Zero-and ultralow-field nuclear magnetic resonance(ZULF NMR)has experienced rapid development and provides an excellent tool for diverse research fields ranging from materials science and quantum information processin...Zero-and ultralow-field nuclear magnetic resonance(ZULF NMR)has experienced rapid development and provides an excellent tool for diverse research fields ranging from materials science and quantum information processing to fundamental physics.The detection of ZULF NMR signals in samples with natural abundance remains a challenging endeavor,due to the limited sensitivity of NMR detectors and thermal polarization.In this work,we demonstrate a femtotesla(fT)Potassium spin-exchange relaxation-free(SERF)magnetometer designed for ZULF NMR detection.A Potassium vapor cell with high buffer gas pressure and high atomic number density is used in the magnetometer.With absorption spectroscopy and SERF effect,the key parameters of the vapor cell are characterized and applied to optimize the magnetometer sensitivity.To combine our SERF magnetometer and ZULF NMR detection,a custom-made vacuum chamber is employed to keep NMR sample close to the magnetometer cell and protect the sample from undesired heating effects.Gradiometric measurement is performed to greatly reduce the magnetic noise.With the phase calibration applied,the gradiometric measurement achieves 7-fold enhancement in magnetic-field sensitivity compared to the single channel and has a magnetic noise floor of 1.2 fT/Hz^(1/2).Our SERF magnetometer exhibits high sensitivity and is promising to realize ZULF NMR detection of samples with natural abundance.展开更多
BACKGROUND Esophageal cancer(EC)is one of the most prevalent malignant gastrointestinal tumors;accurate prediction of EC staging has high significance before treatment.AIM To explore a rational radiomic approach for p...BACKGROUND Esophageal cancer(EC)is one of the most prevalent malignant gastrointestinal tumors;accurate prediction of EC staging has high significance before treatment.AIM To explore a rational radiomic approach for predicting preoperative staging of EC based on magnetic resonance imaging(MRI).METHODS This retrospective study included 210 patients with pathologically confirmed EC,randomly divided into a primary cohort(n=147)and a validation cohort(n=63)in a ratio of 7:3.All patients underwent a preoperative MRI scan from the neck to the abdomen.High-throughput and quantitative radiomics features were extracted from T2-weighted imaging(T2WI)and gadolinium contrast-enhanced T1-weighted imaging(T1WI)-Gd images.Radiomics signatures were selected using minimal redundancy maximal relevance and the least absolute shrinkage and selection operator.Then a logistic regression model was built to predict the EC stages.The diagnostic performance of the radiomics model for discriminating between stages Ⅰ-Ⅱ and Ⅲ-Ⅳ was evaluated using the area under the curve(AUC),sensitivity(SEN),and specificity(SPE).RESULTS A total of 214 radiomics features were extracted.Following feature dimension reduction,the T1WI and T2WI sequences were retained,and 14 features from the T1WI sequence and 3 features from the T2WI sequence were selected to construct radiomics signatures.The radiomics signature combining T2WI with T1WI-Gd demonstrated superior discrimination of stages in the validation cohort(AUC:0.851;SEN:0.697;SPE:0.793),which outperformed single-sequence models(AUC:0.779,0.844;SEN:0.667,0.636;SPE:0.8,0.8).CONCLUSION MRI-based radiomics signatures could identify EC stages before treatment,which could serve as a noninvasive and quantitative approach aiding personalized treatment planning.展开更多
Magnetic resonance imaging(MRI)plays an important role in medical diagnosis,generating petabytes of image data annually in large hospitals.This voluminous data stream requires a significant amount of network bandwidth...Magnetic resonance imaging(MRI)plays an important role in medical diagnosis,generating petabytes of image data annually in large hospitals.This voluminous data stream requires a significant amount of network bandwidth and extensive storage infrastructure.Additionally,local data processing demands substantial manpower and hardware investments.Data isolation across different healthcare institutions hinders crossinstitutional collaboration in clinics and research.In this work,we anticipate an innovative MRI system and its four generations that integrate emerging distributed cloud computing,6G bandwidth,edge computing,federated learning,and blockchain technology.This system is called Cloud-MRI,aiming at solving the problems of MRI data storage security,transmission speed,artificial intelligence(AI)algorithm maintenance,hardware upgrading,and collaborative work.The workflow commences with the transformation of k-space raw data into the standardized Imaging Society for Magnetic Resonance in Medicine Raw Data(ISMRMRD)format.Then,the data are uploaded to the cloud or edge nodes for fast image reconstruction,neural network training,and automatic analysis.Then,the outcomes are seamlessly transmitted to clinics or research institutes for diagnosis and other services.The Cloud-MRI system will save the raw imaging data,reduce the risk of data loss,facilitate inter-institutional medical collaboration,and finally improve diagnostic accuracy and work efficiency.展开更多
BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diff...BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.展开更多
Cardiac magnetic resonance(CMR),a non-radiation based type of examination,can achieve the simultaneous comprehensive multi-parameter,multi-plane,and multi-sequence evaluation of the anatomical structure of the heart;a...Cardiac magnetic resonance(CMR),a non-radiation based type of examination,can achieve the simultaneous comprehensive multi-parameter,multi-plane,and multi-sequence evaluation of the anatomical structure of the heart;and at the same time,determine systolic and diastolic function,and blood perfusion and tissue characteristics.Traditional late gadolinium enhancement imaging based on CMR reflects focal replacement fibrosis,in contrast to normal myocardial signal intensity,but cannot effectively identify diffuse myocardial fibrosis.T1 mapping and its derived extracellular volume fraction can be used to quantitatively analyze the extracellular space in myocardial tissue and evaluate diffuse myocardial interstitial fibrosis that is invisible to the naked eye.Diffusion tensor imaging reveals the direction of cardiomyocyte aggregates by quantifying the anisotropy of water molecule diffusion,and can be applied to evaluate the integrity of myocardial tissue and arrangement structure of myocardial microstructural characteristics.On the basis of the micro-motion of myocardial tissue,feature tracking analysis decomposes myocardial deformation into three dimensions of micro-mechanical changes,and can identify early systolic and diastolic dysfunction before heart enlargement or ejection fraction reduction.This Commentary discusses current research advances in these new techniques,as well as their clinical application prospects and limitations for non-ischemic cardiomyopathies.展开更多
BACKGROUND Magnetic resonance imaging(MRI)combined with serum endothelin and galactagoglobin-3(Gal-3)can improve the clinical diagnosis of diabetes mellitus complicated with cerebral infarction.AIM To analyze the clin...BACKGROUND Magnetic resonance imaging(MRI)combined with serum endothelin and galactagoglobin-3(Gal-3)can improve the clinical diagnosis of diabetes mellitus complicated with cerebral infarction.AIM To analyze the clinical value of MRI combined with serum endolipin and Gal-3 for the diagnosis of cerebral infarction in the elderly with diabetes mellitus.METHODS One hundred and fifty patients with acute cerebral infarction hospitalized between January 2021 and December 2023 were divided into two groups according to comorbid diabetes mellitus,including 62 and 88 cases in the diabetic and nondiabetic cerebral infarction groups.Serum samples were collected to detect the expression of serum endolipoxins,and Gal-3,and cranial MRI was performed at admission.Differences between the two groups were compared to analyze the diagnostic value of these parameters.RESULTS Serum endolipin and Gal-3 expression were higher in the diabetic cerebral infarction group(P<0.05).The arterial wall area,vessel area,normalized wall index,and lumen stenosis rate were higher in the diabetic cerebral infarction group,while the rate of arterial lumen moderate and severe stenosis was 48.39% higher(36.36%,P<0.05).The percentage of large(29.03%)and multiple infarcts(33.87%)in the diabetic cerebral infarction group was higher(13.64% and 20.45%),and the incidence rate of lacunar infarcts was lower(37.10%vs 65.91%)(P<0.05).The total incidence of arterial plaque in patients in the diabetic cerebral infarction group was 96.77% higher(69.32%),while the incidence of necrotic lipid core plaque was 58.06%higher(26.14%)(P<0.05).Receiver operating characteristic curve analysis was performed to assess the diagnosis utility of these techniques.MRI in combination with serum endoglin and Gal-3 had the highest area under the curve,the Yoden index,sensitivity and specificity(P<0.05).CONCLUSION The expression of serum endolipin and Gal-3 in elderly patients with diabetes mellitus with cerebral infarction showed an elevated trend,and the degree of luminal stenosis was severe.MRI predominantly revealed large and multiple infarct foci.This combined index examination can improve the clinical diagnosis of diabetes mellitus combined with cerebral infarction.展开更多
The field of radiology is currently undergoing revolutionary changes owing to the increasing application of artificial intelligence(AI).This scoping review identifies and summarizes the technical methods and clinical ...The field of radiology is currently undergoing revolutionary changes owing to the increasing application of artificial intelligence(AI).This scoping review identifies and summarizes the technical methods and clinical applications of AI applied to magnetic resonance imaging of cerebrovascular diseases(CVDs).Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews was adopted and articles listed in PubMed and Cochrane databases from January 1,2018 to December 31,2023,were assessed.In total,67 articles met the eligibility criteria.We obtained a general overview of the field,including lesion types,sample sizes,data sources,and databases and found that nearly half of the studies used multisequence magnetic resonance as the input.Both classical machine learning and deep learning were widely used.The evaluation metrics varied according to the five main algorithm tasks of classification,detection,segmentation,estimation,and generation.Cross-validation was primarily used with only one third of the included studies using external validation.We also illustrate the key questions of the CVD research studies and grade the clinical utility of their AI solutions.Although most attention is devoted to improving the performance of AI models,this scoping review provides information on the availability of algorithms,reli-ability of external validations,and consistency of evaluation metrics and may facilitate improved clinical applicability and acceptance.展开更多
Ion cyclotron resonance heating(ICRH)stands out as a widely utilized and cost-effective auxiliary method for plasma heating,bearing significant importance in achieving high-performance discharges in p-^(11)B plasmas.I...Ion cyclotron resonance heating(ICRH)stands out as a widely utilized and cost-effective auxiliary method for plasma heating,bearing significant importance in achieving high-performance discharges in p-^(11)B plasmas.In light of the specific context of p-^(11)B plasma in the EHL-2 device,we conducted a comprehensive scan of the fundamental physical parameters of the antenna using the full-wave simulation program TORIC.Our preliminary result indicated that for p-^(11)B plasma,optimal ion heating parameters include a frequency of 40 MHz,with a high toroidal mode number like N_(?)=28 to heat the majority H ions.In addition,we discussed the impact of concentration of minority ion species on ion cyclotron resonance heating when^(11)B serves as the heavy minority species.The significant difference in charge-to-mass ratio between boron and hydrogen ions results in a considerable distance between the hybrid resonance layer and the tow inverted cyclotron resonance layer,necessitating a quite low boron ion concentration to achieve effective minority heating.We also considered another method of direct heating of hydrogen ions in the presence of boron ion minority.It is found that at appropriate boron ion concentrations(X(^(11)B)~17%),the position of the hybrid resonance layer approaches that of the hydrogen ion cyclotron resonance layer,thereby altering the polarization at this position and significantly enhancing hydrogen ion fundamental absorption.展开更多
A total of 29 patients were treated within 48 hours after acute subcortical cerebral infarction with Xuesaitong or Xuesaitong plus human urinary kallidinogenase for 14 days. Neurological deficits, activity of daily li...A total of 29 patients were treated within 48 hours after acute subcortical cerebral infarction with Xuesaitong or Xuesaitong plus human urinary kallidinogenase for 14 days. Neurological deficits, activity of daily living, and evaluations of distal upper limb motor functions at the 6-month follow-up showed that patients treated with Xuesaitong plus human urinary kallidinogenase recovered better than with Xuesaitong alone. In addition, functional MRI revealed that activation sites were primarily at the ipsilesional side of injury in all patients. Human urinary kallidinogenase induced hyperactivation of the ipsilesional primary sensorimotor cortex, premotor cortex, supplementary motor area, and contralesional posterior parietal cortex. Results showed that human urinary kallidinogenase improved symptoms of neurological deficiency by enhancing remodeling of long-term cortical motor function in patients with acute cerebral infarction.展开更多
Prostate cancer and prostatic calcifications have a high incidence in elderly men. We aimed to investigate the diagnostic capabilities of susceptibility-weighted imaging in detecting prostate cancer and prostatic calc...Prostate cancer and prostatic calcifications have a high incidence in elderly men. We aimed to investigate the diagnostic capabilities of susceptibility-weighted imaging in detecting prostate cancer and prostatic calcifications. A total number of 156 men, including 34 with prostate cancer and 122 with benign prostate were enrolled in this study. Computed tomography, conventional magnetic resonance imaging, diffusion-weighted imaging, and susceptibility-weighted imaging were performed on all the patients. One hundred and twelve prostatic calcifications were detected in 87 patients. The sensitivities and specificities of the conventional magnetic resonance imaging, apparent diffusion coefficient, and susceptibility-filtered phase images in detecting prostate cancer and prostatic calcifications were calculated. McNemar＇s Chi-square test was used to compare the differences in sensitivities and specificities between the techniques. The results showed that the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic cancer were greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient （P 〈 0.05）. In addition, the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic calcifications were comparable to that of computed tomography and greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient （P 〈 0.05）. Given the high incidence of susceptibility-weighted imaging （SWl） abnormality in prostate cancer, we conclude that susceptibility-weighted imaging is more sensitive and specific than conventional magnetic resonance imaging, diffusion-weighted imaging, and computed tomography in detecting prostate cancer. Furthermore, susceptibility-weighted imaging can identify prostatic calcifications similar to computed tomography, and it is much better than conventional magnetic resonance imaging and diffusion-weighted imaging.展开更多
AIM To identify a small, clinically applicable immunohistochemistry(IHC) panel that could be combined with magnetic resonance imaging(MRI)-detected extramural vascular invasion(EMVI) for assessment of prognosis concer...AIM To identify a small, clinically applicable immunohistochemistry(IHC) panel that could be combined with magnetic resonance imaging(MRI)-detected extramural vascular invasion(EMVI) for assessment of prognosis concerning the non-advanced rectal cancer patients prior to operation.METHODS About 329 patients with pathologically confirmed rectal carcinoma(RC) were screened in this research, all of whom had been examined via an MRI and were treatment-na?ve from July 2011 to July 2014. The candidate proteins that were reported to be altered by RC were examined in tissues by IHC. All chosen samples were adopted from the fundamental cores of histopathologically confirmed carcinomas during the initial surgeries.RESULTS Of the three proteins that were tested, c-MYC, PCNA and TIMP1 were detected with relatively significant expression in tumors, 35.9%, 23.7% and 58.7% respectively. The expression of the three proteins were closely connected with prognosis(P = 0.032, 0.003, 0.021). The patients could be classified into different outcome groups according to an IHC panel(P < 0.01) via these three proteins. Taking into consideration known survival covariates, especially EMVI, the IHC panel served as an independent prognostic factor. The EMVI combined with the IHC panel could categorize patients into different prognostic groups with distinction(P < 0.01).CONCLUSION These studies argue that this three-protein panel of c-MYC, PCNA, coupled with TIMP1 combined with MRIdetected EMVI could offer extra prognostic details for preoperative treatment of RC.展开更多
Magnetic resonance imaging(MRI)is considered the gold standard for the evaluation of anal fistulas.There is sufficient literature available outlining the interpretation of fistula MRI before performing surgery.However...Magnetic resonance imaging(MRI)is considered the gold standard for the evaluation of anal fistulas.There is sufficient literature available outlining the interpretation of fistula MRI before performing surgery.However,the interpretation of MRI becomes quite challenging in the postoperative period after the surgery of fistula has been undertaken.Incidentally,there are scarce data and no set guidelines regarding analysis of fistula MRI in the postoperative period.In this article,we discuss the challenges faced while interpreting the postoperative MRI,the timing of the postoperative MRI,the utility of MRI in the postoperative period for the management of anal fistulas,the importance of the active involvement and experience of the treating clinician in interpreting MRI scans,and the latest advancements in the field.展开更多
AIM: To discuss the advantages of ultra-high field (7T) for 1H and 13C magnetic resonance spectroscopy (MRS) studies of metabolism.METHODS: Measurements of brain metabolites were made at both 3 and 7T using 1H MRS. Me...AIM: To discuss the advantages of ultra-high field (7T) for 1H and 13C magnetic resonance spectroscopy (MRS) studies of metabolism.METHODS: Measurements of brain metabolites were made at both 3 and 7T using 1H MRS. Measurements of glycogen and lipids in muscle were measured using 13C and 1H MRS respectively.RESULTS: In the brain, increased signal-to-noise ratio (SNR) and dispersion allows spectral separation of the amino-acids glutamate, glutamine and γ-aminobutyric acid (GABA), without the need for sophisticated editing sequences. Improved quantification of these metabolites is demonstrated at 7T relative to 3T. SNR was 36% higher, and measurement repeatability (% coefficients of variation) was 4%, 10% and 10% at 7T, vs 8%, 29% and 21% at 3T for glutamate, glutamine and GABA respectively. Measurements at 7T were used to compare metabolite levels in the anterior cingulate cortex (ACC) and insula. Creatine and glutamate levels were found to be significantly higher in the insula compared to the ACC (P < 0.05). In muscle, the increased SNR and spectral resolution at 7T enables interleaved studies of glycogen (13C) and intra-myocellular lipid (IMCL) and extra-myocellular lipid (EMCL) (1H) following exercise and re-feeding. Glycogen levels were significantly decreased following exercise (-28% at 50% VO2 max; -58% at 75% VO2 max). Interestingly, levels of glycogen in the hamstrings followed those in the quadriceps, despite reduce exercise loading. No changes in IMCL and EMCL were found in the study.CONCLUSION: The demonstrated improvements in brain and muscle MRS measurements at 7T will increase the potential for use in investigating human metabolism and changes due to pathologies.展开更多
AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with princ...AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm3 , the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. 1H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiationtreated pancreatic tumor tissues were compared. RESULTS: Compared with 1H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the 1H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.展开更多
Gadolinium diethylenetriamine-pentaacetic bisdopamide （Gd-DTPA-2DA） was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid （DTPA） and further reaction with gadolinium chloride. In v...Gadolinium diethylenetriamine-pentaacetic bisdopamide （Gd-DTPA-2DA） was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid （DTPA） and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and pro- duced highly contrasted visualization of the brain.展开更多
Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC). In addition to serum and ...Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC). In addition to serum and histological biomarkers, there has been much recent interest in developing imaging biomarkers that can predict disease course and clinical outcomes in PSC.Magnetic resonance imaging/magnetic resonance cholangiopancreatography(MRI/MRCP) continue to play a central role in the diagnosis and follow-up of PSC patients. Magnetic resonance(MR) techniques have undergone significant advancement over the last three decades both in MR data acquisition and interpretation. The progression from a qualitative to quantitative approach in MR acquisition techniques and data interpretation, offers the opportunity for the development of objective and reproducible imaging biomarkers that can potentially be incorporated as an additional endpoint in clinical trials. This review article will discuss how the role of MR techniques have evolved over the last three decades from emerging as an alternative diagnostic tool to endoscopic retrograde cholangiopancreatography, to being instrumental in the ongoing search for imaging biomarker of disease stage, progression and prognosis in PSC.展开更多
In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic ...In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporallyencoded（SPEN） method offers an inherent applicability to r FOV imaging. In this study, a flexible r FOV imaging method is presented and the superiority of the SPEN approach in r FOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging（EPI） experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the r FOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest（ROIs） with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging.展开更多
BACKGROUND： Resovist, a superparamagnetic iron oxide, can be used to label neural stem cells （NSCs）. Magnetic resonance tracking of superparamagnetic iron oxide-labeled NSCs is a non-invasive technique to track tra...BACKGROUND： Resovist, a superparamagnetic iron oxide, can be used to label neural stem cells （NSCs）. Magnetic resonance tracking of superparamagnetic iron oxide-labeled NSCs is a non-invasive technique to track transplanted NSCs following focal cerebral ischemia. OBJECTIVE： To observe survival and migration of transplanted NSCs in a rat model of focal ischemia/repeffusion using magnetic resonance imaging （MRI）. DESIGN, TIME AND SETTING： An in vitro, in vivo, tracking study was performed at the Basic Laboratory of Harbin Medical University and the Room of MRI, Second Affiliated Hospital of Harbin Medical University, China from December 2006 to December 2009. MATERIALS： Resovist （Schering, Germany） and Achieva 1.5TMR imaging system （Philips, Amsterdam, the Netherlands） were utilized in the present study. METHODS： NSCs were harvested from brain tissues of neonatal Sprague Dawley rats and were labeled with Resovist （11.2μg/mL and 5 ×10^5 cells/mL）. A total of 15 adult, Sprague Dawley rats were randomly assigned to model （n = 9） and control （n = 6） groups. All rats were utilized to establish models of middle cerebral artery occlusion. Rats in the model group were subjected to Resovist-labeled NSCs transplantation by injection of cell suspension into both ventricles （5μL/ ventricle）. Rats in the control group were treated with an equal volume of physiological saline. MAIN OUTCOME MEASURES： Immunocytochemistry, transmission electron microscopy, and Prussian blue staining were employed to observe whether cells phagocytized iron particles. In addition, 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide assay was used to measure viability and differentiation of NSCs labeled by various concentrations of Resovist. MRI was used to trace survival and migration of Resovist-labeled NSCs. RESULTS： Following Resovist and NSCs co-incubation, Prussian blue staining revealed iron particles in cells. In addition, staining was observed in daughter cells following cell division under transmission electron microscopy. A significant difference in viability and differentiation of NSCs in vitro labeled by various Resovist concentrations （2.8-11.2 μg/mL） was not detected （P 〉 0.05）. Resovist （〉 22.4 μg/mL） decreased cell viability and differentiation （P 〈 0.05）./n vivo MRI of Resovist-labeled NSCs （11.2 μg/mL） revealed low signals. However, cells migrated towards the ischemic focus over time. CONCLUSION： Resovist, a magnetic probe, successfully labeled NSCs. MRI was successfully used to trace magnetic-labeled NSCs in vivo and allowed observation of cell survival and migration following transplantation.展开更多
Proton nuclear(^(1)H)is the observed nucleus on which most magnetic resonance imaging(MRI)applications depend.Most traditional^(1)H MRI can provide structural and functional information about organisms,while various n...Proton nuclear(^(1)H)is the observed nucleus on which most magnetic resonance imaging(MRI)applications depend.Most traditional^(1)H MRI can provide structural and functional information about organisms,while various non-proton nuclei(X-nuclei)MRI can provide more metabolic information.However,due to the relatively poor signal-to-noise ratio(SNR)of X-nuclei MRI,their applications are quite rare compared to^(1)H.Benefit from the rapid developments of MRI hardware and software technologies,X-nuclei MRI has recently attracted increasing interests in biomedical research.This review firstly introduces some current methods to improve the SNR of X-nuclei MRI.Secondly,this review describes biomedical applications of X-nuclei MRI,especially focusing on the current use of X-nuclei(^(13)C,^(17)O,^(19)F,^(23)Na and^(31)P)MRI to study related diseases in different organs,including the brain,liver,kidney,heart and bone.Finally,perspectives studies on X-nuclei imaging and its potential applications are described in biomedical research.展开更多
Chronic liver diseases(CLDs)are becoming increasingly more prevalent in modern society.The use of imaging techniques for early detection,such as magnetic resonance imaging(MRI),is crucial in reducing the impact of the...Chronic liver diseases(CLDs)are becoming increasingly more prevalent in modern society.The use of imaging techniques for early detection,such as magnetic resonance imaging(MRI),is crucial in reducing the impact of these diseases on healthcare systems.Artificial intelligence(AI)algorithms have been shown over the past decade to excel at image-based analysis tasks such as detection and segmentation.When applied to liver MRI,they have the potential to improve clinical decision making,and increase throughput by automating analyses.With Liver diseases becoming more prevalent in society,the need to implement these techniques to utilize liver MRI to its full potential,is paramount.In this review,we report on the current methods and applications of AI methods in liver MRI,with a focus on machine learning and deep learning methods.We assess four main themes of segmentation,classification,image synthesis and artefact detection,and their respective potential in liver MRI and the wider clinic.We provide a brief explanation of some of the algorithms used and explore the current challenges affecting the field.Though there are many hurdles to overcome in implementing AI methods in the clinic,we conclude that AI methods have the potential to positively aid healthcare professionals for years to come.展开更多
基金supported by National Science Foundation of China(Grant Nos.T2388102,11927811,92476204,12150014,12205296,12274395,and 12261160569)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0303205)+1 种基金Youth Innovation Promotion Association(Grant No.2023474)Chinese Academy of Sciences Magnetic Resonance Technology Alliance Research Instrument and Equipment Development/Functional Development(Grant No.2022GZL003).
文摘Zero-and ultralow-field nuclear magnetic resonance(ZULF NMR)has experienced rapid development and provides an excellent tool for diverse research fields ranging from materials science and quantum information processing to fundamental physics.The detection of ZULF NMR signals in samples with natural abundance remains a challenging endeavor,due to the limited sensitivity of NMR detectors and thermal polarization.In this work,we demonstrate a femtotesla(fT)Potassium spin-exchange relaxation-free(SERF)magnetometer designed for ZULF NMR detection.A Potassium vapor cell with high buffer gas pressure and high atomic number density is used in the magnetometer.With absorption spectroscopy and SERF effect,the key parameters of the vapor cell are characterized and applied to optimize the magnetometer sensitivity.To combine our SERF magnetometer and ZULF NMR detection,a custom-made vacuum chamber is employed to keep NMR sample close to the magnetometer cell and protect the sample from undesired heating effects.Gradiometric measurement is performed to greatly reduce the magnetic noise.With the phase calibration applied,the gradiometric measurement achieves 7-fold enhancement in magnetic-field sensitivity compared to the single channel and has a magnetic noise floor of 1.2 fT/Hz^(1/2).Our SERF magnetometer exhibits high sensitivity and is promising to realize ZULF NMR detection of samples with natural abundance.
基金Supported by Guangdong Medical Research Foundation,No.B2023272.
文摘BACKGROUND Esophageal cancer(EC)is one of the most prevalent malignant gastrointestinal tumors;accurate prediction of EC staging has high significance before treatment.AIM To explore a rational radiomic approach for predicting preoperative staging of EC based on magnetic resonance imaging(MRI).METHODS This retrospective study included 210 patients with pathologically confirmed EC,randomly divided into a primary cohort(n=147)and a validation cohort(n=63)in a ratio of 7:3.All patients underwent a preoperative MRI scan from the neck to the abdomen.High-throughput and quantitative radiomics features were extracted from T2-weighted imaging(T2WI)and gadolinium contrast-enhanced T1-weighted imaging(T1WI)-Gd images.Radiomics signatures were selected using minimal redundancy maximal relevance and the least absolute shrinkage and selection operator.Then a logistic regression model was built to predict the EC stages.The diagnostic performance of the radiomics model for discriminating between stages Ⅰ-Ⅱ and Ⅲ-Ⅳ was evaluated using the area under the curve(AUC),sensitivity(SEN),and specificity(SPE).RESULTS A total of 214 radiomics features were extracted.Following feature dimension reduction,the T1WI and T2WI sequences were retained,and 14 features from the T1WI sequence and 3 features from the T2WI sequence were selected to construct radiomics signatures.The radiomics signature combining T2WI with T1WI-Gd demonstrated superior discrimination of stages in the validation cohort(AUC:0.851;SEN:0.697;SPE:0.793),which outperformed single-sequence models(AUC:0.779,0.844;SEN:0.667,0.636;SPE:0.8,0.8).CONCLUSION MRI-based radiomics signatures could identify EC stages before treatment,which could serve as a noninvasive and quantitative approach aiding personalized treatment planning.
基金supported by the National Natural Science Foundation of China(62122064,62331021,62371410)the Natural Science Foundation of Fujian Province of China(2023J02005 and 2021J011184)+1 种基金the President Fund of Xiamen University(20720220063)the Nanqiang Outstanding Talents Program of Xiamen University.
文摘Magnetic resonance imaging(MRI)plays an important role in medical diagnosis,generating petabytes of image data annually in large hospitals.This voluminous data stream requires a significant amount of network bandwidth and extensive storage infrastructure.Additionally,local data processing demands substantial manpower and hardware investments.Data isolation across different healthcare institutions hinders crossinstitutional collaboration in clinics and research.In this work,we anticipate an innovative MRI system and its four generations that integrate emerging distributed cloud computing,6G bandwidth,edge computing,federated learning,and blockchain technology.This system is called Cloud-MRI,aiming at solving the problems of MRI data storage security,transmission speed,artificial intelligence(AI)algorithm maintenance,hardware upgrading,and collaborative work.The workflow commences with the transformation of k-space raw data into the standardized Imaging Society for Magnetic Resonance in Medicine Raw Data(ISMRMRD)format.Then,the data are uploaded to the cloud or edge nodes for fast image reconstruction,neural network training,and automatic analysis.Then,the outcomes are seamlessly transmitted to clinics or research institutes for diagnosis and other services.The Cloud-MRI system will save the raw imaging data,reduce the risk of data loss,facilitate inter-institutional medical collaboration,and finally improve diagnostic accuracy and work efficiency.
基金the Cuiying Scientific and Technological Innovation Program of Lanzhou University Second Hospital,NO.CY2021-QNB09the Science and Technology Project of Gansu Province,NO.21JR11RA122+1 种基金Department of Education of Gansu Province:Innovation Fund Project,NO.2022B-056Gansu Province Clinical Research Center for Functional and Molecular Imaging,NO.21JR7RA438.
文摘BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.
基金funding from the National Key R&D Program of China(Nos.2021YFF0501400,2021YFF0501401,and 2021YFF0501404)the Key Project of the National Natural Science Foundation of China(No.81930044).
文摘Cardiac magnetic resonance(CMR),a non-radiation based type of examination,can achieve the simultaneous comprehensive multi-parameter,multi-plane,and multi-sequence evaluation of the anatomical structure of the heart;and at the same time,determine systolic and diastolic function,and blood perfusion and tissue characteristics.Traditional late gadolinium enhancement imaging based on CMR reflects focal replacement fibrosis,in contrast to normal myocardial signal intensity,but cannot effectively identify diffuse myocardial fibrosis.T1 mapping and its derived extracellular volume fraction can be used to quantitatively analyze the extracellular space in myocardial tissue and evaluate diffuse myocardial interstitial fibrosis that is invisible to the naked eye.Diffusion tensor imaging reveals the direction of cardiomyocyte aggregates by quantifying the anisotropy of water molecule diffusion,and can be applied to evaluate the integrity of myocardial tissue and arrangement structure of myocardial microstructural characteristics.On the basis of the micro-motion of myocardial tissue,feature tracking analysis decomposes myocardial deformation into three dimensions of micro-mechanical changes,and can identify early systolic and diastolic dysfunction before heart enlargement or ejection fraction reduction.This Commentary discusses current research advances in these new techniques,as well as their clinical application prospects and limitations for non-ischemic cardiomyopathies.
文摘BACKGROUND Magnetic resonance imaging(MRI)combined with serum endothelin and galactagoglobin-3(Gal-3)can improve the clinical diagnosis of diabetes mellitus complicated with cerebral infarction.AIM To analyze the clinical value of MRI combined with serum endolipin and Gal-3 for the diagnosis of cerebral infarction in the elderly with diabetes mellitus.METHODS One hundred and fifty patients with acute cerebral infarction hospitalized between January 2021 and December 2023 were divided into two groups according to comorbid diabetes mellitus,including 62 and 88 cases in the diabetic and nondiabetic cerebral infarction groups.Serum samples were collected to detect the expression of serum endolipoxins,and Gal-3,and cranial MRI was performed at admission.Differences between the two groups were compared to analyze the diagnostic value of these parameters.RESULTS Serum endolipin and Gal-3 expression were higher in the diabetic cerebral infarction group(P<0.05).The arterial wall area,vessel area,normalized wall index,and lumen stenosis rate were higher in the diabetic cerebral infarction group,while the rate of arterial lumen moderate and severe stenosis was 48.39% higher(36.36%,P<0.05).The percentage of large(29.03%)and multiple infarcts(33.87%)in the diabetic cerebral infarction group was higher(13.64% and 20.45%),and the incidence rate of lacunar infarcts was lower(37.10%vs 65.91%)(P<0.05).The total incidence of arterial plaque in patients in the diabetic cerebral infarction group was 96.77% higher(69.32%),while the incidence of necrotic lipid core plaque was 58.06%higher(26.14%)(P<0.05).Receiver operating characteristic curve analysis was performed to assess the diagnosis utility of these techniques.MRI in combination with serum endoglin and Gal-3 had the highest area under the curve,the Yoden index,sensitivity and specificity(P<0.05).CONCLUSION The expression of serum endolipin and Gal-3 in elderly patients with diabetes mellitus with cerebral infarction showed an elevated trend,and the degree of luminal stenosis was severe.MRI predominantly revealed large and multiple infarct foci.This combined index examination can improve the clinical diagnosis of diabetes mellitus combined with cerebral infarction.
基金National Natural Science Foundation of China,Grant/Award Numbers:82071280,82172021。
文摘The field of radiology is currently undergoing revolutionary changes owing to the increasing application of artificial intelligence(AI).This scoping review identifies and summarizes the technical methods and clinical applications of AI applied to magnetic resonance imaging of cerebrovascular diseases(CVDs).Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews was adopted and articles listed in PubMed and Cochrane databases from January 1,2018 to December 31,2023,were assessed.In total,67 articles met the eligibility criteria.We obtained a general overview of the field,including lesion types,sample sizes,data sources,and databases and found that nearly half of the studies used multisequence magnetic resonance as the input.Both classical machine learning and deep learning were widely used.The evaluation metrics varied according to the five main algorithm tasks of classification,detection,segmentation,estimation,and generation.Cross-validation was primarily used with only one third of the included studies using external validation.We also illustrate the key questions of the CVD research studies and grade the clinical utility of their AI solutions.Although most attention is devoted to improving the performance of AI models,this scoping review provides information on the availability of algorithms,reli-ability of external validations,and consistency of evaluation metrics and may facilitate improved clinical applicability and acceptance.
基金supported by Shenzhen Municipal Collaborative Innovation Technology Program-International Science and Technology(S&T)Cooperation Project(No.GJHZ20220913142609017)Shenzhen Science and Technology Innovation Commission Key Technical Project(No.JSGG20210713091539014)+1 种基金Ling Chuang Research Project of China National Nuclear Corporationthe“Fourteen Five-Year Plan”Basic Technological Research Project(No.JSZL2022XXXX001)。
文摘Ion cyclotron resonance heating(ICRH)stands out as a widely utilized and cost-effective auxiliary method for plasma heating,bearing significant importance in achieving high-performance discharges in p-^(11)B plasmas.In light of the specific context of p-^(11)B plasma in the EHL-2 device,we conducted a comprehensive scan of the fundamental physical parameters of the antenna using the full-wave simulation program TORIC.Our preliminary result indicated that for p-^(11)B plasma,optimal ion heating parameters include a frequency of 40 MHz,with a high toroidal mode number like N_(?)=28 to heat the majority H ions.In addition,we discussed the impact of concentration of minority ion species on ion cyclotron resonance heating when^(11)B serves as the heavy minority species.The significant difference in charge-to-mass ratio between boron and hydrogen ions results in a considerable distance between the hybrid resonance layer and the tow inverted cyclotron resonance layer,necessitating a quite low boron ion concentration to achieve effective minority heating.We also considered another method of direct heating of hydrogen ions in the presence of boron ion minority.It is found that at appropriate boron ion concentrations(X(^(11)B)~17%),the position of the hybrid resonance layer approaches that of the hydrogen ion cyclotron resonance layer,thereby altering the polarization at this position and significantly enhancing hydrogen ion fundamental absorption.
基金supported by the Science and Technology Program of Guangzhou,No.2006Z12E0119Guangzhou Science and Technology Key Project,No.122732961131543
文摘A total of 29 patients were treated within 48 hours after acute subcortical cerebral infarction with Xuesaitong or Xuesaitong plus human urinary kallidinogenase for 14 days. Neurological deficits, activity of daily living, and evaluations of distal upper limb motor functions at the 6-month follow-up showed that patients treated with Xuesaitong plus human urinary kallidinogenase recovered better than with Xuesaitong alone. In addition, functional MRI revealed that activation sites were primarily at the ipsilesional side of injury in all patients. Human urinary kallidinogenase induced hyperactivation of the ipsilesional primary sensorimotor cortex, premotor cortex, supplementary motor area, and contralesional posterior parietal cortex. Results showed that human urinary kallidinogenase improved symptoms of neurological deficiency by enhancing remodeling of long-term cortical motor function in patients with acute cerebral infarction.
文摘Prostate cancer and prostatic calcifications have a high incidence in elderly men. We aimed to investigate the diagnostic capabilities of susceptibility-weighted imaging in detecting prostate cancer and prostatic calcifications. A total number of 156 men, including 34 with prostate cancer and 122 with benign prostate were enrolled in this study. Computed tomography, conventional magnetic resonance imaging, diffusion-weighted imaging, and susceptibility-weighted imaging were performed on all the patients. One hundred and twelve prostatic calcifications were detected in 87 patients. The sensitivities and specificities of the conventional magnetic resonance imaging, apparent diffusion coefficient, and susceptibility-filtered phase images in detecting prostate cancer and prostatic calcifications were calculated. McNemar＇s Chi-square test was used to compare the differences in sensitivities and specificities between the techniques. The results showed that the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic cancer were greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient （P 〈 0.05）. In addition, the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic calcifications were comparable to that of computed tomography and greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient （P 〈 0.05）. Given the high incidence of susceptibility-weighted imaging （SWl） abnormality in prostate cancer, we conclude that susceptibility-weighted imaging is more sensitive and specific than conventional magnetic resonance imaging, diffusion-weighted imaging, and computed tomography in detecting prostate cancer. Furthermore, susceptibility-weighted imaging can identify prostatic calcifications similar to computed tomography, and it is much better than conventional magnetic resonance imaging and diffusion-weighted imaging.
文摘AIM To identify a small, clinically applicable immunohistochemistry(IHC) panel that could be combined with magnetic resonance imaging(MRI)-detected extramural vascular invasion(EMVI) for assessment of prognosis concerning the non-advanced rectal cancer patients prior to operation.METHODS About 329 patients with pathologically confirmed rectal carcinoma(RC) were screened in this research, all of whom had been examined via an MRI and were treatment-na?ve from July 2011 to July 2014. The candidate proteins that were reported to be altered by RC were examined in tissues by IHC. All chosen samples were adopted from the fundamental cores of histopathologically confirmed carcinomas during the initial surgeries.RESULTS Of the three proteins that were tested, c-MYC, PCNA and TIMP1 were detected with relatively significant expression in tumors, 35.9%, 23.7% and 58.7% respectively. The expression of the three proteins were closely connected with prognosis(P = 0.032, 0.003, 0.021). The patients could be classified into different outcome groups according to an IHC panel(P < 0.01) via these three proteins. Taking into consideration known survival covariates, especially EMVI, the IHC panel served as an independent prognostic factor. The EMVI combined with the IHC panel could categorize patients into different prognostic groups with distinction(P < 0.01).CONCLUSION These studies argue that this three-protein panel of c-MYC, PCNA, coupled with TIMP1 combined with MRIdetected EMVI could offer extra prognostic details for preoperative treatment of RC.
文摘Magnetic resonance imaging(MRI)is considered the gold standard for the evaluation of anal fistulas.There is sufficient literature available outlining the interpretation of fistula MRI before performing surgery.However,the interpretation of MRI becomes quite challenging in the postoperative period after the surgery of fistula has been undertaken.Incidentally,there are scarce data and no set guidelines regarding analysis of fistula MRI in the postoperative period.In this article,we discuss the challenges faced while interpreting the postoperative MRI,the timing of the postoperative MRI,the utility of MRI in the postoperative period for the management of anal fistulas,the importance of the active involvement and experience of the treating clinician in interpreting MRI scans,and the latest advancements in the field.
基金Supported by The Haldane-Spearman Consortium for PhD funding for Dr. Gunner F, Swecarb AB for provision of the carbo-hydrate drink，and Pfizer for funding the 1H Repeatability work Dr.Stephenson M was supported by the University of Notting-ham’s Mansfield Fellowship scheme+2 种基金7T work was supported by grant G9900259 from the Medical Research CouncilPfizer and grant G0901321 from the Medical Research CouncilThe 7 T MR Scanner in Nottingham, was funded by a Joint Infrastructure Fund Grant from the Wellcome Trust UK
文摘AIM: To discuss the advantages of ultra-high field (7T) for 1H and 13C magnetic resonance spectroscopy (MRS) studies of metabolism.METHODS: Measurements of brain metabolites were made at both 3 and 7T using 1H MRS. Measurements of glycogen and lipids in muscle were measured using 13C and 1H MRS respectively.RESULTS: In the brain, increased signal-to-noise ratio (SNR) and dispersion allows spectral separation of the amino-acids glutamate, glutamine and γ-aminobutyric acid (GABA), without the need for sophisticated editing sequences. Improved quantification of these metabolites is demonstrated at 7T relative to 3T. SNR was 36% higher, and measurement repeatability (% coefficients of variation) was 4%, 10% and 10% at 7T, vs 8%, 29% and 21% at 3T for glutamate, glutamine and GABA respectively. Measurements at 7T were used to compare metabolite levels in the anterior cingulate cortex (ACC) and insula. Creatine and glutamate levels were found to be significantly higher in the insula compared to the ACC (P < 0.05). In muscle, the increased SNR and spectral resolution at 7T enables interleaved studies of glycogen (13C) and intra-myocellular lipid (IMCL) and extra-myocellular lipid (EMCL) (1H) following exercise and re-feeding. Glycogen levels were significantly decreased following exercise (-28% at 50% VO2 max; -58% at 75% VO2 max). Interestingly, levels of glycogen in the hamstrings followed those in the quadriceps, despite reduce exercise loading. No changes in IMCL and EMCL were found in the study.CONCLUSION: The demonstrated improvements in brain and muscle MRS measurements at 7T will increase the potential for use in investigating human metabolism and changes due to pathologies.
基金Supported by The Medical Imageology Special Purpose Foundation of Cancer Hospital/Cancer Institute Fudan University, No.YX200802
文摘AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm3 , the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. 1H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiationtreated pancreatic tumor tissues were compared. RESULTS: Compared with 1H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the 1H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.
基金Project supported by National Natural Science Foundation of China (51173140)Key Natural Science Foundation of Hubei Province (2009CDA052)Wuhan Scientific and Technological Research and Development Program, Hubei Province (201060623274)
文摘Gadolinium diethylenetriamine-pentaacetic bisdopamide （Gd-DTPA-2DA） was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid （DTPA） and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and pro- duced highly contrasted visualization of the brain.
基金the National Institute of Health Research(NIHR)Biomedical Research Centre,based at Oxford University Hospitals NHS Foundation TrustOxfordshire Health Service Research Committee(OHSRC)as part of Oxford Hospitals Charity,Oxford
文摘Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC). In addition to serum and histological biomarkers, there has been much recent interest in developing imaging biomarkers that can predict disease course and clinical outcomes in PSC.Magnetic resonance imaging/magnetic resonance cholangiopancreatography(MRI/MRCP) continue to play a central role in the diagnosis and follow-up of PSC patients. Magnetic resonance(MR) techniques have undergone significant advancement over the last three decades both in MR data acquisition and interpretation. The progression from a qualitative to quantitative approach in MR acquisition techniques and data interpretation, offers the opportunity for the development of objective and reproducible imaging biomarkers that can potentially be incorporated as an additional endpoint in clinical trials. This review article will discuss how the role of MR techniques have evolved over the last three decades from emerging as an alternative diagnostic tool to endoscopic retrograde cholangiopancreatography, to being instrumental in the ongoing search for imaging biomarker of disease stage, progression and prognosis in PSC.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474236,81171331,and U1232212)
文摘In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporallyencoded（SPEN） method offers an inherent applicability to r FOV imaging. In this study, a flexible r FOV imaging method is presented and the superiority of the SPEN approach in r FOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging（EPI） experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the r FOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest（ROIs） with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging.
基金the Scientific Research Program of Health Department in Heilongjiang Province,No.2007-331the Doctoral Foundation of the Second Affiliated Hospital of Harbin Medical University,No.BS2006-29
文摘BACKGROUND： Resovist, a superparamagnetic iron oxide, can be used to label neural stem cells （NSCs）. Magnetic resonance tracking of superparamagnetic iron oxide-labeled NSCs is a non-invasive technique to track transplanted NSCs following focal cerebral ischemia. OBJECTIVE： To observe survival and migration of transplanted NSCs in a rat model of focal ischemia/repeffusion using magnetic resonance imaging （MRI）. DESIGN, TIME AND SETTING： An in vitro, in vivo, tracking study was performed at the Basic Laboratory of Harbin Medical University and the Room of MRI, Second Affiliated Hospital of Harbin Medical University, China from December 2006 to December 2009. MATERIALS： Resovist （Schering, Germany） and Achieva 1.5TMR imaging system （Philips, Amsterdam, the Netherlands） were utilized in the present study. METHODS： NSCs were harvested from brain tissues of neonatal Sprague Dawley rats and were labeled with Resovist （11.2μg/mL and 5 ×10^5 cells/mL）. A total of 15 adult, Sprague Dawley rats were randomly assigned to model （n = 9） and control （n = 6） groups. All rats were utilized to establish models of middle cerebral artery occlusion. Rats in the model group were subjected to Resovist-labeled NSCs transplantation by injection of cell suspension into both ventricles （5μL/ ventricle）. Rats in the control group were treated with an equal volume of physiological saline. MAIN OUTCOME MEASURES： Immunocytochemistry, transmission electron microscopy, and Prussian blue staining were employed to observe whether cells phagocytized iron particles. In addition, 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide assay was used to measure viability and differentiation of NSCs labeled by various concentrations of Resovist. MRI was used to trace survival and migration of Resovist-labeled NSCs. RESULTS： Following Resovist and NSCs co-incubation, Prussian blue staining revealed iron particles in cells. In addition, staining was observed in daughter cells following cell division under transmission electron microscopy. A significant difference in viability and differentiation of NSCs in vitro labeled by various Resovist concentrations （2.8-11.2 μg/mL） was not detected （P 〉 0.05）. Resovist （〉 22.4 μg/mL） decreased cell viability and differentiation （P 〈 0.05）./n vivo MRI of Resovist-labeled NSCs （11.2 μg/mL） revealed low signals. However, cells migrated towards the ischemic focus over time. CONCLUSION： Resovist, a magnetic probe, successfully labeled NSCs. MRI was successfully used to trace magnetic-labeled NSCs in vivo and allowed observation of cell survival and migration following transplantation.
基金supported by Chinese Academy of Sciences MRI Technology Alliance under Grant 2020GZ1003.
文摘Proton nuclear(^(1)H)is the observed nucleus on which most magnetic resonance imaging(MRI)applications depend.Most traditional^(1)H MRI can provide structural and functional information about organisms,while various non-proton nuclei(X-nuclei)MRI can provide more metabolic information.However,due to the relatively poor signal-to-noise ratio(SNR)of X-nuclei MRI,their applications are quite rare compared to^(1)H.Benefit from the rapid developments of MRI hardware and software technologies,X-nuclei MRI has recently attracted increasing interests in biomedical research.This review firstly introduces some current methods to improve the SNR of X-nuclei MRI.Secondly,this review describes biomedical applications of X-nuclei MRI,especially focusing on the current use of X-nuclei(^(13)C,^(17)O,^(19)F,^(23)Na and^(31)P)MRI to study related diseases in different organs,including the brain,liver,kidney,heart and bone.Finally,perspectives studies on X-nuclei imaging and its potential applications are described in biomedical research.
基金by the Engineering and Physical Sciences Research Council and Medical Research Council,No.EP/L016052/1.
文摘Chronic liver diseases(CLDs)are becoming increasingly more prevalent in modern society.The use of imaging techniques for early detection,such as magnetic resonance imaging(MRI),is crucial in reducing the impact of these diseases on healthcare systems.Artificial intelligence(AI)algorithms have been shown over the past decade to excel at image-based analysis tasks such as detection and segmentation.When applied to liver MRI,they have the potential to improve clinical decision making,and increase throughput by automating analyses.With Liver diseases becoming more prevalent in society,the need to implement these techniques to utilize liver MRI to its full potential,is paramount.In this review,we report on the current methods and applications of AI methods in liver MRI,with a focus on machine learning and deep learning methods.We assess four main themes of segmentation,classification,image synthesis and artefact detection,and their respective potential in liver MRI and the wider clinic.We provide a brief explanation of some of the algorithms used and explore the current challenges affecting the field.Though there are many hurdles to overcome in implementing AI methods in the clinic,we conclude that AI methods have the potential to positively aid healthcare professionals for years to come.
