BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac ma...BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac magnetic resonance(CMR).This study aimed to determine the prognostic value of LV phenotypes in elderly and non-elderly patients with known or suspected coronary artery disease.METHODS This is a retrospective cohort study among patients who underwent stress or viability CMR.LV phenotypes were classified according to the LV mass index,the LV end-diastolic volume index and the LV mass/volume ratio,into normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy.The primary outcome was a composite of death or heart failure.RESULTS A total of 3289 patients was studied.The average age was 68.0±12.7 years,52.2%of patients were women.Elderly were defined as age≥65 years accounting for 63.9%of the cohort.LV phenotypes were normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy at 74.5%,5.8%,9.2%,and 10.5%,respectively.The median duration of follow-up was 41.4 months.The composite outcome of death or heart failure occurred in 7.3%of patients.The prognostic impact of LV phenotypes was more pronounced in the elderly,with eccentric hypertrophy showing the worst prognosis,followed by concentric hypertrophy and concentric remodeling with the adjusted hazard ratio(95%CI)of 2.37(1.72–3.25),1.53(1.12–2.08),and 1.14(0.76–1.71),respectively,compared to normal phenotype.Patients with eccentric hypertrophy also demonstrated abnormal global longitudinal LV strain,left atrial strain,and extracellular volume fraction.CONCLUSIONS LV phenotypes by CMR independently predict adverse clinical outcomes in elderly patients with known or suspected coronary artery disease.In non-elderly patients,the prognostic value of LV phenotypes was less evident.Assessment of LV phenotypes may be useful for risk stratification.展开更多
Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indice...Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.展开更多
This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the vo...This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the von Kármán theory for membrane large deflection.The membrane’s nonlinear equation is derived by employing the Lagrange equation while accounting for excitations from solar thermal and radiation pressure.The equation is solved via the Rayleigh-Ritz method.The bifurcation diagram of membrane motion is applied to reveal membrane resonance responses under different solar sail rotating frequencies.The displacement time history,phase portrait,Poincarémap,frequency spectrum,and the largest Lyapunov exponent are used to study nonlinear vibrations that occur near resonance regions.The results indicate that time-varying thermal loading excites membrane motions with multiple natural frequencies by the parametric resonance mechanics,leading to the onset of membrane chaotic motion.The membrane’s primary resonance is stimulated in harmonic oscillation by the time-varying radiation pressure.The divergence instability caused by thermal excitation is also illustrated by comparing the membrane’s vibration amplitude with and without thermal excitation.The membrane’s nonlinear vibration characteristics vary significantly with solar illumination angles,the membrane’s thermal expansion coefficients,and structural damping.展开更多
To clarify fluid flow mechanisms and establish effective development conditions in continental shale oil reservoirs,a high-temperature,high-pressure steady-state flow system integrated with nuclear magnetic resonance(...To clarify fluid flow mechanisms and establish effective development conditions in continental shale oil reservoirs,a high-temperature,high-pressure steady-state flow system integrated with nuclear magnetic resonance(NMR)technology has been developed.The apparatus combines sample evacuation,rapid pressurization and saturation,and controlled displacement,enabling systematic investigation of single-phase shale oil flow under representative reservoir conditions.Related experiments allow proper quantification of the activation thresholds and relative contributions of different pore types to flow.A movable fluid index(MFI),defined using dual T_(2) cutoff values,is introduced accordingly and linked to key flow parameters.The results reveal distinct multi-scale characteristics of single-phase shale oil transport,namely micro-scale graded displacement and macro-scale segmented nonlinear behavior.As the injection-production pressure difference increases,flow pathways are activated progressively,beginning with fractures,followed by large and then smaller macropores,leading to a pronounced enhancement in apparent permeability.Although mesopores and micropores contribute little to direct flow,their indirect influence becomes increasingly important,and apparent permeability gradually approaches a stable limit at higher pressure difference.It is also shown that the MFI exhibits a strong negative correlation with the starting pressure gradient and a positive correlation with apparent permeability,providing a rapid and reliable indicator of shale oil flow capacity.Samples containing through-going fractures display consistently higher MFI values and superior flowability compared with those dominated by laminated fractures,highlighting the pivotal role of well-connected fracture networks generated by large-scale hydraulic fracturing in improving shale oil production.展开更多
Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for ...Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for individuals and their families.The majority of existing interventions have been found to be capable of only a slight modification of disease progression or to moderately delay significant functional decline in motor,cognitive,or mental domains.展开更多
Magnetic resonance imaging(MRI)is a powerful tool for diagnosing and monitoring brain diseases,but its low sensitivity can hinder early detection.To address this challenge,we utilized chemical exchange saturation tran...Magnetic resonance imaging(MRI)is a powerful tool for diagnosing and monitoring brain diseases,but its low sensitivity can hinder early detection.To address this challenge,we utilized chemical exchange saturation transfer(CEST)MRI,which greatly enhances sensitivity for detecting low-concentration compounds.In this study,we developed a CEST contrast agent based on a recombinant adeno-associated viruses(rAAVs)encoding the protamine-1(PRM1)MRI reporter gene.CEST MRI revealed that PRM1 contrast agent effectively highlighted caudate putamen region after injection of the rAAVs into the mouse brain,clearly distinguishing it from the surrounding tissue,with no observable damage.This method provides a sensitive,metal-free CEST contrast agent for in vivo brain cell detection,demonstrating potential for both diagnostic and therapeutic applications in brain diseases.展开更多
AIM:To compare spontaneous brain regional activities between diabetic vitreous hemorrhage patients(DVHs)and healthy controls(HCs).METHODS:Thirty-two DVHs and 32 HCs were enrolled in this study.Baseline demographic and...AIM:To compare spontaneous brain regional activities between diabetic vitreous hemorrhage patients(DVHs)and healthy controls(HCs).METHODS:Thirty-two DVHs and 32 HCs were enrolled in this study.Baseline demographic and vision data were compared between groups using an independent sample t-test.Resting-state functional magnetic resonance imaging(rs-fMRI)was used in all participants.fMRI data was obtained and analyzed using MRIcro and SPM8 software.Fractional amplitude of low-frequency fluctuation(fALFF)technology was used to measure regional spontaneous brain activity,and sensitivity was tested using receiver operating characteristic curves(ROCs).The fALFF values were analyzed using REST software and two-sample t-tests were used to compare values between groups.Hospital anxiety and depression scale(HADS)score was assessed in DVHs and Pearson’s correlation was used to test relationships between mean fALFF value and both HADS score and duration of DVH.RESULTS:Except for the best-corrected visual acuity(BCVA)in both eyes,which showed a statistically significant difference(P<0.05),there were no statistically significant differences in the other indicators(P>0.05)between the HCs and DVHs group.Compared with controls,fALFF value was higher in DVH in cerebellum posterior lobe(CPL)and lower in right anterior cingulate cortex(ACC)and right medial orbitofrontal cortex(OFC).In DVH patients,mean fALFF value of CPL was positively correlated with HADS score and duration of diabetes.However,no such correlation was found,for right ACC or right medial OFC.DVH may lead to abnormal activities in certain brain regions related to visual control and mood.CONCLUSION:Visual impairment caused by DVH may lead to adjustment in regional visual brain activities and may be related to depression or reward system processing in some brain regions.展开更多
Scar-related ventricular tachycardia(VT)is a malignant arrhythmia with high mortality rates in patients with cardiomyopathies such as ischemic and dilated cardiomyopathy.[1]While implantable cardioverter defibrillator...Scar-related ventricular tachycardia(VT)is a malignant arrhythmia with high mortality rates in patients with cardiomyopathies such as ischemic and dilated cardiomyopathy.[1]While implantable cardioverter defibrillators(ICD)effectively terminate VT episodes and prevent sudden cardiac death,recurrent ICD discharges may precipitate electrical storms and severely impair quality of life.Radiofrequency catheter ablation is another available treatment for VT but faces challenges in rapidly mapping the critical isthmus during hemodynamically unstable VT.Stereotactic arrhythmia radioablation(STAR)has emerged as a novel,non-invasive,and effective approach for refractory VT over the past decade.展开更多
Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity an...Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity and superparamagnetism.However,it is still a great challenge to prepare ideal iron oxide based contrast agents with high uniformity,excellent water solubility and biocompatibility.In this paper,a novel water-soluble polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(N-vinyl-2-pyrrolidone)(PTMP-PVP)was used as a capping reagent to prepare iron oxide nanoparticles MIONs@PTMP-PVP through one-step co-precipitation of iron precursors in aqueous solution at 100℃.The obtained nanoparticles MIONs@PTMP-PVP had a small size and narrow size distribution,and they were found to be biocompatible as determined through CCK-8 assay and histology analysis.In vivo MRI study demonstrated that the obtained MIONs@PTMP-PVP can be potentially used as an effective T_(2)-weighted MRI contrast agent.展开更多
Cancer has been recognized as one of the leading causes of mortality for decades.Magnetic resonance imaging(MRI)is a powerful imaging technology that has been widely applied in tumor diagnosis.Herein,we report the syn...Cancer has been recognized as one of the leading causes of mortality for decades.Magnetic resonance imaging(MRI)is a powerful imaging technology that has been widely applied in tumor diagnosis.Herein,we report the synthesis of magnetic iron oxide nanoparticles(MIONs)functionalized with multidentate thioether polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(methacrylic acid)(PTMPPMAA).Cytotoxicity assessment via the CCK-8 assay confirmed the low toxicity of the nanoparticles.MRI results showed excellent negative contrast enhancement.Bio-distribution study indicated gradual excretion of the nanoparticles.These MIONs@PTMP-PMAA exhibit strong negative contrast enhancement and present great potential as T_(2)-weighted contrast agents for MRI.展开更多
The integration of a large number of power electronic converters,such as railway power conditioner(RPC),introduces a series of problems,including harmonic interaction,stability issues,and wideband resonance,into the r...The integration of a large number of power electronic converters,such as railway power conditioner(RPC),introduces a series of problems,including harmonic interaction,stability issues,and wideband resonance,into the railway power supply system.To address these challenges,this paper proposes a novel harmonic resonance prevention measure for RPC-network-train interaction system.Firstly,a harmonic model,a parallel resonance impedance model,a series resonance admittance model,and a control stability model are each established for the RPC-network-train interaction system.Secondly,a comprehensive resonance impact factor(CRIF)is proposed to efficiently and accurately identify the key components affecting resonance,and to provide the selection results of optimization parameters for resonance prevention.Next,the initially selected parameters are constrained by the requirements of ripple current,reactive power and stability.Subsequently,the impedance parameters(control parameters and filter parameters)of the RPC are optimized with the objective of reshaping the parallel resonance impedance and series resonance admittance of the RPC-network-train interaction system,ensuring the output current har-monics of RPC meet standards to achieve resonance prevention,while ensuring the stable operation of the RPC.Finally,the proposed resonance prevention measure is verified under both light load and heavy load conditions using a simulation platform and a hardware-in-the-loop experimental platform.展开更多
This article proposes a generalized strongly coupled resonator quartet(GSCRQ)filter along with its synthesis approach.By introducing out-of-band reflection zeros(RZs),the proposed GSCRQ can generate a transmission zer...This article proposes a generalized strongly coupled resonator quartet(GSCRQ)filter along with its synthesis approach.By introducing out-of-band reflection zeros(RZs),the proposed GSCRQ can generate a transmission zero on each side of the passband without negative couplings.The coupling coefficients in this coupling structure change with the positions of the out-of-band RZs.Thus,the GSCRQ configuration admits flexible design solutions.For GSCRQ coaxial combline filters,all couplings can be implemented as inductive couplings,simplifying the design and manufacturing process.In this article,a 6-2 filter in the GSCRQ configuration is synthesized and designed.The simulated results of the designed filter agree very well with the theoretical characteristics.展开更多
A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electro...A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.展开更多
Renal cell carcinoma(RCC)is an aggressive tumor known for its propensity to invade the inferior vena cava(IVC)into the heart.Cardiac metastasis of RCC without IVC involvement is rare.Even rarer is ventricular arrhythm...Renal cell carcinoma(RCC)is an aggressive tumor known for its propensity to invade the inferior vena cava(IVC)into the heart.Cardiac metastasis of RCC without IVC involvement is rare.Even rarer is ventricular arrhythmia as the primary manifestation of cardiac metastasis of RCC with only two cases reported.[1,2]We add to the literature the third case,the diagnosis of which was only possible with cardiac magnetic resonance(CMR).展开更多
Magnetic resonance enterography(MRE)is a non-invasive,radiation-free imaging modality that facilitates the assessment of transmural Crohn’s disease activity.It offers advantages over ileo-colonoscopy,which is limited...Magnetic resonance enterography(MRE)is a non-invasive,radiation-free imaging modality that facilitates the assessment of transmural Crohn’s disease activity.It offers advantages over ileo-colonoscopy,which is limited to mucosal-level evaluation,cannot routinely assess small bowel segments proximal to the terminal ileum,and is unable to detect extra-luminal complications.Despite these ad-vantages,the lack of standardised criteria for defining and appraising radiologic disease activity on MRE has contributed to variability in interpretation and clinical application.In response,multiple MRE-based scoring systems have been developed to quantify radiological Crohn’s disease activity in both luminal and post-operative settings.Radiological disease activity scores specific to luminal Crohn’s disease include the magnetic resonance index of activity(MaRIA),simplified MaRIA,Nancy score,London score,Crohn’s disease magnetic reso-nance imaging(MRI)index,Clermont score,paediatric inflammatory Crohn’s MRE index,MRE global score,MRE index,and modified Clermont score.The MR score and the MRI in Crohn’s disease to predict postoperative recurrence index have been specifically developed to evaluate post-operative disease recurrence in Crohn’s disease.Nevertheless,heterogeneity in scoring parameters,variability in computational complexity,and a lack of consensus regarding optimal score selection,have impeded widespread clinical adoption of radiological disease activity scores.This narrative review aims to summarise the key imaging features of luminal Crohn’s disease,explore their integration into existing MRE scoring indices,and critically compare the structure,strengths,and clinical applicability of each.Furthermore,MRI scores specific to post-operative Crohn’s disease evaluation,and the assessment of cumulative bowel wall damage using the Lemann index will also be discussed.展开更多
Visual assessment of tumor metastatic capacity is crucial for predicting hepatocellular carcinoma(HCC)prognosis and guiding clinical therapeutic approaches.In this study,we developed an enzyme-responsive probe based o...Visual assessment of tumor metastatic capacity is crucial for predicting hepatocellular carcinoma(HCC)prognosis and guiding clinical therapeutic approaches.In this study,we developed an enzyme-responsive probe based on the peptide GK10,which is selectively cleaved by matrix metalloproteinase-9(MMP-9),a critical marker for metastasis in HCC.The GK10 peptide was conjugated with near-infrared fiuorescent molecule IR783,fiuorescent quencher black hole quencher 3(BHQ3),and magnetic resonance(MR)contrast agent DOTA-Gd,forming the IR783-GK10-BHQ3-Gd probe.Upon MMP-9 cleavage of GK10,BHQ3 is released from the probe,thereby amplifying the previously quenched IR783 fiuorescence signal.In vitro experiments demonstrate the probe's impressive detection limit for MMP-9,as low as 1.84 ng/m L.Moreover,in vivo imaging results reveal that the probe can differentiate liver cancers with varying metastatic capacities.The fiuorescence and MR imaging signal intensity of high metastatic HCC are approximately1.2 times greater than that of low metastatic HCC.Thus,this engineered probe holds promise as a valuable tool for evaluating HCC metastatic capacity through fiuorescence-MR dual-mode imaging.展开更多
Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liv...Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liver lesions non-invasive advanced imaging techniques are desirable. Magnetic resonance (MR) is commonly used to identify anatomical lesions, but it is a very versatile technique and also can provide specific information on tumor pathophysiology and metabolism, in particular with the application of MR spectroscopy (MRS). This may include data on the type, grade and stage of tumors, and thus assist in further management of the disease. The purpose of this review is to summarize and discuss the available literature on proton, phosphorus and carbon-13-MRS as performed on primary liver tumors and metastases, with human applications as the main perspective. Upcoming MRSapproaches with potential applications to liver tumors are also included. Since knowledge of some technical background is indispensable to understand the results, a basic introduction of MRS and some technical issues of MRS as applied to tumors and metastases in the liver are described as well. In vivo MR spectroscopy of tumors in a metabolically active organ such as the liver has been demonstrated to provide important information on tumor metabolism, but it also is challenging as compared to applications on some other tissues, in particular in humans, mostly because of its abdominal location where movement may be a disturbing factor.展开更多
BACKGROUND Patients harboring gene mutations like KRAS,NRAS,and BRAF demonstrate highly variable responses to chemotherapy,posing challenges for treatment optimization.Multiparametric magnetic resonance imaging(MRI),w...BACKGROUND Patients harboring gene mutations like KRAS,NRAS,and BRAF demonstrate highly variable responses to chemotherapy,posing challenges for treatment optimization.Multiparametric magnetic resonance imaging(MRI),with its noninvasive capability to assess tumor characteristics in detail,has shown promise in evaluating treatment response and predicting therapeutic outcomes.This technology holds potential for guiding personalized treatment strategies tailored to individual patient profiles,enhancing the precision and effectiveness of colorectal cancer care.AIM To create a multiparametric MRI-based predictive model for assessing chemotherapy efficacy in colorectal cancer patients with gene mutations.METHODS This retrospective study was conducted in a tertiary hospital,analyzing 157 colorectal cancer patients with gene mutations treated between August 2022 and December 2023.Based on chemotherapy outcomes,the patients were categorized into favorable(n=60)and unfavorable(n=50)response groups.Univariate and multivariate logistic regression analyses were performed to identify independent predictors of chemotherapy efficacy.A predictive nomogram was constructed using significant variables,and its performance was assessed using the area under the receiver operating characteristic curve(AUC)in both training and validation sets.RESULTS Univariate analysis identified that tumor differentiation,T2 signal intensity ratio,tumor-to-anal margin distance,and MRI-detected lymph node metastasis as significantly associated with chemotherapy response(P<0.05).Multivariate Logistics regression confirmed these four parameters as independent predictors.The predictive model demonstrated strong discrimination,with an AUC of 0.938(sensitivity:86%;specificity:92%)in the training set,and 0.942(sensitivity:100%;specificity:83%)in the validation set.CONCLUSION We established and validated a multiparametric MRI-based model for predicting chemotherapy response in colorectal cancer patients with gene mutations.This model holds promise for guiding individualized treatment strategies.展开更多
Fetal intracranial tumors are rare,accounting for approximately 0.5%–1.9%of all pediatric tumors,though the true incidence may be underestimated.These tumors often present with distinct histopathological features,ima...Fetal intracranial tumors are rare,accounting for approximately 0.5%–1.9%of all pediatric tumors,though the true incidence may be underestimated.These tumors often present with distinct histopathological features,imaging characteristics,and clinical behavior compared to their postnatal counterparts.This review summarizes the current understanding of the prenatal diagnosis and characterization of fetal brain tumors,with a particular focus on the role of fetal magnetic resonance imaging(MRI).We discuss the advantages of advanced MR sequences in enhancing lesion detection and anatomical delineation following suspicious findings on obstetric ultrasound.Common tumor types encountered in utero—including teratomas,as-trocytomas,medulloblastomas,choroid plexus papillomas,and craniopharyngiomas—are reviewed in terms of imaging fea-tures,differential diagnosis,and clinical implications.Furthermore,the review addresses the diagnostic challenges,prognostic considerations,and the potential role of fetal MRI in guiding perinatal management and parental counseling.展开更多
Diffusion-weighted magnetic resonance imaging(DWI)has become an essential tool in the field of pancreatic magnetic resonance imaging,enabling the detection,characterization,prediction,and evaluation of pancreatic dise...Diffusion-weighted magnetic resonance imaging(DWI)has become an essential tool in the field of pancreatic magnetic resonance imaging,enabling the detection,characterization,prediction,and evaluation of pancreatic diseases.In this article,we review the acquisition parameters,postprocessing techniques,and quantitative methods utilized in pancreatic DWI.Various postprocessing models,including monoexponential,biexponential,stretched exponential and non-Gaussian kurtosis models,as well as deep learning networks,have been used to assess the clinical utility of these models in diagnosing pancreatic diseases.The single-shot echo-planar imaging sequence is the most commonly used sequence for DWI data acquisition in clinical settings,and the apparent diffusion coefficient(ADC)calculated using the monoexponential model is the most widely used quantitative parameter in clinical practice.The repeatability threshold for the ADC of a normal pancreas is 37%for test-retest scans,but the repeatability threshold for pancreatic tumors needs to be further investigated.Complex postprocessing models exploring novel DWI-based biomarkers beyond ADC to assess histological features,and artificial intelligence in DWI postprocessing and data analyses hold promise in the diagnosis of pancreatic diseases.Future work should focus on standardizing protocols,conducting multicentre studies,and exploring variety of methods to improve the accuracy of quantitative DWI results to increase the clinical effectiveness of DWI in patients with pancreatic diseases.展开更多
文摘BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac magnetic resonance(CMR).This study aimed to determine the prognostic value of LV phenotypes in elderly and non-elderly patients with known or suspected coronary artery disease.METHODS This is a retrospective cohort study among patients who underwent stress or viability CMR.LV phenotypes were classified according to the LV mass index,the LV end-diastolic volume index and the LV mass/volume ratio,into normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy.The primary outcome was a composite of death or heart failure.RESULTS A total of 3289 patients was studied.The average age was 68.0±12.7 years,52.2%of patients were women.Elderly were defined as age≥65 years accounting for 63.9%of the cohort.LV phenotypes were normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy at 74.5%,5.8%,9.2%,and 10.5%,respectively.The median duration of follow-up was 41.4 months.The composite outcome of death or heart failure occurred in 7.3%of patients.The prognostic impact of LV phenotypes was more pronounced in the elderly,with eccentric hypertrophy showing the worst prognosis,followed by concentric hypertrophy and concentric remodeling with the adjusted hazard ratio(95%CI)of 2.37(1.72–3.25),1.53(1.12–2.08),and 1.14(0.76–1.71),respectively,compared to normal phenotype.Patients with eccentric hypertrophy also demonstrated abnormal global longitudinal LV strain,left atrial strain,and extracellular volume fraction.CONCLUSIONS LV phenotypes by CMR independently predict adverse clinical outcomes in elderly patients with known or suspected coronary artery disease.In non-elderly patients,the prognostic value of LV phenotypes was less evident.Assessment of LV phenotypes may be useful for risk stratification.
基金supported by the National Natural Science Foundation of China,No.82071909(to GF)the Natural Science Foundation of Liaoning Province,No.2023-MS-07(to HL)。
文摘Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.
基金supported by the Science Fund of NPU-Duke China Seeds Program(Grant No.119003067)the CAST-BISEE Fund(Grant No.MC010175)+1 种基金the Project of National Natural Science Foundation of China(Grant No.12372233)the“111”project of China(Grant No.B17037).
文摘This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the von Kármán theory for membrane large deflection.The membrane’s nonlinear equation is derived by employing the Lagrange equation while accounting for excitations from solar thermal and radiation pressure.The equation is solved via the Rayleigh-Ritz method.The bifurcation diagram of membrane motion is applied to reveal membrane resonance responses under different solar sail rotating frequencies.The displacement time history,phase portrait,Poincarémap,frequency spectrum,and the largest Lyapunov exponent are used to study nonlinear vibrations that occur near resonance regions.The results indicate that time-varying thermal loading excites membrane motions with multiple natural frequencies by the parametric resonance mechanics,leading to the onset of membrane chaotic motion.The membrane’s primary resonance is stimulated in harmonic oscillation by the time-varying radiation pressure.The divergence instability caused by thermal excitation is also illustrated by comparing the membrane’s vibration amplitude with and without thermal excitation.The membrane’s nonlinear vibration characteristics vary significantly with solar illumination angles,the membrane’s thermal expansion coefficients,and structural damping.
基金supported by the National Science and Technology Major Project of China(Grant No.2024ZD 1004302)the Key Scientific and Technological Research project of SINOPEC(Grant No.P25186).
文摘To clarify fluid flow mechanisms and establish effective development conditions in continental shale oil reservoirs,a high-temperature,high-pressure steady-state flow system integrated with nuclear magnetic resonance(NMR)technology has been developed.The apparatus combines sample evacuation,rapid pressurization and saturation,and controlled displacement,enabling systematic investigation of single-phase shale oil flow under representative reservoir conditions.Related experiments allow proper quantification of the activation thresholds and relative contributions of different pore types to flow.A movable fluid index(MFI),defined using dual T_(2) cutoff values,is introduced accordingly and linked to key flow parameters.The results reveal distinct multi-scale characteristics of single-phase shale oil transport,namely micro-scale graded displacement and macro-scale segmented nonlinear behavior.As the injection-production pressure difference increases,flow pathways are activated progressively,beginning with fractures,followed by large and then smaller macropores,leading to a pronounced enhancement in apparent permeability.Although mesopores and micropores contribute little to direct flow,their indirect influence becomes increasingly important,and apparent permeability gradually approaches a stable limit at higher pressure difference.It is also shown that the MFI exhibits a strong negative correlation with the starting pressure gradient and a positive correlation with apparent permeability,providing a rapid and reliable indicator of shale oil flow capacity.Samples containing through-going fractures display consistently higher MFI values and superior flowability compared with those dominated by laminated fractures,highlighting the pivotal role of well-connected fracture networks generated by large-scale hydraulic fracturing in improving shale oil production.
文摘Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for individuals and their families.The majority of existing interventions have been found to be capable of only a slight modification of disease progression or to moderately delay significant functional decline in motor,cognitive,or mental domains.
基金financially supported by the National Natural Science Foundation of China(82127802,22374157)Strategic Priority Research Program,CAS(XDB0540000,XDC0170000)CAS Youth Interdisciplinary Team(JCTD-2022-13).In addition,Xin Zhou acknowledges the support from the Tencent Foundation through the XPLORER PRIZE.
文摘Magnetic resonance imaging(MRI)is a powerful tool for diagnosing and monitoring brain diseases,but its low sensitivity can hinder early detection.To address this challenge,we utilized chemical exchange saturation transfer(CEST)MRI,which greatly enhances sensitivity for detecting low-concentration compounds.In this study,we developed a CEST contrast agent based on a recombinant adeno-associated viruses(rAAVs)encoding the protamine-1(PRM1)MRI reporter gene.CEST MRI revealed that PRM1 contrast agent effectively highlighted caudate putamen region after injection of the rAAVs into the mouse brain,clearly distinguishing it from the surrounding tissue,with no observable damage.This method provides a sensitive,metal-free CEST contrast agent for in vivo brain cell detection,demonstrating potential for both diagnostic and therapeutic applications in brain diseases.
基金Supported by National Natural Science Foundation of China(No.82160195,No.82460203)Zhejiang Traditional Chinese Medicine Science and Technology Plan Project(No.2025ZR172).
文摘AIM:To compare spontaneous brain regional activities between diabetic vitreous hemorrhage patients(DVHs)and healthy controls(HCs).METHODS:Thirty-two DVHs and 32 HCs were enrolled in this study.Baseline demographic and vision data were compared between groups using an independent sample t-test.Resting-state functional magnetic resonance imaging(rs-fMRI)was used in all participants.fMRI data was obtained and analyzed using MRIcro and SPM8 software.Fractional amplitude of low-frequency fluctuation(fALFF)technology was used to measure regional spontaneous brain activity,and sensitivity was tested using receiver operating characteristic curves(ROCs).The fALFF values were analyzed using REST software and two-sample t-tests were used to compare values between groups.Hospital anxiety and depression scale(HADS)score was assessed in DVHs and Pearson’s correlation was used to test relationships between mean fALFF value and both HADS score and duration of DVH.RESULTS:Except for the best-corrected visual acuity(BCVA)in both eyes,which showed a statistically significant difference(P<0.05),there were no statistically significant differences in the other indicators(P>0.05)between the HCs and DVHs group.Compared with controls,fALFF value was higher in DVH in cerebellum posterior lobe(CPL)and lower in right anterior cingulate cortex(ACC)and right medial orbitofrontal cortex(OFC).In DVH patients,mean fALFF value of CPL was positively correlated with HADS score and duration of diabetes.However,no such correlation was found,for right ACC or right medial OFC.DVH may lead to abnormal activities in certain brain regions related to visual control and mood.CONCLUSION:Visual impairment caused by DVH may lead to adjustment in regional visual brain activities and may be related to depression or reward system processing in some brain regions.
文摘Scar-related ventricular tachycardia(VT)is a malignant arrhythmia with high mortality rates in patients with cardiomyopathies such as ischemic and dilated cardiomyopathy.[1]While implantable cardioverter defibrillators(ICD)effectively terminate VT episodes and prevent sudden cardiac death,recurrent ICD discharges may precipitate electrical storms and severely impair quality of life.Radiofrequency catheter ablation is another available treatment for VT but faces challenges in rapidly mapping the critical isthmus during hemodynamically unstable VT.Stereotactic arrhythmia radioablation(STAR)has emerged as a novel,non-invasive,and effective approach for refractory VT over the past decade.
基金financially supported by the International Cooperation Program from the Ministry of Science and Technology of Hubei Province(No.2023EHA069)Shenzhen Science and Technology Program(No.JCYJ20230807143702005)National Foreign Experts Program(No.G2022027015L)。
文摘Magnetic resonance imaging(MRI)is one of the most widely used diagnostic techniques.Iron oxide nanoparticles,as a promising kind of contrast agents,have attracted intense research interest due to their low toxicity and superparamagnetism.However,it is still a great challenge to prepare ideal iron oxide based contrast agents with high uniformity,excellent water solubility and biocompatibility.In this paper,a novel water-soluble polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(N-vinyl-2-pyrrolidone)(PTMP-PVP)was used as a capping reagent to prepare iron oxide nanoparticles MIONs@PTMP-PVP through one-step co-precipitation of iron precursors in aqueous solution at 100℃.The obtained nanoparticles MIONs@PTMP-PVP had a small size and narrow size distribution,and they were found to be biocompatible as determined through CCK-8 assay and histology analysis.In vivo MRI study demonstrated that the obtained MIONs@PTMP-PVP can be potentially used as an effective T_(2)-weighted MRI contrast agent.
基金financially supported by the International Cooperation Program of the Ministry of Science and Technology of Hubei Province(No.2023EHA069)Shenzhen Science and Technology Program(No.JCYJ20230807143702005)+1 种基金National Foreign Experts Program(No.G2022027015L)the National Natural Science Foundation of China(No.82302265).
文摘Cancer has been recognized as one of the leading causes of mortality for decades.Magnetic resonance imaging(MRI)is a powerful imaging technology that has been widely applied in tumor diagnosis.Herein,we report the synthesis of magnetic iron oxide nanoparticles(MIONs)functionalized with multidentate thioether polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-poly(methacrylic acid)(PTMPPMAA).Cytotoxicity assessment via the CCK-8 assay confirmed the low toxicity of the nanoparticles.MRI results showed excellent negative contrast enhancement.Bio-distribution study indicated gradual excretion of the nanoparticles.These MIONs@PTMP-PMAA exhibit strong negative contrast enhancement and present great potential as T_(2)-weighted contrast agents for MRI.
基金supported in part by the National Natural Science Foundation of China under Grant No.52277126.
文摘The integration of a large number of power electronic converters,such as railway power conditioner(RPC),introduces a series of problems,including harmonic interaction,stability issues,and wideband resonance,into the railway power supply system.To address these challenges,this paper proposes a novel harmonic resonance prevention measure for RPC-network-train interaction system.Firstly,a harmonic model,a parallel resonance impedance model,a series resonance admittance model,and a control stability model are each established for the RPC-network-train interaction system.Secondly,a comprehensive resonance impact factor(CRIF)is proposed to efficiently and accurately identify the key components affecting resonance,and to provide the selection results of optimization parameters for resonance prevention.Next,the initially selected parameters are constrained by the requirements of ripple current,reactive power and stability.Subsequently,the impedance parameters(control parameters and filter parameters)of the RPC are optimized with the objective of reshaping the parallel resonance impedance and series resonance admittance of the RPC-network-train interaction system,ensuring the output current har-monics of RPC meet standards to achieve resonance prevention,while ensuring the stable operation of the RPC.Finally,the proposed resonance prevention measure is verified under both light load and heavy load conditions using a simulation platform and a hardware-in-the-loop experimental platform.
基金supported by the National Natural Science Foundation of China under Grant No.62471366。
文摘This article proposes a generalized strongly coupled resonator quartet(GSCRQ)filter along with its synthesis approach.By introducing out-of-band reflection zeros(RZs),the proposed GSCRQ can generate a transmission zero on each side of the passband without negative couplings.The coupling coefficients in this coupling structure change with the positions of the out-of-band RZs.Thus,the GSCRQ configuration admits flexible design solutions.For GSCRQ coaxial combline filters,all couplings can be implemented as inductive couplings,simplifying the design and manufacturing process.In this article,a 6-2 filter in the GSCRQ configuration is synthesized and designed.The simulated results of the designed filter agree very well with the theoretical characteristics.
基金supported by the Natural Science Foundation of Tianjin City (No.19JCYBJC17000)the National Natural Science Foundation of China (No.11905159)。
文摘A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.
文摘Renal cell carcinoma(RCC)is an aggressive tumor known for its propensity to invade the inferior vena cava(IVC)into the heart.Cardiac metastasis of RCC without IVC involvement is rare.Even rarer is ventricular arrhythmia as the primary manifestation of cardiac metastasis of RCC with only two cases reported.[1,2]We add to the literature the third case,the diagnosis of which was only possible with cardiac magnetic resonance(CMR).
文摘Magnetic resonance enterography(MRE)is a non-invasive,radiation-free imaging modality that facilitates the assessment of transmural Crohn’s disease activity.It offers advantages over ileo-colonoscopy,which is limited to mucosal-level evaluation,cannot routinely assess small bowel segments proximal to the terminal ileum,and is unable to detect extra-luminal complications.Despite these ad-vantages,the lack of standardised criteria for defining and appraising radiologic disease activity on MRE has contributed to variability in interpretation and clinical application.In response,multiple MRE-based scoring systems have been developed to quantify radiological Crohn’s disease activity in both luminal and post-operative settings.Radiological disease activity scores specific to luminal Crohn’s disease include the magnetic resonance index of activity(MaRIA),simplified MaRIA,Nancy score,London score,Crohn’s disease magnetic reso-nance imaging(MRI)index,Clermont score,paediatric inflammatory Crohn’s MRE index,MRE global score,MRE index,and modified Clermont score.The MR score and the MRI in Crohn’s disease to predict postoperative recurrence index have been specifically developed to evaluate post-operative disease recurrence in Crohn’s disease.Nevertheless,heterogeneity in scoring parameters,variability in computational complexity,and a lack of consensus regarding optimal score selection,have impeded widespread clinical adoption of radiological disease activity scores.This narrative review aims to summarise the key imaging features of luminal Crohn’s disease,explore their integration into existing MRE scoring indices,and critically compare the structure,strengths,and clinical applicability of each.Furthermore,MRI scores specific to post-operative Crohn’s disease evaluation,and the assessment of cumulative bowel wall damage using the Lemann index will also be discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.32025021,31971292,32111540257)the Zhejiang Province Financial Supporting(Nos.2020C03110 and 2023C04017)the Key Scientific and Technological Special Project of Ningbo City(No.2020Z094)。
文摘Visual assessment of tumor metastatic capacity is crucial for predicting hepatocellular carcinoma(HCC)prognosis and guiding clinical therapeutic approaches.In this study,we developed an enzyme-responsive probe based on the peptide GK10,which is selectively cleaved by matrix metalloproteinase-9(MMP-9),a critical marker for metastasis in HCC.The GK10 peptide was conjugated with near-infrared fiuorescent molecule IR783,fiuorescent quencher black hole quencher 3(BHQ3),and magnetic resonance(MR)contrast agent DOTA-Gd,forming the IR783-GK10-BHQ3-Gd probe.Upon MMP-9 cleavage of GK10,BHQ3 is released from the probe,thereby amplifying the previously quenched IR783 fiuorescence signal.In vitro experiments demonstrate the probe's impressive detection limit for MMP-9,as low as 1.84 ng/m L.Moreover,in vivo imaging results reveal that the probe can differentiate liver cancers with varying metastatic capacities.The fiuorescence and MR imaging signal intensity of high metastatic HCC are approximately1.2 times greater than that of low metastatic HCC.Thus,this engineered probe holds promise as a valuable tool for evaluating HCC metastatic capacity through fiuorescence-MR dual-mode imaging.
基金Supported by A grant from the Dutch Cancer Society (KWF Kankerbestrijding), No. KUN 2008-4098
文摘Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liver lesions non-invasive advanced imaging techniques are desirable. Magnetic resonance (MR) is commonly used to identify anatomical lesions, but it is a very versatile technique and also can provide specific information on tumor pathophysiology and metabolism, in particular with the application of MR spectroscopy (MRS). This may include data on the type, grade and stage of tumors, and thus assist in further management of the disease. The purpose of this review is to summarize and discuss the available literature on proton, phosphorus and carbon-13-MRS as performed on primary liver tumors and metastases, with human applications as the main perspective. Upcoming MRSapproaches with potential applications to liver tumors are also included. Since knowledge of some technical background is indispensable to understand the results, a basic introduction of MRS and some technical issues of MRS as applied to tumors and metastases in the liver are described as well. In vivo MR spectroscopy of tumors in a metabolically active organ such as the liver has been demonstrated to provide important information on tumor metabolism, but it also is challenging as compared to applications on some other tissues, in particular in humans, mostly because of its abdominal location where movement may be a disturbing factor.
基金Supported by Shenzhen High-level Hospital Construction Fund.
文摘BACKGROUND Patients harboring gene mutations like KRAS,NRAS,and BRAF demonstrate highly variable responses to chemotherapy,posing challenges for treatment optimization.Multiparametric magnetic resonance imaging(MRI),with its noninvasive capability to assess tumor characteristics in detail,has shown promise in evaluating treatment response and predicting therapeutic outcomes.This technology holds potential for guiding personalized treatment strategies tailored to individual patient profiles,enhancing the precision and effectiveness of colorectal cancer care.AIM To create a multiparametric MRI-based predictive model for assessing chemotherapy efficacy in colorectal cancer patients with gene mutations.METHODS This retrospective study was conducted in a tertiary hospital,analyzing 157 colorectal cancer patients with gene mutations treated between August 2022 and December 2023.Based on chemotherapy outcomes,the patients were categorized into favorable(n=60)and unfavorable(n=50)response groups.Univariate and multivariate logistic regression analyses were performed to identify independent predictors of chemotherapy efficacy.A predictive nomogram was constructed using significant variables,and its performance was assessed using the area under the receiver operating characteristic curve(AUC)in both training and validation sets.RESULTS Univariate analysis identified that tumor differentiation,T2 signal intensity ratio,tumor-to-anal margin distance,and MRI-detected lymph node metastasis as significantly associated with chemotherapy response(P<0.05).Multivariate Logistics regression confirmed these four parameters as independent predictors.The predictive model demonstrated strong discrimination,with an AUC of 0.938(sensitivity:86%;specificity:92%)in the training set,and 0.942(sensitivity:100%;specificity:83%)in the validation set.CONCLUSION We established and validated a multiparametric MRI-based model for predicting chemotherapy response in colorectal cancer patients with gene mutations.This model holds promise for guiding individualized treatment strategies.
基金supported by the Medical Innovation Research Special Project of Science and Technology Commission of Shanghai Municipality(Grant/Award Number:23Y11907800)Fundamental Research Funds for the Central Universities(Grant/Award Number:YG2023ZD22)Shanghai Key Laboratory of Child Brain and Development(Grant/Award Number:24dz2260100).
文摘Fetal intracranial tumors are rare,accounting for approximately 0.5%–1.9%of all pediatric tumors,though the true incidence may be underestimated.These tumors often present with distinct histopathological features,imaging characteristics,and clinical behavior compared to their postnatal counterparts.This review summarizes the current understanding of the prenatal diagnosis and characterization of fetal brain tumors,with a particular focus on the role of fetal magnetic resonance imaging(MRI).We discuss the advantages of advanced MR sequences in enhancing lesion detection and anatomical delineation following suspicious findings on obstetric ultrasound.Common tumor types encountered in utero—including teratomas,as-trocytomas,medulloblastomas,choroid plexus papillomas,and craniopharyngiomas—are reviewed in terms of imaging fea-tures,differential diagnosis,and clinical implications.Furthermore,the review addresses the diagnostic challenges,prognostic considerations,and the potential role of fetal MRI in guiding perinatal management and parental counseling.
基金Supported by National Natural Science Foundation of China,No.62472315Shanghai Science and Technology Innovation Action Plan Medical Innovation Research Project,No.20Y11912500.
文摘Diffusion-weighted magnetic resonance imaging(DWI)has become an essential tool in the field of pancreatic magnetic resonance imaging,enabling the detection,characterization,prediction,and evaluation of pancreatic diseases.In this article,we review the acquisition parameters,postprocessing techniques,and quantitative methods utilized in pancreatic DWI.Various postprocessing models,including monoexponential,biexponential,stretched exponential and non-Gaussian kurtosis models,as well as deep learning networks,have been used to assess the clinical utility of these models in diagnosing pancreatic diseases.The single-shot echo-planar imaging sequence is the most commonly used sequence for DWI data acquisition in clinical settings,and the apparent diffusion coefficient(ADC)calculated using the monoexponential model is the most widely used quantitative parameter in clinical practice.The repeatability threshold for the ADC of a normal pancreas is 37%for test-retest scans,but the repeatability threshold for pancreatic tumors needs to be further investigated.Complex postprocessing models exploring novel DWI-based biomarkers beyond ADC to assess histological features,and artificial intelligence in DWI postprocessing and data analyses hold promise in the diagnosis of pancreatic diseases.Future work should focus on standardizing protocols,conducting multicentre studies,and exploring variety of methods to improve the accuracy of quantitative DWI results to increase the clinical effectiveness of DWI in patients with pancreatic diseases.
