囊性脑转移瘤的CT和MRI诊断

目的探讨囊性脑转移瘤的CT、MR I表现特点。方法经临床或病理证实的囊性脑转移瘤26例,男13例,女13例,平均年龄52.7岁。15例行CT平扫,13例行MR平扫,11例行增强CT和/或增强MR I扫描。结果26例共48个囊性脑转移灶,囊壁CT平扫呈等或稍高密度,MR T1W I和T2W I呈等或稍低信号,根据囊壁的形态将其分为3种类型:不均型、结节型、均匀型。MR T1W I囊液信号强度略高于、T2W I高于脑脊液信号强度,而CT密度与之相似或略高。增强扫描肿瘤呈环形强化,部分病灶可见强化壁结节。结论囊性脑转移瘤形态多样,需与脑脓肿及其他肿瘤性囊性病变相鉴别,MR I多方位增强扫描对诊断很有帮助。     

低场MR增强扫描对脑转移瘤的诊断价值

目的：探讨低场MR增强扫描对脑转移瘤的诊断价值.方法：回顾分析70例脑部转移瘤病人用0.5T超导型磁共振扫描仪做的平扫和Gd-DTF＇A增强扫描的MRI征象.结果：70例脑转移瘤病人,平扫检出118个转移灶,Gd-DTP＇A增强扫描检出239个转移灶.平扫检出最小病灶直径0.9 cm,增强扫描栓出最小病灶直径0.2 cm.结论：低场磁共振Gd-DTPA增强扫描既能发现平扫难以发现的脑转移瘤,又可以准确发现微小和特殊部位的转移灶,同时又可以明确病灶形态、边缘以及内部情况.为临床治疗方案的确定提供可靠依据.     

肝脏囊性转移瘤的CT和MR征象的比较

目的:分析肝脏囊性转移瘤在CT和MR上的表现,比较CT和MR检查对囊性转移瘤的临床诊断价值.材料和方法:18例(共52个病灶)肝脏囊性转移瘤中10例行CT平扫和增强门脉期扫描.8例行MR T1WI和FMP-SPGR多期动态增强扫描.观察肿瘤的大小、形态、数目、囊壁和壁结节的强化情况.结果:2例为单发病灶外,其余均为多发病灶.病灶呈类圆形或椭圆形.CT上8例见到囊壁不规则增厚,其中6例可见向囊腔内突起的壁结节,1例内有分隔.2例薄壁且均匀的病灶误诊为肝囊肿.T1WI上,7例为低信号,1例为混杂信号.T2WI上,病灶均为明显高信号,2例信号均匀,6例信号不均匀,可见到壁结节为略低信号.增强动脉期所有病灶均无强化表现,门脉期和延迟期,可见到边缘环形强化和壁结节的强化.也有1例见到分隔.结论:CT和MR均可显示肝脏囊性转移瘤的特征,MR在显示病灶的出血、囊变、分隔和囊壁的情况等比CT更为敏感、可靠,在鉴别诊断方面价值更大.     

婴儿型肝脏血管内皮瘤的影像诊断

目的 总结婴儿型肝脏血管内皮细胞瘤的临床与影像学表现. 资料与方法 回顾性分析6例婴儿型肝脏血管内皮细胞瘤的临床与影像学表现,所有的病例均经穿刺病理证实.5例行CT扫描,1例行MRI平扫. 结果 CT平扫表现为肝内低密度灶,1例出现钙化,增强扫描动脉期肿瘤均呈不均匀环形强化,4例中央部位出现结节样强化;门静脉期全部病例由周边向中心强化,强化范围扩大;延迟期病灶密度稍高于或等于正常肝实质.1例MR表现为肝内多发结节,T1WI低信号,T2WI高信号,增强扫描动脉期部分结节呈环形强化,部分结节呈全瘤均匀强化,延迟期全部结节呈全瘤强化. 结论 本病的CT与MRI表现有一定的特征性,有助于诊断本病.     

脑型肺吸虫病的CT和MRI诊断

目的探讨脑型肺吸虫病的CT和MRI表现,旨在提高其诊断准确性。方法回顾性分析经手术后病理证实或诊断性用药后疗效显著的15例脑型肺吸虫病的影像表现特点。结果5例行CT平扫,主要表现为多发或单发不规则低密度水肿区及出血灶;其中3例行CT增强扫描,增强后呈结节状、环状强化明显,2例见"隧道"征。12例行MRI平扫,其中10例有多发、不规则、大小不等的出血灶,部分病灶较小,围绕与出血灶不相称的较大的水肿信号;病灶随机分布,并呈聚集或迁移状,3例可见"隧道"征,增强扫描见斑片状、结节状、单发或多发小环状强化,"隧道"征更加明显。结论MRI对脑型肺吸虫病的临床诊断具有重要价值,但脑型肺吸虫病的明确诊断还应结合流行病史、临床表现、实验室检查等。     

钙化上皮瘤的影像表现及病理基础

【摘要】目的：分析钙化上皮瘤的CT及MRI表现,并探讨其病理基础。方法：回顾性分析17例经手术病理证实的钙化上皮瘤患者影像学资料并复习相关文献,其中8例行CT平扫及增强扫描,6例行MR平扫及增强检查,2例仅行CT平扫,1例先行X线片,后行MR平扫加增强检查。结果：10例CT共13个病灶。8个病灶见钙化,其中5个病灶完全钙化。2个病灶见坏死。10个病灶边界清清楚,3个瘤周见絮状稍高密度影。8例CT增强扫描共11个病灶,其中3个轻度强化,5个不均匀中度强化,3个病灶完全钙化无强化。6例MR均为单发,2例T1WI呈等信号,T2WI呈外周高中央低信号,DWI呈环状高信号,增强呈“环靶征”。2例T1WI呈等或稍高信号,T2WI呈高信号,内见微囊状更高信号,灶周可见斑片状高信号,增强不均匀强化。2例T1WI呈稍低信号,T2WI均呈稍高信号,增强不均匀强化。1例X线片呈高密度,T1WI呈低信号,T1WI压脂呈不均匀稍高信号,T2WI压脂呈高低混杂信号,增强扫描不均匀强化,以中央强化较为明显。结论：钙化上皮瘤的影像表现有一定特征,当病灶位于皮下,边界清楚,CT见广泛泥沙样或致密的局灶性钙化,MR上见微囊状改变,增强扫描轻至中度强化,尤其呈“环靶征”表现时,应考虑到PM的诊断。     

软组织转移瘤影像学诊断

目的探讨软组织转移瘤的影像学表现特点。方法选择经病理证实的软组织转移瘤35例,分析其CT和MRI表现特点。结果 CT检查31例,其中平扫13例,增强扫描15例,平扫并增强扫描3例。MRI平扫3例。19个肌肉内转移瘤CT平扫表现为等密度或略低密度肿块,边界不清,密度均匀或不均匀,最大径1.2~25.3cm;4例(21.52%)表现为弥漫性肌肉肿胀,密度均匀,与炎症相似;3例肿块内可见成簇的颗粒状或无定形钙化。9个皮下组织转移瘤CT平扫表现为多发或单发结节状或团块状等或略低密度灶,最大径0.5~5.2cm,边界清;2个表现为皮下组织内饼状软组织密度灶,边界不规则。CT增强扫描,病灶呈均匀或不均匀轻中度强化;其中7例(33.33%)呈环形强化,病灶中心不强化。3例MRI平扫表现为等长T1,不均匀长T2异常信号;2例边界清楚,1例边界不清。结论软组织转移瘤不罕见,在软组织肿瘤诊断中应注意鉴别。     

脑实质内单发转移瘤的高场强MR诊断和鉴别诊断

目的：探讨脑实质内单发转移瘤的MR诊断与鉴别诊断，方法：17例脑实质内单发转移瘤均经1．5T高场强度共振扫描仪检查，采用T1加权，T2加权和质子密度加权扫描序列进行扫描，扫描方法包括轴位，矢状位和冠状位，其中15例平扫后再行Gt-DTPA增强扫描。结果：病灶位于大脑半球10例，小脑为7例，12例病灶位于皮髓质交界区偏皮质内，并有6例病灶已达脑实质表面，病灶多数呈圆形或类圆形，不无效长T1和长T2信号，发生坏死囊变11例，出血6例。病灶均表面有不同程度的占位效应和瘤周水肿，增强后呈不均匀性明显强化。结论：通过MR检查注意观察脑实实内单发转移瘤的部位，形态，大小，信号及增强等变化可对其进行正确的诊断和鉴别诊断。     

囊性脑转移瘤的CT和MRI表现

目的：探讨CT和MRI诊断囊性脑转移瘤的价值。材料和方法：回顾性分析17例（共28个病灶）经手术病理证实或临床综合诊断确诊为囊性脑转移瘤的CT和MRI表现。结果：多发2例，单发15例。病灶呈圆形或椭圆形。位于大脑半球14例，其中位于脑皮质及皮质下区13例。单囊型10例，大囊小结节型4例。位于小脑呈大囊小结节型3例。CT平扫表现为囊性低密度，边缘有环状略高密度包膜15例和包膜毛糙2例。囊内液体呈长T1低信号，长他高信号。增强扫描病灶明显增强呈环状增强15例，结节状增强4例。病灶周围无明确水肿2例、中度水肿10例和重度水肿5例。结论：囊性脑转移瘤多位于脑皮质及皮质下区，CT、MRI具有一定的特征性表现，结合临床有助于正确诊断。     

局灶性机化性肺炎的CT表现及特征

目的：探讨局灶性机化性肺炎的CT特点及诊断价值。方法：回顾性分析45例经手术病理证实的局灶性机化性肺炎的临床资料及CT表现。结果：45例按病灶形态分为结节型（16例）、肿块型（15例）、浸润型（8例）和实变型（6例）。CT表现：7例边缘清晰光整，10例呈锯齿样改变，12例见有细毛刺，8例边缘模糊，8例边缘呈不规则样。10例结节型和10例肿块型病灶行平扫加增强。结节型：病灶均匀强化3例，环状强化3例，不规则强化2例，不增强2例；肿块型：病灶均匀强化4例，环状强化3例，不规则强化2例，不增强1例。6例环状强化病灶内有液化坏死。16例病灶内见支气管充气征，12例见支气管血管束异常，20例病灶位于胸膜旁。结论：局灶性机化性肺炎CT表现多样，但有一定的特征性，CT诊断符合率较高。     

Imaging findings in intracranial aspergillosis

RATIONALE AND OBJECTIVES: The authors' purpose was to elucidate the various computed tomographic (CT) and magnetic resonance (MR) imaging findings in intracranial aspergillosis. MATERIALS AND METHODS: Retrospective analysis of cranial imaging findings was performed in eight proved cases of central nervous system aspergillosis. The patients ranged in age from 17 to 75 years. Four patients were immunocompromised, and four were immunocompetent. CT was performed in all eight patients, and MR imaging in five. RESULTS: Six patients (75%) had multiple lesions seen on the imaging studies, with a total of 27 focal brain lesions demonstrated. The lesions were most commonly seen in the cerebral hemispheres (n = 21), with lesser involvement of the basal ganglia (n = 2) and the posterior fossa (n = 4). Seven lesions were hemorrhagic on CT and/or MR images. There was a correlation between lesion size and hemorrhage, with hemorrhage more likely in larger lesions (>15 mm). At pathologic examination, foci of hemorrhage were noted within both infarcts and abscesses. Enhancement was noted in five lesions, four of which were confirmed abscesses. Contrast enhancement of the lesions was vague and week in immunocompromised patients but solid and strong in immunocompetent patients. There were 18 lesions without hemorrhage or enhancement; they were either infarcts or abscesses at pathologic examination. Some of these small nonhemorrhagic nonenhancing brain lesions in the subcortical white matter mimicked lacunar infarcts. CONCLUSION: Typical imaging findings of intracranial aspergillosis include multifocal lesions involving the cerebral hemispheres, with hemorrhage in approximately 25% of lesions. Lesional contrast enhancement tends to be stronger in immunocompetent hosts.     

菲立磁增强MRI检测肝脏占位病变与三期动态增强CT扫描的比较研究

目的　比较菲立磁增强MRI和增强CT扫描在肝脏实性占位病变检测中的应用价值。方法　对 18例肝内局灶性占位患者行MR平扫及菲立磁增强扫描。观察肝脏与病灶信号强度变化 ,形态及数目 ,比较增强前后T2 WI病灶及肝脏的信噪比 (SNR)及对比噪声比 (CNR) ,做出MRI定性诊断 ,并与增强CT扫描诊断进行比较。其中肝细胞肝癌 4例 ,复发性肝癌 4例 ,转移瘤 4例 ,肝血管瘤 6例。结果　菲立磁增强明显降低正常肝组织信号强度 ,而恶性肿瘤的信号强度无强化 ,病灶—肝脏信噪比增加可清晰显示病变 ,并发现新病灶。肝血管瘤的血池效应与增强CT扫描比较有鉴别诊断意义。结论　做为增强CT扫描和Gd -DTPAMR增强的补充方法 ,SPIO增强MRI对肝脏占位病变的显示 ,小病灶发现和定性诊断中有重要的临床意义     

Atypical focal nodular hyperplasia of the liver: imaging features of nonspecific and liver-specific MR contrast agents

OBJECTIVE: The objective of our study was to describe the functional and differential uptake features of atypical focal nodular hyperplasia using different MR contrast agents and to evaluate their potential role in the diagnosis and characterization of focal nodular hyperplasia. MATERIALS AND METHODS: Contrast-enhanced MR images of 45 patients with 85 focal nodular hyperplasia lesions were retrospectively reviewed. In these patients, sonographic findings were nonspecific (n = 37), or CT features were inconclusive (n = 8). Non-liver specific gadolinium chelates were used in 18 patients (48 lesions) suspected of having either focal nodular hyperplasia or hemangioma. The following liver-specific agents were used in patients with suspected focal nodular hyperplasia or metastases: mangafodipir trisodium, 30 patients (55 lesions); ferumoxides, six patients (16 lesions); and SHU 555 A, six patients (six lesions). Individual lesions were quantified by signal intensity and assessed qualitatively by homogeneity, contrast enhancement, and presence of a central scar. RESULTS: At unenhanced MR imaging, the triad of homogeneity, isointensity, and central scar was found in 22% of the focal nodular hyperplasia lesions. On mangafodipir trisodium-enhanced T1-weighted images, all focal nodular hyperplasia lesions showed contrast uptake: in 64% of the lesions, uptake was equal to parenchyma; 25%, greater than the parenchyma; and 11%, less than the parenchyma. On iron oxide-enhanced T2-weighted images, all focal nodular hyperplasia lesions showed uptake of the contrast agent, but contrast uptake in the lesions was less than in the surrounding parenchyma. Dynamic gadolinium chelate-enhanced MR imaging showed early and vigorous enhancement of focal nodular hyperplasia lesions with rapid washout in 88%. Atypical imaging features of the lesions included hyperintensity on T1-weighted images, necrosis and hemorrhage, and inhomogeneous or only minimal contrast uptake. CONCLUSION: For patients in whom the diagnosis of focal nodular hyperplasia cannot be established on unenhanced or gadolinium-enhanced MR imaging, homogeneous uptake of liver-specific contrast agent with better delineation of central scar may help to make a confident diagnosis of focal nodular hyperplasia.     

Castleman病的影像学表现与手术、病理对照分析

目的探讨Castleman病的CT、MR及血管造影的影像学特征,以期在术前做出正确诊断。方法回顾性分析经手术、病理证实的16例Castleman病患者的临床、影像、手术及病理资料。结果 16例患者按病理分型:透明血管型12例,浆细胞型1例,混合型3例。按临床分型:为局灶型13例,多中心型3例。影像学表现:CT扫描15例,平扫表现病灶为直径1.3～20 cm[平均(6.21±4.75)cm]大小的单发、多发结节或软组织肿块,其中1例盆腔病变内可见簇状钙化;增强扫描病灶动脉期显著强化且与动脉几乎同步强化;浆细胞型病灶呈轻-中度强化。MR检查4例,MRI 2例,1例考虑盆腔海绵状血管瘤可能,1例后纵隔囊性占位,MRI+MRA 1例,诊断Castleman病,MRA 1例诊断为颈动脉体瘤,此例同时做数字减影血管造影,诊断为甲状腺实质性肿瘤。结论透明血管型Castleman病的影像表现与病理类型密切相关,CT及MRI增强表现有其特征,具有重要的诊断价值。而浆细胞型Castleman病影像表现不典型,术前诊断困难。     

肝脏局灶性结节增生的螺旋CT和MRI诊断

目的 :分析肝脏局灶性结节增生 (FNH)平扫和动态增强的螺旋CT、MRI表现 ,提高FNH诊断符合率。方法 :对 13例经手术病理证实的FNH影像学表现进行回顾性分析。螺旋CT检查 8例 ,MRI检查 6例 ,其中 1例同时做CT和MRI检查。结果 :8例CT平扫病灶均呈低密度 ,均匀或不均匀。增强动脉期扫描除中心疤痕外 ,所有病灶均有明显均匀强化 ,其中 4例还可见到病灶中心或周边增粗、扭曲的动脉。门脉期和延迟期扫描 4例呈略高密度、4例病灶呈等密度或略低密度 ,4例伴有中心疤痕者均有延迟强化。MRI检查 6例 ,病灶均呈不均匀略长或等T1及T2 信号 ,增强动脉期呈明显强化 ,门脉期及延迟期呈等或略高强化 ,4例MRI平扫显示中央瘢痕者有延迟强化。结论 :平扫和动态增强螺旋CT、MRI能较全面显示FNH的病理特征和血供特点 ,明显地提高与其它富血管恶性肿瘤的鉴别诊断能力     

出血坏死性鼻息肉的CT和MRI诊断

目的 探讨出血坏死性鼻息肉的CT和MRI表现.方法 回顾性分析17例经病理证实的出血坏死性鼻息肉的影像资料.其中14例行CT检查,16例行MR检查,15例同时行MR增强检查.结果 17例病变均以上颌窦口为中心向鼻腔及上颌窦内生长,边缘清晰,16例形态不规整,呈浅分叶状,仅1例呈卵圆形.CT表现:14例病变表现为密度不均匀的软组织肿块影,2例分别在病变周边及内部见到条形及结节状高密度影,邻近骨质均呈压迫、吸收改变,局部骨质不连续,以上颌窦内壁最常见.MRI表现:16例病变内部在T_1WI上为低信号(与脑灰质相比),T_2WI上为高信号,14例同时伴有线样的低信号分隔;15例病变周边可见到T_1WI为等信号、T_2WI为低信号的不规则环形影围绕;15例行增强检查的病变呈不均匀性明显强化,强化部分形态各异,10例内部为多发结节状强化,4例为斑片状强化,1例强化外观似叶片状,而T_2WI上的低信号环不强化.4例病变的鼻腔侧周边可见边缘清楚的囊状液体信号影,向前至鼻前庭,向后达后鼻孔区,增强后不强化.11例行动态增强扫描,其中7例时间-信号强度曲线(TIC)呈持续上升型;4例呈速升缓降型.结论 MRT_2WI上内部的不均匀高信号为低信号围绕以及增强后结节状、斑片状的强化特征均是出血坏死性鼻息肉特异的MRI表现,而CT有助于判断病变性质,明确诊断有一定困难,MRI应是出血坏死性鼻息肉的首选检查方法.     

肝局灶性病变CT与MRI动态增强对照研究

目的:探讨肝局灶性病变在CT和MRI动态增强中的影像差异及其原因,以提高对CT及MRI各自动态增强表现的认识。方法:搜集17例肝脏局灶性病变患者的临床资料,其中7例肝细胞肝癌,5例海绵状血管瘤,2例腺瘤,2例局灶结节性增生,1例转移瘤。全部病例均分别行CT及MRI的平扫和三期动态增强扫描;MRI采用SE序列加快速扰相梯度回波序列,将CT和MR动态增强图像进行对照观察,包括动态增强各期的强化范围、强化方式和强化幅度,强化幅度的比较用病灶密度(信号)与肝脏密度(信号)的比值进行比较。结果:肝癌、腺瘤和局灶结节性增生在CT与MRI上强化范围相似。1例肝癌动脉期强化幅度MRI大于CT,3例肝癌和2例局灶结节性增生门脉期及延迟期强化幅度MRI大于CT,2例腺瘤增强各期强化幅度MRI均大于CT,以动脉期差异最大。5例海绵状血管瘤强化范围动脉期及门脉期MRI大于CT,延迟期则相仿。1例转移瘤CT增强各期均未见明显强化,MRI门脉期及延迟期可见环状强化。结论:肝局灶性病变CT与MRI动态增强表现存在一定的差异,主要表现为部分病变增强各期强化幅度MRI大于CT,尤以动脉期差异最大;部分病变增强范围MRI大于CT。     

Brain microhemorrhages detected on T2*-weighted gradient-echo MR images

BACKGROUND AND PURPOSE: Multifocal microhemorrhages have been reported to be commonly found in the brain of patients with systemic hypertension and spontaneous brain hemorrhage. The factors associated with these lesions detected on T2*-weighted gradient-echo images were examined to determine whether these lesions serve to indicate different types of microangiopathy and to predict a patient's risk for symptomatic hemorrhage. METHODS: The study population consisted of 2164 patients who underwent 2416 consecutive brain MR imaging studies performed during 3 years. The patients with intracerebral hemorrhages due to vascular malformations, neoplasms, trauma, or intracranial surgery and those with incomplete medical records were excluded; 2019 cases were analyzed. RESULTS: The overall incidence of microhemorrhages was 9.8%, predominantly in the lentiform nucleus (n = 96), thalamus (n = 88), and cortical-subcortical region (n = 93). Presence of microhemorrhages had the highest significant correlation with history of hemorrhagic stroke (P <.0001); advancing age, hypertension, and prominent white matter hyperintensity on T2-weighted images had the next highest significant correlation. Cortical-subcortical microhemorrhages were more frequently observed in patients who had previous lobar hemorrhagic stroke (P <.005). Among 139 patients with microhemorrhages who could be clinically followed up for more than 1 month, four (2.9%) had new hemorrhagic stroke. CONCLUSION: The presence of microhemorrhages may be not only a direct marker of bleeding-prone small-vessel diseases but also an indicator of different types of microangiopathy and a predictor of further hemorrhagic stroke.     

肺癌单发脑转移瘤的磁共振表现

目的:探讨肺癌单发脑转移瘤(SBM)的MRI表现,提高对单发脑转移瘤的诊断准确性.方法:回顾性分析经手术病理和临床证实的39例肺癌单发脑转移瘤的MRI表现,分析单发瘤体发生的部位、大小、形态、瘤体出血、瘤周水肿程度和瘤体的强化特点.结果:39个SBM,发生于幕上32例,其中31例瘤体位于皮质和皮质下区,7例位于幕下.增强扫描示病灶呈结节状强化18例,环状强化5例,囊实性强化16例.肺腺癌转移瘤内出血4例(4/5),肺鳞癌脑转移瘤出现囊变或囊实性强化11例(11/21).中重度水肿大多出现在≥2cm的实性或囊实性强化的瘤体(22/39)中.结论:肺癌单发脑转移瘤的MRI表现具有一定的特征性,MRI增强扫描对诊断单发脑转移瘤有重要价值.