Gadoxetic acid-enhanced magnetic resonance imaging in the assessment of hepatic sinusoidal obstruction syndrome in a mouse model

BACKGROUND Neoadjuvant chemotherapy can cause hepatic sinusoidal obstruction syndrome(SOS)in patients with colorectal cancer liver metastases and increases posto-perative morbidity and mortality.AIM To evaluate T1 mapping based on gadoxetic acid-enhanced magnetic resonance imaging(MRI)for diagnosis of hepatic SOS induced by monocrotaline.METHODS Twenty-four mice were divided into control(n=10)and experimental(n=14)groups.The experimental groups were injected with monocrotaline 2 or 6 days before MRI.MRI parameters were:T1 relaxation time before enhancement;T1 relaxation time 20 minutes after enhancement(T_(1post));a reduction in T1 relaxation time(△T_(1)%);and first enhancement slope percentage of the liver parenchyma(ESP).Albumin and bilirubin score was determined.Histological results served as a reference.Liver parenchyma samples from the control and experimental groups were analyzed by western blotting,and organic anion transporter polypeptide 1(OATP1)was measured.RESULTS T_(1post),△T_(1)%,and ESP of the liver parenchyma were significantly different between two groups(all P<0.001)and significantly correlated with the total histological score of hepatic SOS(r=-0.70,0.68 and 0.79;P<0.001).△T_(1)%and ESP were positively correlated with OATP1 levels(r=0.82,0.85;P<0.001),whereas T_(1post) had a negative correlation with OATP1 levels(r=-0.83;P<0.001).INTRODUCTION Hepatic sinusoidal obstruction syndrome(SOS)is also known as hepatic veno-occlusive disease of the liver[1].The main pathological feature of hepatic SOS is damage to liver terminal vessels,and the clinical symptoms of it include ascites and abdominal pain[2].It was first proposed in 1979 as an early complication of hematopoietic stem cell transplantation[3].The prevalence ranges from 5%to 60%,and hepatic SOS is a potentially severe complication and can even lead to death in severe cases[4].Recently,systemic neoadjuvant chemotherapy became widely regarded as one of the causes hepatic SOS in the patients with advanced metastatic colorectal cancer[5,6],especially those were treated with oxaliplatin[7,8].Oxaliplatin-based preoperative chemotherapy is used for patients with colorectal liver metastases as the standard regimen[8,9],because it could improve tumor resection outcome by shrinking the metastatic sites and reducing recurrence rate[10].Nevertheless,chemotherapy-induced hepatic SOS has been associated with a higher risk of postresection morbidity[11],such as intraoperative bleeding,intraoperative transfusions,and postoperative liver failure[12].Therefore,it is important to detect and diagnose of hepatic SOS timely.Currently,the gold standard is still based on liver biopsy[13],but it is an invasive procedure and has several limitations and complications,such as hemorrhage[14].A noninvasive diagnostic modality is needed for the assessment of hepatic SOS.Some noninvasive tools have been used for diagnosis of hepatic SOS.Researchers have utilized a preoperative platelet count and aspartate aminotransferase to platelet ratio index[15].In addition,some imaging methods such as shear wave ultrasonography,computed tomography,and gadoxetic acid-enhanced magnetic resonance imaging(MRI)have been promoted as useful methods for evaluation of hepatic SOS[16-18].Recent studies with monocrotaline(MCT)-treated rats were conducted to investigate diagnosis and prediction of severity of SOS.For example,intravoxel incoherent motion diffusion-weighted imaging,non-Gaussian diffusion models,and T1 rho quantification[19,20].The MCT-induced hepatic SOS animal model was reproducible,with a detailed pathological scoring criteria[21].Gadoxetic acid is a hepatocyte-specific contrast substance,which can provide parenchymal contrast in the hepato-biliary phase.It is reported that gadoxetic acid is absorbed into the liver parenchyma via organic anion transporter polypeptide 1(OATP1)on the hepatocyte membranes[22-24].Recently,several authors have described the feasibility of gadoxetic acid-enhanced MRI for the diagnosis of oxaliplatin-induced hepatic SOS[25].They mainly diagnosed hepatic SOS based on the signal intensity of the hepatobiliary specific phase.However,there were several limitations due to the inconsistency between signal intensity of the liver parenchyma and the concentration of contrast agent for evaluation of the degree of hepatic SOS[26].Therefore,we measured T1 relaxation time on parametric mapping because it is linearly related to the concentration of the contrast agent and is not affected by other factors[27].Yang et al[28]demonstrated T1 mapping on gadoxetic acid-enhanced MRI for the assessment of oxaliplatin-induced liver injury in a C57BL/6 mouse model.However,the main pathological changes in their model were hepatocyte degeneration and fibrosis.Therefore,we aimed to explore the effectiveness of T1 mapping based on gadoxetic acid-enhanced MRI for the diagnosis of hepatic SOS in a C57BL/6 mouse model,as well as a possible relation between OATP1 Levels and MRI parameters.

Multimodality imaging using proton magnetic resonance spectroscopic imaging and ^(18)F-fluorodeoxyglucose-positron emission tomography in local prostate cancer

AIM To assess the relationship using multimodality imaging between intermediary citrate/choline metabolism as seen on proton magnetic resonance spectroscopic imaging(1H-MRSI) and glycolysis as observed on ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG-PET/CT) in prostate cancer(PCa) patients. METHODS The study included 22 patients with local PCa who were referred for endorectal magnetic resonance imaging/1HMRSI(April 2002 to July 2007) and ^(18)F-FDG-PET/CT and then underwent prostatectomy as primary or salvage treatment. Whole-mount step-section pathology was used as the standard of reference. We assessed the relationships between PET parameters [standardized uptake value(SUVmax and SUVmean)] and MRSI parameters [choline + creatine/citrate(CC/Cmax and CC/Cmean) and total number of suspicious voxels] using spearman's rank correlation, and the relationships of PET and 1H-MRSI index lesion parameters to surgical Gleason score.RESULTS Abnormal intermediary metabolism on 1H-MRSI was present in 21/22 patients, while abnormal glycolysis on ^(18)F-FDG-PET/CT was detected in only 3/22 patients. Specifically, index tumor localization rates were 0.95(95%CI: 0.77-1.00) for 1H-MRSI and 0.14(95%CI: 0.03-0.35) for ^(18)F-FDG-PET/CT. Spearman rank correlations indicated little relationship(ρ =-0.36-0.28) between 1H-MRSI parameters and ^(18)F-FDG-PET/CT parameters. Both the total number of suspicious voxels(ρ = 0.55, P = 0.0099) and the SUVmax(ρ = 0.46, P = 0.0366) correlated weakly with the Gleason score. No significant relationship was found between the CC/Cmax, CC/Cmean or SUVmean and the Gleason score(P = 0.15-0.79). CONCLUSION The concentration of intermediary metabolites detected by 1H MRSI and glycolytic flux measured ^(18)F-FDG PET show little correlation. Furthermore, only few tumors were FDG avid on PET, possibly because increased glycolysis represents a late and rather ominous event in the progression of PCa.

Magnetic resonance imaging focused on the ferritin heavy chain 1 reporter gene detects neuronal differentiation in stem cells

The neuronal differentiation of mesenchymal stem cells offers a new strategy for the treatment of neurological disorders.Thus,there is a need to identify a noninvasive and sensitive in vivo imaging approach for real-time monitoring of transplanted stem cells.Our previous study confirmed that magnetic resonance imaging,with a focus on the ferritin heavy chain 1 reporter gene,could track the proliferation and differentiation of bone marrow mesenchymal stem cells that had been transduced with lentivirus carrying the ferritin heavy chain 1 reporter gene.However,we could not determine whether or when bone marrow mesenchymal stem cells had undergone neuronal differentiation based on changes in the magnetic resonance imaging signal.To solve this problem,we identified a neuron-specific enolase that can be differentially expressed before and after neuronal differentiation in stem cells.In this study,we successfully constructed a lentivirus carrying the neuron-specific enolase promoter and expressing the ferritin heavy chain 1 reporter gene;we used this lentivirus to transduce bone marrow mesenchymal stem cells.Cellular and animal studies showed that the neuron-specific enolase promoter effectively drove the expression of ferritin heavy chain 1 after neuronal differentiation of bone marrow mesenchymal stem cells;this led to intracellular accumulation of iron and corresponding changes in the magnetic resonance imaging signal.In summary,we established an innovative magnetic resonance imaging approach focused on the induction of reporter gene expression by a neuron-specific promoter.This imaging method can be used to noninvasively and sensitively detect neuronal differentiation in stem cells,which may be useful in stem cell-based therapies.

Role of advanced magnetic resonance imaging in the assessment of malignancies of the mediastinum

In the new era of functional magnetic resonance imaging(MRI), the utility of chest MRI is increasing exponentially due to several advances, including absence of ionizing radiation, excellent tissue contrast and high capability for lesion characterization and treatment monitoring. The application of several of these diagnostic weapons in a multiparametric fashion enables to better characterize thymic epithelial tumors and other mediastinal tumoral lesions, accurate assessment of the invasion of adjacent structures and detection of pathologic lymph nodes and metastasis. Also, "do not touch lesions" could be identified with the associated impact in the management of those patients. One of the hotspots of the multiparametric chest MR is its ability to detect with acuity early response to treatment in patients with mediastinal malignant neoplasms. This has been related with higher rates of overall survival and progression free survival.Therefore, in this review we will analyze the current functional imaging techniques available(18 F-Fluorodeoxiglucose positron emission tomography/computed tomography, diffusion-weighted imaging, dynamic contrast-enhanced MRI, diffusion tensor imaging and MR spectroscopy) for the evaluation of mediastinal lesions, with a focus in their correct acquisition and post-processing. Also, to review the clinical applications of these techniques in the diagnostic approach of benign and malignant conditions of the mediastinum.

Quantitative multiparametric magnetic resonance imaging can aid non-alcoholic steatohepatitis diagnosis in a Japanese cohort

BACKGROUND Non-invasive assessment of non-alcoholic steatohepatitis(NASH)is increasing in desirability due to the invasive nature and costs associated with the current form of assessment;liver biopsy.Quantitative multiparametric magnetic resonance imaging(mpMRI)to measure liver fat(proton density fat fraction)and fibroinflammatory disease[iron-corrected T1(cT1)],as well as elastography techniques[vibration-controlled transient elastography(VCTE)liver stiffness measure],magnetic resonance elastography(MRE)and 2D Shear-Wave elastography(SWE)to measure stiffness and fat(controlled attenuated parameter,CAP)are emerging alternatives which could be utilised as safe surrogates to liver biopsy.AIM To evaluate the agreement of non-invasive imaging modalities with liver biopsy,and their subsequent diagnostic accuracy for identifying NASH patients.METHODS From January 2019 to February 2020,Japanese patients suspected of NASH were recruited onto a prospective,observational study and were screened using noninvasive imaging techniques;mpMRI with LiverMultiScan®,VCTE,MRE and 2DSWE.Patients were subsequently biopsied,and samples were scored by three independent pathologists.The diagnostic performances of the non-invasive imaging modalities were assessed using area under receiver operating characteristic curve(AUC)with the median of the histology scores as the gold standard diagnoses.Concordance between all three independent pathologists was further explored using Krippendorff’s alpha(a)from weighted kappa statistics.RESULTS N=145 patients with mean age of 60(SD:13 years.),39%females,and 40%with body mass index≥30 kg/m2 were included in the analysis.For identifying patients with NASH,MR liver fat and cT1 were the strongest performing individual measures(AUC:0.80 and 0.75 respectively),and the mpMRI metrics combined(cT1 and MR liver fat)were the overall best non-invasive test(AUC:0.83).For identifying fibrosis≥1,MRE performed best(AUC:0.97),compared to VCTE-liver stiffness measure(AUC:0.94)and 2D-SWE(AUC:0.94).For assessment of steatosis≥1,MR liver fat was the best performing non-invasive test(AUC:0.92),compared to controlled attenuated parameter(AUC:0.75).Assessment of the agreement between pathologists showed that concordance was best for steatosis(a=0.58),moderate for ballooning(a=0.40)and fibrosis(a=0.40),and worst for lobular inflammation(a=0.11).CONCLUSION Quantitative mpMRI is an effective alternative to liver biopsy for diagnosing NASH and non-alcoholic fatty liver,and thus may offer clinical utility in patient management.

Relationships among magnetic resonance imaging, histological findings, and IGF-I in steroid-induced osteonecrosis of the femoral head in rabbits

Objective: To study the relationships among magnetic resonance imaging (MRI), histological findings, and insu- lin-like growth factor-I (IGF-I) in steroid-induced osteonecrosis of the femoral head in rabbits. Methods: Thirty rabbits were randomly divided into experimental Group A (n=15) and control Group B (n=15). The 7.5 mg/kg (2 ml) of dexamethasone (DEX) and physiological saline (2 ml) were injected into the right gluteus medius muscle twice at one-week intervals in animals of Groups A and B, respectively. At 4, 8 and 16 weeks after obtaining an MRI, the rabbits were sacrificed and the femoral head from one side was removed for histological study of lacunae empty of osteocytes, subchondral vessels, and size of fat cells under microscopy, and the femoral head from the other side was removed for enzyme-linked immunoadsorbent assay (ELISA) for IGF-I. Results: At 4, 8 and 16 weeks after treatment, no necrotic lesions were detected in Group B, while they were detected in Group A. Light microscopy revealed that the fat cells of the marrow cavity were enlarged, subchondral vessels were evidently decreased, and empty bone lacunae were clearly increased. The IGF-I levels in Group A were significantly higher than those in Group B. At 8 weeks after the DEX injection, the MRI of all 20 femora showed an inhomogeneous, low signal intensity area in the femoral head, and at 16 weeks, the findings of all 10 femora showed a specific "line-like sign". The MRI findings of all femora in Group B were normal. Conclusion: MRI is a highly sensitive means of diagnosing early experimental osteonecrosis of the femoral head. However, the abnormal marrow tissues appeared later than 4 weeks when the expression of IGF-I increased. This reparative factor has an early and important role in response to steroid-induced osteonecrosis of the femoral head, and provides a theoretical foundation for understanding the pathology and designing new therapies.

3.0T 1H magnetic resonance spectroscopy for assessment ofsteatosis in patients with chronic hepatitis C

AIM To investigate the utility of 1H magneticresonance spectroscopy （1H MRS） as a noninvasivetest for steatosis in patients infected with hepatitis Cvirus.METHODS： Ninety patients with chronic hepatitisC and pathology data underwent 3.0T 1H MRS, andthe results of MRS and pathological analysis werecompared.RESULTS： This group of patients included 26 peoplewith mild fatty liver （28.89%）, 16 people withmoderate fatty liver （17.78%）, 18 people with severefatty liver （20.0%）, and 30 people without fatty liver（33.33%）. The water peak was near 4.7 parts permillion （ppm）, and the lipid peak was near 1.3 ppm.Analysis of variance revealed that differences in thelipid peak, the area under the lipid peak, ratio of thelipid peak to the water peak, and ratio of the areaunder the lipid peak to the area under the waterpeak were statistically significant among the groups.Specifically, as the severity of fatty liver increased, thevalue of each index increased correspondingly. In thepairwise comparisons, the mean lipid peak, area underthe lipid peak, ratio of the lipid peak to the waterpeak, and ratio of the area under the lipid peak to thearea under the water peak were significantly differentbetween the no fatty liver and moderate fatty liver groups, whereas no differences were noted betweenthe severe fatty liver group and the mild or moderatefatty liver group. Area under the ROC curve （AUC） ofarea ratio in lipid and water and ratio in lipid and waterin the no fatty liver group to mild fatty liver group, mildfatty liver group to moderate fatty liver group, andmoderate fatty liver disease group to severe fatty livergroup, were 0.705, 0.900, and 0.975, respectively.CONCLUSION： 1H MRS is a noninvasive techniquethat can be used to provide information on the effectof liver steatosis on hepatic metabolic processes. Thisstudy indicates that the 1H MRS can be used as anindicator of steatosis in patients with chronic hepatitis C.

A multiple-tissue-specific magnetic resonance imaging model for diagnosing Parkinson’s disease: a brain radiomics study

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.

Overview and progress of X-nuclei magnetic resonance imaging in biomedical studies

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.

Three dimensional structure prediction and proton nuclear magnetic resonance analysis of toxic pesticides in human blood plasma

The purpose of this study was to investigate the nuclear magnetic resonance （NMR） assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural prop- erties of highly toxic pesticides were investigated using the PreADME analysis. We observed that toxic pesticides possessed higher molecular weight and, more hydrogen bond donors and acceptors when compared with less toxic pesticides. The occurrence of functional groups and structural properties was analyzed using ~H-NMR. The ~H- NMR spectra of the phosphomethoxy class of pesticides were characterized by methyl resonances at 3.7-3.9 ppm （8） with the coupling constants of 11-16 Hz （Je-cns）. In phosphoethoxy pesticides, the methyl resonance was about 1.4 ppm （8） with the coupling constant of 10 Hz （Je-cH2） and the methylene resonances was 4.2-4.4 ppm （8） with the coupling constant of 0.8 Hz （Jp-cH3）, respectively. Our study shows that the values of four parameters such as chemical shift, coupling constant, integration and relaxation time correlated with the concentration of toxic pesticides, and can be used to characterise the proton groups in the molecular structures of toxic pesticides.

^(1)H-MRS在脑胶质瘤诊断中的研究进展

脑胶质瘤是中枢神经系统最常见的颅内恶性肿瘤,预后差。磁共振波谱成像作为能够无创检测活体组织内化学物质的磁共振功能成像,可以量化感兴趣区的不同代谢物,为更加准确地早期诊断脑胶质瘤提供帮助。本文就氢质子磁共振波谱成像在脑胶质瘤诊断评估中的研究进展进行综述。

Applications of multi-nuclear magnetic resonance spectroscopy at 7T

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.

利用^1H MRS进行在体乳腺癌中复合胆碱外参照法定量的研究

目的探讨如何用外参照法利用氢质子磁共振波谱(1HMRS)对在体乳腺癌中的复合胆碱进行绝对定量。方法配制5个不同浓度的胆碱测试模型及一个胆碱校对模型。在基本相同的条件下,对各测试模型的同一位置进行MRS采集,统计胆碱峰峰下面积与胆碱浓度之间是否呈线性相关。对水模进行T1WI成像,绘制不同位置信号强度的变化曲线。对同一校对模型的同一位置采用不同大小的体素进行MRS采集,统计体素大小与胆碱峰峰下面积是否呈线性相关。测量胆碱测试模型及校对模型中胆碱的T1及T2值。验证胆碱浓度绝对定量的校对公式。对7例乳腺癌病人进行乳腺MRS采集,利用校对公式以胆碱校对模型中的胆碱浓度为参照计算出乳腺癌中复合胆碱的浓度。结果胆碱测试模型的胆碱峰峰下面积与胆碱浓度之间呈线性相关。同一模型同一位置胆碱峰峰下面积与体素大小呈线性相关。测试模型及校对模型中胆碱的T1及T2值分别为1902.5/1032.8、2426.3/989.4。利用校对公式估计出的校对模型的胆碱浓度为(5.2±1.0)mM,与校对模型的实际浓度比较二者无显著差异(t=0.6,P>0.05)。7例乳腺癌中的复合胆碱浓度为(3.64±2.52)mM。结论外参照法是进行乳腺癌中复合胆碱浓度定量的可行及可靠的方法。

短暂性脑缺血发作与脑梗死的1^H-MRS比较研究

目的比较短暂性脑缺血发作(TIA)和脑梗死的氢质子磁共振波谱(1H-MRS)改变,探讨1H-MRS在TIA中的应用价值。资料与方法对30例TIA和24例脑梗死患者行1H-MRS检查,同期选择24名健康志愿者作为对照。分别比较TIA患者病变侧和对侧半卵圆中心、脑梗死患者梗死灶与对侧正常脑组织代谢物氮-乙酰天门冬氨酸(NAA)、胆碱(Cho)和肌酸(Cr)含量的差异,并观察有无乳酸(Lac)峰出现,再对TIA患者、脑梗死患者及正常对照组之间脑内NAA、Cho、Cr和Lac含量的差异进行比较。结果TIA患者病变侧半卵圆中心NAA降低、Cho升高,与对侧相应区域以及正常对照组比较差异均有统计学意义(P<0.01),而两侧Cr含量差异无统计学意义(P>0.05),脑梗死患者梗死灶内NAA、Cho和Cr与对侧正常脑组织和正常对照组比较均有下降,差异有统计学意义(P<0.01),但TIA患者NAA下降幅度明显小于脑梗死患者,差异有统计学意义(P<0.01);10例TIA患者、23例脑梗死患者于病侧发现Lac峰,TIA的Lac含量低于脑梗死,差异有统计学意义(P<0.01)。结论TIA患者缺血脑组织存在代谢异常,但较脑梗死轻微,1H-MRS能够早期发现这种异常,对TIA的早期诊断和治疗具有重要价值。

基于MRI影像组学构建PD-1/PD-L1抑制剂治疗dMMR/MSI-H直肠癌疗效的预测模型

目的:探讨MRI影像组学模型在程序性细胞死亡蛋白-1(PD-1)/程序性细胞死亡-配体1(PD-L1)抑制剂联合全程新辅助治疗(TNT)局部进展期直肠癌(LARC)的疗效预测价值。方法:收集河南中医药大学第一附属医院PD-1/PD-L1抑制剂联合TNT治疗的80例错配修复基因缺陷(dMMR)/微卫星高度不稳定(MSI-H)基因型中低位LARC患者的临床和影像资料。将入组患者按7∶3比例分为训练集和测试集,提取影像组学特征,从中筛选并构建影像组学模型。描绘影像组学模型的Rad-score与病理金标准之间的受试者工作特征(ROC)曲线,计算曲线下面积(AUC),并评价模型的诊断效能。采用决策曲线分析(DCA)计算风险阈值的范围,并评估临床获益情况。收集湖南省人民医院25例dMMR/MSI-H基因型LARC患者的影像资料作为外部验证集。结果:训练集、测试集及外部验证集三者之间的临床特征无统计学差异(P>0.05)。经过降维处理、t检验及一致性检验以及LASSO交叉验证后,筛选出一阶偏度特征和体积2个特征构建影像组学模型。训练集、测试集和外部验证集的影像组学预测模型ROC曲线的AUC、灵敏度、特异度、阳性预测值和阴性预测值分别为0.920、97.1%、85.7%、91.9%、94.7%;0.885、80.0%、88.9%、92.3%、72.7%;0.875、87.5%、88.9%、93.3%、80.0%。DCA曲线显示,当风险阈值范围为0%~82%时,采用影像组学模型预测LARC患者为病理完全缓解(pCR)的获益大于将所有患者都视为pCR或者无病理完全缓解(npCR)。结论:基于MRI影像组学构建的dMMR/MSI-H型局部进展期直肠癌PD-1/PD-L1抑制剂联合全程新辅助放化疗疗效预测模型,有较大潜力为不同基因分型的直肠癌患者制定个体化治疗策略提供量化依据。

^1H MRS在足月新生儿缺氧缺血性脑病中的应用

目的 通过探讨氢质子磁共振波谱与足月新生儿缺氧缺血性脑病代谢变化的关系,以评估氢质子磁共振波谱在诊断足月新生儿缺氧缺血性脑病及预后的作用.方法 研究对象为30例在临床诊断为新生儿缺氧缺血性脑病的足月新生儿与7例足月正常对照儿.所有研究对象于出生13天内进行头颅氢质子磁共振波谱检查,测量右侧基底节和右侧额叶代谢产物波峰下面积值,同时记录研究对象的胎龄、性别、分娩方式、出生体重、头颅氢质子磁共振波谱检查时的日龄、新生儿缺氧缺血性脑病临床分度等资料,于其生后第3天、第7天、第14天、第28天进行新生儿行为神经评分,并对上述资料进行统计学分析.结果 ①新生儿缺氧缺血性脑病组与对照组比较,右侧基底节和右侧额叶乳酸/肌酸、N-乙酰天门冬氨酸/肌酸、谷氨酸盐和谷氨酰胺/肌酸的比值均有统计学意义（均P〈0.05）;而右侧基底节和右侧额叶肌醇/肌酸、胆碱/肌酸的比值均无统计学意义（均P〉0.05）;②新生儿缺氧缺血性脑病轻度与中重度比较,右侧基底节和右侧额叶乳酸/肌酸、N-乙酰天门冬氨酸/肌酸、谷氨酸盐和谷氨酰胺/肌酸的比值均有统计学意义（均P〈0.05）;③新生儿缺氧缺血性脑病组右侧基底节和右侧额叶乳酸/肌酸、N-乙酰天门冬氨酸/肌酸、谷氨酸盐和谷氨酰胺/肌酸的比值与临床分度有显著相关性（均P〈0.01）;④新生儿缺氧缺血性脑病组右侧基底节和右侧额叶乳酸/肌酸、N-乙酰天门冬氨酸/肌酸、谷氨酸盐和谷氨酰胺/肌酸的比值与患儿第14天新生儿行为神经评分具有显著相关性（均P〈0.01）.结论 氢质子磁共振波谱对新生儿缺氧缺血性脑病的临床诊断及短期预后评估具有重要临床意义,值得深入研究及推广.

联合应用MRDCE-TIC与^1H-MRS对乳腺肿瘤的诊断价值

目的探讨单独应用MR动态增强扫描（DCE）时间-信号强度曲线（TIC）、氢质子磁共振波谱（^1H-MRS）与二者联合应用对乳腺肿瘤的诊断价值.方法回顾性分析41例乳腺肿块（恶性肿瘤23例,良性肿瘤18例）的DCE-TIC和^1H-MRS表现,并与手术或穿刺后病理结果对比.所有患者均为女性,年龄17-69岁,平均（41.0±14.7）岁,均应用GE公司的1.5TSigna HDxt扫描仪,8通道乳腺专用线圈,扫描序列包括：轴位STIR、TIWI、乳腺容积动态增强序列（VIBRANT）和1 H-MRS扫描,评价单独应用DCE-MRI时间-信号强度曲线（TIC）、磁共振波谱（^1H-MRS）及二者联合应用对诊断乳腺肿瘤的诊断能力.结果 ①以DCE-TIC类型诊断乳腺肿瘤的敏感度为82.6%,特异度为77.8%,准确度为80.5%;②以^1H-MRS出现Cho峰诊断乳腺肿瘤的敏感度为70.0%,特异度为83.3%,准确度为75.6%;③将TIC与1 H-MRS Cho峰结合,诊断的敏感度为78.0%,特异度为88.9%,准确率为82.9%.结论 DCE-MRI TIC诊断乳腺肿瘤的特异度较低,联合应用DCE-TIC和^1H-MRS可提高乳腺肿瘤性病变的诊断特异度、准确度.

依达拉奉对急性脑梗死患者^1H MRS的影响

目的观察依达拉奉对急性脑梗死患者磁共振氢质子波谱(1H magnetic resonance spectroscopy,1H MRS)的影响,评价依达拉奉治疗急性脑梗死的疗效。方法选择发病24h内的急性脑梗死患者66例,随机分为依达拉奉组(35例)及对照组(31例)。对2组治疗前及4周后美国国立卫生研究院脑卒中量表评分(NIHSS评分)、N-乙酰天冬氨酸(NAA),N-乙酰天冬氨酸与肌酸(Cr)比值(NAA/Cr)进行比较。结果4周后依达拉奉组NIHSS评分(5.71±1.74)较对照组(7.26±2.87)降低明显,差异有统计学意义(P<0.05)。4周后NAA、NAA/Cr值对照组(514±118、1.67±0.23)和依达拉奉组(613±169、1.82±0.28)均较治疗前(对照组345±108、1.34±0.18;治疗组336±115、1.32±0.19)升高,但依达拉奉组升高明显,差异有统计学意义(P<0.05)。结论依达拉奉是一种有效的治疗急性脑梗死的神经保护剂。

用^(1)H定量核磁共振法同时确定成盐化合物的质量分数和各组分的比例

^(1)H定量核磁共振(^(1)H quantitative nuclear magnetic resonance,^(1)H qNMR)方法具有操作简便、实验快速等优点.本文通过该方法可准确测定富马酸丙酚替诺福韦在样品中的含量,并给出丙酚替诺福韦和富马酸的比例,结果与其他分析测试所得结果相符.该方法以氘代二甲基亚砜(DMSO-d^(6))为溶剂,采集待测样品的核磁共振氢谱,对比丙酚替诺福韦定量峰、富马酸定量峰与内标物响应峰面积,分别计算丙酚替诺福韦和富马酸的质量分数.富马酸丙酚替诺福韦和富马酸与内标物的质量比值在0.91~1.24范围内线性关系良好,^(1)H qNMR法测得二者质量分数分别为100.06%和10.90%,与质量平衡法测得的结果基本一致.本研究建立的核磁共振定量方法不仅可准确、快速地测定丙酚替诺福韦和富马酸这2种成分的质量分数和比例,还为多组分、成盐的化学原料药的比例确定、绝对含量测定提供参考.

^1H—MRS对碘异常引起脑损伤的诊断价值

目的探讨氢质子磁共振波谱分析(1H-MRS)在碘异常引起脑损伤病变中的应用价值。方法收集临床诊断碘异常引起脑损伤的病例28例,其中低碘组16例,高碘组12例。使用西门子1.5 T MRI,多体素相位矩阵扫描。检测低碘组和高碘组病人海马区与正常参照区域的代谢物浓度,利用SPSS12.0分析各种代谢物的变化。结果1H-MRS示低碘组胆碱降低、γ-氨基丁酸、N-乙酰天门冬氨酸减少;高碘组胆碱增加、谷氨酸升高,γ-氨基丁酸、N-乙酰天门冬氨酸减少。结论1H-MRS在碘异常引起脑损伤病变定性诊断中有重要的临床价值。