A Novel Radiological Score System to Assess the Clinical Severity in Patients with Acute Cerebellitis.

To develop a radiological score system to assess the severity of acute cerebellitis (AC) and to compare radiological severity score at the onset to cerebellar atrophy at follow-up. Clinical and MRI findings were recorded in 16 patients with AC. Radiological severity score considering topographic patterns, gray/white matter involvement, enhancement, tonsillar herniation or hydrocephalus development and clinical severity score taking into account clinical symptoms were assessed for each patient at the onset of the symptoms. Radiological and neurological sequelae were assessed at follow-up. At symptoms onset, clinical severity scale ranged from mild to severe and radiological severity score ranged from 3 to 7 with higher scores indicating a greater severity. The cut-off value of 5 for radiological score well segregated severe patients defined by clinical scale. A significant correlation between clinical scale and radiological severity scores (p < 0.001, r = 0.75) was found. At follow-up visit, all children developed cerebellar atrophy and 5 children showed neurologic sequelae while adults showed complete resolution without atrophy. Patients in whom atrophy was not observed had both older ages (p < 0.001) and a focal cerebellar involvement (p = 0.03). In patients with AC, radiological severity score may be a useful tool in evaluating clinical severity, but it is not capable to predict neither neurological sequelae nor evolution towards atrophy. Cerebellar atrophy, observed in children with AC, may be caused by several factors such as the age of patient and the extension of cerebellar involvement and it may be counterbalanced by neuronal restoring processes due to neuroplasticity.

Costello syndrome: Analysis of the posterior cranial fossa in children with posterior fossa crowding.

This study aimed to assess changes in the posterior cranial fossa (PCF) to shed light on the mechanism of cerebellar herniation in children with Costello syndrome (CS) and posterior fossa crowding. We performed a morphovolumetric PCF analysis on brain magnetic resonance imaging (MRI) in seven children with CS (mean age 31 ± 16 months) comparing the MRI scans with those of seven age-matched healthy subjects.PCF volume (PCFV), PCF brain volume (PCFBV) and cerebellar volume (CeV) were assessed on axial T2-weighted MRI. Morphometric parameters (diameters of the foramen magnum, tentorial angle, basiocciput, supraocciput, basisphenoid and exocciput lengths) were measured on sagittal T1-weighted MRI. The volume of the cerebrospinal fluid (CSF) spaces was calculated as PCFV minus PCFBV.Five out of seven CS children showed tonsillar herniation in the upper cervical canal; no child had hydrocephalus but three out of seven children showed ventriculomegaly. In addition, the PCFV/PCFBV ratio, PCFV, CSF spaces volume, basiocciput, basisphenoid and exocciput lengths and latero-lateral and antero-posterior diameters of the foramen magnum were significantly reduced, whereas no significant changes were found in supraocciput length, PCFBV, CeV or hindbrain volume. The volumetric reduction of the PCF due to bony posterior fossa hypoplasia is a predisposing factor for developing cerebellar tonsillar herniation through the foramen magnum in children with CS. The altered anatomy of the foramen magnum and upward expansion of the PCF secondary to an increased tentorial slope serves to explain the possible mechanism of cerebellar herniation in patients with CS.