目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随...目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随机拆分为训练集和测试集。经图像预处理后,通过层次化建模的方法筛选特征。通过将特征按层次结构划分子类并分别考察子类建模在验证集上的表现,筛选出重要的特征,建立MR模型分别对显著性(F≥2)和进展期肝纤维化(F≥3)进行分类,并与LSM联合构建MR-LSM模型。使用受试者工作特征曲线、瀑布图、决策曲线分析评估模型的性能。结果:分类F≥2时,MR-LSM在测试集中优于MR模型(0.824 vs 0.791,P=0.003)和LSM(0.694,P=0.005)。分类F≥3时,MR-LSM AUC高于MR模型(0.855 vs 0.819,P=0.004),且优于LSM(0.731,P<0.001)。结论:MR-LSM模型在肝纤维化分级中诊断效能优于单独的MR模型和LSM,MR模型对于LSM具有附加价值。展开更多
The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MC...The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MCAO)in rats at 3T MRI,and to validate NODDI metrics with histology.A multi-shell diffusion MRI protocol was performed on 11 MCAO rats and 10 control rats at different post-operation time points of 0.5,2,6,12,24 and 72 h.NODDI orientation dispersion index(ODI)and intracellular volume fraction(V_(ic))metrics were compared between MCAO group and control group.The evolution of NODDI metrics was characterized and validated by histology.Infarction was consistent with significantly increased ODI and V_(ic)in comparison to control tissues at all time points(P<0.001).Lesion ODI increased gradually from 0.5 to 72 h,while its V_(ic)showed a more complicated and fluctuated evolution.ODI and V_(ic)were significantly different between hyperacute and acute stroke periods(P<0.001).The NODDI metrics were found to be consistent with the histological findings.In conclusion,NODDI can reflect microstructural changes of brain tissues in MCAO rats at 3T MRI and the metrics are consistent with histology.This study helps to prepare NODDI for the diagnosis and management of ischemic stroke in translational research and clinical practice.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is a major cause of cancer-related mortality worldwide.Transcatheter arterial chemoembolization(TACE)has been performed as a palliative treatment for patients with HCC.However,H...BACKGROUND Hepatocellular carcinoma(HCC)is a major cause of cancer-related mortality worldwide.Transcatheter arterial chemoembolization(TACE)has been performed as a palliative treatment for patients with HCC.However,HCC is easy to recur after TACE.Magnetic resonance imaging(MRI)has clinical potential in evaluating the TACE treatment effect for patients with liver cancer.However,traditional MRI has some limitations.AIM To explore the clinical potential of diffusion kurtosis imaging(DKI)in predicting recurrence and cellular invasion of the peritumoral liver zone of HCC after TACE.METHODSSeventy-six patients with 82 HCC nodules were recruited in this study and underwent DKI afterTACE. According to pathological examinations or the overall modified response evaluationcriteria in solid tumors (mRECIST) criterion, 48 and 34 nodules were divided into true progressionand pseudo-progression groups, respectively. The TACE-treated area, peritumoral liver zone, andfar-tumoral zone were evaluated on DKI-derived metric maps. Non-parametric U test and receiveroperating characteristic curve (ROC) analysis were used to evaluate the prediction performance ofeach DKI metric between the two groups. The independent t-test was used to compare each DKImetric between the peritumoral and far-tumoral zones of the true progression group.RESULTSDKI metrics, including mean diffusivity (MD), axial diffusivity (DA), radial diffusivity (DR), axialkurtosis (KA), and anisotropy fraction of kurtosis (Fak), showed statistically different valuesbetween the true progression and pseudo-progression groups (P < 0.05). Among these, MD, DA,and DR values were higher in pseudo-progression lesions than in true progression lesions,whereas KA and FAk values were higher in true progression lesions than in pseudo-progressionlesions. Moreover, for the true progression group, the peritumoral zone showed significantlydifferent DA, DR, KA, and FAk values from the far-tumoral zone. Furthermore, MD values of theliver parenchyma (peritumoral and far-tumoral zones) were significantly lower in the trueprogression group than in the pseudo-progression group (P < 0.05).CONCLUSIONDKI has been demonstrated with robust performance in predicting the therapeutic response ofHCC to TACE. Moreover, DKI might reveal cellular invasion of the peritumoral zone by moleculardiffusion-restricted change.展开更多
We aimed to study radiomics approach based on biparametric magnetic resonance imaging(MRI)for determining significant residual cancer after androgen deprivation therapy(ADT).Ninety-two post-ADT prostate cancer patient...We aimed to study radiomics approach based on biparametric magnetic resonance imaging(MRI)for determining significant residual cancer after androgen deprivation therapy(ADT).Ninety-two post-ADT prostate cancer patients underwent MRI before prostatectomy(62 with significant residual disease and 30 with complete response or minimum residual disease[CR/MRD]).Totally,100 significant residual,52 CR/MRD lesions,and 70 benign tissues were selected according to pathology.First,381 radiomics features were extracted from T2-weighted imaging,diffusion-weighted imaging,and apparent diffusion coefficient(ADC)maps.Optimal features were selected using a support vector machine with a recursive feature elimination algorithm(SVM-RFE).Then,ADC values of significant residual,CR/MRD lesions,and benign tissues were compared by one-way analysis of variance.Logistic regression was used to construct models with SVM features to differentiate between each pair of tissues.Third,the efficiencies of ADC value and radiomics models for differentiating the three tissues were assessed by area under receiver operating characteristic curve(AUC).The ADC value(mean±standard deviation[s.d.])of significant residual lesions([1.10±0.02]×10^(-3)mm^(2)s^(−1))was significantly lower than that of CR/MRD([1.17±0.02]×10^(-3)mm^(2)s^(−1)),which was significantly lower than that of benign tissues([1.30±0.02]×10^(-3)mm^(2)s^(−1);both P<0.05).The SVM feature models were comparable to ADC value in distinguishing CR/MRD from benign tissue(AUC:0.766 vs 0.792)and distinguishing residual from benign tissue(AUC:0.825 vs 0.835)(both P>0.05),but superior to ADC value in differentiating significant residual from CR/MRD(AUC:0.748 vs 0.558;P=0.041).Radiomics approach with biparametric MRI could promote the detection of significant residual prostate cancer after ADT.展开更多
Objective.Atherosclerosis is a leading cause of mortality and morbidity.Optical endoscopy,ultrasound,and X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease and t...Objective.Atherosclerosis is a leading cause of mortality and morbidity.Optical endoscopy,ultrasound,and X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease and therapeutic response.Magnetic resonance imaging(MRI)endoscopy is a newer idea employing tiny catheter-mounted detectors connected to the MRI scanner.It can see through vessel walls and provide soft-tissue sensitivity,but its slow imaging speed limits practical applications.Our goal is highresolution MRI endoscopy with real-time imaging speeds comparable to existing modalities.Methods.Intravascular(3 mm)transmit-receive MRI endoscopes were fabricated for highly undersampled radial-projection MRI in a clinical 3-tesla MRI scanner.Iterative nonlinear reconstruction was accelerated using graphics processor units connected via a single ethernet cable to achieve true real-time endoscopy visualization at the scanner.MRI endoscopy was performed at 6-10 frames/sec and 200-300μm resolution in human arterial specimens and porcine vessels ex vivo and in vivo and compared with fully sampled 0.3 frames/sec and three-dimensional reference scans using mutual information(MI)and structural similarity(3-SSIM)indices.Results.High-speed MRI endoscopy at 6-10 frames/sec was consistent with fully sampled MRI endoscopy and histology,with feasibility demonstrated in vivo in a large animal model.A 20-30-fold speed-up vs.0.3 frames/sec reference scans came at a cost of~7%in MI and~45%in 3-SSIM,with reduced motion sensitivity.Conclusion.High-resolution MRI endoscopy can now be performed at frame rates comparable to those of X-ray and optical endoscopy and could provide an alternative to existing modalities,with MRI’s advantages of soft-tissue sensitivity and lack of ionizing radiation.展开更多
Background: The aim of this study was to evaluate the feasibility of a dualbolus protocol, where a first bolus of an intravascular tracer is used to measure perfusion, followed by a second bolus of a freely filtered g...Background: The aim of this study was to evaluate the feasibility of a dualbolus protocol, where a first bolus of an intravascular tracer is used to measure perfusion, followed by a second bolus of a freely filtered gadolinium-containing agent to measure filtration capacity. Methods: The study was conducted in mice subjected to complete unilateral ureteral obstruction (UUO), and sham operated mice were used as controls. Dynamic contrast- en-hanced MRI was performed 2 days after surgery. Results and discussions: Mean signal-time curves of the renal cortex, renal medulla and abdominal aorta were used to calculate the relative renal blood flow (rRBF), relative renal blood volume (rRBV), mean transit time (MTT) and the glomerular transfer rate Ktrans. We demonstrated that kidneys suffering from two days of UUO showed a decrease in cortical as well as medullary rRBF compared to kidneys from sham-operated mice. Further, we found no changes in rRBV and MTT among groups, neither in the cortex nor in the medulla. The renal functional parameter Ktrans showed a tendency (but statistically insignificant) to be reduced in the ob-structed kidney compared to the sham-operated mice. Conclusions: We showed our first experiences with the consecutive use of intra- and extra-vascularly distributed agents in a renal-diseased mouse model, allowing analysis of both functional haemo- dyamics and filtration capacity in kidneys.展开更多
目的:探讨早期宫颈癌患者的MRI影像表型与各种临床及组织病理学特征之间的相关性。方法:回顾性收集2019年7月—2023年12月164例早期宫颈癌患者的磁共振影像组学特征和临床及组织病理学特征。将所有患者的肿瘤和盆腔淋巴结通过基于影像...目的:探讨早期宫颈癌患者的MRI影像表型与各种临床及组织病理学特征之间的相关性。方法:回顾性收集2019年7月—2023年12月164例早期宫颈癌患者的磁共振影像组学特征和临床及组织病理学特征。将所有患者的肿瘤和盆腔淋巴结通过基于影像组学特征的一致性聚类分为两组,比较两组患者的临床及组织病理学特征的差异。结果:基于肿瘤的聚类分析显示,两组在平均年龄、组织学类型、肿瘤分化程度、淋巴血管间隙侵犯以及宫旁浸润上差异均没有统计学意义。与组1相比,组2患者的术后国际妇产科联盟(Federation International of Gynecology and Obstetrics,FIGO)分期更晚[ⅡA期及以上:22/72(30.6%)vs.56/92(60.9%),P=0.001]、淋巴结转移的概率更大[9/72(12.5%)vs.30/92(32.6%),P=0.002]、肿瘤更大[短径:(16.67±6.32)mm vs.(28.38±9.73)mm,长径:(21.02±7.39)mm vs.(34.34±9.72)mm,高度:(18.93±8.01)mm vs.(29.92±10.61)mm,P均<0.001],且具有更深的间质浸润深度[>2/3:26/72(36.1%)vs.62/92(67.4%),P<0.001]。基于淋巴结的聚类分析显示两组在短径、长径、短长比、信号、边缘和淋巴结转移差异没有统计学意义。结论:基于肿瘤的多参数磁共振影像组学一致性聚类分析有助于识别早期宫颈癌患者影像组学特征与临床及组织病理学特征的关联,从而为术前危险分层提供了依据。展开更多
文摘目的:构建并验证基于磁共振增强平衡期(T1-delay MR)的机器学习模型(MR模型)无创评估肝脏纤维化分级,并与超声瞬时弹性成像肝硬度值(LSM)进行联合/对比,探讨MR模型对于LSM的附加价值。方法:回顾性单中心研究纳入了659例肝纤维化患者,随机拆分为训练集和测试集。经图像预处理后,通过层次化建模的方法筛选特征。通过将特征按层次结构划分子类并分别考察子类建模在验证集上的表现,筛选出重要的特征,建立MR模型分别对显著性(F≥2)和进展期肝纤维化(F≥3)进行分类,并与LSM联合构建MR-LSM模型。使用受试者工作特征曲线、瀑布图、决策曲线分析评估模型的性能。结果:分类F≥2时,MR-LSM在测试集中优于MR模型(0.824 vs 0.791,P=0.003)和LSM(0.694,P=0.005)。分类F≥3时,MR-LSM AUC高于MR模型(0.855 vs 0.819,P=0.004),且优于LSM(0.731,P<0.001)。结论:MR-LSM模型在肝纤维化分级中诊断效能优于单独的MR模型和LSM,MR模型对于LSM具有附加价值。
基金National Natural Science Foundation of China(No.81570462,No.81730049,and No.81801666).
文摘The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MCAO)in rats at 3T MRI,and to validate NODDI metrics with histology.A multi-shell diffusion MRI protocol was performed on 11 MCAO rats and 10 control rats at different post-operation time points of 0.5,2,6,12,24 and 72 h.NODDI orientation dispersion index(ODI)and intracellular volume fraction(V_(ic))metrics were compared between MCAO group and control group.The evolution of NODDI metrics was characterized and validated by histology.Infarction was consistent with significantly increased ODI and V_(ic)in comparison to control tissues at all time points(P<0.001).Lesion ODI increased gradually from 0.5 to 72 h,while its V_(ic)showed a more complicated and fluctuated evolution.ODI and V_(ic)were significantly different between hyperacute and acute stroke periods(P<0.001).The NODDI metrics were found to be consistent with the histological findings.In conclusion,NODDI can reflect microstructural changes of brain tissues in MCAO rats at 3T MRI and the metrics are consistent with histology.This study helps to prepare NODDI for the diagnosis and management of ischemic stroke in translational research and clinical practice.
基金the Greater Bay Area Institute of Precision Medicine,No.KCH2310094Shanghai Sailing Program,No.22YF1405000+1 种基金Research Startup Fund of Huashan Hospital Fudan University,No.2021QD035and Clinical Research Plan of SHDC,No.SHDC2020CR3020A.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is a major cause of cancer-related mortality worldwide.Transcatheter arterial chemoembolization(TACE)has been performed as a palliative treatment for patients with HCC.However,HCC is easy to recur after TACE.Magnetic resonance imaging(MRI)has clinical potential in evaluating the TACE treatment effect for patients with liver cancer.However,traditional MRI has some limitations.AIM To explore the clinical potential of diffusion kurtosis imaging(DKI)in predicting recurrence and cellular invasion of the peritumoral liver zone of HCC after TACE.METHODSSeventy-six patients with 82 HCC nodules were recruited in this study and underwent DKI afterTACE. According to pathological examinations or the overall modified response evaluationcriteria in solid tumors (mRECIST) criterion, 48 and 34 nodules were divided into true progressionand pseudo-progression groups, respectively. The TACE-treated area, peritumoral liver zone, andfar-tumoral zone were evaluated on DKI-derived metric maps. Non-parametric U test and receiveroperating characteristic curve (ROC) analysis were used to evaluate the prediction performance ofeach DKI metric between the two groups. The independent t-test was used to compare each DKImetric between the peritumoral and far-tumoral zones of the true progression group.RESULTSDKI metrics, including mean diffusivity (MD), axial diffusivity (DA), radial diffusivity (DR), axialkurtosis (KA), and anisotropy fraction of kurtosis (Fak), showed statistically different valuesbetween the true progression and pseudo-progression groups (P < 0.05). Among these, MD, DA,and DR values were higher in pseudo-progression lesions than in true progression lesions,whereas KA and FAk values were higher in true progression lesions than in pseudo-progressionlesions. Moreover, for the true progression group, the peritumoral zone showed significantlydifferent DA, DR, KA, and FAk values from the far-tumoral zone. Furthermore, MD values of theliver parenchyma (peritumoral and far-tumoral zones) were significantly lower in the trueprogression group than in the pseudo-progression group (P < 0.05).CONCLUSIONDKI has been demonstrated with robust performance in predicting the therapeutic response ofHCC to TACE. Moreover, DKI might reveal cellular invasion of the peritumoral zone by moleculardiffusion-restricted change.
基金supported by the Clinical Science and Research Fund of Shanghai Municipal Health Commission,Shanghai,China (No.2020040270).
文摘We aimed to study radiomics approach based on biparametric magnetic resonance imaging(MRI)for determining significant residual cancer after androgen deprivation therapy(ADT).Ninety-two post-ADT prostate cancer patients underwent MRI before prostatectomy(62 with significant residual disease and 30 with complete response or minimum residual disease[CR/MRD]).Totally,100 significant residual,52 CR/MRD lesions,and 70 benign tissues were selected according to pathology.First,381 radiomics features were extracted from T2-weighted imaging,diffusion-weighted imaging,and apparent diffusion coefficient(ADC)maps.Optimal features were selected using a support vector machine with a recursive feature elimination algorithm(SVM-RFE).Then,ADC values of significant residual,CR/MRD lesions,and benign tissues were compared by one-way analysis of variance.Logistic regression was used to construct models with SVM features to differentiate between each pair of tissues.Third,the efficiencies of ADC value and radiomics models for differentiating the three tissues were assessed by area under receiver operating characteristic curve(AUC).The ADC value(mean±standard deviation[s.d.])of significant residual lesions([1.10±0.02]×10^(-3)mm^(2)s^(−1))was significantly lower than that of CR/MRD([1.17±0.02]×10^(-3)mm^(2)s^(−1)),which was significantly lower than that of benign tissues([1.30±0.02]×10^(-3)mm^(2)s^(−1);both P<0.05).The SVM feature models were comparable to ADC value in distinguishing CR/MRD from benign tissue(AUC:0.766 vs 0.792)and distinguishing residual from benign tissue(AUC:0.825 vs 0.835)(both P>0.05),but superior to ADC value in differentiating significant residual from CR/MRD(AUC:0.748 vs 0.558;P=0.041).Radiomics approach with biparametric MRI could promote the detection of significant residual prostate cancer after ADT.
基金supported by grants R01 EB007829 from the National Institutes of Health,Siemens Medical SystemsRussell H Morgan Professorship in Radiology。
文摘Objective.Atherosclerosis is a leading cause of mortality and morbidity.Optical endoscopy,ultrasound,and X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease and therapeutic response.Magnetic resonance imaging(MRI)endoscopy is a newer idea employing tiny catheter-mounted detectors connected to the MRI scanner.It can see through vessel walls and provide soft-tissue sensitivity,but its slow imaging speed limits practical applications.Our goal is highresolution MRI endoscopy with real-time imaging speeds comparable to existing modalities.Methods.Intravascular(3 mm)transmit-receive MRI endoscopes were fabricated for highly undersampled radial-projection MRI in a clinical 3-tesla MRI scanner.Iterative nonlinear reconstruction was accelerated using graphics processor units connected via a single ethernet cable to achieve true real-time endoscopy visualization at the scanner.MRI endoscopy was performed at 6-10 frames/sec and 200-300μm resolution in human arterial specimens and porcine vessels ex vivo and in vivo and compared with fully sampled 0.3 frames/sec and three-dimensional reference scans using mutual information(MI)and structural similarity(3-SSIM)indices.Results.High-speed MRI endoscopy at 6-10 frames/sec was consistent with fully sampled MRI endoscopy and histology,with feasibility demonstrated in vivo in a large animal model.A 20-30-fold speed-up vs.0.3 frames/sec reference scans came at a cost of~7%in MI and~45%in 3-SSIM,with reduced motion sensitivity.Conclusion.High-resolution MRI endoscopy can now be performed at frame rates comparable to those of X-ray and optical endoscopy and could provide an alternative to existing modalities,with MRI’s advantages of soft-tissue sensitivity and lack of ionizing radiation.
文摘Background: The aim of this study was to evaluate the feasibility of a dualbolus protocol, where a first bolus of an intravascular tracer is used to measure perfusion, followed by a second bolus of a freely filtered gadolinium-containing agent to measure filtration capacity. Methods: The study was conducted in mice subjected to complete unilateral ureteral obstruction (UUO), and sham operated mice were used as controls. Dynamic contrast- en-hanced MRI was performed 2 days after surgery. Results and discussions: Mean signal-time curves of the renal cortex, renal medulla and abdominal aorta were used to calculate the relative renal blood flow (rRBF), relative renal blood volume (rRBV), mean transit time (MTT) and the glomerular transfer rate Ktrans. We demonstrated that kidneys suffering from two days of UUO showed a decrease in cortical as well as medullary rRBF compared to kidneys from sham-operated mice. Further, we found no changes in rRBV and MTT among groups, neither in the cortex nor in the medulla. The renal functional parameter Ktrans showed a tendency (but statistically insignificant) to be reduced in the ob-structed kidney compared to the sham-operated mice. Conclusions: We showed our first experiences with the consecutive use of intra- and extra-vascularly distributed agents in a renal-diseased mouse model, allowing analysis of both functional haemo- dyamics and filtration capacity in kidneys.
文摘目的:探讨早期宫颈癌患者的MRI影像表型与各种临床及组织病理学特征之间的相关性。方法:回顾性收集2019年7月—2023年12月164例早期宫颈癌患者的磁共振影像组学特征和临床及组织病理学特征。将所有患者的肿瘤和盆腔淋巴结通过基于影像组学特征的一致性聚类分为两组,比较两组患者的临床及组织病理学特征的差异。结果:基于肿瘤的聚类分析显示,两组在平均年龄、组织学类型、肿瘤分化程度、淋巴血管间隙侵犯以及宫旁浸润上差异均没有统计学意义。与组1相比,组2患者的术后国际妇产科联盟(Federation International of Gynecology and Obstetrics,FIGO)分期更晚[ⅡA期及以上:22/72(30.6%)vs.56/92(60.9%),P=0.001]、淋巴结转移的概率更大[9/72(12.5%)vs.30/92(32.6%),P=0.002]、肿瘤更大[短径:(16.67±6.32)mm vs.(28.38±9.73)mm,长径:(21.02±7.39)mm vs.(34.34±9.72)mm,高度:(18.93±8.01)mm vs.(29.92±10.61)mm,P均<0.001],且具有更深的间质浸润深度[>2/3:26/72(36.1%)vs.62/92(67.4%),P<0.001]。基于淋巴结的聚类分析显示两组在短径、长径、短长比、信号、边缘和淋巴结转移差异没有统计学意义。结论:基于肿瘤的多参数磁共振影像组学一致性聚类分析有助于识别早期宫颈癌患者影像组学特征与临床及组织病理学特征的关联,从而为术前危险分层提供了依据。
