Metrizamide Computed Tomography Research Articles

Computed tomography of an intracranial lipoma confined in the suprasellar cistern

A case of large intracranial lipoma involving the suprasellar cistern is presented in a 50-yr-old man with a history of occipital headaches. Evaluations by routine computed tomography (CT) combined with metrizamide CT citernography were extremely useful in the diagnosis of this rare condition. Intracranial lipomas are reviewed in the literature and the role of CT evaluations is discussed.

Traumatic atlanto-occipital dislocation in children: Review and report of five cases

Traumatic atlanto-occipital dislocation has usually been considered incompatible with life. However, reports on survivors stress the need for early clinical diagnosis of this condition, particularly in the context of multiple trauma, in order to avoid life-threatening diagnostic manipulations and to provide adequate treatment. Five instances of atlanto-occipital dislocation in children observed during the last two years prompted this report, since four of them survived only temporarily. The radiologic and computed tomographic (CT) findings have been reevaluated. Use of metrizamide CT is advised in clinically suspected cases with inconclusive radiologic workup.

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.

<I>Cauda Equina Neurinoma Associated with Normal Pressure Hydrocephalus</I>

A 45-year-old male was hospitalized because of gait disturbance, urinary incontinence, and memory disturbance. A computed tomographic (CT) scan revealed dilatation of the cerebral ventricles, and a metrizamide CT scan showed reflux into all ventricles. Cerebrospinal fluid obtained at the time of metrizamide CT was highly xanthochromic. Myelograms demonstrated a tumor between the inferior portion of the fifth lumbar vertebra and that of the second sacral vertebra. After removal of a spinal tumor involving nerve fibers at the cauda equina, his symptoms disappeared and the spinal fluid protein normalized. Three months after surgery, a CT scan revealed reduction of cerebral ventricular size. There are 10 reported cases of spinal tumors resulting in normal pressure hydrocephalus. All these and present cases involved protein in the spinal fluid, which might have been the cause of the hydrocephalus.

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.

Cervical Soft Disc

Thirty-five cases of cervical soft disc were analyzed in terms of symptomatic, myelographic, and computed tomographic (CT) features. The patients, 24 males and 11 females, ranged in age from 33 to 69 years (mean, 48 years). The clinical manifestations were classified into six patterns according to the subjective and objective findings. On myelography, lateral views provided useful information in patients with myelopathy, whereas posteroanterior views were more informative in patients with radiculopathy. On the basis of metrizamide CT findings, the herniated discs could be classified as medial, mediolateral, or lateral. According to the operative findings, disc herniation could be characterized as either protruded, with an intact posterior longitudinal ligament, or prolapsed, with laceration of the ligament. A medial orientation was well correlated with protrusion and lateral and mediolateral herniation with prolapse. Although the mechanisms of myelopathy due to cervical soft disc are obscure, both direct compression by the herniated disc material and secondary circulatory disturbance within the spinal cord appear to play important pathogenetic roles.

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.

Spinal Dermoid Cyst: Characteristic CT Findings after Metrizamide Myelography

A 25-year-old male complained of intermittent, sharp pains about the left eye and in the left side of the chest. Neurological examination revealed paresthesia and impaired perception of touch and pin-pricks in the dermatomes of Th8 and Th9 on the left side. In all four extremities, the muscle stretch reflexes were equal and slightly hyperactive, without weakness or sensory deficits. Metrizamide myelography showed defective filling at the level between the upper 8th and 9th thoracic vertebrae. The lesion was also demonstrated by computed tomography (CT) scan performed 1 hour later, appearing as an oval, radiolucent mass in the left dorsal spinal canal, which compressed the spinal cord forward and toward the right. Serial sections of the spinal canal revealed the lesion to be partly filled with contrast medium. Repeat CT scan 24 hours after metrizamide myelography showed more contrast medium in the periphery of the lesion, giving it a doughnut-shaped appearance. At surgery a smooth-surfaced cyst containing sebum and white hair was totally removed from the intradural extramedullary space. The histological diagnosis was dermoid cyst. There have been a few reported cases of intracranial epidermoid cyst in which filling of the cyst was suggested on metrizamide CT myelography. These findings may complicate the differential diagnosis of arachnoid cyst and dermoid or epidermoid cyst when only CT is used.

MRI in infants and children with spinal dysraphism.

Magnetic resonance imaging (MRI) of the spine was used in 37 infants and children to assess the potential of this new technology to evaluate suspected lumbosacral dysraphic myelodysplasia. Eighteen of these patients had correlative metrizamide myelotomography and metrizamide computed tomography (CT). MRI using a spin-echo pulse sequence with short repetition times (TR) and echo delay times (TE) affords optimal delineation of normal and abnormal spinal cord morphology in the lumbosacral region. Coronal projections usually provide an adequate demonstration of the normal conus medullaris for screening purposes; however, multiplanar acquisitions are necessary for more complete delineation of the dysraphic myelopathy. The sensitivity of MRI compares favorably with metrizamide tomography and CT, although these procedures provide somewhat better specificity. These results suggest that MRI is a reliable, noninvasive procedure to screen patients for lumbosacral dysraphism.

MRI of the chronically injured cervical spinal cord.

Thirteen patients with prior cervical spinal cord injury resulting in quadriplegia were evaluated with magnetic resonance imaging (MRI) long after their initial injury, either because of the relatively recent onset of new and worsening neurologic symptoms or to rule our residual compression on the spinal cord or nerve roots. The results of MRI were compared with delayed metrizamide computed tomography (CT) in 10 cases, and in five of those the results were also compared with intraoperative spinal sonography. It was found that MRI more accurately demonstrated the intramedullary abnormalities in the injured spinal cord than did delayed metrizamide CT because the former could separate myelomalacia from a posttraumatic spinal cord cyst, a differentiation that was frequently difficult with delayed metrizamide CT. T2-weighted spin-echo pulsing sequences with long echo times were particularly useful in evaluating these patients.

Spinal Cord Compression from an Intradural Arachnoid Cyst

A case of spinal cord compression from an intradural arachnoid cyst in the thoracic region is reported. The patient was a 59-year-old female. She had noted thoracic girdle pain and urinary trouble for 2 years. Neurologically, she showed muscle atrophy and weakness of the right leg, and loss of all sensory modalities below the 7th thoracic cord (Th7) level bilaterally. Metrizamide myelography showed no abnormal findings, but computed tomography (CT) following the metrizamide myelography demonstrated marked enlargement of the subarachnoid space and remarkable rightward and ventral displacement of the spinal cord. During surgery it was noted that the spinal cord was severely compressed by an arachnoid cyst from Th4 through Th6. After this operation, neurological deficits disappeared completely. Most spinal intradural arachnoid cysts arise in the region of the septum posticum in the thoracic portion. Various etiologies have been postulated. Although conventional myelogram has been the most important form of examination, intradural arachnoid cysts may be filled incompletely or not at all in the myelography performed in a prone position, because they mostly locate on the dorsal aspect of the spinal cord. There are some reported cases in which intradural arachnoid cysts were found a few hours after myelography. Therefore it is not so easy to diagnose intradural arachnoid cysts with conventional myelography. With metrizamide CT myelography, intradural arachnoid cysts can be visualized more easily.

MR imaging of syringomyelia and hydromyelia.

The relative effectiveness of plain computed tomography (CT), metrizamide CT, conventional myelography, and magnetic resonance (MR) imaging was compared for the examination of cystic spinal cord lesions. Intramedullary cavities in 18 patients were demonstrated by MR imaging: cavities were uncomplicated in 13 patients, associated with spinal tumors in two, and studied after occipital craniectomy for treatment of Chiari malformation and syringomyelia in two. Cavities were shown by MR imaging in all enlarged spinal cords, but a cavity was shown in only one of four small cords. The rostral limits of the cavities were demonstrated better than were the caudal extensions. Ventricular communication was not demonstrated. Chiari malformation was shown only in cavities that did not involve the medulla. Syringes associated with tumor were indistinguishable from uncomplicated cavities, but the tumor had abnormal signal on long spin-echo sequences in two cases. Cystic cord tumor (one case) had an inhomogeneous appearance. Caudal displacement of the cerebellar hemisphere through the surgical defect associated with compression of the fourth ventricle was shown in two cases after posterior fossa craniectomy. Thirteen patients were studied with metrizamide CT also. MR imaging proved to be as accurate as metrizamide CT in the diagnosis of intramedullary cavities that result in spinal cord enlargement, but it was less sensitive in detecting cavities within normal-sized or diminished spinal cords. It had the advantage that tumor tissue could be distinguished from associated syrinx cavities by differences in signal characteristics; and cerebellar ectopia was evaluated easily on sagittal MR views.

Metrizamide CT myelography in cervical myelopathy and radiculopathy: correlation with conventional myelography and surgical findings

Conventional myelography, metrizamide computed tomographic (CT) myelography, and surgical findings were correlated in 30 patients with cervical radiculopathy and/or myelopathy. In 60% of patients, metrizamide CT myelography provided significant additional information including better characterization of the abnormality, lateralization if the conventional myelogram was indeterminate, more definitive demonstration of cord atrophy, foraminal narrowing not appreciated on myelography, and demonstration of abnormalities distal to a myelographic block. In no case was a myelographic abnormality not detected on metrizamide CT myelography. In patients with cervical myelopathy, a cross-sectional diameter of the cord equaling less than 50% of the subarachnoid space is predictive of poor patient response to surgical intervention.

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.

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.

Intraoperative spinal sonography: adjunct to metrizamide CT in the assessment and surgical decompression of posttraumatic spinal cord cysts

Ten patients with prior spinal cord trauma were examined preoperatively by metrizamide computed tomography (CT) and were studied subsequently by intraoperative spinal sonography. On comparing intraoperative sonography with metrizamide CT, it was found that metrizamide CT tends to overestimate the size and number of posttraumatic cysts, that areas of myelomalacia on metrizamide CT correspond to areas of abnormal echogenicity on intraoperative sonography, and that intracyst septations are seen only on intraoperative sonography. By monitoring the position of the shunting catheter during surgery, intraoperative sonography can assure its proper intramedullary placement and demonstrate the successful decompression of the cyst. If no cyst is found with intraoperative sonography, further surgery is obviated. Intraoperative sonography is recommended for all cases where decompression of cord cysts is planned.

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.

Brain stem gliomas in childhood. Rational approach and treatment.

Thirty-six infants and children with brain stem glioma diagnosed between 1967 and 1980 were reviewed. Posterior fossa craniotomy was performed in 25, with biopsy or partial resection in 18, cyst aspiration in 2, and exploration alone in 5. The 19 surgical specimens obtained revealed neoplastic cells in 15 but only gliosis or blood clot in 4. There was a significant discrepancy in pathological spectrum between autopsy and surgical specimens. The review of the literature shows that 51.6% of autopsy confirmed tumors were malignant while 26.8% of surgically biopsied tumors were benign. Since biopsy specimens often misrepresent the true pathology, we felt that surgery undertaken to obtain precise histological verification of brain stem gliomas is futile. Rather, we employ computed tomography (CT) with high-resolution metrizamide CT cisternography to distinguish surgically resectable extra-axial tumors adjacent to the brain stem from the unresectable intrinsic brain stem gliomas. Radiation therapy is the choice of treatment should CT indicate clear evidence of intrinsic brain stem tumor. However, posterior fossa craniotomy should be undertaken only for aspiration of cystic intrinsic stem tumors, resection of extra-axial juxtastem tumors and, although rare, in instances when CT is unable to definitively distinguish extra-axial from intra-axial mass for verification of lesion location.

Computed tomography in the evaluation of the optic chiasm

Computed tomography (CT) is the procedure of choice for initial evaluation of patients suspected of having chiasmal or perichiasmal lesions. Over 1000 patients were examined with high resolution CT, using axial and coronal scans, contrast enhancement, multiplanar reformations, and, when indicated, metrizamide CT cisternography. The normal anatomic appearance of the chiasm and neighboring structures is demonstrated, as are various pathologic conditions. CT criteria suggesting chiasmal disease are: (1) symmetric or asymmetric enlargement of the chiasm; (2) areas of abnormal density, without or with contrast enhancement, in the chiasm or perichiasmal region; (3) alteration of the suprasellar cistern; and (4) distortion of the anterior-inferior third ventricle.