Diffusion-Weighted MRI-Based Virtual Elastography and Shear-Wave Elastography for the Assessment of Breast Lesions.

BACKGROUND: Diffusion-weighted imaging (DWI)-based virtual MR elastography (DWI-vMRE) in the assessment of breast lesions is still in the research stage. PURPOSE: To investigate the usefulness of elasticity values on DWI-vMRE in the evaluation of breast lesions, and the correlation with the values calculated from shear-wave elastography (SWE). STUDY TYPE: Prospective. POPULATION/SUBJECTS: 153 patients (mean age ± standard deviation: 55 ± 12 years) with 153 pathological confirmed breast lesions (24 benign and 129 malignant lesions). FIELD STRENGTH/SEQUENCE: 1.5-T MRI, multi-b readout segmented echo planar imaging (b-values of 0, 200, 800, and 1000 sec/mm2). ASSESSMENT: For DWI-vMRE assessment, lesions were manually segmented using apparent diffusion coefficient (ADC0-1000) map, then the region of interests were copied to the map of shifted-ADC (sADC200-800, sADC 200-1500). For SWE assessment, the shear modulus of the lesions was measured by US elastic modulus (µUSE). Intraclass/interclass kappa coefficients were calculated to measure the consistency. STATISTICAL TESTS: Pearson's correlation was used to assess the relationship between sADC and µUSE. A receiver operating characteristic analysis with the area under the curve (AUC) was performed to compare the diagnostic accuracy between benign and malignant breast lesions of sADC and µUSE. A P value <0.05 was considered statistically significant. RESULTS: There were significant differences between benign and malignant breast lesions of µUSE (24.17 ± 10.64 vs. 37.20 ± 12.61), sADC200-800 (1.38 ± 0.31 vs. 0.97 ± 0.18 × 10-3 mm2/sec), and sADC200-1500 (1.14 ± 0.30 vs. 0.78 ± 0.13 × 10-3 mm2/sec). In all breast lesions, a moderate but significant correlation was observed between µUSE and sADC200-800/sADC200-1500 (r = -0.49/-0.44). AUC values to differentiate benign from malignant lesions were as follows: µUSE, 0.78; sADC200-800, 0.89; sADC200-1500, 0.89. DATA CONCLUSIONS: Both SWE and DWI-vMRE could be used for the differentiation of benign versus malignant breast lesions. Furthermore, DWI-vMRE with the use of sADC show relatively higher AUC values than SWE. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Value of T1 Mapping in the Non-invasive Assessment of Renal Pathologic Injury for Chronic Kidney Disease Patients.

PURPOSE: The objective of this study was to evaluate renal function and pathologic injury in chronic kidney disease (CKD) using T1 mapping. METHODS: We recruited fifteen healthy volunteers (HV) and seventy-five CKD patients to undergo T1 mapping examination, and renal parenchymal T1 values were measured. Spearman correlation analysis was used to evaluate the relevance between the pathologic injury score, estimated glomerular filtration rate (eGFR), and renal parenchymal T1 values. The diagnostic efficiency of T1 value in evaluating renal pathologic impairment was assessed. RESULTS: In all subjects, renal cortical T1 value was remarkably lower than renal medullary T1 value (P < 0.01). The renal medullary T1 value of HV was considerably lower than that of CKD patients in all stages (P < 0.05). The T1 values were negatively correlated with eGFR (cortex, r = -0.718; medulla, r = -0.645). The T1 values were positively correlated with glomerular injury score (cortex, r = 0.692; medulla, r = 0.632), tubulointerstitial injury score (cortex, r = 0.758; medulla, r = 0.690) (all P < 0.01). The area under the curve (AUC) of renal cortical and medullary T1 values were 0.914 and 0.880 to distinguish moderate-severe from mild renal injury groups. To differentiate mild renal injury group from control group, the AUC values of renal cortical and medullary T1 values were 0.879 and 0.856. CONCLUSION: T1 mapping has potential application value in non-invasively assessing renal pathologic injury in CKD.

Does Bi-Exponential Fitting Perform Better than Mono-Exponential Fitting in IVIM-DWI? An Assessment of Renal Pathological Injury of IgA Nephropathy.

BACKGROUND: Chronic kidney disease has become one of the world's major public health problems, immunoglobulin A (IgA) nephropathy is a common pathological type of CKD. Delaying the progression of IgA nephropathy has currently become the main clinical treatment strategy, precise evaluation of renal pathological injury during follow-up of patients with IgA nephropathy is important. Therefore, it is imperative to develop an accurate and non-invasive imaging technique for effective follow-up of renal pathological injury in patients with IgA nephropathy. OBJECTIVE: To investigate the clinical value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in assessing renal pathological injury in patients with immunoglobulin A (IgA) nephropathy compared with a mono-exponential model. METHODS: Altogether, 80 patients with IgA nephropathy were divided into the mild (41 cases) andmoderate-severe (m-s) renal injury groups (39 cases) according to pathology scores, and 20 healthy volunteers were recruited as controls. All participants underwent IVIM-DWI of the kidneys, and renal parenchymal apparent diffusion coefficient (ADC), pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) values were measured. One-way analysis of variance, receiver operating characteristic (ROC) curve analysis, and Pearson correlation analysis were performed for all the DWI-derived parameters. RESULTS: The DWI-derived parameters of the m-s renal injury group were significantly lower than those of the mild renal injury and control groups (P < 0.01). The ROC analysis revealed that f had the largest area under the ROC curve for differentiation between the m-s and mild renal injury groups and between the m-s renal injury and control groups. The f had the largest correlation coefficient with renal pathology scores (r=-0.81), followed by the D* (-0.69), ADC (-0.54), and D values (-0.53), respectively (all P<0.01). CONCLUSION: IVIM-DWI demonstrated better diagnostic performance than the mono-exponential model in assessing renal pathological injury in patients with IgA nephropathy.

Automated deep-learning system in the assessment of MRI-visible prostate cancer: comparison of advanced zoomed diffusion-weighted imaging and conventional technique.

BACKGROUND: Deep-learning-based computer-aided diagnosis (DL-CAD) systems using MRI for prostate cancer (PCa) detection have demonstrated good performance. Nevertheless, DL-CAD systems are vulnerable to high heterogeneities in DWI, which can interfere with DL-CAD assessments and impair performance. This study aims to compare PCa detection of DL-CAD between zoomed-field-of-view echo-planar DWI (z-DWI) and full-field-of-view DWI (f-DWI) and find the risk factors affecting DL-CAD diagnostic efficiency. METHODS: This retrospective study enrolled 354 consecutive participants who underwent MRI including T2WI, f-DWI, and z-DWI because of clinically suspected PCa. A DL-CAD was used to compare the performance of f-DWI and z-DWI both on a patient level and lesion level. We used the area under the curve (AUC) of receiver operating characteristics analysis and alternative free-response receiver operating characteristics analysis to compare the performances of DL-CAD using f- DWI and z-DWI. The risk factors affecting the DL-CAD were analyzed using logistic regression analyses. P values less than 0.05 were considered statistically significant. RESULTS: DL-CAD with z-DWI had a significantly better overall accuracy than that with f-DWI both on patient level and lesion level (AUCpatient: 0.89 vs. 0.86; AUClesion: 0.86 vs. 0.76; P < .001). The contrast-to-noise ratio (CNR) of lesions in DWI was an independent risk factor of false positives (odds ratio [OR] = 1.12; P < .001). Rectal susceptibility artifacts, lesion diameter, and apparent diffusion coefficients (ADC) were independent risk factors of both false positives (ORrectal susceptibility artifact = 5.46; ORdiameter, = 1.12; ORADC = 0.998; all P < .001) and false negatives (ORrectal susceptibility artifact = 3.31; ORdiameter = 0.82; ORADC = 1.007; all P ≤ .03) of DL-CAD. CONCLUSIONS: Z-DWI has potential to improve the detection performance of a prostate MRI based DL-CAD. TRIAL REGISTRATION: ChiCTR, NO. ChiCTR2100041834 . Registered 7 January 2021.

Single and combined toxicity assessment of primary or UV-aged microplastics and adsorbed organic pollutants on microalga Chlorella pyrenoidosa.

Microplastics (MPs), an emerging pollutant, have been increasingly raising concern due to the potential impacts on aquatic organisms. Moreover, the environmental aged MPs always exhibit different environmental behavior and interaction effect with organic pollutants from virgin MPs. In this work, the single and combined toxicity impact on Chlorella pyrenoidosa, a symbiont representative, has been investigated between MPs (e.g., polyamide microplastic (PA6), 75 µm) and organic pollutants (e.g., sulfamethoxazole (SMX) and dicamba (DCB)). Growth inhibition, chlorophyll accumulation, superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) were investigated with the primary or UV-aged PA6. Above 0.5 g/L PA6 (primary or UV-aged) inhibited cell growth and chlorophyll accumulation after 96 h cultivation as compared with the control. Besides, the inhibition impacts have enhanced as the UV-aging time extending in the single PA6 systems. The algae growth inhibition rate after 96 h cultivation in both the system i.e., single (PA6: 6.9%) and combined (PA6-SMX: 14.2%, PA6-DCB: 14.9%) was slightly lower than that of exposing in organic pollutants alone (SMX: 23.9%, DCB: 25.0%), while the chl. b concentration in 60 days UV-aged PA6 combined with SMX (1.19 mg/L) or DCB (1.40 mg/L) systems were higher than in single SMX (1.04 mg/L) or DCB (1.33 mg/L) system. In addition, there were several differences of the cellular oxidative stress in the combined system of SMX and DCB. Specially, it was not noticeable of three enzymatic activities for SMX exposing in the presence of primary or UV-aged PA6. While SOD, CAT, and MDA activities was obviously increasing after exposing in PA6 and DCB combined system, indicating the significant synergistic effect on algae cells damage. This research verified the remarkable combined toxicity between UV-aged MPs and organic pollutants on microalgae.

Comparison of Computed and Acquired DWI in the Assessment of Rectal Cancer: Image Quality and Preoperative Staging.

Objective: The aim of the study was to evaluate the computed diffusion-weighted images (DWI) in image quality and diagnostic performance of rectal cancer by comparing with the acquired DWI. Methods: A total of 103 consecutive patients with primary rectal cancer were enrolled in this study. All patients underwent two DWI sequences, namely, conventional acquisition with b = 0 and 1,000 s/mm2 (aDWIb1,000) and another with b = 0 and 700 s/mm2 on a 3.0T MR scanner (MAGNETOM Prisma; Siemens Healthcare, Germany). The images (b = 0 and 700 s/mm2) were used to compute the diffusion images with b value of 1,000 s/mm2 (cDWIb1,000). Qualitative and quantitative analysis of both computed and acquired DWI images was performed, namely, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and signal intensity ratio (SIR), and also diagnostic staging performance. Interclass correlation coefficients, weighted κ coefficient, Friedman test, Wilcoxon paired test, and McNemar or Fisher test were used for repeatability and comparison assessment. Results: Compared with the aDWIb1,000 images, the cDWIb1,000 ones exhibited significant higher scores of subjective image quality (all P <0.050). SNR, SIR, and CNR of the cDWIb1,000 images were superior to those of the aDWIb1,000 ones (P <0.001). The overall diagnostic accuracy of computed images was higher than that of the aDWIb1,000 images in T stage (P <0.001), with markedly better sensitivity and specificity in distinguishing T1-2 tumors from the T3-4 ones (P <0.050). Conclusion: cDWIb1,000 images from lower b values might be a useful alternative option and comparable to the acquired DWI, providing better image quality and diagnostic performance in preoperative rectal cancer staging.

Diffusion kurtosis imaging for the assessment of renal fibrosis of chronic kidney disease: A preliminary study.

PURPOSE: To investigate the potential of diffusion kurtosis imaging (DKI) for the assessment of renal fibrosis in chronic kidney disease (CKD), using histopathology as the reference standard. METHODS: Eighty-nine CKD patients and twenty healthy volunteers were recruited in this study. DKI was performed in all participants and all CKD patients received renal biopsy. The values of mean diffusivity (MD) and mean kurtosis (MK) in the renal cortex and medulla were compared between CKD patients and healthy volunteers. The Spearman correlation coefficient was calculated to assess the relationship between MD, MK values and the estimated glomerular filtration rate (eGFR), serum creatinine (SCr), 24 h urinary protein (24 h-UPRO), histopathological fibrosis score. RESULTS: The medullary MD values were significantly lower than cortex, while the cortical MK values were significantly lower than medulla for all participants. Renal parenchymal MD values were significantly lower in the CKD patients than healthy controls, whereas MK values were significantly higher in the CKD patients than healthy controls. In the CKD patients, the significantly negative correlation was observed between the renal parenchymal MD values and the 24 h-UPRO, SCr, histopathological fibrosis score, as well as between the renal parenchymal MK values and the eGFR, while the significantly positive correlation was found between the renal parenchymal MD values and the eGFR, as well as between the renal parenchymal MK values and the 24 h-UPRO, SCr, histopathological fibrosis score. CONCLUSION: DKI shows great potential in the noninvasive assessment of renal fibrosis in CKD.

Pathological assessment of chronic kidney disease with DWI: Is there an added value for diffusion kurtosis imaging?

BACKGROUND: Chronic kidney disease (CKD) is a worldwide health problem, precise functional and pathological assessment is beneficial to better treatment. Diffusion kurtosis imaging (DKI) can evaluate non-Gaussian diffusion and may help to assess renal pathology and function. PURPOSE: To assess pathological and functional alterations in CKD using DKI compared with diffusion-weighted imaging (DWI). STUDY TYPE: Prospective study. POPULATION: 70 CKD patients and 20 healthy volunteers. FIELD STRENGTH: 1.5 T. ASSESSMENT: All participants underwent DKI, and apparent diffusion coefficient (ADC), mean diffusivity (MD), and mean kurtosis (MK) of renal parenchyma were acquired. Correlation between renal parenchymal ADC, MD, MK, and estimated glomerular filtration rate (eGFR), pathological scores were assessed. The diagnostic efficacy of ADC, MD, and MK for assessing the degree of renal pathological injury were compared. STATISTICAL TESTS: ANOVA, Spearman correlation analysis, and ROC curve analysis. RESULTS: The cortical ADC, MD were significantly higher than medulla for all participants, whereas medullary MK was significantly higher than cortex (P < 0.01). Whether eGFR reduced or not, renal parenchymal MK were significantly higher in patients than controls (P < 0.05). Positive correlation was found between eGFR and ADC (cortex, r = 0.562; medulla, r = 0.527), and negative correlation between eGFR and MK (cortex, r = -0.786; medulla, r = -0.709) (all P < 0.001). There was positive correlation between MK and glomerular injury (cortex, r = 0.681; medulla, r = 0.652), tubulointerstitial lesion (cortex, r = 0.650; medulla, r = 0.599) (all P < 0.001). For discrimination between mild and m-s renal injury group, the AUC values of ADC, MD, MK were cortex: 0.723, 0.655, 0.864 and medulla: 0.718, 0.581, 0.829. The AUC values of ADC, MD, MK were cortex: 0.708, 0.679, 0.770 and medulla: 0.713, 0.830, 0.780 for differentiating control group from mild renal injury group. DATA CONCLUSION: DKI is practicable for noninvasive assessment of renal pathology and function of CKD, DKI offer better diagnostic performance than DWI. Evidence Level 1 Technical Efficacy 2.

Role of free-breathing motion-corrected late gadolinium enhancement technique for image quality assessment and LGE quantification.

OBJECTIVE: To compare the image quality and late gadolinium enhancement (LGE) quantification between free-breathing motion-corrected and conventional breath-hold LGE method in a variety of cardiovascular diseases. MATERIALS AND METHODS: 149 consecutive patients underwent contrast-enhanced cardiac magnetic resonance examination employing both free-breathing motion-corrected LGE and conventional breath-hold LGE method. Scan time, contrast-to-noise ratio, overall image quality score and LGE mass were measured and analyzed statistically. RESULTS: Free-breathing motion-corrected LGE method had a shorter scan time and higher overall image quality score in comparison with conventional breath-hold LGE method (p < 0.001). Univariate/multivariate logistic regression analysis showed that breath-holding difficulty, high heart rate and arrhythmia could be predictive factors possibly for an inferior image quality score (p < 0.05 for all). The contrast-to-noise ratios of free-breathing motion-corrected LGE images were higher than those of conventional breath-hold LGE images (p < 0.001). In the cases with subepicardial and/or transmural myocardial enhancement, the measured LGE masses were larger on free-breathing motion-corrected LGE images in comparison with those on conventional breath-hold LGE images (p < 0.05). CONCLUSION: Free-breathing motion-corrected LGE could be a better choice for patients who need contrast-enhanced cardiac MRI and have one or more of the risk factors for an inferior image quality score, including breath-holding difficulty, high heart rate and arrhythmia. However, an overestimation of LGE mass on free-breathing motion-corrected LGE image should be taken into consideration when LGE pattern involves subepicardial and/or transmural myocardium.

A Noninvasive Assessment of Tumor Proliferation in Lung cancer Patients using Intravoxel Incoherent Motion Magnetic Resonance Imaging.

Ki-67 is a nuclear antigen widely used in routine pathologic analyses as a tumor cell proliferation marker for lung cancer. However, Ki-67 expression analyses using immunohistochemistry (IHC) are invasive and frequently influenced by tissue sampling quality. In this study, we assessed the feasibility of noninvasive magnetic resonance imaging (MRI) in predicting the Ki-67 labeling indices (LIs). A total of 51 lung cancer patients, including 42 non-small cell lung cancer (NSCLC) cases and nine small cell lung cancer (SCLC) cases, were enrolled in this study. Quantitative MRI parameters from conventional diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI) were obtained, and their correlations with tumor tissue Ki-67 expression were analyzed. We found that the true diffusion coefficient (D value) from IVIM was negatively correlated with Ki-67 expression (Spearman r = -0.76, P < 0.001). The D values in the high Ki-67 group were significantly lower than those in the low Ki-67 group (0.90 ± 0.21 × 10-3 mm2/s vs. 1.22 ± 0.30 × 10-3 mm2/s). Among three MRI techniques used, D values from IVIM showed the best performance for distinguishing the high Ki-67 group from low Ki-67 group in receiver operating characteristic (ROC) analysis with an area under the ROC curve (AUROC) of 0.85 (95% CI: 0.73-0.97, P < 0.05). Moreover, D values performed well for differentiating SCLC from NSCLC with an AUROC of 0.82 (95% CI: 0.68-0.90), Youden index of 0.72, and F1 score of 0.81. In conclusion, D values were negatively correlated with Ki-67 expression in lung cancer tissues and can be used to distinguish high from low proliferation statuses, as well as SCLC from NSCLC.

Human health risk assessment of antibiotic resistance associated with antibiotic residues in the environment: A review.

The extensive use of antibiotics leading to the rapid spread of antibiotic resistance poses high health risks to humans, but to date there is still lack of a quantitative model to properly assess the risks. Concerns over the health risk of antibiotic residues in the environment are mainly (1) the potential hazard of ingested antibiotic residues in the environment altering the human microbiome and promoting emergence and selection for bacteria resistance inhabiting the human body, and (2) the potential hazard of creating a selection pressure on environmental microbiome and leading to reservoirs of antibiotic resistance in the environment. We provide a holistic view of health risk assessment of antibiotic resistance associated with antibiotic residues in the environment in contrast with that of the antibiotic resistant bacteria and discuss the main knowledge gaps and the future research that should be prioritized to achieve the quantitative risk assessment. We examined and summarized the available data and information on the four core elements of antibiotic resistance associated with antibiotic residues in the environment: hazard identification, exposure assessment, dose-response assessment, and risk characterization. The data required to characterize the risks of antibiotic residues in the environment is severely limited. The main future research needs have been identified to enable better assessments of antibiotic resistance associated with antibiotic residues in the environment: (1) establishment of a standardized monitoring guide of antibiotic residues and antibiotic resistance in the environment, (2) derivation of the relationship between antibiotic levels and pathogenic antibiotic-resistance development in different settings, and (3) establishment of the dose-response relationship between pathogenic antibiotic resistant bacteria and various infection diseases. After identification of key risk determinant parameters, we propose a conceptual framework of human health risk assessments of antibiotic residues in the environment. CAPSULE: A holistic view of human health risk assessment of antibiotic residues in the environment was provided.

A comparative study of MR extracellular volume fraction measurement and two-dimensional shear-wave elastography in assessment of liver fibrosis with chronic hepatitis B.

OBJECTIVE: To evaluate the value of MR liver extracellular volume (ECVliver) in assessment of liver fibrosis with chronic hepatitis B (CHB), and to compare its performance with two-dimensional (2D) shear-wave elastography (SWE). MATERIALS AND METHODS: A total of 68 CHB patients who were histologically diagnosed as fibrosis stages F0 to F4 were retrospectively analyzed. All patients underwent gadopentetate dimeglumine-enhanced T1-mapping and 2D SWE. ECVliver and liver stiffness were measured and compared between fibrosis subgroups; their correlations with histologic findings were evaluated using Spearman correlation test and multiple regression analysis. Diagnostic performance in evaluating liver fibrosis stages was assessed and compared using receiver-operating characteristic analysis. RESULTS: Both ECVliver and liver stiffness increased as the fibrosis score increased (F = 17.08 to 10.99, P < 0.001). ECVliver displayed a strong correlation with fibrosis stage (r = 0.740, P < 0.001), and liver stiffness displayed a moderate correlation (r = 0.651, P < 0.001); multivariate analysis revealed that only ECVliver was independently correlated with fibrosis stage (P < 0.001). Univariate analyses showed significant correlations of ECVliver with fibrosis stage, inflammatory activity, and platelet count; among all, the fibrosis stage had the highest correlation coefficient and was the only independent factor (P < 0.001). Overall, ECVliver had no significant different performance compared with 2D SWE for the identification of both fibrosis stage s ≥ F2 and F4 (P = 0.868 and 0.171). CONCLUSION: MR ECVliver plays a promising role in the prediction of liver fibrosis for patients with CHB, comparable to 2D SWE.

Assessment of Microvascular Invasion of Hepatocellular Carcinoma with Diffusion Kurtosis Imaging.

Purpose To evaluate the potential role of diffusion kurtosis imaging and conventional magnetic resonance (MR) imaging findings including standard monoexponential model of diffusion-weighted imaging and morphologic features for preoperative prediction of microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Materials and Methods Institutional review board approval and written informed consent were obtained. Between September 2015 and November 2016, 84 patients (median age, 54 years; range, 29-79 years) with 92 histopathologically confirmed HCCs (40 MVI-positive lesions and 52 MVI-negative lesions) were analyzed. Preoperative MR imaging examinations including diffusion kurtosis imaging (b values: 0, 200, 500, 1000, 1500, and 2000 sec/mm2) were performed and kurtosis, diffusivity, and apparent diffusion coefficient maps were calculated. Morphologic features of conventional MR images were also evaluated. Univariate and multivariate logistic regression analyses were used to evaluate the relative value of these parameters as potential predictors of MVI. Results Features significantly related to MVI of HCC at univariate analysis were increased mean kurtosis value (P < .001), decreased mean diffusivity value (P = .033) and apparent diffusion coefficient value (P = .011), and presence of infiltrative border with irregular shape (P = .005) and irregular circumferential enhancement (P = .026). At multivariate analysis, mean kurtosis value (odds ratio, 6.25; P = .001), as well as irregular circumferential enhancement (odds ratio, 6.92; P = .046), were independent risk factors for MVI of HCC. The mean kurtosis value for MVI of HCC showed an area under the receiver operating characteristic curve of 0.784 (optimal cutoff value was 0.917). Conclusion Higher mean kurtosis values in combination with irregular circumferential enhancement are potential predictive biomarkers for MVI of HCC. © RSNA, 2017.

Intravoxel incoherent motion diffusion-weighted imaging for the assessment of renal fibrosis of chronic kidney disease: A preliminary study.

PURPOSE: To investigate the potential of Intravoxel incoherent motion diffusion-weighted imaging(IVIM-DWI) for the assessment of renal fibrosis in chronic kidney disease (CKD), using histopathology as a reference standard. METHODS: Eighty-five CKD patients and twenty healthy volunteers were recruited in this study. IVIM-DWI was performed in all of the participants, and all of the CKD patients underwent renal biopsy. The mean values of the true diffusion coefficient (D), pseudo diffusion coefficient (D*) and perfusion fraction (f) in the renal cortex and medulla were compared between the CKD patients and healthy volunteers. The Spearman correlation coefficient was calculated to assess the relationship between the D, D*,f values and the estimated glomerular filtration rate (eGFR), serum creatinine level (SCr), 24h urinary protein level (24h-UPRO), histopathological fibrosis scores. RESULTS: The D, D* and f values were significantly lower in medulla than in the cortex for all of the participants. All of the IVIM parameters were significantly lower in the CKD patients than in the healthy controls. In the CKD patients, a significant negative correlation was found between the renal parenchymal D, D*,f values and the 24h-UPRO, as well as between the renal parenchymal D, f values and the SCr. There was a significant positive correlation between all of the IVIM parameters and the eGFR. All of the IVIM parameters exhibited a significant negative correlation with the histopathological fibrosis score. CONCLUSION: IVIM-DWI shows great potential in the noninvasive assessment of renal fibrosis in CKD.

Assessment of liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy: a comparative study with portal vein ligation.

BACKGROUND: To investigate the diagnostic value of diffusion kurtosis imaging (DKI) and diffusion-weighted imaging (DWI) in assessing liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) compared with portal vein ligation (PVL). METHODS: Thirty rats were divided into the ALPPS, PVL, and control groups. DKI and DWI were performed before and 7 days after surgery. Corrected apparent diffusion (D), kurtosis (K) and apparent diffusion coefficient (ADC) were calculated and compared, radiologic-pathologic correlations were evaluated. RESULTS: The volume of the right median lobe increased significantly after ALPPS. There were larger cellular diameters after ALPPS and PVL (P = 0.0003). The proliferative indexes of Ki-67 and hepatocyte growth factor were higher after ALPPS (P = 0.0024/0.0433). D, K and ADC values differed between the groups (P = 0.021/0.0015/0.0008). A significant correlation existed between D and the hepatocyte size (r = -0.523), no correlations existed in ADC and K (P = 0.159/0.111). The proliferative indexes showed moderate negative correlations with ADC (r = -0.484/-0.537) and no correlations with D and K (P = 0.100-0.877). DISCUSSION: Liver regeneration after ALPPS was effective and superior to PVL. DKI, especially the D map, may provide added value in evaluating the microstructure of liver regeneration after ALPPS, but this model alone may perform no better than the standard monoexponential model of DWI.

Dynamic contrast-enhanced (DCE) MRI assessment of microvascular characteristics in the murine orthotopic pancreatic cancer model.

OBJECT: The aim of this study was to assess the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI)-derived pharmacokinetic parameters between two contrast agents in a murine orthotopic pancreatic cancer model and to evaluate the tumor heterogeneity and the potential association between kinetic parameters and angiogenic markers such as the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression by immunohistochemistry. MATERIALS AND METHODS: Human pancreatic adenocarcinoma cell line MIAPaCa-2 was injected into the pancreas of BALB/C nu/nu mice. DCE-MRI was performed using Gd-DTPA and Gd-EOB-DTPA. Quantitative and semi-quantitative vascular parameters (K(trans), Kep, Ve and AUC) were calculated by using a dedicated postprocessing software program. Values were compared with tumor rim, tumor core and the entire tumor. The MVD and VEGF expressions between tumor rim and tumor core were also compared. RESULTS: There were no significant differences in K(trans), Kep, Ve, and AUC values of the three groups when using Gd-DTPA. However there were significant differences in K(trans), Kep, and AUC values of the three groups when using Gd-EOB-DTPA (P=0.014, 0.022, 0.007, respectively), in addition, the K(trans) and Kep values of tumor core were significantly lower than those of the entire tumor (adjusted P=0.014 and 0.027, respectively), the AUC values of core were significantly lower than those of the entire tumor and rim (adjusted P=0.039 and 0.009, respectively). Immunohistology results revealed that MVD and VEGF expression in the tumor rim was significantly higher than that in the core. There was positive correlation between AUC and MVD, VEGF. CONCLUSION: The murine orthotopic pancreatic cancer model provides an ideal animal model to study human pancreatic cancer. It can more sensitively semi-quantitatively and quantitatively analyze tumor angiogenesis through selecting the albumin-binding contrast agent.