Reproducibility study of intravoxel incoherent motion and apparent diffusion coefficient parameters in normal pancreas

BACKGROUND The consistency of pancreatic apparent diffusion coefficient(ADC)values and intravoxel incoherent motion(IVIM)parameter values across different magnetic resonance imaging(MRI)devices significantly impacts the patient’s diagnosis and treatment.AIM To explore consistency in image quality,ADC values,and IVIM parameter values among different MRI devices in pancreatic examinations.METHODS This retrospective study was approved by the local ethics committee,and informed consent was obtained from all participants.In total,22 healthy volunteers(10 males and 12 females)aged 24-61 years(mean,28.9±2.3 years)underwent pancreatic diffusion-weighted imaging using 3.0T MRI equipment from three vendors.Two independent observers subjectively scored image quality and measured the pancreas’s overall ADC values and signal-to-noise ratios(SNRs).Subsequently,regions of interest(ROIs)were delineated for the IVIM parameters(true diffusion coefficient,pseudo-diffusion coefficient,and perfusion fraction)using post-processing software.These ROIs were on the head,body,and tail of the pancrease.The subjective image ratings were assessed using the kappa consistency test.Intraclass correlation coefficients(ICCs)and mixed linear models were used to evaluate each device’s quantitative parameter values.Finally,a pairwise analysis of IVIM parameter values across each device was performed using Bland-Altman plots.RESULTS The Kappa value for the subjective ratings of the different observers was 0.776(P<0.05).The ICC values for interobserver and intra-observer agreements for the quantitative parameters were 0.803[95% confidence interval(CI):0.684-0.880]and 0.883(95%CI:0.760-0.945),respectively(P<0.05).The ICCs for the SNR between different devices was comparable(P>0.05),and the ICCs for the ADC values from different devices were 0.870,0.707,and 0.808,respectively(P<0.05).Notably,only a few statistically significant inter-device agreements were observed for different IVIM parameters,and among those,the ICC values were generally low.The mixed linear model results indicated differences(P<0.05)in the f-value for the pancreas head,D-value for the pancreas body,and D-value for the pancreas tail obtained using different MRI machines.The Bland-Altman plots showed significant variability at some data points.CONCLUSION ADC values are consistent among different devices,but the IVIM parameters’repeatability is moderate.Therefore,the variability in the IVIM parameter values may be associated with using different MRI machines.Thus,caution should be exercised when using IVIM parameter values to assess the pancreas.

Intravoxel incoherent motion diffusion-weighted magnetic resonance imaging for predicting histological grade of hepatocellular carcinoma:Comparison with conventional diffusion-weighted imaging

AIM To compare intravoxel incoherent motion(IVIM)-derived parameters with conventional diffusion-weighted imaging(DWI) parameters in predicting the histological grade of hepatocellular carcinoma(h CC) and to evaluate the correlation between the parameters and the histological grades.METHODS A retrospective study was performed. Sixty-two patients with surgically confirmed h CCs underwent diffusion-weighted magnetic resonance imaging with twelve b values(10-1200 s/mm^2). The apparent diffusion coefficient(ADC), pure diffusion coefficient(D), pseudo-diffusion coefficient(D*), and perfusion fraction(f) were calculated by two radiologists. The IVIM and conventional DWI parameters were compared among the different grades by using analysis of variance(ANOVA) and the Kruskal-Wallis test. Receiver operating characteristic(ROC) analysis was performed to evaluate the diagnostic efficiency of distinguishing between low-grade(grade 1, G1) and high-grade(grades 2 and 3, G2 and G3) hC C. The correlation between the parameters and the histological grades was assessed by using the Spearman correlation test. Bland-Altman analysis was used to evaluate the reproducibility of the two radiologists' measurements.RESULTS The differences in the ADC and D values among the groups with G1, G2, and G3 histological grades of HCCs were statistically significant(P < 0.001). The D* and f values had no significant differences among the different histological grades of h CC(P > 0.05). The ROC analyses demonstrated that the D and ADC values had better diagnostic performance in differentiating the low-grade h CC from the high-grade h CC, with areas under the curve(AUCs) of 0.909 and 0.843, respectively, measured by radiologist 1 and of 0.911 and 0.852, respectively, measured by radiologist 2. The following significant correlations were obtained between the ADC, D, and D~* values and the histological grades: r =-0.619(P < 0.001), r =-0.628(P < 0.001), and r =-0.299(P = 0.018), respectively, as measured by radiologist 1; r =-0.622(P < 0.001), r =-0.633(P < 0.001), and r =-0.303(P = 0.017), respectively, as measured by radiologist 2. The intra-class correlation coefficient(ICC) values between the two observers were 0.996 for ADC, 0.997 for D, 0.996 for D*, and 0.992 for f values, which indicated excellent interobserver agreement in the measurements between the two observers.CONCLUSION The IVIM-derived D and ADC values show better diagnostic performance in differentiating high-grade hC C from low-grade hC C, and there is a moderate to good correlation between the ADC and D values and the histological grades.

Liver intravoxel incoherent motion diffusion-weighted imaging for the assessment of hepatic steatosis and fibrosis in children

AIM To evaluate the correlation between intravoxel incoherent motion(IVIM) diffusion-weighted imaging(DWI) parameters and the degree of hepatic steatosis and fibrosis in children.METHODS This retrospective study was approved by the institutional review board. The children(≤ 18 years) who underwent liver IVIM DWI with 8 b-values under the suspicion of hepatic steatosis or fibrosis from February 2013 to November 2016 were included. Subjects were divided into normal, fatty liver(FAT), and fibrotic liver(FIB) groups. The slow diffusion coefficient(D), fast diffusion coefficient(D*), perfusion fraction(f), and apparent diffusion coefficient(ADC) were measured. MR proton density fat fraction(PDFF), MR elastography(MRE), and IVIM values were compared.RESULTS A total of 123 children(median age of 12 years old, range: 6-18 years) were included, with 8 in the normal group, 93 in the FAT group, and 22 in the FIB group. The D* values were lower in the FIB group compared with those of the normal(P = 0.015) and FAT(P = 0.003) groups. The f values were lower in the FIB group compared with the FAT group(P = 0.001). In multivariate analyses, PDFF value was positively correlated with f value(β = 3.194, P < 0.001), and MRE value was negatively correlated with D* value(β =-7.031, P = 0.032). The D and ADC values were not influenced by PDFF or MRE value.CONCLUSION In liver IVIM DWI with multiple b-values in children, there was a positive correlation between hepatic fat and blood volume, and a negative correlation between hepatic stiffness and endovascular blood flow velocity, while diffusion-related parameters were not affected.

Intravoxel incoherent motion diffusion-weighted imaging for monitoring chemotherapeutic efficacy in gastric cancer

AIM: To assess intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for monitoring early efficacy of chemotherapy in a human gastric cancer mouse model.METHODS: IVIM-DWI was performed with 12 b-values (0-800 s/mm2) in 25 human gastric cancer-bearing nude mice at baseline (day 0), and then they were randomly divided into control and 1-, 3-, 5- and 7-d treatment groups (n = 5 per group). The control group underwent longitudinal MRI scans at days 1, 3, 5 and 7, and the treatment groups underwent subsequent MRI scans after a specified 5-fluorouracil/calcium folinate treatment. Together with tumor volumes (TV), the apparent diffusion coefficient (ADC) and IVIM parameters [true water molecular diffusion coefficient (D), perfusion fraction (f) and pseudo-related diffusion coefficient (D*)] were measured. The differences in those parameters from baseline to each measurement (ΔTV%, ΔADC%, ΔD%, Δf% and ΔD*%) were calculated. After image acquisition, tumor necrosis, microvessel density (MVD) and cellular apoptosis were evaluated by hematoxylin-eosin (HE), CD31 and terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining respectively, to confirm the imaging findings. Mann-Whitney test and Spearman’s correlation coefficient analysis were performed.RESULTS: The observed relative volume increase (ΔTV%) in the treatment group were significantly smaller than those in the control group at day 5 (ΔTVtreatment% = 19.63% ± 3.01% and ΔTVcontrol% = 83.60% ± 14.87%, P = 0.008) and day 7 (ΔTVtreatment% = 29.07% ± 10.01% and ΔTVcontrol% = 177.06% ± 63.00%, P = 0.008). The difference in ΔTV% between the treatment and the control groups was not significant at days 1 and 3 after a short duration of treatment. Increases in ADC in the treatment group (ΔADC%treatment, median, 30.10% ± 18.32%, 36.11% ± 21.82%, 45.22% ± 24.36%) were significantly higher compared with the control group (ΔADC%control, median, 4.98% ± 3.39%, 6.26% ± 3.08%, 9.24% ± 6.33%) at days 3, 5 and 7 (P = 0.008, P = 0.016, P = 0.008, respectively). Increases in D in the treatment group (ΔD%treatment, median 17.12% ± 8.20%, 24.16% ± 16.87%, 38.54% ± 19.36%) were higher than those in the control group (ΔD%control, median -0.13% ± 4.23%, 5.89% ± 4.56%, 5.54% ± 4.44%) at days 1, 3, and 5 (P = 0.032, P = 0.008, P = 0.016, respectively). Relative changes in f were significantly lower in the treatment group compared with the control group at days 1, 3, 5 and 7 follow-up (median, -34.13% ± 16.61% vs 1.68% ± 3.40%, P = 0.016; -50.64% ± 6.82% vs 3.01% ± 6.50%, P = 0.008; -49.93% ± 6.05% vs 0.97% ± 4.38%, P = 0.008, and -46.22% ± 7.75% vs 8.14% ± 6.75%, P = 0.008, respectively). D* in the treatment group decreased significantly compared to those in the control group at all time points (median, -32.10% ± 12.22% vs 1.85% ± 5.54%, P = 0.008; -44.14% ± 14.83% vs 2.29% ± 10.38%, P = 0.008; -59.06% ± 19.10% vs 3.86% ± 5.10%, P = 0.008 and -47.20% ± 20.48% vs 7.13% ± 9.88%, P = 0.016, respectively). Furthermore, histopathologic findings showed positive correlations with ADC and D and tumor necrosis (rs = 0.720, P < 0.001; rs = 0.522, P = 0.007, respectively). The cellular apoptosis of the tumor also showed positive correlations with ADC and D (rs = 0.626, P = 0.001; rs = 0.542, P = 0.005, respectively). Perfusion-related parameters (f and D*) were positively correlated to MVD (rs = 0.618, P = 0.001; rs = 0.538, P = 0.006, respectively), and negatively correlated to cellular apoptosis of the tumor (rs = -0.550, P = 0.004; rs = -0.692, P < 0.001, respectively).CONCLUSION: IVIM-DWI is potentially useful for predicting the early efficacy of chemotherapy in a human gastric cancer mouse model.

Intravoxel Incoherent Motion Diffusion Weighted Imaging for the Therapeutic Response of Transarterial Chemoembolization for Hepatocellular Carcinoma

Background: Intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) can not only observe the diffusion of tissue water molecules but also reflect the blood perfusion information of tissue microcirculation. IVIM-DWI has been applied in many clinical areas. However, few studies have addressed the use of IVIM-DWI for the evaluation of transarterial chemoembolization (TACE) response in hepatocellular carcinoma (HCC) patients. Objectives: The purpose of the present study was to explore the role of IVIM-DWI for the therapeutic response of TACE for HCC. Materials and Methods: Twenty patients underwent IVIM-DWI scan on a 3.0T magnetic resonance imaging instrument 1 - 3 days before and 30 to 40 days after TACE. The values of IVIM-DWI parameters, including standard apparent diffusion coefficient (ADC), pure diffusion coefficient (Dslow), pseudo-diffusion coefficient (Dfast) and perfusion fraction (f) were measured. The values of IVIM-DWI parameters before and after TACE were compared using paired t tests. The values between responsive and non-responsive groups were compared using independent-samples t test. P 0.05 indicated statistical significance. Results: After TACE, the ADC and Dslow values in the tumors increased significantly, and the values of Dfast decreased significantly, while the values of f value did not change obviously. The ADC values in responsive group were remarkably higher than those in non-responsive group, the Dfast values in responsive group were significantly lower than those in non-responsive group, but the values of Dslow and f between the two groups were not different significantly. Conclusions: IVIM-DWI parameters can be used as potential markers for the therapeutic response of TACE for HCC.

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.

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.

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.

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.

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.

Advances in the imaging of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms comprise a heterogeneous group of tumors that differ in their pathogenesis,hormonal syndromes produced,biological behavior and consequently,in their requirement for and/or response to specific chemotherapeutic agents and molecular targeted therapies.Various imaging techniques are available for functional and morphological evaluation of these neoplasms and the selection of investigations performed in each patient should be customized to the clinical question.Also,with the increased availability of cross sectional imaging,these neoplasms are increasingly being detected incidentally in routine radiology practice.This article is a review of the various imaging modalities currently used in the evaluation of neuroendocrine neoplasms,along with a discussion of the role of advanced imaging techniques and a glimpse into the newer imaging horizons,mostly in the research stage.

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。

应用IVIM-DWI研究正常胰腺及急性胰腺炎不同解剖部位

目的应用体素内不相干运动扩散加权成像研究正常胰腺及急性胰腺炎的不同,探讨正常胰腺及急性胰腺炎的胰腺不同解剖部位参数差异及意义。方法29名健康志愿者及33例AP患者行上腹部MRI及IVIM-DWI扫描,测量胰腺头部、颈体部、尾部ADC、f、D、D*值。采用单因素方差、LSD检验和独立样本t检验对比分析正常胰腺及AP胰腺参数差异性。结果正常胰腺不同解剖部位ADC值及f值差异显著,病变为弥漫AP者不同解剖部位各参数差异无统计学意义。AP患者ADC、f、D值均低于正常胰腺,D值高于正常胰腺,差异均有统计学意义(P<0.05)。病变为局限AP患者ADC及f值由高到低排序为NP组>非病变区>病变区,差异有统计学意义(P<0.05)。结论胰腺不同解剖部位ADC、f、D、D*值有作为甄别急性胰腺炎指标的可能,其中f值是间接评估胰腺不同解剖部位微循环灌注情况的主要参数。

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.

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。