Lipoma of the pancreas: MRI findings

Lipomas of the pancreas are very rare. Focal fatty infiltration of the pancreas is an entity that should be differentiated from a pancreatic lipoma. In this report the MRI findings of an incidentally found pancreatic lipoma are presented and the role of MRI in the differentiation of pancreatic lipoma and focal fatty infiltration of the pancreas is discussed.     

肝肺吸虫病的MRI表现

目的探讨肝肺吸虫病的MRI表现。方法对11例经临床或病理证实的肺吸虫病的肝脏MRI征象进行回顾性分析。结果单发病灶2例,多发病灶9例。病灶均分布在肝包膜下或门脉分支周围肝实质内,呈不规则形或条形,部分病灶在右肝后段可见“隧道征”;MRIT,wI呈等信号6例,呈稍高信号5例,TzwI呈稍高信号9例,稍低信号2例;动态增强扫描,多发病灶在动脉期及门脉期可见斑片状强化,延迟期病灶呈等信号,单发病灶可见周围环形强化,动脉期显示最清。结论肝肺吸虫病的MRI表现有一定特征,MRI对该病有较高的诊断价值。     

卵巢蒂扭转的MRI表现

目的：探讨M RI在诊断卵巢蒂扭转中的应用价值。方法回顾性分析13例经手术病理证实的卵巢蒂扭转患者的M RI表现特点,提高对本病的认识。结果本组13例中,原发性卵巢蒂扭转3例;继发性卵巢蒂扭转10例：卵巢单纯性囊肿5例,卵巢巧克力囊肿2例,卵巢浆液性囊性腺纤维瘤、卵巢卵泡膜纤维瘤及卵巢畸胎瘤各1例。M RI均表现为盆腹腔区异常信号肿块。肿块局部与一侧宫角及附件相连12例,另1例为2月婴儿,子宫显示不清。扭转的卵巢蒂呈典型结节征（或漩涡征）5例,悬挂征4例,三角征4例。合并盆腔积液6例,妊娠1例,子宫肌瘤1例,对侧卵巢巧克力囊肿1例。结论卵巢蒂扭转的M RI表现具有一定特征,是超声等检查的有益补充。     

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。     

肩关节周围浸润性脂肪瘤的磁共振诊断

目的探索浸润性脂肪瘤的磁共振特征。方法收集病理证实的肌肉内脂肪瘤患者8例,观察肿物磁共振图像的形状、大小、边界、信号特点。结果病变呈梭形,均位于横纹肌内,长径与肌纤维走形一致。8例肿物边界清晰或有包膜,3例内部信号不均匀。其余均呈短T1、长T2高信号影,脂肪抑制像上呈低信号影。结论浸润性脂肪瘤表现呈多样,多数为均匀一致高信号影,磁共振成像基于脂肪成像的特点,检查有助于此病的诊断。     

Interhemispheric lipoma with variable callosal dysgenesis: relationship between embryology, morphology, and symptomatology

Eight interhemispheric lipomas (five tubulonodular lipomas and three curvilinear lipomas) were examined by magnetic resonance imaging (MRI). The purpose was to further investigate the relationship between the morphology of the different subtypes and the clinical presentation. The imaging findings were reviewed in light of a recent theory on the development of the corpus callosum. Interhemispheric lipomas should be considered as one entity with a variable expression depending on the severity and/or the time of the insult. Curvilinear lipomas can be either small or extensive and are usually not symptomatic. Tubulonodular lipomas can be either predominantly anterior or posterior in location. The anterior subtype appears to be a more severe form of tubulonodular lipoma. The associated structural abnormalities are most likely responsible for the symptoms, rather than the lipoma itself. Magnetic resonance imaging allows a more precise timing of the insult, resulting in the development of a lipoma. The knowledge of the embryology between the 6th and the 20 h week is important to explain these abnormalities. Until now it has been accepted that the corpus callosum develops in an orderly fashion. A recent theory has demonstrated that this is not necessarily true, and that fibers can cross the midline at any place irrespective of the normal development. This theory explains the sometimes amorphous appearance of the remnant of the corpus callosum if a lipoma is present.Correspondence to: Ph. Demaerel     

不典型部位毛细胞型星形细胞瘤的MRI表现

目的：探讨不典型部位毛细胞型星形细胞瘤的MRI表现及特征,并与病理学对照,以提高对该病的诊断及鉴别诊断能力。方法：回顾性分析19例不典型部位毛细胞型星形细胞瘤患者的MRI表现及手术病理资料。结果：脊髓毛细胞型星形细胞瘤6例,大脑半球毛细胞型星形细胞瘤10例,侧脑室透明隔毛细胞型星形细胞瘤3例。19例中3例为实性伴微囊（发生在透明隔）,5例囊性（发生在脊髓及大脑半球）,11例囊实性改变（发生在大脑半球7例,脊髓4例）。1例发生间变,周围水肿明显,其余未见水肿。肿瘤实性部分在T1WI、T2WI信号接近脑皮质层或脊髓信号,囊性部分呈长T1WI、长T2WI信号改变,增强扫描实性部分呈明显强化,囊性部分未见强化。结论：MRI检查对不典型部位毛细胞型星形细胞瘤的定性诊断及其手术方案的制订具有重要价值。     

外伤性膝关节前外侧韧带损伤的MR影像特征及相关性分析

目的探讨外伤所致膝关节前外侧韧带损伤病人的MR影像特征,并分析其与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性,为深入研究前外侧韧带对膝关节稳定性的作用提供可靠依据。方法回顾性分析2016年1月—2017年2月间因外伤进行膝关节MRI检查的320例病人(共321膝)的影像资料。采用美国GE公司生产的Signa HDe 1.5 T MR扫描设备,分别行膝关节斜矢状面T1WI、质子密度加权成像(PDWI)和冠状面、横断面PDWI扫描。根据前外侧韧带的完整性和损伤部位对所有病人进行分类统计。采用独立性卡方检验对前外侧韧带撕裂与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性进行分析。结果全部病人膝关节MR影像均可显示前外侧韧带,显示率为100%。151/321膝(47.0%;95%CI为41.6%~52.5%)存在前外侧韧带损伤,其中累及胫骨部、股骨部及半月板部的分别为97膝、96膝及65膝。前交叉韧带撕裂158膝,外侧半月板撕裂98膝,股骨外侧髁挫伤58膝,外侧胫骨平台挫伤71膝,分别与前外侧韧带撕裂具有相关性(均P0.001)。结论 MRI检查可以很好地显示前外侧韧带解剖及其损伤情况。膝关节前外侧韧带损伤与前交叉韧带撕裂、外侧半月板撕裂及膝外侧骨挫伤具有相关性。     

膝关节侧副韧带及其损伤的MRI研究

目的 研究正常和损伤的膝关节侧副韧带的MRI表现。方法 对经手术或临床证实的32例共36条损伤的侧副韧带与56例正常膝关节进行回顾性MRI对比观察。结果 正常胫、腓侧副韧带在T1和T2WI上均呈扁平条状低信号结构,平均长度分别为6.8cm和5.7cm。36条侧副韧带损伤,单纯胫侧副韧带损伤18条,单纯腓侧副韧带损伤12条,两侧侧副韧带同时损伤3例6条。I级侧副韧带损伤18条;Ⅱ级侧副韧带损伤11条;Ⅲ级侧副韧带损伤7条。25例（78％）出现并发症,其中前交叉韧带损伤13条、后交叉韧带损伤9条、半月板损伤12个,骨挫伤和骨折7例,关节囊积液20例。结论 MRI能清楚显示膝关节侧副韧带结构,能准确诊断侧副韧带损伤并进行分级,还能发现多种并发症,宜列为膝关节外伤的常规检查。     

Lipoma arborescens of the glenohumeral joint causing bone erosion: MRI features with gadolinium enhancement

Lipoma arborescens is a rare benign intra-articular lesion that principally affects the knee joint. We present a case of lipoma arborescens involving the glenohumeral joint and associated with prominent large bony erosions. The gadolinium diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI) features of this lesion are also described. The characteristic MRI findings permit precise preoperative diagnosis of this rare condition even if it occurs in an atypical location and there are confusing radiological findings.     

Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function

The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) ‘classical’, homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2–15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon.     

膝关节树枝状脂肪瘤的MRI征象分析及其与骨性关节炎关系的探讨

目的 研究膝关节树枝状脂肪瘤(LA)的典型MRI表现以及伴随病变,并探讨其与骨性关节炎的关系.方法 回顾性分析13例LA患者的膝关节(n=15) MRI图像,其中2个膝关节为病理证实,其余13个膝关节有典型MRI表现诊断.所有患者均行MR平扫,其中1例行增强扫描.结果 全部病例均累及髌上囊,其中3例同时蔓延至关节周围滑膜,MR表现为滑膜呈“树叶”状、“树枝”状、“绒毛”状增厚,T1WI序列上为高信号、T2 WI序列上为稍高信号,脂肪抑制序列上呈低信号,1例增强后滑膜呈明显强化.其中局灶结节型6.7％ (1/15),弥漫型53.3％ (8/15),混合型40.0％ (6/15).15个受累膝关节均伴关节积液;其中93.3％(14/15)伴骨性关节炎改变;40.0％ (6/15)伴半月板损伤;26.7％ (4/15)伴滑膜囊肿;20.0％(3/15)伴关节旁滑膜增厚;6.7％ (1/15)伴滑膜骨软骨瘤病.结论 膝关节LA在MRI上有特征性的形态信号改变,LA是引起骨性关节炎的因素之一.     

急性脑梗塞早期MRI表现与病理对照研究

目的阻断狗大脑中动脉建立急性脑梗塞动物模型,观察早期MRI表现及其病理改变。材料与方法将16只成年狗随机分为实验组(10只)和对照组(6只)。经颞开颅阻断一侧大脑中动脉(MCA),造成其供应区急性缺血性脑梗塞,只成年狗随机分为实验组(10只)和对照组(6只)。经颞开颅阻断一侧大脑中动脉(MCA),造成其供应区急性缺血性脑梗塞,术后2,4,6,8,12小时行MRI薄层扫描;取出动物大脑观察病理改变,测定不同时相梗塞区T2时间和组织水含量。结果MRI最早2小时表现异常,T2加权像可见尾状核头部、豆状核信号增高;梗塞6小时,MRI可见尾状核、豆状核形成明确梗塞,并出现占位征象。梗塞2小时,电镜下已有缺血水肿改变,4小时光镜下出现脑缺血水肿改变,电镜下见血脑屏障受损。相关分析表明病灶区T2时间变化与组织水含量变化在时序上有密切关系,经t检验差别具显著意义(P＜0．01)。结论本项实验结果表明,MRI可用于脑梗塞早期的诊断,在显示病灶方面,MRIT2加权像优于T1加权像。急性脑梗塞早期MRI表现的病理基础是脑水肿。     

脊柱原发性骨质疏松椎体压缩的MRI表现

目的探讨脊柱原发性骨质疏松椎体压缩的ＭＲＩ表现。方法对３年间Ｘ线诊断、临床证实的６０例脊柱原发性骨质疏松的ＭＲＩ表现进行回顾分析，并与对照组比较。结果１６２个椎体表现为压缩变形，其中凹陷形９８个，楔形５１个，扁平形１３个。压缩椎体邻近椎间盘常膨突到椎体凹陷区内；矢状位Ｔ１ＷＩ４７个椎体表现为椎体内不同范围、不同类型的低信号。结论压缩椎体后上角突入椎管内，Ｔ１ＷＩ椎体终板下呈带状低信号和除椎体后角外全椎体呈低信号，为原发性骨质疏松椎体压缩ＭＲＩ比较典型的表现。     

椎管内硬膜外血管脂肪瘤的MRI表现

目的探讨MRI对椎管内硬膜外血管脂肪瘤的诊断价值。方法回顾性分析经手术病理证实的7例椎管内硬膜外血管脂肪瘤的MRI表现，并进行MR分型。结果7例均位于胸段椎管，其中上胸段2例，中胸段2例，下胸段3例。肿块位于硬膜外，呈梭形，长轴与脊柱纵轴平行，肿瘤的MR信号由脂肪和血管2部分构成，血管成分在T1WI呈低信号，T2WI为高信号，可明显强化，未见血管流空影。全部病例依MRI表现分3型：Ⅰ型2例，特点是血管成分稀少，呈细条状、斑点状夹杂于脂肪组织间；Ⅱ型3例，特点是血管成分呈团块状，占据瘤体的中央；Ⅲ型2例，肿瘤沿一侧或双侧椎间孔向椎管外生长，形成哑铃状外观。结论MRI是诊断此病的最佳方法，并具有相对特征性表现。MRI分型对该病的诊断和鉴别诊断有一定实用价值。     

MRI appearances mimicking the dural tail sign: a report of two cases

We report two cases in which the MRI appearances mimicked the dural tail sign; a glioma extending into the subarachnoid space, and a meningioma extending to the subdural space. They indicate that tumour invasion into the subarachnoid or subdural space, should be considered when prominent linear enhancement is observed along the dura mater adjacent to tumours. Received: 31 March 1999/Accepted: 21 July 1999     

Replacement lipomatosis related to renal tuberculosis: imaging findings in one case

Replacement lipomatosis of the kidney in a case of long-standing renal tuberculosis is reported. The radiologic and pathologic findings are described and the differential diagnosis is discussed. A hypothesis is given to explain the association of renal tuberculosis and replacement lipomatosis of the kidney.     

Unusual MRI appearances of cysticercus within the fourth ventricle

We report a cysticercus within the fourten ventricle which showed unusual hypointensity on T2-weighted images.     

儿童线粒体脑肌病的脑部MRI表现与诊断

目的探讨儿童线粒体脑肌病的脑部MRI表现及其诊断价值。方法搜集1996年1月至2002年12月经病理与实验室检查证实的16例儿童线粒体脑肌病及其脑部MRI表现，并进行回顾性分析。结果16例患儿脑MRI均有多发对称性片状略长T1和长T2异常信号，其中单纯脑深部灰质受累9例，大脑皮质和深部灰质同时受累6例，单纯白质受累l例。临床主要表现为进行性智力减退(12例)和肌力减退(10例)。骨骼肌活检病理检查可见破碎样红纤维及异常线粒体。结论进行性智力和肌力减退是儿童线粒体脑肌病最常见的临床表现；脑深部灰质多发对称性斑片状异常信号是儿童线粒体脑肌病脑部MRI的主要表现；脑MRI是诊断儿童线粒体脑肌病的重要手段，但儿童线粒体脑肌病的确诊有赖于肌肉活检和基因检查。