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At least 19 recordsLinked to original sources
PubMed1989

Effacement of the fetal cisterna magna in association with myelomeningocele.

The cisterna magna is effaced in association with myelomeningocele. The authors retrospectively investigated the size of the fetal cisterna magna as a predictor of fetal myelomeningocele in 67 pregnant women (17-38 menstrual weeks) referred for prenatal sonography because of an elevated serum alpha-fetoprotein level (n = 61) or a suspicion of fetal ventriculomegaly on previously obtained sonograms (n = 6). Twenty fetuses had myelomeningocele, 14 had isolated ventriculomegaly, and 33 were normal. A normal-sized cisterna magna (range, 4-9 mm in depth) was present in all normal fetuses. In 19 of 20 fetuses with myelomeningocele, the views of the posterior fossa were adequate, and in each of these the cisterna magna was effaced (n = 18) or very small (n = 1). The cisterna magna was effaced in five of 13 (38%) fetuses with isolated ventriculomegaly in whom the posterior fossa was adequately imaged. Although effacement of the cisterna magna is a nonspecific finding, the high negative predictive value of this sign is useful during routine screening of the fetal neural axis.

Cisterna Magna↗
PubMed1978

The mega cisterna magna.

Eleven cases of enlarged cisterna magna were found in a series of 3000 computerized tomography scans. We believe mega cisterna magna by itself is not related to any specific symptoms and may not require further study or treatment.

Adolescent↗
PubMed1988

[A study of cisterna magna on brain computerized tomography in children].

Although many publications on cranial computerized tomography have been reported in recent years, very little attention has been directed to the cisterna magna (CM) and its variations. The size of the cisterna magna is still debatable and the criterion of the mega cisterna magna is obscure. We studied age distribution, clinical manifestations, and other CT findings in the children with enlarged cisterna magna. A consecutive series of 367 computerized tomographic scans were reviewed. We classified four classes according to the degree of enlargement of the cisterna magna: CM is undetectable; CM (-), CM is detectable at the level of sella turcica and the fourth ventricle; CM(+), CM extends upward at the level of suprasellar cistern and colliculus inferior; CM (+ +), and CM extends extensively at the level of the third ventricle and colliculus superior; CM (+ + +). We judged 55 CT scans (15%) to belong to CM (+ + +) class and 100 scans (27%) to CM (+ +) class. The greater part of children with CM (+ + +) were younger in contrast with CM (+ +), which distributed uniformly in every ages. Also we differentiated the patients into three groups from clinical manifestations as follows: patients with developmental delayed; group D, patients with organic neurological diseases; group N, patients with other diseases; group O. The ratio of group D is significantly higher in CM (+ + +) than that of other groups. No children had posterior fossa symptoms of mass effect and required treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Macro cisterna magna: a marker for maldevelopment of the brain?

Enlargement of the cisterna magna occurs in as many as 0.4% of reported patients and generally has been believed to represent a normal variant. Differentiation from Dandy-Walker malformations and other cystic structures has been emphasized. We reviewed 1,260 consecutive computed tomography reports in patients younger than 21 years of age and examined all scans in which enlargement of the cisterna magna was considered an isolated finding. Fourteen patients were identified (incidence: 1%). The primary reasons for obtaining computed tomographic scans included various clinical conditions but excluded symptoms indicative of posterior fossa disease. Developmental or neurologic abnormalities were present in 62% of these patients. Macro cisterna magna should not be dismissed as a normal variant, although the neurologic findings may not be specifically localized to the posterior fossa. This finding may be a marker for abnormal brain function most likely due to subtle disturbances in brain development.

Brain↗
PubMed1992

Linear echoes in the fetal cisterna magna.

Linear echoes are seen in the fetal cisterna magna, (CM) on obstetrical sonography. These echoes often are paired, joining as they descend toward the base of the posterior fossa. Histologic correlation suggests that these echoes are most consistent with dural folds, which likely represent the inferior attachment of the falx cerebelli. A prospective series of 322 prenatal studies was performed in which the sonographer was asked to look for the linear echoes in the cisterna magna and image them. Linear echoes were identified in 84% of all fetuses studied. Identification of these echoes was dependent on CM size, in that they were seen less commonly when the CM was less than 3 mm in diameter. However, their identification was not dependent on gestational age. In addition, 18 fetuses with Dandy Walker cyst or Dandy Walker variant were evaluated and in 16 linear echoes were not seen. We conclude that recognition of normal anatomy within the fetal brain, specifically the fetal CM, is helpful for identifying abnormalities in the size of the CM, whether large or small.

Cisterna Magna↗
PubMed1992

The cisterna magna in second-trimester fetuses with abnormal karyotypes.

Six hundred thirty-eight gravidas at 14-21 weeks' gestation, who were at increased risk for an abnormal fetal karyotype, had sonographic measurement of the fetal cisterna magna at the level of the posterior fossa before genetic amniocentesis. The size of the fetal cisterna magna increased significantly with advancing gestational age in the normal fetus (P less than .001). Twenty-eight fetuses had abnormal karyotypes: 12 with trisomy, eight with translocation or structural rearrangements, seven with sex chromosome abnormalities, and one with triploidy. In each of these fetuses with abnormal karyotypes, the cisterna magna measurement was normal. We conclude that measurement of the fetal cisterna magna at 14-21 weeks' gestation is not useful as a screening test for abnormal fetal karyotype.

Chromosome Aberrations↗
PubMed1992

Allotransplantation of rat islets into the cisterna magna of streptozotocin-induced diabetic rats.

Islets were isolated from the pancreata of Sprague-Dawley rats and transplanted into streptozotocin-induced diabetic outbred Wistar rats. The effect of transplantation of islets into the cisterna magna on the diabetic state of the recipients was compared with that of the conventional transplantation of islets into liver via the portal vein. After successful intraportal (IP) transplantation, rejection took place between days 7 and 15 in all diabetic recipients. All of the eleven rats surviving after stereotaxic implantation of islets into the cisterna magna returned to normoglycemia within 7 days after transplantation. Nine of the recipients with intra-cisterna magna (IM) islet allografts were still normoglycemic at 210 days after transplantation. The glucose disappearance rate of the IM transplant rats was slower than that of the IP transplant rats, and blood glucose returned to the normal basal level within 5 hr following glucose administration. Although the insulin levels were almost undetectable in cerebrospinal fluid before IM transplantation, the insulin levels were markedly increased after IM transplantation and twice as great in CSF than blood. Thus, these findings indicate that the cisterna magna can serve as an immunologically privileged site for implantation of allogeneic pancreatic islets, and islets in CSF can regulate and maintain normal glucose homeostasis via secretion of insulin across the blood-brain barrier.

Animals↗
PubMed1991

Enlarged cisterna magna and the Dandy-Walker malformation: factors associated with chromosome abnormalities.

Thirty-three fetuses with an enlarged cisterna magna (10 mm or more) were evaluated to determine factors that might be associated with an underlying chromosome abnormality. Eighteen fetuses (55%) proved to have a chromosome abnormality, including trisomy 18 or trisomy 18 variant (12), trisomy 13 (three), Turner syndrome (one), or other rearrangements (two). Among various risk factors analyzed, the absence of ventricular dilatation correlated most strongly with a chromosome abnormality. Chromosome abnormalities were found in 17 of 22 fetuses (77%) lacking ventricular dilatation, compared with only one of 11 fetuses (9%) with ventricular dilatation (P less than .001). Other factors statistically associated (P less than .01) with an underlying chromosome abnormality included mild enlargement of the cisterna magna (10-14 mm), concurrent anomalies detected sonographically, and fetal growth retardation. However, stepwise logistic regression showed that only the absence of ventricular dilatation and the presence of concurrent anomalies were significant when multiple factors were evaluated. These observations support the utility of evaluating the cisterna magna as part of a routine anatomical survey.

Cerebral Ventricles↗
PubMed1991

Fetal cisterna magna septa: a normal anatomic finding.

A linear hyperechoic structure in the cisterna magna, previously described as the straight sinus, was investigated during routine obstetric ultrasound (US) examination. One hundred three fetal US examinations were performed to determine the prevalence and appearance of this finding. Also, US water-bath examination of 18 fixed postmortem specimens and fetuses was performed, and results were correlated with those of gross and microscopic examination of the fetal brain. The structure was identified in 95 (92%) prenatal examinations between 15 and 38 menstrual weeks. It was located posteriorly between the cerebellar hemispheres in the cisterna magna. In those 95 cases in which it was identified, it appeared as a single echogenic line in 31 cases (33%), as two echogenic lines in 47 (49%), or as three or more lines in 17 (18%). When two echogenic lines were identified, they appeared "cystlike" in 17 (18%) of the 95 examinations. Correlation of the gross and histologic findings demonstrated these lines to represent normal subarachnoid septa rather than the straight sinus.

Cisterna Magna↗
PubMed1979

Computed tomography of the enlarged cisterna magna.

The unusual appearance of the large cisterna magna on computed tomography is presented and the radiographic signs are reviewed and correlated. This entity may be confused with a variety of other lesions. Awareness of such developmental anomalies may obviate the need for angiography and pneumoencephalography in selected cases.

Adolescent↗
PubMed1987

Gradient of arginine vasopressin concentration but not angiotensin II concentration between cerebrospinal fluid of anterior 3rd ventricle and cisterna magna in dogs.

Dogs were chronically implanted with two devices for cerebrospinal fluid (CSF) sampling from (a) the anterior part of the 3rd ventricle and (b) the cisterna magna. In conscious dogs arginine vasopressin (AVP) concentration of CSF samples collected at different occasions were 2-3 times higher in the CSF of the 3rd ventricle as compared to the AVP concentration of the cisterna magna. Inhalation anesthesia stimulated AVP release into the CSF at both sites by a factor of about 2, the gradient between 3rd ventricle and cisterna magna CSF of 2-3 remained for AVP in simultaneously collected samples. In contrast, angiotensin II-like immunoreactivity of CSF was not significantly different at both sites, neither in the conscious dogs nor during anesthesia. It is concluded that the main amount of AVP enters the CSF at the 3rd ventricular level.

Angiotensin II↗
PubMed1979

Radiology of a large cisterna magna cyst. A case report.

A case of a large cisterna magna cyst presented a problem in differential diagnosis. Characteristic changes were shown on plain skull roentgenograms and on radionuclide brain scan. The diagnosis was established on the basis of pneumoencephalography and isotope cisternography. The lesion responded well to surgical management.

Adolescent↗
PubMed1979

Familial communicating hydrocephalus, posterior cerebellar agenesis, mega cisterna magna, and port-wine nevi. Report on five members of one family.

This report deals with a family in which the maternal grandmother, the mother, and all three male children have port-wine nevi and mega cisterna magna. Two of the three male children have, in addition, congenital communicating hydrocephalus associated with agenesis of the posterior cerebellar vermis. This case of familial communicating hydrocephalus, posterior cerebellar vermis agenesis, port-wine nevus, and mega cisterna magna represents a new neurocutaneous syndrome, possibly transmitted as an autosomal dominant.

Adult↗
PubMed1991

Cisterna magna microdialysis of 22Na to evaluate ion transport and cerebrospinal fluid dynamics.

Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting 22Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of 22Na dialyzed. This hypothesis is supported by the 22Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the 22Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system.

Acetazolamide↗
PubMed1988

Differential effects of cisterna magna cannulation on beta-endorphin levels in rat plasma and cerebrospinal fluid.

The concentration of beta-endorphin-like immunoreactivity (beta-ELIR) was determined in plasma and cerebrospinal fluid (CSF) of rats at various times following the implantation under Hypnorm anesthesia of a permanent cannula into the cisterna magna. Plasma beta-ELIR levels were highly increased immediately after the operation, and gradually returned to basal within 6 h. The beta-ELIR concentration in CSF followed a completely different pattern. It appeared to be rather stable during the first hour after the operation, was decreased at 2 h, and showed a marked increase 24 h after surgery. Two days after the surgery, beta-ELIR levels in CSF had decreased to a stable basal level which was maintained for at least 7 days. When at this stage animals were treated with Hypnorm, plasma beta-ELIR was again highly increased 30 min and not 24 h after injection, but no changes were found in the beta-ELIR concentration in CSF. These data indicate that implantation of a cannula into the cisterna magna induces postoperative changes in the CSF levels of beta-endorphin that are detectable up to at least 24 h later. Moreover, the lack of correlation between CSF and plasma levels of beta-ELIR points towards differences in the regulation of brain and pituitary pro-opiomelanocortin cells.

Animals↗
PubMed1992

Monitoring of neurotransmitter amino acids by means of an indwelling cisterna magna catheter: a comparison of two rodent models of fulminant liver failure.

Alterations of brain and cerebrospinal fluid amino acids have consistently been described in human and experimental fulminant liver failure. To evaluate the significance of such changes in the pathogenesis of hepatic encephalopathy in fulminant liver failure, brain and cerebrospinal fluid amino acids (glutamate, aspartate, GABA, glycine, taurine) were measured at various stages during the development of neurological dysfunction in rats after hepatic devascularization or thioacetamide treatment to induce acute liver failure. To facilitate repetitive removal of cerebrospinal fluid, a technique employing long-term implantation of cisterna magna catheters in conscious, freely moving rats was developed. Brain but not cerebrospinal fluid concentrations of the excitatory amino acids glutamate and aspartate were reduced in both animal models of fulminant liver failure in parallel with deterioration of neurological status. Brain and cerebrospinal fluid GABA levels were not significantly altered. Cerebrospinal fluid glycine levels were increased two to three times in parallel with increasing brain glycine content in the devascularized rat but were unchanged in thioacetamide-induced liver failure, suggesting distinct pathophysiological mechanisms in these two experimental situations. On the other hand, onset of coma in both animal models of fulminant liver failure was accompanied by significantly increased cerebrospinal fluid taurine levels. We suggest that such changes result from taurine release from astrocytes in brain into the extracellular fluid; this is consistent with taurine's role in the regulation of intracellular osmolarity in brain. Sequential measurements of amino acids in the cerebrospinal fluid of small rodents with indwelling cisterna magna catheters adds a useful new approach for exploring the neurobiology of hepatic encephalopathy in fulminant liver failure.

Amino Acids↗