Dynamic MRI of meningiomas and schwannomas: is differential diagnosis possible?

We studied 23 patients with meningiomas and 14 with schwannomas using dynamic spin-echo (TR/TE 200/15 ms) MRI. Histologically the meningiomas were classified according to the 1993 WHO classification. Serial images were obtained every 30 s for 210 s after rapid injection of gadopentetate dimeglumine (0.1 mmol/kg). The contrast-enhancement ratio (CER) was divided into three patterns; a sharp rise with a peak within 60 s (A), a relatively rapid increase with a peak between 60 and 210 s (B), a slow increase without a peak (C). The patterns were correlated with the histology of the tumors. The signal intensities of the tumours on T2-weighted images were also analyzed and correlated with the dynamic patterns. Meningiomas had more varied dynamic patterns than schwannomas. Almost half of the meningiomas showed pattern A, and one third pattern C. Of six meningothelial meningiomas showed pattern A; all schwannomas and fibrous meningiomas showed pattern C. Various patterns were observed in transitional meningiomas. Of the 8 meningiomas showing pattern C, only one gave high signal on T2-weighted images, and could not be differentiated from the schwannomas. Thus, one third of meningiomas could not be differentiated from schwannomas by the dynamic contrast enhancement alone. However, when this was combined with the signal intensity on T2-weighted images, most meningiomas could be differentiated from schwannomas. Received: 17 June 1996 Accepted: 11 October 1996     

眼眶静脉曲张MRI表现

 目的探讨眼眶静脉曲张的MRI影像学特征.方法 6例选自我院患者,行仰卧位及俯卧位MRI检查.结果6例受检者中,左眼5例,右眼1例,3例显示为眼眶内外条索状等T1长T2信号影,2例显示为眼眶尖结节状等T1长T2信号影,1例位于眶后弥漫性分布软组织长T1长T2信号影,强化方式多种多样,有斑点状、环状、结节状强化.结论影像学特征对临床治疗方案的制定很有价值.     

MRI of intramedullary spinal schwannomas: case report and review of the literature

Intramedullary spinal schwannomas are uncommon. We report a solitary cervical intramedullary schwannoma shown by MRI and treated surgically, and review 12 previous cases with MRI. MRI findings and pathogenesis are discussed. Received: 22 March 1999 Accepted: 2 August 1999     

动态增强MRI对眼眶病变诊断及鉴别诊断的价值

目的运用动态增强MR技术，分析病变的强化特点，以提高对不同眼眶病变的认识，尤其是不同良性肿瘤及恶性肿瘤的强化特点，进而提高MRI的诊断价值。方法共41例，均为单发病灶，均行MR检查，术后均得到病理证实。其中良性肿瘤和类肿瘤病变3l例，恶性肿瘤病变10例。使用1．5T超导MR机，头颅线圈采集。MR平扫包括：横断面T1WI、T2WI及T1WI矢状和冠状面扫描。层厚4mm。增强检查为使用对比剂后立即连续动态扫描，以观察病变的动态变化状况。对所测得的平扫及动态增强信号强度值（前、后），计算其强化率（E％）并得到时间-密度曲线（TIC），并进行统计学分析。结果（1）良恶性肿瘤第1分钟内平均强化率（E1％）比较：恶性肿瘤的E1％〉60％，而良性肿瘤的E1％〈60％，二者差异有统计学意义（P〈0．05）；（2）27例良性肿瘤除脑膜瘤外，绝大多数（88．9％，24例）强化为线型；（3）10例恶性肿瘤和3例脑膜瘤为平台型强化。（4）3例炎性假瘤和1例肉芽肿病变，表现为流出型。（5）12例海绵状血管瘤有特殊的强化模式，表现为局部点状和小结节状强化，然后逐步向全肿瘤扩展。结论动态增强MR检查，对鉴别良恶性肿瘤有明显意义；对鉴别肿瘤和炎症也可提供重要的诊断依据；少数病种，如海绵状血管瘤有特殊的强化模式。     

眼眶原发性淋巴瘤的MRI表现

目的：探讨眼眶原发性淋巴瘤的磁共振影像学表现,以提高其诊断的准确率。方法对11例经手术病理证实的原发性淋巴瘤的临床和影像学资料进行回顾性分析。结果眼眶原发性淋巴瘤的MRI特征如下：①好发于隔前眶周,以眼眶外上象限为主,包括眼睑、泪腺、结膜等;②无包膜,沿眼眶间隙蔓延塑形生长;③平扫T1WI呈等信号,T2WI呈稍高信号,增强呈中-重度强化;④DWI上表现为高信号;⑤边界较清晰,对周围组织结构侵犯、破坏少见;⑥囊变少见,出血、钙化罕见。结论眼眶原发性淋巴瘤MRI表现具有一定的特征性,MRI多方位成像可对肿瘤明确定位,并有助于定性诊断。     

常见眼眶病变的MRI诊断与鉴别诊断

目的：探讨眼眶病变的MRI诊断与鉴别诊断价值。方法：对29例经临床病理确诊的眼眶病变的病例进行回顾性分析，重点观察该类疾病的MRI表现。结果：眼眶病变29例，包括肿瘤10例。炎症10例，血管性病变3例，眼肌病变6例。其在MRI表现各具有影像学特征，眼眶肿瘤多表现为位于眼眶内、外的局限性软组织肿块，MR T1WI呈等或稍低信号，T2WI呈高或等信号多见；炎性假瘤则表现为眶内局限性软组织肿块或弥漫性异常信号．MR T1WI呈低信号，T2WI呈高信号，常伴有眼肌肥大或眼环增厚，泪腺肿大等。结论：MRI检查能显示眼眶病变的影像学特征，对其诊断及鉴别诊断具有重要价值。     

眼眶神经鞘瘤的CT和MRI研究

目的 研究眼眶神经鞘瘤的ＣＴ和ＭＲＩ表现,提高其诊断准确率。方法 １９例手术病理证实的眼眶神经鞘瘤,其中１５例行ＣＴ扫描,１０例行ＭＲ扫描,对照手术病理结果,比较分析ＣＴ和ＭＲＩ的诊断准确率。结果 ８例位于肌锥内,８例位于肌锥外,３例位于眼眶和海绵窦,为颅眶沟通性神经鞘瘤;１５例呈椭圆形,４例呈哑铃形。１１例神经鞘瘤ＣＴ平扫呈等密度,密度均匀,９例行增强扫描均呈均匀强化;３例呈等密度,密度不均匀,     

眼眶脑膜瘤的MRI诊断研究

目的：探讨眼眶脑膜瘤的发生部位、MRI的信号特征及鉴别诊断。方法：搜集经手术病理证实的眼眶脑膜瘤43例，行MRI扫描及增强脂肪抑制扫描，分析其发生部位与信号特征。结果：依据眼眶脑膜瘤的发生部位分为下列4种：①视神经鞘脑膜瘤，肿瘤呈不规则管状软组织增生，环绕视神经生长，等信号、T2WI及增强脂肪抑制成像显示肿瘤与视神经界限清楚。②眶壁(内)脑膜瘤，肿瘤呈宽基底等信号软组织块与眼眶壁紧贴，突向眶内，或位于肌锥内，边界清楚，增强明显。③蝶骨嵴脑膜瘤，肿瘤沿蝶骨嵴内外侧生长，向内侵犯眶内组织，向外累及翼腭窝。④眶颅沟脑膜瘤，肿瘤通过眶上裂、视神经管或骨质破坏缺损区呈哑铃形向眶内及颅内生长，等信号，增强显著。结论：应用合适的MRI扫描技术，可清晰准确地显示眼眶脑膜瘤的范围、部位、形态及信号特征，为临床手术治疗提供明确的定位、定性信息和诊断依据。     

MRI对眼部淋巴瘤的诊断价值

目的分析眼部淋巴瘤的MRI表现,探讨MRI对该病的诊断价值。资料与方法对58例经手术病理证实的眼部淋巴瘤患者的MRI资料进行回顾性分析。结果 58例中,27例病变呈弥漫性分布,其中7例位于肌锥内,9例位于肌锥外,11例同时累及肌锥内外间隙;31例病变较局限,主要累及泪腺区24例,结膜3例,眼外肌2例,泪囊区1例,眼睑1例。31例局限性病灶边缘清晰,其中13例呈铸型生长;27例弥漫性病灶形态不规则,边缘模糊,与邻近结构分界不清。T1WI上46例呈中等或中等偏低信号,12例呈低信号;T2WI上39例呈中等信号,12例呈低信号,7例呈高信号;增强扫描后病灶均匀强化。结论眼部淋巴瘤在MRI上具有一定的信号特点,且MRI可清楚地显示病变范围及其与邻近结构的关系,对于该病的诊断具有重要意义。     

Schwannoma of the tip of the nose: MRI

We report a schwannoma with a rare location at the tip of the nose in a 20-year-old woman with an otherwise unremarkable medical history. The imaging findings unterline the usefulness of MRI in narrowing down the differential diagnosis of masses in this region. Once the diagnosis was focussed on a neural origin of the mass, the exact nature of the tumour could not be predicted from the MRI, although the presence of a capsule on imaging studies as well as at operation suggested it was probably a schwannoma. A schwannoma must be considered when one encounters a sharply delineated mass at the tip of the nose, showing high signal on T2-weighted images and strongly contrast enhancement. Received: 17 July 1997 Accepted: 2 October 1997     

儿童眼眶转移性神经母细胞瘤和绿色瘤的特征性MR表现

目的 分析儿童眼眶转移性神经母细胞瘤和绿色瘤的特征性MR表现。资料与方法 回顾性分析经手术病理证实的9例儿童眼眶转移性神经母细胞瘤和5例绿色瘤的CT和MRI表现。所有病例均行CT平扫以及MRI平扫和增强扫描。结果 14例CT表现均为眼眶不规则肿块和邻近的眶壁溶骨性骨质破坏,7例骨质破坏区邻近的颅内可见扁平不规则肿块。2例转移性神经母细胞瘤表现为眼眶肌锥外间隙肿块内有与眶外壁垂直的针状高密度影。14例MRI表现为眼眶肌锥外间隙略长T1、略长T2信号不规则软组织影,7例骨质破坏区邻近的颅内硬膜外间隙可见略长T1、略长T2信号扁平不规则肿块,增强后明显强化。14例双侧眶骨及蝶骨大翼,9例斜坡和双侧岩尖及2例双侧颞骨鳞部骨髓腔脂肪高信号影被略长T1、略长T2信号影取代,采用脂肪抑制的增强T1WI显示均有强化,强化程度与眼眶内肿块相似。结论 儿童眼眶转移性神经母细胞瘤和绿色瘤的眶壁和颅面骨MR表现具有特征,有助于诊断和鉴别诊断。     

臂丛神经鞘瘤的MRI表现与手术对照研究

目的:评价臂丛神经鞘瘤的MRI表现,并与手术所见对照分析,以期对临床诊治有所裨益。材料和方法:经手术和病理证实的36例臂丛神经鞘瘤,术前均行MRI检查。所有患者MRI检查序列包括轴位T2WI(STIR),增强前后横断面、斜矢状面和冠状面T1WI(增强后扫描加脂肪抑制),部分病例增强前加扫冠状面T2WI。2名有经验的放射科医师分别对病变部位、肿块大小、边界、信号、强化及范围作出判断。病变的定位及MRI不同序列中的特征与手术和病理表现行对照研究。结果:臂丛神经的根、干及分支在MRI所有序列中均表现为线状低信号影。36例臂丛神经鞘瘤平均大小为4.9cm(3.0～6.8cm),均表现为沿臂丛神经根生长的肿块。30例表现为边界清楚的纺锤形或长圆形肿块。MRI信号特点:16例表现为均匀的T1WI低或等信号(与肌肉相比),T2WI高信号,增强后中等度强化;20例T1WI呈低信号,T2WI呈不均匀高信号,内见低信号区,所谓的“靶征”,增强后明显强化。所有患者的显微外科手术均遵循肿块内容物的摘除,包膜的剥离与神经的保护相结合的原则。结论:根据臂丛神经鞘瘤的特征性部位和形态学表现以及MRI信号特点,能对本病作出诊断、鉴别诊断及预后判断。该病的典型表现有利于术前作出正确诊断,显微外科手术有利于保护有关神经。     

MRI of orbital hydroxyapatite implants

Our aim was to use MRI for the postsurgical assessment of a new form of integrated orbital implant composed of a porous calcium phosphate hydroxyapatite substrate. We studied ten patients 24–74 years of age who underwent enucleation and implantation of a hydroxyapatite ball; 5–13 months after surgery, each patient was examined by spinecho MRI, with fat suppression and gadolinium enhancement. Fibrovascular ingrowth was demonstrated in all ten patients as areas of enhancement at the periphery of the hydroxyapatite sphere that extended to the center to a variable degree. The radiologist should aware of the MRI appearances of the coralline hydroxyapatite orbital implant since it is now widely used following enucleation. MRI is a useful means to determine successful incorporation of the substrate into the orbital tissues. The normal pattern of contrast enhancement should not be mistaken for recurrent tumor or infection.     

MR扩散加权成像在眼眶良恶性肿块鉴别诊断中的应用

目的 分析眶内良恶性肿块的扩散加权成像(DWI)特征,评价表观扩散系数(ADC)值对其诊断价值.方法 对77例眶内肿块进行常规MRI及DWI,其中良性肿块55例,恶性肿块22例.扩散敏感系数(b)值=0、1000 s/mm2,测量病变对侧颞叶脑白质感兴趣区DWI信号,获得相应的肿块区ADC(ADCM)值、病变对侧颞叶脑白质ADC(ADCw)值,计算二者比值(ADCR).以不同ADCM值及ADCR作为临界点区分眶内良恶性肿块绘制出受试者工作特征曲线(ROC).结果 眶内良性肿块ADCM值及ADCR分别为(1.56±0.75)×10-3mm2/s、1.85±0.91;恶性肿块ADCM值及ADCR分别为(1.09±0.42)×10-3mm2/s、1.28±0.53;良性肿块ADCM值及ADCR显著高于恶性肿块(t值分别为2.803、2.735,P值均＜0.01).以不同ADCM值、ADCR作为临界点判断眶内良恶性肿块绘制ROC,曲线下面积均为0.71±0.07.以ADCM值为1.05×10-3mm2/s作为判断眶内良恶性肿块的决定值,灵敏度、特异度和准确率分别为59.1%(13/22)、78.2%(43/55)和72.7%(56/77);以ADCR为1.24作为决定值,灵敏度、特异度和准确率分别为59.1%(13/22)、76.4%(42/55)和71.4%(55/77).结论 DWI可揭示眼眶肿块的扩散特征,ADC值对于良恶性肿块的鉴别诊断具有辅助诊断价值.     

眼眶孤立性纤维瘤的MRI表现

目的：探讨MRI诊断眼眶孤立性纤维瘤的价值。方法：回顾性分析5例经病理证实的孤立性纤维瘤,5例均作眼眶MRI扫描,对其MRI表现进行研究分析。结果：5例眼眶孤立性纤维瘤为单发、边界清楚肿块,大小1.6-3.8 cm。发生于泪腺1例,肌锥内间隙2例,肌锥外间隙2例。平扫T1WI肿瘤呈等、稍低信号,T2WI信号不均匀,2例呈等、稍低信号,2例呈等、稍高信号,1例呈高信号。增强扫描4例呈明显较均匀强化,1例呈轻度至中度强化。结论：眼眶孤立性纤维瘤MRI表现具有一定特征性,明确诊断需结合免疫组织化学分析。     

CT、MRI在眼眶炎性假瘤的诊断价值

目的:探讨CT和MRI对眼眶炎性假瘤的诊断和鉴别诊断价值。方法:回顾性分析经临床、病理证实的63例眼眶炎性假瘤的影像学表现。结果:根据病变累及部位及形态学表现分为:①隔前型2例,表现为眼睑肿胀;②巩膜周围炎型1例,表现为眼球壁增厚;③视神经束膜炎型3例,表现为视神经增粗;④弥漫型10例,病变可同时累及眶隔前组织、眼肌、视神经、眼环、泪腺、眶内脂肪或眶周组织;⑤肿块型12例,表现为边界清楚的肿块;⑥泪腺炎型9例,表现为泪腺肿大;⑦肌炎型26例,表现为1条或数条眼外肌增粗、肥大。结论:CT和MRI能对眼眶炎性假瘤确切定位及分型,为临床治疗方案提供重要依据,二者的结合极大地提高了眼眶炎性假瘤的正确诊断率。     

MRI脂肪抑制和增强技术在诊断眼眶疾病中的应用

目的 研究磁共振脂肪抑制技术和钆喷替酸菊甲胺（Ｇｄ－ＤＴＰＡ）增强造影在眼眶病变中的应用及其价值。方法 对８５例眼球和眶内病变分别行平扫、使用脂肪抑制技术和（或）Ｇｄ－ＤＴＰＡ增强扫描,并比较分析使用脂肪抑制技术前后以及增强扫描对病变的显示情况。结果 ８５例眼球和眶内病变的边缘、轮廓和范围及其周围正常结构的关系在使用脂肪抑制技术后的扫描序列上较在未使用该技术的序列上显示得准确清楚。７例视神经不增粗     

眼眶炎性假瘤眶外蔓延的MRI表现

目的探讨眼眶炎性假瘤眶外蔓延的途径、MRI表现与临床特点。资料与方法回顾分析我院2005年11月至2010年12月收治的13例经手术或临床证实的炎性假瘤眶外蔓延的病例,结合文献总结其临床特点与MRI表现结果13例患者中慢性病程9例,急性或亚急性病程4例。5例手术证实,其中3例为混合型炎性假瘤,2例为硬化型炎性假瘤。8例临床证实,经激素冲击治疗,症状明显缓解。MRI表现为经眶上裂蔓延13例,经眶下裂蔓延10例,经视神经管蔓延1例,经眶下孔蔓延3例。眶外蔓延者临床表现与无眶外蔓延者比较无特异性。结论炎性假瘤眶外蔓延主要经眶上裂、眶下裂蔓延,常在影像检查中被发现。MRI能清楚显示眶外蔓延的途径及范围。     

眼眶骨膜下间隙血肿的CT、MRI表现

目的分析眼眶骨膜下间隙血肿的CT、MRI表现并探讨其临床价值。资料与方法36例（36眼）眼眶外伤性骨膜下血肿患者中,同时行眼眶CT、MRI检查2例。仅行眼眶CT检查30例．横断位、冠状位检查25例,横断位1例,冠状位检查4例。仅行MRI检查4例。结果跟眶CT显示骨膜下间隙血肿32例,其中上壁18例,外上壁7例,外壁5例,下壁2例。病变广基附于眶壁,内缘清楚,密度均匀,一般不跨越骨缝。眼眶MRI显示上壁骨膜下间隙血肿6例,信号取决于出血时间。结论眼眶骨膜下间隙血肿多发生于眼眶上壁。CT、MRI有助于对该病的诊断及鉴别诊断。     

Neurosarcoma of the face: MRI

Neurosarcoma is a rare tumour originating from the sheath of peripheral nerves. Facial lesions have been reported in about 20 patients. We describe the MRI appearances of neurosarcoma with histological correlation in three patients. The lesions lay in the submandibular region, the left parapharyngeal space and the right orbit. MRI showed a well-defined mass with mixed components. The lesions were moderately heterogeneous on T1-weighted images in two cases and on T2-weighted images in all cases. Gadolinium enhancement occurred in all cases to variable degrees. In two cases, small high signal foci were seen on T2-weighted sequences. MRI appearances of neurosarcoma are not specific. Received: 3 September 1996 Accepted: 26 November 1996