Colloid cyst of the third ventricle: sometimes more conspicuous on CT than MR.

We present two cases of surgically proved colloid cysts that were more apparent on CT scans than on MR images. These cysts, while hyperdense on CT scans, were nearly isointense with brain on multiple MR sequences. This relative lack of visibility represents a potential pitfall when imaging a patient with headache.     

Colloid cysts of the third ventricle: MR findings

Magnetic resonance was performed in five patients with obstructive hydrocephalus due to surgically proven colloid cyst of the third ventricle. On T1-weighted images two lesions were homogeneously hyperintense and another homogeneously isointense with the surrounding brain parenchyma. On T2-weighted images these three lesions were strongly hypointense except for a hyperintense rim at the periphery. At surgery in these patients the cyst was thin walled and filled with viscous colloidal material. In two patients the content of the lesion was composed of two layers. The outer layer was hyperintense and the inner layer hypointense in one patient. In the other patient the periphery of the lesion was isointense with central hypointensity. On T2-weighted images the content of both lesions was hyperintense at the periphery with central hypointensity. In these last two patients at surgery the cyst was thin walled too. However, two clearly different components could be found in the cyst content: an outer component composed of amorphous material and cellular debris and an inner component consisting of viscous material.     

Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis

Eight patients with colloid cysts of the third ventricle were examined with CT and MR. In six, surgical resection was performed and the material was subjected to histologic evaluation; the concentrations of trace elements were determined by particle-induced X-ray emission. Stereotaxic aspiration was performed in two. The investigation showed that colloid cysts are often iso- or hypodense relative to brain on CT (5/8), but sometimes have a center of increased density. Increased density did not correlate with increased concentration of calcium or other metals but did not correlate with high cholesterol content. Colloid cysts appear more heterogeneous on MR (6/8) than on CT (3/8), despite a homogeneous appearance at histology. High signal on short TR/TE sequences is correlated with a high cholesterol content. A marked shortening of the T2 relaxation time is often noticed in the central part of the cyst. Analysis of trace elements showed that this phenomenon is not related to the presence of metals with paramagnetic effects. Our analysis of the contents of colloid cysts does not support the theory that differing metallic concentrations are responsible for differences in MR signal intensity or CT density. We did find that increased CT density and high MR signal correlated with high cholesterol content.     

Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis

Eight patients with colloid cysts of the third ventricle were examined with CT and MR. In six, surgical resection was performed and the material was subjected to histologic evaluation; the concentrations of trace elements were determined by particle-induced X-ray emission. Stereotaxic aspiration was performed in two. The investigation showed that colloid cysts are often iso- or hypodense relative to brain on CT (5/8), but sometimes have a center of increased density. Increased density did not correlate with increased concentration of calcium or other metals but did correlate with high cholesterol content. Colloid cysts appear more heterogeneous on MR (6/8) than on CT (3/8), despite a homogeneous appearance at histology. High signal on short TR/TE sequences is correlated with a high cholesterol content. A marked shortening of the T2 relaxation time is often noticed in the central part of the cyst. Analysis of trace elements showed that this phenomenon is not related to the presence of metals with paramagnetic effects. Our analysis of the contents of colloid cysts does not support the theory that differing metallic concentrations are responsible for differences in MR signal intensity or CT density. We did find that increased CT density and high MR signal correlated with high cholesterol content.     

Hypodense colloid cyst of the third ventricle

The diagnosis of colloid cysts of the third ventricle using computed tomography (CT) rarely causes problems. The typical well-rounded, hyperdense mass in the anterior part of the third ventricle is usually well shown, along with the associated lateral ventricular dilatation. However, it is also well recognized that these cysts may be isodense, and this can on occasion lead to diagnostic difficulty. Rarely have hypodense colloid cysts been reported. We describe two patients in whom the low density of the tumors led, initially, to a failure to identify them on the CT scan. Although this is an atypical appearance, it is important to be aware of it, as colloid cysts which are surgically curable have a definite morbidity and mortality if untreated.     

Phlebosclerotic colitis: imaging-pathologic correlation

OBJECTIVE: The objective of this study was to analyze the imaging findings of phlebosclerotic colitis in comparison with histologic findings. CONCLUSION: Calcifications and/or obstructions of the veins of the colonic wall and adjacent mesentery and collateral formation, edematous thickening of the colonic wall, and increased density in the fatty tissue of the surrounding mesentery were features of this rare entity. However, in the early stage of the disease, no definite calcification of the affected veins was observed.     

Spontaneous resolution of a colloid cyst of the third ventricle

We report a case of an asymptomatic colloid cyst of the third ventricle in a 35-year-old male, which on follow-up MRI at 15 months appears to have spontaneously resolved. To our knowledge, this is the first such case reported and supports the role of conservative management of small asymptomatic colloid cysts.     

Changing characteristics of a colloid cyst of the third ventricle

We describe extremely unusual radiological characteristics in a colloid cyst of the third ventricle, where the cyst became dense and its size decreased following a cerebrospinal fluid diversion procedure. Such a course of events has been reported in colloid cysts only twice in the literature. Received: 25 June 1998 Accepted: 23 July 1998     

Focal liver lesions: MR imaging-pathologic correlation

Magnetic resonance signal intensity of focal liver lesions is affected by numerous pathologic factors. Lesion histologic features, such as cellularity, vascularity, stromal component, and intratumoral necrosis or hemorrhage, strongly affect T1 and T2 relaxation times. Additionally, intracellular content of certain substances, such as glycogen, fat, melanin, iron, and copper, may also have a substantial role in determining MR signal behavior. In this review we discuss the correlations between MR imaging features and pathologic findings in benign and malignant focal liver lesions. Knowledge of imaging-pathology correlations greatly assist in charac terizing focal lesions. Moreover, in certain tumor histotypes, such as hepatocellular carcinoma, careful analysis of lesion signal intensity may help predict the degree of tumor differentiation.     

MR imaging of the uterine cervix: imaging-pathologic correlation.

Magnetic resonance (MR) imaging is useful not only for preoperative staging of gynecologic malignancies but also for prediction of the histopathologic features of a variety of intrapelvic tumors. Familiarity with the specific imaging findings that have been reported for the uterine cervix is a goal of radiologists. The typical MR imaging findings of uterine cervical lesions correspond to the histopathologic features. These lesions can be categorized as epithelial neoplasms, nonepithelial neoplasms, and nonneoplastic diseases. Cervical carcinoma accounts for most cases of malignant lesions and is staged by using the classification system established by the International Federation of Gynecology and Obstetrics. MR imaging allows differentiation between endophytic and exophytic growth and between normal and abnormal findings after hysterectomy and irradiation. Other epithelial neoplasms of the uterine cervix include adenoma malignum, which is a special type of cervical adenocarcinoma, as well as carcinoid tumor and malignant melanoma. Nonepithelial neoplasms of the uterine cervix include malignant lymphoma and leiomyoma. Nonneoplastic diseases of the uterine cervix include cervical pregnancy, cervicitis, nabothian cysts, polyps, and endometriosis.     

Magnetic resonance imaging of a colloid cyst of the third ventricle

A case of an isodense non-enhancing colloid cyst of the third ventricle which was not easily diagnosed by computed tomography is described. The patient underwent magnetic resonance imaging which clearly showed a colloid cyst of the third ventricle with accompanying obstructive hydrocephalus. Such lesions are potentially life-threatening if undiagnosed. It is suggested that magnetic resonance imaging has an important role to play in rapidly and clearly demonstrating the location, size and complications of such lesions when there is doubt about the aetiology of obstructive hydrocephalus of the lateral ventricles on computed tomography.     

Colloid cysts of the third ventricle with fatal outcome: a report of two cases and review of the literature

Two cases of sudden death due to colloid cysts of the third ventricle are presented with a review of the literature. In the first case, a 40-year-old woman suffered an acute onset of severe frontal headache after an intercontinental air flight. The next day, she was found comatous and died 7 h after admission to a hospital. In the second case, a 33-year-old man with a medical history of recurrent headaches was found dead in his car. Autopsy in both cases revealed a colloid cyst of the third ventricle and hydrocephalus involving the lateral ventricles. Received: 7 February 1997 / Received in revised form: 2 April 1997     

Hepatic parenchymal perfusion defects detected with CTAP: imaging-pathologic correlation.

To determine whether characteristics of focal hepatic parenchymal perfusion defects detected with computed tomographic arterial portography (CTAP) correlate with underlying pathologic processes, 245 perfusion defects detected with CTAP in 60 patients who subsequently underwent definitive hepatic surgery were characterized by shape, location within the liver, and relative attenuation value and were prospectively correlated with sectioned pathologic specimens. Of 177 round perfusion defects, 102 (58%) were malignant and 75 (42%) were benign. Only one (2%) of 53 peripheral wedge-shaped defects was malignant. All 15 peripheral flat defects were benign. Defects in characteristic locations anterior to the porta hepatis (n = 15) and adjacent to the intersegmental fissure (n = 7) were uniformly benign. While 83 (56%) of 147 soft-tissue attenuation defects were malignant, only four (6%) of 68 intermediate-attenuation defects were malignant. Although these characteristics of parenchymal perfusion defects aid in differentiation of benign from malignant processes, all other types of perfusion defects are nonspecific and may require biopsy.     

Meningioma of the third ventricle

Summary Meningiomas of the third ventricle are rare intracranial neoplasms. We reported such a case in a 42 years old man without clinical evidence of increased intracranial pressure. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the tumour sitting in the superior and anterior part of the third ventricle, bulging into the lateral ventricles. CT was more effective than MRI in the demonstration of calcifications whereas MRI proved to be superior in delineation of the tumour and its relation with surrounding structures.     

Change in CT radiodensity of a colloid cyst of the third ventricle: case report and literature review

A unique case is presented of a decrease in density on CT scans of a colloid cyst of the third ventricle with time. This occurred in the absence of any operative intervention in a 35-year-old woman.     

Mobile intraventricular cyst of the third ventricle treated with stereotactic puncture. Report of a case

A case of a pedunculated arachnoid cyst within the third ventricle is presented. The cyst was small so as not to appear as a significant expanding lesion on CT. The clinical history, however, suggested intermittent increase of the intracranial pressure. On CT there was some widening of the lateral and third ventricles, while the fourth ventricle had normal width. This finding in combination with the clinical history prompted further neuroradiologic examinations, including pneumoencephalography and ventriculography. The presence of a pedunculated mobile cystic lesion within the third ventricle was shown and its nature further elucidated by stereotactic puncture combined with contrast injection into the cyst. After emptying of the cyst, the patient has been free of symptoms during an observation time of 2 years. The diagnostic and differential diagnostic aspects are discussed and the value of traditional neuroradiologic methods emphasized.