T1 mapping as a quantitative imaging biomarker for diagnosing cervical cancer: a comparison with diffusion kurtosis imaging.

BACKGROUND: T1 mapping can potentially quantitatively assess the intrinsic properties of tumors. This study was conducted to explore the ability of T1 mapping in distinguishing cervical cancer type, grade, and stage and compare the diagnostic performance of T1 mapping with diffusion kurtosis imaging (DKI). METHODS: One hundred fifty-seven patients with pathologically confirmed cervical cancer were enrolled in this prospectively study. T1 mapping and DKI were performed. The native T1, difference between native and postcontrast T1 (T1diff), mean kurtosis (MK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) were calculated. Cervical squamous cell carcinoma (CSCC) and adenocarcinoma (CAC), low- and high-grade carcinomas, and early- and advanced-stage groups were compared using area under the receiver operating characteristic (AUROC) curves. RESULTS: The native T1 and MK were higher, and the MD and ADC were lower for CSCC than for CAC (all p < 0.05). Compared with low-grade CSCC, high-grade CSCC had decreased T1diff, MD, ADC, and increased MK (p < 0.05). Compared with low-grade CAC, high-grade CAC had decreased T1diff and increased MK (p < 0.05). Native T1 was significantly higher in the advanced-stage group than in the early-stage group (p < 0.05). The AUROC curves of native T1, MK, ADC and MD were 0,772, 0.731, 0.715, and 0.627, respectively, for distinguishing CSCC from CAC. The AUROC values were 0.762 between high- and low-grade CSCC and 0.835 between high- and low-grade CAC, with T1diff and MK showing the best discriminative values, respectively. For distinguishing between advanced-stage and early-stage cervical cancer, only the AUROC of native T1 was statistically significant (AUROC = 0.651, p = 0.002). CONCLUSIONS: Compared with DKI-derived parameters, native T1 exhibits better efficacy for identifying cervical cancer subtype and stage, and T1diff exhibits comparable discriminative value for cervical cancer grade.

A multicenter study of cervical cancer using quantitative diffusion-weighted imaging.

BACKGROUND: Parameters from diffusion-weighted imaging (DWI) have been increasingly used as imaging biomarkers for the diagnosis and monitoring of treatment responses in cancer. The consistency of DWI measurements across different centers remains uncertain, which limits the widespread use of quantitative DWI in clinical settings. PURPOSE: To investigate the consistency of quantitative metrics derived from DWI between different scanners in a multicenter clinical setting. MATERIAL AND METHODS: A total of 193 patients with cervical cancer from four scanners (MRI1, MRI2, MRI3, and MRI4) at three centers were included in this retrospective study. DWI data were processed using the mono-exponential and intravoxel incoherent motion (IVIM) model, yielding the following parameters: apparent diffusion coefficient (ADC); true diffusion coefficient (D); pseudo-diffusion coefficient (D*); perfusion fraction (f); and the product of f and D* (fD*). Various parameters of cervical cancer obtained from different scanners were compared. RESULTS: The parameters D and ADC derived from MRI1 and MRI2 were significantly different from those derived from MRI3 or MRI4 (P <0.01 for all comparisons). However, there was no significant difference in cervical cancer perfusion parameters (D* and fD*) between the different scanners (P >0.05). The P values of comparisons of all DWI parameters (D, D*, fD*, and ADC) between MRI3 and MRI4 (same vendor in different centers) for cervical cancer were all >0.05, except for f (P = 0.05). CONCLUSION: Scanners of the same model by the same vendor can yield close measurements of the ADC and IVIM parameters. The perfusion parameters showed higher consistency among the different scanners.

Added-value of 3D amide proton transfer MRI in assessing prognostic factors of cervical cancer: a comparative study with multiple model diffusion-weighted imaging.

Background: Amide proton transfer (APT) imaging has been gradually applied to cervical cancer, yet the relationships between APT and multiple model diffusion-weighted imaging (DWI) have yet to be investigated. This study attempted to evaluate the added value of 3-dimensional (3D) APT imaging to multiple model DWI for assessing prognostic factors of cervical cancer. Methods: This prospective diagnostic study was conducted in The First Affiliated Hospital of Zhengzhou University. A total of 88 consecutive patients with cervical cancer underwent APT imaging and DWI with 11 b-values (0-2,000 s/mm2). The apparent diffusion coefficient (ADC), pure molecular diffusion (D), perfusion fraction (f), pseudo-diffusion (D*), mean kurtosis (MK), and mean diffusivity (MD) were calculated based on mono-exponential, bi-exponential, and kurtosis models. The mean, minimum, and maximum values of APT signal intensity (APT SI) and DWI-derived metrics were compared based on tumor stages, subtypes, grades, and lymphovascular space invasion status by Student's t-test or Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic performance of the parameters. Results: APT SImax, APT SImin, MKmean, and MKmax showed significant differences between adenocarcinoma (AC) and squamous cell carcinoma (SCC) (all P<0.05). APT SImean, APT SImax, and MKmax were higher and ADCmin, Dmean, Dmin, and MDmin were lower in the high-grade tumor than in low-grade tumor (all P<0.05). For distinguishing lymphovascular space invasion, only MKmean showed significant difference (P=0.010). APT SImax [odds ratio (OR) =2.347, P=0.029], APT SImin (OR =0.352; P=0.024), and MKmean (OR =6.523; P=0.001) were the independent predictors for tumor subtype, and APT SImax (OR =2.885; P=0.044), MDmin (OR =0.155, P=0.012) were the independent predictors for histological grade of cervical cancer. When APT SImin and APT SImax was combined with MKmean and MKmax, the diagnostic performance was significantly improved for differentiating AC and AC [area under the curve (AUC): 0.908, sensitivity: 87.5%; specificity: 83.3%; P<0.001]. The combination of APT SImean, APT SImax, ADCmin, MKmax, and MDmin demonstrated the highest diagnostic performance for predicting tumor grade (AUC: 0.903, sensitivity: 78.6%; specificity: 88.9%; P<0.001). Conclusions: Addition of APT to DWI may improve the ability to noninvasively predict poor prognostic factors of cervical cancer.

Feasibility of accelerated T2 mapping for the preoperative assessment of endometrial carcinoma.

Objective: The application value of T2 mapping in evaluating endometrial carcinoma (EMC) features remains unclear. The aim of the study was to determine the quantitative T2 values in EMC using a novel accelerated T2 mapping, and evaluate them for detection, classification,and grading of EMC. Materials and methods: Fifty-six patients with pathologically confirmed EMC and 17 healthy volunteers were prospectively enrolled in this study. All participants underwent pelvic magnetic resonance imaging, including DWI and accelerated T2 mapping, before treatment. The T2 and apparent diffusion coefficient (ADC) values of different pathologic EMC features were extracted and compared. Receiver operating characteristic (ROC) curve analysis was performed to analyze the diagnostic efficacy of the T2 and ADC values in distinguishing different pathological features of EMC. Results: The T2 values and ADC values were significantly lower in EMC than in normal endometrium (bothl p < 0.05). The T2 and ADC values were significantly different between endometrioid adenocarcinoma (EA) and non-EA (both p < 0.05) and EMC tumor grades (all p < 0.05) but not for EMC clinical types (both p > 0.05) and depth of myometrial invasion (both p > 0.05). The area under the ROC curve (AUC) was higher for T2 values than for ADC values in predicting grade 3 EA (0.939 vs. 0.764, p = 0.048). When combined T2 and ADC values, the AUC for predicting grade 3 EA showed a significant increase to 0.947 (p = 0.03) compared with those of ADC values. The T2 and ADC values were negatively correlated with the tumor grades (r = -0.706 and r = -0.537, respectively). Conclusion: Quantitative T2 values demonstrate potential suitability in discriminating between EMC and normal endometrium, EA and non-EA, grade 3 EA and grade 1/2 EA. Combining T2 and ADC values performs better in predicting the histological grades of EA in comparison with ADC values alone.

Connectome-based predictive modeling of smoking severity using individualized structural covariance network in smokers.

Introduction: Abnormal interactions among distributed brain systems are implicated in the mechanisms of nicotine addiction. However, the relationship between the structural covariance network, a measure of brain connectivity, and smoking severity remains unclear. To fill this gap, this study aimed to investigate the relationship between structural covariance network and smoking severity in smokers. Methods: A total of 101 male smokers and 51 male non-smokers were recruited, and they underwent a T1-weighted anatomical image scan. First, an individualized structural covariance network was derived via a jackknife-bias estimation procedure for each participant. Then, a data-driven machine learning method called connectome-based predictive modeling (CPM) was conducted to infer smoking severity measured with Fagerström Test for Nicotine Dependence (FTND) scores using an individualized structural covariance network. The performance of CPM was evaluated using the leave-one-out cross-validation and a permutation testing. Results: As a result, CPM identified the smoking severity-related structural covariance network, as indicated by a significant correlation between predicted and actual FTND scores (r = 0.23, permutation p = 0.020). Identified networks comprised of edges mainly located between the subcortical-cerebellum network and networks including the frontoparietal default model and motor and visual networks. Discussion: These results identified smoking severity-related structural covariance networks and provided a new insight into the neural underpinnings of smoking severity.

Synthetic MRI for the quantitative and morphologic assessment of head and neck tumors: a preliminary study.

OBJECTIVES: To evaluate the feasibility of synthetic MRI for quantitative and morphologic assessment of head and neck tumors and compare the results with the conventional MRI approach. METHODS AND MATERIALS: A total of 92 patients with different head and neck tumor histology who underwent conventional and synthetic MRI were retrospectively recruited. The quantitative T1, T2, proton density (PD), and apparent diffusion coefficient (ADC) values of 38 benign and 54 malignant tumors were measured and compared. Diagnostic efficacy for differentiating malignant and benign tumors was evaluated with receiver operating characteristic (ROC) analysis and integrated discrimination index. The image quality of conventional and synthetic T1W/T2W images on a 5-level Likert scale was also compared with Wilcoxon signed rank test. RESULTS: T1, T2 and ADC values of malignant head and neck tumors were smaller than those of benign tumors (all p < 0.05). T2 and ADC values showed better diagnostic efficacy than T1 for distinguishing malignant tumors from benign tumors (both p < 0.05). Adding the T2 value to ADC increased the area under the curve from 0.839 to 0.886, with an integrated discrimination index of 4.28% (p < 0.05). In terms of overall image quality, synthetic T2W images were comparable to conventional T2W images, while synthetic T1W images were inferior to conventional T1W images. CONCLUSIONS: Synthetic MRI can facilitate the characterization of head and neck tumors by providing quantitative relaxation parameters and synthetic T2W images. T2 values added to ADC values may further improve the differentiation of tumors.

Mechanism of groundwater recharge in the thick loess deposits by multiple environmental tracers.

The loess-covered region accounts for ∼10 % of global land surface. Because of dry climate and thick vadose zones, the subsurface water flux is low but the water storage is relatively large . As a result, the groundwater recharge mechanism is complicated and currently controversial (e.g., piston flow or dual mode with piston and preferential flow). Taking typical tablelands in China's Loess Plateau as example study area, this study aims to qualitatively and quantitively evaluate the forms/rates and controls of groundwater recharge considering space and time. We collected 498 precipitation, soil water and groundwater samples in 2014-2021 for hydrochemical and isotopic analysis (Cl-, NO3-, δ18O, δ2H, 3H and 14C). A graphical method was employed to determine appropriate model to correct 14C age. Dual model exhibited in the recharge: regional-scale piston flow and local-scale preferential flow. Piston flow dominated groundwater recharge with a proportion of 77 %-89 %. Preferential flow gradually declined with increasing water table depths, and the upper depth limit may be <40 m. The dynamics of tracers proved that mixing and dispersion effects of aquifers limited the ability of tracers to capture preferential flow at short-time scales. Long-term average potential recharge (79 ± 49 mm/year) was close to actual recharge (85 ± 41 mm/year) at the regional scale, indicating the hydraulic equilibrium between unsaturated and saturated zones. The thickness of vadose zone controlled recharge forms, and precipitation dominated the potential and actual recharge rates. Land-use change can also affect the potential recharge rates at point and field scales but maintain the dominance of piston flow. The revealed spatially-varied recharge mechanism is useful for groundwater modeling and the method can be referred for studying recharge mechanism in thick aquifers.

[Temporal and Spatial Distribution Characteristics and Source Analysis of Nitrate in Surface Water of Wuding River Basin].

The Wuding River Basin is a first-class tributary of the Yellow River, and the quality of its water ecological environment has a profound impact on the ecological protection and high-quality development of the Yellow River Basin. In order to identify the source of nitrate pollution in the Wuding River Basin, surface water samples of the Wuding River were collected from 2019 to 2021, and the temporal and spatial distribution characteristics and influencing factors of nitrate concentration in surface water in the basin were explored. Nitrogen and oxygen isotope tracer technology and the MixSIAR model were used to qualitatively and quantitatively determine the sources of surface water nitrate and their contribution rates. The results showed that there were significant spatial and temporal differences in nitrate concentrations in the Wuding River Basin. In terms of time, the mean concentration of NO-3-N in surface water in the wet season was higher than that in the flat-water period; spatially, the mean concentration of NO-3-N in the downstream surface water was higher than that in the upstream. The spatial and temporal differences in surface water nitrate concentrations were mainly affected by rainfall runoff, soil types, and land use types. The main sources of nitrates in the surface water of the Wuding River Basin during the wet season were domestic sewage, manure, chemical fertilizers, and soil organic nitrogen, whose contribution rates were 43.3%, 27.6%, and 22.1%, respectively, and the contribution rate of precipitation was only 7.0%. There were differences in the contribution rate of nitrate pollution sources in surface water of different river sections. The contribution rate of soil nitrogen in the upstream was significantly higher than that in the downstream, which was 26.5%. The contribution rate of domestic sewage and manure in the downstream was significantly higher than that in the upstream, which was 48.9%. To provide a basis for the analysis of nitrate sources and pollution control in Wuding River and even rivers in arid and semi-arid regions.

Prediction of Recurrent Cervical Cancer in 2-Year Follow-Up After Treatment Based on Quantitative and Qualitative Magnetic Resonance Imaging Parameters: A Preliminary Study.

PURPOSE: This study investigated predictors of cervical cancer (CC) recurrence from native T1 mapping, conventional imaging, and clinicopathologic metrics. PATIENTS AND METHODS: In total, 144 patients with histopathologically confirmed CC (90 with and 54 without surgical treatment) were enrolled in this prospective study. Native T1 relaxation time, conventional imaging, and clinicopathologic characteristics were acquired. The association of quantitative and qualitative parameters with post-treatment tumor recurrence was assessed using univariate and multivariate Cox proportional hazard regression analyses. Independent risk factors were combined into a model and individual prognostic index equation for predicting recurrence risk. The receiver operating characteristic (ROC) curve determined the optimal cutoff point. RESULTS: In total, 12 of 90 (13.3%) surgically treated patients experienced tumor recurrence. Native T1 values (X1) [hazard ratio (HR) 1.008; 95% confidence interval (CI) 1.001-1.016], maximum tumor diameter (X2) (HR 1.065; 95% CI 1.020-1.113), and parametrial invasion (X3) (HR 3.930; 95% CI 1.013-15.251) were independent tumor recurrence risk factors. The individual prognostic index (PI) of the established recurrence risk model was PI = 0.008X1 + 0.063X2 + 1.369X3. The area under the ROC curve (AUC) of the Cox regression model was 0.923. A total of 20 of 54 (37.0%) non-surgical patients experienced tumor recurrence. Native T1 values (X1) (HR 1.012; 95% CI 1.007-1.016) and lymph node metastasis (X2) (HR 4.064; 95% CI 1.378-11.990) were independent tumor recurrence risk factors. The corresponding PI was calculated as follows: PI = 0.011X1 + 1.402X2; the Cox regression model AUC was 0.921. CONCLUSIONS: Native T1 values combined with conventional imaging and clinicopathologic variables could facilitate the pretreatment prediction of CC recurrence.

Solid-State Electrolyte for Lithium-Air Batteries: A Review.

Traditional lithium-air batteries (LABs) have been seriously affected by cycle performance and safety issues due to many problems such as the volatility and leakage of liquid organic electrolyte, the generation of interface byproducts, and short circuits caused by the penetration of anode lithium dendrite, which has hindered its commercial application and development. In recent years, the emergence of solid-state electrolytes (SSEs) for LABs well alleviated the above problems. SSEs can prevent moisture, oxygen, and other contaminants from reaching the lithium metal anode, and their inherent performance can solve the generation of lithium dendrites, making them potential candidates for the development of high energy density and safety LABs. This paper mainly reviews the research progress of SSEs for LABs, the challenges and opportunities for synthesis and characterization, and future strategies are addressed.

T1 mapping and multimodel diffusion-weighted imaging in the assessment of cervical cancer: a preliminary study.

OBJECTIVE: To evaluate the clinical feasibility of T1 mapping and multimodel diffusion-weighted imaging (DWI) for assessing the histological type, grade, and lymphovascular space invasion (LVSI) of cervical cancer. METHODS: Eighty patients with cervical cancer and 43 patients with a normal cervix underwent T1 mapping and DWI with 11 b-values (0-2000 s/mm2). Monoexponential, biexponential, and kurtosis models were fitted to calculate the apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion (D*), perfusion fraction (f), mean diffusivity (MD), and mean kurtosis (MK). Native T1 and DWI-derived parameters (ADCmean, ADCmin, Dmean, Dmin, D*, f, MDmean, MDmin, MKmean, and MKmax) were compared based on histological type, grade, and LVSI status. RESULTS: Native T1 and DWI-derived parameters differed significantly between cervical cancer and normal cervix (all p < 0.05), except D* (p = 0.637). Native T1 and MKmean varied significantly between squamous cell carcinoma (SCC) and adenocarcinoma (both p < 0.05). ADCmin, Dmin, and MDmin were significantly lower while MKmax was significantly higher in the high-grade SCC group than in the low-grade SCC group (all p < 0.05). LVSI-positive SCC had a significantly higher MKmean than LVSI-negative SCC (p < 0.05). CONCLUSION: Both T1 mapping and multimodel DWI can effectively differentiate cervical cancer from a normal cervix and cervical adenocarcinoma from SCC. Furthermore, multimodel DWI may provide quantitative metrics for non-invasively predicting histological grade and LVSI status in SCC patients. ADVANCES IN KNOWLEDGE: Combined use of T1 mapping and multimodel DWI may provide more comprehensive information for non-invasive pre-operative evaluation of cervical cancer.

Risk factors for the recurrence of cervical cancer using MR-based T1 mapping: A pilot study.

Objectives: This study aimed to identify risk factors for recurrence in patients with cervical cancer (CC) through quantitative T1 mapping. Methods: A cohort of 107 patients histopathologically diagnosed with CC at our institution between May 2018 and April 2021 was categorized into surgical and non-surgical groups. Patients in each group were further divided into recurrence and non-recurrence subgroups depending on whether they showed recurrence or metastasis within 3 years of treatment. The longitudinal relaxation time (native T1) and apparent diffusion coefficient (ADC) value of the tumor were calculated. The differences between native T1 and ADC values of the recurrence and non-recurrence subgroups were analyzed, and receiver operating characteristic (ROC) curves were drawn for parameters with statistical differences. Logistic regression was performed for analysis of significant factors affecting CC recurrence. Recurrence-free survival rates were estimated by Kaplan-Meier analysis and compared using the log-rank test. Results: Thirteen and 10 patients in the surgical and non-surgical groups, respectively, showed recurrence after treatment. There were significant differences in native T1 values between the recurrence and non-recurrence subgroups in the surgical and non-surgical groups (P<0.05); however, there was no difference in ADC values (P>0.05). The areas under the ROC curve of native T1 values for discriminating recurrence of CC after surgical and non-surgical treatment were 0.742 and 0.780, respectively. Logistic regression analysis indicated that native T1 values were risk factors for tumor recurrence in the surgical and non-surgical groups (P=0.004 and 0.040, respectively). Compared with cut-offs, recurrence-free survival curves of patients with higher native T1 values of the two groups were significantly different from those with lower ones (P=0.000 and 0.016, respectively). Conclusion: Quantitative T1 mapping could help identify CC patients with a high risk of recurrence, supplementing information on tumor prognosis other than clinicopathological features and providing the basis for individualized treatment and follow-up schemes.

Complex cerebrovascular diseases in Roberts syndrome caused by novel biallelic ESCO2 variations.

OBJECTIVE: Roberts syndrome (RBS), also known as Roberts-SC phocomelia syndrome, is a rare autosomal recessive developmental disorder caused by mutations in the ESCO2 gene. Cardinal clinical manifestations are pre- and postnatal growth retardation and craniofacial and limb malformations. Here, we report RBS in a Chinese adolescent with novel biallelic ESCO2 variations and complex cerebrovascular diseases. METHODS: Medical history, neurological examinations, neuroimaging, and pathology were collected in the proband and the family. Whole exome sequencing (WES) with copy number variation analysis was performed to screen for genetic variations. RESULTS: The clinical features of the proband were craniofacial and limb malformations together with complex cerebrovascular diseases. She suffered ischemic stroke at 6 years old and died of cerebellar hemorrhage secondary to an aneurysm at 13 years old. Besides, neuroimaging showed the triad of leukoencephalopathy, calcifications, and cysts. Brain histopathology revealed angiomatous changes and perivascular cysts suggesting chronic small cerebral vasculopathy. Whole exome sequencing (WES) identified novel biallelic variations in the ESCO2 gene (c.1220A>T, p.H407L and c.1562delC, p.A521fs). CONCLUSIONS: We describe complex cerebrovascular diseases in Roberts syndrome caused by novel ESCO2 biallelic variations. This case expands not only the cerebral involvement in Roberts syndrome but also the disease spectrum of the neuroimaging triad with leukoencephalopathy, calcifications, and cysts.

[Clinical characteristics and genetic analysis of a case with adult neuronal ceroid lipofuscinosis type 7 due to variant of MFSD8 gene].

OBJECTIVE: To explore the clinical characteristics and genetic variants in a patient with adult ceroid lipofuscinosis neuronal type 7 (ACLN7). METHODS: A female patient diagnosed with ACLN7 in Henan Provincial People's Hospital in June 2021 was selected as the study subject. Clinical data, auxiliary examination and result of genetic testing were retrospectively analyzed. RESULTS: The patient, a 39-year-old female, has mainly presented progressive visual loss, epilepsy, cerebellar ataxia and mild cognitive decline. Neuroimaging analysis has revealed generalized brain atrophy, prominently cerebellum. Fundus photography has revealed retinitis pigmentosa. Ultrastructural skin examination has revealed granular lipofuscin deposits in the periglandular interstitial cells. Whole exome sequencing revealed that she has harbored compound heterozygous variants of the MSFD8 gene, namely c.1444C>T (p.R482*) and c.104G>A (p.R35Q). Among these, c.1444C>T (p.R482*) was a well established pathogenic variant, while c.104G>A (p.R35Q) was a missense variant unreported previously. Sanger sequencing confirmed that the daughter, son and elder brother of the proband have respectively carried heterozygous c.1444C>T (p.R482*), c.104G>A (p.R35Q), and c.104G>A (p.R35Q) variants of the same gene. The family has therefore fit with the autosomal recessive inheritance pattern of the CLN7. CONCLUSION: Compared with previously reported cases, this patient has the latest onset of the disease with a non-lethal phenotype. Her clinical features have involved multiple systems. Cerebellar atrophy and fundus photography may be indicative of the diagnosis. The c.1444C>T (p.R482*) and c.104G>A (p.R35Q) compound heterozygous variants of the MFSD8 gene probably underlay the pathogenesis in this patient.

T1 mapping and extracellular volume fraction measurement to evaluate the poor-prognosis factors in patients with cervical squamous cell carcinoma.

PURPOSE: To evaluate the clinical feasibility of T1 mapping and extracellular volume fraction (ECV) measurement in assessing prognostic factors in patients with cervical squamous cell carcinoma (CSCC). MATERIALS AND METHODS: A total of 117 CSCC patients and 59 healthy volunteers underwent T1 mapping and diffusion-weighted imaging (DWI) on a 3 T system. Native T1 , contrast-enhanced T1 , ECV, and apparent diffusion coefficient (ADC) were calculated and compared based on surgico-pathologically verified deep stromal infiltration, parametrial invasion (PMI), lymphovascular space invasion (LVSI), lymph node metastasis, stage, histologic grade, and the Ki-67 labeling index (LI). RESULTS: Native T1 , contrast-enhanced T1 , ECV, and ADC values were significantly different between CSCC and the normal cervix (all p < 0.05). No significant differences were observed in any parameters of CSCC when the tumors were grouped by stromal infiltration or lymph node status, respectively (all p > 0.05). In subgroups of the tumor stage and PMI, native T1 was significantly higher for advanced-stage (p = 0.032) and PMI-positive CSCC (p = 0.001). In subgroups of the grade and Ki-67 LI, contrast-enhanced T1 was significantly higher for high-grade (p = 0.012) and Ki-67 LI ≥ 50% tumors (p = 0.027). ECV was significantly higher in LVSI-positive CSCC than in LVSI-negative CSCC (p < 0.001). ADC values showed a significant difference for the grade (p < 0.001) but none for the other subgroups. CONCLUSION: Both T1 mapping and DWI could stratify the CSCC histologic grade. In addition, T1 mapping and ECV measurement might provide more quantitative metrics for noninvasively predicting poor prognostic factors and aiding in preoperative risk assessment in CSCC patients.

Evaluation of tracer kinetic parameters in cervical cancer using dynamic contrast-enhanced MRI as biomarkers in terms of biological relevance, diagnostic performance and inter-center variability.

Objectives: This study assessed the clinical value of parameters derived from dynamic contrast-enhanced (DCE) MRI with respect to correlation with angiogenesis and proliferation of cervical cancer, performance of diagnosis and reproducibility of DCE-MRI parameters across MRI scanners. Materials and Methods: A total of 113 patients with cervical carcinoma from two centers were included in this retrospective study. The DCE data were centralized and processed using five tracer kinetic models (TKMs) (Tofts, Ex-Tofts, ATH, SC, and DP), yielding the following parameters: volume transfer constant (Ktrans), extravascular extracellular volume (Ve), fractional volume of vascular space (Vp), blood flow (Fp), and permeability surface area product (PS). CD34 counts and Ki-67 PI (proliferation index) of cervical cancer and normal cervix tissue were obtained using immunohistochemical staining in Center 1. Results: CD34 count and Ki-67 PI in cervical cancer were significantly higher than in normal cervix tissue (p<0.05). Parameter Ve from each TKM was significantly smaller in cervical cancer tissue than in normal cervix tissue (p<0.05), indicating the higher proliferation of cervical cancer cells. Ve of each TKM attained the largest AUC to diagnose cervical cancer. The distributions of DCE parameters for both cervical cancer and normal cervix tissue were not significantly different between two centers (P>0.05). Conclusion: Parameter Ve was similar to the expression of Ki-67 in revealing the proliferation of tissue cells, attained good performance in diagnosis of cervical cancer, and demonstrated consistent findings on measured values across centers.

Impaired brain networks functional connectivity after acute mild hypoxia.

This study aimed to analyze the changes in brain networks functional connectivity of pilots exposed to simulated hypoxia using resting-state functional magnetic resonance imaging (fMRI). A total of 35 healthy male pilots exposed to 14.5% oxygen concentration (corresponding to an altitude of 3000 m) underwent resting-state fMRI scans. The independent component analysis (ICA) approach was used to analyze changes in the resting-state brain networks functional connectivity of pilots after hypoxic exposure, and 9 common components in brain functional networks were identified. In the functional connections that showed significant group differences, linear regression was used to examine the association between functional connectivity and clinical characteristics. The brain networks functional connectivity after hypoxia exposure decreased significantly, including the left frontoparietal network and visual network 1-area, left frontoparietal network and visual network 2-area, right frontoparietal network and visual network 2-area, dorsal attention network and ventral attention network, dorsal attention network and auditory network, and ventral attention network and visual network 1-area. We found no correlation between the altered functional connectivity and arterial oxygen saturation level. Our findings provide insights into the mechanisms underlying hypoxia-induced cognitive impairment in pilots.

Failure and deformation characteristics of shale subject to true triaxial stress loading and unloading under water retention and seepage.

A multi-functional true triaxial fluid-structure coupling system was used to conduct water retention and seepage tests of shale under true triaxial loading and unloading stress paths. The stress-strain evolution of shale specimens under different experimental conditions was obtained, and the corresponding deformation and strength were analysed. The evolution and failure characteristics of cracks in shale were obtained by CT scanning images before and after the experiment. The results show that the volumetric strain of shale specimen increases first, then decreases and finally continues to increase with an increase in deviatoric stress under water retention, indicating that the volumetric change has experienced a compaction-expansion-compacting. The σ-ε 1 curve of the sample increases first and then decreases, while the deformation in the σ 2 direction shows the repeated compression and expansion. In the seepage test, the permeability-strain curve can be divided into two parts before and after fracture according to the σ-ε 1 curve. Before fracture, the compression velocity of the specimen in the loading direction exceeds the expansion velocity in the unloading direction, resulting in a decrease in volume and a decrease in permeability. With an increase in deviatoric stress, fractures occur inside the particles and continue to spread from the tip until the fractures break through the shale specimen. The pore fissure area increases and the permeability of the sample increases rapidly. In terms of fracture evolution, for the water retention test, dense tensile and shear cracks appear on the failure plane perpendicular to the σ 1 and σ 3 directions, and complex shear fracture network appears on the failure plane perpendicular to the σ 2 direction. For the seepage test, heavy shear failure occurs throughout the original fracture of the sample. With an increase in the penetration depth, the fracture shape on the failure surface perpendicular to the σ 2 direction gradually changes from single to complex.