Rathke囊肿:CT、MRI表现与病理对照研究

目的：探讨Rathke囊肿的影像学表现与病理组织学之间的关系。材料和方法：病理证实的Rathke囊肿20例，男12例，女8例。年龄11—70岁，平均44岁。18例行CT检查，其中7例增强；12例行MRI检查，其中7例增强；20例中CT和MRI检查均进行有10例。分析所有CT、MRI片，并与手术病理对照。结果：10例Rathke囊肿位于鞍内，9例位于鞍内伴鞍上延伸，1例位于鞍上。Rathke囊肿因其囊液成分不同而有不同的影像学表现。少数伴出血。一般无强化，少数可见囊壁的强化。结论：Rathke囊肿影像学表现多样，CT和MRI有一定的价值，确诊需结合病理分析。     

MR appearance of Rathke's cleft cysts

Summary Two of three patients who proved to have symptomatic Rathke's cleft cysts presented with visual field deficit and all with diabetes insipidus. CT showed intra- and suprasellar cystic low density lesions with ring enhancement. MR showed intra-and suprasellar masses. On the T1-weighted images two of the three had hyperintense portions similar to fat and the other a hyperintense portion similar to white matter within the cysts. These portions were isointense to brain on the T2-weighted images in all cases. This characteristic intensity on MR images provides differentiation from cystic pituitary adenomas and cystic craniopharyngiomas, and leads to correct diagnosis of Rathke's cleft cyst.     

Arachnoid cysts: computed tomography findings

Described are 26 cases of arachnoid cysts. Of these cysts, 54% were in the sylvian cistern, three (1.2%) were in the suprasellar cistern, and the rest were over the cerebral sulci. There were symptoms of seizures at presentation in 30.8%, and in 23% there were symptoms of hydrocephalus and compression of the brain. A total of 61.5% presented with mental retardation and/or cerebral palsy. Trauma and infection accounted for 35% of these cysts. Associated porencephaly were present in five cases. There was a male preponderance. Left-sided lesions accounted for 61.5% of the lesions. The radiologic appearances, especially of suprasellar cysts, and the differential diagnoses of these lesions are discussed. Their recognition and the role of surgery are stressed.     

Rathke cleft cysts: CT, MR imaging, and pathologic features

The authors retrospectively reviewed the clinical, computed tomography (CT), and magnetic resonance (MR) imaging findings in seven patients with pathologically proved Rathke cleft cysts. All the cysts were located in the anterior sella turcica or the anterior suprasellar cistern. Five cysts had both intra- and suprasellar components, one was entirely intrasellar, and the other was predominantly suprasellar in location. The size of the cysts ranged from 8 to 20 mm. CT scans demonstrated low-density homogeneous lesions in four cases. On MR images of three of these four cases, the cysts had the same intensity as cerebrospinal fluid on T1- and T2-weighted images, while in the fourth case, the cyst was hyperintense on the T1-weighted images. In the remaining three cases, CT showed slight hyperdensity relative to brain parenchyma, suggestive of contrast enhancement. MR showed signal heterogeneity of these lesions with focal components of diminished signal intensity of T2-weighted images. These same foci appeared iso- to slightly hyperintense on T1-weighted images.     

Suprasellar arachnoid cysts: 1. CT recognition

Suprasellar arachnoid cysts are basal midline masses that represent a rare but surgically remediable cause of hydrocephalus and neurologic deficits. These cysts represent a diagnostic challenge and often go unrecognized for many years. The authors review the computed tomographic (CT) findings in seven patients with documented suprasellar arachnoid cysts and define previously undescribed diagnostic criteria. These cysts usually can be differentiated from cystic midline neoplasms by their CT density, homogeneity, and location as well as by their lack of fat, lack of calcification, and absence of contrast enhancement. Accurate distinction from marked third-ventricular enlargement secondary to obstructive hydrocephalus and from third-ventricular ependymal cysts can be made on the basis of basal cisternal expansion, distinctive mass effect and displacement, the characteristic shape and contour of the apparent "third ventricle," and the appearance of structures at the foramen of Monro. Although metrizamide CT ventriculography and cisternography allow confirmation of the diagnosis and evaluation of cerebrospinal fluid dynamics, these definitive studies will not be obtained unless the cysts are first suspected by their conventional CT appearance.     

Imaging of giant pituitary adenomas

We present five proven giant pituitary adenomas studied by CT and MRI, and review the clinical and imaging findings. Our aim was to examine the radiologic appearances and to search for criteria useful in distinguishing these tumors from other sellar and suprasellar tumours, mainly craniopharyngioma. The main differences from small adenomas were high prevalence of macrocysts, a more invasive behaviour and a clinical picture dominated by mass effect rather than endocrine disturbance. Factors supporting the diagnosis of pituitary adenoma in a giant intra- and suprasellar mass include: infrasellar extension, absence of calcification and presence of low-signal cysts on T1-weighted images. Received: 13 October 1997 Accepted: 25 February 1998     

Rathke囊肿的CT和MRI诊断

目的:分析Rathke囊肿之CT及MRI表现.材料和方法:回顾性分析7例(男3例,女4例,平均年龄32.4岁)经手术病理证实的Rathke囊肿的CT及MRI表现.结果:7例Rathke囊肿中,单纯位于鞍内者3例,直径均小于1.2cm;鞍内鞍上者4例,直径均大于1.2cm.CT及MRI表现根据囊液成分的不同变化多样,增强扫描一般无增强,囊壁极少钙化.结论:垂体Rathke囊肿术前较难明确诊断,仔细分析其CT及MRI表现,有助于提高本病的正确诊断率.     

Unique MR spectroscopic finding in colloid-like cyst

Cysts morphologically identical to colloid cysts are rarely reported to be located in areas outside the third ventricle. We report the magnetic resonance (MR) imaging and spectroscopic findings in three patients with colloid like cyst located in the ponto-medullary, pre-pontine cistern and suprasellar region. The MR imaging and spectroscopy performed on a 1.5-tesla scanner in three female patients revealed T1 hyperintense mass lesions. A large dominant metabolite peak at 2.0-ppm chemical shift, simulating N-acetylaspartate (NAA) of normal neuronal tissue was detected within the lesion.This peak is probably due to the presence of glycoproteins secreted by the ciliated columnar epithelium lining these cysts. MR spectroscopy of colloid cyst has not been described in the literature and hence the findings in this study will help in the diagnosis of this cystic lesion especially when located at unusual location. The signal characteristics of these cysts in various sequences including diffusion weighted imaging (DWI) and susceptibility weighted imaging (SWI) are also discussed.     

Computed tomography in intra- and suprasellar epithelial cysts (symptomatic Rathke cleft cysts)

The computed tomographic (CT) and pathologic findings in three cases of intra- and suprasellar epithelial cysts (symptomatic Rathke cleft cysts) are described. Literature review revealed that the characteristic CT finding is an intrasellar and/or suprasellar low-density mass that may or may not be enhanced. The enhancement is ringlike or capsular in nature. Whether the cyst wall is enhanced or not seems to be dependent on the histologic features. It is suggested that the enhancement may be caused by an inflammatory process, either septic or aseptic, or squamous metaplasia in the wall, which is possibly induced by degeneration or infection of the cyst contents. Without these additional pathologic processes, the Rathke cleft cyst, a simple retention cyst, may exhibit no contrast enhancement.     

Giant cystic craniopharyngiomas

Summary Three cases of giant cystic craniopharyngiomas with large areas of extension beyond the suprasellar area are presented. The magnetic resonance (MR) appearance in one case is described. These giant tumors had large, multilobulated cysts that comprised the bulk of the tumors. In one case, there was an unusual extension of the large tumor cyst into the lateral ventricle. In two cases, the tumors extended to the level of the foramen magnum. On CT, the cyst contents of these two tumors were hyperdense and became hypodense postoperatively. All three tumors harbored calcifications in the form of clumps in the suprasellar region and rim calcifications around the cysts. None of the tumors exhibited contrast enhancement. A literature review of the radiographic features of craniopharyngiomas is discussed.     

Imaging of large Rathke's cleft cysts by CT and MRI: report of two cases

Two patients with large Rathke's cleft cysts in the sella turcica and suprasellar region presented with visual impairment and hypopituitarism. The entirely different CT and MRI appearances of the two cysts were thought to depend principally on the protein content of the cyst fluid.     

CT of intrasellar colloid cyst

Colloid cysts are congenital lesions considered to be derived from the primitive neuroepithelium and are most frequently located in the anterior third ventricle. In this paper a case of colloid cyst with a intra/suprasellar location is presented. Computed tomographic characteristics of this lesion were strongly consistent with the classic features of colloid cysts, particularly when interpreted retrospectively after surgical and histopathological data became available. The unusual occurrence of a colloid cyst in this location supports the theory that epithelial cysts related to sella turcica are derived not solely from Rathke cleft but also from neuroepithelium.     

MR differentiation of adamantinous and squamous-papillary craniopharyngiomas.

PURPOSETo determine MR criteria for differentiating adamantinous from squamous-papillary craniopharyngiomas.METHODSThe MR imaging features of 42 histologically proved craniopharyngiomas (25 adamantinous, 15 squamous-papillary, and two mixed subtypes) were examined with multiplanar T2-weighted and noncontrast and contrast-enhanced T1-weighted imaging. Differences in the mR features of both subtypes were evaluated retrospectively.RESULTSThe adamantinous craniopharyngioma is a mixed solid-cystic or mainly cystic lobulated suprasellar or intrasellar/suprasellar tumor occurring in children and adults, typically with large nonenhancing hyperintense cysts on T1-weighted images. The squamous-papillary craniopharyngioma is a predominantly solid or mixed solid-cystic suprasellar tumor occurring in adults, appearing as a hypointense cyst on noncontrast T1-weighted images. Calcifications and recurrent tumors are more often observed in adamantinous tumors but can be seen in squamous-papillary tumors as well. Statistically significant parameters useful for differentiating the two tumor subtypes are the encasement of vessels, the lobulated shape, and the presence of hyperintense cysts in adamantinous tumors, and the round shape, the presence of hypointense cysts, and the predominantly solid appearance in squamous-papillary tumors.CONCLUSIONCraniopharyngiomas can be divided into two clinically, histologically different subtypes, which suggests a different pathogenesis of these two types of tumor.     

Computed tomography of arachnoid cysts.

The typical CT appearance of intracranial arachnoid cysts may obviate additional neuroradiological procedures. Ventriculography using water-soluble contrast media may differentiate a suprasellar arachnoid cyst from a dilated third ventricle. Twelve cases are presented.     

鞍区胶质瘤的CT和MRI诊断

目的分析鞍区胶质瘤的CT和MRI特点及临床发病特征。资料与方法经手术病理证实的鞍区胶质瘤8例,其中7例位于鞍上,1例位于鞍内。3例行CT检查,5例行MRI检查。结果鞍上胶质瘤体积较大,呈不规则分叶状,边界光滑锐利,基本没有瘤周水肿,瘤内偏上方多发囊变,无明显钙化及出血,少数可沿视觉通路生长,CT平扫稍低或等密度,MRI检查T1WI呈稍低、低信号,T2WI高信号,CT及MR增强扫描,肿瘤实性部分可见显著强化。此外,临床上这些患者就诊时多有眼部症状．而均无下丘脑及垂体内分泌异常症状。鞍内胶质瘤位置偏后,瘤周无水肿,瘤内可有多发微囊变,无明显钙化及出血。结论鞍上胶质瘤有比较典型的CT和MRI特点,结合患者临床发病特点,有助于提高其术前诊断率;鞍内胶质瘤易误诊,对有多发微囊变的位置偏后的鞍内肿瘤,应考虑到本病可能。     

Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland.     

Neuroepithelial (colloid) cysts. Pathogenesis and unusual features.

A brief history of the theories of pathogenesis of the origin of neuroepithelial cysts is presented. An origin more diffuse than the paraphysis seems most likely in our opinion, and we attempt to substantiate this theory with several of the cases from our series. One posterior third ventricular neuroepithelial cyst and one in the fourth ventricle are demonstrated roentgenographically. Also included in our series are a case showing suprasellar calcification on plain skull roentgenograms, not previously reported in neuroepithelial cysts, and a case with a cyst measuring 9 cm, the largest neuroepithelial cyst yet reported.     

Suprasellar paraganglioma: a case report and review of the literature

Paragangliomas arising in the suprasellar region are extremely rare. We report a case of suprasellar paraganglioma in a 47-year-old man who presented with amnesia and impaired visual acuity without any endocrine dysfunction. Magnetic resonance imaging (MRI) showed a large enhancing tumour in the suprasellar area. Following subtotal surgical excision, the diagnosis of paraganglioma was confirmed by pathology. In this case report we describe the MRI pattern of suprasellar paraganglioma and review the literature of this uncommon lesion.     

Differentiation of suprasellar nonneoplastic cysts from cystic neoplasms by Gd-DTPA MRI.

Magnetic resonance imaging in 9 cases of surgically confirmed nonneoplastic intra- and/or suprasellar cysts was analyzed and compared with that from 17 cases of craniopharyngioma and 12 of cystic pituitary adenoma. Signal intensity did not help in distinguishing nonneoplastic cysts from cystic neoplasms. No postcontrast (Gd-DTPA) cyst wall enhancement was observed among the nonneoplastic cysts, although all 6 craniopharyngiomas and 12 cystic pituitary adenomas that underwent postcontrast study did enhance. Three nonneoplastic cysts were surrounded by the pituitary gland, thus mimicking wall enhancement in the postcontrast studies. Rapid enhancement in the early postcontrast-administration phase (dynamic studies) helped avoid confusion between the normal pituitary tissue and cyst wall enhancement. Magnetic resonance studies with contrast enhancement play an essential role in differentiating nonneoplastic cysts from cystic neoplasms in the sella region.     

Suprasellar arachnoid cysts: 2. Evaluation of CSF dynamics

Suprasellar arachnoid cysts are an infrequent but surgically remediable cause of hydrocephalus and neurologic deficits. The optimal method of treatment varies according to whether the cyst communicates with the subarachnoid space; the presence or absence of associated hydrocephalus; and the exact site(s) and severity of intraventricular and extraventricular cerebrospinal fluid (CSF) obstruction. Eight patients with suprasellar arachnoid cysts are described to emphasize the importance of pretherapeutic investigation of CSF dynamics. The variability of the ventriculocisternal-cyst CSF dynamics and the value of metrizamide computed tomographic cisternography and ventriculography in investigation of the CSF pathways are stressed. A diagnostic approach to the evaluation of the CSF dynamics is outlined, based on whether hydrocephalic or compressive symptoms predominate.