Cerebellar cortical dysplasia: MR findings in a complex entity.
(9/185)
BACKGROUND AND PURPOSE: MR imaging findings of cerebellar cortical dysplasia have been described as a new cerebellar malformation. The purpose of this study was to assess the association of cerebellar cortical dysplasia with other cerebral malformations. METHODS: We retrospectively reviewed 46 MR examinations of patients presenting with developmental delay, hypotonia, and facial deformities to identify abnormal folia or fissures or both within cerebellar hemispheres or vermis suggesting cortical dysplasia. RESULTS: Cerebellar cortical dysplasia was diagnosed in 17 patients. In two patients, it was isolated. In the remaining 15 patients, the malformation was associated with vermian malformation (n=11), cerebral cortical dysplasias (n=8), dysplasia of corpus callosum (n=6), and heterotopia (n=5). A widespread malformation of the posterior fossa was observed in eight patients (Dandy-Walker, Chiari II and III, and hypoplasia of brain stem). One patient with hypertrophied cerebellar hemisphere had minor enlargement of the right cerebral hemisphere and lateral ventricle. He also had nodular heterotopia, suggesting unilateral megalencephaly. CONCLUSION: Our study suggests that cerebellar cortical dysplasias are common in cases with more widespread cerebral malformations. Technical progress providing high-quality tridimensional MR imaging of the cerebellum may explain its recent descriptions. (+info)
CSF flow measurement in syringomyelia.
(10/185)
BACKGROUND AND PURPOSE: CSF circulation has been reported to represent a major factor in the pathophysiology of syringomyelia. Our purpose was to determine the CSF flow patterns in spinal cord cysts and in the subararachnoid space in patients with syringomyelia associated with Chiari I malformation and to evaluate the modifications of the flow resulting from surgery. METHODS: Eighteen patients with syringomyelia were examined with a 3D Fourier encoding velocity imaging technique. A prospectively gated 2D axial sequence with velocity encoding in the craniocaudal direction in the cervical region was set at a velocity of +/- 10 cm/s. Velocity measurements were performed in the larger portion of the cysts and, at the same cervical level, in the pericystic subarachnoid spaces. All patients underwent a surgical procedure involving dural opening followed by duroplasty. Pre- and postoperative velocity measurements of all patients were taken, with a mean follow-up of 10.2 months. We compared the velocity measurements with the morphology of the cysts and with the clinical data. Spinal subarachnoid spaces of 19 healthy subjects were also studied using the same technique. RESULTS: A pulsatile flow was observed in syrinx cavities and in the pericystic subarachnoid spaces (PCSS). Preoperative maximum systolic cyst velocities were higher than were diastolic velocities. A systolic velocity peak was well defined in all cases, first in the cyst and then in the PCSS. Higher systolic and diastolic cyst velocities are observed in large cysts and in patients with a poor clinical status. After surgery, a decrease in cyst volume (evaluated on the basis of the extension of the cyst and the compression of the PCSS) was observed in 13 patients. In the postoperative course, we noticed a decrease of systolic and diastolic cyst velocities and a parallel increase of systolic PCSS velocities. Diastolic cyst velocities correlated with the preoperative clinical status of the patients and, after surgery, in patients with a satisfactory foraminal enlargement evaluated on the basis of the visibility of the cisterna magna. CONCLUSION: CSF flow measurement constitutes a direct evaluation for the follow-up of patients with syringomyelic cysts. Diastolic and systolic cyst velocities can assist in the evaluation of the efficacy of surgery. (+info)
Surgical management of syringomyelia-Chiari complex.
(11/185)
Great variety exists in the indications and techniques recommended for the surgical treatment of syringomyelia-Chiari complex. More recently, magnetic resonance (MR) imaging has increased the frequency of diagnosis of this pathology and offered a unique opportunity to visualize cavities inside the spinal cord as well as their relationship to the cranio-cervical junction. This report presents 18 consecutive adult symptomatic syringomyelia patients with Chiari malformation who underwent foramen magnum decompression and syringosubarachnoid shunting. The principal indication for the surgery was significant progressive neurological deterioration. All patients underwent preoperative and postoperative MRI scans and were studied clinically and radiologically to assess the changes in the syrinx and their neurological picture after surgical intervention. All patients have been followed up for at least 36 months. No operative mortality was encountered; 88.9% of the patients showed improvement of neurological deficits together with radiological improvement and 11.1% of them revealed collapse of the syrinx cavity but no change in neurological status. None of the patients showed further deterioration of neurological function. The experience obtained from this study demonstrates that foramen magnum decompression to free the cerebro-spinal fluid (CSF) pathways combined with a syringosubarachnoid shunt performed at the same operation succeeds in effectively decompressing the syrinx cavity, and follow-up MR images reveal that this collapse is maintained. In view of these facts, we strongly recommend this technique, which seems to be the most rational surgical procedure in the treatment of syringomyelia-Chiari complex. (+info)
Unilateral aplasia of the middle cranial fossa floor in atypical hemifacial microsomia.
(12/185)
We present the first report of a patient with atypical hemifacial microsomia (HFM) and unilateral aplasia of the floor of the middle cranial fossa, glenoid fossa, and portions of her posterior fossa. The patient also developed a Chiari I malformation with cervical syrinx over a 3-year interval. This case report highlights the critical role of imaging in revealing serious, but clinically occult, structural abnormalities, as well as the evolution in the pathogenetic understanding of HFM. (+info)
Disturbances of sexual potency in patients with basilar impression and Arnold-Chiari malformation.
(13/185)
Sexual impotence is common in patients with basilar impression and/or Arnold-Chiari malformation. There is no evidence of hypogonadism and testicular biopsy is usually normal. An autonomic disturbance is postulated. (+info)
The clivus-supraocciput angle: a useful measurement to evaluate the shape and size of the fetal posterior fossa and to diagnose Chiari II malformation.
(14/185)
OBJECTIVE: To obtain a nomogram of the clivus-supraocciput angle as a basis for the diagnosis of Chiari II malformation in fetuses with ventriculomegaly. METHODS: A cross-sectional study was undertaken on 310 normal pregnant women of 16-34 weeks' gestation. A mid-sagittal section of the fetal skull was obtained and the angle between the clivus and the supraocciput was measured. Forty-four fetuses with ventriculomegaly due to various causes (13 Chiari II malformation, 12 dysgenesis of the corpus callosum, 7 aqueductal stenosis, 6 borderline ventriculomegaly, 3 Dandy-Walker malformation, 2 porencephaly, 1 schizencephaly) were also included in the study and the values of the angle found in the pathological cases were compared with those found in the normal population. RESULTS: The clivus-supraocciput angle did not change during gestation and was almost constant with an average value of 79.3 +/- 6 degrees. All cases of Chiari II malformation showed a value below the 5th centile of our nomogram. CONCLUSIONS: The evaluation of the posterior fossa and particularly the measurement of the clivus-supraocciput angle is a useful parameter to differentiate the various causes of fetal ventriculomegaly and particularly to recognize Chiari II malformation. (+info)
Power Doppler imaging of the fetal upper aerodigestive tract using a 4-point standardized evaluation: preliminary report.
(15/185)
OBJECTIVE: Our investigation of fetal swallowing has identified potential limitations in the use of color Doppler imaging for detection of amniotic fluid flow and discrimination of respiratory from ingestive activity. The objective of this study was to evaluate an alternative imaging modality, power Doppler sonography, as a technique to enhance detection of amniotic fluid flow in the upper aerodigestive tract. METHODS: We applied a standardized 4-axis sonographic examination of upper aerodigestive structures and used power Doppler imaging to document amniotic fluid flow. Normal aerodigestive activities from 62 healthy control subjects were compared with 4 abnormal cases. RESULTS: Our longitudinal experience with 66 subjects showed that a directed evaluation of the fetal upper aerodigestive tract with power Doppler imaging provided a systematic approach for studying the physiologic development of this region in both healthy and at-risk fetuses. CONCLUSIONS: A standardized 4-axis examination with power Doppler imaging is a useful adjunct in addressing ingestive and respiratory functions in the developing fetus. (+info)
Brain expansion in the chick embryo initiated by experimentally produced occlusion of the spinal neurocoel.
(16/185)
The brain expands in the early chick embryo from pressure generated by accumulation of cerebrospinal fluid (CSF) in a closed neural tube. The sealing of the neural tube occurs as the result of occlusion of the spinal neurocoel rostral to and before closure of the posterior neuropore. We have previously demonstrated the dependence of normal brain expansion upon intraluminal pressure. We had yet to demonstrate, however, that brain expansion actually depends upon natural occlusion of the spinal neurocoel. To demonstrate such dependence, we experimentally occluded the spinal neurocoels of embryos 5 hr younger than stage 11 embryos (in which occlusion of the neurocoel occurs naturally). The stage 10 chick embryos were cultured ex ovo and critically staged, and their spinal neurocoels were occluded using microcautery. All embryos were photographed immediately and at 5, 12, and 24 hr after cautery. Serial sections were made of selected embryos, in which the areas of both the brain and the head were measured. Wilcoxon-Mann-Whitney rank-sum nonparametric tests, Hodges-Lehmann estimators, bootstrapping techniques, and resampling randomization tests were used to determine whether the increases in the brain and head areas for the experimental embryos were significantly different from those of the control embryos during three distinct intervals of expansion: 0-5, 5-12, and 0-12 hr. From 0 to 5 hr, the brains of the precociously occluded embryos expanded significantly more than the brains of the non-occluded controls. From 5 to 12 hr, the brains of the embryos with naturally occluded neurocoels grew significantly larger than the brains of the embryos with precociously occluded neurocoels. At 12 hr, there appeared to be no difference in brain size for these two groups. We conclude that the data support the hypothesis that brain expansion is directly dependent upon occlusion of the spinal neurocoel. (+info)