Application Progress of Intravoxel Incoherent Motion Diffusion Weighted Magnetic Resonance Imaging in Pancreatic Cancer

Intravoxel incoherent motion imaging (IVIM), on the traditional diffusion weighted imaging (DWI) technology, uses the biexponential model and adopts the multi-b-value analysis to obtain the perfusion information of water molecule diffusion and microcirculation without the use of contrast agent. It is more and more used in pancreatic diseases, which is of great significance for the diagnosis and identification of pancreatic cancer. This article will review the principles of IVIM imaging and its application in pancreatic diseases, especially in pancreatic cancer diagnosis, the prediction of pathological grade of pancreatic ductal adenocarcinoma, the judgment of lymph node metastasis, and differentiation of pathological classification.

Intravoxel incoherent motion magnetic resonance imaging for diagnosis of cervical cancer and evaluation of response of uterine cervical cancer to radiochemotherapy: A pilot study

Objective The aim of this study was to investigate the ability of intravoxel incoherent motion(IVIM) diffusion-weighted magnetic resonance imaging(MRI) to diagnose cervical cancer and to evaluate the response of uterine cervical cancer to radiochemotherapy(CRT).Methods This prospective study was approved by the institutional review board, and informed consent was obtained from all patients. A total of 23 patients with primary cervical cancer who were undergoing CRT and 16 age-matched healthy subjects were prospectively recruited for IVIM(b = 0–800 s/mm2) and standard pelvic MRI. Bi-exponential analysis was performed to derive f(perfusion fraction), D*(pseudo-diffusion coefficient), and D(true molecular diffusion coefficient) in cervical cancer(n = 23) and the normal cervix(n = 16). The apparent diffusion coefficient(standard ADC) was calculated. The independent-samples t-test and paired-samples t-test were used for comparisons.Results Pre-treatment cervical cancer had the lowest standard ADC(1.15 ± 0.13 × 10-3 mm2/s) and D(0.89 ± 0.10 × 10-3 mm2/s) values, and these were significantly different from the normal cervix and posttreatment cervical cancer(P = 0.00). The f(16.67 ± 5.85%) was lowest in pre-treatment cervical cancer and was significantly different from the normal cervix and post-treatment cervical cancer(p = 0.012 and 0.00, respectively). No difference was observed in D*.Conclusion IVIM is potentially promising for differentiating between the normal cervix and cervical cancer because pre-treated cervical cancer has low perfusion and diffusion IVIM characteristics. Further, the standard ADC, D, and f of cervical cancer showed a tendency to normalize after CRT; thus, IVIM may be useful for monitoring the response to CRT in cervical cancer.

Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

Diffusion-weighted magnetic resonance imaging(DWMRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer.It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DWMRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the nonmono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging(DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.

Value of multiple models of diffusion-weighted imaging to predict hepatic lymph node metastases in colorectal liver metastases patients

BACKGROUND About 10%-31% of colorectal liver metastases(CRLM)patients would concomitantly show hepatic lymph node metastases(LNM),which was considered as sign of poor biological behavior and a relative contraindication for liver resection.Up to now,there’s still lack of reliable preoperative methods to assess the status of hepatic lymph nodes in patients with CRLM,except for pathology examination of lymph node after resection.AIM To compare the ability of mono-exponential,bi-exponential,and stretchedexponential diffusion-weighted imaging(DWI)models in distinguishing between benign and malignant hepatic lymph nodes in patients with CRLM who received neoadjuvant chemotherapy prior to surgery.METHODS In this retrospective study,97 CRLM patients with pathologically confirmed hepatic lymph node status underwent magnetic resonance imaging,including DWI with ten b values before and after chemotherapy.Various parameters,such as the apparent diffusion coefficient from the mono-exponential model,and the true diffusion coefficient,the pseudo-diffusion coefficient,and the perfusion fraction derived from the intravoxel incoherent motion model,along with distributed diffusion coefficient(DDC)andαfrom the stretched-exponential model(SEM),were measured.The parameters before and after chemotherapy were compared between positive and negative hepatic lymph node groups.A nomogram was constructed to predict the hepatic lymph node status.The reliability and agreement of the measurements were assessed using the coefficient of variation and intraclass correlation coefficient.RESULTS Multivariate analysis revealed that the pre-treatment DDC value and the short diameter of the largest lymph node after treatment were independent predictors of metastatic hepatic lymph nodes.A nomogram combining these two factors demonstrated excellent performance in distinguishing between benign and malignant lymph nodes in CRLM patients,with an area under the curve of 0.873.Furthermore,parameters from SEM showed substantial repeatability.CONCLUSION The developed nomogram,incorporating the pre-treatment DDC and the short axis of the largest lymph node,can be used to predict the presence of hepatic LNM in CRLM patients undergoing chemotherapy before surgery.This nomogram was proven to be more valuable,exhibiting superior diagnostic performance compared to quantitative parameters derived from multiple b values of DWI.The nomogram can serve as a preoperative assessment tool for determining the status of hepatic lymph nodes and aiding in the decision-making process for surgical treatment in CRLM patients.

Chemotherapy response evaluation in a mouse model of gastric cancer using intravoxel incoherent motion diffusionweighted MRI and histopathology

AIM To determine the role of intravoxel incoherent motion(IVIM) diffusion-weighted(DW) magnetic resonance imaging(MRI) using a bi-exponential model in chemotherapy response evaluation in a gastric cancer mouse model.METHODS Mice bearing MKN-45 human gastric adenocarcinoma xenografts were divided into four treated groups(TG1, 2, 3 and 4, n = 5 in each group) which received Fluorouracil and Calcium Folinate and a control group(CG, n = 7). DW-MRI scans with 14 b-values(0-1500 s/mm2) were performed before and after treatment on days 3, 7, 14 and 21. Fast diffusion component(presumably pseudo-perfusion) parameters including the fast diffusion coefficient(D*) and fraction volume(f p), slow diffusion coefficient(D) and the conventional apparent diffusion coefficients(ADC) were calculated by fitting the IVIM model to the measured DW signals. The median changes from the baseline to each posttreatment time point for each measurement(ΔADC, ΔD* and Δf p) were calculated. The differences in the median changes between the two groups were compared using the mixed linear regression model by the restricted maximum likelihood method shown as z values. Histopathological analyses including Ki-67, CD31, TUNEL and H&E were conducted in conjunction with the MRI scans. The median percentage changes were compared with the histopathological analyses between the pre-and post-treatment for each measurement.RESULTS Compared with the control group, D* in the treated group decreased significantly(ΔD*treated% =-30%,-34% and-20%, with z =-5.40,-4.18 and-1.95. P = 0.0001, 0.0001 and 0.0244) and f p increased significantly(Δfptreated% = 93%, 113% and 181%, with z = 4.63, 5.52, and 2.12, P = 0.001, 0.0001 and 0.0336) on day 3, 7 and 14, respectively. Increases in ADC in the treated group were higher than those in the control group on days 3 and 14(z = 2.44 and 2.40, P = 0.0147 and P = 0.0164). CONCLUSION Fast diffusion measurements derived from the biexponential IVIM model may be more sensitive imaging biomarkers than ADC to assess chemotherapy response in gastric adenocarcinoma.

Assessing the Early Response of Advanced Cervical Cancer to Neoadjuvant Chemotherapy Using Intravoxel Incoherent Motion Diffusion-weighted Magnetic Resonance Imaging： A Pilot Study

Background： Diffusion-weighted imaging （DWI） with the intravoxel incoherent motion （IVIM） model has shown promising results for providing both diffusion and perfusion intbrmation in cervical cancer; however, its use to predict and monitor the efficacy ofneoadjuvant chemotherapy （NACT） in cervical cancer is relatively rare. The study aimed to evaluate the use of DWl with 1VIM and monoexponential models to predict and monitor the efficacy of NACT in cervical cancer. Methods： Forty-two patients with primary cervical cancer underwent magnetic resonance exams at 3 time points （pre-NACT, 3 weeks after the first NACT cycle, and 3 weeks after the second NACT cycle）. The response to treatment was determined according to the response evaluation criteria in solid tumors 3 weeks after the second NACT treatment, and the subjects were classified as two groups： responders and nonresponders groups. The apparent diffusion coefficient （ADC）, true diffusion coefficient （D）, perfusion-related pseudo-diffusion coefficient （D＊）, and perfusion fraction （f） values were determined. The differences in IVlM-derived variables and ADC between the different groups at the different time points were calculated using an independent samples t-test. Results： The D and ADC values were all significantly higher for the responders than tbr the nonresponders at all 3 time points, but no significant differences were observed in the D＊ and fvalues. An analysis of the receiver operating characteristic （ROC） curves indicated that a D value threshold 〈0.93 × 10 3 mm2/s and an ADC threshold 〈1.11× 10 3 mm2/s could differentiate responders from nonresponders at pre-NACT time point, yielding area under the curve （AUC） of which were 0.771 and 0.806, respectively. The ROC indicated that the AUCs of D and ADC at the 3 weeks after the first NACT cycle and 3 weeks after the second NACT cycle were 0.823, 0.763, and 0.787, 0.794, respectively. The AUC values of D and ADC at these 3 time points were not significantly different （P = 0.641, 0.512, and 0.547, respectively）. Conclusions： D and ADC values may be useful for predicting and monitoring the efficacy of NACT in cervical cancer. An IVIM model may be equal to monoexponential model in predicting and monitoring the efficacy of NACT in cervical cancer.

Initial study of biexponential model of intravoxel incoherent motion magnetic resonance imaging in evaluation of the liver fibrosis

Background The diagnosis of liver fibrosis is a difficult task at any time using conventional clinical imaging.Intravoxel incoherent motion （IVIM） can be used to investigate both diffusion and perfusion changes in tissues.This study was designed to determine the value of IVIM in the diagnosis and staging of liver fibrosis.Methods IVIM examinations were performed on a GE 3.0T MR scanner in 25 patients with liver fibrosis and 25 healthy volunteers as the control group.Patients with liver fibrosis diagnosis were confirmed by pathology and staged on a scale of F0-4.The standard ADC values and the values of a biexponential model （slow ADC （Dslow）,fast ADC （Dfast） and fraction of fast ADC （FF）） were measured in three liver regions per person.The mean standard ADC values,Dslow values,Dfast values and FF values from the study group were compared among the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Receiver Operating Characteristic （ROC） curves and independent-samples t-tests were used to calculate the mean standard ADC values,Dslow values,Dfast values and FF values from the study group and the control group.Spearman rho correlation analysis was used for the stage of liver fibrosis.The liver fibrosis stages between the groups F0-1 and F2-4,the groups F0-2 and F3-4 were compared.Results Among the liver fibrosis,there was no significant difference in the mean standard ADC values,Dslow values,Dfast values,and FF values obtained from the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Using ROC analysis,the Area Under the Curve （AUC） values of standard ADC,Dslow,Dfast,FF were all between 0.7 to 0.9.The mean standard ADC values,Dslow values,Dfast values and FF values of the liver in the study group were significantly lower than the values in the control group （P ＜0.05）.As the stage of the fibrosis increased,the values decreased by Spearman rho correlation analysis.The mean values （standard ADC,Dslow,Dfast,and FF） of liver fibrosis stages between the groups F0-1 and F2-4,the groups F0-2 and F3-4 showed significant differences （P＜0.05）.Conclusions IVIM can reflect the conditions of perfusion and diffusion in liver fibrosis and thus distinguish between normal liver and liver fibrosis.The IVIM technique may serve as a valuable tool for detecting and characterizing liver fibrosis,and monitoring its progression in a noninvasive manner.

Value of intravoxel incoherent motion in detecting and staging liver fibrosis: A meta-analysis

BACKGROUND Liver fibrosis(LF) is a common pathological feature of all chronic liver diseases.With the accumulation of extracellular matrix in the fibrotic liver, true molecular water diffusion and perfusion-related diffusion are restricted. Intravoxel incoherent motion(IVIM) can capture the information on tissue diffusivity and microcapillary perfusion separately and reflect the fibrotic severity with diffusion coefficients.AIM To investigate the diagnostic performance of IVIM in detecting and staging LF with histology as a reference standard.METHODS A comprehensive literature search was conducted to identify studies on the diagnostic accuracy of IVIM for assessment of histologically proven LF. The stages of LF were classified as F0(no fibrosis), F1(portal fibrosis without septa),F2(periportal fibrosis with few septa), F3(septal fibrosis), and F4(cirrhosis)according to histopathological findings. Data were extracted to calculate the pooled sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio, as well as the area under the summary receiver operating characteristic curve(AUC) in each group.RESULTS A total of 12 studies with 923 subjects were included in this meta-analysis with 5 studies(n = 465) for LF ≥ F1, 9 studies(n = 757) for LF ≥ F2, 4 studies(n = 413) for LF ≥ F3, and 6 studies(n = 562) for LF = F4. The pooled sensitivity and specificity were estimated to be 0.78(95% confidence interval: 0.73-0.82) and 0.81(0.74-0.86)for LF ≥ F1 detection with IVIM;0.82(0.79-0.86) and 0.80(0.75-0.84) for staging F2 fibrosis;0.85(0.79-0.90) and 0.83(0.77-0.87) for staging F3 fibrosis, and 0.90(0.84-0.94) and 0.75(0.70-0.79) for detecting F4 cirrhosis, respectively. The AUCs for LF≥ F1, F2, F3, F4 detection were 0.862(0.811-0.914), 0.883(0.856-0.909), 0.886(0.865-0.907), and 0.899(0.866-0.932), respectively. Moderate to substantial heterogeneity was observed with inconsistency index(I2) ranging from 0% to 77.9%. No publication bias was detected.CONCLUSION IVIM is a noninvasive tool with good diagnostic performance in detecting and staging LF. Optimized and standardized IVIM protocols are needed to further improve its diagnostic accuracy in clinical practice.

Advanced imaging techniques in the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the major causes of morbidity and mortality in patients with chronic liver disease. Transarterial chemoembolization(TACE) can significantly improve the survival rate of patients with HCC and is the first treatment choice for patients who are not suitable for surgical resections. The evaluation of the response to TACE treatment affects not only the assessment of the therapy efficacy but also the development of the next step in the treatment plan. The use of imaging to examine changes in tumor volume to assess the response of solid tumors to treatment has been controversial. In recent years, the emergence of new imaging technology has made it possible to observe the response of tumors to treatment prior to any morphological changes. In this article, the advances in studies reporting the use of computed tomography perfusion imaging, diffusionweighted magnetic resonance imaging(MRI), intravoxel incoherent motion, diffusion kurtosis imaging, magnetic resonance spectroscopy, magnetic resonance perfusionweighted imaging, blood oxygen level-dependent MRI, positron emission tomography(PET)/computed tomography and PET/MRI to assess the TACE treatment response are reviewed.

基于扩散加权成像及MRI对四肢软组织肿瘤的诊断价值

目的 探讨基于扩散加权成像及MRI对四肢软组织肿瘤(soft tissue tumors,STTs)的诊断价值。方法 选取本院经病理证实的四肢STTs患者74例,其中良性46例(良性组)、恶性28例(恶性组),均行常规MRI、DWI、IVIM及DKI扫描,分析两组常规MRI检查征象及诸参数差异,包括表观扩散系数(ADC)、真实扩散系数(D)、灌注相关扩散系数(D~*)、灌注分数(f)、平均扩散峰度值(MK)和平均扩散率(MD);运用ROC曲线分析其诊断效能。结果 恶性组肿瘤边界多不清且呈浸润性生长,以团块状为主,瘤周水肿、筋膜尾征多见,50.0%瘤内可见分隔,两组间差异有统计学意义(P<0.05)。恶性组ADC、D和MD值小于良性组,而MK值高于良性组,差异具有统计学意义(P<0.05)。D~*和f值两组差异无统计学意义(P>0.05)。ADC、D、MD、MK值在鉴别四肢STTs良恶性方面均具有一定诊断效能:AUC≥0.688,敏感度≥63.0%,特异度≥67.9%,准确度≥64.9%,其中MD值的诊断效能、特异度最高。ADC+D+MD+MK联合后,AUC为0.887,诊断效能均高于单一参数(Z=1.978~3.101;P<0.05),敏感度为76.1%,特异度为92.9%,准确度78.4%。结论 基于扩散加权成像及MRI对四肢STTs良恶性有较好的判断价值,值得临床推广。

动态增强磁共振联合体素内不相干运动成像对三阴性乳腺癌的诊断价值

目的 探讨动态增强磁共振成像(DCE-MRI)联合体素内不相干运动(IVIM)对三阴性(TNBC)及非三阴性乳腺癌的鉴别诊断价值。方法 回顾性分析本院经病理证实的乳腺癌患者180例,TNBC组49例,非TNBC组131例,所有患者均行DCE-MRI及IVIM及检查。分析两组间的临床病理资料、常规MRI征象和IVIM、 DCE-MRI模型诸定量参数。结果 TNBC组的病灶不规则形较非TNBC组少见,强化多不均匀,环形强化占比较大,两组间差异有统计学意义(P=0.001,P=0.007)。TNBC组的Ve值小于非TNBC组(P<0.001),呈低度负相关(r=-0.439,P<0.001);TNBC组的D、f、K_(ep)值高于非TNBC组(P=0.002~0.016),呈低度正相关(r=0.186~0.257,P<0.05)。D^(*)、K^(trans)值在两组间差异不具有统计学差异(P>0.05)。D≥0.86×10^(-3)mm^(2)/s、f≥38.1%、K_(ep)≥0.359/min、V_(e)≤0.589为鉴别TNBC和非TNBC的独立影响因素,其中Ve值的AUC为0.784,大于其他定量参数(Z=2.201~2.752,P=0.006~0.028)。DC E-MRI模型AUC为0.817,大于IVIM模型(AUC=0.657)和常规MRI模型(AUC=0.689),差异具有统计学意义(Z=2.657;P=0.008;Z=2.516,P=0.012)。联合DCE-MRI、IVIM模型,AUC为0.862,诊断效能均高于单一模型(Z=2.194~4.649,P<0.05),敏感度为83.7%,特异度为74.8%,准确度为80.0%。结论 DCE-MRI、IVIM模型可用于TNBC的诊断,其中DCE-MRI模型的Ve值诊断效能最高,IVIM联合DC E-M RI模型对鉴别TN BC及非TN BC的诊断效能优于单一模型。

DCE-MRI和IVIM-DWI评估直肠癌微血管含量的比较研究

目的:探讨动态对比增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)和体素内不相干运动弥散加权成像(intravoxel incoherent motion diffusion-weighted imaging,IVIM-DWI)在评估直肠癌微血管含量中的差异。方法:研究2019年12月—2022年12月上海中医药大学附属曙光医院经病理学检查诊断为直肠腺癌并行IVIMDWI和DCE-MRI扫描的患者23例。Tofts模型计算DCE-MRI参数为容积分数(volume fraction,V_(e))、容量转移常数(space transport coefficient,K^(trans))和速率常数(rate constant,K_(ep))。IVIM-DWI参数:单纯弥散系数(simple diffusion coefficient,D),灌注相关弥散系数(perfusion related diffusion coefficient,D^(*)),灌注分数(perfusion fraction,f),通过计算双指数模型得到。对与直肠癌微血管含量相关的DCE-MRI和IVIM-DWI定量参数进行分析比较。结果:不同病理学分级的直肠癌K^(trans)和D差异有统计学意义(F=9.159,P=0.002;F=5.106,P=0.016)。在评估直肠癌病理学分级时,K^(trans)优于D。灌注参数K^(trans),K_(ep)和D^(*)与直肠癌微血管含量呈显著正相关(r=0.734,P<0.001;r=0.617,P=0.002;r=0.456,P=0.029)。其中DCE-MRI定量参数评估直肠癌微血管含量优于IVIM-DWI定量参数。结论:与IVIM-DWI相比,DCE-MRI评价直肠癌分化程度和微循状态方面效能更佳。但是考虑到IVIM-DWI不需要注射对比剂,IVIM-DWI仍然可以被推荐用于直肠癌分化程度和微循环状态。

多参数MRI联合临床危险因素术前预测直肠癌淋巴血管间隙侵犯的应用价值

目的探讨多参数MRI联合临床危险因素术前预测直肠癌淋巴血管间隙侵犯(LSVI)的价值。方法回顾性分析池州市人民医院2022年4月至2023年11月经术后病理证实的38例直肠癌患者的临床及影像学资料,所有患者均行常规MRI、合成MRI及IVIM-DWI序列扫描。依据术后病理结果分为LVSI阳性组(n=14)和LVSI阴性组(n=24)。采用单因素和多因素logistic回归分析LVSI阳性组和LVSI阴性组的临床资料,分析LVSI的临床危险因素;比较两组患者合成MRI(T1值、T2值、PD值)及IVIM-DWI参数(D值、D*值、f值),采用受试者工作特征(ROC)曲线评价各定量参数预测模型及联合临床危险因素预测模型的诊断效能。结果合成MRI的T2值及IVIM-DWI的D值、f值在直肠癌LVSI阳性组和阴性组中比较差异具有统计学意义(P<0.05)。术前CEA(OR=10.818,95%CI:1.391~84.124)及临床N分期(OR=11.852,95%CI:1.534~91.552)是直肠癌LVSI的独立危险因素(P<0.05)。单独的T2值、D值、f值及三者联合的曲线下面积(AUC)分别为0.801、0.747、0.766、0.807,联合临床危险因素的预测模型效能最高(AUC=0.845),灵敏度为78.58%,特异度为100%。结论多参数MRI术前可有效预测直肠癌LVSI的状态,结合临床危险因素的联合预测模型可进一步提升预测效能,有助于临床医师制定个性化直肠癌治疗方案。

腹部DCE-MRI联合IVIM诊断子宫内膜病变的临床价值

目的探究腹部磁共振成像动态对比增强成像(DCE-MRI)联合体素内不相干运动扩散加权成像(IVIM)诊断子宫内膜病变的临床价值。方法选取2022年1月至2023年2月我院行MRI检查的子宫内膜病变患者82例,以病理结果为“金标准”,将患者分为良性组(49例)和恶性组(33例),比较两组DCEMRI、IVIM参数差异,绘制ROC曲线分析DCE-MRI联合IVIM检测子宫内膜病变的诊断价值。结果良性组体积转运常数(Ktrans)、速率转运常数(Kep)、体积分数(Ve)值低于恶性组(P<0.05)。良性组慢速表观扩散系数(ADC-slow)、灌注分数(f)、水分子扩散分布指数(DDC)、扩散异质性指数(α)值高于恶性组,快速表观扩散系数(ADC-fast)值低于恶性组(P<0.05)。ROC曲线分析显示:当Ktrans、Ke p、Ve、ADCslow、ADC-fast、f、DDC、αAUC分别为0.812、0.762、0.736、0.726、0.666、0.706、0.686、0.777时,约登指数最大,其截断值分别为0.45、0.86、0.51、0.47、12.69、0.37、1.02、0.66时,联合诊断AUC为0.894(95%CI:0.812~0.975)、灵敏度84.8%、特异度93.9%、阳性预测值93.4%、阴性预测值86.2%均高于各参数单项检测(P<0.05),诊断效能最佳。结论腹部DCE-MRI联合IVIM可提高子宫内膜病变的诊断准确性,具有较高临床价值。

IVIM联合DKI成像技术在肝纤维化分级中的应用价值

目的探讨体素内不相干运动成像(IVIM)联合扩散峰度成像(DKI)成像技术在肝纤维化分级中的应用价值。方法选取我院2021年10月至2023年6月期间80例肝纤维化患者(F1期29例、F2期27例、F3-4期24例),纳入观察组,同时期健康体检者50例,纳入对照组,均行肝脏MRI检查,获取IVIM、DKI参数。比较观察组与对照组以及观察组不同肝纤维化分级患者的IVIM、DKI参数,分析各参数与肝纤维化分级之间的相关性,分析肝纤维化分级≥F2期的独立相关因素,构建预测模型,采用受试者工作特征(ROC)曲线分析模型的预测价值。结果观察组IVIM参数ADC、D、D、f值及DKI参数MD值均小于对照组(P<0.05),DKI参数MK、K值均大于对照组(P<0.05);F3-4期患者IVIM参数ADC、D、D、f值及DKI参数MD值均小于F1期、F2期患者(P<0.05),DKI参数MK、K值均大于F1期、F2期患者(P<0.05);Spearman相关性分析显示,肝纤维化分级与ADC、D、D、f、MD值均呈负相关(P<0.05),与MK、K值均呈正相关(P<0.05);Logistic多因素回归分析显示,ADC、D、D、f、MD值均为肝纤维化分级≥F2期的独立相关因素(P<0.05);构建肝纤维化分级≥F2期的预测模型:Y=-4.512-2.819 X1-2.412 X2-1.763 X3-1.338 X4-1.582 X5,ROC曲线显示该模型预测肝纤维化分级≥F2期的ROC曲线下面积为0.926(95%CI=0.881-0.970,P<0.001),最佳截断值对应的敏感度、特异度、约登指数分别为89.20%、87.80%、0.770,拟合优度检验显示χ^(2)=8.205,P=0.084,调整后的R2=0.823。结论IVIM与DKI在肝纤维化分级中具有一定应用价值,结合IVIM与DKI参数所构建的预测模型对于肝纤维化分级≥F2期的患者具有较高的预测精度。

DWI结合IVIM评估中青年脑梗死病情程度及预测溶栓治疗后出血转化的价值

目的 探究磁共振弥散加权成像(diffusion weighted imaging, DWI)结合体素内不相干运动(introvoxel incoherent motion, IVIM)评估中青年脑梗死病情程度及预测溶栓治疗后出血转化(hemorrhagic transformation, HT)的价值,以期为临床早期针对性制定干预方案提供参考。方法 回顾性选取中青年急性缺血性脑卒中患者96例,入院时均行DWI、IVIM检查,获取健侧和患侧表观扩散系数(apparent diffusion coefficient, ADC)、灌注分数(perfusion fraction, f)、快速表观扩散系数(pseudo-diffusion coefficient, D^(*))、慢速表观扩散系数(diffusion coefficient of pure diffusion, D),并对各参数进行标准化处理。比较不同病情程度患者rADC、rf、rD^(*)、rD,分析各参数与中青年脑梗死病情程度的相关性。静脉溶栓治疗后比较发生与未发生HT患者入院时rADC、rf、rD^(*)、rD及HT相关生物学指标[胱抑素C(cystatin C,Cys-C)、纤维胶凝蛋白3(fibrinolytic protein 3,Ficolin-3)、补体C1q/肿瘤坏死因子相关蛋白3(complement C1q/tumor necrosis faction-associated protein-3,CTRP-3)]水平,采用ROC曲线评价各参数预测中青年脑梗死溶栓治疗后发生HT的价值。结果 中青年脑梗死患者入院时患侧ADC、f、D^(*)、D均低于健侧(P<0.05)。重度患者入院时rADC、rf、rD^(*)、rD均低于中度、轻度患者,中度患者入院时rADC、rf、rD^(*)、rD均低于轻度患者(P<0.05)。入院时rADC、rf、rD^(*)、rD与中青年AIS病情程度呈负相关(P<0.05)。发生HT患者rADC、rf、rD^(*)、rD及血清Ficolin-3、CTRP-3水平均低于未发生HT患者低,Cys-C水平高于未发生HT患者(P<0.05)。发生HT患者入院时rADC、rf、rD^(*)、rD与血清Cys-C水平呈负相关,与血清Ficolin-3、CTRP-3水平呈正相关(P<0.05)。入院时rADC、rf、rD^(*)、rD联合预测中青年AIS患者溶栓治疗后发生HT的AUC为0.943,大于血清Cys-C、Ficolin-3、CTRP-3联合预测的AUC(Z=0.195,P=0.043)。结论 DWI结合IVIM可用于中青年脑梗死病情程度评估,为临床预测溶栓治疗后HT的发生提供参考依据,以针对性展开后续治疗,降低HT发生风险。

肾脏IVIM最佳水化状态及稳定性、可重复性研究

目的探讨行肾脏体素内不相干运动成像(intravoxel incoherent motion,IVIM)检查的最佳水化状态,并分析检查结果的稳定性和可重复性。方法选取健康成年人志愿者40例,每例志愿者均分别在禁饮食12 h、禁饮食4 h及水利尿三种状态下行肾脏IVIM检查;其中36例志愿者在间隔半年后,在禁饮食4 h状态下重复行肾脏IVIM检查。结果三种不同水化状态下,肾皮质(F=1.870,P=0.163)及髓质(F=0.579,P=0.562)D值间的差异无统计学意义,肾皮质(F=0.188,P=0.829)及髓质(F=0.008,P=0.992)D*值间的差异均无统计学意义,肾皮质(F=1.317,P=0.216)及髓质(F=0.336,P=0.715)f值间的差异均无统计学意义。结论水化状态不影响肾脏IVIM的检查结果,肾脏IVIM检查有很高的稳定性和可重复性;肾脏IVIM检查可以监测正常肾脏的微循环状态及血流灌注状态。

IVIM全容积定量参数与直肠腺癌神经脉管侵犯、MSI状态及Ki-67指数的相关性研究

目的探讨体素内不相干运动(intravoxel incoherent motion,IVIM)全肿瘤容积参数与直肠腺癌患者神经侵犯(perineural invasion,PNI)、脉管侵犯(lymphovascular invasion,LVI)、微卫星不稳定性(microsatellite instability,MSI)状态及Ki-67指数的相关性。材料与方法回顾性分析136例直肠腺癌患者的影像资料和临床资料,测量病灶IVIM全容积参数包括真实扩散系数(D)、伪扩散系数(D*)及灌注分数(f)。根据病理报告中的LVI状态、PNI状态、MSI及Ki-67指数进行分组,采用独立样本t检验或Mann-Whitney U检验分析各定量参数与肿瘤病理学特征的关系。结果直肠腺癌PNI阴性组D值[(1.174±0.164)×10^(-3) mm^(2)/s]显著低于阳性组[(1.270±0.206)×10^(-3) mm^(2)/s](t=-3.033,P=0.003),LVI阴性组f值0.172(0.158,0.193)显著低于阳性组0.188(0.168,0.237)(Z=-2.435,P=0.015),Ki-67低表达组f值(0.175±0.035)显著低于高表达组(0.188±0.038)(t=-2.097,P=0.038),MSI高组和MSI低组的D、D*、f值差异无统计学意义(P>0.05)。结论IVIM全容积定量参数能够在一定程度上反映直肠腺癌的病理学特征,可作为术前评估直肠腺癌生物学行为的重要影像学指标。

数字乳腺断层合成摄影和对比增强乳腺 X 线摄影检查对乳腺 BI-RADS 4类病变的诊断价值

目的探讨评估体素内不相干运动(intravoxel incoherent motion,IVIM)联合扩散峰度成像(diffusional kurtosis imaging,DKI)预测乳腺癌腋窝淋巴结(ALN)转移的价值。方法选取经病理证实的157例乳腺癌患者,于术前行IVIM、DKI检查。对比两组间IVIM及DKI定量参数的差异性。将157例患者分为ALN转移组71例和无转移组86例,采用受试者工作特征曲线(receiver operating characteristic curve,ROC)评估的诊断效能,曲线下面积(area under curve,AUC)的差异性分析采用Delong检验。结果乳腺癌ALN转移组与无转移组间患者年龄、病灶大小、病灶边缘、真性扩散系数(D)值、灌注相关扩散系数(D*)值、灌注分数(f)值、扩散峰度(MK)值、平均扩散率(MD)值比较差异有统计学意义(P<0.05)。Logistic回归分析表明,D值(OR=0.001,P<0.001)、D*值(OR=1.108,P=0.001)、f值(OR=1.326,P<0.001)、MD值(OR=0.001,P<0.001)及MK值(OR=588.98,P<0.001)是预测LAN转移的独立影响因素,其中D值的诊断效能最大,当D≤0.74×10^(-3)mm^(2)/s时AUC为0.886。IVIM联合DKI对预测乳腺癌ALN转移的效能最大,AUC为0.982,准确度、敏感度及特异度分别为90.14%、87.32%、84.51%。结论IVIM和DKI定量参数可用于预测乳腺癌ALN转移,其中D值诊断效能最高。IVIM联合DKI在乳腺癌ALN性质的鉴别能力优于单独应用IVIM或DKI。

功能磁共振评估宫内发育迟缓仔鼠肾脏微观结构及灌注改变

目的探讨体素内不相干运动(intravoxel incoherent motion,IVIM)、纵向弛豫时间定量成像(T1 mapping)、横向弛豫时间定量成像(T2 mapping)等功能磁共振成像技术评估宫内发育迟缓(intrauterine growth restriction,IUGR)仔鼠的肾脏微观结构及灌注改变的价值。方法通过孕期低蛋白饮食法建立IUGR仔鼠模型。低蛋白饮食孕鼠所产仔鼠随机分为IUGR8周组、IUGR12周组,正常饮食孕鼠所产仔鼠随机分为正常8周组、正常12周组,各组n=8。比较各组仔鼠肾脏皮质、髓质的表观弥散系数(apparent diffusion coefficient,ADC)、真实扩散系数(D_(t))、伪扩散系数(D*)、灌注分数(f)、T1值、T2值,以及血肌酐、血尿素氮水平。结果IUGR 12周组肾脏髓质Dt值高于IUGR 8周组,IUGR 12周组肾脏髓质D*值低于正常12周组与IUGR 8周组(P<0.05);IUGR 8周组肾脏髓质T1值高于皮质,IUGR 12周组肾脏髓质T1值高于IUGR 8周组与正常12周组,IUGR 12周组肾脏皮质T1值高于正常12周组(P<0.05);各组内肾脏髓质T2值均高于皮质(P<0.05),各组间肾脏皮质及髓质的T2值比较差异均无统计学意义(P>0.05)。各组血肌酐及血尿素氮含量比较差异无统计学意义(P>0.05)。IUGR 8周组仔鼠肾脏可见肾小球增生肥大,未见明显纤维化改变;IUGR 12周组仔鼠肾脏可见肾小球萎缩,囊腔狭窄,间质出现炎性细胞浸润及纤维化。结论IVIM磁共振成像可用于评估及动态观察IUGR仔鼠肾脏微观结构及灌注损伤,T1 mapping磁共振成像可用于评估IUGR仔鼠肾脏损伤,T1 mapping联合T2 mapping磁共振成像可进一步分辨IUGR仔鼠的肾脏纤维化。