髓外硬膜下单发神经纤维瘤的MRI诊断
作者：林曰增
单位：第一军医大学南方医院影像诊断中心，广州，510515
关键词：脊髓；神经纤维瘤；磁共振成像
髓外硬膜下单发神经纤维瘤的MRI诊断摘要：神经纤维瘤由雪旺氏细胞和纤维母细胞组成，常伴随神经纤维瘤病。本文探讨了经手术和病理证实的8例髓外硬膜下单发神经纤维瘤的MR表现。这些病变典型的MR表现为T1加权成像与脊髓信号相比呈等或低信号，T2加权呈高信号。T2加权信号高于脑脊液的区域提示囊性区。3例行Gd-DTPA增强T1加权成像，未强化区显示囊变。8例中3例显示肿瘤囊变。3例通过椎间孔延伸至椎管和脊椎周围形成“哑铃”状肿块，这些肿块通常认为是神经源性的。MRI因为能直接显示脊髓且无创伤性，已成为评估脊髓肿瘤的最有效的方法，。静脉内顺磁性造影剂强化扫描能进一步显示这类病变。
, http://www.100md.com
中图分类号：R445.2; R739.42
MR imaging diagnosis of solitary intradural extramedullary neurofibroma Lin Yuezeng
Imaging Diagnostic Centre, Nanfang Hospital, First Military Medical University, Guangzhou, 510515
Abstract: Neurofibroma is composed of Schwann cells and fibroblasts and universally seen in multiples with von Recklinghausen,s neurofibromatosis. This paper reviews the MR finding in 8 patients with surgically and pathologically proved solitary intradural extramedullary neurofibroma. Typically, signals on T1-weighted images of these lesions appeared hypointense to isointense relative to the spinal cord. Tumors had signal intensity than that of the spinal cord on T2-weighted images (T2WI). Focal areas of even greater hyperintensity than that of CSF on T2WI often corresponded to cystic portion. Gd-DTPA enhanced T1WI were performed in 3 patients. The unenhanced areas demonstrated cystic degeneration. Tumoral cysts were displayed in 3 cases of the eight cases. Three tumors extended into the vertebral canal and paraspinal spaces through the intervertebral foramen and formed the “dumbbell-shaped” masses which are usually thought to be of neurogenic origin. In summary, MR imaging has become the single most effective modality for the evaluation of spinal neoplasms by virtue of its ability to image the spinal cord directly and noninvasively. Intravenous paramagnetic contrast enhancement also may prove extremely useful in further delineating such lesions.
, 百拇医药
Key words: spinal cord; neurofibroma; magnetic resonance image
椎管内神经纤维瘤常为多发，且常合并神经纤维瘤病[1]。本文报道术前行MR检查，手术及病理证实的8例髓外硬膜下单发神经纤维瘤。
1 材料和方法
8例中，男性5例，女性3例；年龄32～60岁，平均45岁。主要临床症状为肢体无力、麻木、颈痛、腰痛，严重者肢体肌萎缩，大便困难。
使用超导型MR仪，工作场强0.35T，SE序列，多回波技术，矩阵256×256，层厚5.0 mm，行矢状面T1加权(TR/TE=500 ms/30 ms)、矢状面T2加权(TR/TE=2000 ms/40～80 ms)。常规横断面T1加权(TR/TE=500 ms/30 ms)。3例行增强T1加权矢状面及横断面扫描，使用顺磁性造影剂Gd—DTPA，剂量0.1 mmol/kg，静脉注射。
, 百拇医药
2 结果
病变分布：颈段4例，颈胸段1例，胸段2例，腰骶段1例。病变长度1～6个椎体(包括椎间隙)不等，平均2.5个椎体高度。位于脊髓平面7例，均见肿瘤上下侧蛛网膜下腔扩大及脊髓向对侧移位。肿瘤位于硬膜内外3例，呈“哑铃”状(见图1A～C。压迫椎体后缘1例，钙化1例，囊变3例。T1加权呈低、等、低等混合信号分别为3例、4例及1例。T2加权成像呈高信号7例，其中信号强度等于和高于脑脊液的分别为1例，高低混合信号1例。3例增强T1加权扫描，均匀强化、无强化及环状强化各1例。
, 百拇医药
图1 A～C颈6～7水平神经纤维瘤MRI
Fig. 1 A～C MRI of neurofibroma at the level of C6-7
Sagittal MR images (A) (SE T1-Weighted—TR500/TE40) and (B) (SE T2-weighted—TR2000/TE80) demonstrate a mass compressing the spinal cord. This is of low intensity on the T1-weighted scan and of high intensity on the T2-weighted scan compared with spinal cord. Axial MR image (C) clearly displays increase of signal intensity of the tumor and also shows laterally posterior lying tumor and the displaced cord.
, http://www.100md.com
3 结论
神经纤维瘤起源于神经纤维母细胞，组织学上可见Schwann细胞、纤维母细胞、有髓鞘或无髓鞘的神经纤维等多种成分存在。 神经鞘瘤起源于神经鞘膜的雪旺氏细胞，又称雪旺氏细胞瘤。两者的主要成分均是Schwann细胞和纤维母细胞，神经纤维瘤以纤维母细胞为主要成份，而神经鞘瘤以鞘细胞为主要成份。二者在组织培养中均可产生胶原纤维及网状纤维，神经纤维瘤产生上述两种纤维更明显。超微结构研究证明，两者均来自Schwann细胞。两者统称为神经源性肿瘤，它与脊膜瘤是最常见的髓外硬膜下肿瘤，约占成年人原发椎管内肿瘤的一半[1，2]。
定位诊断：本组8例，均定位正确，定位正确率达100%。位于脊髓节段的髓外硬膜下肿瘤，均可使肿瘤上下端的蛛网膜下腔扩大，脊髓向对侧移位。
定性诊断：神经纤维瘤与神经鞘瘤同属神经源性肿瘤，两者组织结构相仿，病理上常混合存在，为同源性，MR表现相似。与正常脊髓信号比较，T1加权为低或等信号，T2加权为高信号[3～5]。T2加权信号高于脑脊液(CSF)时，提示肿瘤囊变。文献报道[1]，1/6的肿瘤位于硬膜内、外，呈“哑铃”状。本组8例中，3例肿瘤呈“哑铃”状，占37.8%，高于文献报道。MRI是显示此类肿瘤的最理想成像方法。由于此类肿瘤常伴发肿瘤内囊变或坏死，因此，其MR信号有时是不均匀的。由于此类肿瘤缺乏血脑屏障。再加上肿瘤血供丰富，增强后T1加权的表现不同，均匀强化、不均匀强化或环状强化，取决于囊变的程度。本组发生囊变3例，占37.8%。本组位于腰1 ～骶1的腰骶段肿瘤术前MR诊断为“L1～S1椎管内偏良性肿瘤”；颈胸段1例诊断为“C6～T1髓外硬膜下神经纤维瘤”；其余均诊断为“髓外硬膜下神经源性肿瘤”。
, http://www.100md.com
尽管神经鞘瘤比神经纤维瘤更易发生囊变和向椎管内、外生长而呈“哑铃”状，但两者鉴别仍有困难。
以往椎管肿瘤的主要检查方法为X线平片、椎管碘水造影、CT平扫及椎管碘水造影CT扫描，现在，MR以其无创伤性、无骨伪影、多平面成像、不需椎管内注入造影剂、直接显示肿瘤本身信号及其与周围结构的关系、定位定性正确率高、以及顺磁性造影剂Gd-DTPA的应用等优点[3,4]，开始取代传统检查技术。
作者简介：林日增，男，1964年出生；主治医师，硕士研究生；发表论文20余篇；电话85142086
参考文献
1 Zimmerman RA, Bilaniuk LT. Imaging of tumors of the spinal canal and cord. Radiol Clin North Am, 1988,26(5):965
, 百拇医药
2 Masaryk TJ. Neoplastic disease of the spine. Radiol Clin North Am, 1991,29(4):829
3 Scotti G, Scialfa G, Colombo N et al. MR imaging of intradural extramedullary tumors of the cervical spine. JCAT, 1985,9(6):1037
4 Takemoto K, Matsumura Y, Hashimoto H et al. MR imaging of intraspinal tumors – capability in histological differentiation and compartmentali-zation of extramedullary tumors. Neuroradiology, 1988,30(4):303
5 Demachi H, Takashima T, Kadoya M et al. MR imaging of spinal neurinoma with pathological correlation. JCAT, 1990,14(2):250
(收稿日期：1998-09-16), http://www.100md.com
单位：第一军医大学南方医院影像诊断中心，广州，510515
关键词：脊髓；神经纤维瘤；磁共振成像
髓外硬膜下单发神经纤维瘤的MRI诊断摘要：神经纤维瘤由雪旺氏细胞和纤维母细胞组成，常伴随神经纤维瘤病。本文探讨了经手术和病理证实的8例髓外硬膜下单发神经纤维瘤的MR表现。这些病变典型的MR表现为T1加权成像与脊髓信号相比呈等或低信号，T2加权呈高信号。T2加权信号高于脑脊液的区域提示囊性区。3例行Gd-DTPA增强T1加权成像，未强化区显示囊变。8例中3例显示肿瘤囊变。3例通过椎间孔延伸至椎管和脊椎周围形成“哑铃”状肿块，这些肿块通常认为是神经源性的。MRI因为能直接显示脊髓且无创伤性，已成为评估脊髓肿瘤的最有效的方法，。静脉内顺磁性造影剂强化扫描能进一步显示这类病变。
, http://www.100md.com
中图分类号：R445.2; R739.42
MR imaging diagnosis of solitary intradural extramedullary neurofibroma Lin Yuezeng
Imaging Diagnostic Centre, Nanfang Hospital, First Military Medical University, Guangzhou, 510515
Abstract: Neurofibroma is composed of Schwann cells and fibroblasts and universally seen in multiples with von Recklinghausen,s neurofibromatosis. This paper reviews the MR finding in 8 patients with surgically and pathologically proved solitary intradural extramedullary neurofibroma. Typically, signals on T1-weighted images of these lesions appeared hypointense to isointense relative to the spinal cord. Tumors had signal intensity than that of the spinal cord on T2-weighted images (T2WI). Focal areas of even greater hyperintensity than that of CSF on T2WI often corresponded to cystic portion. Gd-DTPA enhanced T1WI were performed in 3 patients. The unenhanced areas demonstrated cystic degeneration. Tumoral cysts were displayed in 3 cases of the eight cases. Three tumors extended into the vertebral canal and paraspinal spaces through the intervertebral foramen and formed the “dumbbell-shaped” masses which are usually thought to be of neurogenic origin. In summary, MR imaging has become the single most effective modality for the evaluation of spinal neoplasms by virtue of its ability to image the spinal cord directly and noninvasively. Intravenous paramagnetic contrast enhancement also may prove extremely useful in further delineating such lesions.
, 百拇医药
Key words: spinal cord; neurofibroma; magnetic resonance image
椎管内神经纤维瘤常为多发，且常合并神经纤维瘤病[1]。本文报道术前行MR检查，手术及病理证实的8例髓外硬膜下单发神经纤维瘤。
1 材料和方法
8例中，男性5例，女性3例；年龄32～60岁，平均45岁。主要临床症状为肢体无力、麻木、颈痛、腰痛，严重者肢体肌萎缩，大便困难。
使用超导型MR仪，工作场强0.35T，SE序列，多回波技术，矩阵256×256，层厚5.0 mm，行矢状面T1加权(TR/TE=500 ms/30 ms)、矢状面T2加权(TR/TE=2000 ms/40～80 ms)。常规横断面T1加权(TR/TE=500 ms/30 ms)。3例行增强T1加权矢状面及横断面扫描，使用顺磁性造影剂Gd—DTPA，剂量0.1 mmol/kg，静脉注射。
, 百拇医药
2 结果
病变分布：颈段4例，颈胸段1例，胸段2例，腰骶段1例。病变长度1～6个椎体(包括椎间隙)不等，平均2.5个椎体高度。位于脊髓平面7例，均见肿瘤上下侧蛛网膜下腔扩大及脊髓向对侧移位。肿瘤位于硬膜内外3例，呈“哑铃”状(见图1A～C。压迫椎体后缘1例，钙化1例，囊变3例。T1加权呈低、等、低等混合信号分别为3例、4例及1例。T2加权成像呈高信号7例，其中信号强度等于和高于脑脊液的分别为1例，高低混合信号1例。3例增强T1加权扫描，均匀强化、无强化及环状强化各1例。
, 百拇医药
图1 A～C颈6～7水平神经纤维瘤MRI
Fig. 1 A～C MRI of neurofibroma at the level of C6-7
Sagittal MR images (A) (SE T1-Weighted—TR500/TE40) and (B) (SE T2-weighted—TR2000/TE80) demonstrate a mass compressing the spinal cord. This is of low intensity on the T1-weighted scan and of high intensity on the T2-weighted scan compared with spinal cord. Axial MR image (C) clearly displays increase of signal intensity of the tumor and also shows laterally posterior lying tumor and the displaced cord.
, http://www.100md.com
3 结论
神经纤维瘤起源于神经纤维母细胞，组织学上可见Schwann细胞、纤维母细胞、有髓鞘或无髓鞘的神经纤维等多种成分存在。 神经鞘瘤起源于神经鞘膜的雪旺氏细胞，又称雪旺氏细胞瘤。两者的主要成分均是Schwann细胞和纤维母细胞，神经纤维瘤以纤维母细胞为主要成份，而神经鞘瘤以鞘细胞为主要成份。二者在组织培养中均可产生胶原纤维及网状纤维，神经纤维瘤产生上述两种纤维更明显。超微结构研究证明，两者均来自Schwann细胞。两者统称为神经源性肿瘤，它与脊膜瘤是最常见的髓外硬膜下肿瘤，约占成年人原发椎管内肿瘤的一半[1，2]。
定位诊断：本组8例，均定位正确，定位正确率达100%。位于脊髓节段的髓外硬膜下肿瘤，均可使肿瘤上下端的蛛网膜下腔扩大，脊髓向对侧移位。
定性诊断：神经纤维瘤与神经鞘瘤同属神经源性肿瘤，两者组织结构相仿，病理上常混合存在，为同源性，MR表现相似。与正常脊髓信号比较，T1加权为低或等信号，T2加权为高信号[3～5]。T2加权信号高于脑脊液(CSF)时，提示肿瘤囊变。文献报道[1]，1/6的肿瘤位于硬膜内、外，呈“哑铃”状。本组8例中，3例肿瘤呈“哑铃”状，占37.8%，高于文献报道。MRI是显示此类肿瘤的最理想成像方法。由于此类肿瘤常伴发肿瘤内囊变或坏死，因此，其MR信号有时是不均匀的。由于此类肿瘤缺乏血脑屏障。再加上肿瘤血供丰富，增强后T1加权的表现不同，均匀强化、不均匀强化或环状强化，取决于囊变的程度。本组发生囊变3例，占37.8%。本组位于腰1 ～骶1的腰骶段肿瘤术前MR诊断为“L1～S1椎管内偏良性肿瘤”；颈胸段1例诊断为“C6～T1髓外硬膜下神经纤维瘤”；其余均诊断为“髓外硬膜下神经源性肿瘤”。
, http://www.100md.com
尽管神经鞘瘤比神经纤维瘤更易发生囊变和向椎管内、外生长而呈“哑铃”状，但两者鉴别仍有困难。
以往椎管肿瘤的主要检查方法为X线平片、椎管碘水造影、CT平扫及椎管碘水造影CT扫描，现在，MR以其无创伤性、无骨伪影、多平面成像、不需椎管内注入造影剂、直接显示肿瘤本身信号及其与周围结构的关系、定位定性正确率高、以及顺磁性造影剂Gd-DTPA的应用等优点[3,4]，开始取代传统检查技术。
作者简介：林日增，男，1964年出生；主治医师，硕士研究生；发表论文20余篇；电话85142086
参考文献
1 Zimmerman RA, Bilaniuk LT. Imaging of tumors of the spinal canal and cord. Radiol Clin North Am, 1988,26(5):965
, 百拇医药
2 Masaryk TJ. Neoplastic disease of the spine. Radiol Clin North Am, 1991,29(4):829
3 Scotti G, Scialfa G, Colombo N et al. MR imaging of intradural extramedullary tumors of the cervical spine. JCAT, 1985,9(6):1037
4 Takemoto K, Matsumura Y, Hashimoto H et al. MR imaging of intraspinal tumors – capability in histological differentiation and compartmentali-zation of extramedullary tumors. Neuroradiology, 1988,30(4):303
5 Demachi H, Takashima T, Kadoya M et al. MR imaging of spinal neurinoma with pathological correlation. JCAT, 1990,14(2):250
(收稿日期：1998-09-16), http://www.100md.com