Pontoneocerebellar hypoplasia: definition of MR features

Abstract

We report five patients with pontoneocerebellar hypoplasia. Because the issue of cerebellar malformations is a difficult subject, we tried to define criteria for diagnosis on MRI: a thin flat pons with disappearance of the anterior curve, a small cerebellum with predominant flattening of the hemispheres and shortened cerebellar fissures, in contrast to atrophy. The posterior fossa is not enlarged. We emphasize the probable late onset of the disease in fetal life because of the demonstration of the abnormalities at US during the last trimester of the pregnancy in one patient. Prenatal diagnosis is important because of possible autosomal recessive transmission.

Unilateral Cerebellar Hypoplasia with Different Clinical Features

“…In case of a volume reduction between 25% and 50%, we used the term "moderate," and hypoplasia affecting less than 50% of a cerebellar hemisphere was defined as "mild." The term "disproportionate cerebellar hypoplasia" was used to describe cerebellar hypoplasia with abnormal cerebellar shape, and the term proportionate cerebellar hypoplasia was used to indicate normal cerebellar shape in the presence of hypoplasia [1,14].…”

Cerebellar haemorrhages and pons development in extremely low birth weight infants

“…An acquired pontocerebellar atrophy should be differentiated from congenital pontocerebellar hypoplasia (association of pons, vermis and cerebellar hemispheres hypoplasia) revealing a neurodegenerative disorder. Acquired forms of pontocerebellar atrophy have been described in association with fetal drug exposure (14), sepsis in premature babies (15), twin-to-twin transfusion syndrome (16) and vascular undersupply (17). We used a reproducible and easy to calculate measurement of pons flattening, based on standard MR scans, to demonstrate that cerebellar haemorrhages are associated with pons abnormality in ELBW with the youngest.…”

Diagnostic imaging of posterior fossa anomalies in the fetus and neonate: Part 1, normal anatomy and classification of anomalies

“…The importance of the mid-sagittal plane during prenatal ultrasound is reiterated here, as this plane helps to evaluate the brainstem and the anatomy of the vermis. Global hypoplasia may be due to infections, aneuploidy or may be associated with a syndrome [48,49]. The cerebellum can also be focally dysplastic, which can occur due to infarctions, hemorrhage or developmental.…”