Pseudomonas-associated bacteria play a key role in obtaining nutrition from bamboo for the giant panda (Ailuropoda melanoleuca).

Gut microbiota plays a vital role in obtaining nutrition from bamboo for giant pandas. However, low cellulase activity has been observed in the panda's gut. Besides, no specific pathway has been implicated in lignin digestion by gut microbiota of pandas. Therefore, the mechanism by which they obtain nutrients is still controversial. It is necessary to elucidate the precise pathways employed by gut microbiota of pandas to degrade lignin. Here, the metabolic pathways for lignin degradation in pandas were explored by comparing 209 metagenomic sequencing data from wild species with different feeding habits. Lignin degradation central pathways, including beta-ketoadipate and homogentisate pathway, were enriched in the gut of wild bamboo-eating pandas. The gut microbiome of wild bamboo-eating specialists was enriched with genes from pathways implicated in degrading ferulate and p-coumarate into acetyl-CoA and succinyl-CoA, which can potentially provide the raw materials for metabolism in pandas. Specifically, Pseudomonas, as the most dominant gut bacteria genus, was found to be the main bacteria to provide genes involved in lignin or lignin derivative degradation. Herein, three Pseudomonas-associated strains isolated from the feces of wild pandas showed the laccase, lignin peroxidase, and manganese peroxidase activity and extracellular lignin degradation ability in vitro. A potential mechanism for pandas to obtain nutrition from bamboo was proposed based on the results. This study provides novel insights into the adaptive evolution of pandas from the perspective of lignin metabolism. IMPORTANCE: Although giant pandas only feed on bamboo, the mechanism of lignin digestion in pandas is unclear. Here, the metabolic pathways for lignin degradation in wild pandas were explored by comparing gut metagenomic from species with different feeding habits. Results showed that lignin degradation central pathways, including beta-ketoadipate and homogentisate pathway, were enriched in the gut of wild bamboo-eating pandas. Genes from pathways involved in degrading ferulate and p-coumarate via beta-ketoadipate pathway were also enriched in bamboo-eating pandas. The final products of the above process, such as acetyl-CoA, can potentially provide the raw materials for metabolism in pandas. Specifically, Pseudomonas, as the most dominant gut bacteria genus, mainly provides genes involved in lignin degradation. Herein, Pseudomonas-associated strains isolated from the feces of pandas could degrade extracellular lignin. These findings suggest that gut microbiome of pandas is crucial in obtaining nutrition from lignin via Pseudomonas, as the main lignin-degrading bacteria.

Deep-Learning-Enabled High-Fidelity Absorbance Spectra from Distorted Dual-Comb Absorption Spectroscopy for Gas Quantification Analysis.

Dual-comb absorption spectroscopy has been a promising technique in laser spectroscopy due to its intrinsic advantages over broad spectral coverage, high resolution, high acquisition speed, and frequency accuracy. However, two primary challenges, including etalon effects and complex baseline extraction, still severely hinder its implementation in recovering absorbance spectra and subsequent quantification analysis. In this paper, we propose a deep learning enabled processing framework containing etalon removal and baseline extraction modules to obtain absorbance spectra from distorted dual-comb absorption spectroscopy. The etalon removal module utilizes a typical U-net model, and the baseline extraction module consists of a modified U-net model with physical constraint and an adaptive iteratively reweighted penalized least squares method serving as refinement. The training datasets combine experimental baselines and simulated gas absorption with different concentrations, fully exploiting prior information on gas absorption features from the HITRAN database. In the simulated and experimental test, the CO2 absorbance spectrum covering 25 cm-1 shows high consistency with the HITRAN database, of which the mean absolute error is less than 1% of the maximum absorbance value, and the retrieved concentration has a relative error under 2%, outperforming traditional approaches and indicating the potential practicality of our data processing framework. Hopefully, with a larger network volume and proper datasets, this processing framework can be extended to precise quantification analysis in more comprehensive applications such as atmospheric measurement and industrial monitoring.

The impact of platelet indices on ischemic stroke: a Mendelian randomization study and mediation analysis.

Introduction: Platelet indices (PIs) are hematological parameters that indicate the number, morphology, and activation of platelets. Although some clinical trials suggest an association between PIs and the risk of stroke, the lack of robust evidence is attributed to confounding effects and reverse causation. Objective: This study aimed to evaluate the association between PIs and stroke risk through Mendelian randomization (MR) while exploring the mediating effect of blood pressure in this association. Methods: We identified genetic variants associated with PIs, including platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), and platelet crit (PCT), in the UK Biobank (n = 350,474). Relevant genome-wide association studies were utilized to gather summary statistics pertaining to the traits of interest. We primarily used the inverse-variance weighted analysis to obtain estimates for individual causal power. Result: We observed a positive correlation between genetically predicted increases in PCT levels with the stroke onset [PCT: OR (95%CI) = 1.113(1.047, 1.183), p < 0.001]. However, no significant causal relationship was found between PLT, PDW, and MPV and the risk of stroke [PLT: OR (95%CI) = 1.037(0.979, 1.098), p = 0.221; PDW: OR (95%CI) = 0.973(0.923, 1.024), p = 0.294; MPV: OR (95%CI) = 0.990(0.945, 1.038), p = 0.675]. Multivariable MR analyses and mediation analysis found that the proportion mediated by systolic blood pressure (SBP) is 23.71% [95%CI (10.85-33.31%)] and the proportion mediated by diastolic blood pressure (DBP) is 28.09% [95%CI (12.92-39.63%)]. Conclusion: This large MR study presents evidence for the potential causal relationship between the PCT level and the risk of ischemic stroke, which might be mediated by blood pressure.

Characterization and Comparative Genomic Analysis of a Deep-Sea Bacillus Phage Reveal a Novel Genus.

As the most abundant biological entities, viruses are the major players in marine ecosystems. However, our knowledge on virus diversity and virus-host interactions in the deep sea remains very limited. In this study, vB_BteM-A9Y, a novel bacteriophage infecting Bacillus tequilensis, was isolated from deep-sea sediments in the South China Sea. vB_BteM-A9Y has a hexametric head and a long, complex contractile tail, which are typical features of myophages. vB_BteM-A9Y initiated host lysis at 60 min post infection with a burst size of 75 PFU/cell. The phage genome comprises 38,634 base pairs and encodes 54 predicted open reading frames (ORFs), of which 27 ORFs can be functionally annotated by homology analysis. Interestingly, abundant ORFs involved in DNA damage repair were identified in the phage genome, suggesting that vB_BteM-A9Y encodes multiple pathways for DNA damage repair, which may help to maintain the stability of the host/phage genome. A BLASTn search of the whole genome sequence of vB_BteM-A9Y against the GenBank revealed no existing homolog. Consistently, a phylogenomic tree and proteome-based phylogenetic tree analysis showed that vB_BteM-A9Y formed a unique branch. Further comparative analysis of genomic nucleotide similarity and ORF homology of vB_BteM-A9Y with its mostly related phages showed that the intergenomic similarity between vB_BteM-A9Y and these phages was 0-33.2%. Collectively, based on the comprehensive morphological, phylogenetic, and comparative genomic analysis, we propose that vB_BteM-A9Y belongs to a novel genus under Caudoviricetes. Therefore, our study will increase our knowledge on deep-sea virus diversity and virus-host interactions, as well as expanding our knowledge on phage taxonomy.

Detection of the gene mutation of epidermal growth factor receptor in lung adenocarcinoma by radiomic features from a small amount of PET data.

OBJECTIVE: The purpose of this work was to identify the potential mutation of epidermal growth factor receptor in nonsmall cell adenocarcinoma by noninvasive method, and to explore whether the same or better effect can be achieved using a small amount of single-mode PET image data. METHOD: A total of 115 patients were recruited and the results of their 18F-FDG PET images and gene detection after resection were obtained; 117 original radiation features and 744 wavelet transform features were extracted from PET images. Several methods were used to reduce the dimension of the data, and four classifier models were established to classify it. The above process was repeated to reduce the total amount of data and the area under the receiver operating characteristic curve (AUC) value that changed with the reduction of the data and the stability of the results was recorded. RESULTS: The classifier with the best comprehensive performance under this dataset was logistic regression, whose AUC value is 0.843. And similar results can be obtained from only 30 cases of data. CONCLUSION: A similar or better result could be achieved using a small number of single-mode PET images. In addition, significant results could be obtained using only the PET images of 30 patients.

Diagnosis and surgical management of testicular seminoma in captive giant panda (Ailuropoda melanoleuca).

A captive adult male giant panda (Guangzhou Chimelong Safari Park, CHINA) presented with azoospermia and enlarged left testicle. A tentative diagnosis of testicular neoplasia was made, and confirmed as testicular seminoma cases by testicular ultrasound, computed tomography (CT), testicular biopsy, and tumor marker examination findings. Based on the diagnostic results, the treatment of choice was surgical resection of the testicular tumor under general anesthesia. And the histopathological findings of the excised neoplasm were consistent with those of testicular seminoma. In addition, no tumor recurrence was observed after surgery, which indicates that our surgical and post-operative treatments were effective. The surgical treatment adopted in this case report is safe for patients and provides the best solution for the diagnosis and treatment of giant panda testicular seminoma. To our knowledge this is the first detailed report of surgical resection of testicular seminoma in the giant panda.

Enhanced recovery management in pediatric pyeloplasty: outcomes in a single institution and tips for improvement.

OBJECTIVE: We report the application of enhanced recovery after surgery (ERAS) regimens to pediatric patients undergoing laparoscopic pyeloplasty (LP), aiming to guide the practice of ERAS in pediatric LP. METHODS: From October 2018, we prospectively implemented a twenty-point ERAS regimen, including a modified LP procedure, for pediatric UPJO patients in a single institution. Data from 2018 to 2021 were collected and analyzed retrospectively. The variables gathered included: demographics, preoperative details and recovery elements. Outcomes were postoperative length of stay (POS), readmission rate, operation time and blood loss. RESULTS: A total of 75 pediatric patients (0-14 years) were included. The mean POS was 2.4 ± 1.4 days, shorter than that in recent studies in China (3.3 ± 1.4 days, 6 (3-16) days). None were redo, and six restenosis (8%) were improved after treatment with ureteral balloon dilatation. The mean operation time was 257.9 ± 54.4 min, and blood loss was 11.8 ± 10.0 ml. In the univariable analysis and multivariable analysis, no external drainage, sacral anesthesia, and withdrawal of the catheter on day one were independently associated with a POS of ≤ 2 d (p < 0.05). CONCLUSION: The implementation of this ERAS protocol for pediatric LP has resulted in a shorter length of stay without a higher readmission rate. Surgery techniques, drainage management and analgesia are the key to further improvement. ERAS for pediatric pyeloplasty should be encouraged.

The role of climate, vegetation, and soil factors on carbon fluxes in Chinese drylands.

Drylands dominate the trend and variability of the land carbon (C) sink. A better understanding of the implications of climate-induced changes in the drylands for C sink-source dynamics is urgently needed. The effect of climate on ecosystem C fluxes (gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem productivity (NEP)) in drylands has been extensively explored, but the roles of other concurrently changing factors, such as vegetation conditions and nutrient availability, remain unclear. We used eddy-covariance C-flux measurements from 45 ecosystems with concurrent information on climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), soil (soil moisture (SM) and soil total nitrogen content (soil N)), and vegetation (leaf area index (LAI) and leaf nitrogen content (LNC)) factors to assess their roles in C fluxes. The results showed that the drylands in China were weak C sinks. GPP and ER were positively correlated with MAP, while they were negatively correlated with MAT. NEP first decreased and then increased with increasing MAT and MAP, and 6.6 °C and 207 mm were the boundaries for the NEP response to MAT and MAP, respectively. SM, soil N, LAI, and MAP were the main factors affecting GPP and ER. However, SM and LNC had the most important influence on NEP. Compared with climate and vegetation factors, soil factors (SM and soil N) had a greater impact on C fluxes in the drylands. Climate factors mainly affected C fluxes by regulating vegetation and soil factors. To accurately estimate the global C balance and predict the response of ecosystems to environmental change, it is necessary to fully consider the discrepant effects of climate, vegetation, and soil factors on C fluxes, as well as the cascade relationships between different factors.

Applications of radiomics-based analysis pipeline for predicting epidermal growth factor receptor mutation status.

BACKGROUND: This study aimed to develop a pipeline for selecting the best feature engineering-based radiomic path to predict epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma in 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). METHODS: The study enrolled 115 lung adenocarcinoma patients with EGFR mutation status from June 2016 and September 2017. We extracted radiomics features by delineating regions-of-interest around the entire tumor in 18F-FDG PET/CT images. The feature engineering-based radiomic paths were built by combining various methods of data scaling, feature selection, and many methods for predictive model-building. Next, a pipeline was developed to select the best path. RESULTS: In the paths from CT images, the highest accuracy was 0.907 (95% confidence interval [CI]: 0.849, 0.966), the highest area under curve (AUC) was 0.917 (95% CI: 0.853, 0.981), and the highest F1 score was 0.908 (95% CI: 0.842, 0.974). In the paths based on PET images, the highest accuracy was 0.913 (95% CI: 0.863, 0.963), the highest AUC was 0.960 (95% CI: 0.926, 0.995), and the highest F1 score was 0.878 (95% CI: 0.815, 0.941). Additionally, a novel evaluation metric was developed to evaluate the comprehensive level of the models. Some feature engineering-based radiomic paths obtained promising results. CONCLUSIONS: The pipeline is capable of selecting the best feature engineering-based radiomic path. Combining various feature engineering-based radiomic paths could compare their performances and identify paths built with the most appropriate methods to predict EGFR-mutant lung adenocarcinoma in 18FDG PET/CT. The pipeline proposed in this work can select the best feature engineering-based radiomic path.

Isolation, characterization, and comparative genomic analysis of vB_BviS-A10Y, a novel bacteriophage from mangrove sediments.

Mangrove is among the most carbon-rich biomes on earth, and viruses are believed to play a significant role in modulating local and global carbon cycling. However, few viruses have been isolated from mangrove sediments to date. Here, we report the isolation of a novel Bacillus phage (named phage vB_BviS-A10Y) from mangrove sediments. Phage vB_BviS-A10Y has a hexameric head with a diameter of ~ 79.22 nm and a tail with a length of ~ 548.56 nm, which are typical features of siphophages. vB_BviS-A10Y initiated host lysis at 3.5 h postinfection with a burst size of 25 plaque-forming units (PFU)/cell. The genome of phage vB_BviS-A10Y is 162,435 bp long with 225 predicted genes, and the GC content is 34.03%. A comparison of the whole genome sequence of phage vB_BviS-A10Y with those of other phages from the NCBI viral genome database showed that phage vB_BviS-A10Y has the highest similarity (73.7% identity with 33% coverage) to Bacillus phage PBC2. Interestingly, abundant auxiliary metabolic genes (AMGs) were identified in the vB_BviS-A10Y genome. The presence of a ß-1,3-glucosyltransferase gene in the phage genome supported our previous hypothesis that mangrove viruses may manipulate carbon cycling directly through their encoded carbohydrate-active enzyme (CAZyme) genes. Therefore, our study will contribute to a better understanding of the diversity and potential roles of viruses in mangrove ecosystems.

Animal Age Affects the Gut Microbiota and Immune System in Captive Koalas (Phascolarctos cinereus).

Gut microbiota is one of the major elements in the control of host health. However, the composition of gut microbiota in koalas has rarely been investigated. Here, we performed 16S rRNA gene sequencing to determine the individual and environmental determinants of gut microbiota diversity and function in 35 fecal samples collected from captive koalas. Meanwhile, blood immune-related cytokine levels were examined by quantitative reverse transcription-PCR to initially explore the relationship between the gut microbiota and the immune system in koalas. The relative abundance of many bacteria, such as Lonepinella koalarum, varies at different ages in koalas and decreases with age. Conversely, Ruminococcus flavefaciens increases with age. Moreover, bacterial pathways involved in lipid metabolism, the biosynthesis of other secondary metabolites, and infectious disease show a significant correlation with age. Age affects the relationship between the microbiota and the host immune system. Among them, the gut microbiota of subadult and aged koalas was closely correlated with CD8ß and CD4, whereas adult koalas were correlated with CLEC4E. We also found that sex, reproductive status, and living environment have little impact on the koala gut microbiota and immune system. These results shed suggest age is a key factor affecting gut microbiota and immunity in captive koalas and thus provide new insight into its role in host development and the host immune system. IMPORTANCE Although we have a preliminary understanding of the gut microbiota of koalas, we lack insight into which factors potentially impact captive koalas. This study creates the largest koala gut microbiota data set in China to date and describes several factors that may affect gut microbiota and the immune system in captive koalas, highlighting that age may be a key factor affecting captive koalas. Moreover, this study is the first to characterize the correlation between gut microbiota and cytokines in koalas. Better treatment strategies for infectious disorders may be possible if we can better understand the interactions between the immune system and the microbiota.

Biodynamic responses of adolescent idiopathic scoliosis exposed to vibration.

Patients with adolescent idiopathic scoliosis suffer severe health issues. The unclear dynamic biomechanical characteristics of scoliosis were needed to be explored to improve the prevention and treatment in clinics. Validated 3D finite element (FE) models of thoracolumbosacral spine (T1-S1) both with and without scoliosis were developed from computed tomography (CT) images. Modal and harmonic analyses were performed to investigate the biomechanical responses of the spinal models to vibration. Resonant frequencies of the scoliotic model were lower than those of the model without scoliosis. Peak amplitudes occurred at vibrational frequencies close to the modal resonant frequencies, which caused the deformed thoracic segment in scoliosis suffered the maximum amplitude. The stresses on vertebrae and intervertebral discs in the scoliotic model derived from vibrations were significantly larger than those in the non-scoliosis model, and heterogeneously concentrated on the scoliotic thoracic segment. In conclusion, the scoliotic spine in the patients with Lenke 1BN scoliosis is more prone to injuries than the non-scoliotic spine while vibrating. Scoliotic thoracic segments in patients with Lenke 1BN scoliosis were the more vulnerable and sensitive component of the T1-S1 spine to vibration than lumbar spines. This study suggested that vibration would impair the scoliotic spines, and patients with Lenke 1BN scoliosis should avoid exposure to vibration, especially the low-frequency vibration.

Ecosystem carbon use efficiency in ecologically vulnerable areas in China: Variation and influencing factors.

Ecologically vulnerable areas (EVAs) are regions with ecosystems that are fragile and vulnerable to degradation under external disturbances, e.g., environmental changes and human activities. A comprehensive understanding of the climate change characteristics of EVAs in China is of great guiding significance for ecological protection and economic development. The ecosystem carbon use efficiency (CUEe) can be defined as the ratio of the net ecosystem productivity (NEP) to gross primary productivity (GPP), one of the most important ecological indicators of ecosystems, representing the capacity for carbon transfer from the atmosphere to a potential ecosystem carbon sink. Understanding the variation in the CUEe and its controlling factors is paramount for regional carbon budget evaluation. Although many CUEe studies have been performed, the spatial variation characteristics and influencing factors of the CUEe are still unclear, especially in EVAs in China. In this study, we synthesized 55 field measurements (3 forestland sites, 37 grassland sites, 6 cropland sites, 9 wetland sites) of the CUEe to examine its variation and influencing factors in EVAs in China. The results showed that the CUEe in EVAs in China ranged from -0.39 to 0.67 with a mean value of 0.20. There were no significant differences in the CUEe among different vegetation types, but there were significant differences in CUEe among the different EVAs (agro-pastoral ecotones < Tibetan Plateau < arid and semiarid areas < Loess Plateau). The CUEe first decreased and then increased with increasing mean annual temperature (MAT), soil pH and soil organic carbon (SOC) and decreased with increasing mean annual precipitation (MAP). The most important factors affecting the CUEe were biotic factors (NEP, GPP, and leaf area index (LAI)). Biotic factors directly affected the CUEe, while climate (MAT and MAP) and soil factors (soil pH and SOC) exerted indirect effects. The results illustrated the comprehensive effect of environmental factors and ecosystem attributes on CUEe variation, which is of great value for the evaluation of regional ecosystem functions.

The Life Cycle Transitions of Temperate Phages: Regulating Factors and Potential Ecological Implications.

Phages are viruses that infect bacteria. They affect various microbe-mediated processes that drive biogeochemical cycling on a global scale. Their influence depends on whether the infection is lysogenic or lytic. Temperate phages have the potential to execute both infection types and thus frequently switch their infection modes in nature, potentially causing substantial impacts on the host-phage community and relevant biogeochemical cycling. Understanding the regulating factors and outcomes of temperate phage life cycle transition is thus fundamental for evaluating their ecological impacts. This review thus systematically summarizes the effects of various factors affecting temperate phage life cycle decisions in both culturable phage-host systems and natural environments. The review further elucidates the ecological implications of the life cycle transition of temperate phages with an emphasis on phage/host fitness, host-phage dynamics, microbe diversity and evolution, and biogeochemical cycles.

Analysis of Factors of Productivity of Tight Conglomerate Reservoirs Based on Random Forest Algorithm.

The tight conglomerate reservoir of Baikouquan formation in the MA 131 well block in the Junggar basin abounds with petroleum reserves, yet the vertical wells in this reservoir have achieved a limited development effect. The tight conglomerate reservoirs have become an important target for exploration and exploitation. The high-efficiency development scheme of a small well spacing three-dimensional (3D) staggered well pattern has been determined by a series of field tests on well pattern and well spacing development. Multistage fracturing with a horizontal well has been demonstrated as the primary development technology. The horizontal wells in the MA 131 small well spacing demonstration area have achieved significantly different development effects, and the major controlling factors for high and stable production of a single well remain unclear. In this study, we proposed an evaluation model of major productivity controlling factors of the tight conglomerate reservoir to provide a reference for oil recovery based on a random forest (RF) machine-learning algorithm. The productivity factors were investigated from two aspects: petrophysical facies that are capable of indicating the genetic mechanism of geological dessert and engineering dessert parameters forming complex fracture networks. Resultantly, the reservoir in the MA 131 well block can be classified into 12 petrophysical facies according to the sedimentary characteristics and diagenesis analysis. The mercury injection curves of a variety of petrophysical facies can be classified into four reservoir quality types. The RF model was trained on 80% of the data to predict the oil well class using the selected features as primary inputs while the remaining 20% of the data were set to test the model performance. The results indicated that the RF model produced excellent results with only 12 misclassifications across the entire data set of 627 samples that represent <2% error. The important evaluation score of the random forest algorithm model showed that the reservoir type, oil saturation, horizontal stress difference, and gravel content are the most important four indicators, with each value exceeding 15%. Brittleness and maximum horizontal stress are considered the least important indexes, with values of less than 5%. Reservoir quality and oil saturation were confirmed as the major controlling factors and material foundation for oil wells' high and stable production. As indicated in this study, stress difference and gravel content are the major controlling factors in the formation of a complex fracture network.

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With the exacerbating disturbances of climate changes and human activities to terrestrial ecosystems, more and more studies realize that ecosystems are at the risk of shifts without warning in structural and functional states and recovery from perturbations require more time. Developing an early warning model to identify critical transition and understanding its ecological mechanism of typical ecosystems have become hotspot in ecological researches. At present, based on theoretical and experimental researches across multiple spatiotemporal scales, a variety of theoretical frameworks and indicators of early warning signals (EWSs) were proposed to signal terrestrial ecosystem critical transition. Here, in order to more thoroughly understand and construct theoretical frameworks and indicators of early warning signals, we reviewed advances in critical transitions from aspects of theoretical methods and processing mechanisms. Catastrophe theory and critical slowing down (CSD) are the two basic theories for early-warning ecosystem state transitions. Self-organization and feedback mechanisms are the primary ecological mechanisms to shape alternative stable state. Understanding cascade effects networks (CENet) among biological and environmental elements, and clarifying the equilibrium relationships between input and output of key ecosystem parameters are theoretical foundation of critical transition model. These theoretical cognitions could provide useful references to early warning of ecosystem disasters, ecological environment management and restoration.

Evaluating image quality and optimal parameters for non-linear blending dual-energy computed tomography images of hepatic portal veins by blending-property-map.

BACKGROUND: Blending technology is usually used to improve quality of dual-energy computed (DECT) images. OBJECTIVES: To evaluate the blended DECT image qualities by employing the Blending-Property-Map (BP-Map) and elucidating the optimal parameters with the highest signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). METHODS: Sixty pairs of 80 kV and 140 kV CT images are blended non-linearly by four methods. Protocol A uses the fixed values of blending width (BW) and blending center (BC); Protocol B uses the values of BW =  (CThepatic portal vein - CThepatic parenchymal) / 2 and BC =  (CThepatic portal vein + CThepatic parenchymal) / 2; Protocol C uses a BW ranging from 10 to 100 HU at an interval of 10 HU and BC = (CThepatic portal vein + CThepatic parenchymal) / 2; Protocol D uses the BP-Map that covers all possible values of BW and BC. RESULTS: When using CT value of adipose tissue as noise, the calculated SNR and CNR of optimal blending width and blending center were 123.22±41.73 and 9.00±3.52, respectively, by the BP-Map in the protocol D. By employing the CT value of back muscle as noise, the SNR and CNR of the best-blended images were 75.90±14.52 and 6.39±2.37, respectively. The subjective score of protocol D was 4.88±0.12. CONCLUSIONS: Compared to traditional blending methods, the BP-Map technique can determine the optimal blending parameter and provide the best-blended images with the highest SNR and CNR.

Use of DWI-FLAIR Mismatch to Estimate the Onset Time in Wake-Up Strokes.

PURPOSE: To compare the MRI characteristics of patients with wake-up ischemic stroke (WUS) and with ischemic stroke with known onset time (clear-onset-time stroke, COS) to clarify the role of diffusion-weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch in estimating the onset time of WUS patients. PATIENTS AND METHODS: Two hundred patients with acute ischemic stroke were selected for complete brain MRI within six hours of symptom onset, including DWI and FLAIR sequences. The patients were divided into WUS (n = 78) and COS (n = 122) groups, based on whether the time of onset was known. The general conditions and imaging characteristics were collected to compare the DWI-FLAIR mismatch features between the two groups at different time intervals. RESULTS: There was no significant difference in the DWI-FLAIR mismatch on MRI within 2 hour after the first found abnormality between the two groups (50.0% vs 71.8%, p = 0.180). With increasing time, the DWI-FLAIR mismatch decreased substantially in the WUS group, while a higher DWI-FLAIR mismatch presence persisted in the COS group within a four-hour interval from the onset of symptoms to the MRI. The DWI-FLAIR mismatch was significantly lower in the WUS group than in the COS group from symptom identification to MRI at 2-3 h, 3-4 h, and 4-5 h intervals (15% vs 60%, 10.5% vs 48%, 6.7% vs 45.4%; p < 0.01). CONCLUSION: Our results suggest that the presence of DWI-FLAIR mismatch within 2 h of the first found abnormality was not significantly different between WUS and COS. Therefore, Patients with WUS within 2 hours after the first detected abnormality may be suitable for intravenous thrombolysis.