Objective To observe the consistency of 5.0T and 1.5T MR spectroscopy(MRS)for quantitating proton density fat fraction(PDFF)of liver.Methods Lipid emulsion models with lipid content of 0,5％,10％,15％,20％,25％and 30％were prepared.1H-MRS were collected using 5.0T and 1.5T MR scanners,respectively,and PDFF were obtained with jMRUI software.Totally 23 people,including 11 cases of fatty liver and 12 healthy adults were prospectively collected,and volume of interest(VOI)in the liver were selected to acquire 1H-MRS,and PDFF were obtained with jMRUI software and corresponding workstation,respectively.The consistencies of PDFF measured with different methods were analyzed.Results PDFF of lipid emulsion models with lipid content of 0,5％,10％,15％,20％,25％and 30％measured with jMRUI software and workstations based on 5.0T and 1.5T 1H-MRS all had good consistencies and being positively correlated,so were PDFF of liver tissue measured with jMRUI software and workstations based on 5.0T and 1.5T 1H-MRS.Conclusion 5.0T and 1.5T 1H-MRS had good consistency for quantitating liver PDFF.Measuring liver PDFF with workstation in clinical practice was helpful to simplifying workflow.

Objective To observe the value of susceptibility weighted imaging(SWI)based on 5.0T MRI for diagnosing hepatocellular carcinoma(HCC)complicated with vein tumor thrombi.Methods Totally 63 HCC patients were retrospectively enrolled,among them 17 complicated with vein tumor thrombi.The efficacy of 5.0T SWI for detecting vein tumor thrombus was observed,and the image quality were compared between 5.0T and 3.0T.Results 5.0T SWI displayed vein tumor thrombi in 16 cases,except for 1 case with vein tumor thrombi in the upper segment of the left lateral lobe of the left portal vein.The liver edge score,overall image quality score,signal-to-noise ratio and contrast-to-noise ratio of portal venous phase and hepatobiliary phase in 5.0T enhanced MRI were all higher than those in 3.0T(all P＜0.05).Conclusion 5.0T SWI was helpful for diagnosing HCC complicated with vein tumor thrombi.

Objective To compare image quality of 5.0T and 3.0T non-contrast MRI for displaying insulinoma.Methods Twelve patients with insulinoma were prospectively enrolled,and non-contrast abdominal T1WI,T2WI as well as diffusion-weighted imaging(DWI)were acquired using 5.0T and 3.0T MR scanners,respectively.The subjective scores of image quality of each sequence of 5.0T and 3.0T MRI,also of tumor-pancreas parenchyma contrast scores were compared.The signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of insulinomas were observed,and the displayed rate of insulinoma by each sequence and overall MRI were compared.Results The subjective scores of 5.0T T1WI and DWI were higher than those of 3.0T T1WI and DWI(both P＜0.05),but not significantly different between 5.0T and 3.0T T2WI(P=0.166).Furthermore,the tumor-pancreas parenchyma contrast score of 5.0T T1WI was higher than that of 3.0T T1WI(P=0.023),but not significantly different between 5.0T and 3.0T T2WI,nor between 5.0T and 3.0T DWI(both P＞0.05).SNR of insulinomas on 5.0T T2WI were higher than on 3.0T T2WI(P=0.015),however,no significant difference of SNR was found between 5.0T and 3.0T T1WI,nor between 5.0T and 3.0T DWI(both P＞0.05).CNR of insulinomas on all 5.0T MRI were not significantly different with those on 3.0T MRI(all P＞0.05).The displayed rate of insulinoma on 5.0T T1WI,T2WI and DWI was 100％(12/12),66.67％(8/12)and 83.33％(10/12),respectively,on 3.0TT1WI,T2WI and DWI was 75.00％(9/12),58.33％(7/12),66.67％(8/12),respectively.The overall displayed rate of insulinoma on 5.0T and 3.0T MRI was 100％(12/12)and 83.33％(10/12),respectively.Conclusion Compared with 3.0T MRI,5.0T MRI was superior for displaying insulinoma,hence being helpful for diagnosis.

Objective To compare image quality of 3.0T and 5.0T MR cholangiopancreatography(MRCP).Methods Eighteen patients with bile duct dilation(bile duct dilation group)and 7 healthy volunteers(healthy group)were prospectively enrolled.MRCP was performed with 3.0T and 5.0T scanners,respectively,and the ability for displaying details of bile duct tree,signal-to-noise ratio(SNR)and image artifacts were compared between 3.0T and 5.0T MRCP.Results In bile duct dilation group,the number of branches,total branch length and the maximum branch length of bile duct tree on 5.0T MRCP were all greater than those on 3.0T MRCP(all P＜0.05).In healthy group,the number of branches and total branch length of bile duct tree on 5.0T MRCP were both greater than those on 3.0T MRCP(both P＜0.05).In both groups,the SNR of 5.0T MRCP was greater than that of 3.0T MRCP,but the difference was not significant(both P＞0.05).No significant difference of image artifacts was found between 3.0T and 5.0T MRCP(P=0.054).Conclusion 5.0T MRCP might display better anatomical details of bile duct tree than 3.0T MRCP,with SNR and image artifacts comparable to 3.0T MRCP.

Non-contrast enhanced MR angiography(NCE-MRA)has been widely used in clinic since advantages of non-radiation and non-contrast media.The image quality of NCE-MRA could be effectively improved using ultra-high field MR scanner,yet 7.0T devices were limited by coils and usually used for cerebrovascular scanning.The invention of 5.0T ultra-high field MR system brings new opportunities for whole body NCE-MRA.The preliminary application of 5.0T whole body NCE-MRA in human body were explored in this article.

Objective To observe the drainage pathways of interstitial fluid(ISF)and substance clearance pattern in rat brain with fluorescence tracing imaging and treacer-based MRI.Methods Thirty-three male SD rats were randomly divided into fluorescence tracing group(F group,n=18)and treacer-based MRI group(MRI group,n=15),then further divided into thalamic,hippocampal and caudate nucleus subgroups,respectively.Evans blue was injected to rats in F group,and cardiac perfusion was performed after injection,then brain tissue was harvested,and frozen sections were made to observe the drainage pathways of IFS in different subgroups.MRI was performed on rats in MRI group before and after injection of gadolinium-diethylenetriamine pentaacetic acid(Gd-DTPA)to observe signal intensity in ROI of brain regions in different subgroups,the signal unit ratio was calculated,and the changing trend was explored.Results ISF in thalamus,hippocampus and caudate nucleus had different dominant drainage pathways,and the time of tracer reached to adjacent brain regions and whole brain in F group were different.In MRI group,within 4 h after injection of Gd-DTPA,there were differences in direction and clearance rate among tracer in thalamus,hippocampus and caudate nucleus,mainly manifesting as the tracer in thalamus and hippocampus drained to the ipsilateral cortex and lateral ventricle,while the tracer in the caudate nucleus diffused to the cortex and midbrain,and there were differences of the peak time of tracer signal among adjacent drainage brain regions.Conclusion Fluorescence and MR dual-mode imaging showed that there were differences in the dominant drainage pathways of IFS and clearance rates of small molecule substances among hypothalamus,hippocampus and caudate nucleus of rats.

Objective To observe the reproducibility of radiomics feature(RF)extracted from virtual monoenergetic image(VMI)of rabbit VX2 hepatoma models obtained with 3 different dual-energy CT(DECT)systems,and to explore relationship of reproducibility and diagnostic performance of RF.Methods Fifteen rabbits with VX2 hepatoma were randomly divided into 3 groups(each n=5).Contrast-enhanced abdominal CT scanning under volume CT dose index(CTDIvol)levels of 6,9 and 12 mGy were performed with dual-source DECT(dsDECT),rapid kV switching DECT(rsDECT)and dual-layer detector DECT(dlDECT),respectively.VMI were reconstructed at 10 keV increments from 40 to 140 keV.RF were extracted from VMI,the reproducibility was assessed using intra-class correlation coefficient(ICC),and those with ICC≥0.8 were considered as reproducible RF.The percentage of reproducible features(denoted by R)were compared among different scanner pairings and different CTDIvol levels.Within each CTDIvol group,the reconstruction energy levels yielding the maximum number(denoted by N)of common RF across different scanner pairings were identified.The receiver operating characteristic(ROC)curve was drawn,the area under the curve(AUC)was calculated,and the diagnostic efficacies of reproducible RF and other RF were compared under optimal reproducible conditions.Spearman correlation coefficient between ICC and the corresponding AUC of RF were calculated.Results RrsDECT-dsDECT(6.45％,95％CI[2.36％,8.87％])was higher than RdlDECT-dsDECT(0.72％,95％CI[0.15％,1.79％])and RrsDECT-dlDECT(1.43％,95％CI[0.60％,4.06％])(all adjusted P＜0.05),R9mGy(3.70％,95％CI[1.31％,5.73％])and R12mGy(2.63％,95％CI[0.60％,6.69％])were higher than R6mGy(1.31％,95％CI[0.12％,1.55％])(all adjusted P＜0.05).The optimal reproducible reconstruction energy levels of RF under CTDIvol of 6,9 and 12 mGy concentrated at 50-70 keV.AUC of reproducible RFs were higher than of other RF(all adjusted P＜0.05)and had certain correlation with the reproducibility(rs=0.102-0.516,P＜0.05).Conclusion The reproducibility of RF extracted from contrast-enhanced VMI CT images of rabbit VX2 hepatoma models associated with DECT scanner,CTDIvol level and reconstruction energy level.RF with higher reproducibility might have better diagnostic performance.

Objective To observe the relationship between functional connectivity(FC)of frontoparietal network(FPN)and cognitive function in patients with cerebral small vessel disease(CSVD)using resting-state functional MRI(rs-fMRI).Methods rs-fMRI of 50 CSVD patients with cognitive impairment(CI group),65 CSVD patients with normal cognition(NC group)and 60 healthy controls(HC group),as well as outcomes of neuropsychological tests were retrospectively analyzed.Brain regions with different FC of FPN were compared among 3 groups and between each 2 groups.Partial correlation analysis was used to evaluate the correlations of FC of brain regions value being statistically different between CI and NC groups and cognitive scores.Results Significant differences of FC in bilateral cingulate gyrus,left middle frontal gyrus,right supramarginal gyrus,right inferior parietal lobule and right medial superior frontal gyrus were found among groups(FWE correction,all P＜0.05).Compared with NC group,FC of left cingulate gyrus decreased,of right inferior frontal gyrus and right medial superior frontal gyrus increased in CI group(FWE correction,all P＜0.05).The decreased FC value of left cingulate gyrus was negatively correlated with clock drawing test score in CSVD patients(r=-0.159,P=0.049).Conclusion CSVD patients with or without CI had extensive abnormal FC of FPN,and the left cingulate gyrus was associated with patient's cognitive function.

Objective To explore the impact of δ-catenin expression level on resting-state brain function in breast cancer patients.Methods Totally 104 female breast cancer patients were prospectively enrolled and divided into δ-catenin high expression group(DH group,n=51)and δ-catenin low expression group(DL group,n=53)according to δ-catenin expression level,while 36 female healthy volunteers were selected as controls(control group).Neuropsychological tests were performed,and resting-state functional MRI(rs-fMRI)were acquired,then parameters of brain function,including amplitude of low frequency fluctuation(ALFF),fractional ALFF(fALFF),regional homogeneity(ReHo)and functional connectivity strength(FCS)of brain regions with differences among groups were obtained.Spearman correlation analysis was used to evaluate the correlations of function parameters of brain regions with general data and neuropsychological test scores.Results Significant differences of fALFF,ReHo and FCS values were found among 3 groups(familywise error rate[FWE]correction,all P＜0.05).fALFF value of left inferior temporal gyrus in DH and DL groups were both higher than that in control group(FWE correction,both P＜0.05),ReHo value of right inferior temporal gyrus in DH group,as well as of right middle temporal gyrus,right inferior temporal gyrus and right fusiform gyrus in DL group were all lower than that in control group(FWE correction,all P＜0.05),FSC value of left lenticular nucleus,left putamen,left fusiform gyrus,left calcarine fissure surrounding cortex and left inferior temporal gyrus in DH group were all higher than that in DL group(FWE correction,all P＜0.05),FSC value of left lenticular nucleus,left putamen,left fusiform gyrus and left calcarine fissure surrounding cortex in DH group were all higher than that in control group(FWE correction,all P＜0.05),while FSC value of left lingual gyrus,left lenticular nucleus and left putamen were both higher than that in control group(FWE correction,both P＜0.05).In brain regions with different fMRI indexes between DH group and DL group,FSC values were lowly positively correlated with CogPCA results(r=0.313,P＜0.05).In brain regions with different fMRI indexes between DH group and control group,fALFF value were lowly positively correlated with trail making test A(TMT A)and trail making test B(TMT B)(r=0.301,0.310,both P＜0.05),ReHo values were lowly negatively correlated with TMT B(r=-0.307,P＜0.05),FCS values were weakly/lowly positively correlated with TMT A and TMT B(r=0.282,0.309,both P＜0.05)and lowly negatively correlated with results of digital symbol substitution test(DSST)(r=-0.363,P＜0.05).In brain regions with different fMRI indexes between DL group and control group,fALFF values were weakly/lowly negatively correlated with results of mini mental state examination(MMSE),Montreal cognitive assessment(MoCA),auditory verbal learning test(AVLT)short-term memory and DSST(r=-0.399,-0.362,-0.344,-0.288,all P＜0.05).Conclusion The expression level of δ-catenin had certain impact on brain function of breast cancer patients,resulted in asymmetry changes of brain network in bilateral hemispheres,as well as memory loss through affecting left inferior temporal gyrus,left lenticular nucleus,left putamen and left fusiform gyrus.

Objective To observe the correlations of clinical,multi-modal ultrasonic and pathological features of papillary thyroid carcinoma(PTC)with BRAF V600E mutation.Methods Patients with clinically suspected malignant thyroid lesions were prospectively collected.After the results of pathology and gene test were obtained,PTC patients were divided into BRAF V600E mutation(+)(mutant group)and BRAF V600E mutation(-)(wild-type group)according to BRAF V600E gene test.Univariate analysis and multivariate logistic regression were used to compare clinical,conventional ultrasound,contrast-enhanced ultrasound(CEUS)and pathological manifestations between groups,so as to screen the independent risk factors of PTC BRAF V600E gene mutation.Results A total of 116 PTC patients(116 lesions)were enrolled,including 77 in mutant group and 39 in wild-type group.Statistical differences of thyroid peroxidase antibody(TPO-Ab)level,lesion size,orientation,margin and microcalcification observed on conventional ultrasound,changes of lesion size and the mean transit time(MTT)shown on CEUS,as well as of extramembranous invasion,cervical central lymph node metastasis,complicated with benign nodules shown by pathology were found between groups(all P＜0.05).TPO-Ab level,lesion orientation and changes of lesion size after enhancement shown by multi-modal ultrasound,and pathological cervical central lymph node metastasis were all independent predictive factors for PTC BRAF V600E gene mutation(OR=0.175,3.868,5.769,6.943,all P＜0.05).Conclusion Patients'TPO-Ab level,lesion orientation,changes of lesion size after enhancement shown by multi-modal ultrasound and pathological cervical central lymph node metastasis were all independently associated with PTC BRAF V600E gene mutation.