颅底型垂体瘤CT、MRI影像分析

目的　探讨颅底型垂体瘤的CT、MRI影像特征。方法　分析 16例颅底型垂体瘤 (skullbase typepituitaryadenoma,SBPA)的CT、常规MRI表现 ,以及动态增强MRI与病理学资料 ;与 9例颅底脊索瘤 (chordomaoftheskullbase ,CSB)比较 ,观察二者在CT、常规MRI征象和时间信号 曲线类型、强化峰值时间、平均强化速率方面的差异。结果　SBPA和CSB的CT表现相似 ,鉴别困难。二者T1WI均为稍低信号 ;T2 WI上SBPA为稍高信号 ,CSB为显著高信号 ,二者间差异具有非常显著性意义 (P <0 0 0 1)。SBPA于T2 WI高信号背景上散布高信号小泡影 ,小泡影与背景的T2 WI信号差异具有非常显著性意义 (P <0 0 0 1) ,T1WI信号接近 ,其病理学基础是扩大的腺泡。SBPA的时间 信号曲线为快速强化和快速消退的双期曲线 ,强化峰值时间为 (6 0± 10 )s ,平均强化速率为 (6 0 0± 5 0 ) /min ;CSB在 5min内呈持续强化的单一上升峰 ,强化峰值时间 >5min ,平均强化速率 (4 0± 5 ) /min。二者强化峰值时间和平均强化速率差异具有显著性意义 (P <0 0 1,P <0 0 0 1)。结论　CT诊断SBPA价值有限 ,无鉴别意义。T2 WI稍高信号背景上散布高信号小泡影是SBPA的特征性MRI征象 ,有定性诊断价值。动态增强MRI有助于SBPA与CSB的鉴别。     

MRI对肝细胞腺瘤的诊断价值

肝细胞腺瘤(HA)是一种临床上比较少见的肝脏良性肿瘤,本文报告经手术病理证实的4例肝细胞腺瘤(HA),并结合文献分析讨论如下。1材料与方法收集本院2005年12月~2006年3月经手术病理证实的肝细胞腺瘤(HA)4例,均为男性,年龄33~52岁,平均42.5岁。4例患者AFP(甲胎蛋白)、CEA(癌胚抗原)和CA19-9(糖链抗原)均无增高表现。使用Siemens Sonata 1.5T超导型磁共振扫描仪,采用体线圈。扫描序列:平扫横断位采用快速小角度激发成像序列,(FL2D)T1WI加脂肪抑制(FS)和单次激发半傅立叶采集快速自旋回波序列(HASTE)T2WI;冠状位采用真正稳态下的快…     

Cirrhosis: CT and MR imaging evaluation

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, "pseudo-cirrhosis" due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.     

CT and MR imaging characteristics of infantile hepatic hemangioendothelioma

Aim

This study aims to analyze computed tomography (CT) and magnetic resonance (MR) imaging features of infantile hepatic hemangioendotheliomas before and after treatment.

Materials and methods

CT and MR examinations of seven infants with biopsy proven hepatic hemangioendotheliomas were retrospectively analyzed. The distribution, number, size, imaging appearance, enhancement pattern and post-treatment changes of the tumors were evaluated.

Results

A total of 153 hepatic hemangioendotheliomas were detected on CT (111) and MR (42) imaging. In six infants, 109/111 (98.2%) tumors were hypodense and 2/111 (1.8%) lesions contained calcification on unenhanced CT. On MR imaging, all 42 lesions in one infant were heterogeneously T1-hypointense and T2-hyperintense compared to the normal liver parenchyma. Contrast-enhanced CT and MRI showed peripheral rim (51.6%), uniform (48.4%), fibrillary (33.3%), and nodular (28.8%) contrast enhancement in the hepatic arterial phase. Homogeneous (100%), rim (98.2%) and mixed enhancement patterns were noted in tumors <1.0 cm, >2.0 cm and 1.0-2.0 cm in diameter respectively in the hepatic arterial phase. In three patients who underwent steroid therapy, follow-up CT examination demonstrated tumor size reduction and increased intra-tumoral calcification in two patients.

Conclusion

Infantile hepatic hemangioendotheliomas show some typical imaging features and size-dependent pattern of contrast enhancement on CT and MR imaging, which allow accurate imaging diagnosis and post-treatment evaluation.     

肾嗜酸细胞腺瘤CT及MRI表现

目的：总结分析肾脏嗜酸细胞腺瘤的影像学表现,提高诊断水平。方法：回顾性分析经手术病理证实的10例肾脏嗜酸细胞腺瘤的临床及影像学资料,并与手术病理进行对比分析。结果：9例为单发肿瘤,1例并发肾透明细胞癌。肿瘤呈圆形或类圆形,直径1.5~5.4 cm,境界清晰,均位于肾皮质区,向肾外突出。CT平扫病灶多呈等密度;平扫T1WI病灶呈等信号或低信号,其中4例中央裂隙状疤痕呈更低信号;T2WI病灶呈等、高信号或低信号,肿瘤内混杂稍高信号,中央疤痕呈裂隙状高信号。动态增强扫描7例明显均匀强化;2例不均匀强化,但肿瘤实质部分强化均匀,中央疤痕大部分无强化,少部分延迟强化;1例皮髓质期扫描呈＂轮辐状＂强化。结论：肾脏嗜酸细胞腺瘤是一种良性肿瘤,位于肾皮质区,可向肾外突出,边界清楚。平扫肿瘤呈等密度或信号,增强扫描肿瘤均匀强化、中央出现星状疤痕以及肿瘤＂轮辐状＂强化内其特征性影像表现。     

Primary hepatic angiosarcoma: findings at CT and MR imaging

PURPOSE: To evaluate and describe cross-sectional imaging findings in patients with pathologically confirmed primary hepatic angiosarcoma. MATERIALS AND METHODS: Findings from imaging examinations in 13 patients with pathologically confirmed primary hepatic angiosarcoma were retrospectively reviewed (computed tomographic [CT] images obtained in 10 patients and magnetic resonance [MR] images obtained in five patients were available for review). Two gastrointestinal radiologists evaluated lesion number, size, attenuation and signal intensity characteristics, and the pattern and degree of contrast material enhancement. Medical records were reviewed for clinical features associated with angiosarcoma. RESULTS: Angiosarcoma appeared as multiple nodules (n = 6), as dominant masses (n = 6), or as a diffusely infiltrating lesion (n = 1). Multiple nodules were hypoattenuating at unenhanced and contrast material--enhanced CT (six of six patients). When dominant masses were encountered at MR imaging, T2-weighted MR imaging demonstrated heterogeneous internal architecture (four of four patients) similar to that of hepatocellular carcinoma. Multiphase contrast-enhanced CT and MR images showed dominant masses to have heterogeneous and progressive enhancement (three of three patients). Clinical features associated with angiosarcoma included splenic metastases (six of 13 patients), thrombocytopenia (seven of 13 patients), disseminated intravascular coagulation (four of 13 patients), and hemolytic anemia (three of 13 patients). CONCLUSION: Primary hepatic angiosarcoma exhibits a spectrum of appearances that reflect its varied pathologic features.     

CT and MR imaging of benign hepatic and biliary tumors.

Benign hepatic and biliary tumors can present a difficult diagnostic challenge. Spiral computed tomography (CT) and magnetic resonance (MR) imaging are useful in the detection and characterization of these tumors. Imaging characteristics of lesions such as hepatic cyst, hemangioma, focal nodular hyperplasia (FNH), and hepatic adenoma are well known. Hepatic cysts demonstrate water attenuation at CT, are isointense relative to water at MR imaging, and do not enhance after intravenous administration of contrast material. Hemangiomas demonstrate characteristic nodular peripheral enhancement on early-phase images with subsequent fill-in centrally at both modalities. FNH classically demonstrates intense early enhancement with washout on delayed images. Although hepatic adenoma can also demonstrate intense early enhancement, it has a tendency to bleed and thus often appears more heterogeneous than FNH due to hemorrhage. Benign hepatic tumors that are less well described in the imaging literature include hepatic lipoma or angiomyolipoma, infantile hemangioendothelioma, and mesenchymal hamartoma. Hepatic lipoma has fat attenuation at CT, is isointense relative to fat at MR imaging, and does not enhance after intravenous administration of contrast material. Hepatic angiomyolipomas contain a variable amount of soft tissue in addition to fat and may therefore demonstrate enhancement at both modalities. The CT and MR imaging appearances of infantile hemangioma are similar to those of adult hemangioma. Infantile hemangioendothelioma occurs in infants under 6 months of age and is typically a larger lesion. Mesenchymal hamartoma also occurs in children, and its imaging appearance depends on the presence of stromal elements and the protein content of the cyst fluid. Familiarity with these imaging features can help distinguish particular disease entities.     

CT diagnosis of hepatic adenoma

Only few publication have so far been known on case histories in the context of CT-findings of hepatic adenoma (HA). An analysis was, therefore, made of the findings of ten patients with HA. Precontrast and postcontrast scans (dynamic CT), densitometric evaluations (gamma-fit) and "profile" determination were taken into consideration. Diagnostic relevance is attributed to two types of features (with and without tumour haemorrhage) as well as to complementary findings (capsule-like structure and fat-ring around the tumour, island-like areas).     

MR imaging of pituitary adenoma: CT, clinical, and surgical correlation

Twenty-five patients with suspected pituitary adenoma were evaluated prospectively with CT and MR. Nine patients underwent transsphenoidal surgery, and three of these showed a documented decrease in size of mass on bromocriptine therapy. CT was more sensitive than MR for detecting focal lesions (seven vs three) and sellar-floor erosion (12 vs six). MR was superior to CT in identifying infundibular abnormalities (seven vs six), focal abnormalities of the diaphragma sellae (10 vs seven), cavernous sinus invasion (four vs two), and optic chiasm compression (six vs zero). Thus, MR may be the procedure of choice for optimal identification and localization of macroadenoma. For patients with suspected microadenoma, however, this preliminary series indicates that CT remains the radiographic procedure of choice.     

Vagal neuropathy: evaluation with CT and MR imaging

The vagus nerve, as a result of its protracted course from the brain stem to the abdomen, can present a difficult imaging problem when it is compromised by a clinically occult lesion. The clinical and radiologic records of 48 patients with suspected vagus nerve dysfunction were reviewed to derive an efficient and effective approach to imaging this patient population. An imaging algorithm is proposed in which vagal neuropathies are divided both clinically and radiologically into proximal and distal categories. Proximal vagal lesions are part of a cranial neuropathy complex and have associated oropharyngeal signs and symptoms (e.g., abnormal gag reflex, uvular deviation). Distal vagal lesions occur as an isolated paralysis of the vagus nerve with no symptoms or signs referable to the oropharynx. Either computed tomography (CT) or magnetic resonance imaging can be used to diagnose proximal or distal lesions. However, CT will be insensitive in the detection of the more cephalic proximal lesions, especially those in the brain stem, basal cisterns, and skull base.     

Sphenochoanal polyps: evaluation with CT and MR imaging

A sphenochoanal polyp is a solitary mass of low attenuation on computed tomographic (CT) scans that arises from the sphenoid sinus and extends through the sphenoid ostium, across the sphenoethmoid recess, and into the choana (the boundary between the nasal cavity and nasopharynx). More often, however, a choanal polyp is an antrochoanal polyp, which arises from the maxillary antrum, protrudes through the middle meatus, extends into the nasal cavity, and continues back to the choana. Contiguous axial or coronal magnetic resonance and CT images help clearly differentiate the rare sphenochoanal polyp from the more common antrochoanal polyp. The sinus of origin is important to identify, as the surgical approach depends on the target sinus.     

Detection of focal hepatic masses: prospective evaluation with CT, delayed CT, CT during arterial portography, and MR imaging

The sensitivities of contrast medium-enhanced computed tomography (CT), delayed CT (DCT), CT during arterial portography (CTAP), and magnetic resonance (MR) imaging for detecting focal liver lesions were prospectively evaluated in eight patients who subsequently underwent hepatic lobectomy or transplantation. Pathologic evaluation of the resected liver specimens demonstrated 37 lesions. The sensitivities were 81% (30 of 37 lesions) for CTAP, 57% (21 of 37 lesions) for MR imaging, 52% (12 of 23 lesions) for DCT, and 38% (14 of 37 lesions) for contrast-enhanced CT. The difference between the sensitivity of CTAP and the sensitivities of the other imaging tests was statistically significant (P less than .004). Of the lesions smaller than 1 cm in diameter, CTAP depicted 61% (11 of 18 lesions), MR imaging 17% (three of 18 lesions), CT 0% (zero of 18 lesions), and DCT 0% (zero of nine lesions). It is concluded that for preoperative detection of focal hepatic masses, CTAP is the most accurate technique available to most radiologists. Patients with primary or secondary hepatic neoplasms who are being considered for hepatic resection should undergo CTAP as part of their preoperative examination.     

Pleomorphic adenoma of salivary glands: common and uncommon CT and MR imaging features

Pleomorphic adenoma (PA) is the most common salivary gland tumor and is characterized by cytomorphological and architectural diversity. On CT and MR images, PAs are shown as well-defined lesions occasionally accompanied by characteristic lobulated contours. On T2-weighted images, typical PAs show marked hyperintensity, which reflects the abundant myxochondroid stroma, with a hypointense rim indicating the fibrous capsule. However, intratumoral signal intensity varies according to the cellular density, proportion of epithelial and stromal components, and type of stromal components. In addition, a variety of secondary histological changes, including fibrosis, lipometaplasia, ossification, cystic degeneration, and infarction, occur rarely in PAs; therefore, they are associated with difficulty in differential diagnosis from other salivary gland tumors. This review article describes the common and uncommon CT and MR imaging features of PA of the salivary glands.     

CT and MR imaging in the evaluation of retroperitoneal fibrosis

We have performed CT and MR on five patients with biopsy proven retroperitoneal fibrosis (RPF). Magnetic resonance (MR) accurately displayed a retroperitoneal mass of low signal intensity on T1-weighted scans and of heterogeneous medium signal intensity on T2-weighted scans. The coronal MR views demonstrated a retroperitoneal mass: the shape, signal intensity, and effects on the ureters and major vessels appear characteristic of RPF.     

肿瘤软脑膜-蛛网膜转移的CT、MRI诊断

目的研究肿瘤软脑膜蛛网膜转移的ＣＴ、ＭＲＩ表现,并探讨两种检查方法对该病的诊断价值。方法回顾分析２１例肿瘤软脑膜蛛网膜转移的临床及影像学资料。病变经ＣＴ检查１６例,ＭＲＩ检查７例,其中经两种方法检查者２例。结果全部病例软脑膜蛛网膜下腔均出现病理性强化,其中１０例呈弥漫性,８例呈结节性,３例呈弥漫与结节混合性。弥漫性强化沿脑和脑干表面分布,并延伸入脑沟、脑池;结节性强化病灶数目１个或多个不等,直径０．２～３．０ｃｍ。病变见于基底脑池及相邻蛛网膜下腔者共１８例。伴室管膜结节性强化４例,天幕增厚强化１０例,脑积水１３例,合并脑内转移９例。结论增强ＣＴ和ＭＲＩ对病变的诊断具有重要临床意义,且ＭＲＩ优于ＣＴ。但两者在定性诊断上均有局限性。正确诊断有赖于结合临床资料和影像征象的综合分析