain in cats by use of MRI. 12 purpose-bred adult neutered male cats. The cats underwent general health and MRI examination at time 0 (before dietary intervention) and time 1 (after 40 weeks of being fed high-energy food ad libitum). Sequences included multiple-echo gradient-recalled echo MRI and diffusion-weighted MRI with 3 b values (0, 400, and 800 s/mm2). Variables (body weight and the HFF and ADC in selected regions of interest in the liver parenchyma) were compared between time points by Wilcoxon paired-sample tests. Relationships among variables were assessed with generalized mixed-effects models. Median body weight was 4.5 and 6.5 kg, mean ± SD HFF was 3.39 ± 0.89% and 5.37 ± 1.92%, and mean ± SD hepatic ADC was 1.21 ± 0.08 × 10-3 mm2/s and 1.01 ± 0.2 × 10-3 mm2/s at times 0 and 1, respectively. Significant differences between time points were found for body weight, HFF, and ADC. The HFF was positively associated with body weight and ADC was negatively associated with HFF. Similar to findings in people, cats had decreasing hepatic ADC as HFF increased. Protons associated with fat tissue in the liver may reduce diffusivity, resulting in a lower ADC than in liver with lower HFF. Longer studies and evaluation of cats with different nutritional states are necessary to further investigate these findings.

Diffusion-Weighted Imaging for Differentiation of Biliary Atresia and Grading of Hepatic Fibrosis in Infants with Cholestasis.

ObjectiveTo determine whether the values of hepatic apparent diffusion coefficient (ADC) can differentiate biliary atresia (BA) from non-BA or be correlated with the grade of hepatic fibrosis in infants with cholestasis.Materials and MethodsThis retrospective cohort study included infants who received liver MRI examinations to evaluate cholestasis from July 2009 to October 2017. Liver ADC, ADC ratio of liver/spleen, aspartate aminotransferase to platelet ratio index (APRI), and spleen size were compared between the BA and non-BA groups. The diagnostic performances of all parameters for significant fibrosis (F3–4) were obtained by receiver-operating characteristics (ROCs) curve analysis.ResultsAltogether, 227 infants (98 males and 129 females, mean age = 57.2 ± 36.3 days) including 125 BA patients were analyzed. The absolute ADC difference between two reviewers was 0.10 mm2/s for both liver and spleen. Liver ADC value was specific (80.4%) and ADC ratio was sensitive (88.0%) for the diagnosis of BA with comparable performance. There were 33 patients with F0, 15 with F1, 71 with F2, 35 with F3, and 11 with F4. All four parameters of APRI (τ = 0.296), spleen size (τ = 0.312), liver ADC (τ = −0.206), and ADC ratio (τ = −0.288) showed significant correlation with fibrosis grade (all, p < 0.001). The cutoff values for significant fibrosis (F3–4) were 0.783 for APRI (area under the ROC curve [AUC], 0.721), 5.9 cm for spleen size (AUC, 0.719), 1.044 × 10−3 mm2/s for liver ADC (AUC, 0.673), and 1.22 for ADC ratio (AUC, 0.651).ConclusionLiver ADC values and ADC ratio of liver/spleen showed limited additional diagnostic performance for differentiating BA from non-BA and predicting significant hepatic fibrosis in infants with cholestasis.

Combination of hepatocyte fraction and diffusion-weighted imaging as a predictor in quantitative hepatic fibrosis evaluation.

To investigate the performance of the combined hepatocyte fraction (HepF) and apparent diffusion coefficient (ADC) values to stage hepatic fibrosis (HF) in patients with hepatitis B/C. A total of 281 patients with hepatitis B/C prospectively underwent gadoxetate disodium-based T1 mapping and diffusion-weighted imaging. HepF was determined from pre and postcontrast T1 mapping with pharmacokinetics. The independent predictors of the HF stage (S0-4) were identified from HepF, ADC, conventional T1-based parameters, and age using a logistic regression analysis. The performances of independent and combined predictors in diagnosing various HF stages were compared by analyzing receiver operating characteristic curves. The intraclass correlation coefficient (ICC) was used to assess the interobserver reproducibility of each predictor. In total, 167 patients with various stages of HF were included. All measurements had excellent interobserver agreement (ICC ≥ 0.75). The hepatic relative enhancement, HepF ,and ADC values were significantly different among various HF stages (p < 0.05). The HepF and ADC were independent predictors of > S0, > S1, > S2 , and > S3 disease (p < 0.05). T1Liver, T1Spleen, and T1Liver/Spleen were independent predictors of S > 2 disease (p < 0.05). The performance of HepF combined with the ADC (area under the curve (AUC) = 0.84-0.95) was higher than HepF (AUC = 0.79-0.92) or ADC (AUC = 0.82-0.89) alone in diagnosing > S0, > S1, > S2 , and > S3 disease. The combined predictor of HepF and ADC shows acceptable performance for staging HF.

Clinical utility of mono-exponential model diffusion weighted imaging using two b-values compared to the bi- or stretched exponential model for the diagnosis of biliary atresia in infant liver MRI.

To investigate the clinical utility of mono-exponential model diffusion weighted imaging (DWI) using two b-values compared to the bi- or stretched exponential model to differentiate biliary atresia (BA) from non-BA in pediatric liver magnetic resonance imaging (MRI). Patients who underwent liver MRI with DWI for suspected BA from November 2017 to September 2018 were retrospectively included and divided into BA and non-BA groups. Laboratory results including γ-glutamyl transferase (γGT) were compared between the two groups using the Mann-Whitney U test and Fisher's exact test. The hepatic apparent diffusion coefficient (ADC) 10 using ten b-values and ADC 2 using two b-values were obtained from the mono-exponential model. The slow diffusion coefficient (D), fast diffusion coefficient (D*), and perfusion fraction (f) were obtained from the bi-exponential model. The distributed diffusion coefficient (DDC) and heterogeneity index (α) were measured from the stretched exponential model. Parameters were compared between the two groups using a linear mixed model and diagnostic performance was assessed using the area under the curve (AUC) analysis. For 12 patients in the BA and five patients in the non-BA group, the ADC 10 (median 0.985 ×10-3 mm2/s vs. 1.332 ×10-3 mm2/s, p = 0.008), ADC 2 (median 0.987 ×10-3 mm2/s vs. 1.335 ×10-3 mm2/s, p = 0.017), D* (median 33.2 ×10-3 mm2/s vs. 55.3 ×10-3 mm2/s, p = 0.021), f (median 13.4%, vs. 22.1%, p = 0.009), and DDC (median 0.889 ×10-3 mm2/s vs. 1.323 ×10-3 mm2/s, p = 0.009) values were lower and the γGT (median 368.0 IU/L vs. 93.5 IU/L, p = 0.02) and α (median 0.699 vs. 0.556, p = 0.023) values were higher in the BA group. The AUC values for γGT (AUC 0.867 95% confidence interval [CI] 0.616-0.984), ADC 10 (AUC 0.963, 95% CI 0.834-0.998), ADC 2 (AUC 0.925, 95% CI 0.781-0.987), f (AUC 0.850, 95% CI 0.686-0.949), and DDC (AUC 0.925, 95% CI 0.781-0.987) were not significantly different, except for the D* and α values. Patients with BA had lower ADC 10, ADC 2, D*, f, and DDC values and higher γGT and α values than those in the non-BA group. The diagnostic performance of ADC 2 using only two b-values showed excellent diagnostic performance and was not significantly different from that of γGT, ADC 10, f, and DDC for diagnosing BA.

Assessment of diagnostic value of DWI technique in the evaluation of liver fibrosis

Introduction: The liver fibrosis is caused by extracellular accumulation of cluster, glycos amino glycans and proteoglycans, which this extracellular accumulation may limit the penetration and molecular movement of water in the tissue, so the Diffusion weighted imaging(DWI) technique is due to the sensitivity to the movement and release of water molecules Can show this restriction. Using this technique, in addition to examining the entire liver, sections of the liver tissue most affected by fibrosis can also be identified. The purpose of this study was to evaluate the use of apparent diffusion coefficient (ADC) measurement in DWI imaging technique and to investigate the correlation between this method and the method of sampling in patients. Materials and Methods: Twenty-five chronic viral hepatitis C patients were examined by 1.5 Tesla MR scanner with diffusion gradient encoding in three orthogonal directions at b-values of (200, 500, 700, and 1000 s/mm2). They were correlated to biopsy finding and graded according to Ishak scoring system. Hepatic ADC values were measured for patients. Results: The best correlation between ADC values and biopsy were seen at b-values 200, 700, and 1000 s/mm2. lesser correlation was obtained at b-values of 500 s/mm2. Cut off values between different grades of fibrosis were calculated and presented in the text. Conclusion: ADC measured with DWI is a reliable non-invasive technique for quantification of liver fibrosis, and could replace liver biopsy in certain cases.

Development of a novel rat model of heterogeneous hepatic injury by injection with colchicine via the splenic vein.

AIMTo develop a novel rat model of heterogeneous hepatic injury.METHODSSeventy male Sprague-Dawley rats were randomly divided into a control group (n = 10) and a colchicine group (n = 60). A 0.25% colchicine solution (0.4 mL/kg) was injected via the splenic vein in the colchicine group to develop a rat model of heterogeneous hepatic injury. An equal volume of normal saline was injected via the splenic vein in the control group. At days 3, 7, and 14 and weeks 4, 8, and 12 after the operation, at least seven rats of the colchicine group were selected randomly for magnetic resonance imaging (MRI) examinations, and then they were euthanized. Ten rats of the control group underwent MRI examinations at the same time points, and then were euthanized at week 12. T2-weighted images (T2WI) and diffusion weighted imaging (DWI) were used to evaluate the heterogeneous hepatic injury. The heterogeneous injury between the left and right hepatic lobes was assessed on liver sections according to the histological scoring criteria, and correlated with the results of MRI study.RESULTSObvious pathological changes occurred in the hepatic parenchyma in the colchicine group. Hepatic injury scores were significantly different between the left and right lobes at each time point (P < 0.05). There was a significant difference in apparent diffusion coefficient (ADC) of DWI and liver-to-muscle ratio (LMR) of T2WI between the left and right lobes of rats in the colchicine group (P < 0.05) at each time point, and similar results were observed between the colchicine and control groups. Besides, there was a significant correlation between hepatic injury scores and ADC values or LMR (r = -0.682, P = 0.000; r = -0.245, P = 0.018).CONCLUSIONInjection with colchicine via the splenic vein can be used to successfully develop a rat model of heterogeneous hepatic injury. DWI and T2WI may help evaluate the heterogeneous injury among liver lobes.

3.0T intravoxel incoherent motion magnetic resonance imaging evaluation for the hepatic warm-ischemia injury in a rabbit model

Objective To investigate the feasibility and diagnostic efficacy of 3.0T intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the evaluation of hepatic warm ischemia-reperfusion injury (WIRI) in a rabbit model. Methods Fifty healthy, adult, male New Zealand white rabbits were randomly divided into sham-operation group (n=10) and four test groups (each n=10), which depended on different warm ischemia time (ie, 10, 20, 30, and 40 min group). Hepatic WIRI was induced by occluding hepatic inflow for different minute and reperfusion for 6 hours. Traditional MRI and IVIM were performed on a 3.0T clinical magnetic resonance (MR) scanner, four diffusion parameters, that is apparent diffusion coefficient (ADC), true diffusion (Dslow), pseudodiffusion (Dfast) and perfusion fraction (PF), were calculated from IVIM image. Rabbits were sacrificed for biochemical and histomorphological analysis after MR scanning, which including alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) of serum, and malondialdehyde (MDA), superoxide dismutase (SOD) and myeloperoxidase (MPO) of liver tissue. Statistical analysis was performed using one-way analysis of variance (ANOVA) or non-parametric test for multiple group comparisons of the IVIM parameters and biochemical parameters. The Pearson’s or Spearman’s correlation coefficient was calculated to assess the correlations between IVIM parameters and biochemical parameters. Receiver operating characteristic (ROC) curves were used to determine the diagnostic accuracy of IVIM parameters for predicting the hepatic WIRI. Results Compared with the sham group, the hepatic ADC, Dslow, Dfast, and PF were reduced in the test groups. Meanwhile, the values of IVIM parameters gradually decreased as prolonged warm ischemia time (ADC was 1.36±0.15, 1.28±0.07, 1.10±0.13, 1.10±0.15 and 0.98±0.18, Dslow was 1.29±0.14, 1.24±0.07, 1.08±0.11, 1.03±0.18 and 0.94±0.15, Dfast was 31.33±6.44, 25.53±2.10, 24.90±1.84, 23.00±1.59 and 23.76±1.41, PF was 30.44±2.80, 26.26±4.41, 24.50±2.24, 19.97±3.39 and 17.42±3.25, respectively) (P=0.005). IVIM parameters corresponded well with biochemical parameters (P=0.005). The area under curve (AUC) of ADC, Dslow, Dfast, and PF was 0.876, 0.824, 0.897 and 0.937, respectively. Histopathological analysis showed hepatocyte edema, inflammatory cell infiltration, sinusoids and central vein congestion, and different levels of fibrous tissue proliferation in the test groups. Conclusion 3.0T IVIM imaging is a noninvasive and quantitative technique in assessing the hepatic WIRI in a rabbit model, which implies its further application for dynamic monitoring of hepatic WIRI, and preclinical assessment of new pharmaceutics. Key words: Hepatic warm ischemia-reperfusion injury; Diffusion weighted imaging; Intravoxel incoherent motion; Magnetic resonance imaging

Postmortem MR diffusion-weighted imaging of the liver: time-behavior of the hepatic apparent diffusion coefficient in the early death interval.

The objective of this study is to assess postmortem changes of the hepatic apparent diffusion coefficient (ADC) at multiple time points in the time interval of 16hours postmortem in comparison to in vivo controls and to literature data. Hepatic diffusion-weighted imaging (DWI) was repeatedly performed at 1.5Tesla (b values 50, 400, and 800s/mm2) in 2-hourly steps within 16hours postmortem in 19 cases (male to female 13:6, mean age 68.5±12.2years) and 5 in vivo controls. The core body temperature was measured rectally prior to every scan. Mean ADC values were calculated from regions of interest (ROIs) and compared to in vivo healthy controls and to literature data of normal liver parenchyma. Spearman rank correlation and Levenberg-Marquardt algorithm were used to assess a relationship between postmortem core body temperature and ADC values. Mean hepatic ADC values were significantly lower in postmortem cases than in in vivo controls (52.0±15.0·10-5mm2/s vs. 111.0±15.7·10-5mm2/s, p<0.0001). The ex vivo liver ADC correlated inversely to calculated liver temperature (-3.5±0.8)·10-5mm2/s/°C, r=-0.44, p<0.0001. At low calculated liver temperature (<30°C), the ADC described an average increase of (22±10)·10-5mm2/s/°C. Hepatic ADC values show a characteristic change in the immediate 16hours postmortem, which is influenced by the postmortem liver temperature change. With the knowledge of characteristic postmortem liver changes, diffusion-weighted imaging could be added to conventional postmortem MRI for virtual autopsy.

Apparent diffusion coefficient normalization of normal liver: Will it improve the reproducibility of diffusion-weighted imaging at different MR scanners as a new biomarker?

Apparent diffusion coefficient (ADC) measurement in diffusion-weighted imaging (DWI) has been reported to be a helpful biomarker for detection and characterization of lesion. In view of the importance of ADC measurement reproducibility, the aim of this study was to probe the variability of the healthy hepatic ADC values measured at 3 MR scanners from different vendors and with different field strengths, and to investigate the reproducibility of normalized ADC (nADC) value with the spleen as the reference organ. Thirty enrolled healthy volunteers received DWI with GE 1.5T, Siemens 1.5T, and Philips 3.0T magnetic resonance (MR) systems on liver and spleen (session 1) and were imaged again after 10 to 14 days using only GE 1.5T MR and Philips 3.0T MR systems (session 2). Interscan agreement and reproducibility of ADC measurements of liver and the calculated nADC values (ADCliver/ADCspleen) were statistically evaluated between 2 sessions. In session 1, ADC and nADC values of liver were evaluated for the scanner-related variability by 2-way analysis of variance and intraclass correlation coefficients (ICCs). Coefficients of variation (CVs) of ADCs and nADCs of liver were calculated for both 1.5 and 3.0-T MR system. Interscan agreement and reproducibility of ADC measurements of liver and related nADCs between 2 sessions were found to be satisfactory with ICC values of 0.773 to 0.905. In session 1, the liver nADCs obtained from different scanners were consistent (P = 0.112) without any significant difference in multiple comparison (P = 0.117 to >0.99) by using 2-way analysis of variance with post-hoc analysis of Bonferroni method, although the liver ADCs varied significantly (P < 0.001). nADCs measured by 3 scanners were in good interscanner agreements with ICCs of 0.685 to 0.776. The mean CV of nADCs of both 1.5T MR scanners (9.6%) was similar to that of 3.0T MR scanner (8.9%). ADCs measured at 3 MR scanners with different field strengths and vendors could not be compared directly. Normalization of ADCs, however, may provide better reproducibility by overcoming these potential issues.

Assessment of the liver and spleen in children with Gaucher disease type I with diffusion-weighted MR imaging

PurposeTo assess hepatic and splenic apparent diffusion coefficient (ADC) in children with Gaucher disease type I with diffusion-weighted MR imaging and to correlate hepatic and splenic ADC with parameters of disease severity. Subjects and methodsProspective study was conducted upon 25 children (11 treated and 14 untreated) with Gaucher disease and 12 age and sex matched control children. They underwent diffusion-weighted MR imaging of abdomen. Hepatic and splenic ADC and volume were calculated. ResultsThere was statistically difference in hepatic and splenic apparent diffusion coefficient (P=0.001) between patients and controls. The cutoff ADC of liver and spleen used to differentiate patients from controls were 0.47 and 0.39×10−3mm2 with area and curve of 0.947 and 0.886 respectively. There was significant difference in hepatic and splenic ADC between untreated and treated patients (P=0.003 and 0.001). Hepatic ADC correlated with splenic volume (r=−0.721), hepatic volume (r=−0.555) and chitotriosidase (r=−0.413). Splenic ADC correlated with splenic volume (r=−0.652), hepatic volume (r=−0.544) and chitotriosidase (r=−0.355). ConclusionHepatic and splenic ADC can detect hepatic and splenic infiltration in Gaucher disease and correlated with some parameters of disease severity.

Hepatic ADC map as an adjunct to conventional abdominal MRI to evaluate hepatic fibrotic and clinical cirrhotic severity in biliary atresia patients.

Hepatic apparent diffusion coefficient (ADC) values and ADC-related indices were correlated with the Mayo risk score for primary biliary cirrhosis (MRSPBC) and METAVIR scores of liver specimens to determine the clinical and pathological significance of diffusion-weighted magnetic resonance imaging (DWMRI). Thirty-two patients with biliary atresia (BA; mean age 461 days, range 11-4616 days) received magnetic resonance examinations from March 2009 to August 2013. A free-breathing DWMRI sequence was performed with the single-shot echo-planar imaging technique with b = 0 and 500 s/mm(2) in all 32 BA patients and 24 controls. We used the ordinal logistic regression test and Spearman rank correlation test to analyse the relationships between the MRSPBC and METAVIR fibrosis scores and right liver-to-psoas ADC ratios (LTPARs). BA patients had significantly lower LTPARs in both hepatic lobes than controls (p < 0.01). Right LTPARs, showing moderate intraobserver agreement (intraclass correlation coefficient = 0.736) and interobserver reliability (intraclass correlation coefficient = 0.659), were negatively correlated with MRSPBC and METAVIR fibrosis scores (R(2) = 0.398, p = 0.024 and R(2) = 0.628, p < 0.001, respectively). Right LTPARs may be used for long-term follow-up of cirrhosis severity in BA patients. • Hepatic ADC values by DWI correlates well with clinical/pathologic fibrosis scores • Periodic, non-invasive, quantitative imaging follow-up of patients with biliary cirrhosis is feasible • Information on cirrhosis severity could help decide on management options in children with BA • ADC values may be useful in this regard.

Normal hepatic parenchyma visibility and ADC quantification on diffusion-weighted MRI at 3 T: influence of age, gender, and iron content.

To investigate how normal liver parenchyma visibility on 3 T diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) quantification are influenced by age, gender, and iron content. Between February 2011 and April 2013, 86 patients (52 women) with normal livers who underwent respiratory-triggered abdominal 3 T DWI (b = 0, 150, 600, 1,000 s/mm(2)) were retrospectively included. Normal liver and spleen parenchyma visibility was scored independently by two readers. Correlations between visibility scores or ADC with age, gender, T2*, or recent serum ferritin (SF) were investigated. Liver visibility scores in b = 1,000 s/mm(2) images correlated with the age (Spearman R = -0.56 in women, -0.45 in men), T2* (R = 0.75) and SF (R = -0.64) and were significantly higher in women (P < 0.01). SF and T2* were within normal values (T2*: 13 - 31 ms, SF: 14 - 230 μg/L). Liver ADC correlated with visibility scores (R = 0.69) and T2* (R = 0.64) and was age- and gender-dependent. ADC ROI standard deviation negatively correlated with visibility scores (R = -0.65) and T2* (R = -0.62). The spleen visibility did not depend on age or gender. Normal liver parenchyma visibility in DWI is age- and gender-dependent, according to the iron content. Visibility scores and iron content significantly affect ADC quantification in the normal liver. Normal DWI liver visibility is gender-dependent and superior in women. In women, normal DWI liver visibility is superior before age 50 years. Normal DWI liver visibility negatively correlates with normal range iron content markers. Liver ADC quantification depends on liver iron content even within normal range. Normal liver T2* is age- and gender-dependent.

Diffusion Weighted MRI for Hepatic Fibrosis: Impact of b-Value

BackgroundHepatic fibrosis is a typical complication of chronic liver diseases resulting in cirrhosis that remains a major public health problem worldwide. Liver biopsy is currently the gold standard for diagnosing and staging hepatic fibrosis. Percutaneous liver biopsy; however, is an invasive procedure with risks of complications. Therefore, there is need for alternative non-invasive techniques to assess liver fibrosis and chronic liver diseases. In recent years, MRI techniques, including diffusion weighted imaging (DWI), have been developed for in vivo quantification of liver fibrosis.ObjectivesThe purpose of this study is to evaluate the utility of diffusion weighted MRI in the diagnosis and quantification of the degree of hepatic fibrosis and to investigate the influence of b-value.Patients and MethodsTwenty-four patients (13 males, 11 females), with a mean age of 46 years (36-73 years) diagnosed as chronic hepatitis and histopathologically proven liver fibrosis and 22 other patients (8 males, 14 females) with no clinical or biochemical findings of liver disease, with a mean age of 51.2 years (32-75 years) were included in the study. All patients with chronic hepatitis underwent percutaneous liver biopsy by an experienced hepatologist without sonographic guidance. The Knodell histology activity index (HAI) for grading of necroinflammatory changes and Metavir scoring system for staging of the liver fibrosis were used to record the severity of the disease. All patients were examined with a 1.5 Tesla MRI system and the patients underwent diffusion weighted imaging (DWI) with a routine hepatic MRI protocol. Different b-values including 250, 500, 750, and 1000 sec/mm 2 were used to calculate apparent diffusion coefficients.ResultsWe detected decreased apparent diffusion coefficient values in patients with hepatic fibrosis compared to patients without chronic hepatitis and there was a trend toward decrease in hepatic apparent diffusion coefficient values with an increasing degree of fibrosis.ConclusionsOur findings suggest that hepatic apparent diffusion coefficient measurement with a b-value of 750 sec/mm 2 or greater is useful in accurate quantification of liver fibrosis and necroinflammation.

Intra-voxel incoherent motion MRI in rodent model of diethylnitrosamine-induced liver fibrosis

Rationale and ObjectivesTo compare the apparent diffusion coefficient (ADC) and the perfusion fraction measured by intra-voxel incoherent motion (IVIM) Magnetic Resonance Imaging (MRI) with liver fibrosis degrees in a rodent model. Materials and MethodsAll experiments received approval from our institutional animal care and use committee. Liver fibrosis was induced in 13 rats by oral gavage with diethylnitrosamine; 4 untreated rats with normal livers were used as controls. Diffusion Weighted MRI was performed and 8 gradient factors (0, 50, 100, 150, 200, 300, 400 and 500s/mm2) were acquired. The values of ADC, true diffusion coefficient D and perfusion fraction f were measured based on Li Bihan’s method. The percentage of liver fibrosis was assessed via quantitative analysis of Masson trichrome staining using an average of 30 fields per section. The MRI measurements were compared to the histological fibrotic grade to evaluate the correlation between them. ResultsADC contained the contribution of diffusion and perfusion. The ADC and f values decreased significantly with the increasing fibrosis level (correlation coefficient: ADC: ρ=−0.781, p<0.001; f: ρ=−0.720, p=0.001); but D was poorly correlated with fibrosis level (ρ=−0.502, p=0.040). ConclusionThe hepatic ADC and the perfusion fraction f were significantly correlated with the liver fibrosis level; however, D was not. This might suggest that hepatic perfusion is altered during the progression of hepatic fibrosis.