BACKGROUND The study on predicting the differentiation grade of colorectal cancer(CRC)based on magnetic resonance imaging(MRI)has not been reported yet.Developing a non-invasive model to predict the differentiation gr...BACKGROUND The study on predicting the differentiation grade of colorectal cancer(CRC)based on magnetic resonance imaging(MRI)has not been reported yet.Developing a non-invasive model to predict the differentiation grade of CRC is of great value.AIM To develop and validate machine learning-based models for predicting the differ-entiation grade of CRC based on T2-weighted images(T2WI).METHODS We retrospectively collected the preoperative imaging and clinical data of 315 patients with CRC who underwent surgery from March 2018 to July 2023.Patients were randomly assigned to a training cohort(n=220)or a validation cohort(n=95)at a 7:3 ratio.Lesions were delineated layer by layer on high-resolution T2WI.Least absolute shrinkage and selection operator regression was applied to screen for radiomic features.Radiomics and clinical models were constructed using the multilayer perceptron(MLP)algorithm.These radiomic features and clinically relevant variables(selected based on a significance level of P<0.05 in the training set)were used to construct radiomics-clinical models.The performance of the three models(clinical,radiomic,and radiomic-clinical model)were evaluated using the area under the curve(AUC),calibration curve and decision curve analysis(DCA).RESULTS After feature selection,eight radiomic features were retained from the initial 1781 features to construct the radiomic model.Eight different classifiers,including logistic regression,support vector machine,k-nearest neighbours,random forest,extreme trees,extreme gradient boosting,light gradient boosting machine,and MLP,were used to construct the model,with MLP demonstrating the best diagnostic performance.The AUC of the radiomic-clinical model was 0.862(95%CI:0.796-0.927)in the training cohort and 0.761(95%CI:0.635-0.887)in the validation cohort.The AUC for the radiomic model was 0.796(95%CI:0.723-0.869)in the training cohort and 0.735(95%CI:0.604-0.866)in the validation cohort.The clinical model achieved an AUC of 0.751(95%CI:0.661-0.842)in the training cohort and 0.676(95%CI:0.525-0.827)in the validation cohort.All three models demonstrated good accuracy.In the training cohort,the AUC of the radiomic-clinical model was significantly greater than that of the clinical model(P=0.005)and the radiomic model(P=0.016).DCA confirmed the clinical practicality of incorporating radiomic features into the diagnostic process.CONCLUSION In this study,we successfully developed and validated a T2WI-based machine learning model as an auxiliary tool for the preoperative differentiation between well/moderately and poorly differentiated CRC.This novel approach may assist clinicians in personalizing treatment strategies for patients and improving treatment efficacy.展开更多
Objective:To achieve precision medicine,the use of imaging methods to help the clinical detection of cerebral infarction is conducive to the clinical development of a treatment plan and increase of the cure rate and i...Objective:To achieve precision medicine,the use of imaging methods to help the clinical detection of cerebral infarction is conducive to the clinical development of a treatment plan and increase of the cure rate and improvement of the prognosis of patients.Methods:In this work,T2-weighted imaging(T2WI),diffusion-weighted imaging(DWI),susceptibility-weighted imaging(SWI),and diffusion tensor imaging(DTI)examinations were performed on 34 patients with clinically diagnosed cerebral infarction to measure the difference in signal intensity between the lesion and its mirror area and make a comparative analysis by means of the Student-Newman-Keuls method.Results:The detection rate of T2WI was 79%(27/34),the detection rate of DWI was 97%(33/34),the detection rate of SWI was 88%(30/34),and the detection rate of DTI was 94%(32/34).Conclusion:The imaging performance was in the order DWI>DTI>SWI>T2WI for the diagnosis of cerebral infarction,and combined imaging is better than single imaging.展开更多
The contrast agent concentration, the time of repetition (TR) and magnetic field strength are significant parameters that influence for the accurate signal intensity (SI) in quantitative Magnetic Resonance Imaging (MR...The contrast agent concentration, the time of repetition (TR) and magnetic field strength are significant parameters that influence for the accurate signal intensity (SI) in quantitative Magnetic Resonance Imaging (MRI). Therefore, this study was conducted to investigate and refine the dependence and the optimal effect of Time of Repetition (TR) on the relationship between signal intensity and Gd-DTPA (Gadolinium-diethylene-triaminepenta-acetic acid) concentration, after applying two-dimensional (2D) Spin Echo (SE) pulse sequence under low-field MRI. In addition to that, the optimal concentration of Gd-DTPA at given sequence parameters at low-field MRI was also evaluated. A water-filled phantom was constructed for a range of Gd-DTPA concentrations (0 - 6 mmol/L) and the mean signal intensities (SIs) were assessed in the defined region of interest on T1-weighted images with different TR values (40 - 2000 ms). The generated signal-concentration curves for Gd-DTPA revealed that increasing TR was associated with the increase of the overall SIs and the maximum relationship between SI to concentration. Moreover, the required Gd-DTPA concentration to produce the maximum SI was associated to decrease with the increase of TR. In addition to this, the application of beyond 100 ms TR values in this study with relatively higher concentrations (beyond 1 - 2 mmol/L) has resulted predominantly non-linear patterns in the signal-concentration curves and it appears the saturation or decay of the SIs due to T2 effect. From these results, it can be suggested that the selection of relatively lower Gd-DTPA concentration ( mmol/L) with less than 800 ms (<800 ms) TR values can produce a better linear relationship between the concertation and SIs in T1-weighted SE low field contrast-enhanced MRI. Furthermore, this study also outlined the significance and necessity of the optimization of TR in SE sequence in low field MRI prior to a particular examination.展开更多
According to clinical statistics,the mortality of patients with early brainstem hemorrhage is high.In this study,we established rat models of brainstem hemorrhage by injecting type Ⅶ collagenase into the right basote...According to clinical statistics,the mortality of patients with early brainstem hemorrhage is high.In this study,we established rat models of brainstem hemorrhage by injecting type Ⅶ collagenase into the right basotegmental pontine and investigated the pathological changes of early brainstem hemorrhage using multi-sequence magnetic resonance imaging and histopathological methods.We found that brainstem hematoma gradually formed in the injured rats over the first 3 days and then reduced after 7 days.The edema that occurred was mainly of the vasogenic type.No complete myelin sheath structure was found around the focus of the brainstem hemorrhage.The integrity and continuity of nerve fibers gradually deteriorated over the first 7 days.Neuronal degeneration was mild in the first 3 days and then obviously aggravated on the 7^(th)day.Inflammatory cytokines,interleukin-1β,and tumor necrosis factorαappeared on the 1st day after intracerebral hemorrhage,reached peak levels on the 3^(rd)day,and decreased from the 7^(th)day.Our findings show the characteristics of the progression of early brainstem hemorrhage.展开更多
Patients with type 2 diabetes mellitus(T2 DM) often have cognitive impairment and structural brain abnormalities.The magnetic resonance imaging(MRI)-based brain atrophy and lesion index can be used to evaluate common ...Patients with type 2 diabetes mellitus(T2 DM) often have cognitive impairment and structural brain abnormalities.The magnetic resonance imaging(MRI)-based brain atrophy and lesion index can be used to evaluate common brain changes and their correlation with cognitive function,and can therefore also be used to reflect whole-brain structural changes related to T2 DM.A total of 136 participants(64 men and 72 women,aged 55–86 years) were recruited for our study between January 2014 and December 2016.All participants underwent MRI and Mini-Mental State Examination assessment(including 42 healthy control,38 T2 DM without cognitive impairment,26 with cognitive impairment but without T2 DM,and 30 T2 DM with cognitive impairment participants).The total and sub-category brain atrophy and lesion index scores in patients with T2 DM with cognitive impairment were higher than those in healthy controls.Differences in the brain atrophy and lesion index of gray matter lesions and subcortical dilated perivascular spaces were found between non-T2 DM patients with cognitive impairment and patients with T2 DM and cognitive impairment.After adjusting for age,the brain atrophy and lesion index retained its capacity to identify patients with T2 DM with cognitive impairment.These findings suggest that the brain atrophy and lesion index,based on T1-weighted and T2-weighted imaging,is of clinical value for identifying patients with T2 DM and cognitive impairment.Gray matter lesions and subcortical dilated perivascular spaces may be potential diagnostic markers of T2 DM that is complicated by cognitive impairment.This study was approved by the Medical Ethics Committee of University of South China(approval No.USC20131109003) on November 9,2013,and was retrospectively registered with the Chinese Clinical Trial Registry(registration No.Chi CTR1900024150) on June 27,2019.展开更多
Brain radiomics can reflect the characteristics of brain pathophysiology.However,the value of T1-weighted images,quantitative susceptibility mapping,and R2*mapping in the diagnosis of Parkinson’s disease(PD)was under...Brain radiomics can reflect the characteristics of brain pathophysiology.However,the value of T1-weighted images,quantitative susceptibility mapping,and R2*mapping in the diagnosis of Parkinson’s disease(PD)was underestimated in previous studies.In this prospective study to establish a model for PD diagnosis based on brain imaging information,we collected high-resolution T1-weighted images,R2*mapping,and quantitative susceptibility imaging data from 171 patients with PD and 179 healthy controls recruited from August 2014 to August 2019.According to the inclusion time,123 PD patients and 121 healthy controls were assigned to train the diagnostic model,while the remaining 106 subjects were assigned to the external validation dataset.We extracted 1408 radiomics features,and then used data-driven feature selection to identify informative features that were significant for discriminating patients with PD from normal controls on the training dataset.The informative features so identified were then used to construct a diagnostic model for PD.The constructed model contained 36 informative radiomics features,mainly representing abnormal subcortical iron distribution(especially in the substantia nigra),structural disorganization(e.g.,in the inferior temporal,paracentral,precuneus,insula,and precentral gyri),and texture misalignment in the subcortical nuclei(e.g.,caudate,globus pallidus,and thalamus).The predictive accuracy of the established model was 81.1±8.0%in the training dataset.On the external validation dataset,the established model showed predictive accuracy of 78.5±2.1%.In the tests of identifying early and drug-naïve PD patients from healthy controls,the accuracies of the model constructed on the same 36 informative features were 80.3±7.1%and 79.1±6.5%,respectively,while the accuracies were 80.4±6.3%and 82.9±5.8%for diagnosing middle-to-late PD and those receiving drug management,respectively.The accuracies for predicting tremor-dominant and non-tremor-dominant PD were 79.8±6.9%and 79.1±6.5%,respectively.In conclusion,the multiple-tissue-specific brain radiomics model constructed from magnetic resonance imaging has the ability to discriminate PD and exhibits the advantages for improving PD diagnosis.展开更多
A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain o...A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain order fractional Fourier domain and transformed by 4-WFRFT to compose the hybrid carrier signals. In the time domain CDMA technique is adopted for multiple accesses and time diversity gain. Compared to orthogonal frequency division multiplexing (OFDM) system, in which Fourier transform is adopted, the signal energy in HC system is distributed on the time-frequency plane more evenly and symmetrically. Thus, when there is a deep fading notch or single-frequency interference in the channel, the proposed method can split the interference to a broader range in order to reduce the influence, resulting in the better system performance. Moreover, the performances of the proposed system, such as peak-to-average power rate (PAPR) and security are also discussed in the paper.展开更多
A new kind of weight-Ar^λ3 (λ1, λ2, Ω)-weight is used to prove the local and global integral inequalities for conjugate A-harmonic tensors, which can be regarded as generalizations of the classical results. Some...A new kind of weight-Ar^λ3 (λ1, λ2, Ω)-weight is used to prove the local and global integral inequalities for conjugate A-harmonic tensors, which can be regarded as generalizations of the classical results. Some applications of the above results to quasiregular mappings are given.展开更多
We report on the case of middle-aged right-handed woman with central pontine myelinolysis (CPM) revealed by high resolution structural T2-weighted FLAIR MRI imaging. There was a general flattening of Wechsler Adult In...We report on the case of middle-aged right-handed woman with central pontine myelinolysis (CPM) revealed by high resolution structural T2-weighted FLAIR MRI imaging. There was a general flattening of Wechsler Adult Intelligence Scale—Fourth Edition subtest scores which were 1 standard deviation below expected values. In contrast Wechsler Memory Scale—Fourth Edition visual and auditory memory scores remained within the normal range. Verbal working memory appeared mildly impaired while nonverbal working memory was not. Scores on the Advanced Clinical Solution’s Social Perception battery were all in the normal range as were academic skills measured by the Wide Range Achievement Test—Fourth Edition. Performance was impaired on the Delis-Kaplan Executive Function System’s counterpart of the Trail-Making Test: Part B. Similarly, on the Draw-A-Person Test there was a discrepancy in that our patient’s standard score was 76 compared to her estimated premorbid FSIQ in the average range. She also displayed bilateral motor coordination slowing on the Finger Tapping task collectively suggesting damage to pontine motor tracts. The Minnesota Multiphasic Personality Inventory—Second Edition—Restructured Form profile was consistent with a diagnosis of severe anxiety and depression perhaps due to damage to serotoninergic neural tracts originating within the central pons. Finally, the patient displayed severe sleep disturbances and other signs of reticular activating formation injury. CPM may constitute a unique means of studying reversible subcortical lesions in the central pons in otherwise healthy subjects with benign illness. To our knowledge this is among the first patients with CPM without the usual risk factors for the disorder and who was otherwise healthy. Knowledge of the etiology and neuropsychology of such patients might aid in understanding the interaction of the fronto-ponto-cerebellar tracts in executive functions and motor programming.展开更多
Background Differential diagnosis of intracranial hemorrhage and calcification is a common problem encountered in clinical imaging diagnosis. The purpose of this study was to investigate the feasibility of T2* measur...Background Differential diagnosis of intracranial hemorrhage and calcification is a common problem encountered in clinical imaging diagnosis. The purpose of this study was to investigate the feasibility of T2* measurement on gradient echo (GRE) T2*-weighted imaging (T2*WI) in differential diagnosis of intracranial hemorrhage and calcification. Methods Thirty-eight hemorrhagic foci in 18 patients and 11 calcification foci in seven patients were included in this study. The diagnosis of hemorrhage and calcification was confirmed in all cases with enhanced T2* weighted angiography (ESWAN) magnetic resonance imaging (MRI) and CT respectively. The significance for the difference of T2* value between the central and peripheral areas of hemorrhage and calcification lesions was tested with univariate analysis of variance, Results The detection rate of GRE T2*WI on intracranial hemorrhage was 1.9-fold higher than that of CT, especially for the hemorrhage in the brainstem and cerebellum. However, GRE T2*WI was far less sensitive to calcification than CT. There was a significant difference in the T2* value between the central area of hemorrhage and calcification (P 〈0.001), though no difference in the T2* value was obtained between the peripheral area of hemorrhage and calcification (P 〉0.05). Conclusions Quantitative measurement of T2* value on GRE T2*WI with a single MRI examination provides a fast, convenient, and effective means in differential diagnosis between intracranial hemorrhage and calcification, which may thus reduce the medical cost and save precious time for clinical management.展开更多
Polyethylene glycol modified(PEGylated) NaGdF4(PEG-NaGdF4) nanoparticles as a novel T1-weighted magnetic resonance imaging(MRI) contrast agent was successfully constructed by a one-pot hydrothermal synthesis method. B...Polyethylene glycol modified(PEGylated) NaGdF4(PEG-NaGdF4) nanoparticles as a novel T1-weighted magnetic resonance imaging(MRI) contrast agent was successfully constructed by a one-pot hydrothermal synthesis method. Because of the functionalization of PEG, the nanoprobes had excellent dispersity, excellent stability and high biocompatibility. More importantly, the as-prepared PEG-NaGdF4 nanoprobes revealed the high longitudinal relaxivity value and prominent -weighted MRI contrast performance, which was superior to the commercial MRI contrast agents. With the facile synthesis, excellent dispersity, outstanding stability, remarkable contrast performance and high biocompatibility, the PEGylated NaGdF4 nanoparticles brought more opportunities to the new generation of nanoparticulate-based T1-weighted MRI contrast agents in clinic.展开更多
Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has...Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has become the mainstream method for monitoring glycogen in the body.However,the equipment of special hard-ware to standard clinical magnetic resonance imaging(MRI)scanners limits its clinical applications.Herein,we utilized endogenous glycogen as a T_(2)-based relaxation contrast agent for imaging glycogen metabolism in the liver in vivo.The in vitro results demonstrated that the transverse relaxation rate of glycogen strongly correlates with the concentration,pH,and field strength.Based on the Swift-Connick theory,we characterized the exchange property of glycogen and measured the exchange rate of glycogen as 31,847 Hz at 37°C.Besides,the viscosity and echo spacing showed no apparent effect on the transverse relaxation rate.This unique feature enables vi-sualization of glycogen signaling in vivo through T_(2)-weighted MRI.Two hours-post intraperitoneal injection of glucagon,a clinical drug to promote glycogenolysis and gluconeogenesis,the signal intensity of the mice’s liver increased by 1.8 times from the T_(2)-weighted imaging experiment due to the decomposition of glycogen.This study provides a convenient imaging strategy to non-invasively investigate glycogen metabolism in the liver,which may find clinical applications in metabolic diseases.展开更多
A certain weighted Herz-type Hardy space is introduced and its atom-decomposition theory is established. As applications of this theory, a boundedness theorem of sublinear operators and an interpolation theorem of lin...A certain weighted Herz-type Hardy space is introduced and its atom-decomposition theory is established. As applications of this theory, a boundedness theorem of sublinear operators and an interpolation theorem of linear operators on these spaces are given.展开更多
Mn-TCPP-CSn(n=6,1 1,20) as a type of potential magnetic resonance imaging(MRI) contrast agents were synthesized via manganese(Ⅱ) meso-tetra(4-carboxyphenyl) porphyrin(Mn-TCPP) modified with chitosan oligosa...Mn-TCPP-CSn(n=6,1 1,20) as a type of potential magnetic resonance imaging(MRI) contrast agents were synthesized via manganese(Ⅱ) meso-tetra(4-carboxyphenyl) porphyrin(Mn-TCPP) modified with chitosan oligosaccharides(CSn).Experimental data of infared(IR),UV-Vis,MS,inductively coupled plasma-atomic emission spectrometer(ICP-AES) and size exclusion chromatography evidenced the formation of Mn-TCPP-CSn-The stability results show that Mn-TCPP-CSn in aqueous solution was stable enough to prevent Mn(Ⅱ) ions from leaking.The magnetic properties in vitro indicate that Mn-TCPP-CS20 possesses higher longitudinal relaxivity(r1=10.38 L·mmol^-1·s^-1) in aqueous solution than unmodified porphyrin Mn-TCPPNa4[manganese(Ⅱ) meso-tetra(4-carboxyphenyl) porphyrin,tetrasodium salt](r1=5.10 L·mmol^-1·s^-1) and the commercial contrast agent Gd-DTPA(r1=4.05 L·mmol^-1·s^-1).The preliminary T1-weighted flash image studies in vitro show that the contrast and the imaging signal of Mn-TCPP-CSn were superior to those of Mn-TCPPNa4 and Gd-DTPA under the same conditions.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay shows that Mn-TCPP-CSn has a good biocompatibility.In addition,the thermodynamical parameters(ΔH〈0,ΔS〈0,ΔG〈0) of Mn-TCPP-CSn bound to bovine serum albumin(BSA) show that Mn-TCPP-CSn could bind to BSA spontaneously,where the binding complex was stabilized mainly by van der Waals interactions and hydrogen bonds.These results suggest that Mn-TCPP-CSn have the advantage of becoming a potential MRI contrast agent.展开更多
Objective The purpose of this study was to correlate T2 signal intensity values in nucleus pulposus of lumbar discs with patient age,gender and stage of nucleus pulposus degeneration.Methods Lumbar imaging findings of...Objective The purpose of this study was to correlate T2 signal intensity values in nucleus pulposus of lumbar discs with patient age,gender and stage of nucleus pulposus degeneration.Methods Lumbar imaging findings of 422 cases subjects were retrospectively reviewed through T2 signal intensity values of nucleus pulposus evaluated based on the signal intensity values of MR T2-weighted mid-sagittal images of the lumbar spine,the t2 signal intensity values at all five lumbar levels (from L5-S1 to L1-L2) between male and female were used independent sample t-test and the Spearman correlation analysis.The age and grade of nucleus pulposus of disc degeneration and T2 signal intensity values were estimated by calculating and Chi-square test and the Spearman correlation analysis.The t-test was used to correlate the different anatomic levels of disc degeneration;T2 signal intensity values among the five different anatomic levels using non-parametric correlation analysis.Results There were significantly differences in T2 signal intensity values of nucleus pulposus at the same grade and anatomic level between male and female.Advanced with age,T2 signal intensity values of nucleus pulposus decreased and stage of disc degeneration increased accordingly.T2 signal intensity values may represent the nucleus pulposus degeneration of interverterbral disc.L4-L5 was the highest incidence among the nucleus pulposus degeneration of intervertebral disc.Conclusions The T2 signal intensity values based approach may be a feasible and practical tool to determine nucleus pulposus degeneration.T2 signal intensity values of nucleus pulposus of lumbar intervertebral disc are correlated with grade of degeneration and patient age.展开更多
Peptide-functionalized Au-Fe2O3 nanoparticles(termed as anti-CXCR4-Au-Fe2O3 NPs) have been constructed through conjugation of dumbbell-like Au-Fe203 NPs with C-X-C motif chemokine receptor 4(CXCR4) binding cyclic ...Peptide-functionalized Au-Fe2O3 nanoparticles(termed as anti-CXCR4-Au-Fe2O3 NPs) have been constructed through conjugation of dumbbell-like Au-Fe203 NPs with C-X-C motif chemokine receptor 4(CXCR4) binding cyclic peptide. One dumbbelMike Au-Fe2O3NP composes an Au NP[(3.3±0.3) nm in diameter] for conjugating CXCR4 binding cyclic peptide through Au-S covalent bond and a Fe2O3 NP[(8.7±0.8) nm in diameter] for using as T2-weighted magnetic resonance imaging(MRI) contrast agent. The anti-CXCR4-Au-Fe2O3 NPs have reasonable biocompatibility and integration of T2-weighted MRI contrast and tumor-targeting functionalities. The anti- CXCR4-Au-Fe2O3 NPs exhibit strong interactions with two kinds of breast tumor cells, MCF-7 cells and MDA-MB-231 cells, and high negative contrast in MRI of MDA-MB-231 tumor bearing mouse with 62% decreasing of MRI signal, indicating that the anti-CXCR4-Au-Fe2O3 NPs can recognize tumor with high efficacy and specificity.展开更多
基金the Fujian Province Clinical Key Specialty Construction Project,No.2022884Quanzhou Science and Technology Plan Project,No.2021N034S+1 种基金The Youth Research Project of Fujian Provincial Health Commission,No.2022QNA067Malignant Tumor Clinical Medicine Research Center,No.2020N090s.
文摘BACKGROUND The study on predicting the differentiation grade of colorectal cancer(CRC)based on magnetic resonance imaging(MRI)has not been reported yet.Developing a non-invasive model to predict the differentiation grade of CRC is of great value.AIM To develop and validate machine learning-based models for predicting the differ-entiation grade of CRC based on T2-weighted images(T2WI).METHODS We retrospectively collected the preoperative imaging and clinical data of 315 patients with CRC who underwent surgery from March 2018 to July 2023.Patients were randomly assigned to a training cohort(n=220)or a validation cohort(n=95)at a 7:3 ratio.Lesions were delineated layer by layer on high-resolution T2WI.Least absolute shrinkage and selection operator regression was applied to screen for radiomic features.Radiomics and clinical models were constructed using the multilayer perceptron(MLP)algorithm.These radiomic features and clinically relevant variables(selected based on a significance level of P<0.05 in the training set)were used to construct radiomics-clinical models.The performance of the three models(clinical,radiomic,and radiomic-clinical model)were evaluated using the area under the curve(AUC),calibration curve and decision curve analysis(DCA).RESULTS After feature selection,eight radiomic features were retained from the initial 1781 features to construct the radiomic model.Eight different classifiers,including logistic regression,support vector machine,k-nearest neighbours,random forest,extreme trees,extreme gradient boosting,light gradient boosting machine,and MLP,were used to construct the model,with MLP demonstrating the best diagnostic performance.The AUC of the radiomic-clinical model was 0.862(95%CI:0.796-0.927)in the training cohort and 0.761(95%CI:0.635-0.887)in the validation cohort.The AUC for the radiomic model was 0.796(95%CI:0.723-0.869)in the training cohort and 0.735(95%CI:0.604-0.866)in the validation cohort.The clinical model achieved an AUC of 0.751(95%CI:0.661-0.842)in the training cohort and 0.676(95%CI:0.525-0.827)in the validation cohort.All three models demonstrated good accuracy.In the training cohort,the AUC of the radiomic-clinical model was significantly greater than that of the clinical model(P=0.005)and the radiomic model(P=0.016).DCA confirmed the clinical practicality of incorporating radiomic features into the diagnostic process.CONCLUSION In this study,we successfully developed and validated a T2WI-based machine learning model as an auxiliary tool for the preoperative differentiation between well/moderately and poorly differentiated CRC.This novel approach may assist clinicians in personalizing treatment strategies for patients and improving treatment efficacy.
文摘Objective:To achieve precision medicine,the use of imaging methods to help the clinical detection of cerebral infarction is conducive to the clinical development of a treatment plan and increase of the cure rate and improvement of the prognosis of patients.Methods:In this work,T2-weighted imaging(T2WI),diffusion-weighted imaging(DWI),susceptibility-weighted imaging(SWI),and diffusion tensor imaging(DTI)examinations were performed on 34 patients with clinically diagnosed cerebral infarction to measure the difference in signal intensity between the lesion and its mirror area and make a comparative analysis by means of the Student-Newman-Keuls method.Results:The detection rate of T2WI was 79%(27/34),the detection rate of DWI was 97%(33/34),the detection rate of SWI was 88%(30/34),and the detection rate of DTI was 94%(32/34).Conclusion:The imaging performance was in the order DWI>DTI>SWI>T2WI for the diagnosis of cerebral infarction,and combined imaging is better than single imaging.
文摘The contrast agent concentration, the time of repetition (TR) and magnetic field strength are significant parameters that influence for the accurate signal intensity (SI) in quantitative Magnetic Resonance Imaging (MRI). Therefore, this study was conducted to investigate and refine the dependence and the optimal effect of Time of Repetition (TR) on the relationship between signal intensity and Gd-DTPA (Gadolinium-diethylene-triaminepenta-acetic acid) concentration, after applying two-dimensional (2D) Spin Echo (SE) pulse sequence under low-field MRI. In addition to that, the optimal concentration of Gd-DTPA at given sequence parameters at low-field MRI was also evaluated. A water-filled phantom was constructed for a range of Gd-DTPA concentrations (0 - 6 mmol/L) and the mean signal intensities (SIs) were assessed in the defined region of interest on T1-weighted images with different TR values (40 - 2000 ms). The generated signal-concentration curves for Gd-DTPA revealed that increasing TR was associated with the increase of the overall SIs and the maximum relationship between SI to concentration. Moreover, the required Gd-DTPA concentration to produce the maximum SI was associated to decrease with the increase of TR. In addition to this, the application of beyond 100 ms TR values in this study with relatively higher concentrations (beyond 1 - 2 mmol/L) has resulted predominantly non-linear patterns in the signal-concentration curves and it appears the saturation or decay of the SIs due to T2 effect. From these results, it can be suggested that the selection of relatively lower Gd-DTPA concentration ( mmol/L) with less than 800 ms (<800 ms) TR values can produce a better linear relationship between the concertation and SIs in T1-weighted SE low field contrast-enhanced MRI. Furthermore, this study also outlined the significance and necessity of the optimization of TR in SE sequence in low field MRI prior to a particular examination.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region, No. 2020D01A13 (to CWW)Chengdu Science and Technology Bureau, No. 2019-YF05-00511-SN (to MT)1.3.5 Project for Disciplines of Excellence, West China Hospital, Sichuan University, Nos. ZY2016102 (to MT), and ZY2016203 (to CY)
文摘According to clinical statistics,the mortality of patients with early brainstem hemorrhage is high.In this study,we established rat models of brainstem hemorrhage by injecting type Ⅶ collagenase into the right basotegmental pontine and investigated the pathological changes of early brainstem hemorrhage using multi-sequence magnetic resonance imaging and histopathological methods.We found that brainstem hematoma gradually formed in the injured rats over the first 3 days and then reduced after 7 days.The edema that occurred was mainly of the vasogenic type.No complete myelin sheath structure was found around the focus of the brainstem hemorrhage.The integrity and continuity of nerve fibers gradually deteriorated over the first 7 days.Neuronal degeneration was mild in the first 3 days and then obviously aggravated on the 7^(th)day.Inflammatory cytokines,interleukin-1β,and tumor necrosis factorαappeared on the 1st day after intracerebral hemorrhage,reached peak levels on the 3^(rd)day,and decreased from the 7^(th)day.Our findings show the characteristics of the progression of early brainstem hemorrhage.
基金supported by the National Natural Science Foundation of China,No.81271538 (to SNP)345 Talent Project and the Natural Science Foundation of Liaoning Province of China,No.2019-ZD-0794 (to SNP)+1 种基金the Natural Science Foundation of Hunan Province of China,Nos.2017JJ2225 (to JCL),2018JJ2357 (to GHL)Hunan Provincial Science and Technology Innovation Program of China,No.2017SK50203 (to HZ)。
文摘Patients with type 2 diabetes mellitus(T2 DM) often have cognitive impairment and structural brain abnormalities.The magnetic resonance imaging(MRI)-based brain atrophy and lesion index can be used to evaluate common brain changes and their correlation with cognitive function,and can therefore also be used to reflect whole-brain structural changes related to T2 DM.A total of 136 participants(64 men and 72 women,aged 55–86 years) were recruited for our study between January 2014 and December 2016.All participants underwent MRI and Mini-Mental State Examination assessment(including 42 healthy control,38 T2 DM without cognitive impairment,26 with cognitive impairment but without T2 DM,and 30 T2 DM with cognitive impairment participants).The total and sub-category brain atrophy and lesion index scores in patients with T2 DM with cognitive impairment were higher than those in healthy controls.Differences in the brain atrophy and lesion index of gray matter lesions and subcortical dilated perivascular spaces were found between non-T2 DM patients with cognitive impairment and patients with T2 DM and cognitive impairment.After adjusting for age,the brain atrophy and lesion index retained its capacity to identify patients with T2 DM with cognitive impairment.These findings suggest that the brain atrophy and lesion index,based on T1-weighted and T2-weighted imaging,is of clinical value for identifying patients with T2 DM and cognitive impairment.Gray matter lesions and subcortical dilated perivascular spaces may be potential diagnostic markers of T2 DM that is complicated by cognitive impairment.This study was approved by the Medical Ethics Committee of University of South China(approval No.USC20131109003) on November 9,2013,and was retrospectively registered with the Chinese Clinical Trial Registry(registration No.Chi CTR1900024150) on June 27,2019.
基金supported by the National Natural Science Foundation of China, Nos.82001767(to XJG), 81971577(to MMZ), 82171888(to XJX)the Natural Science Foundation of Zhejiang Province of China, Nos.LQ21H180008(to XJG), LQ20H180012(to MX)+1 种基金the China Postdoctoral Science Foundation, Nos.2021T140599(to XJG), 2019M662082(to XJG)the 13th Five-year Plan for National Key Research and Development Program of China, No.2016YFC1306600(to MMZ)
文摘Brain radiomics can reflect the characteristics of brain pathophysiology.However,the value of T1-weighted images,quantitative susceptibility mapping,and R2*mapping in the diagnosis of Parkinson’s disease(PD)was underestimated in previous studies.In this prospective study to establish a model for PD diagnosis based on brain imaging information,we collected high-resolution T1-weighted images,R2*mapping,and quantitative susceptibility imaging data from 171 patients with PD and 179 healthy controls recruited from August 2014 to August 2019.According to the inclusion time,123 PD patients and 121 healthy controls were assigned to train the diagnostic model,while the remaining 106 subjects were assigned to the external validation dataset.We extracted 1408 radiomics features,and then used data-driven feature selection to identify informative features that were significant for discriminating patients with PD from normal controls on the training dataset.The informative features so identified were then used to construct a diagnostic model for PD.The constructed model contained 36 informative radiomics features,mainly representing abnormal subcortical iron distribution(especially in the substantia nigra),structural disorganization(e.g.,in the inferior temporal,paracentral,precuneus,insula,and precentral gyri),and texture misalignment in the subcortical nuclei(e.g.,caudate,globus pallidus,and thalamus).The predictive accuracy of the established model was 81.1±8.0%in the training dataset.On the external validation dataset,the established model showed predictive accuracy of 78.5±2.1%.In the tests of identifying early and drug-naïve PD patients from healthy controls,the accuracies of the model constructed on the same 36 informative features were 80.3±7.1%and 79.1±6.5%,respectively,while the accuracies were 80.4±6.3%and 82.9±5.8%for diagnosing middle-to-late PD and those receiving drug management,respectively.The accuracies for predicting tremor-dominant and non-tremor-dominant PD were 79.8±6.9%and 79.1±6.5%,respectively.In conclusion,the multiple-tissue-specific brain radiomics model constructed from magnetic resonance imaging has the ability to discriminate PD and exhibits the advantages for improving PD diagnosis.
基金Sponsored by the National Natural Science Foundation General Program of China(Grant No.61171110)
文摘A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain order fractional Fourier domain and transformed by 4-WFRFT to compose the hybrid carrier signals. In the time domain CDMA technique is adopted for multiple accesses and time diversity gain. Compared to orthogonal frequency division multiplexing (OFDM) system, in which Fourier transform is adopted, the signal energy in HC system is distributed on the time-frequency plane more evenly and symmetrically. Thus, when there is a deep fading notch or single-frequency interference in the channel, the proposed method can split the interference to a broader range in order to reduce the influence, resulting in the better system performance. Moreover, the performances of the proposed system, such as peak-to-average power rate (PAPR) and security are also discussed in the paper.
基金Supported by the Natural Science Foundation of Hebei Province(07M003)the Doctoral Fund of Hebei Provincial Commission of Education(B2004103)
文摘A new kind of weight-Ar^λ3 (λ1, λ2, Ω)-weight is used to prove the local and global integral inequalities for conjugate A-harmonic tensors, which can be regarded as generalizations of the classical results. Some applications of the above results to quasiregular mappings are given.
文摘We report on the case of middle-aged right-handed woman with central pontine myelinolysis (CPM) revealed by high resolution structural T2-weighted FLAIR MRI imaging. There was a general flattening of Wechsler Adult Intelligence Scale—Fourth Edition subtest scores which were 1 standard deviation below expected values. In contrast Wechsler Memory Scale—Fourth Edition visual and auditory memory scores remained within the normal range. Verbal working memory appeared mildly impaired while nonverbal working memory was not. Scores on the Advanced Clinical Solution’s Social Perception battery were all in the normal range as were academic skills measured by the Wide Range Achievement Test—Fourth Edition. Performance was impaired on the Delis-Kaplan Executive Function System’s counterpart of the Trail-Making Test: Part B. Similarly, on the Draw-A-Person Test there was a discrepancy in that our patient’s standard score was 76 compared to her estimated premorbid FSIQ in the average range. She also displayed bilateral motor coordination slowing on the Finger Tapping task collectively suggesting damage to pontine motor tracts. The Minnesota Multiphasic Personality Inventory—Second Edition—Restructured Form profile was consistent with a diagnosis of severe anxiety and depression perhaps due to damage to serotoninergic neural tracts originating within the central pons. Finally, the patient displayed severe sleep disturbances and other signs of reticular activating formation injury. CPM may constitute a unique means of studying reversible subcortical lesions in the central pons in otherwise healthy subjects with benign illness. To our knowledge this is among the first patients with CPM without the usual risk factors for the disorder and who was otherwise healthy. Knowledge of the etiology and neuropsychology of such patients might aid in understanding the interaction of the fronto-ponto-cerebellar tracts in executive functions and motor programming.
文摘Background Differential diagnosis of intracranial hemorrhage and calcification is a common problem encountered in clinical imaging diagnosis. The purpose of this study was to investigate the feasibility of T2* measurement on gradient echo (GRE) T2*-weighted imaging (T2*WI) in differential diagnosis of intracranial hemorrhage and calcification. Methods Thirty-eight hemorrhagic foci in 18 patients and 11 calcification foci in seven patients were included in this study. The diagnosis of hemorrhage and calcification was confirmed in all cases with enhanced T2* weighted angiography (ESWAN) magnetic resonance imaging (MRI) and CT respectively. The significance for the difference of T2* value between the central and peripheral areas of hemorrhage and calcification lesions was tested with univariate analysis of variance, Results The detection rate of GRE T2*WI on intracranial hemorrhage was 1.9-fold higher than that of CT, especially for the hemorrhage in the brainstem and cerebellum. However, GRE T2*WI was far less sensitive to calcification than CT. There was a significant difference in the T2* value between the central area of hemorrhage and calcification (P 〈0.001), though no difference in the T2* value was obtained between the peripheral area of hemorrhage and calcification (P 〉0.05). Conclusions Quantitative measurement of T2* value on GRE T2*WI with a single MRI examination provides a fast, convenient, and effective means in differential diagnosis between intracranial hemorrhage and calcification, which may thus reduce the medical cost and save precious time for clinical management.
文摘Polyethylene glycol modified(PEGylated) NaGdF4(PEG-NaGdF4) nanoparticles as a novel T1-weighted magnetic resonance imaging(MRI) contrast agent was successfully constructed by a one-pot hydrothermal synthesis method. Because of the functionalization of PEG, the nanoprobes had excellent dispersity, excellent stability and high biocompatibility. More importantly, the as-prepared PEG-NaGdF4 nanoprobes revealed the high longitudinal relaxivity value and prominent -weighted MRI contrast performance, which was superior to the commercial MRI contrast agents. With the facile synthesis, excellent dispersity, outstanding stability, remarkable contrast performance and high biocompatibility, the PEGylated NaGdF4 nanoparticles brought more opportunities to the new generation of nanoparticulate-based T1-weighted MRI contrast agents in clinic.
基金This work is supported by the National Key R&D Program of China(2018YFA0704000)the National Natural Science Foundation of China(91859206,U21A20392,82127802 and 21921004)+2 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(ZDBS-LY-JSC004)the Scientific Instrument Developing Project of the Chi-nese Academy of Sciences(GJJSTD20200002)Xin Zhou acknowledges the support from the Tencent Foundation through the XPLORER PRIZE.
文摘Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has become the mainstream method for monitoring glycogen in the body.However,the equipment of special hard-ware to standard clinical magnetic resonance imaging(MRI)scanners limits its clinical applications.Herein,we utilized endogenous glycogen as a T_(2)-based relaxation contrast agent for imaging glycogen metabolism in the liver in vivo.The in vitro results demonstrated that the transverse relaxation rate of glycogen strongly correlates with the concentration,pH,and field strength.Based on the Swift-Connick theory,we characterized the exchange property of glycogen and measured the exchange rate of glycogen as 31,847 Hz at 37°C.Besides,the viscosity and echo spacing showed no apparent effect on the transverse relaxation rate.This unique feature enables vi-sualization of glycogen signaling in vivo through T_(2)-weighted MRI.Two hours-post intraperitoneal injection of glucagon,a clinical drug to promote glycogenolysis and gluconeogenesis,the signal intensity of the mice’s liver increased by 1.8 times from the T_(2)-weighted imaging experiment due to the decomposition of glycogen.This study provides a convenient imaging strategy to non-invasively investigate glycogen metabolism in the liver,which may find clinical applications in metabolic diseases.
基金Project supported by the National Natural Science Foundation of China.
文摘A certain weighted Herz-type Hardy space is introduced and its atom-decomposition theory is established. As applications of this theory, a boundedness theorem of sublinear operators and an interpolation theorem of linear operators on these spaces are given.
基金Supported by the National Natural Science Foundation of China(Nos.21261008, 21302071, 21171076), and the Cooperation Project of Hainan International Science and Technology, China(No.KJHZ2014-05).
文摘Mn-TCPP-CSn(n=6,1 1,20) as a type of potential magnetic resonance imaging(MRI) contrast agents were synthesized via manganese(Ⅱ) meso-tetra(4-carboxyphenyl) porphyrin(Mn-TCPP) modified with chitosan oligosaccharides(CSn).Experimental data of infared(IR),UV-Vis,MS,inductively coupled plasma-atomic emission spectrometer(ICP-AES) and size exclusion chromatography evidenced the formation of Mn-TCPP-CSn-The stability results show that Mn-TCPP-CSn in aqueous solution was stable enough to prevent Mn(Ⅱ) ions from leaking.The magnetic properties in vitro indicate that Mn-TCPP-CS20 possesses higher longitudinal relaxivity(r1=10.38 L·mmol^-1·s^-1) in aqueous solution than unmodified porphyrin Mn-TCPPNa4[manganese(Ⅱ) meso-tetra(4-carboxyphenyl) porphyrin,tetrasodium salt](r1=5.10 L·mmol^-1·s^-1) and the commercial contrast agent Gd-DTPA(r1=4.05 L·mmol^-1·s^-1).The preliminary T1-weighted flash image studies in vitro show that the contrast and the imaging signal of Mn-TCPP-CSn were superior to those of Mn-TCPPNa4 and Gd-DTPA under the same conditions.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay shows that Mn-TCPP-CSn has a good biocompatibility.In addition,the thermodynamical parameters(ΔH〈0,ΔS〈0,ΔG〈0) of Mn-TCPP-CSn bound to bovine serum albumin(BSA) show that Mn-TCPP-CSn could bind to BSA spontaneously,where the binding complex was stabilized mainly by van der Waals interactions and hydrogen bonds.These results suggest that Mn-TCPP-CSn have the advantage of becoming a potential MRI contrast agent.
文摘Objective The purpose of this study was to correlate T2 signal intensity values in nucleus pulposus of lumbar discs with patient age,gender and stage of nucleus pulposus degeneration.Methods Lumbar imaging findings of 422 cases subjects were retrospectively reviewed through T2 signal intensity values of nucleus pulposus evaluated based on the signal intensity values of MR T2-weighted mid-sagittal images of the lumbar spine,the t2 signal intensity values at all five lumbar levels (from L5-S1 to L1-L2) between male and female were used independent sample t-test and the Spearman correlation analysis.The age and grade of nucleus pulposus of disc degeneration and T2 signal intensity values were estimated by calculating and Chi-square test and the Spearman correlation analysis.The t-test was used to correlate the different anatomic levels of disc degeneration;T2 signal intensity values among the five different anatomic levels using non-parametric correlation analysis.Results There were significantly differences in T2 signal intensity values of nucleus pulposus at the same grade and anatomic level between male and female.Advanced with age,T2 signal intensity values of nucleus pulposus decreased and stage of disc degeneration increased accordingly.T2 signal intensity values may represent the nucleus pulposus degeneration of interverterbral disc.L4-L5 was the highest incidence among the nucleus pulposus degeneration of intervertebral disc.Conclusions The T2 signal intensity values based approach may be a feasible and practical tool to determine nucleus pulposus degeneration.T2 signal intensity values of nucleus pulposus of lumbar intervertebral disc are correlated with grade of degeneration and patient age.
基金Supported by the National Natural Science Foundation of China(No.80151459).
文摘Peptide-functionalized Au-Fe2O3 nanoparticles(termed as anti-CXCR4-Au-Fe2O3 NPs) have been constructed through conjugation of dumbbell-like Au-Fe203 NPs with C-X-C motif chemokine receptor 4(CXCR4) binding cyclic peptide. One dumbbelMike Au-Fe2O3NP composes an Au NP[(3.3±0.3) nm in diameter] for conjugating CXCR4 binding cyclic peptide through Au-S covalent bond and a Fe2O3 NP[(8.7±0.8) nm in diameter] for using as T2-weighted magnetic resonance imaging(MRI) contrast agent. The anti-CXCR4-Au-Fe2O3 NPs have reasonable biocompatibility and integration of T2-weighted MRI contrast and tumor-targeting functionalities. The anti- CXCR4-Au-Fe2O3 NPs exhibit strong interactions with two kinds of breast tumor cells, MCF-7 cells and MDA-MB-231 cells, and high negative contrast in MRI of MDA-MB-231 tumor bearing mouse with 62% decreasing of MRI signal, indicating that the anti-CXCR4-Au-Fe2O3 NPs can recognize tumor with high efficacy and specificity.