Rathke囊肿囊内结节的MRI表现及诊断价值

目的：研究Rathke囊肿的囊内结节MRI表现特点及意义。方法：回顾性分析27例经手术病理证实的Rathke囊肿的MRI表现,观察囊内结节的发生率、大小、信号特点及有无强化。其中男11例,女16例,平均年龄33.4岁。所有患者均行MRI平扫及增强扫描。结果：10例Rathke囊肿内出现结节,T1WI表现为高、等或稍低信号,T2WI表现为低信号。结节大小为0.3-1.1 cm,平均0.6 cm。增强扫描囊内结节无强化。结论：鞍区囊性占位内出现囊内结节,显示特征性信号并且无强化,有助于Rathke囊肿的诊断。     

Rathke cleft cysts: correlation of enhanced MR and surgical findings.

PURPOSETo describe the gadolinium-enhanced MR findings of Rathke cleft cyst correlate them with the surgical findings, and define those preoperative findings that differentiate this lesion from other sellar and juxtasellar tumors.METHODSWe studied 18 patients who were diagnosed as having Rathke cleft cyst pathologically. These patients were imaged with T1- and T2-weighted coronal and sagittal spin-echo sequences. Fifteen of these patients received gadopentetate dimeglumine.RESULTSIn eight patients, the cyst showed low intensity on T1-weighted images and high intensity on T2-weighted images. At surgery, the cyst fluid was cerebrospinal fluid-like or light brown in five patients, motor oil-like in one patient, and milky in two patients. In 10 patients, cysts showed isointensity to high intensity on T1-weighted images and had various intensity on T2-weighted images. All 10 contained milky fluid. In three patients the intensity of fluid was heterogeneous. A waxy nodule was found in two patients. The position of the normal pituitary gland confirmed by surgery in all cases coincided with enhancement on MR imaging. The variable position of the normal pituitary gland was clearly identified in the sagittal images. The cyst walls showed no enhancement by gadopentetate dimeglumine.CONCLUSIONSBecause Rathke cleft cysts show variable intensities on MR, the diagnosis is often difficult when based on MR signal intensity values alone. MR imaging with gadopentetate dimeglumine does assist in the diagnosis of Rathke cleft cysts. Diagnostic clues include the lack of cyst wall enhancement and displacement of the normal pituitary gland.     

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.     

Rathke cleft cyst: MR and biomedical analysis of cyst content

PURPOSE: At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal. METHOD: We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro. RESULTS: All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images. CONCLUSION: The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.     

Uncommon presentation of a giant biliary cystadenoma: correlation between MRI and pathologic findings.

An uncommon case of a giant mucinous biliary cystadenoma (BCA) of the liver is described. On T2-weighted and STIR images, a large hyperintense cystic mass revealed some septations and multiple intracystic masses of similar size and shape and uniform signal intensity, which was isointense to liver parenchyma. On T1-weighted images, intracystic bodies were obscured and the cyst was hyperintense. The magnetic resonance (MR) appearance of intracystic fluid and structures was not due to mucinous or proteinous or hyperproteinous material, but corresponded to clots floating within hemorrhagic fluid.     

MR appearance and cyst content of Rathke cleft cysts

The magnetic resonance signal intensity and cyst content were analyzed in 2 new and 17 previously reported cases of Rathke cleft cyst. Lesions displaying hypointensity on T1-weighted images (T1WI) and hyperintensity on T2-weighted images (T2WI) contained CSF-like fluid. Cases showing hyperintensity on T1WI and isointensity on T2WI frequently contained mucoid material. Hyperintensity on both T1WI and T2WI suggests the presence of blood. A small area of hypo- or isointensity indicates thickening of the cyst wall or collection of cellular debris.     

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.     

Biliary cystadenoma with mesenchymal stroma of the liver: Correlation between unusual MR appearance and pathologic findings

We reported a case of the biliary cystadenoma of the liver. The cystic mass had labulation and septation and showed marked hyperintensity on T1-weighted images and hypointensity on T2-weighted images; MR findings were very unusual for cystadenoma. The content of the cystic mass was jelly-like, thick mucinous fluid without intracystic hemorrhage. We concluded that these unusual signal intensities of the cyst were due to hyperproteinous mucinous fluid.     

Colloid Cysts of the Third Ventricle: Are MR Imaging Patterns Predictive of Difficulty with Percutaneous Treatment?

BACKGROUND AND PURPOSE: Colloid cysts of the third ventricle are rare benign brain tumors. The purpose of this study was to correlate their patterns on MR images with the probability of success of percutaneous treatment. METHODS: Nineteen patients underwent endoscopic treatment for colloid cysts of the third ventricle. The cases were divided into two groups based on difficulty of the aspiration procedure. We reviewed CT scans and MR images and divided cysts into groups based on their signal intensity on the MR images and their density on CT scans. Intensity and density were correlated with difficulty of aspiration during the endoscopic procedure. RESULTS: The aspiration procedure was difficult in 63% of the cases. Eighty-nine percent of hyperdense cysts on unenhanced axial CT scans were categorized as difficult, and 75% of hypodense cysts were categorized as easy. On T2-weighted MR sequences, 100% of low-signal cyst contents were difficult and nearly 63% of high-signal lesions were easy. There was a significant correlation between the T2-weighted sequences and the CT scans regarding the difficulty of the aspiration procedure. CONCLUSION: T2-weighted MR sequences are useful for predicting difficulty of aspiration during stereotactic or endoscopic procedures. A T2-weighted low-signal cyst is correlated with high-viscosity intracystic contents.     

MR imaging of müllerian mucinous borderline tumors arising from endometriotic cysts

This report describes MR findings of müllerian mucinous borderline tumors, pathologically proven to have arisen from endometriotic cysts, in three patients. They were unilocular or paucilocular masses with mural nodules. Cystic components showed hyperintensity on both T1- and T2-weighted images, simulating clear cell or endometrioid carcinomas arising from endometriotic cysts. Mural nodules showed prominent high signal intensity on T2-weighted images. Correlation with pathologic findings suggests that this hyperintensity reflects intraluminal mucinous material and stromal edema.     

Characteristics of Rathke's cleft cyst in MR imaging.

PURPOSE: Symptoms, macroscopic appearances and microscopic findings of Rathke's cleft cysts with magnetic resonance (MR) imaging. Patients and METHODS: We analyzed the data from 31 patients with pathologically confirmed Rathke's cleft cysts. MR appearances were evaluated on T1WI, T2WI and contrast T1WI. Symptoms, macroscopic appearances and pathological findings were obtained from available medical records. We analyzed the images according to the following criteria: 1. findings on the location and shape of the lesions and form of the lesional wall; 2. the relationship between the maximum diameter of the lesions and symptoms; 3. the relationship between MR and macroscopic appearance; 4. the sites of adjacent contrast enhancement. RESULTS: The lesions were located mostly in both the intrasellar and suprasellar regions for a total of 87%. All lesions revealed either an oval or dumbbell shape with a smooth lesional wall. When correlated with physical symptoms, asymptomatic cases were associated with smaller lesions, while visual disturbances and dizziness were associated with relatively larger lesions. MR lesion signal intensity was related to the content of macroscopic appearance to some degree: the selected lesions showed shortening of T1 and T2 relaxation times in relation to the increase in protein concentration. This should have been macroscopically reflected in the color and turbidity of the liquid within the cyst. Adjacent contrast enhancement around the lesion was found at various sites, but anterior enhancement was most frequent. Circumferential enhancement was revealed to be derived from inflammatory changes. CONCLUSION: Rathke's cleft cyst exhibits a varied MR signal. It may be difficult to differentiate from craniopharyngioma from the intensity alone.     

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.     

Parapharyngeal second branchial cyst manifesting as cranial nerve palsies: MR findings

SUMMARY: We report the MR findings of parapharyngeal branchial cleft cyst manifesting as multiple, lower cranial nerve palsies in a 35-year-old woman. On MR images, a well-marginated cystic mass was detected in the right parapharyngeal space, with displacement of both the right internal carotid artery and the right internal jugular vein on the posterolateral side. The cyst contained a whitish fluid that was slightly hyperintense on T1-weighted images and slightly hypointense to CSF on T2-weighted images. No enhancement on contrast-enhanced T1-weighted images was present. The right side of the tongue showed high signal intensity on T2-weighted images, suggesting denervation.     

Complex and simple renal cysts: comparative evaluation with MR imaging

Magnetic resonance (MR) imaging was performed in two groups of patients to determine its usefulness in evaluating fluid-containing renal masses deemed complex with computed tomography (CT). Twenty-two patients in group 1 had indeterminate renal masses by CT, five of which were also indeterminate by ultrasound (US). The results in this group were compared with histologic findings. Group 2 consisted of 20 patients with simple renal cysts diagnosed according to rigid CT criteria. On MR imaging, 11 of the 23 masses in group 1 and 19 of the 20 in group 2 were diagnosed as benign cysts. Fluid within the cyst had long T1 and T2, resulting in a low signal intensity on T1-weighted images. In the 12 remaining lesions in group 1 and in one lesion in group 2, the fluid content was indeterminate and MR did not permit differentiation of cystic renal carcinoma from old hemorrhage or adenoma. When fluid within the cystic mass did not have the MR characteristics of simple fluid, MR was not helpful in characterizing the mass, but when the fluid intensity was similar to normal urine, the cyst was benign.     

Neurenteric cyst with alteration of signal intensity on follow-up MR images

SUMMARY: Intracranial neurenteric cysts are uncommon and usually have low intensity on T1-weighted MR images and high intensity on T2-weighted MR images. We report a case of a neurenteric cyst that was situated in front of the medulla oblongata and the size of which increased with alteration of MR signal from high to isointense compared with that of brain on T1-weighted images obtained 33 months after the initial MR images. We think that the signal change of the cyst was probably caused by a change of protein concentration.     

Magnetic resonance imaging signal characteristics in hydatid cysts

The MRI features of hydatid cysts were retrospectively studied in 12 patients to look for specific signal characteristics. Twelve patients in the series included eight with abdominal, two with abdominal-pelvic, one with a sacral and one with a lung hydatid cyst. The T1-, T2- and proton density (PD)-weighted images of spin-echo sequence were used for imaging. The signal characteristics of the hydatid parent cyst capsule and fluid, daughter cyst fluid, detached germinal membrane and surrounding soft tissue reaction were noted. Observations revealed that the capsule is best seen on T2- and PD-weighted images. The daughter cysts are best demonstrated on T1-weighted images, whereas the difference in the signal intensities of parent cyst and daughter cyst fluid is better demonstrated on T2-weighted and T1-weighted images, and the detached germinal membrane is best seen on T2- and PD-weighted images. The signal characteristics of hydatid cyst morphology can help distinguish it from other entities.     

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.     

Intracranial tuberculoma: comparison of MR with pathologic findings.

PURPOSETo compare the MR signal intensity patterns and enhancement pattern of intracranial tuberculomas with their histopathologic features.METHODSMR images of six patients with surgically proved intracranial tuberculoma were reviewed retrospectively and were compared with histologic findings of the resected specimen. Detailed histologic examination was performed to look for the extent and characteristics of caseation necrosis, fibrosis, and inflammatory cellular infiltrates at each area of different signal intensities and at the enhancing areas on MR. Signal intensities for T1- and T2-weighted images were compared with normal gray matter.RESULTSOn T1-weighted images, the granulomas showed a slightly hyperintense rim surrounded by a complete or partial rim of slight hypointensity and central isointensity or mixed isointensity and hyperintensity in five patients and homogeneous isointensity in one patient. Histologically, the zone of central isointensity or mixed intensity corresponded to caseation necrosis plus adjacent cellular infiltrates. The hyperintense and hypointense rims corresponded to the layers of collagenous fiber and the layers of the inflammatory cellular infiltrates, respectively. On T2-weighted images, the entire portion of the granuloma showed slightly heterogeneous isointensity or hypointensity with small markedly hypointense foci in five patients, and a hyperintense center surrounded by a hypointense rim in one patient. Histologic layers were not discriminated on T2-weighted images. On postcontrast T1-weighted images, there were single or multiple conglomerate ring enhancements within a tuberculoma in all six patients, corresponding to the layers of both collagenous and inflammatory cells.CONCLUSIONCombination of the described signal intensity patterns and conglomerate ringlike enhancing appearance of the lesion is characteristic of tuberculoma, and may play an important role in differentiating intracranial tuberculomas from other ring-enhancing brain lesions.     

Variable MR findings in ovarian functional hemorrhagic cysts

PURPOSE: To describe the magnetic resonance (MR) findings in ovarian functional hemorrhagic cysts (FHC). MATERIALS AND METHODS: A total of 21 patients with 22 FHC, proven by follow-up ultrasound (US) in 11 women and surgery in 10 women, had US and MR examinations within 24 hours. The study was limited to cysts with obvious an echogenic pattern. All patients had T2-weighted fast spin echo (FSE), T1-weighted spin echo (SE), and T1-weighted SE fat-suppressed sequences. RESULTS: Four cysts (18%) were hypointense on T1-weighted-images without and with fat suppression, and hyperintense on T2-weighted-images. Five cysts (23%) were hypointense on T1-weighted images without and with fat suppression but heterogenous on T2-weighted images. Five cysts (23%) were hypointense on T1-weighted images but showed intermediate signal intensity on T1-weighted fat suppression images and heterogenous signal intensity on T2-weighted images. Two cysts (9%) were entirely intermediate on T1-weighted images. Five cysts (23%) displayed high signal intensity occupying less than 30% of the cystic content on T1-weighted images and one cyst (5%) displayed high signal intensity occupying more than 30% of the cystic content. CONCLUSION: Despite an obvious echogenic pattern on US, 64% of FHC were hypointense on T1-weighted images and 18% were also hyperintense on T2-weighted images. Only 36% demonstrated intermediate or high signal intensity on T1-weighted images.     

Ovarian carcinoma in patients with endometriosis: MR imaging findings

OBJECTIVE: Various types of malignancy can develop in patients with endometriosis. Enhancing mural nodules have been reported as an imaging characteristic of malignant transformations. We evaluated contrast-enhanced MR imaging to determine the optimum sequence to reveal mural nodules and other characteristics of malignant transformations. MATERIALS AND METHODS: We examined 10 patients with pathologically proven ovarian adenocarcinoma in endometriosis and 10 patients (the control group) with ovarian endometrioma suggestive of malignant transformation on the basis of sonographic findings. We analyzed the size and nature of the endometriomas in each patient. We compared four types of contrast-enhanced MR imaging to determine which sequence best revealed mural nodules. RESULTS: In the malignant and control groups, 80% of the cysts with findings suggestive of malignant transformation showed unilateral disease or larger endometrial cysts on the suggestive side than on the contralateral side. High signal intensity on T1-weighted images and low signal intensity on T2-weighted images relative to the myometrium were observed only in two of 10 malignant endometrial cysts and in all control cysts. All malignant endometriomas had small mural nodules with low signal intensity on T1-weighted contrast-enhanced images. Only three benign endometriomas had mural nodules and none of them enhanced. The enhancement of mural nodules was easily seen on dynamic subtraction imaging. CONCLUSION: On the basis of our findings, endometrial cysts with malignant transformation rarely show low signal intensity on T2-weighted images and usually have enhancing mural nodules. Because the enhancement of mural nodules is often difficult to evaluate on conventional T1-weighted images, dynamic subtraction imaging can be valuable.