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Elka Miller, Liat Ben-Sira, Shlomi Constantini and Liana Beni-Adani

Object

The goal of this study was to determine the importance magnetic resonance (MR) imaging holds as a complementary fetal imaging modality to ultrasonography in deciding postnatal neurosurgical management.

Methods

Between 1999 and 2003, 320 fetal MR imaging studies were performed at a single institution. Twenty-four fetuses were found to have central nervous system abnormalities that could potentially require a neurosurgical intervention. The diagnoses included spinal anomalies (scoliosis, myelomeningocele, and closed spinal dysraphism) and brain anomalies (ventriculomegaly with or without hemorrhage, intracranial cyst, craniosynostosis, and encephalocele).

Fourteen of the 24 fetuses underwent surgery based on findings of prenatal MR imaging. In seven cases the pregnancy was terminated, and in three cases conservative follow up continues.

Conclusions

In a variety of brain and spine disorders, prenatal MR imaging can delineate and characterize the abnormality, and thus assist in the diagnosis and in the planning of postnatal surgery and management. This modality provides important multiplanar images and may obviate the need for early postnatal computed tomography or MR imaging. Postnatal management can often be guided by prenatal MR imaging findings.

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Suhas Udayakumaran, Naresh Biyani, David P. Rosenbaum, Liat Ben-Sira, Shlomi Constantini and Liana Beni-Adani

Object

Trapped fourth ventricle (TFV) is a rare late complication of postinfectious or posthemorrhagic hydrocephalus. This entity is distinct from a large fourth ventricle because TFV entails pressure in the fourth ventricle and posterior fossa due to abnormal inflow and outflow of CSF, causing significant symptoms and signs. As TFV is mostly found in children who were born prematurely and have cerebral palsy, diagnosis and treatment options are a true challenge.

Methods

Between February 1998 and February 2007, 12 children were treated for TFV in Dana Children's Hospital by posterior fossa craniotomy/craniectomy and opening of the TFV into the spinal subarachnoid space. The authors performed a retrospective analysis of relevant data, including pre- and postoperative clinical characteristics, surgical management, and outcome.

Results

Thirteen fenestrations of trapped fourth ventricles (FTFVs) were performed in 12 patients. In 6 patients with prominent arachnoid thickening, a stent was left from the opened fourth ventricle into the spinal subarachnoid space. One patient underwent a second FTFV 21 months after the initial procedure. No perioperative complications were encountered. All 12 patients (100%) showed clinical improvement after FTFV. Radiological improvement was seen in only 9 (75%) of the 12 cases. The follow-up period ranged from 2 to 9.5 years (mean 6.11 ± 2.3 years) after FTFV.

Conclusions

Fenestration of a TFV via craniotomy is a safe and effective option with a very good long-term outcome and low rate of morbidity.

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Liat Ben-Sira, Noam Goder, Haim Bassan, Shlomi Lifshits, Yaniv Assaf and Shlomi Constantini

OBJECT

The object of this study was to use diffusion tensor imaging (DTI) to evaluate and characterize white matter changes in hydrocephalus.

METHODS

The authors performed a retrospective analysis of DTI in a cohort of patients with hydrocephalus (n = 35), 19 of whom had both pre- and postsurgical imaging studies. These patient’s DTI values were compared with values extracted from age-dependent trend lines computed from a healthy subject group (n = 70, age span 14 months-14 years). Several DTI parameters in different regions of interest (ROIs) were evaluated to find the most sensitive parameters for clinical decision making in hydrocephalus.

RESULTS

Compared with healthy controls, patients with active hydrocephalus had a statistically significant change in all DTI parameters. The most sensitive and specific DTI parameter for predicting hydrocephalus was axial diffusivity (λ1) measured at the level of the corona radiata. Diffusion tensor imaging parameters correlated with several conventional radiological parameters in the assessment of hydrocephalus but were not superior to them. There was no convincing correlation between clinical disease severity and DTI parameters. When examining the pre- and postsurgical effect, it was found that DTI may be a sensitive tool for estimating tissue improvement.

CONCLUSIONS

This large-cohort study with a multidisciplinary approach combining clinical, neurological, radiological, and multiple DTI parameters revealed the most sensitive DTI parameters for identifying hydrocephalus and suggested that they may serve as an important tool for the disorder’s quantitative radiological assessment.

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Ben Shofty, Liat Ben-Sira, Anat Kesler, George Jallo, Mari L. Groves, Rajiv R. Iyer, Alvaro Lassaletta, Uri Tabori, Eric Bouffet, Ulrich-Wilhelm Thomale, Pablo Hernáiz Driever, Shlomi Constantini and for the Isolated Optic Nerve Abnormalities (IONA) Collaboration

OBJECTIVE

Isolated optic nerve gliomas (IONGs) constitute a rare subgroup of optic pathway gliomas (OPGs). Due to the rarity of this condition and the difficulty in differentiating IONGs from other types of OPGs in most clinical series, little is known about these tumors. Currently, due to lack of evidence, they are managed the same as any other OPG.

METHODS

The authors conducted a multicenter retrospective cohort study aimed at determining the natural history of IONGs. Included were patients with clear-cut glioma of the optic nerve without posterior (chiasmatic/hypothalamic) involvement. At least 1 year of follow-up, 2 MRI studies, and 2 neuro-ophthalmological examinations were required for inclusion.

RESULTS

Thirty-six patients with 39 tumors were included in this study. Age at diagnosis ranged between 6 months and 16 years (average 6 years). The mean follow-up time was 5.6 years. Twenty-five patients had neurofibromatosis Type 1. During the follow-up period, 59% of the tumors progressed, 23% remained stable, and 18% (all with neurofibromatosis Type 1) displayed some degree of spontaneous regression. Fifty-one percent of the patients presented with visual decline, of whom 90% experienced further deterioration. Nine patients were treated with chemotherapy, 5 of whom improved visually. Ten patients underwent operation, and no local or distal recurrence was noted.

CONCLUSIONS

Isolated optic nerve gliomas are highly dynamic tumors. Radiological progression and visual deterioration occur in greater percentages than in the general population of patients with OPGs. Response to chemotherapy may be better in this group, and its use should be considered early in the course of the disease.

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Li-tal Pratt, Shelly I. Shiran, Ronit Precel, Liat Ben-Sira, Gustavo Malinger, Emanuela Cagnano, Danil A. Kozyrev, Shlomi Constantini and Jonathan Roth

Mature teratomas (MTs) of the posterior fossa are extremely rare. The authors present a case of a prenatal diagnosis of an MT splitting the brainstem. Representative images as well as the clinical and surgical course are presented. Literature regarding “split brainstem” and MT of the posterior fossa is discussed.

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Jonathan Roth, Neal Fischer, David D. Limbrick Jr., Travis CreveCoeur, Liat Ben-Sira and Shlomi Constantini

OBJECTIVE

Solitary posterior fossa low-grade glial tumors (SPFLGT) in children are rarely associated with leptomeningeal dissemination (LMD). To date, there are no clear guidelines regarding the role of screening and surveillance spinal MRI (sMRI) in children with SPFLGT, at diagnosis or during follow-up periods. The current study reviews a cohort of children with SPFLGT, focusing on sMRI findings.

METHODS

In this binational retrospective study, the authors analyzed 229 patients with SPFLGT treated and followed over 13 years. One hundred twelve children had at least 1 total sMRI screening or surveillance examination. One hundred seventeen had no sMRI, but did not present with clinical spinal signs or symptoms. Collected data included demographics, disease characteristics, radiology, pathology, and clinical follow-up data.

RESULTS

For the 112 children with at least 1 sMRI, the mean duration from diagnosis to first sMRI was 11.73 ± 28.66 months (range 0–165 months). All sMRI scans were conducted as screening examinations, with no spinal-related symptoms. One patient was found to have a sacral intradural lesion concurrent to the brain tumor diagnosis. Over the course of 180 radiological and 533 clinical follow-up years for the 112 patients with sMRI, and 582 clinical follow-up years for the 117 patients with no sMRI, there were no additional cases with spinal tumor spread.

CONCLUSIONS

The yield of screening sMRI in the absence of cranial metastasis, or spinal symptoms, is extremely low. Because preoperative sMRI is recommended for medulloblastomas and ependymomas, it may be logical to acquire. During the follow-up period the authors recommend limiting sMRI in patients without symptoms suggesting a spinal lesion, in patients without known cranial metastases, or recurrence or residual SPFLGT.