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Background: The status of the hypothalamic‐pituitary‐gonadal (HPG) axis is important for assessing the onset of physiological or pathological puberty. The reference standard gonadotropin‐releasing hormone (GnRH) stimulation test requires hospital admission and repeated blood samples. A simple noninvasive method would be beneficial. Objectives: To explore a noninvasive method for evaluating HPG axis activation in children using an MRI radiomics model. Study Type: Retrospective. Population: Two hundred thirty‐nine children (83 male; 3.6–14.6 years) with hypophysial MRI and GnRH stimulation tests, randomly divided a training set (168 children) and a test set (71 children). Field Strength/Sequence: 3.0 T, 3D isotropic fast spin echo (CUBE) T1‐weighted imaging (T1WI) sequences. Assessment: Radiomics features were extracted from sagittal 3D CUBE T1WI, and imaging signatures were generated using the least absolute shrinkage and selection operator (LASSO) with 10‐fold cross‐validation. Diagnostic performance for differential diagnosis of HPG status was compared between a radiomics model and MRI features (adenohypophyseal height [aPH] and volume [aPV]). Statistical Tests: Receiver operating characteristic (ROC) and decision curve analysis (DCA). A P value <0.05 was considered statistically significant. Results: Eight hundred fifty‐one radiomics features were extracted and reduced to 10 by the LASSO method in the training cohort. The radiomics model based on CUBE T1WI showed good performance in assessment of HPG axis activation with an area under the ROC curve (AUC) of 0.81 (95% CI: 0.71, 0.91) in the test set. The AUC of the radiomics model was significantly higher than that of aPH (0.81 vs. 0.65) but there was no significant difference compared to aPV (0.81 vs. 0.78, P = 0.58). In DCA analysis, the radiomics signature showed higher net benefit over the aPV and aPH models. Data Conclusions: The MRI radiomics model has potential to assess HPG axis activation status noninvasively, potentially providing valuable information in the diagnosis of patients with pathological puberty onset. Evidence Level: 4 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

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The ongoing epidemic of SARS‐CoV‐2 is taking a substantial financial and health toll on people worldwide. Assessing the level and duration of SARS‐CoV‐2 neutralizing antibody (Nab) would provide key information for government to make sound healthcare policies. Assessed at 3‐, 6‐, 12‐, and 18‐month postdischarge, we described the temporal change of IgG levels in 450 individuals with moderate to critical COVID‐19 infection. Moreover, a data imputation framework combined with a novel deep learning model was implemented to predict the long‐term Nab and IgG levels in these patients. Demographic characteristics, inspection reports, and CT scans during hospitalization were used in this model. Interpretability of the model was further validated with Shapely Additive exPlanation (SHAP) and Gradient‐weighted Class Activation Mapping (GradCAM). IgG levels peaked at 3 months and remained stable in 12 months postdischarge, followed by a significant decline in 18 months postdischarge. However, the Nab levels declined from 6 months postdischarge. By training on the cohort of 450 patients, our long‐term antibody prediction (LTAP) model could predict long‐term IgG levels with relatively high area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, and F1‐score, which far exceeds the performance achievable by commonly used models. Several prognostic factors including FDP levels, the percentages of T cells, B cells and natural killer cells, older age, sex, underlying diseases, and so forth, served as important indicators for IgG prediction. Based on these top 15 prognostic factors identified in IgG prediction, a simplified LTAP model for Nab level prediction was established and achieved an AUC of 0.828, which was 8.9% higher than MLP and 6.6% higher than LSTM. The close correlation between IgG and Nab levels making it possible to predict long‐term Nab levels based on the factors selected by our LTAP model. Furthermore, our model identified that coagulation disorders and excessive immune response, which indicate disease severity, are closely related to the production of IgG and Nab. This universal model can be used as routine discharge tests to identify virus‐infected individuals at risk for recurrent infection and determine the optimal timing of vaccination for general populations. [ABSTRACT FROM AUTHOR]

Background: Noninvasive determination of Notch signaling is important for prognostic evaluation and therapeutic intervention in glioma. Purpose: To predict Notch signaling using multiparametric (mp) MRI radiomics and correlate with biological characteristics in gliomas. Study Type: Retrospective. Population: A total of 63 patients for model construction and 47 patients from two public databases for external testing. Field Strength/Sequence: A 1.5 T and 3.0 T, T1‐weighted imaging (T1WI), T2WI, T2 fluid attenuated inversion recovery (FLAIR), contrast‐enhanced (CE)‐T1WI. Assessment: Radiomic features were extracted from CE‐T1WI, T1WI, T2WI, and T2FLAIR and imaging signatures were selected using a least absolute shrinkage and selection operator. Diagnostic performance was compared between single modality and a combined mpMRI radiomics model. A radiomic–clinical nomogram was constructed incorporating the mpMRI radiomic signature and Karnofsky Performance score. The performance was validated in the test set. The radiomic signatures were correlated with immunohistochemistry (IHC) analysis of downstream Notch pathway components. Statistical Tests: Receiver operating characteristic curve, decision curve analysis (DCA), Pearson correlation, and Hosmer–Lemeshow test. A P value < 0.05 was considered statistically significant. Results: The radiomic signature derived from the combination of all sequences numerically showed highest area under the curve (AUC) in both training and external test sets (AUCs of 0.857 and 0.823). The radiomics nomogram that incorporated the mpMRI radiomic signature and KPS status resulted in AUCs of 0.891 and 0.859 in the training and test sets. The calibration curves showed good agreement between prediction and observation in both sets (P= 0.279 and 0.170, respectively). DCA confirmed the clinical usefulness of the nomogram. IHC identified Notch pathway inactivation and the expression levels of Hes1 correlated with higher combined radiomic scores (r = −0.711) in Notch1 mutant tumors. Data Conclusion: The mpMRI‐based radiomics nomogram may reflect the intratumor heterogeneity associated with downstream biofunction that predicts Notch signaling in a noninvasive manner. Evidence Level: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Objective: Blame attribution (who is to blame for problem causes) and solution attribution (who is to control problem solving) are two critical dimensions of responsibility attribution in psychotherapy. The present study aimed to (1) investigate the impacts of blame attribution and solution attribution on session outcomes from both client and therapist perspectives and (2) clarify the relationship between the therapist–client congruence of responsibility attribution and session outcomes. Method: A total of 69 clients were recruited at a university counselling centre. Client‐rated responsibility attribution (to what extent they were responsible for the causes and solution of their current concerns), therapist‐rated responsibility attribution (to what extent they thought their clients should be responsible for the causes and solution of clients' current concerns), client‐rated session quality and symptom level for each session were collected across 387 sessions. Multilevel regression was used to explore the relationship between responsibility attribution and session outcomes. Truth and bias model and response surface analysis were utilized to analyse the within‐client and between‐client client–therapist congruence effects. Results: The main results included that (1) the clients with higher solution responsibility had more symptom improvement and higher evaluation of session quality (between‐client level). A client's perceived solution responsibility predicted better session quality and fewer next session symptom levels (within‐client level). (2) If a therapist attributed more solution responsibility to his/her client, the session quality was higher (within‐client level). (3) Neither clients' nor therapists' perspectives on blame attribution directly affected session outcomes. But the higher the client's blame for his/her problem causes, the stronger the association between solution responsibility and symptom reduction (within‐client level). (4) Higher within‐client client–therapist congruence on blame responsibility led to better session outcomes. Conclusion: The clients' solution responsibility and client–therapist congruence on blame for problem causes contribute to session outcomes in psychotherapy. [ABSTRACT FROM AUTHOR]

Background: Corticospinal tract (CST) injury has been shown to exert a major influence on functional recovery after ischemic stroke. Purpose To evaluate the prognostic value of CST injury estimated using a recent developed tractometry‐based method. Study Type: Prospective. Population: Forty‐eight patients with CST damage induced by stroke lesion who underwent brain magnetic resonance imaging within 7 days from onset. Sequence Diffusion‐weighted imaging (b = 1000 seconds/mm2) and diffusion kurtosis imaging (DKI) spin‐echo echo‐planar sequence with three b‐values (0, 1250, and 2500 seconds/mm2) at 3.0 T. Assessment A recently developed approach that combines tract segmentation and orientation mapping was used for CST‐specific tractography and tractometry. CST injury was estimated using the proposed method with diffusion metrics extracted from DKI sequence and with the first principal component (PC1) of the metrics. We also calculated the weighted lesion load (wLL) for comparison. Clinical evaluation included the National Institutes of Health Stroke Score in the acute phase and the modified Rankin scale at 3 months post‐stroke. The correlations between CST injury and initial motor impairment, as well as the prognostic values of CST injury for functional outcomes were evaluated. Statistical Tests: Pearson correlation and logistic regression. Area under the receiver operating characteristic curve. P < 0.05 was considered statistically significant. Results: CST injury calculated with diffusion metrics except fractional anisotropy all showed significant correlations with initial motor impairment. PC1 achieved the largest correlation coefficient (R = 0.65) compared with wLL and other diffusion metrics. In addition to wLL, DKI_AK, AFD_total, and PC1 maximum all showed predictive values for functional outcomes. Data Conclusion: Structural injury to CST is important for the assessment of the extent of injury and the prediction of functional outcome. The method proposed in our study could provide an imaging indicator to quantify the CST injury after ischemic stroke. Level of Evidence: 2 Technical Efficacy: Stage 1 [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the feasibility of using a continuous‐time random‐walk (CTRW) diffusion model, together with a quartile histogram analysis, for assessing glioma malignancy by probing tissue heterogeneity as well as cellularity. In this prospective study, 91 patients (40 females, 51 males) with histopathologically proven gliomas underwent MRI at 3 T. The cohort included 42 grade II (GrII), 19 grade III (GrIII) and 29 grade IV (GrIV) gliomas. Echo‐planar diffusion‐weighted imaging was conducted using 17 b‐values (0–4000 s/mm2). Three CTRW model parameters, including an anomalous diffusion coefficient Dm, and two parameters related to temporal and spatial diffusion heterogeneity α and β, respectively, were obtained. The mean parameter values within the tumor regions of interest (ROIs) were computed by utilizing the first quartile of the histograms as well as the full ROI for comparison. A Bonferroni–Holm‐corrected Mann–Whitney U‐test was used for the group comparisons. Individual and combinations of the CTRW parameters were evaluated for the characterization of gliomas with a receiver operating characteristic analysis. All first‐quartile mean CTRW parameters yielded significant differences (p‐values < 0.05) between pair‐wise comparisons of GrII (Dm: 1.14 ± 0.37 μm2/ms; α: 0.904 ± 0.03, β: 0.913 ± 0.06), GrIII (Dm: 0.88 ± 0.21 μm2/ms; α: 0.888 ± 0.01, β: 0.857 ± 0.06) and GrIV gliomas (Dm: 0.73 ± 0.22 μm2/ms; α: 0.878 ± 0.01; β: 0.791 ± 0.07). The highest sensitivity, specificity, accuracy and area‐under‐the‐curve of using the combinations of the first‐quartile parameters were 84.2%, 78.5%, 75.4% and 0.76 for GrII and GrIII classification; 86.2%, 89.4%, 75% and 0.76 for GrIII and GrIV classification; and 86.2%, 85.7%, 84.5% and 0.90 for GrII and GrIV classification, respectively. Quartile‐based analysis produced higher accuracy and area‐under‐the‐curve than the full ROI‐based analysis in all classifications. The CTRW diffusion model, together with a quartile‐based histogram analysis, offers a new way for probing tumor structural heterogeneity at a subvoxel level, and has potential for in vivo assessment of glioma malignancy to complement histopathology. [ABSTRACT FROM AUTHOR]

Although emerging data demonstrated mortality of young COVID‐19 patients, no data have reported the risk factors of mortality for these young patients, and whether obesity is a risk for young COVID‐19 patients remains unknown. We conducted a retrospective study including 13 young patients who died of COVID‐19 and 40 matched survivors. Logistic regression was employed to characterize the risk factors of mortality in young obese COVID‐19 patients. Most of the young deceased COVID‐19 patients were mild cases at the time of admission, but the disease progressed rapidly featured by a higher severity of patchy shadows (100.00% vs 48.70%; P =.006), pleural thickening (61.50% vs 12.80%; P =.012), and mild pericardial effusion (76.90% vs 0.00%; P <.001). Most importantly, the deceased patients manifested higher body mass index (odds ratio [OR] = 1.354; 95% confidence interval [CI] = 1.075‐1.704; P =.010), inflammation‐related index C‐reactive protein (OR = 1.014; 95% CI = 1.003‐1.025; P =.014), cardiac injury biomarker hs‐cTnI (OR = 1.420; 95% CI = 1.112‐1.814; P =.005), and increased coagulation activity biomarker D‐dimer (OR = 418.7; P =.047), as compared with that of survivors. Our data support that obesity could be a risk factor associated with high mortality in young COVID‐19 patients, whereas aggravated inflammatory response, enhanced cardiac injury, and increased coagulation activity are likely to be the mechanisms contributing to the high mortality. [ABSTRACT FROM AUTHOR]

Purpose: The human brain has two cerebral hemispheres that are roughly symmetric and separated by a midline, which is nearly a straight line shown in axial computed tomography (CT) images in healthy subjects. However, brain diseases such as hematoma and tumors often cause midline shift, where the degree of shift can be regarded as a quantitative indication in clinical practice. To facilitate clinical evaluation, we need computer‐aided methods to automate this quantification. Nevertheless, most existing studies focused on the landmark‐ or symmetry‐based methods that provide only the existence of shift or its maximum distance, which could be easily affected by anatomical variability and large brain deformations. Intuitive results such as midline delineation or measurement are lacking. In this study, we focus on developing an automated and robust method based on the fully convolutional neural network for the delineation of midline in largely deformed brains. Methods: We propose a novel regression‐based line detection network (RLDN) for the robust midline delineation, especially in largely deformed brains. Specifically, to improve the robustness of delineation in largely deformed brains, we regard the delineation of the midline as the skeleton extraction task and then use the multiscale bidirectional integration module to acquire more representative features. Based on the skeleton extraction, we incorporate the regression task into it to delineate more accurate and continuous midline, especially in largely deformed brains. Our study utilized the public CQ 500 dataset (128 subjects) for training with hold‐out validation on 61 subjects from a private cohort accrued from a local hospital. Results: The mean line distance error and F1‐score were 1.17 ± 0.72 mm with 0.78 on CQ 500 test set, and 4.15 ± 3.97 mm with 0.61 on the private dataset. Besides, significant differences (P < 0.05) were observed between our method and other comparative ones on these two datasets. Conclusions: This work provides a novel solution to acquire robust delineation of the midline, especially in largely deformed brains, and achieves state‐of‐the‐art performance on the public and our private dataset, which makes it possible for automated diagnosis of relevant brain diseases in the future. [ABSTRACT FROM AUTHOR]

Background: Previous studies have found widespread impairment of white matter (WM) integrity and disruption of structural network connectivity in cerebral small-vessel disease, but have not evaluated these changes jointly in nondemented patients.Purpose: To jointly investigate the microstructural impairment of WM and the related alterations of structural network topology in nondemented cerebral small-vessel disease (CSVD-ND).Study Type: Prospective.Population: Thirty-seven CSVD-ND patients and 34 elderly controls, who were age-, sex-, and education-matched.Field Strength/sequence: 3.0T/diffusion tensor imaging (DTI).Assessment: Clinical characteristics, lacunar infarct, and white matter hyperintensity (WMH) was assessed. A multiatlas likelihood fusion (MALF) algorithm was used for DTI-based brain segmentation and network node defining. Then the alterations of WM integrity and structural network topology were investigated jointly.Statistical Tests: Student's t-test, chi-square test, Mann-Whitney U-test, linear regression, Pearson correlation, and multiple comparison correction.Results: Decreased fractional anisotropy and increased trace values were observed in predefined structures (P < 0.05, familywise error rate-corrected), including major commissural fibers, projection fibers, and some association fibers. Topologically, both groups showed small-worldness. CSVD-ND patients showed reduced global and local efficiency (P < 0.001). Despite widespread impairment of WM integrity, CSVD-ND patients only showed reduced nodal efficiency in the right superior occipital gyrus and the right lingual gyrus (P < 0.05, familywise error rate-corrected). The nodal local efficiency of the right precuneus was associated with the processing speed after adjusting the effect of lacunar infarct and WMH (r = -0.499, P = 0.038).Data Conclusion: WM integrity was widely impaired in nondemented CSVD patients but structural network connectivity was relatively preserved. DTI may potentially provide information for the pathophysiology of CSVD in the nondemented phase.Level Of Evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:1162-1169. [ABSTRACT FROM AUTHOR]

The present study examined the relationships among attention to emotion, emotional clarity, emotion regulation, and job satisfaction, and tested whether the plausible associations between emotional processes (e.g., attention to emotion, emotional clarity) and job satisfaction can be mediated by emotion regulation in a sample of Chinese medical staff. In total, 1,766 medical staff in Guangdong province completed questionnaires including the demographics, the Minnesota Satisfaction Questionnaire, Emotional Clarity, Attention to Emotion, and the Emotion Regulation Questionnaire. Results showed significant direct effect of emotional clarity, but not attention to emotion on job satisfaction. Cognitive reappraisal significantly mediated the associations between emotional processes (e.g., attention to emotion, emotional clarity) and job satisfaction whereas expressive suppression was not a statistically significant mediator. These results suggest that attention to emotion and emotional clarity contribute to job satisfaction by increasing certain emotion regulation strategies such as reappraisal. Intervention or medical education programs targeting enhancing emotional clarity and reappraisal may be beneficial for increasing job satisfaction of medical staff in China. [ABSTRACT FROM AUTHOR]

Background: Diffusion-tensor-imaging (DTI) is sensitive in detecting white matter changes in type-2 diabetes mellitus (T2DM). However, DTI indices can be affected by either neurite density or spatial variation. A novel diffusion MRI technique, termed neurite orientation dispersion and density imaging (NODDI), can provide distinct indices of fiber density and dispersion.Purpose: To characterize brain microstructural alterations in T2DM patients with mild cognitive impairment (MCI) using the NODDI model.Study Type: Cross-sectional.Subjects: Twenty T2DM patients with (DM-MCI group), 18 age- and gender-matched T2DM patients with normal cognition (DM-NC group), and 28 euglycemic healthy controls (HC).Field Strength/sequence: 3T/NODDI.Assessment: Diffusion data were analyzed using tract-based-spatial-statistics (TBSS) analysis in white matter and voxel-based analysis in both white and gray matter. NODDI indices, including intracellular volume fraction (Vic) and orientation dispersion index (ODI), were estimated from multiple regions and compared among these groups.Statistical Tests: Differences between groups were compared by Student's t-test, Pearson chi-square test, or analysis of variance when appropriate. Correlation analyses were performed to investigate the relationship between NODDI variables and clinical measurements.Results: Whole-brain TBSS revealed that 2.29% and 2.02% of the white matter regions exhibited decreased fractional anisotropy and Vic, respectively, between the DM-NC and HC, while considerably larger white matter areas showed decreased fractional anisotropy (38.38%) and Vic (34.64%) between the DM-MCI and HC (Student's t-test, P < 0.05). However, the angular variation of neurites, characterized by ODI, exhibited very little (0.1%, P < 0.05) or no difference (P > 0.05) between either the DM-MCI or DM-NC groups and HC. Decreased Vic values in the genu of the corpus callosum (R = 0.580, 0.551 and 0.586, P < 0.01) and thalamus (R = 0.570, 0.616, and 0.595, P < 0.05) correlated with glycosylated hemoglobin A1c level, disease duration, and neuropsychological scores, respectively.Data Conclusion: T2DM patients with cognitive decline had reduced Vic, which indicated decreased density of axons and dendrites. NODDI might be able to help probe microstructural changes in white and gray matter and provide information on diabetic encephalopathy, including those with cognitive impairment.Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:889-898. [ABSTRACT FROM AUTHOR]

Purpose To demonstrate the capability of the fractional motion (FM) model for describing anomalous diffusion in cerebral gliomas and to assess the potential feasibility of FM for grading these tumors. Methods Diffusion MRI images were acquired from brain tumor patients using a special Stejskal-Tanner diffusion sequence with variable diffusion gradient amplitudes and separation times. Patients with histopathologically confirmed gliomas, including astrocytic and oligoastrocytic tumors, were selected. The FM-related parameters, including the Noah exponent ( [ABSTRACT FROM AUTHOR]

Purpose: To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery.Materials and Methods: In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA.Results: Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]).Conclusion: As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted.Level Of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1045-1052. [ABSTRACT FROM AUTHOR]

Quantitative susceptibility mapping (QSM) has enabled magnetic resonance imaging (MRI) of tissue magnetic susceptibility to advance from simple qualitative detection of hypointense blooming artifacts to precise quantitative measurement of spatial biodistributions. QSM technology may be regarded to be sufficiently developed and validated to warrant wide dissemination for clinical applications of imaging isotropic susceptibility, which is dominated by metals in tissue, including iron and calcium. These biometals are highly regulated as vital participants in normal cellular biochemistry, and their dysregulations are manifested in a variety of pathologic processes. Therefore, QSM can be used to assess important tissue functions and disease. To facilitate QSM clinical translation, this review aims to organize pertinent information for implementing a robust automated QSM technique in routine MRI practice and to summarize available knowledge on diseases for which QSM can be used to improve patient care. In brief, QSM can be generated with postprocessing whenever gradient echo MRI is performed. QSM can be useful for diseases that involve neurodegeneration, inflammation, hemorrhage, abnormal oxygen consumption, substantial alterations in highly paramagnetic cellular iron, bone mineralization, or pathologic calcification; and for all disorders in which MRI diagnosis or surveillance requires contrast agent injection. Clinicians may consider integrating QSM into their routine imaging practices by including gradient echo sequences in all relevant MRI protocols.Level Of Evidence: 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:951-971. [ABSTRACT FROM AUTHOR]

In this article, we present a unified statistical pipeline for analyzing the white matter (WM) tracts morphometry and microstructural integrity, both globally and locally within the same WM tract, from diffusion tensor imaging. Morphometry is quantified globally by the volumetric measurement and locally by the vertexwise surface areas. Meanwhile, microstructural integrity is quantified globally by the mean fractional anisotropy (FA) and trace values within the specific WM tract and locally by the FA and trace values defined at each vertex of its bounding surface. The proposed pipeline consists of four steps: (1) fully automated segmentation of WM tracts in a multi-contrast multi-atlas framework; (2) generation of the smooth surface representations for the WM tracts of interest; (3) common template surface generation on which the localized morphometric and microstructural statistics are defined and a variety of statistical analyses can be conducted; (4) multiple comparison correction to determine the significance of the statistical analysis results. Detailed herein, this pipeline has been applied to the corpus callosum in Alzheimer's disease (AD) with significantly decreased FA values and increased trace values, both globally and locally, being detected in patients with AD when compared to normal aging populations. A subdivision of the corpus callosum in both hemispheres revealed that the AD pathology primarily affects the body and splenium of the corpus callosum. Validation analyses and two multiple comparison correction strategies are provided. Hum Brain Mapp 38:1875-1893, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To explore the usefulness of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) derived from reduced field-of-view (r-FOV) diffusion-weighted imaging (DWI) in differentiating malignant and benign thyroid nodules and stratifying papillary thyroid cancer (PTC) with aggressive histological features.Materials and Methods: This Institutional Review Board-approved, retrospective study included 93 patients with 101 pathologically proven thyroid nodules. All patients underwent preoperative r-FOV DWI at 3T. The whole-lesion ADC assessments were performed for each patient. Histogram-derived ADC parameters between different subgroups (pathologic type, extrathyroidal extension, lymph node metastasis) were compared. Receiver operating characteristic curve analysis was used to determine optimal histogram parameters in differentiating benign and malignant nodules and predicting aggressiveness of PTC.Results: Mean ADC, median ADC, 5th percentile ADC, 25th percentile ADC, 75th percentile ADC, 95th percentile ADC (all P < 0.001), and kurtosis (P = 0.001) were significantly lower in malignant thyroid nodules, and mean ADC achieved the highest AUC (0.919) with a cutoff value of 1842.78 × 10-6 mm2 /s in differentiating malignant and benign nodules. Compared to the PTCs without extrathyroidal extension, PTCs with extrathyroidal extension showed significantly lower median ADC, 5th percentile ADC, and 25th percentile ADC. The 5th percentile ADC achieved the highest AUC (0.757) with cutoff value of 911.5 × 10-6 mm2 /s for differentiating between PTCs with and without extrathyroidal extension.Conclusion: Whole-lesion ADC histogram analysis might help to differentiate malignant nodules from benign ones and show the PTCs with extrathyroidal extension. J. Magn. Reson. Imaging 2016;44:1546-1555. [ABSTRACT FROM AUTHOR]

Purpose: To determine the utility of intravoxel incoherent motion (IVIM) imaging in grading gliomas and compare IVIM perfusion metrics with arterial spin labeling (ASL)-derived cerebral blood flow (CBF).Materials and Methods: Fifty-two patients with pathologically confirmed gliomas underwent IVIM and ASL imaging at 3.0T. IVIM perfusion-related diffusivity (D*), perfusion fraction (f), product of f and D*(f×D*), true diffusivity (D), and apparent diffusion coefficient (ADC) were obtained to distinguish glioma grades. The CBF derived from pseudocontinuous ASL within the solid tumor was compared and correlated with IVIM perfusion metrics for grading of gliomas. Values were also normalized to the contralateral normal-appearing white matter. Receiver-operating characteristic was performed to determine diagnostic efficiency. The reliability was estimated with intraclass coefficient, coefficient of variance, and Bland-Altman plots.Results: IVIM perfusion metrics and CBF were significantly higher in the high-grade than the low-grade gliomas (P < 0.001), ADC and D were significantly lower in the high-grade than the low-grade gliomas (P < 0.001). f×D* differed significantly between grades II through IV (P < 0.05 for all). The other metrics showed significant difference between grade II and grade III (P < 0.05 for all). Area under the curve (AUC) was largest for f×D* in distinguishing high-grade from low-grade gliomas (AUC = 0.979, P < 0.001) and between grade II and grade III (AUC = 0.957, P < 0.001). f×D* improved diagnostic performance of CBF in grading gliomas and showed strong correlation with CBF (r = 0.696, P < 0.001).Conclusion: IVIM-derived metrics are promising biomarkers in preoperative grading gliomas. IVIM imaging may be an additive method to ASL and ADC for evaluating tumor perfusion and diffusion. J. Magn. Reson. Imaging 2016;44:620-632. [ABSTRACT FROM AUTHOR]

Purpose: To measure the longitudinal change in multiple sclerosis (MS) lesion susceptibility using quantitative susceptibility mapping (QSM).Materials and Methods: The study was approved by our Institutional Review Board. Longitudinal changes in quantitative susceptibility values of new enhanced-with-Gd MS lesions were measured at baseline magnetic resonance imaging (MRI) and on a follow-up MRI in 29 patients within 2 years using a 3D multiple echo gradient echo sequence on a 3T scanner. Paired t-test and the generalized estimating equations (GEE) model was used to analyze the longitudinal change.Results: Lesion susceptibility values relative to normal-appearing white matter (NAWM) changed from 3.61 ± 6.11 ppb when enhanced-with-Gd at the baseline MRI to 20.42 ± 10.23 ppb when not-enhanced-with-Gd at the follow-up MRI (P < 0.001).Conclusion: MS lesion susceptibility value increases significantly as the lesion evolves from enhanced-with-Gd to not-enhanced-with-Gd, serving as a disease biomarker. J. Magn. Reson. Imaging 2016;44:426-432. [ABSTRACT FROM AUTHOR]

To find imaging signs of active degenerative processes in vanishing white matter disease (VWM), six VWM patients and six matched controls underwent MR examinations. The data were analyzed with modified Scheltens scales for morphological findings and determined quantitatively for apparent diffusion coefficient (ADC). Single-voxel MR spectra were acquired at the parietal white matter and analyzed with LCModel. Typical VWM brain lesions were found in all patients accompanied by proton diffusion abnormalities: Increased ADC appeared in brain regions with severe myelin destruction in all patients, and reduced ADC in two of six younger patients in remaining white matter adjacent to the lesions or at the borders around the lesions, who had a short history of the disease (≤ 1 year). The MR spectroscopy revealed reductions of NAA, Cho, and Cr, which correlate to the grade of white matter abnormalities. An increase of myo-inositol as marker of reactive gliosis was missing. Thus, restricted proton diffusion was evident in younger VWM patients with short history of disease, which in combination with lack of reactive gliosis may reflect early white matter degeneration in VWM. The multimodal MR methods are useful for characterizing such tissue degeneration in brain in vivo. J. Magn. Reson. Imaging 2012;35:926-932. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objective: Most patients with stroke casued by middle cerebral artery occlusion (MCAO) show cognitive deficit that is generally regarded as resulting from damage to the cerebral cortex rather than the hippocampus. Whether MCAO induces hippocampal damage and whether this contributes to the cognitive defects remains unclear. Here we investigate the hippocampal damage and its correlation to cognitive defects after exclusively unilateral MCAO and the underlying mechanism for that damage. Methods: Patients were assessed for hippocampal damage by magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), and the Mini Mental-Status Evaluation (MMSE) and Rey Auditory Verbal Learning Test (RAVLT) were used to assess for cognitive defects. Results: We provide the first evidence that patients with exclusively unilateral MCAO showed hippocampal damage characterized by an infarct-size-independent atrophy and alterations in neuronal and glial metabolites in the ipsilateral hippocampus, in parallel with cognitive impairment. Rodent MCAO also induced delayed shrinkage and pyramidal neuronal death in the ipsilateral hippocampus and an impairment of hippocampal-dependent spatial memory. Blocking Gap junctional communication (GJC) with carbenoxolone or downregulation of connexin43 (Cx43) significantly increased the survival of the pyramidal neurons in the ipsilateral hippocampus and improved behavioral scores. Furthermore, Cx43 heterozygous mice showed reduced shrinkage and metabolite abnormality in ipsilateral hippocampus after MCAO. Interpretation: Astroglial GJC plays a significant role in MCAO-induced remote hippocampal damage and cognitive impairment. It might be possible to improve the cognition in patients with MCAO by manipulating interastrocytic communication via the gap junction channels. ANN NEUROL 2011; [ABSTRACT FROM AUTHOR]