Metrizamide CT Cisternography Research Articles

Evaluation of periventricular hypodensity in adult hydrocephalus with CT cisternography and xenon-enhanced CT.

Metrizamide CT cisternography and Xenon-enhanced CT were employed to evaluate the periventricular hypodensity (PVH). CT cisternography was performed on adult cases with suspected communicating hydrocephalus, of which 43 cases showing ventricular reflux were investigated. In those cases in which significant transition of metrizamide into the area of PVH was followed after the ventricular reflux and stasis, the shunt operation was effective. The PVH disappeared post-operatively. However, in cases with PVH in which the metrizamide penetration did not occur, the PVH did not disappear post-operatively and clinical improvement was not detected. Xenon-enhanced CT was performed in six cases. Three cases exhibited communicating hydrocephalus, in which the area of PVH was not enhanced by metrizamide with CT cisternography. The other cases demonstrated acute high pressure hydrocephalus. The PVH in the former cases was neither enhanced by Xenon nor metrizamide, while the latter was enhanced significantly. Studies suggested that the reversible PVH was the result of an abnormally increased transition of cerebrospinal fluid through the ependymal layer, while the irreversible PVH resulted from the axonal destruction or demyelination of the periventricular white matter.

Spontaneous cerebrospinal fluid rhinorrhea: A case report and analysis: Erratum.

The diagnosis of CSF rhinorrhea requires the performance of a thorough history and physical examination. Often no objective findings can be found and further evaluation will be required. In our experience, metrizamide CT cisternography yields the most information for localization of the fistula. When indicated, patients can be protected against meningitis by using prophylactic antibiotics for 4-6 weeks to allow a fistula to close spontaneously. If the fistula fails to close during this time, surgical closure with dural or muscle graft with or without waxing of the bone is the treatment of choice.

Neurosurgical Approaches to Cerebrospinal Fluid Rhinorrhea

The evolutionary concepts of pinpointing and treating cerebrospinal fluid (CSF) fistulas over the past few decades are reviewed taking into consideration the dynamic character of CSF circulation. The localization of the site of leakage is greatly facilitated by the judicious use of a variety of radioisotope and radiological techniques. The most recent are Metrizamide CT Cisternography and Magnetic Resonance Imaging. It is asserted that still the most challenging cases are those with intermittent liquorrheas, and those patients in which the site of the fistula is not easily defined. The authors will describe their personal experience with intracranial surgical repair of fistulas located in the anterior fossa.

Spontaneous Cerebrospinal Fluid Rhinorrhea

The diagnosis of CSF rhinorrhea requires the performance of a thorough history and physical examination. Often no objective findings can be found and further evaluation will be required. In our experience, metrizamide CT cisternography yields the most information for localization of the fistula. When indicated, patients can be protected against meningitis by using prophylactic antibiotics for 4-6 weeks to allow a fistula to close spontaneously. If the fistula fails to close during this time, surgical closure with dural or muscle graft with or without waxing of the bone is the treatment of choice.

Surgical indications for infantile subdural effusion

Thirty-four cases of infantile subdural effusion (ISE) were reviewed in relation to surgical treatment and its prognosis during an average of 4 years of extended follow-up. The surgical indications were determined mainly by the size of the ISE on computed tomography (CT) scan and by metrizamide CT cisternography (MCTC). Consequently, 18 cases were categorized as type A according to MCTC, including 11 cases (61.1%) of ISE CT grade 1. All type A cases were closely observed. This nontreatment regimen yielded excellent results in 15 cases (83.3%). For 10 cases categorized as type B according to MCTC, including 5 cases (50%) of ISE CT grade 3, surgical treatment was indicated and excellent results were obtained in 8 cases (80%). For 6 cases categorized as type C according to MCTC and as ISE CT grade 3, surgery yielded excellent results in 4 cases (66.7%). Antiepileptic drugs have been given to three (27.3%) of the 11 patients who had convulsive attacks. In conclusion, the surgical indications for ISE were based mainly on MCTC in addition to the clinical course, and it is emphasized that, in the early stages, surgery on ISE cases categorized as MCTC types B and C is necessary.

Arachnoid Cyst of the Fourth Ventricle

A 65-year-old female was admitted because of progressive vertigo, truncal ataxia, and unsteadiness of gait for the past 6 years. Computed tomography (CT) and magnetic resonance imaging revealed a non-enhanced, large midline cyst in the posterior fossa and slightly dilated lateral and third ventricles. Metrizamide CT cisternography showed no communication between the cyst and the subarachnoid space. Suboccipital craniectomy, laminectomy of the atlas, and membranectomy of the cyst were performed. On light microscopic examination, the cyst wall was composed of arachnoid cells and connective tissues. Thus, this lesion was not an epithelial cyst but an arachnoid cyst occupying the fourth ventricle. An arachnoid cyst of the fourth ventricle is extremely rare, and only two cases were previously reported.

Non-traumatic cerebrospinal fluid rhinorrhea: the "normal pressure leaks".

Non-traumatic cerebrospinal fluid (CSF) rhinorrhea is an uncommon condition. 15 patients with non-traumatic CSF rhinorrhea having "normal pressure leaks" are presented. Metrizamide CT cisternography failed to reveal the site of the fistula in 3 patients. 11 of the 15 patients underwent surgery for closure of the fistulous communication. In 8 of them the fistula was in the anterior fossa, in one it was in the sellar floor and in two the fistula site was not seen either radiologically or at surgery. In all except the one patient with sellar floor defect an intracranial approach was used. 12 patients have been followed up for 6 months to 9 years and 10 (83%) have been cured of their rhinorrhea. The intracranial approach is preferred to an extracranial approach in the repair of anterior fossa fistulae. Conservative treatment may be effective in selected patients.

Overpressure radionuclide cisternography and metrizamide computed tomographic cisternography in the detection of intermittent rhinoliquorrheas in children

The authors present their clinical observations on 25 children treated because of cerebrospinal fluid leakage. In an attempt to improve the detection of rhinorrhea, overpressure radionuclide cisternography (ORNC), combined with the placement of nasal pledgets, was employed in 20 cases. In 16 cases, metrizamide computed tomographic cisternography (MCTC) was performed. In 11 children both types of investigations were done. ORNC was performed as follows: after placing pledgets in each side of the nasopharynx, a lumbar puncture was done and opening, resting CSF pressure was continuously monitored. 99mTc-DTPA (1 ml, 0.5-3.0 mCi) was injected intrathecally and infusion of artificial CSF followed. MCTC was done 1 h after instillation of 5 ml of metrizamide. The rhinorrhea was diagnosed in 14 cases (all cases were verified through operation). In one case with negative ORNC, rhinorrhea was observed 1 week after examination and in the other 4 days after an additional head tap. In the group of MCTC, four results were true-positive, seven true-negative, and five false-negative. Concerning the group of ORNC and MCTC, four cases were false-negative with MCTC, but true-positive in ORNC. In seven cases EEG was performed immediately before and after ORNC and no changes were observed. There were no adverse effects following either type of investigation. In conclusion, the authors state that ORNC seems to be more sensitive in comparison to MCTC in diagnosis of intermittent rhinorrhea. MCTC, however, may be useful for precisely locating the CSF leakage.

Neuroimaging Neuro-Ophthalmology

Computed tomographic scanning is an excellent modality for evaluation of most orbital and intracranial tumors and strokes. However, MR scanning is definitely superior to CT when evaluating for multiple sclerosis, posterior fossa lesions (evaluation of gaze palsies, internuclear ophthalmoplegia, and downbeat nystagmus), or when assessing an area where sagittal scanning is important (chiasmal lesions). Magnetic resonance has increased specificity when the CT is equivocal. Although MR and CT may be complementary in the information they provide, many clinical studies have shown MR to be superior to CT in evaluating cerebral infarctions, hematomas, the intracanalicular optic nerve, optic chiasm, sella turcica, and the cavernous sinus. Magnetic resonance generally has replaced metrizamide CT cisternography as the procedure of choice for evaluating the suprasellar cistern and posterior fossa. Computed tomography is still preferable for major trauma, especially involving acute fractures and hematomas, although MR is more sensitive to the more subtle intracerebral lesions, such as shear injuries and subdural hematomas, that may provide prognostic information. Computed tomography also is preferred in situations where detecting small amounts of calcification is important for the differential diagnosis. As the development of MR imaging continues with faster scan times, finer spatial resolution, the use of paramagnetic contrast agents, and with increased availability and decreased cost, MR imaging may become preferable to CT as the imaging modality of choice for the CNS and orbit.

Loss of Vision due to Cryptococcal Optochiasmatic Arachnoiditis and Optocurative Surgical Exploration

A female patient became blind as a complication of cryptococcal optochiasmatic arachnoiditis. The diagnosis of optochiasmatic arachnoiditis was made by metrizamide CT cisternography. Surgical lysis of the adhesion restored her vision. The diagnosis and surgical treatment of optochiasmatic arachnoiditis in cryptococcal meningitis are discussed.

Metrizamide computed tomographic cisternography: A high-yield diagnostic procedure for chiasmal syndromes with equivocal computed tomographic or magnetic resonance scans

Eight patients with chiasmal syndromes that could not be characterized despite high-resolution computed tomographic (CT) evaluation of the chiasm and suprasellar cistern were evaluated by metrizamide computed tomographic cisternography (MCTC). In all cases, the MCTC was essential in establishing the presence or absence of a structural chiasmal lesion. Although Magnetic Resonance Imaging (MRI) has largely supplanted MCTC as the procedure of choice in CT-negative chiasmal syndromes, the utility of intrathecal contrast computed tomography with cerebrospinal fluid analysis in evaluating chiasmal involvement in pituitary adenomas, craniopharyngiomas, gliomas, and particularly in unusual inflammatory lesions of the chiasm, make it a useful procedure to retain in one's diagnostic armamentarium.

Cranium Bifidum associated with Unusual Intracranial Extension: MRI Findings and Possible Pathogenesis

An atypical, walnut-sized parietal mass was identified in a 9-day-old male. The pregnancy and delivery had been normal. A plain skull X-ray obtained on admission showed a small defect beneath the mass and excessively split sutures, which indicated very high intracranial pressure. A computed tomography (CT) scan revealed a triangular-shaped, low-density area in the falx, extending to the quadrigeminal cistern. Magnetic resonance imaging (MRI) demonstrated a peculiar intracranial extension from the skull defect to the cistern via an intrafalcial sinus-like tract. After excision, it was confirmed by metrizamide CT cisternography that the sinus-like tract was a cerebrospinal cavity. The histological diagnosis was myxofibroma. It was speculated that the mass might have arisen from primitive mesenchymal cells. MRI should be the first diagnostic procedure performed in cases of midline anomalous lesions.

Spontaneous Cerebrospinal Fluid Otorrhea in association with an Aqueductal Stenosis

A case of adult aqueductal stenosis presenting with cerebrospinal fluid (CSF) otorrhea is reported. The patient, a 56-year-old female, was admitted because of CSF otorrhea which had appeared spontaneously for the previous 2 months. Neurological examination on admission revealed bilateral optic atrophy and left conductive deafness. CSF leakage from the left Eustachian tube was confirmed by nasopharyngeal fiberscopy. The skull X-ray and computed tomography (CT) scan were consistent with aqueductal stenosis. Metrizamide CT cisternography showed clouding of the left mastoid air cells and middle ear cavity, presumably due to overflowing of CSF. The patient was gradually relieved of CSF otorrhea after shunt insertion. Spontaneous CSF otorrhea is an uncommon phenomenon and has seldom been described in association with aqueductal stenosis. The authors review the literature and discuss the possible routes of CSF leakage and the treatment for this rare complication.

Fat in the normal cavernous sinus.

The cavernous sinuses of 17 patients examined by metrizamide CT cisternography with 1.5 mm-thick slices were reviewed. Most of the cavernous sinuses contained fatty components. Anterior lateral end and posterior end of the cavernous sinus are the common sites where the fat is visible.

Communicating Triventricular Hydrocephalus and Its Treatment with a Lumboperitoneal Shunt

With computed tomography, triventricular hydrocephalus shows enlargement of the 3rd and both lateral ventricles with a nearly normal size 4th ventricle. Triventricular hydrocephalus has been described as noncommunicating because of aqueductal stenosis or obstruction. The authors, however, have encountered three patients whose computed tomographic (CT) images were those of triventricular hydrocephalus despite a patent aqueduct. This condition may be suitably referred to as communicating triventricular hydrocephalus because in all cases metrizamide CT cisternography demonstrated the communication between the spinal subarachnoid space and both lateral ventricles. The authors discuss its treatment with a lumboperitoneal shunt.

Evaluation of Cerebrospinal Fluid Rhinorrhea by Metrizamide Computed Tomographic Cisternography

Seven interesting and instructive cases of cerebrospinal fluid rhinorrhea evaluated by metrizamide computed tomographic cisternography are presented. The rhinorrhea was spontaneous in three patients and was related to previous head trauma or surgical procedures in four patients. The anatomical site and the extent of the fistula were demonstrated precisely by directly showing metrizamide passing through the bony defect. A combination of bone dehiscence and metrizamide within the adjacent paranasal sinuses or the nasal cavity is also useful in localization. Distortion of the interhemispheric fissure, sylvian fissure, or basal sulci indicates the probability of brain herniation through the defect.

Evaluation of Cerebrospinal Fluid Rhinorrhea by Metrizamide Computed Tomographic Cisternography

Evaluation of Cerebrospinal Fluid Rhinorrhea by Metrizamide Computed Tomographic Cisternography

Intrasellar Epidermoid Cyst

A rare case of an intrasellar epidermoid cyst with ophthalmologic and endocrinological disorders is reported. A 54-year-old male complained of decreased visual acuity and visual field defects. On admission, bitemporal hemianopsia and panhypopituitarism were revealed. Computed tomography (CT) demonstrated a homogeneous low density area in the sellar region. The margin of the low density area was slightly enhanced. The low density area was clearly distinguished from the cerebrospinal fluid space in the metrizamide CT cisternography. The mass lesion was totally removed by the transsphenoidal approach. Histological examination of the surgical specimen showed that the cyst wall consisted of stratified squamous epithelium with keratinization and confirmed the diagnosis of epidermoid cyst.

Magnetic resonance imaging in the evaluation of the brainstem.

Magnetic resonance (MR) images of the brainstem region from 100 normal or asymptomatic individuals were reviewed in addition to those of 17 patients with intra-axial brainstem lesions and 15 patients with extra-axial masses around the brainstem. MR was able to demonstrate consistently the normal anatomy of the brainstem and adjacent cisterns, though the distinction between gray and white matter was seldom possible with the present technology. Masses in and around the brainstem were all accurately identified on MR and its sensitivity was superior to that of x-ray computed tomography (CT). These study results show that despite its technical limitations, MR is presently the examination of choice for the evaluation of brainstem abnormalities and eventually it will undoubtedly replace metrizamide CT cisternography.

早期聴神経しゅようの診断について

This paper is reported about the otoneurological findings and the neuroradiological results containing air or metrizamide CT cisternograpy in the six patients with acoustic tumors less than 1.5cm in size located within the internal auditory canal (intracanal type) or projecting into the cerebellopontine cisterna (cisternal type).1. The six patients had asymmetric neurosensory type hearing impairment and more recruitment phenomena than signs of retrocochlear lesions on the basis of false negative results in this research. Therefore, the ABR test should be used only a screening test.2. The three patients were tested by electronystagmography and their response to the bilateral caloric test was normal.3. Petrous tomograms revealed an enlargement of the internal auditory canal in only three of these patients. Conventional CT scans gave false negative results in five patients. A new radiological technique, air or metrizamide CT cisternography, revealed small acoustic tumors in all six patients. These were confirmed at surgery.