Search

Purpose: Ectopic fat accumulation and abdominal fat distribution may have different cardiometabolic risk profiles. This study aimed to assess the associations between various magnetic resonance imaging (MRI)-acquired fat depots and cardiometabolic risk factors. Methods: A total of 320 subjects with median age of 59 years, 148 men and 172 women, were enrolled in the study. Visceral adipose tissue (VAT) area and fat fraction (FF), subcutaneous adipose tissue (SAT) area and FF at the L1–L2 levels, preperitoneal adipose tissue (pPAT) area and FF, hepatic FF, pancreatic FF, and intramuscular FF were assessed by MRI FF maps. The associations of various MRI-acquired fat depots with blood pressure, glucose, and lipid were examined using sex-stratified linear regression. Logistic regression stratified by sex was used to analyze the association of various MRI-acquired fat depots with the risk of hypertension, T2DM, and dyslipidemia. Results: The intraclass correlation coefficient (ICC) values were >0.9, which suggested good interobserver and intraobserver agreement. VAT area, V/S, hepatic fat, pancreatic fat, and pPAT rather than SAT area were significantly associated with multiple cardiometabolic risk factors (all p < 0.05). However, the patterns of these correlations varied by sex and specific risk factors. Also, VAT and SAT FF were only significantly associated with multiple cardiometabolic risk factors in women (all p < 0.05). Conclusions: VAT, hepatic fat, pancreatic fat, and pPAT were associated with cardiovascular metabolic risk factors independent of BMI. The patterns of these correlations were related to gender. These findings further the understanding of the association between ectopic fat deposition and cardiometabolic risk factors and help to better understand the obesity heterogeneity. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the value of diffusion tensor imaging (DTI) and tractography in renal allografts at the early stage after kidney transplantation.Methods: This study was approved by the institutional ethical review committee, and written informed consent was obtained. A total of 54 renal allograft recipients 2-3 weeks after transplantation and 26 age-matched healthy volunteers underwent renal DTI with a 3.0-T magnetic resonance imaging (MRI) system. Recipients were divided into three groups according to the estimated glomerular filtration rate (eGFR). Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the cortex and medulla were measured and compared among the groups. Whole-kidney tractography was performed. Correlation of eGFR with diffusion parameters was evaluated.Results: In allografts with stable function, the medullary ADC was higher and the cortical FA was lower (p < 0.001) than in healthy kidneys. The cortical ADC, medullary ADC and FA decreased as the allograft function declined, and with a positive correlation with eGFR (p < 0.001); cortical FA did not. Tractography demonstrated a decrease of tract density in impaired functional allografts.Conclusions: Renal DTI produces reliable results to assess renal allograft function at the early stage after transplantation.Key Points: • DTI and tractography can evaluate renal allograft function at an early stage • Medullary FA, cortical and medullary ADC can effectively evaluate allograft function • Medullary FA, cortical and medullary ADC are correlated with eGFR in renal allografts • Medullary ADC increased and cortical FA decreased in stable allografts compared to control subjects • Medullary FA, cortical and medullary ADC decreased and allograft function declined. [ABSTRACT FROM AUTHOR]

Background. This study aimed to investigate whether diffusion-weighted imaging (DWI) could contribute to the discrimination between benign and malignant renal cancer. Methods. We searched the PubMed electronic database for eligible studies. STATA 12.0 software was used for statistical analysis. The SMD and 95% CI were calculated. Results. Decreased ADC signal was seen in all renal cancer patients (cancer tissue versus normal tissue: SMD = 1.63 and 95% CI = 0.96~2.29, P<0.001; cancer tissue versus benign tissue: SMD = 2.22 and 95% CI = 1.53~2.90 and P<0.001, resp.). MRI machine type-stratified analysis showed that decreased ADC signal was found by all included MRI machine types in cancer tissues compared with benign cancer tissues (all P<0.05). The ADC values of renal cancer patients were significantly lower than those of normal controls for all included P values (all P<0.05), and there was a decreased ADC signal at b-500, b-600, b-1000, b-500, and 1000 gradients compared with benign cancer tissues (all P<0.05). Conclusion. Our study concluded that decreased ADC signal presented in DWI may be essential for the differential diagnosis of renal cancer. [ABSTRACT FROM AUTHOR]

Background: To determine the clinical value of apparent diffusion coefficient (ADC) measurement by diffusion weighted magnetic resonance imaging (DW-MRI) in differentiating renal tumors.Methods: Electronic databases were searched using combinations of keywords and free words relating to renal tumor, ADC and DW-MRI. Based on carefully selected inclusion and exclusion criteria, relevant case-control studies were identified and the related clinical data was acquired. Statistical analyses were performed using STATA 12.0 (Stata Corporation, College station, TX).Results: Sixteen case-control studies were ultimately included in the present meta-analysis. These 16 high quality studies contained a combined total of 438 normal renal tissues and 832 renal tumor lesions (597 malignant and 235 benign). The results revealed that ADC values of malignant renal tumor tissues were markedly lower than normal renal tissues and benign renal tumor tissues. ADC values of benign renal tumor tissues were also significantly lower than normal renal tissue.Conclusions: ADC measurement by DW-MRI provided clinically useful information on the internal structure of renal tumors and could be an important radiographic index for differentiation of malignant renal tumors from benign renal tumors. [ABSTRACT FROM AUTHOR]

Purpose To evaluate renal allografts function early after transplantation using intravoxel incoherent motion (IVIM) and arterial spin labeling (ASL) MRI. Methods This prospective study was approved by the local ethics committee, and written informed consent was obtained from all participants. A total of 82 participants with 62 renal allograft recipients (2–4 weeks after kidney transplantation) and 20 volunteers were enrolled to be scanned using IVIM and ASL MRI on a 3.0 T MR scanner. Recipients were divided into two groups with either normal or impaired function according to the estimated glomerular filtration rate (eGFR) with a threshold of 60 ml/min/1.73 m 2 . The apparent diffusion coefficient (ADC) of pure diffusion (ADC slow ), the ADC of pseudodiffusion (ADC fast ), perfusion fraction (PF), and renal blood flow (RBF) of cortex were compared among three groups. The correlation of ADC slow , ADC fast , PF and RBF with eGFR was evaluated. The receiver operating characteristic (ROC) curve and binary logistic regression analyses were performed to assess the diagnostic efficiency of using IVIM and ASL parameters to discriminate allografts with impaired function from normal function. P < 0.05 was considered statistically significant. Results In allografts with normal function, no significant difference of mean cortical ADC slow , ADC fast , and PF was found compared with healthy controls ( P > 0.05). Cortical RBF in allografts with normal function was statistically lower than that of healthy controls ( P < 0.001). Mean cortical ADC slow , ADC fast , PF and RBF were lower for allografts with impaired function than that with normal function ( P < 0.05). Mean cortical ADC slow , ADC fast , PF and RBF showed a positive correlation with eGFR (all P < 0.01) for recipients. The combination of IVIM and ASL MRI showed a higher area under the ROC curve (AUC) (0.865) than that of ASL MRI alone ( P = 0.02). Conclusion Combined IVIM and ASL MRI can better evaluate the diffusion and perfusion properties for allografts early after kidney transplantation. [ABSTRACT FROM AUTHOR]