Alterations of Cerebral Blood Flow and its Connectivity Patterns Measured with Arterial Spin Labeling in Mild Cognitive Impairment.

OBJECTIVES: Cerebral blood flow (CBF) is an important index for measuring brain function. Studies have shown that regional CBF changes inconsistently in mild cognitive impairment (MCI). Arterial spin labeling (ASL) is widely used in the study of CBF in patients with MCI. However, alterations in CBF connectivity in these patients remain poorly understood. METHODS: In this study, 3D pseudo-continuous arterial spin labeling (3D-pCASL) technology was used to investigate the changes in regional CBF and CBF connectivity between 32 MCI patients and 32 healthy controls. The normalized CBF was used to reduce inter-subject variations. Both group comparisons in the CBF and correlations between CBF alterations and cognitive scores were assessed. CBF connectivity of brain regions with regional CBF differences was also compared between groups. RESULTS: We found that compared with that in controls, the CBF was significantly reduced in the left superior parietal gyrus in MCI patients, whereas it was increased in the left precentral gyrus, right superior temporal gyrus, right putamen, and left supplementary motor area. In patients with MCI, significant correlations were identified between CBF and neuropsychological scales. Importantly, MCI patients exhibited CBF disconnections between the left supplementary motor area and the left superior parietal gyrus. CONCLUSION: This study found that there are not only changes in regional CBF but also in CBF connectivity patterns in MCI patients compared with controls. These observations may provide a novel explanation for the neural mechanism underlying the pathophysiology in patients with Alzheimer's disease and MCI.

Up-regulation of LINC00665 contributes to the progression of glioma and correlates with its MRI characteristics.

BACKGROUND: LncRNA LINC00665 partakes in controlling the malignant phenotype of cancer cells, but its role in glioma and the related regulatory mechanism remain uncertain. METHODS: RT-PCR was exploited to examine LINC00665 expression. The relationships among the LINC00665 expression, the clinicopathologic values and magnetic resonance imaging (MRI) characteristics of glioma were analyzed. The multiplication, movement, and aggressiveness of glioma cell lines were evaluated by CCK-8, EdU, and Transwell experiments after constructing LINC00665 overexpression and LINC00665 knockdown cell models. A dual-luciferase reporter gene experiment and RIP experiment were executed to validate the interactions between LINC00665 and miR-129-5p, and between miR-129-5p and HMGB1. Western blot and RT-PCR were conducted to find the impact of LINC00665 and miR-129-5p on HMGB1 expression. Nude mouse model was also constructed to examine the impact of LINC00665 on multiplication and aggressiveness of glioma cells in vivo. RESULTS: LINC00665 expression was markedly increased in glioma. High LINC00665 expression in glioma was closely linked to larger tumor diameter, higher pathologic grade, heterogeneous MRI signal of the tumor, increased peritumoral edema, and stronger MRI enhancement characteristics. LINC00665 overexpression facilitated the malignant behavior of glioma cells, while LINC00665 knockdown played the reverse role. Mechanistically, LINC00665 could decoy miR-129-5p, and indirectly increased HMGB1 expression. CONCLUSION: LINC00665 functions as an oncogenic lncRNA in glioma, to accelerate glioma progression by modulating miR-129-5p and increasing HMGB1 expression.

MR diffusion kurtosis imaging for cancer diagnosis: A meta-analysis of the diagnostic accuracy of quantitative kurtosis value and diffusion coefficient.

PURPOSE: To perform a meta-analysis for assessing the accuracy of diffusion kurtosis imaging (DKI)-derived quantitative parameters (kurtosis values, K; and corrected diffusion coefficients non-Gaussian bias, D) in separating malignant cancers from benign lesions. METHODS: Relevant studies were searched in PubMed and Cochrane Library databases and were analyzed by Meta-DiSc software. RESULTS: Fourteen eligible studies involving 1847 lesions in 1107 patients (895 were benign and 952 were malignant) were included. Pooled analysis showed the sensitivity, specificity, positive likelihood ratio (LR), and negative LR were respectively 0.83 (95% CI, 0.79-0.85), 0.83 (95% CI, 0.80-0.86), 4.61 (95% CI, 2.98-7.14), and 0.22 (95% CI, 0.18-0.28) for K, with the overall area under curve (AUC) of 0.89. The sensitivity, specificity, positive LR, and negative LR were 0.85 (95% CI, 0.80-0.88), 0.85 (95% CI, 0.79-0.89), 6.39 (95% CI, 3.14-12.99), and 0.18 (95% CI, 0.14-0.23) for D, with the overall AUC of 0.92. The sensitivity, specificity, positive LR, and negative LR for apparent diffusion coefficient (ADC) derived from standard diffusion-weighted imaging (DWI) were 0.82 (95% CI, 0.79-0.84), 0.85 (95% CI, 0.82-0.88), 4.75 (95% CI, 3.38-6.68), and 0.24 (95% CI, 0.19-0.29), with the overall AUC of 0.89. The superiority of D to K and ADC was also confirmed by the subgroup analysis of prostate cancer. CONCLUSION: Our findings suggest that DKI should be added to the routine imaging protocol for screening cancer, with the highest diagnostic accuracy of diffusion coefficients.

ADC at 3.0 T as a noninvasive biomarker for preoperative prediction of Ki67 expression in invasive ductal carcinoma of breast.

PURPOSE: To investigate the role of apparent diffusion coefficient (ADC) as an imaging biomarker for invasive ductal carcinoma (IDC) in the breast. METHODS: Seventy-one patients undergoing 3.0 Tesla DWI were retrospectively enrolled. Correlations between the ADC values and prognostic factors were evaluated. RESULTS: Multivariate regression analyses showed that Ki67 expression and molecular subtype were independently associated with the ADC. Discriminant analysis excluded the ADC as a good biomarker for subtype, but the mean ADC significantly distinguished Ki67-positive (low ADC) from Ki67-negative (high ADC) lesions, as observed in the in ROC curves, with a diagnostic sensitivity of 1.00 and a cut-off value of 0.97 × 10-3 mm2/s. CONCLUSION: The ADC may be helpful for predicting Ki67 expression in IDC preoperatively.

Patients with type 2 diabetes exhibit cognitive impairment with changes of metabolite concentration in the left hippocampus.

Type 2 diabetes mellitus (T2DM) is associated with cognitive dysfunction. Previous studies have reported the relationship between cerebral metabolite changes and glucose levels. However, the specific aspects of cognition that are affected by metabolic changes in T2DM- related cognitive impairment remain undetermined. In this study, 188 T2DM patients and 266 controls were recruited. Proton magnetic resonance spectra with a single voxel stimulated echo acquisition mode (STEAM) were acquired from the left hippocampus and the frontal lobe. Presence of T2DM negatively affected the scores of Mini-Mental State Examination (MMSE), sub-tests (i.e., attention and language) of MMSE, Montreal Cognitive Assessment (MoCA) according to the Beijing version, and sub-tests (i.e., visuospatial/executive reasoning, attention, and language) of MoCA, rather than the Wechsler Memory Scale - Revised in China (WMS-RC), and all memory sub-tests contained with the MMSE and MoCA frameworks. T2DM positively affected creatine and myoinositol peak areas from the left hippocampus, rather than metabolites in the left frontal lobe. Negative correlations were shown between the left hippocampal myoinositol levels and language scores, and between the left hippocampal creatine levels and visuospatial/executive scores in T2DM. These findings suggest that T2DM may be an independent risk factor for cognitive impairment. Further, the cognitive domains of visuospatial /executive reasoning, attention and language may be predominantly impaired in the early phases of T2DM-related cognitive impairment. In addition, left hippocampal myoinositol and creatine concentrations were associated with cognitive impairment in patients with T2DM.

Contrast-enhanced dynamic and diffusion-weighted MR imaging at 3.0T to assess aggressiveness of bladder cancer.

BACKGROUND: Diffusion weighted magnetic resonance imaging (DWI) and dynamic contrast-enhanced (DCE) MRI have been considered useful for pathological staging and histological grading in bladder cancer. To our knowledge, no study has combined the two imaging modalities together to assess aggressiveness of bladder cancer. OBJECTIVE: To assess the clinical aggressiveness of bladder cancer with DCE MRI and DWI at 3.0T. MATERIALS AND METHODS: A total of 59 patients with 69 pathologically confirmed tumor lesions were included in this study. All patients underwent MR examination at 3.0T basing on DWI and DCE imaging. Tumor staging and histological grade were evaluated. The aggressiveness of bladder cancer was classified as low-, intermediate-, or high-aggressiveness according to its pathological phenotype. Apparent diffusion coefficient (ADC) value and semi-quantitative parameters (wash-in rate and wash-out rate) were determined. The correlation between clinical aggressiveness and ADC value, wash-in rate and wash-out rate were analyzed. In addition, the diagnostic accuracy of the diffusion and semi-quantitative parameters were estimated using receiver operating characteristic curve (ROC). RESULTS: Aggressiveness of bladder cancer is negatively correlated with ADC value (r=-0.705, p<0.0001) and wash-out rate (r=-0.719, p<0.0001). The tumor ADC value is positively correlated with wash-out rate (r=0.555, p<0.0001). The diagnostic specificity and accuracy using tumor ADC value and wash-out for the tumor with size <24mm were better than that tumors with size ≥24mm. The sensitivity, specificity and accuracy of ADC and wash-out rate in combination in diagnosis of bladder cancer aggressiveness were 96.7%, 94.9% and 95.7%, respectively. ROC curve revealed the diagnostic performance of aggressiveness of bladder cancer using ADC value and wash-out rate were 0.928 (cut-off value: 0.905×10(-3)mm(2)/s) and 0.891 (cut-off value: 0.685min(-1)), respectively. CONCLUSION: ADC and wash-out rate derived from DWI and DCE-MRI at 3.0T have good potential to assess the aggressiveness of bladder cancer and the accuracy was greater for ADC than for semi-quantitative parameters.

Diffusion tensor imaging in spinal cord compression.

BACKGROUND: Although diffusion tensor imaging has been successfully applied in brain research for decades, several main difficulties have hindered its extended utilization in spinal cord imaging. PURPOSE: To assess the feasibility and clinical value of diffusion tensor imaging and tractography for evaluating chronic spinal cord compression. MATERIAL AND METHODS: Single-shot spin-echo echo-planar DT sequences were scanned in 42 spinal cord compression patients and 49 healthy volunteers. The mean values of the apparent diffusion coefficient and fractional anisotropy were measured in region of interest at the cervical and lower thoracic spinal cord. The patients were divided into two groups according to the high signal on T2WI (the SCC-HI group and the SCC-nHI group for with or without high signal). A one-way ANOVA was used. Diffusion tensor tractography was used to visualize the morphological features of normal and impaired white matter. RESULTS: There were no statistically significant differences in the apparent diffusion coefficient and fractional anisotropy values between the different spinal cord segments of the normal subjects. All of the patients in the SCC-HI group had increased apparent diffusion coefficient values and decreased fractional anisotropy values at the lesion level compared to the normal controls. However, there were no statistically significant diffusion index differences between the SCC-nHI group and the normal controls. In the diffusion tensor imaging maps, the normal spinal cord sections were depicted as fiber tracts that were color-encoded to a cephalocaudal orientation. The diffusion tensor images were compressed to different degrees in all of the patients. CONCLUSION: Diffusion tensor imaging and tractography are promising methods for visualizing spinal cord tracts and can provide additional information in clinical studies in spinal cord compresion.