肝脏血管平滑肌脂肪瘤的CT、MRI分型诊断价值及其病理基础

目的:探讨肝脏血管平滑肌脂肪瘤的CT、MRI分型诊断价值及其病理基础.方法:收集经临床和病理资料证实的肝脏血管平滑肌脂肪瘤21例,分析其CT、MRI征象,探讨CT、MRI对各型的分型诊断价值及其病理基础.结果:21例均行CT扫描,其中12例行MR检查.血管瘤型4例,病理上以粗大扭曲的异常血管或血管瘤为主,CT、MR增强扫描异常血管或血管瘤动脉期呈明显强化,门脉期强化程度仍高于同期肝实质.肌瘤型3例,病理上以平滑肌成分为主,脂肪成分很少(<10%).CT平扫为较均匀低密度,MRI T1WI呈低信号,T2WI呈稍高信号;CT、MRI增强扫描动脉期呈明显强化,门脉期、延迟期呈持续强化.脂肪瘤型5例,病理上以脂肪成分为主(≥70%),CT、MRI显示脂肪密度或信号.混合型9例,CT平扫为含有脂肪的混杂密度,MRI T1WI病灶主体呈不均匀低信号,脂肪成分呈高信号,T2WI呈混杂高信号,CT、MRI增强扫描其内软组织成分动脉期呈明显强化,门脉期仍有强化.病理上血管、平滑肌、脂肪3种成分比例接近(其中脂肪成分占10%～70%).免疫组化:上述21例均显示HMB45(+)、SMA(+).结论:CT、MRI能较好地反映肝脏血管平滑肌脂肪瘤的分型和各型的病理特征,具有一定的诊断特异性.     

头颈部血管瘤及血管畸形的CT、MRI诊断

目的:分析头颈部血管瘤及血管畸形的CT、MRI表现,探讨其诊断及鉴别诊断价值。方法:搜集经手术病理或DSA证实,临床及影像资料完整的47例头颈部血管瘤或血管畸形病例的资料,对其进行回顾性分析。CT检查33例,MRI检查14例。结果:海绵状血管瘤21例,T1WI呈均匀等或低信号,T2WI呈高信号,增强扫描呈中等不均匀强化并可见纡曲血管强化;CT平扫呈不均匀等密度、囊状低密度,3例可见圆点状静脉石,增强扫描轻至中等度强化,其中6例见线条状粗大纡曲血管影。蔓状血管瘤23例,病变弥漫,无明显边界。T1WI呈等信号,T2WI呈不均匀高信号,其内见粗大的流空血管影及低信号静脉石,增强扫描明显不均匀强化;CT平扫等密度,见高密度圆点状静脉石,增强明显强化,可见蚯蚓状粗大血管团。淋巴管瘤3例,边界清楚,平扫为低密度,增强扫描无明显强化。结论:CT及MRI可较好显示头颈部血管畸形,蔓状血管瘤为动静脉畸形或高流速血管畸形,影像见粗大纡曲的血管影。低流速的静脉畸形、淋巴管畸形须与头颈部其它囊性病变鉴别。     

血管畸形和中间性血管肿瘤的影像鉴别诊断

目的 探讨血管畸形和血管中间性肿瘤的影像鉴别诊断.方法 回顾性分析58例血管畸形和血管中间性肿瘤患者的影像表现.结果 血管畸形42例,CT与MRI显示病变边缘均呈不规则形,边界清晰,CT与X线显示5例病变对邻近骨质产生压迫改变.31例MRI中,T2WI 3例旱较高信号(接近脂肪信号),28例呈混杂高信号(高于脂肪信号),其中20例在病变区显示圆形血管样高信号.血管中间性肿瘤16例,CT与MRI显示7例肿块呈类圆形,边界规则,8例肿块呈分叶状,1例边缘呈"蟹爪"状,5例瘤周可见水肿和占位效应,CT与x线显示3例周围骨质产生侵蚀改变,2例肿瘤在骨内可形成溶骨性破坏.11例MRI中,T2WI11例呈较高信号.结论 血管畸形和血管中间性肿瘤影像表现不同.     

睾丸生殖细胞肿瘤的MRI诊断

目的：探讨睾丸生殖细胞肿瘤的 MRI 表现,提高对该疾病的 MRI 诊断水平。方法回顾性分析经手术病理证实的25例睾丸生殖细胞肿瘤患者临床及 MRI 资料,所有病例均行 MRI 平扫,其中16例行动态 MRI 增强扫描。利用 MRI 对睾丸肿瘤的大小、形态、信号特点、毗邻关系、强化方式及肿瘤血管情况进行评估,并与病理对照。结果25例睾丸生殖细胞肿瘤中,精原细胞瘤10例,其中 T2 WI 呈均匀低信号8例,稍低信号2例,增强扫描轻度结节样强化5例,明显均匀强化2例,其中4例可见纤维间隔强化;卵黄囊瘤4例,T1 WI 呈等低信号,T2 WI 呈稍高信号,增强扫描后肿瘤呈渐进式强化;成熟型畸胎瘤、表皮样囊肿、混合性生殖细胞肿瘤各3例,T1 WI 呈混杂低信号,T2 WI 呈混杂高信号;胚胎性癌2例,T1 WI 呈等低信号,T2 WI 呈混杂低信号,其内可见出血信号,增强扫描呈分隔强化。结论MRI 对睾丸生殖细胞肿瘤诊断正确率较高,对其病理分型、分期及鉴别诊断具有重要价值。     

原发性椎管内硬膜外占位性病变的MRI表现

目的 :探讨原发性椎管内硬膜外占位性病变的MRI特点。方法 :分析21例椎管内硬膜外占位性病变的MRI表现。肿瘤性病变13例,其中淋巴瘤6例,脂肪血管瘤4例,海绵状血管瘤3例;非肿瘤性病变8例,其中椎间盘髓核游离6例,自发性血肿2例。结果:8例原发性椎管内硬膜外占位性病变呈包鞘状包绕硬膜囊。6例淋巴瘤T2WI呈均匀略低信号,增强扫描后明显均匀强化,2例合并邻近骨质破坏。3例脂肪血管瘤与3例海绵状血管瘤主要位于背侧硬膜外。4例脂肪血管瘤T2WI呈高信号,T1WI病灶内可见高信号脂肪组织;3例海绵状血管瘤T1WI呈等或低信号,T2WI呈高信号;所有脂肪血管瘤与海绵状血管瘤增强扫描均明显强化。6例椎间盘髓核游离均位于腹侧硬膜外,呈结节状,T2WI呈低信号,增强扫描呈周边环形强化。2例自发性血肿信号复杂,增强扫描后不强化。结论:原发性椎管内硬膜外占位性病变有一定的MRI特点,MRI能进行有效的诊断与鉴别。     

软组织脉管畸形的MRI诊断

目的 探讨MRI对软组织脉管畸形的诊断价值.资料与方法 回顾性分析575例脉管畸形患者的MRI表现.结果 490例血管畸形,T1WI等信号88例,混杂信号402例;T2WI不均匀高信号475例,较均匀高信号15例,圆形血管样高信号210例,在病变的边缘可见尖角样改变216例.43例淋巴管畸形,T1WI等信号2例,混杂信号36例;T2WI不均匀高信号38例,5例T1WI、T2WI表现为脂肪增厚,另见囊状灶26例.42例血管、淋巴管混合畸形,T1WI等信号2例,混杂信号40例;T2WI不均匀高信号42例.结论 MRI能反映脉管畸形的特征,对其诊断与鉴别诊断有重要价值.     

手部常见软组织肿瘤的MRI表现

目的 :探讨手部常见软组织肿瘤的MRI特点。方法 :对53例经病理确诊的手部常见软组织肿瘤的临床资料及MRI特点进行回顾性分析,53例均行MRI平扫,其中38例行MRI增强扫描。结果:53例中腱鞘巨细胞瘤17例,血管瘤12例,血管球瘤11例,腱鞘囊肿8例,脂肪瘤5例。MRI表现:腱鞘巨细胞瘤T1WI多呈等低信号,T2WI呈高低混杂信号,边缘多可见低信号包膜影,增强扫描多明显强化;血管瘤T1WI多呈以稍高信号为主的混杂信号,PDWI多呈不均匀高信号,瘤内多可见出血,增强扫描不均匀明显强化;血管球瘤T1WI呈等低信号,PDWI呈高信号,增强扫描明显均匀强化;腱鞘囊肿T1WI呈稍低信号,PDWI呈高信号,部分瘤内可见线状低信号分隔影,增强扫描包膜强化;脂肪瘤T1WI呈高信号,PDWI及STIR呈低信号。结论 :手部常见软组织肿瘤多具有典型的MRI表现,MRI可作为诊断手部软组织肿瘤的首选方法。     

单纯脊柱硬膜外病变12例报告及文献复习

目的 探讨单纯脊柱硬膜外病变的诊断和鉴别诊断.资料与方法 总结12例经手术病理证实的单纯硬膜外病变的MRI表现,并复习文献.结果 非创伤性硬膜外血肿的MRI表现特点是在T1WI上呈等、高信号,T2WI上呈高信号,或有低信号而呈混杂信号,多数不强化.海绵状血管瘤为T1WI上与脊髓等信号,T2WI上为极高的均匀信号,如有出血,则信号不均匀.病变有明显强化.如果肿块内有脂肪及血管成分,血管成分有明显强化,而脂肪成分不强化,则可能是血管脂肪瘤.T1WI和T2WI上与脊髓等信号的病变比较多,常见的有白血病、感染、转移瘤、脊膜瘤、骨髓瘤.较大囊肿应考虑硬膜外蛛网膜囊肿及棘球蚴囊肿,但以前者为多见.结论 MRI可以清楚显示单纯脊柱硬膜外病变的特点,并能对多数病例做出诊断.     

椎管内海绵状血管瘤的MRI诊断及鉴别诊断

目的 探讨MRI对椎管内海绵状血管瘤的诊断及其鉴别诊断价值.方法 9例经手术病理证实的椎管内海绵状血管瘤行磁共振平扫检查,同时行增强扫描,分析其影像表现.结果 5例位于胸段、2例位于颈段、2例位于腰骶段.海绵状血管瘤的MRI表现:6例呈等T1WI信号,2例呈长T1WI信号,1例呈短T1WI信号,9例呈长T2WI信号影,增强扫描4例明显均匀强化,2例不均匀强化,3例无明显强化.MRI信号因海绵状血管瘤反复出血不同时期出血成分沉积及血栓形成、胶质增生而表现多样.结论 MRI对椎管内海绵状血管瘤的术前确诊及鉴别诊断具有重要价值.     

四肢深部软组织血管瘤和血管畸形的X线及MRI表现

目的：探讨四肢深部软组织血管瘤和血管畸形的 X 线及 MRI 表现。方法回顾性分析经手术病理及 DSA 证实的89例四肢深部软组织血管瘤和血管畸形患者的临床、影像资料,其中89例均行 X 线平片检查,33例行 MRI 检查。结果 X 线检查中,骨质及软组织影未见异常者54例(60.7%),软组织异常者14例(15.7%),可见静脉石者30例(33.7%);骨质异常者32例(36.0%),其中伴骨膜反应者13例,皮质破坏16例,髓腔受累者10例,三者均受累者为7例弥漫性病灶。MRI 图像上,病灶呈蜂窝状或海绵状,T1 WI 上呈等低信号者25例(75.8%),低信号5例(15.2%),不均匀稍高信号3例(9.0%);T2 WI 上病灶为不均匀高信号伴低信号分隔,范围及边界显示清楚,其中9例内部可见低信号区伴血管流空影;检出静脉石10例(30.3%),呈低信号;增强后病变不均匀明显强化。骨质异常者18例(54.5%),均可见病灶紧邻骨质或呈半包绕、包绕改变,其中12例髓腔内可见异常信号影,3例为迂曲血管流空影。在15例(45.5%)骨质无改变患者中,3例病灶邻接骨质,余12例病灶与骨间隔以脂肪或肌肉组织。结论四肢深部软组织血管瘤和血管畸形可引起邻近骨质的异常,掌握其 X 线及 MRI 表现特征,有助于提高对本病的诊断与鉴别诊断能力。     

Idiopathic and diabetic skeletal muscle necrosis: evaluation by magnetic resonance imaging

Objective Idiopathic and diabetic-associated muscle necrosis are similar, uncommon clinical entities requiring conservative management and minimal intervention to avoid complications and prolonged hospitalization. An early noninvasive diagnosis is therefore essential. We evaluated the magnetic resonance imaging (MRI) characteristics of muscle necrosis in 14 patients, in eight of whom the diagnoses were confirmed histologically.Design and patients Two experienced musculoskeletal radiologists performed retrospective evaluations of the MRI studies of 14 patients with the diagnoses of skeletal muscle infarction. In 10 cases gadolinium-enhanced (T1-weighted fat-suppressed) sequences were available along with T1-weighted, T2-weighted images and STIR sequences, while in four cases contrast-enhanced images were not available.Results Eight patients had underlying diabetes and in six patients the cause of the myonecrosis was considered idiopathic. T1-weighted images demonstrated isointense swelling of the involved muscle, with mildly displaced fascial planes. There was effacement of the fat signal intensity within the muscle. Fat-suppressed T2-weighted images showed diffuse heterogeneous high signal intensity in the muscles suggestive of edema. Perifascial fluid collection was seen in eight cases. Subcutaneous edema was present in seven patients. Following intravenous gadolinium administration, MRI demonstrated a focal area of heterogeneously enhancing mass with peripheral enhancement. Within this focal lesion, linear dark areas were seen with serpentine enhancing streaks separating them in eight cases. In two cases, a central relatively nonenhancing mass with irregular margins and peripheral enhancement was noted. The peripheral enhancement involved a significant part of the muscle. No focal fluid collection was noted.Conclusions We believe that the constellation of imaging findings on T1- and T2-weighted images and post-gadolinium sequences is highly suggestive of muscle necrosis. We consider certain specific findings on gadolinium-enhanced images to be characteristic. The findings reported here should provide radiologists with useful information in making the diagnosis of skeletal muscle necrosis without resorting to invasive procedures.     

Characteristic MR findings of cervical pregnancy

The aim of this study was to define the characteristic MR findings of cervical pregnancy. Twelve patients with cervical pregnancy underwent MRI because of difficulty in the diagnosis by ultrasonography, human chorionic gonadotropin assessment, and other clinical evaluations. The assessment of MRI included size and location of the lesion, margin, MR signal intensity, rim of low-signal intensity, enhancement pattern, appearance of enhancing solid component, parametrial change, endometrial change, pelvic fluid collection, and ovarian change. All cases showed ill-marginated mass with very heterogeneous signal intensity on T2-weighted images, irregular internal high-signal intensities on T1-weighted images, a partial or circumferential rim of low-signal intensity, dense irregular peripheral enhancement and enhancing papillary solid components with accompanying tubular signal voids, and variably increased parametrial vascularities. This heterogeneous hemorrhagic mass with densely enhancing papillary solid components may be the typical MR finding for cervical pregnancy. J. Magn. Reson. Imaging 2001;13:918-922.     

Magnetic resonance imaging characteristics with pathological correlation of cavernous malformation in cavernous sinus

OBJECTIVE: To analyze extracerebral cavernous malformation located in the cavernous sinus and correlate their magnetic resonance imaging (MRI) features to pathological findings. MATERIALS AND METHODS: Nineteen patients (5 men and 14 women; mean age, 50.6 years; range, 32-71 years) with surgically verified cavernous malformations in the cavernous sinus were reviewed. MRI including T1-weighted, T2-weighted, and postcontrasted T1-weighted imaging was carried out in all instances with a 1.5-T superconductive system (Signa; General Electric Medical Systems, Milwaukee, WI). RESULTS: All these lesions measured from 2.5 cm to 6 cm (average, 4.3 cm) with 13 lesions located to the right side and 6 to the left side. Magnetic resonance images showed that 18 cases were hypointense to white matter on T1-weighted images with only one case showed mixed hypointensity and hyperintensity. On T2-weighted images, 17 cases showed marked homogeneous hyperintensity, 1 case showed marked hyperintensity with some signal void structures and 1 with mixed intensity. Marked homogeneous enhancement after contrast material administration was found in 7 cases, and the remaining 12 showed marked heterogeneous enhancement. Pathologically, these lesions can be classified as type A, type B, and type C. Type A was sponge-like with intact pseudocapsule; type B was mulberry-like with the pseudocapsule incomplete or absent; and type C was composed of both mulberry-like composition and sponge-like composition. Lesions with homogeneous contrast enhancement on MRI correlated with type A pathological findings, whereas those with heterogeneous enhancement correlated with type B and type C pathological findings. Asymmetrical dumbbell-shaped masses of 13 cases involving the sellar and round masses of 6 cases with 2 protruding into the sellar were found. All of the cavernous malformations displaced the adjacent temporal lobe without adjacent brain edema. The internal carotid arteries were displaced or encased in all cases. CONCLUSIONS: If a well-demarcated, homogeneous high signal intensity lesion on T2-weighted images with a dumbbell configuration involving both parasellar and sellar regions with marked heterogeneous or homogeneous enhancement is found, the diagnosis of cavernous sinus cavernous malformation should be entertained.     

MRI of tuberculous pyomyositis.

PURPOSE: The purpose of this article is to describe the findings of MRI in tuberculous pyomyositis (PM). METHOD: The MR images of four proven cases of tuberculous PM were retrospectively reviewed and analyzed with clinical and laboratory findings. The location, signal intensity on T1- and T2-weighted spin echo images, presence of abscess, signal intensity of peripheral rim, patterns of contrast enhancement, and associated findings were evaluated. RESULTS: On MR images, all cases demonstrated low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in a single muscle. Abscess was seen in all cases. Peripheral rim showed subtle hyperintensity on T1-weighted images and hypointensity on T2-weighted images. After gadolinium infusion, peripheral rim enhancement was observed in all cases. Cellulitis was associated in one case. The patients clinically presented with a palpable mass of long duration. CONCLUSION: Tuberculous PM shows characteristic findings of a well demarcated abscess with rim enhancement at MRI and can be distinguished from other soft tissue masses.     

单纯疱疹病毒性脑炎的MRI诊断

目的：回顾分析单纯疱疹病毒性（ＨＳＶ）脑炎的ＭＲ成像表现，为临床早期诊断和治疗提供依据。材料和方法：１０例（男４例，女６例；平均年龄３９．５岁）经脑脊液ＰＣＲ证实的ＨＳＶ脑炎患者，采用高磁场（１．０Ｔ）磁共振扫描仪，以自旋回波序列行横断／冠状面Ｔ１加权、质子加权、Ｔ２加权成像和注造影剂后Ｔ１加权成像。结果：１０例中，８例ＭＲ像存在异常信号（广泛、多发、双侧者６例，局灶改变２例）。Ｔ１加权像呈均质低信号５例，该５例在Ｔ２加权像呈均质高信号，提示病理上病灶区坏死，伴周围水肿；３例Ｔ１加权像呈片状低信号内伴脑回状高信号，Ｔ２加权像呈不均质信号，病理上代表出血；增强后Ｔ１加权像呈脑回状强化３例，１例呈结节状改变。结论：以颞叶、岛叶、额底分布为主（尤其为扣带回受累）的多发病灶、伴脑回状出血和强化是ＨＳＶ脑炎的特征性ＭＲ成像表现。不典型表现须与脑瘤、脑梗塞和其它类型病毒性脑炎鉴别诊断。     

Differentiation of hepatic hemangiomas from metastases by dynamic contrast-enhanced MR imaging

Twenty-nine patients with hepatic hemangiomas (n = 14) and hepatic metastases (n = 15) underwent magnetic resonance (MR) imaging prior to and after an intravenous bolus injection of Gd-diethylenetriamine pentaacetic acid (0.2 mmol/kg). Before contrast application, a T2-weighted spin echo sequence (SE 1,600/105) and a T1-weighted gradient echo sequence (GE 315/14/90 degrees pulse angle) were performed. Beginning with injection of the contrast agent, a dynamic study was conducted for 10 min using a moderately T1-weighted gradient echo sequence (GE 40/14/40 degrees) with an acquisition time of 10.2 s per image. Delayed (11 min) and late (60 min) postcontrast images were obtained using a T1-weighted sequence (GE 315/14/90 degrees). In the dynamic study (0-10 min) the hemangiomas were characterized by peripheral contrast enhancement and a subsequent hyperintense fill-in. The metastases showed very mixed patterns of enhancement after contrast administration, and their signal intensity remained low compared with that of the hepatic tissue. In the delayed postcontrast examination (11 min) the hemangiomas had a very high and homogeneous signal intensity and the metastases were characterized by an inhomogeneous, hypointense to isointense signal. The contrast between tumor and liver [signal-difference-to-noise ratio (SD/N)] was higher for all hemangiomas than it was for the metastases. In the T2-weighted precontrast examination, on the other hand, five hemangiomas and seven metastases showed an overlap in the SD/N. The late postcontrast images (60 min) did not yield any further diagnostic information. We conclude that the combination of a dynamic MR study with delayed postcontrast T1-weighted imaging is a useful method of diagnosing hepatic hemangiomas.     

Atypically enhancing hepatic cavernous hemangiomas: high-spatial-resolution gadolinium-enhanced triphasic dynamic gradient-recalled-echo imaging findings

We retrospectively investigated the appearance and frequency of atypically enhancing cavernous hemangiomas with high-spatial-resolution (512x224 matrix) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) MR images. Images of 132 hepatic cavernous hemangiomas (ranging in size from 4 to 72 mm; mean size 17.2 mm) in 95 patients (42 men and 53 women; age range 25-85 years; mean age 54 years) were retrospectively reviewed by two independent radiologists. Forty (30%) of 132 lesions atypically enhanced. Smaller hemangiomas (< or =15 mm) more frequently (29%) showed early entire enhancement with or without arterio-portal shunting in the hepatic arterial-dominant phase ( p<0.001); most of them showed hyperintense complete fill-in in the equilibrium phase and were readily characterized. "Bright dot" or minimal peripheral enhancement in the equilibrium phase was seen in a small number of lesions (6% each). With T2-weighted images, 130 (98%) lesions showed moderately to very high signal intensity and only 2 (2%) with minimal peripheral enhancement showed hyperintensity of slight degree. The high-spatial-resolution dynamic GRE images clearly revealed minute enhancement characteristics of hemangiomas. Although moderately to very high signal intensity with T2-weighted MR images is informative for the diagnosis of most cavernous hemangiomas, when a lesion shows minimal peripheral enhancement in the equilibrium phase and hyperintensity of slight degree with T2-weighted images, further follow-up or biopsy may be warranted to discriminate hypovascular metastases.     

Magnetic resonance imaging of pyomyositis in 43 cases

PURPOSE: To describe the magnetic resonance imaging (MRI) findings in pyomyositis. METHODS AND MATERIALS: Forty-three patients with proven muscle infection (30 males, 13 females) ranging in age from 14 to 86 years (mean 42 years) were studied with MRI. The initial clinical diagnose were soft tissue infection (n=27), neoplasm (n=12), thrombophlebitis (n=3), and lymphedema (n=1). Spin-echo T1- and T2-weighted images were obtained in all cases and STIR sequence in 6. Spin-echo T1-weighted images after Gd-DTPA injection were obtained in 16 cases. The signal intensity findings, the extent of the abnormalities in the soft tissue (muscle, fascial and subcutaneous involvement), the presence of fluid collections, and the involvement of neighbouring bone and joint were reviewed retrospectively. RESULTS: A hyperintense signal on T2-weighted and STIR images were detected in all patients. Fluid collections were seen in 21 cases as localized areas of hypointensity on the T1-weighted images, and highly hyperintense areas on the T2-weighted images. In four patients a rim of high signal intensity was seen around the fluid collection on the T1-weighted images. On contrast-enhanced T1-weighted images there was diffuse enhancement in the patients without fluid collections that was heterogeneous in seven and homogeneous in two. After Gd-DTPA all fluid collections showed a central area without enhancement and a well-defined enhancing peripheral rim. Involvement of adjacent structures included subcutaneous tissue (n=25), bone marrow (n=14), fascial planes (n=15) and joints (n=11). CONCLUSION: MRI is useful in the assessment of pyomyositis and in determining the location and extension. A hyperintense rim on unenhanced T1-weighted images and peripheral enhancement after Gd-DTPA are useful for identifying the number, size, and location of soft-tissue abscesses.