BOLD和DTI在颅内肿瘤中的应用价值
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摘要
为了探讨BOLD及DTI对于区分颅内肿瘤的边界的意义,明确颅内肿瘤与功能区及纤维束的关系,本文回顾性分析了经临床及病理证实的27例颅内肿瘤的常规MRI、BOLD及DTI表现。结果表明:1.常规MRI检查可明确颅内肿瘤内部出血、囊变或坏死情况,但FA图对明确肿瘤各向异性弥散情况的变化明显优于常规MRI检查。2.颅内肿瘤无论胶质瘤或脑膜瘤,其实质区、囊变区、水肿区、水肿周围白质平均FA值相互之间比较均有统计学意义(P<0.05),可根据FA值区分肿瘤实质区、水肿区、水肿周围白质的边界。3. DEC图比FA图能获得更多的纤维束信息及各向异性弥散程度变化的信息。4. DTT图可直接观察颅内肿瘤对周围白质纤维束的损害情况。5. BOLD可清晰显示颅内肿瘤与功能区的关系,为术前制定手术方案提供依据。因而,BOLD联合DTI分析可用来协助制定颅内肿瘤的手术方案以及明确术式,为改善患者术后的生活质量提供帮助。
Intracranial tumors which have high morbidity and disability rate, commonly occurs in central neural system. In fact, neurosurgeons are still looking for a proper way to solve the problem: how to resect the tumor sufficiently, protect the normal nerve tissue effectively, at the same time, improve the patients’prognostic quality of life prominently.
For the past few years, DWI (diffusion weighted imaging), MRS (magnetic resonance spectroscopy), DTI (diffusion tensor imaging) and BOLD (blood oxygen level dependent imaging) developed rapidly. BOLD with both high temporal resolution and high spatial resolution, is able to display the posittion and area of the cortex activation, which can be fused with anatomy imaging correctly. Newly developed magnetic technology, DTI, which is based on DWI, can be realized to timingly and quantitatively analyze the tissue diffusion properties of water molecules in three dimensions. BOLD and DTI can exactly discover whether the cortex activation and the white matter tract are involved in intracranial tumors or not. Imaging study can provide more appropriate selections of surgical approach and techniques for neurosurgeons, help the patients who are suffering from intracranial tumors.
We had studied 27 patients with intracranial tumors. They all underwent conventional MR imaging, BOLD and DTI respectively. The purpose of this article was to study the significance in distinguishing the boundary of the intracranial tumors with BOLD and DTI, to define the relationship between the intracranial tumor and the cortex activation and white matter tract. This study could propose a solution to serve the purpose to decide a surgical approach for surgeons and contribute to improve the patients’quality of life after resection. Methods:
A total of 27 patients with gliomas and meningiomas and 3 healthy volunteers underwent conventional MR imaging (T1WI, T2WI and FLAIR)、diffusion tensor imaging and blood oxygen level dependent imaging, using SEIMENS 3.0T Trio Tim superconductive magnetic resonance imager. Conventional MR imagings (T1WI, T2WI and FLAIR) were performed with FLASH and turbo spin echo sequence (slice thickness: 5.0mm; slice interval: 1.5mm; FOV: 220mm×220mm; T1WI: TR/TE= 440/2.46ms; T2WI: TR/TE= 5000/93ms; FLAIR: TR/TE= 8000/93ms, TI= 2371.5ms). 20 patients underwent enhanced MRI with magnevist as contrast agent (0.2ml/kg). All patients underwent anatomy (t1-mpr-ns-sag-p2-iso) scan (slice thickness: 1.0mm; slice interval: 0.5mm; FOV: 250mm×250mm; TR/TE=2300/2.53ms). Diffusion tensor imaging was performed with a single shot, spin echo, echo-planar, diffusion-weighted pulse sequence(64 different motion probing gradient directions, TR/TE= 5700/93ms, b=0s/mm2 and b= 1000s/mm2, slice thickness: 3mm, slice interval: 0mm, FOV: 230mm×230mm. When underwent blood oxygen level dependent imaging (slice thickness: 3.0mm; slice interval: 0.75mm; FOV: 192mm×192mm; TR/TE= 3000/30ms), patients performed alternative activation, and the data was collected by 6 groups, each group for 30 seconds. We used Neuro 3D software of the workstation to analyse the data. On FA map, 3 or 4 ROIs were chosen, including solid and cystoid portion of the tumor, edema area and the edge of edema, as well as the contralateral normal brain regions were chosen. A statistic analysis was given after calculating the average FA value of different ROIs. Diffusion tensor tractography was reconstructed by“seed method”.
Results:
On conventional MR images: Gliomas were abnormal in signal intensity, with slight mass effect and a slight edema, with low signal in T1WI and high signal in T2WI/FLAIR. When there was cystoid portion in the tumor, it may be lower signal in T1WI and higher signal in T2WI/FLAIR. The tumors’boundary was vague. Gliomas showed slight enhancement, no enhancement, or complicated enhanced signals according to different grades. Meningiomas which showed sharp boundary were round normally with obvious mass effect, and a base attachment to endocranium, with the same signal with gray matter. Enhancement MRI of meningiomas were uniform bright. On FA images, all giomas and edema areas showed very low signal, cystoid portions showed lower signal. All meningiomas showed low signal in the solid portions. The mean FA value of all gliomas’ROIs was significant lower (P<0.05 or P<0.001) than that of normal brain. A decreasing tendency of mean FA value could be observed as follow: edge of edema areas (0.6527±0.1330) was hightest, followed by edema areas (0.2740±0.2304) and solid portions (0.0889±0.0325) then cystoid portions (0.0602±0.0207). The mean FA value of all meningiomas’solid portions and edema areas’ROIs was significant lower(P<0.001) than that of normal brain, but the mean FA value of edge of edema areas was higher than that of normal brain. We think the reason is that the white matter tract near the tumor is compressed, and some fiber tracts are tighter than that of normal. The mean FA value of all intracranial tumors’ROIs had statistical significance (P<0.05) when they were compared with each other. So we can use FA value to distinguish the boundaries of the intracranial tumors. White matter fibers could be well distinguished by different colors on DEC images. We can observe gliomas on DEC images as follow: Solid portions of the gliomas were dark colors, and fiber tracts were vague; cystoid portions were deep dark colors; edema areas were dark colors too; slightly compressed with normal, bright colors beyond edema areas. DEC images show all the meningiomas as follow: solid portions were uneven dark colors, edema areas were dark colors, the boundaries were vague, the rounding fibers were compressed. 5 cases of all gliomas merely involved CST, 3 cases merely involved corpus callosum, and 4 cases involved both CST and corpus callosum. We describe that as follow: Fiber tracts were destruct and discontinuous in the tumors; the fibers nearby were separate and a little discontinuous, their direction were changed for the tumors’compression (accompany with colors changed). 7 cases of all meningiomas merely involved CST, 8 cases involved both CST and corpus callosum. We describe that as follow: Fibers structure was approximately normal in the tumors, but the direction was changed (accompany with colors changed). The compressed fibers were dense or separate. We can conclude that fiber tracts were destruct and discontinuous in gliomas, and fibers near meningiomas were deviated, dense and rare. We can observed in BOLD that: some intracranial tumors didn’t involve the cortex activation at all, so the cortex activations at both sides were symmetry, same area and the signal was consistent. In the article, One case of glioma occurred in the left basal ganglia (glioblastoma, WHO IV grade) had large edema area, and caused the ipsilateral cortex activation reduced. Some meningomas that occurred in cortex activation caused asymmetric of cortex activations, the ipsilateral cortex activation’s position was deviated and configuration changed ( according to the tumors’location, shape, oppression in different directions).
Conclusion:
1. BOLD can display the relationship between the intracranial tumors and the cortex activations, provide more appropriate selections of surgical approach and technique for neurosurgeons by imaging study.
2. DTI proposes a solution to select surgical approach, shows the correlation between the white matter tracts and nearby tumors directly.
3. FA value contributes positively to study the boundaries of the intracranial tumors.
4. The combination of BOLD and DTI is useful for preoperative investigation, especially assisting surgical planning, e.g. deciding on a surgical approach, and also helpful to improve the patients’postoperational quality of life.
Intracranial tumors which have high morbidity and disability rate, commonly occurs in central neural system. In fact, neurosurgeons are still looking for a proper way to solve the problem: how to resect the tumor sufficiently, protect the normal nerve tissue effectively, at the same time, improve the patients’prognostic quality of life prominently.
For the past few years, DWI (diffusion weighted imaging), MRS (magnetic resonance spectroscopy), DTI (diffusion tensor imaging) and BOLD (blood oxygen level dependent imaging) developed rapidly. BOLD with both high temporal resolution and high spatial resolution, is able to display the posittion and area of the cortex activation, which can be fused with anatomy imaging correctly. Newly developed magnetic technology, DTI, which is based on DWI, can be realized to timingly and quantitatively analyze the tissue diffusion properties of water molecules in three dimensions. BOLD and DTI can exactly discover whether the cortex activation and the white matter tract are involved in intracranial tumors or not. Imaging study can provide more appropriate selections of surgical approach and techniques for neurosurgeons, help the patients who are suffering from intracranial tumors.
We had studied 27 patients with intracranial tumors. They all underwent conventional MR imaging, BOLD and DTI respectively. The purpose of this article was to study the significance in distinguishing the boundary of the intracranial tumors with BOLD and DTI, to define the relationship between the intracranial tumor and the cortex activation and white matter tract. This study could propose a solution to serve the purpose to decide a surgical approach for surgeons and contribute to improve the patients’quality of life after resection. Methods:
A total of 27 patients with gliomas and meningiomas and 3 healthy volunteers underwent conventional MR imaging (T1WI, T2WI and FLAIR)、diffusion tensor imaging and blood oxygen level dependent imaging, using SEIMENS 3.0T Trio Tim superconductive magnetic resonance imager. Conventional MR imagings (T1WI, T2WI and FLAIR) were performed with FLASH and turbo spin echo sequence (slice thickness: 5.0mm; slice interval: 1.5mm; FOV: 220mm×220mm; T1WI: TR/TE= 440/2.46ms; T2WI: TR/TE= 5000/93ms; FLAIR: TR/TE= 8000/93ms, TI= 2371.5ms). 20 patients underwent enhanced MRI with magnevist as contrast agent (0.2ml/kg). All patients underwent anatomy (t1-mpr-ns-sag-p2-iso) scan (slice thickness: 1.0mm; slice interval: 0.5mm; FOV: 250mm×250mm; TR/TE=2300/2.53ms). Diffusion tensor imaging was performed with a single shot, spin echo, echo-planar, diffusion-weighted pulse sequence(64 different motion probing gradient directions, TR/TE= 5700/93ms, b=0s/mm2 and b= 1000s/mm2, slice thickness: 3mm, slice interval: 0mm, FOV: 230mm×230mm. When underwent blood oxygen level dependent imaging (slice thickness: 3.0mm; slice interval: 0.75mm; FOV: 192mm×192mm; TR/TE= 3000/30ms), patients performed alternative activation, and the data was collected by 6 groups, each group for 30 seconds. We used Neuro 3D software of the workstation to analyse the data. On FA map, 3 or 4 ROIs were chosen, including solid and cystoid portion of the tumor, edema area and the edge of edema, as well as the contralateral normal brain regions were chosen. A statistic analysis was given after calculating the average FA value of different ROIs. Diffusion tensor tractography was reconstructed by“seed method”.
Results:
On conventional MR images: Gliomas were abnormal in signal intensity, with slight mass effect and a slight edema, with low signal in T1WI and high signal in T2WI/FLAIR. When there was cystoid portion in the tumor, it may be lower signal in T1WI and higher signal in T2WI/FLAIR. The tumors’boundary was vague. Gliomas showed slight enhancement, no enhancement, or complicated enhanced signals according to different grades. Meningiomas which showed sharp boundary were round normally with obvious mass effect, and a base attachment to endocranium, with the same signal with gray matter. Enhancement MRI of meningiomas were uniform bright. On FA images, all giomas and edema areas showed very low signal, cystoid portions showed lower signal. All meningiomas showed low signal in the solid portions. The mean FA value of all gliomas’ROIs was significant lower (P<0.05 or P<0.001) than that of normal brain. A decreasing tendency of mean FA value could be observed as follow: edge of edema areas (0.6527±0.1330) was hightest, followed by edema areas (0.2740±0.2304) and solid portions (0.0889±0.0325) then cystoid portions (0.0602±0.0207). The mean FA value of all meningiomas’solid portions and edema areas’ROIs was significant lower(P<0.001) than that of normal brain, but the mean FA value of edge of edema areas was higher than that of normal brain. We think the reason is that the white matter tract near the tumor is compressed, and some fiber tracts are tighter than that of normal. The mean FA value of all intracranial tumors’ROIs had statistical significance (P<0.05) when they were compared with each other. So we can use FA value to distinguish the boundaries of the intracranial tumors. White matter fibers could be well distinguished by different colors on DEC images. We can observe gliomas on DEC images as follow: Solid portions of the gliomas were dark colors, and fiber tracts were vague; cystoid portions were deep dark colors; edema areas were dark colors too; slightly compressed with normal, bright colors beyond edema areas. DEC images show all the meningiomas as follow: solid portions were uneven dark colors, edema areas were dark colors, the boundaries were vague, the rounding fibers were compressed. 5 cases of all gliomas merely involved CST, 3 cases merely involved corpus callosum, and 4 cases involved both CST and corpus callosum. We describe that as follow: Fiber tracts were destruct and discontinuous in the tumors; the fibers nearby were separate and a little discontinuous, their direction were changed for the tumors’compression (accompany with colors changed). 7 cases of all meningiomas merely involved CST, 8 cases involved both CST and corpus callosum. We describe that as follow: Fibers structure was approximately normal in the tumors, but the direction was changed (accompany with colors changed). The compressed fibers were dense or separate. We can conclude that fiber tracts were destruct and discontinuous in gliomas, and fibers near meningiomas were deviated, dense and rare. We can observed in BOLD that: some intracranial tumors didn’t involve the cortex activation at all, so the cortex activations at both sides were symmetry, same area and the signal was consistent. In the article, One case of glioma occurred in the left basal ganglia (glioblastoma, WHO IV grade) had large edema area, and caused the ipsilateral cortex activation reduced. Some meningomas that occurred in cortex activation caused asymmetric of cortex activations, the ipsilateral cortex activation’s position was deviated and configuration changed ( according to the tumors’location, shape, oppression in different directions).
Conclusion:
1. BOLD can display the relationship between the intracranial tumors and the cortex activations, provide more appropriate selections of surgical approach and technique for neurosurgeons by imaging study.
2. DTI proposes a solution to select surgical approach, shows the correlation between the white matter tracts and nearby tumors directly.
3. FA value contributes positively to study the boundaries of the intracranial tumors.
4. The combination of BOLD and DTI is useful for preoperative investigation, especially assisting surgical planning, e.g. deciding on a surgical approach, and also helpful to improve the patients’postoperational quality of life.
引文
[1]何立岩,伍建林.磁共振脑功能成像的原理及研究进展.中国临床医学影像杂志, 2002,13,(3):210-212.
[2] Roberts TP, Ferrari P, Perry D, et al. Presurgical mapping with magnetic source imaging: comparisons with intraoperative findings. Brain Tumor Pathol, 2000,17(2):57-64.
[3] Majos A, Tybor K, Stefanczyk L, et al. Cortical mapping by functional magnetic resonance imaging in patients with brain tumors. Eur Radiol, 2005,15 (6): 1148-1158.
[4] Schulder M, Mildjian JA, Liu WC, et al. Functional image-guided surgery of intracranial tumors located in or near the sensorimoter cortex [J]. Neurosurg, 1998,89(9):412-428.
[5] Holodny AI, Schulder M, Liu WC, et al. Decreased BOLD functional MR activation of the motor and sensory cortices adjacent to a glioblastoma multiforme: implications for image-guided neurosurgery. AJNR, 1999,20(4): 609-612.
[6] Lurito JT, Lowe MJ, Sartorius C, et al. Comparison of fMRI and intraoperative direct cortical stimulation in localization of receptive language areas. JCAT,2000,24(1):99-105.
[7]叶建华.脑血氧水平依赖性MR功能成像原理及其在神经外科中手术的应用研究.临床和实验医学杂志, 2006,5(1):54-74.
[8] Macdonell RA, Jackson GD, Curatolo JM, et al. Motor cortex localization using functional MRI and transcranial magnetic stimulation [J]. Neurology,1999,53(7):1462-1467.
[9] Bookheimer SY, Dapretto M, Karmarkar U. Functional MRI in children with epilepsy [J]. DevNeurosci,1999,21(3-5):191-199.
[10]张怀岭,张宏杰,包尚联.血氧水平依赖磁共振脑功能成像.北京生物医学工程, 2004,23(2):150-151.
[11]尚寒冰,赵卫国.磁共振功能成像在颅内肿瘤诊治中的应用进展.国际神经病学神经外科学杂志, 2008,35(4):343-346.
[12] Witwer BP, Moftakhar R, Hasan KM, et al. Diffusion-tensor imaging of white matter tracts in patients with cerebral neoplasm. [J]. Neurosurg, 2002,97(3):568-575.
[13]何光武,沈天真,陈星荣.大脑白质纤维磁共振弥散张量纤维束成像初步研究.中华医学杂志, 2005, 85(39): 2775-2779.
[14] Smits M, Vernooij MW, Wielopolski PA, et al. Incorporating functional MR imaging into diffusion tensor tractography in the preoperative assessment of the corticospinal tract in patients with brain tumors. AJNR Am J Neuroradiol, 2007,28(7):1354-1361.
[15]何光武,刘源香.大脑磁共振弥散张量成像研究进展.中国中西医结合影像学杂志.2006,4 ,4(2):131-133.
[16]盛复庚.磁共振弥散张量成像的基本原理和临床应用.中国医学影像学杂志, 2003,11,(1):56-58.
[17]吴劲松,周良辅,洪汛宁,毛颖,杜固宏.磁共振弥散张量成像在涉及锥体束的脑肿瘤神经导航术中的应用.中华外科杂志,2003,41(9): 266-666.
[18]姜晓峰,付先明,潘仲林,孟晓梅,汪业汉、凌至培、吴津民、牛朝诗、李光群.功能性磁共振辅助导航手术治疗运动功能区病变.首届全国功能影像学和神经信息学研讨会论文汇编, 179-182.
[19] Jiang Y, Hsu EW. Accelerating MR diffusion tensor imaging via filtered reduced encoding projection-reconstruction [J]. Magn Reson Med, 2005,53(1):93-102.
[1] Ogawa S, Lee TM, Nayak AS, et al. Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields [J]. Magn Reson Med, 1990,14(1):68-78.
[2]何光武,刘源香.大脑磁共振弥散张量成像研究进展.中国中西医结合影像学杂志, 2006,4,4(2):131-133.
[3] Pierpaoli C, Jezzard P, Basser PJ, et al. Diffusion tensor MR imaging of the human brain [J]. Radiology, 1996,201(3):637-648.
[4] Shimony JS, McKinstry RC, Akbudak E, et al. Quantitative diffusion-tensor anisotropy brain MR imaging: normative human data and anatomic analysis [J]. Radiology, 1999,212(3):770-784.
[5]曾洪武.磁共振扩散加权与弥散张量成像原理分析及比较.中国医学影像技术, 2005,21(12):1945-1947.
[6] Le Bihan D, Mangin JF, Poupon C, et al. Diffusion tensor imaging: concepts and application [J]. J Magn Reson Imaging, 2001,13(14): 534- 546.
[7]钟维佳,赵建农,谢微波,邢海芳,陈维娟.磁共振扩散张量成像对正常人脑结构的显示及各向异性研究[J].临床放射学杂志, 2006,25(9): 807-811.
[8] Holodny AI, Ollenschlager M. Diffusion imaging in brain tumors [J]. Neuroimaging Clin of N Am, 2002,12(1):107-124.
[9] Ramnani N, Behrens TE, Penny W, et al. New approaches for exploring anatomical and functional connectivity in the human brain [J]. Biol Psychiatry, 2004,56(9):613-619.
[10]吴仁华.磁共振弥散加权像对早期脑梗塞的诊断价值[J].中华内科杂志, 1998,37(2):116-118.
[11] Bagley LJ, Grossman RI, Judy KD, et al. Gliomas: correlation of magnetic susceptibility artifact with histologic grade [J]. Radiology, 1997,202(2):511-516.
[12] Wieshmann UC, Symms MR, Parker GJ, et al. Diffusion tensor imaging demonstrates deviation of fibres in normal appearing white matter adjacent to a brain tumour [J]. J Neurol Neurosurg psychiatry, 2000,68(4):501-503.
[13] Kelly PJ, Daumas-Duport C, Kispert DB, et al. Imaging-based stereotaxic serial biopsies in untreated intracranial glial neoplasms [J]. J Neurosurg, 1987,66(6):865-874.
[2] Roberts TP, Ferrari P, Perry D, et al. Presurgical mapping with magnetic source imaging: comparisons with intraoperative findings. Brain Tumor Pathol, 2000,17(2):57-64.
[3] Majos A, Tybor K, Stefanczyk L, et al. Cortical mapping by functional magnetic resonance imaging in patients with brain tumors. Eur Radiol, 2005,15 (6): 1148-1158.
[4] Schulder M, Mildjian JA, Liu WC, et al. Functional image-guided surgery of intracranial tumors located in or near the sensorimoter cortex [J]. Neurosurg, 1998,89(9):412-428.
[5] Holodny AI, Schulder M, Liu WC, et al. Decreased BOLD functional MR activation of the motor and sensory cortices adjacent to a glioblastoma multiforme: implications for image-guided neurosurgery. AJNR, 1999,20(4): 609-612.
[6] Lurito JT, Lowe MJ, Sartorius C, et al. Comparison of fMRI and intraoperative direct cortical stimulation in localization of receptive language areas. JCAT,2000,24(1):99-105.
[7]叶建华.脑血氧水平依赖性MR功能成像原理及其在神经外科中手术的应用研究.临床和实验医学杂志, 2006,5(1):54-74.
[8] Macdonell RA, Jackson GD, Curatolo JM, et al. Motor cortex localization using functional MRI and transcranial magnetic stimulation [J]. Neurology,1999,53(7):1462-1467.
[9] Bookheimer SY, Dapretto M, Karmarkar U. Functional MRI in children with epilepsy [J]. DevNeurosci,1999,21(3-5):191-199.
[10]张怀岭,张宏杰,包尚联.血氧水平依赖磁共振脑功能成像.北京生物医学工程, 2004,23(2):150-151.
[11]尚寒冰,赵卫国.磁共振功能成像在颅内肿瘤诊治中的应用进展.国际神经病学神经外科学杂志, 2008,35(4):343-346.
[12] Witwer BP, Moftakhar R, Hasan KM, et al. Diffusion-tensor imaging of white matter tracts in patients with cerebral neoplasm. [J]. Neurosurg, 2002,97(3):568-575.
[13]何光武,沈天真,陈星荣.大脑白质纤维磁共振弥散张量纤维束成像初步研究.中华医学杂志, 2005, 85(39): 2775-2779.
[14] Smits M, Vernooij MW, Wielopolski PA, et al. Incorporating functional MR imaging into diffusion tensor tractography in the preoperative assessment of the corticospinal tract in patients with brain tumors. AJNR Am J Neuroradiol, 2007,28(7):1354-1361.
[15]何光武,刘源香.大脑磁共振弥散张量成像研究进展.中国中西医结合影像学杂志.2006,4 ,4(2):131-133.
[16]盛复庚.磁共振弥散张量成像的基本原理和临床应用.中国医学影像学杂志, 2003,11,(1):56-58.
[17]吴劲松,周良辅,洪汛宁,毛颖,杜固宏.磁共振弥散张量成像在涉及锥体束的脑肿瘤神经导航术中的应用.中华外科杂志,2003,41(9): 266-666.
[18]姜晓峰,付先明,潘仲林,孟晓梅,汪业汉、凌至培、吴津民、牛朝诗、李光群.功能性磁共振辅助导航手术治疗运动功能区病变.首届全国功能影像学和神经信息学研讨会论文汇编, 179-182.
[19] Jiang Y, Hsu EW. Accelerating MR diffusion tensor imaging via filtered reduced encoding projection-reconstruction [J]. Magn Reson Med, 2005,53(1):93-102.
[1] Ogawa S, Lee TM, Nayak AS, et al. Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields [J]. Magn Reson Med, 1990,14(1):68-78.
[2]何光武,刘源香.大脑磁共振弥散张量成像研究进展.中国中西医结合影像学杂志, 2006,4,4(2):131-133.
[3] Pierpaoli C, Jezzard P, Basser PJ, et al. Diffusion tensor MR imaging of the human brain [J]. Radiology, 1996,201(3):637-648.
[4] Shimony JS, McKinstry RC, Akbudak E, et al. Quantitative diffusion-tensor anisotropy brain MR imaging: normative human data and anatomic analysis [J]. Radiology, 1999,212(3):770-784.
[5]曾洪武.磁共振扩散加权与弥散张量成像原理分析及比较.中国医学影像技术, 2005,21(12):1945-1947.
[6] Le Bihan D, Mangin JF, Poupon C, et al. Diffusion tensor imaging: concepts and application [J]. J Magn Reson Imaging, 2001,13(14): 534- 546.
[7]钟维佳,赵建农,谢微波,邢海芳,陈维娟.磁共振扩散张量成像对正常人脑结构的显示及各向异性研究[J].临床放射学杂志, 2006,25(9): 807-811.
[8] Holodny AI, Ollenschlager M. Diffusion imaging in brain tumors [J]. Neuroimaging Clin of N Am, 2002,12(1):107-124.
[9] Ramnani N, Behrens TE, Penny W, et al. New approaches for exploring anatomical and functional connectivity in the human brain [J]. Biol Psychiatry, 2004,56(9):613-619.
[10]吴仁华.磁共振弥散加权像对早期脑梗塞的诊断价值[J].中华内科杂志, 1998,37(2):116-118.
[11] Bagley LJ, Grossman RI, Judy KD, et al. Gliomas: correlation of magnetic susceptibility artifact with histologic grade [J]. Radiology, 1997,202(2):511-516.
[12] Wieshmann UC, Symms MR, Parker GJ, et al. Diffusion tensor imaging demonstrates deviation of fibres in normal appearing white matter adjacent to a brain tumour [J]. J Neurol Neurosurg psychiatry, 2000,68(4):501-503.
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