四肢软组织神经鞘瘤的MRI诊断

目的 探讨MRI对四肢软组织神经鞘瘤的诊断价值.方法 回顾性分析12例经手术病理证实的四肢软组织神经鞘瘤的MR影像资料.全部病例均行常规MR扫描,应用T1WI、T2WI及脂肪抑制PDWI序列做轴面、冠状面和矢状面扫描,其中9例行T1WI增强扫描.结果 12例均表现为边界清楚的纺锤形或椭圆形肿块,沿神经走行方向生长,其中单发9例,多发3例.在T1WI呈稍高信号6例,等信号4例,低信号2例.在T2WI及PDWI像上12例均呈不均质高信号.5例可见靶征,7例可见神经出入征,4例可见脂肪分离征,2例同时出现以上3种征象.结论 四肢软组织神经鞘瘤的典型MRI征象是与神经走行一致的椭圆形肿块,T2WI呈不均质高信号,T1WI多呈稍高信号,边界清楚.靶征、神经出入征、脂肪分离征的存在有助于神经鞘瘤的诊断.     

MRI在臂丛神经非创伤性病变中的应用

目的 探讨MRI在常见臂丛神经非创伤性病变中的应用价值.方法 回顾性分析27例累及臂丛神经的非创伤性病变,男10例、女17例,年龄22 ～70岁.其中神经纤维瘤病2例、神经鞘瘤8例、转移瘤3例、放射性臂丛神经炎2例、多灶性运动性神经病(MMN)1例、下干型胸廓出口综合征(TOS)11例.治疗前患者均行MR平扫检查,其中8例同时行Gd-DTPA增强检查.结果 2例神经纤维瘤病见肿瘤沿臂丛神经走行生长,呈梭形、串珠状,并见累及椎管内神经根丝,病灶T1WI呈等稍低信号,T2WI不均匀高信号,增强后不均匀强化.8例神经鞘瘤表现为偏向神经一侧生长的梭形肿块,边界清晰,T1WI呈低信号或不均匀高信号,T2WI呈不均匀高信号,其中3例见有囊变,增强后不均匀强化.3例转移瘤中2例表现为臂丛神经周围的多发肿块影,1例表现为肿瘤组织弥漫浸润臂丛神经及周围组织.2例放射性神经炎表现为臂丛神经弥漫性增粗,短时反转恢复序列(STIR)信号增高,臂丛神经周围结构清晰,无肿块形成.1例MMN表现为臂丛神经增粗、STIR序列信号增高.11例下干型TOS表现为第8颈椎、第1胸椎神经根及下干的弓形抬高,神经增粗,STIR序列信号增高,8例伴锁骨下动脉抬高,1例显示为颈肋末端占位压迫臂丛神经.结论 MRI可清晰显示常见臂丛神经非创伤性病变的部位、累及范围及与邻近组织结构的关系,为临床诊疗提供可靠信息.     

外周恶性神经鞘膜瘤的影像学表现

目的:总结分析外周恶性神经鞘膜瘤的影像学表现,提高鉴别诊断能力。方法:回顾性分析11例经手术或病理证实的恶性神经鞘膜瘤的影像学表现,并与手术病理对照分析,11例中行CT检查3例,行MRI检查4例,CT和MRI均检查4例。结果:CT平扫表现为等、低混合密度软组织肿块影,形态不规则,病灶边缘较光整2例,边缘毛糙5例。CT增强扫描呈不均匀强化,坏死区不强化,网格样强化2例,不均匀强化5例。T1WI呈等、略低信号,内见局灶性长T1信号影;T2WI序列以略高信号为主,内见局灶性长T2信号,周围软组织见片状浸润高信号;MRI增强扫描呈不均匀强化。结论:恶性外周神经鞘膜瘤的CT和MRI表现具有一定的特征性。     

恶性外周神经鞘膜瘤的CT和MRI表现

目的回顾性分析恶性外周神经鞘膜瘤的CT和MRI表现,提高对该病的诊断准确性。方法搜集恶性外周神经鞘膜瘤病人12例,术前均进行了CT或MRI检查。结果CT表现平扫上为等、低密度混合的软组织肿块影,外形不规则,边界清楚(n=9)或模糊(n=3);增强扫描时呈不均性强化,坏死区不强化。MRI表现边界模糊,信号混杂。T1WI序列上多与肌肉等信号(n=11),内示局灶性长T1信号影;T2WI抑脂序列上以略高信号为主,边界清楚(n=2)或模糊(n=10),内示局灶性长T2信号,周围软组织浸润表现为片状高信号;增强扫描时呈不均性强化。结论恶性外周神经鞘膜瘤的CT和MRI表现具有一定的特征性。     

椎管内髓外硬膜下肿瘤的MRI诊断

目的：探讨MRI对椎管内髓外硬膜下肿瘤的诊断价值以及与髓硬膜外肿瘤的鉴别。资料与方法：分析经手术病理证实的10例髓硬膜下肿瘤的MRI表现。结果：MRI定位正确率100％。5例神经鞘瘤T1WI呈略高于脊髓信号，增强扫描后肿瘤信号呈中高程度强化，3例见有神经孔扩大，其中1例位于腰骶部椎管内，呈串珠状，2例神经纤维瘤与神经鞘瘤信号相仿，2例脊膜瘤T1WI呈低或等信号，T2WI呈高或等信号，增强扫描呈明显的异常强化，1例脂肪瘤T1WI及T2WI均呈略高信号，增强扫描后无明显强化。结论：根据椎管内髓外硬膜下原发肿瘤的MR表现，可准确定位并可推测其病理类型。     

椎管内神经鞘瘤的低场MRI诊断

目的:探讨椎管内神经鞘瘤的低场MRI表现及诊断价值。方法:搜集12例经手术病理证实的椎管内神经鞘瘤,重点分析其MRI特点及发病部位。结果:本组病例肿瘤均为单发,T1WI肿瘤呈低或等信号,T2WI呈高信号,增强后显著强化,12例肿瘤病理均无钙化。MRI对椎管内神经鞘瘤定位诊断符合率100%,定性诊断符合率83.3%。结论:低场MRI可作为诊断椎管内神经鞘瘤的敏感检查方法,正确认识其MRI征象能帮助术前诊断,并指导手术。     

外周神经源性肿瘤的MRI表现与鉴别诊断

目的：探讨外周神经源性肿瘤的磁共振表现,旨在提高对该类疾病的影像学诊断水平。方法：回顾性分析经手术病理证实的外周神经源性肿瘤21例,其中神经纤维瘤14例,神经鞘瘤6例,恶性蝾螈瘤1例。所有神经源性肿瘤患者行 MRI 扫描。结果：4例神经纤维瘤表现为“葡萄藤”状,10例神经纤维瘤为分叶状,6例神经鞘瘤表现为梭形或类圆形肿块,恶性蝾螈瘤为团块状。神经纤维瘤 MR 均表现为 T1 WI 等信号,T2 WI 以高信号为主,其中夹杂低信号分隔;神经鞘瘤 T1 WI 呈稍低信号,T2 WI 表现为低信号周边环绕高信号即“靶征”;恶性蝾螈瘤在 T2 WI 上表现为高信号,其内可见环形或线样低信号分隔影。结论：外周神经源性肿瘤发生的部位、形状、大小以及信号特点均对其 MRI 诊断有帮助。     

髓内神经鞘瘤的MRI表现(附5例报告)

目的 探讨髓内神经鞘瘤的MRI表现,提高对该病的认识.资料与方法 回顾性分析经手术病理证实的5例髓内神经鞘瘤患者的临床和影像学资料.结果 4例肿瘤位于颈髓,1例位于胸髓.MRI 表现为类圆形或梭形的实性肿块,T1 WI呈等或稍低信号,T2WI呈等、稍高或稍低信号,肿瘤边界清楚,增强扫描肿瘤明显强化,且强化较均匀.结论 髓内神经鞘瘤常发生于颈髓,当颈髓内发生一边界清楚、增强扫描呈明显、较均匀强化的肿瘤时,应考虑到神经鞘瘤的可能,若同时可见明显的髓外部分或与肿瘤相连的神经根增厚,则应高度怀疑髓内神经鞘瘤.     

四肢软组织神经鞘瘤的MRI表现

目的 :探讨四肢软组织神经鞘瘤的MRI表现,旨在提高该病的影像学诊断水平。方法 :回顾性分析经手术病理证实的四肢软组织神经鞘瘤17例(18个病灶),均行MRI检查。结果:17例均表现为边界清楚的梭形、椭圆形肿块,沿神经走行方向生长;16例为单发,1例多发2个。12个病灶T1WI呈等信号,4个呈低信号,1个呈稍高信号为主夹杂斑点状更低信号,1个呈略高信号及散在低信号;T2WI表现各异。5个病灶可见靶征,14个可见偏心神经伴行,10个显示脂肪环绕。结论:四肢软组织神经鞘瘤的MRI表现有其特征性,有助于其正确诊断。     

椎管内神经源肿瘤的低场MRI诊断

目的 :评价低场MRI对椎管内神经源肿瘤的诊断价值。材料和方法 :回顾性分析 2 6例经手术病理证实的椎管内神经源肿瘤 (神经鞘瘤 16例 ,神经纤维瘤 10例 )的低场MRI表现。结果 :2 6例中肿瘤呈圆形或卵圆形 17例、长条形 1例、哑铃状 8例。神经鞘瘤 16例中T1WI呈等信号 4例 ,略低信号 4例 ,等、略低信号 8例 ,T2WI呈不均匀高信号 ;增强扫描均匀增强 2例 ,不均匀增强 14例 ,其中多灶样不增强 6例。神经纤维瘤 10例中T1WI呈等信号 6例 ,略低信号 4例 ,T2WI呈较均匀高信号 ;增强扫描均呈均匀增强。结论 :低场MRI检查能诊断椎管内神经源肿瘤 ,并能鉴别神经鞘瘤和神经纤维瘤     

脊柱区淋巴瘤的MRI特征

目的 分析脊柱区淋巴瘤的MRI表现,以提高对其的认识.方法 回顾性分析经手术及穿刺病理或临床随访证实的脊柱区淋巴瘤45例,其中原发性5例,均为非霍奇金淋巴瘤(NHL);继发性4|D例,其中霍奇金淋巴瘤(HL)9例,NHL 31例(B细胞型27例,T细胞型4例).将MRI表现与临床、病理结果进行对照.结果 (1)病变部位:单部位发病者13例,多部位发病者32例.5例原发性者均为单部位发病,继发性者40例中32例为多发.(2)病变类型:骨质破坏型27例,表现为不同程度的骨质破坏,23例合并有软组织肿块,18例软组织病变的范围超过骨质破坏的范围;软组织肿块型6例,骨质破坏不明显,5例表现为椎管内外软组织肿块并经椎间孔相连,呈围椎、钻孔生长的特点;骨髓浸润型9例,表现为椎骨髓质MRI信号异常,骨皮质完整,椎旁软组织正常;脊髓浸润型3例,表现为脊髓增粗和MRI信号异常.(3)MRI表现:椎骨骨质破坏和骨髓浸润表现为T1WI低信号,T2WI低、等或高信号,压脂T2WI高信号.软组织肿块与相邻正常肌肉相比,T1WI呈均匀低信号,T2WI呈高信号.增强扫描肿块多呈轻至中度强化,坏死液化不明显.结论 脊柱区淋巴瘤多为继发性B细胞NHL,其主要表现是溶骨性骨质破坏伴较大范围的软组织肿块,肿块有经椎间孔相连围椎、钻孔生长的特点,增强扫描呈轻至中度均匀强化.     

MR findings in eosinophilic infiltration of the liver

OBJECTIVE: This study describes the findings of magnetic resonance imaging (MRI) of focal eosinophilic infiltration of the liver. METHODS: Contrast-enhanced MR images of 8 patients with focal hepatic eosinophilic infiltration were reviewed retrospectively. We evaluated the signal intensity of focal lesions in T1-weighted and T2-weighted images and the pattern of enhancement in a dynamic contrast study. RESULTS: A total 22 focal hepatic lesions were observed; the lesions were isointense (55%) or hypointense (45%) on T1-weighted images and isointense (14%) or hyperintense (86%) on T2-weighted images. The arterial phase of the contrast study revealed 11 hyperintense lesions (50%). During the portal and delayed phases, 18 (82%) and 17 lesions (77%) were hyperintense, respectively. CONCLUSION: The focal eosinophilic infiltrations showed homogeneous enhancement in the portal and delayed phases in the dynamic contrast MR study. These findings should help to distinguish focal eosinophilic infiltration, especially from metastasis in patients with malignancy.     

臂丛区神经源性肿瘤的影像学诊断

目的：分析臂丛区神经源性肿瘤的影像学表现，探讨臂丛区影像检查方法。材料和方法：报告６例臂丛区神经源性肿瘤，其中神经鞘瘤４例，神经纤维瘤２例，均经手术及病理证实。结果：Ｘ线平片可见肺尖区肿块３例，椎间孔扩大１例。ＣＴ检查：示肿块平均直径约４ｃｍ，呈梭形４例，呈哑铃形２例；平扫密度与肌肉ＣＴ值相近，增强扫描肿块密度高于肌肉、低于血管。ＭＲＩ检查：示Ｔ１加权像上肿瘤信号与肌肉相近３例，略低于肌肉信号２例；Ｔ２加权像均为高信号，其中３例信号接近脑脊液（均为神经鞘瘤）。１例行增强扫描，病变呈中等度强化。结论：根据病变的分布及上述影像学表现，臂丛神经源性肿瘤可于手术前做出诊断；ＭＲＩ是显示臂丛区解剖及病变的优良方法     

Intradural schwannomas of the spine: MR findings with emphasis on contrast-enhancement characteristics.

Intradural extramedullary schwannomas are nerve sheath neoplasms that consist of focal proliferations of Schwann cells involving a spinal nerve. We reviewed the MR findings in seven patients with pathologically proved intradural schwannomas. The contrast-enhancement characteristics on MR images were determined and compared with the histologic features of the tumor. Six lesions were variably hyperintense on T2-weighted images and one was uniformly hypointense compared with the signal intensity of the spinal cord. Signal on T1-weighted images ranged from hypointense to isointense. All seven tumors showed heterogeneous enhancement; in five, the enhancement involved only the periphery of the lesion. The pattern of enhancement did not correlate with the signal characteristics noted on unenhanced T1- and T2-weighted images. Pathologically, hyaline thickening of vessel walls and cyst formation were prevalent in the peripherally enhancing lesions. However, enhancement did not correlate with the relative proportion of Antoni type A and type B tissue. Recognition of the MR characteristics of intradural extramedullary schwannomas may be helpful in the differential diagnosis of spinal tumors. In particular, peripheral contrast enhancement of an intradural extramedullary tumor on MR images should suggest the diagnosis of schwannoma.     

Focal nodular hyperplasia of the liver: MR findings in 35 proved cases

MR images of 28 patients with 35 lesions of hepatic focal nodular hyperplasia were reviewed to determine the frequency of findings considered typical of this condition (isointensity on T1- and T2-weighted pulse sequences, a central hyperintense scar on T2-weighted images, and homogeneous signal intensity). Fifteen lesions were imaged at 0.6 T with T1- and T2-weighted spin-echo (SE) pulse sequences; 20 lesions were imaged at 1.5 T with T1-weighted SE and gradient-echo pulse sequences and T2-weighted SE pulse sequences. Diagnosis of focal nodular hyperplasia was made pathologically in 25 patients, with nuclear scintigraphy in four, and with follow-up imaging in six. Only seven lesions (20%) were isointense relative to normal liver on both T1- and T2-weighted images. On T1-weighted SE images, 21 lesions (60%) were isointense relative to normal liver, 12 (34%) were hypointense, and two (6%) were hyperintense. On T2-weighted SE images, 12 lesions (34%) were isointense and 23 (66%) were hyperintense relative to normal liver. A central scar was present in 17 lesions (49%) and was hypointense relative to the lesion on T1-weighted images and hyperintense on T2-weighted images. Twenty lesions (57%) were of homogeneous signal intensity throughout the lesion, except for the presence of a central scar. All three MR imaging characteristics were present in three cases (9%). We conclude that hepatic focal nodular hyperplasia has a wide range of signal intensity on MR imaging.     

Infantile fibromatosis in childhood: findings on MR imaging and pathologic correlation

AIM: The objective of this study was to analyse the MR imaging findings of infantile fibromatosis of childhood and to correlate them with histopathological features. MATERIALS AND METHODS: Seven patients with histologically proven infantile fibromatosis were included in this study. The findings on MR images were retrospectively evaluated and then correlated with the pathological features. Findings on MR imaging evaluated included signal intensity, extent of hyperintense area on T2-weighted images, margins of the lesion, the degree and pattern of enhancement and the presence of fatty tissue. Pathological features evaluated included cellularity, collagenization, and myxoid change. A five point scale was used for the evaluation of the extent of hyperintense area on MR imaging, and each of pathological features. RESULTS: On T1-weighted images, the lesions were iso-intense in two patients; iso- and hypointense in three; and iso-, hypo- and hyperintense in two. On T2-weighted images, iso-, hypo- and hyperintense areas were mixed in all patients, the hyperintense area being the largest portion of the lesion. The margins of the lesions were infiltrative in four patients (57%), smooth in two (29%) and mixed in one (14%). Enhancement was marked in five patients (72%) and diffuse in five (71%). Regardless of the hyperintense signal intensity on T2-weighted images, the grades of each pathologic feature were variable. CONCLUSION: Infantile fibromatosis on MR imaging causes an enhancing mass, that is largely hyperintense on T2-weighted images. Areas of high signal intensity on T2-weighted images corresponded to variable grades of cellularity, collagenization, or myxoid change.     

Magnetic resonance imaging of the adrenal gland]

Adrenal imaging was performed using magnetic resonance (MR) was in 100 patients who had no clinical or biochemical evidence of adrenal abnormality and in 19 patients with 24 adrenal lesions (adenoma in 5, hyperplasia in 2, metastasis in 5, (lung cancer in 1, hepatoma in 4) adrenal cancer in 1, pheochromocytoma in 3, neuroblastoma in 3). Normal adrenal glands showed intermediate intensity between muscle and liver, and were detected in over 90% of cases on T1-weighted images (T1-weighted SE, inversion recovery). Adenomas and hyperplasias had the same intensity as normal glands. Medullary masses showed extreme hyperintensity on T2-weighted images and could be differentiated from cortical masses. Neuroblastomas were detected as hyperintense tumors with intratumoral hemorrhage and necrosis on T2-weighted MR images. Metastatic adrenal tumors from lung cancer were hyperintense on T2-weighted images, while metastasis from hepatoma showed low intensity on the same pulse sequence. In diagnosing adrenal metastasis, we must compare and contrast the tumor intensity and structure with those of the primary lesions. MR is considered a useful modality in characterizing adrenal tissue.     

Radiological findings of spinal schwannomas and meningiomas: focus on discrimination of two disease entities

This study evaluates the effectiveness of CT and MR imaging in differentiating intradural extramedullary spinal schwannomas and meningiomas in a large group of patients. In addition, the study correlates tumour location, morphologic characteristics and enhancement pattern. From January 2000 to June 2007, we retrospectively reviewed 128 consecutive patients (51 male, 77 female; mean age at admission 53.8 years; range 17–83 years) with spinal intradural extramedullary tumours (92 schwannomas, 36 meningiomas) at our institution. Fifty-one of ninety-two schwannomas (55.4%) showed fluid signal intensity on T2-weighted MR images. Twenty-two of thirty-six meningiomas (61.1%) showed hyperintense signal intensity and thirteen of thirty-six meningiomas (36.1%) showed isointense signal on T2-weighted MR images. Fifty-four schwannomas (58.7%) showed rim enhancement and thirty-three meningiomas (91.7%) showed diffuse enhancement on contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed dural tail sign in contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed calcification on CT images. MR and CT imaging results are therefore useful for the differentiation of schwannomas from meningiomas of the spine.     

Cross-sectional imaging of primary osseous hemangiopericytoma

The aim of this study was to assess cross-sectional imaging features and the value of CT and MRI in primary hemangiopericytoma of bone. In five patients with histologically proven primary osseous hemangiopericytoma CT and MR scans were evaluated retrospectively. Both CT and MRI were available in four patients each. In three patients both imaging techniques were available. On CT primary hemangiopericytoma of bone presents as an expansive lytic lesion with bone destruction and inhomogeneous contrast enhancement. Magnetic resonance imaging depicts osseous hemangiopericytoma as hyperintense lesion on T2-weighted images with intermediate signal intensity on T1-weighted images. Curvilinear tubular structures of signal void in the tumor matrix on T1-weighted images and corresponding hyperintense structures on T2-weighted and on fat-suppressed short tau inversion recovery images were present in three patients. Although cross-sectional imaging findings are non-specific, they add to the diagnosis and provide valuable information about the extent of bone destruction and local tumor spread in patients with primary osseous hemangiopericytoma. While CT demonstrates the extent of bone destruction best, MRI better visualizes medullary and soft tissue extension of the tumor. Curvilinear signal abnormalities support the diagnosis of hemangiopericytoma of bone. This imaging pattern is best visualized on fat-suppressed or contrast enhanced T1-weighted MR images.     

MRI of unusual lesions in the internal auditory canal

We report the MRI findings of six unusual lesions of the internal auditory canal: three haemangiomas, one lipoma, one metastasis and one traumatic neuroma. We compare the findings to those of 20 intracanalicular schwannomas. We noted the site and size of the tumour, its signal intensity, borders and the homogeneity of enhancement were studied on T1-weighted images before and after intravenous contrast medium and T2-weighted images. Most schwannomas were homogeneous lesions, isointense on T1- and T2-weighted images, and strongly enhancing. Spontaneous high signal on T1-weighted images, heterogeneous contrast enhancement and extranodular enhancement were helpful for recognising lesions other then schwannomas; site, size and signal on T2-weighted images were not. All the haemangiomas had a specific pattern of contrast enhancement, with an anterior core intensely enhancing portion and a posterior portion which enhanced moderately or not at all. Received: 4 November 1999/Accepted: 19 July 2000