Shorter TR combined with finer atlas positively modulate topological organization of brain network: A resting state fMRI study.

BACKGROUND: The use of shorter TR and finer atlases in rs-fMRI can provide greater detail on brain function and anatomy. However, there is limited understanding of the effect of this combination on brain network properties. METHODS: A study was conducted with 20 healthy young volunteers who underwent rs-fMRI scans with both shorter (0.5s) and long (2s) TR. Two atlases with different degrees of granularity (90 vs 200 regions) were used to extract rs-fMRI signals. Several network metrics, including small-worldness, Cp, Lp, Eloc, and Eg, were calculated. Two-factor ANOVA and two-sample t-tests were conducted for both the single spectrum and five sub-frequency bands. RESULTS: The network constructed using the combination of shorter TR and finer atlas showed significant enhancements in Cp, Eloc, and Eg, as well as reductions in Lp and γ in both the single spectrum and subspectrum (p < 0.05, Bonferroni correction). Network properties in the 0.082-0.1 Hz frequency range were weaker than those in the 0.01-0.082 Hz range. CONCLUSION: Our findings suggest that the use of shorter TR and finer atlas can positively affect the topological characteristics of brain networks. These insights can inform the development of brain network construction methods.

Molecular subtyping of diffuse gliomas using magnetic resonance imaging: comparison and correlation between radiomics and deep learning.

OBJECTIVES: The molecular subtyping of diffuse gliomas is important. The aim of this study was to establish predictive models based on preoperative multiparametric MRI. METHODS: A total of 1016 diffuse glioma patients were retrospectively collected from Beijing Tiantan Hospital. Patients were randomly divided into the training (n = 780) and validation (n = 236) sets. According to the 2016 WHO classification, diffuse gliomas can be classified into four binary classification tasks (tasks I-IV). Predictive models based on radiomics and deep convolutional neural network (DCNN) were developed respectively, and their performances were compared with receiver operating characteristic (ROC) curves. Additionally, the radiomics and DCNN features were visualized and compared with the t-distributed stochastic neighbor embedding technique and Spearman's correlation test. RESULTS: In the training set, areas under the curves (AUCs) of the DCNN models (ranging from 0.99 to 1.00) outperformed the radiomics models in all tasks, and the accuracies of the DCNN models (ranging from 0.90 to 0.94) outperformed the radiomics models in tasks I, II, and III. In the independent validation set, the accuracies of the DCNN models outperformed the radiomics models in all tasks (0.74-0.83), and the AUCs of the DCNN models (0.85-0.89) outperformed the radiomics models in tasks I, II, and III. DCNN features demonstrated more superior discriminative capability than the radiomics features in feature visualization analysis, and their general correlations were weak. CONCLUSIONS: Both the radiomics and DCNN models could preoperatively predict the molecular subtypes of diffuse gliomas, and the latter performed better in most circumstances. KEY POINTS: • The molecular subtypes of diffuse gliomas could be predicted with MRI. • Deep learning features tend to outperform radiomics features in large cohorts. • The correlation between the radiomics features and DCNN features was low.

Predicting EGFR mutation status in lung adenocarcinoma presenting as ground-glass opacity: utilizing radiomics model in clinical translation.

OBJECTIVES: This study aimed to establish a non-invasive radiomics model based on computed tomography (CT), with favorable sensitivity and specificity to predict EGFR mutation status in GGO-featured lung adenocarcinoma subsequently guiding the administration of targeted therapy. METHODS: Clinical-pathological information and preoperative CT images of 636 lung adenocarcinoma patients (464, 100, and 72 in the training, internal, and external validation sets, respectively) that underwent GGO lesions resection were included. A total of 1476 radiomics features were extracted with gradient boosting decision tree (GBDT). RESULTS: The established radiomics model containing 102 selected features showed an encouraging discrimination performance of EGFR mutation status (mutant or wild type), and the predictive ability was superior to that of the clinical model (AUC: 0.838 vs. 0.674, 0.822 vs. 0.730, and 0.803 vs. 0.746 for the training, internal validation, and external validation sets, respectively). The combined radiomics plus clinical model showed no additional benefit over the radiomics model in predicting EGFR status (AUC: 0.846 vs. 0.838, 0.816 vs. 0.822, and 0.811 vs. 0.803, respectively, in three cohorts). Uniquely, this model was validated in a cohort of lung adenocarcinoma patients who have undertaken adjuvant EGFR-TKI treatment and harbored unresected GGOs during the medication, leading to a significantly improved potency of EGFR-TKIs (response rate: 25.9% vs. 53.8%, p = 0.006; before and after prediction, respectively). CONCLUSION: This presented radiomics model can be served as a non-invasive and time-saving approach for predicting the EGFR mutation status in lung adenocarcinoma presenting as GGO. KEY POINTS: • We developed a GGO-specific radiomics model containing 102 radiomics features for EGFR mutation status differentiation. • An AUC of 0.822 and 0.803 in the internal and external validation cohorts, respectively, were achieved. • The radiomics model was utilized in clinical translation in an adjuvant EGFR-TKI treatment cohort with unresected GGOs. A significant improvement in the potency of EGFR-TKIs was achieved (response rate: 25.9% vs. 53.8%, p = 0.006; before and after prediction).

Assessment of Changes in the Cesarean Scar and Uterus Between One and Two Years after Cesarean Section Using 3D T2w SPACE MRI.

Objective To evaluate changes in morphology of the cesarean scar and uterus between one and two years after cesarean section using high-resolution, three dimensional T2-weighted sampling perfection with application optimized contrast using different flip angle evolutions Magnetic Resonance Imaging (3D T2w SPACE MRI). Methods This prospective study was performed to investigate morphological changes in the cesarean scars and uterus from one to two years after cesarean section using high-resolution, 3D T2w SPACE MRI. The healthy volunteers having no childbearing history were recruited as the controls. All data were measured by two experienced radiologists. All data with normal distribution between the one-year and two-year groups were compared using a paired-sample t test or independent t test. Results Finally, 46 women took a pelvic MR examination one year after cesarean section, and a subset of 15 completed the same examination again after two years of cesarean section. Both the uterine length and the anterior wall thickness after two years of cesarean section (5.75 ± 0.46 and 1.45 ± 0.35 cm) were significantly greater than those measured at one year (5.33 ± 0.59 and 1.25 ± 0.27 cm) (t = -2.363 and -2.175, P= 0.033 and 0.048). No significant difference was shown in myometrial thickness two years after cesarean section (1.45 ±0.35 cm) with respect to the control group (1.58 ± 0.21 cm, P= 0.170). Nine women who underwent MRI twice were considered to have scar diverticula one year after cesarean section, and still had diverticula two years after cesarean section. The thickness, height, and width of the uterine scar showed no significant change from one to two years (all P > 0.05). Conclusions 3D T2w SPACE MRI provides overall morphologic details and shows dynamic changes in the scar and the uterus between one and two years after cesarean section. Scar morphology after cesarean section reached relatively stable one year after cesarean section, and uterine morphology was closer to normal two years after cesarean section.

Genome-wide cell-free DNA methylation analyses improve accuracy of non-invasive diagnostic imaging for early-stage breast cancer.

Early detection is crucial to improve breast cancer (BC) patients' outcomes and survival. Mammogram and ultrasound adopting the Breast Imaging Reporting and Data System (BI-RADS) categorization are widely used for BC early detection, while suffering high false-positive rate leading to unnecessary biopsy, especially in BI-RADS category-4 patients. Plasma cell-free DNA (cfDNA) carrying on DNA methylation information has emerged as a non-invasive approach for cancer detection. Here we present a prospective multi-center study with whole-genome bisulfite sequencing data to address the clinical utility of cfDNA methylation markers from 203 female patients with breast lesions suspected for malignancy. The cfDNA is enriched with hypo-methylated genomic regions. A practical computational framework was devised to excavate optimal cfDNA-rich DNA methylation markers, which significantly improved the early diagnosis of BI-RADS category-4 patients (AUC from 0.78-0.79 to 0.93-0.94). As a proof-of-concept study, we performed the first blood-based whole-genome DNA methylation study for detecting early-stage breast cancer from benign tumors at single-base resolution, which suggests that combining the liquid biopsy with the traditional diagnostic imaging can improve the current clinical practice, by reducing the false-positive rate and avoiding unnecessary harms.

Visualization of lenticulostriate artery by intracranial dark-blood vessel wall imaging and its relationships with lacunar infarction in basal ganglia: a retrospective study.

OBJECTIVES: There is close relationship between lenticulostriate arteries (LSAs) and lacunar infarctions (LIs) of the basal ganglia. The study aims to visualize the LSAs using high-resolution vessel wall imaging (VWI) on 3T system and explore the correlation between LSAs and LIs. METHODS: Fifty-six patients with LIs in basal ganglia, and 44 age-matched control patients were enrolled and analyzed retrospectively. The raw VWI images were reformatted into coronal slices in minimum intensity projection for further observation of LSAs. The risk factors of LIs in basal ganglia were analyzed by univariate and multivariate logistic regression. The correlation and linear regression analysis between the LSAs and LIs, ipsilateral MCA-M1 plaques were investigated. RESULTS: The total number (p < 0.01) and length (p < 0.01) of LSAs were statistically different between basal ganglias with and without LIs. The total number of LSAs and ipsilateral MCA-M1 plaques were independently related to LIs in basal ganglias. The mean length of LSAs were negatively correlated with number (r = - 0.33, p = 0.002) and volume (r = - 0.37, p = 0.001) of LIs. Age, drinking history, and mean length of LSAs were associated with LI occurrence in basal ganglia, and mean length of LSAs was correlated with larger volume of LIs. CONCLUSIONS: Number of LSA reduction and ipsilateral MCA-M1 plaques were associated with the presence of LIs in basal ganglias. Age increasing, drinking history, and shorter LSAs were correlated with the increasing of LIs. KEY POINTS: • Patients with LIs tend to have shorter LSAs. • The characteristics of LSAs and ipsilateral MCA-M1 plaques are associated with LIs in basal ganglias. • Age, drinking history, and mean length of LSAs are correlated with LI features in basal ganglias.

Reproducibility of volume and asymmetry measurements of hippocampus, amygdala, and entorhinal cortex on traveling volunteers: a multisite MP2RAGE prospective study.

BACKGROUND: Multisite studies can considerably increase the pool of normally aging individuals with neurodegenerative disorders and thereby expedite the associated research. Understanding the reproducibility of the parameters of related brain structures-including the hippocampus, amygdala, and entorhinal cortex-in multisite studies is crucial in determining the impact of healthy aging or neurodegenerative diseases. PURPOSE: To estimate the reproducibility of the fascinating structures by automatic (FreeSurfer) and manual segmentation methods in a well-controlled multisite dataset. MATERIAL AND METHODS: Three traveling individuals were scanned at 10 sites, which were equipped with the same equipment (3T Prisma Siemens). They used the same scan protocol (two inversion-contrast magnetization-prepared rapid gradient echo sequences) and operators. Validity coefficients (intraclass correlations coefficient [ICC]) and spatial overlap measures (Dice Similarity Coefficient [DSC]) were used to estimate the reproducibility of multisite data. RESULTS: ICC and DSC values varied substantially among structures and segmentation methods, and values of manual tracing were relatively higher than the automated method. ICC and DSC values of structural parameters were greater than 0.80 and 0.60 across sites, as determined by manual tracing. Low reproducibility was observed in the amygdala parameters by automatic segmentation method (ICC = 0.349-0.529, DSC = 0.380-0.873). However, ICC and DSC scores of the hippocampus were higher than 0.60 and 0.65 by two segmentation methods. CONCLUSION: This study suggests that a well-controlled multisite study could provide a reliable MRI dataset. Manual tracing of volume assessments is recommended for low reproducibility structures that require high levels of precision in multisite studies.

Human cortical networking by probabilistic and frequency-specific coupling.

Large-scale cortical networking patterns have been established based on the correlation of slow fluctuations of resting fMRI signals. However, the electrophysiological mechanism of cortical networking remained to be elucidated. With large-scale human ECoG recording, we developed a novel approach for functional network parcellation on the basis of probabilistic co-activation of cortical sites in spatio-temporal microstates. The parcellated networks were verified by electrical cortical stimulation (ECS) and somatosensory evoked potentials recording, which showed significantly higher accuracy than the traditional long-term correlation method. This provides direct electrophysiological evidence supporting the dynamic nature of cortical networking. Further analysis revealed that the brain-wide connectivity is likely established on the coupling of ECoG power envelop over a common carrier frequency ranging from alpha to low-beta (8-32Hz). Surprisingly, the cortical networking pattern over this specific frequency was found to be consistent across various tasks, which resembles the resting networks. The high similarity between the above functional network parcellation and the fMRI resting network atlas in individuals also suggested the slow power-envelope coupling of band-limited neural oscillations as the electrophysiological basis of spontaneous BOLD signals. Collectively, our findings on direct human recording revealed a probabilistic and frequency specific coupling mechanism for large-scale cortical networking shared by task and resting brain.

Development and validation of an artificial intelligence system for grading colposcopic impressions and guiding biopsies.

BACKGROUND: Colposcopy diagnosis and directed biopsy are the key components in cervical cancer screening programs. However, their performance is limited by the requirement for experienced colposcopists. This study aimed to develop and validate a Colposcopic Artificial Intelligence Auxiliary Diagnostic System (CAIADS) for grading colposcopic impressions and guiding biopsies. METHODS: Anonymized digital records of 19,435 patients were obtained from six hospitals across China. These records included colposcopic images, clinical information, and pathological results (gold standard). The data were randomly assigned (7:1:2) to a training and a tuning set for developing CAIADS and to a validation set for evaluating performance. RESULTS: The agreement between CAIADS-graded colposcopic impressions and pathology findings was higher than that of colposcopies interpreted by colposcopists (82.2% versus 65.9%, kappa 0.750 versus 0.516, p < 0.001). For detecting pathological high-grade squamous intraepithelial lesion or worse (HSIL+), CAIADS showed higher sensitivity than the use of colposcopies interpreted by colposcopists at either biopsy threshold (low-grade or worse 90.5%, 95% CI 88.9-91.4% versus 83.5%, 81.5-85.3%; high-grade or worse 71.9%, 69.5-74.2% versus 60.4%, 57.9-62.9%; all p < 0.001), whereas the specificities were similar (low-grade or worse 51.8%, 49.8-53.8% versus 52.0%, 50.0-54.1%; high-grade or worse 93.9%, 92.9-94.9% versus 94.9%, 93.9-95.7%; all p > 0.05). The CAIADS also demonstrated a superior ability in predicting biopsy sites, with a median mean-intersection-over-union (mIoU) of 0.758. CONCLUSIONS: The CAIADS has potential in assisting beginners and for improving the diagnostic quality of colposcopy and biopsy in the detection of cervical precancer/cancer.

Decreased level of peripheral CD8+CD28+ T cells is associated with lymph node metastasis in patients with breast cancer.

Background: Lymph node metastasis (LNM) is an independent risk factor for prognosis in patients with early breast cancer (EBC). Here we explored whether peripheral lymphocyte subtypes could be used as surrogate markers for LNM in patients with EBC. Materials & methods: The lymphocyte subpopulations in peripheral blood were measured in 152 EBC patients and 43 patients with benign breast tumors. Results: The cytotoxic T cell count was significantly lower in patients with EBC than in patients with benign tumors (244.17 ± 105.83 vs 289.97 ± 121.72; p = 0.02), especially in patients with LNM (218.36 ± 86.21; p = 0.04). Conclusion: A decreased level of peripheral CD8+CD28+ T lymphocytes is associated with LNM in patients with EBC and could be used as a potential therapeutic target for breast cancer.

Detecting perfusion deficit in Alzheimer's disease and mild cognitive impairment patients by resting-state fMRI.

BACKGROUND: Vascular factors contributing to cerebral hypoperfusion are implicated in the risk of developing Alzheimer's disease (AD). PURPOSE: To investigate the time-shift mapping created time-shift value of the brain by resting-state functional magnetic resonance imaging (rs-fMRI), and to determine the differences in time-shift value among AD, mild cognitive impairment (MCI), and normal control (NC) groups to better understand the disease. STUDY TYPE: Prospective. SUBJECTS: Twenty-four AD, 24 MCI, and 24 age-matched NC participants. FIELD STRENGTH/SEQUENCE: T2 *-weighted single-shot echo-planar imaging sequence was performed at 3T. In addition, a T1 -weighted fast spoiled gradient-echo sequence was acquired for coregistration. ASSESSMENT: The brain time-shift value was determined from rs-fMRI-based blood oxygenation level-dependent (BOLD) signal in the three groups by time-shift mapping. The perfusion patterns were also investigated in the NC group. STATISTICAL TESTS: One-way analysis of variance and chi-squared tests were used to compare demographic information. The normalized time-shift maps were analyzed in a second-level test using SPM8. All analyses were evaluated with a significance level of P < 0.05 after false discovery rate (FDR) correction. RESULTS: The time-shift maps obtained from rs-fMRI are consistent with the cerebral blood supply atlas. Compared with NC, both MCI and AD groups had less early perfusion arrival areas among the whole brain. In the delayed time-shift value for the AD group, the areas were located in the bilateral precuneus, the sensory-motor cortex in the left hemisphere, and the bilateral calcarine sulcus, which were different from the MCI group (both P < 0.05, FDR corrected). DATA CONCLUSION: The time-shift mapping method could detect perfusion deficits in AD and MCI noninvasively. The perfusion deficits detected by rs-fMRI may provide new insight for understanding the mechanism of neurodegeneration. Level of Evidence 2 Technical Efficacy Stage 3 J. Magn. Reson. Imaging 2019;49:1099-1104.

Increased iron deposition of deep cerebral gray matter structures in hemodialysis patients: A longitudinal study using quantitative susceptibility mapping.

BACKGROUND: The cerebral iron overload in hemodialysis patients has been reported in a previous study, in which the evaluation of the changes in iron content could be affected by the cross-sectional analysis. PURPOSE: To investigate the longitudinal changes of iron deposition in hemodialysis patients using quantitative susceptibility mapping (QSM) and correlate these findings with the longitudinal changes of neurocognitive function and clinical factors. STUDY TYPE: Prospective; longitudinal. POPULATION: In all, 34 patients and 30 healthy controls (HCs); the mean follow-up interval was 22 ± 7 months. FIELD STRENGTH/SEQUENCE: 3.0T, susceptibility-weighted imaging (SWI). ASSESSMENT: QSM reconstructed from original phase data of SWI was used to measure the susceptibility of gray matter structures including bilateral caudate nucleus (CN), globus pallidus (GP), putmen (PUT), red nucleus (RN), substantia nigra (SN), dentate nucleus (DN), thalamus (THA), pulvinar of thalamus (PT). The Mini-Mental State Examination (MMSE) test and clinical factors were recorded. STATISTICAL TESTING: Analysis of covariance adjusting for age and gender as covariates or a paired t-test for the differences in susceptibility, MMSE scores, and clinical factors among baseline, follow-up patients, and HCs. Correlation and stepwise regression analysis for the relationship between susceptibility, MMSE scores, and clinical factors. RESULTS: The susceptibility of bilateral CN, GP, PUT, RN, SN, DN, THA, PT in follow-up patients was significantly higher than that in baseline between patients and HCs except for left THA (all P < 0.05; Bonferroni corrected). MMSE scores significantly negatively correlated with the susceptibility of bilateral CN, PUT, and RRN in the baseline examination and bilateral CN, PUT, RN, and DN in the follow-up examination (all P < 0.05; false discovery rate [FDR] corrected). The follow-up interval, creatinine, phosphorus, and calcium were independent factors for the increased susceptibility of some nuclei (all P < 0.05). DATA CONCLUSION: The iron deposition of gray matter nuclei in hemodialysis patients increased over roughly a 2-year period and may be a risk factor for neurocognitive impairment. Creatinine and abnormal calcium-phosphorus metabolism were independent risk factors for abnormal iron deposition. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:786-799.

Native T1 mapping of autoimmune pancreatitis as a quantitative outcome surrogate.

OBJECTIVES: To investigate the ability of T1 mapping to visualize and quantify the short-term and mid-term response of autoimmune pancreatitis (AIP) to corticosteroid treatment (CST) and to correlate T1 relaxation time of the pancreas with clinical status and serum IgG4 level. METHODS: The institutional review board approved this prospective study, and all patients provided written informed consent. Pancreatic MRI including native T1 mapping was performed in 39 AIP patients before and during CST, and 40 patients without pancreatic diseases served as control. T1 relaxation time of the pancreatic head, body, and tail was measured in each patient. Clinical symptoms and serum IgG4 level of the patients were recorded. RESULTS: The native T1 relaxation time of AIP was significantly elongated compared to normal pancreatic tissue (1124.5 ms ± 95.7 ms vs 784.3 ms ± 41.8 ms, p < 0.001). After short-term CST (4 weeks), T1 relaxation time of AIP already shortened significantly (957.2 ms ± 97.3 ms, p < 0.001). After mid-term CST (12 weeks), the T1 relaxation time further shortened towards normalization (844.2 ms ± 71.6 ms, p < 0.001). In 33 AIP patients with elevated serum IgG4 at baseline, T1 relaxation time demonstrated a significant positive correlation with serum IgG4 level (r = 0.329, p = 0.011). In six AIP patients with normal serum IgG4 level at baseline, T1 relaxation time shortening preceded or was in accordance with symptom relief. CONCLUSIONS: Native T1 mapping can be used to assess parenchymal inflammation of AIP and to quantify response to treatment. It provides a quantitative outcome surrogate for AIP. KEY POINTS: • Parenchymal inflammation in autoimmune pancreatitis results in T1 relaxation time elongation, which shortens after effective treatment. • T1 relaxation time of the pancreas correlates with serum IgG4 level, and in serum IgG4-negative AIP patients, T1 relaxation time shortening predicts clinical improvement. • T1 mapping provides a quantitative outcome surrogate for AIP.

EEG/MEG source imaging using fMRI informed time-variant constraints.

Multimodal functional neuroimaging by combining functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) or magnetoencephalography (MEG) is able to provide high spatiotemporal resolution mapping of brain activity. However, the accuracy of fMRI-constrained EEG/MEG source imaging may be degraded by potential spatial mismatches between the locations of fMRI activation and electrical source activities. To address this problem, we propose a novel fMRI informed time-variant constraint (FITC) method. The weights in FITC are determined by combining the fMRI activities and electrical source activities in a time-variant manner to reduce the impact of the fMRI extra sources. The fMRI weights are modified using cross-talk matrix and normalized partial area under the curve to reduce the impact of fMRI missing sources. Monte Carlo simulations were performed to compare the source estimates produced by L2-minimum norm estimation (MNE), fMRI-weighted minimum norm estimation (fMNE), FITC, and depth-weighted FITC (wFITC) algorithms with various spatial mismatch conditions. Localization error and temporal correlation were calculated to compare the four algorithms under different conditions. The simulation results indicated that the FITC and wFITC methods were more robust than the MNE and fMNE algorithms. Moreover, FITC and wFITC were significantly better than fMNE under the fMRI missing sources condition. A human visual-stimulus EEG, MEG, and fMRI test was performed, and the experimental data revealed that FITC and wFITC displayed more focal areas than fMNE and MNE. In conclusion, the proposed FITC method is able to better resolve the spatial mismatch problems encountered in fMRI-constrained EEG/MEG source imaging.

Modified breath-hold compressed-sensing 3D MR cholangiopancreatography with a small field-of-view and high resolution acquisition: Clinical feasibility in biliary and pancreatic disorders.

BACKGROUND: Compressed-sensing (CS) accelerated 3D MR cholangiopancreatography (MRCP) could be acquired in both navigator-triggered (NT) and breath-hold (BH) mode, but the latter has been considered inferior in depicting pancreatic duct and diagnosing pancreatic duct-related diseases. PURPOSE: To prospectively evaluate the clinical feasibility of a modified 3D BH-CS-MRCP prototype protocol with small field-of-view (FOV) and higher spatial resolution, and to compare its performance to the original BH-CS-MRCP and NT-CS-MRCP. STUDY TYPE: Prospective cohort study. POPULATION: Eighty-two patients with suspected pancreaticobiliary diseases (46 male, median age, 55 years, range, 16-79 years), including seven noncooperative patients. FIELD STRENGTH/SEQUENCE: 3T, CS-MRCP. ASSESSMENT: Three protocols were performed in random order in each patient. Acquisition time of each protocol was recorded. Image quality, background suppression, duct visibility, and diagnostic confidence with duct anatomic variations and duct-related pathologies were rated on a 5-point scale by two blinded radiologists independently. STATISTICAL TESTS: The Wilcoxon signed-rank test was used to compare the intraindividual difference. Interobserver agreement was determined using kappa coefficients. The diagnostic performance was calculated using receiver operating characteristic curves. RESULTS: Acquisition time was 17 seconds for both BH-CS-MRCP protocols, and 127.5 ± 36.9 seconds for NT-CS-MRCP. In 75 cooperative patients, the incidence of major artifacts was low for all protocols (5.3-8.0%). Background suppression was similar with the two BH-CS-MRCP protocols (3.67 ± 0.77 for original BH-CS-MRCP and 3.70 ± 0. 57 for modified BH-CS-MRCP, respectively), both inferior to the NT-CS-MRCP protocol (4.41 ± 0.68, P < 0.001 for both). Modified BH-CS-MRCP and NT-CS-MRCP depicted pancreatic duct and second-level branches of biliary duct better than original BH-CS-MRCP (all P < 0.01). The diagnostic performance for detecting bile duct abnormalities was similar for all protocols (P = 0.53-0.87), whereas for detecting pancreatic duct abnormalities, modified BH-CS-MRCP and NT-CS-MRCP had significantly better performance compared to original BH-CS-MRCP (both P < 0.01). In seven noncooperative patients, NT-CS-MRCP had superior image quality than both BH protocols (both P < 0.01). DATA CONCLUSION: Modified BH-CS-MRCP is feasible for pancreatic and biliary disorders. NT-CS-MRCP might be more useful in noncooperative patients. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1389-1399.

Invasive placenta previa: Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta.

OBJECTIVES: To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). METHODS: Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. RESULTS: Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. CONCLUSION: Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. KEY POINTS: • Placental bulge type-II demonstrated the strongest independent association with PP. • Uterine serosal hypervascularity is a useful feature for differentiating PP from PA. • MRI features associated with abnormal vessels increase the risk of massive haemorrhage.

Improved Gray Matter Atrophy Detection in Alzheimer Disease in Chinese Populations Using Chinese Brain Template.

OBJECTIVE: This study aimed to test the hypothesis that the statistical Chinese brain template would be more effective to detect gray matter (GM) changes in patients with Alzheimer disease (AD) in Chinese populations. MATERIALS AND METHODS: In total, 50 patients with AD and 50 sex-matched and age-matched healthy controls were included in this study. Chinese2020, a typical statistical Chinese brain template, and MNI152, a typical Caucasian template were used for spatial normalization respectively. The GM volume alterations in patients with AD were examined by using voxel-based morphometry with education level and total intracranial volume as nuisance variables. The GM proportions of the identified brain areas with group difference were compared. RESULTS: By using Chinese2020 and MNI152, significant GM atrophies in patients with AD were commonly detected in the bilateral medial temporal lobe, lateral temporal lobe, inferior/medial frontal cortex, as well as left thalamus. However, higher GM percentages of detected regions were acquired when Chinese2020 was used rather than MNI152. Furthermore, stronger statistical powers in the detected clusters were observed using Chinese2020 than MNI152. In addition, the laterality index analysis showed the bilateral atrophies with no hemispheric laterality in the para/hippocampus when using population-specific brain atlas (ie, Chinese2020). CONCLUSIONS: These findings indicated that applying the population-specific brain atlas to neuroimaging studies may achieve higher accuracy in activation detection. This may have implications to the imaging study of neurodegenerative diseases.

Electroclinical characteristics of seizures arising from the precuneus based on stereoelectroencephalography (SEEG).

BACKGROUND: Seizures arising from the precuneus are rare, and few studies have aimed at characterizing the clinical presentation of such seizures within the anatomic context of the frontoparietal circuits. We aimed to characterize the electrophysiological properties and clinical features of seizures arising from the precuneus based on data from stereoelectroencephalography (SEEG). METHODS: The present retrospective study included 10 patients with medically intractable epilepsy, all of whom were diagnosed with precuneal epilepsy via stereoelectroencephalography (SEEG) at Yuquan Hospital and Xuan Wu Hospital between 2014 and 2016. Clinical semiology, scalp electroencephalography (EEG) findings, magnetic resonance images (MRI), and positron emission tomography (PET) images were analyzed during phase I preoperative evaluations. Following electrode implantation, the semiological sequence, ictal SEEG evolution, and anatomy of the relevant brain structures were analyzed for each seizure. RESULTS: Seven of ten patients reported auras, including body image disturbance (2/7), vestibular responses (2/7), somatosensory auras (1/7), visual auras (1/7), and non-specific auras (1/7). Primary motor manifestations included bilateral asymmetric tonic seizures (BATS) (7/10) and hypermotor seizures (HMS) (3/10). In one patient, epileptiform discharge on interictal EEG occurred ipsilateral to the side of the epileptogenic zone (EZ). Discharge was non-lateralized in the remaining nine patients. In six patients, interictal EEG signals were primarily localized in the temporal-parietal-occipital area. In two patients, ictal onset occurred ipsilateral to the EZ, which was mainly located in the temporal-parietal-occipital area. Two patterns of seizure spread were observed. The first pattern was characterized by BATS activity with ictal spread to the supplementary motor area (SMA), paracentral lobule (PCL), precentral gyrus (PrCG), or postcentral gyrus (PoCG). The second pattern was characterized by HMS activity with ictal spread to middle cingulate cortex (MCC) and posterior cingulate cortex (PCC). CONCLUSION: Aura type (e.g., body image disturbance and vestibular response), BATS, and HMS are the main indicators of precuneal epilepsy. Scalp EEG is of little use when attempting to localize precuneal seizures. Our findings indicate that the clinical characteristics of precuneal epilepsy vary among patients, and that the final electro-clinical phenotype depends on the pattern of seizure spread.

Reduced deep regional cerebral venous oxygen saturation in hemodialysis patients using quantitative susceptibility mapping.

Cerebral venous oxygen saturation (SvO2) is an important indicator of brain function. There was debate about lower cerebral oxygen metabolism in hemodialysis patients and there were no reports about the changes of deep regional cerebral SvO2 in hemodialysis patients. In this study, we aim to explore the deep regional cerebral SvO2 from straight sinus using quantitative susceptibility mapping (QSM) and the correlation with clinical risk factors and neuropsychiatric testing. 52 hemodialysis patients and 54 age-and gender-matched healthy controls were enrolled. QSM reconstructed from original phase data of 3.0 T susceptibility-weighted imaging was used to measure the susceptibility of straight sinus. The susceptibility was used to calculate the deep regional cerebral SvO2 and compare with healthy individuals. Correlation analysis was performed to investigate the correlation between deep regional cerebral SvO2, clinical risk factors and neuropsychiatric testing. The deep regional cerebral SvO2 of hemodialysis patients (72.5 ± 3.7%) was significantly lower than healthy controls (76.0 ± 2.1%) (P < 0.001). There was no significant difference in the measured volume of interests of straight sinus between hemodialysis patients (250.92 ± 46.65) and healthy controls (249.68 ± 49.68) (P = 0.859). There were no significant correlations between the measured susceptibility and volume of interests in hemodialysis patients (P = 0.204) and healthy controls (P = 0.562), respectively. Hematocrit (r = 0.480, P < 0.001, FDR corrected), hemoglobin (r = 0.440, P < 0.001, FDR corrected), red blood cell (r = 0.446, P = 0.003, FDR corrected), dialysis duration (r = 0.505, P = 0.002, FDR corrected) and parathyroid hormone (r = -0.451, P = 0.007, FDR corrected) were risk factors for decreased deep regional cerebral SvO2 in patients. The Mini-Mental State Examination (MMSE) scores of hemodialysis patients were significantly lower than healthy controls (P < 0.001). However, the deep regional cerebral SvO2 did not correlate with MMSE scores (P = 0.630). In summary, the decreased deep regional cerebral SvO2 occurred in hemodialysis patients and dialysis duration, parathyroid hormone, hematocrit, hemoglobin and red blood cell may be clinical risk factors.

BOLD-fMRI with median nerve electrical stimulation predict hemodynamic improvement after revascularization in patients with moyamoya disease.

PURPOSE: To assess the severity of cerebral hemodynamic impairment and hemodynamic improvements, after revascularization in moyamoya disease (MMD) by means of blood-oxygen-level dependent functional magnetic resonance imaging (BOLD-fMRI). MATERIALS AND METHODS: BOLD-fMRI with median nerve electrical stimulation based on echo planar imaging was performed in 73 volunteers with MMD and 15 healthy volunteers using a 3.0 Tesla MRI scanner. Twenty-four MMD patients were reexamined after encephaloduroarteriosynangiosis. Time-signal intensity curves of the activated area of the contralateral primary somatosensory cortex were computed. Negative response time (Tnr) and peak (Pnr), positive response time (Tpr) and peak (Ppr), and time to negative peak (TTPn) and positive peak (TTPp) were measured. RESULTS: Compared with nonparesthesia group and the asymptomatic side of paresthesia group, the patients with paresthesia showed extended Tnr (22.04 ± 3.34 s versus 9.57 ± 2.27 s and 12.67 ± 2.69 s, P = 0.0096), decreased Pnr (-0.47 ± 0.06 versus -0.30 ± 0.09 and -0.33 ± 0.09, P = 0.010), delayed TTPn (9.04 ± 1.39 s versus 3.66 ± 0.79 s and 4.88 ± 1.10 s, P = 0.0064), shortened Tpr (22.75 ± 2.30 s versus 36.85 ± 2.68 s and 33 ± 2.49 s, P = 0.0010), and decreased Ppr (0.62 ± 0.08 versus 0.99 ± 0.15 and 0.97 ± 0.11, P = 0.0149) when subjected to median nerve electrical stimulation in the symptomatic side. After surgery, the patients with paresthesia showed shorter Tnr (1.53 ± 1.66 s versus 17.88 ± 22.61 s, P = 0.0002), increased Pnr (-0.14 ± 0.17 versus -0.44 ± 0.53, P = 0.0178), advanced TTPn (1.29 ± 1.21 s versus 7.29 ± 8.21 s, P = 0.0005), extended Tpr (36.94 ± 6.41 s versus 25.18 ± 15.51 s, P = 0.0091), increased Ppr (1.21 ± 0.87 versus 0.77 ± 0.60, P = 0.0201), and advanced TTPp (11.18 ± 4.70 s versus 27.29 ± 20.00 s, P = 0.0046). CONCLUSION: Bold-fMRI is useful to assess disease severity and surgical efficacy in MMD. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2017;46:1159-1166.