为提升磁性纳米粒子三维成像和重构速度,降低三维重构对采样投影数据完备性要求,针对含噪声投影数据三维重构优化问题,本文提出了一种具有噪声鲁棒性的三维磁性纳米粒子成像快速重构方法(noise-robust 3D sparse sampling magnetic part...为提升磁性纳米粒子三维成像和重构速度,降低三维重构对采样投影数据完备性要求,针对含噪声投影数据三维重构优化问题,本文提出了一种具有噪声鲁棒性的三维磁性纳米粒子成像快速重构方法(noise-robust 3D sparse sampling magnetic particle imaging,3D NRSS-MPI).该算法通过求解一个由MPI投影成像正向模型l2范数和稀疏正则约束建立的凸优化问题实现3D MPI图像重构.模型不受MPI扫描轨迹限制,为不断发展的MPI新技术提供了普适性的基础模型;建立的三维全变分稀疏算子(3D total variation sparse operator, 3D TV Sparse Operator)利用MPI先验信息提升含噪MPI投影数据三维重构的鲁棒性,且可以进行无矩阵运算,大幅提升了运算效率.通过点源和冠状血管模型成像实验表明,在1/4欠采样下,本文3D NRSS-MPI方法可以有效消除重构图像星状伪影,获取较高的图像信噪比,同时冠状动脉重建结构相似性超过0.701,可以准确地对欠采样、有噪声的MPI数据进行快速而稳健的重建,有效缩短了4倍成像和重构时间.展开更多
Objective To observe the value of long TR three-dimensional inversion recovery sequence with real reconstruction(3D real IR)for quantifying inner ear endolymphatic hydrops(EH).Methods Totally 46 Ménière'...Objective To observe the value of long TR three-dimensional inversion recovery sequence with real reconstruction(3D real IR)for quantifying inner ear endolymphatic hydrops(EH).Methods Totally 46 Ménière's disease(MD)patients and 21 healthy volunteers were prospectively enrolled.MR scanning for inner ear based on 3D real IR and 3D fluid attenuated inversion recovery(3D FLAIR)sequence 4—6 h after administration of contrast agents were performed.The imaging qualities were scored and compared between groups.The endolymphatic space area and the membranous labyrinth area of cochlea and vestibule,as well as endolymph/membranous labyrinth area percentage were calculated,the present or not of EH and the grade of EH were evaluated.EH inner ears of MD patients were enrolled in EH group,while inner ears of healthy volunteers were taken as controls(control group).The endolymphatic space area,membranous labyrinth area and endolymph/membranous labyrinth area percentage of cochlea and vestibule were compared between groups.The receiver operating characteristic(ROC)curve was drawn to calculate the diagnostic efficacy of the above indexes.Results Cochlear and/or vestibular EH were detected in 56 ears,including cochlear EH in 52 ears and vestibular EH in 45 ears among 46 MD patients(EH group),but not in 42 ears in control group.The subjective quality scores of 3D real IR images were higher than those of 3D-FLAIR(both P<0.05).Quantitative analysis based on 3D real IR images revealed that,compared with control group,significantly larger endolymph areas and endolymph/membranous labyrinth area percentages in both cochlea and vestibule were found in EH group(all P<0.001).The area under the curve(AUC)of cochlear or vestibular endolymph/membranous labyrinth area percentage for identifying inner ear EH was 0.999 and 0.985,respectively.Taken 13.64%and 24.13%as the critical value of cochlear or vestibular endolymph,the specificity was 100%and 92.86%,respectively,and the sensitivity was 96.43%and 96.43%,respectively.Conclusion MR long TR 3D real IR was helpful to quantifying inner ear EH.展开更多
Objective To observe the value of isotropic volumetric MRI for displaying perineural spread(PNS)of cranial nerve(CN)in nasopharyngeal carcinoma.Methods Eighty-seven patients with pathologically proven nasopharyngeal c...Objective To observe the value of isotropic volumetric MRI for displaying perineural spread(PNS)of cranial nerve(CN)in nasopharyngeal carcinoma.Methods Eighty-seven patients with pathologically proven nasopharyngeal carcinoma were prospectively enrolled.MR scanning,including three-dimensional liver acquisition with volume acceleration-flexible(3D LAVA_Flex)image,T2WI with fat suppression(T2WI-FS),T1WI,contrast enhancement(CE)T1WI-FS of nasopharynx and neck region were performed.The displaying rates of CN PNS were evaluated and compared between 3D LAVA_Flex and T2WI-FS,T1WI,CE-T1WI-FS at patient level,CN group level and neural level,respectively.Results The displaying rate of CN PNS in all 87 nasopharyngeal carcinoma patients by 3D LAVA_Flex sequence was 49.43%(43/87),higher than that of conventional MRI(30/87,34.48%,P=0.001).Among 59 patients with advanced nasopharyngeal carcinoma diagnosed with conventional sequences,the displaying rate of CN PNS was 71.19%(42/59)by 3D LAVA-Flex sequence,higher than that of conventional MRI(30/59,50.85%,P=0.001).At both patient level and posterior CN level,significant differences of the displaying rate of CN PNS were found between 3D LAVA-Flex sequence and T2WI-FS,T1WI,CE-T1WI-FS,while at CN level,the displaying rates of mandibular nerve PNS,CNⅨ—ⅪPNS in jugular foramen(P<0.05)and CNⅨ—ⅫPNS in carotid space of 3D LAVA_Flex sequence were all significantly higher than that of T2WI-FS,T1WI and CE-T1WI-FS(all P<0.05),of PNS of CNⅢ—Ⅴin cavernous sinus were higher than that of T2WI-FS(P<0.05),while of PNS of hypoglossal nerve were significantly higher than that of T2WI-FS and T1WI(both P<0.05).Conclusion 3D LAVA_Flex sequence could be used to effectively display CN PNS of nasopharyngeal carcinoma.展开更多
Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 n...Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.展开更多
文摘为提升磁性纳米粒子三维成像和重构速度,降低三维重构对采样投影数据完备性要求,针对含噪声投影数据三维重构优化问题,本文提出了一种具有噪声鲁棒性的三维磁性纳米粒子成像快速重构方法(noise-robust 3D sparse sampling magnetic particle imaging,3D NRSS-MPI).该算法通过求解一个由MPI投影成像正向模型l2范数和稀疏正则约束建立的凸优化问题实现3D MPI图像重构.模型不受MPI扫描轨迹限制,为不断发展的MPI新技术提供了普适性的基础模型;建立的三维全变分稀疏算子(3D total variation sparse operator, 3D TV Sparse Operator)利用MPI先验信息提升含噪MPI投影数据三维重构的鲁棒性,且可以进行无矩阵运算,大幅提升了运算效率.通过点源和冠状血管模型成像实验表明,在1/4欠采样下,本文3D NRSS-MPI方法可以有效消除重构图像星状伪影,获取较高的图像信噪比,同时冠状动脉重建结构相似性超过0.701,可以准确地对欠采样、有噪声的MPI数据进行快速而稳健的重建,有效缩短了4倍成像和重构时间.
文摘Objective To observe the value of long TR three-dimensional inversion recovery sequence with real reconstruction(3D real IR)for quantifying inner ear endolymphatic hydrops(EH).Methods Totally 46 Ménière's disease(MD)patients and 21 healthy volunteers were prospectively enrolled.MR scanning for inner ear based on 3D real IR and 3D fluid attenuated inversion recovery(3D FLAIR)sequence 4—6 h after administration of contrast agents were performed.The imaging qualities were scored and compared between groups.The endolymphatic space area and the membranous labyrinth area of cochlea and vestibule,as well as endolymph/membranous labyrinth area percentage were calculated,the present or not of EH and the grade of EH were evaluated.EH inner ears of MD patients were enrolled in EH group,while inner ears of healthy volunteers were taken as controls(control group).The endolymphatic space area,membranous labyrinth area and endolymph/membranous labyrinth area percentage of cochlea and vestibule were compared between groups.The receiver operating characteristic(ROC)curve was drawn to calculate the diagnostic efficacy of the above indexes.Results Cochlear and/or vestibular EH were detected in 56 ears,including cochlear EH in 52 ears and vestibular EH in 45 ears among 46 MD patients(EH group),but not in 42 ears in control group.The subjective quality scores of 3D real IR images were higher than those of 3D-FLAIR(both P<0.05).Quantitative analysis based on 3D real IR images revealed that,compared with control group,significantly larger endolymph areas and endolymph/membranous labyrinth area percentages in both cochlea and vestibule were found in EH group(all P<0.001).The area under the curve(AUC)of cochlear or vestibular endolymph/membranous labyrinth area percentage for identifying inner ear EH was 0.999 and 0.985,respectively.Taken 13.64%and 24.13%as the critical value of cochlear or vestibular endolymph,the specificity was 100%and 92.86%,respectively,and the sensitivity was 96.43%and 96.43%,respectively.Conclusion MR long TR 3D real IR was helpful to quantifying inner ear EH.
文摘Objective To observe the value of isotropic volumetric MRI for displaying perineural spread(PNS)of cranial nerve(CN)in nasopharyngeal carcinoma.Methods Eighty-seven patients with pathologically proven nasopharyngeal carcinoma were prospectively enrolled.MR scanning,including three-dimensional liver acquisition with volume acceleration-flexible(3D LAVA_Flex)image,T2WI with fat suppression(T2WI-FS),T1WI,contrast enhancement(CE)T1WI-FS of nasopharynx and neck region were performed.The displaying rates of CN PNS were evaluated and compared between 3D LAVA_Flex and T2WI-FS,T1WI,CE-T1WI-FS at patient level,CN group level and neural level,respectively.Results The displaying rate of CN PNS in all 87 nasopharyngeal carcinoma patients by 3D LAVA_Flex sequence was 49.43%(43/87),higher than that of conventional MRI(30/87,34.48%,P=0.001).Among 59 patients with advanced nasopharyngeal carcinoma diagnosed with conventional sequences,the displaying rate of CN PNS was 71.19%(42/59)by 3D LAVA-Flex sequence,higher than that of conventional MRI(30/59,50.85%,P=0.001).At both patient level and posterior CN level,significant differences of the displaying rate of CN PNS were found between 3D LAVA-Flex sequence and T2WI-FS,T1WI,CE-T1WI-FS,while at CN level,the displaying rates of mandibular nerve PNS,CNⅨ—ⅪPNS in jugular foramen(P<0.05)and CNⅨ—ⅫPNS in carotid space of 3D LAVA_Flex sequence were all significantly higher than that of T2WI-FS,T1WI and CE-T1WI-FS(all P<0.05),of PNS of CNⅢ—Ⅴin cavernous sinus were higher than that of T2WI-FS(P<0.05),while of PNS of hypoglossal nerve were significantly higher than that of T2WI-FS and T1WI(both P<0.05).Conclusion 3D LAVA_Flex sequence could be used to effectively display CN PNS of nasopharyngeal carcinoma.
基金Project(2011JQ028)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2008SK3114,2010SK3113)supported by Hunan Provincial Science&Technology Plan,China+2 种基金Project(B2007086)supported by Science&Research Funds of Hunan Health Department,ChinaProject(12JJ5057)supported by Natural Science Foundation of Hunan Province,ChinaProjects(XCX1119,XCX12073)supported by University Students Innovative Experiment Plan Project of Hunan Agricultural University,China
文摘Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.
