Reference Values for Transverse Cerebellar Diameter Throughout Gestation

Abstract

The transverse cerebellar diameter (TCD) is well established in the ultrasound literature as a reliable parameter for estimating the duration of gestation. In cases of growth restriction the cerebellum is usually spared, making TCD a reliable indicator of gestational age even when other parameters fall off the appropriate growth curve. The purpose of this study is to establish normal values for the transverse diameter of the cerebellum in pathology specimens, and to determine if these values correlate with those obtained by ultrasound. We examined 96 specimens ranging from 14 to 42 weeks gestational age and found that our values correlate well with those published in the ultrasound literature. Mean TCD with 2 standard deviations for each gestational week were determined as reference values.

A pathological approach to anomalies of the posterior fossa

“…Ultrasonographers routinely measure the dimensions of both spaces and tissue. However, the former often disappear when the cranial vault is opened and the brain removed (Pinar et al, 2002;Siebert and Kapur, 2002). This limits the comparison of sonographic and pathologic diagnoses, a problem that has been noted in several studies (Isaksen et al, 1998;Carroll et al, 2000;Tsao et al, 2002;Phillips et al, 2006).…”

“…Cerebellar width also serves as an anatomic indicator for a phenomenon known as brain sparing and is an approach recognized by clinicians and pathologists alike (Lee et al, 1991;Pinar et al, 2002). A normal cerebellar width within the context of ongoing IUGR indicates that brain growth has proceeded in an essentially normal fashion (i.e., has been spared the effects of growth restriction); growth of the brain differs from extracranial growth and is in this way asymmetric.…”

“…By contrast, pathologists have not given cerebellar morphometry much attention until recently (Pinar et al, 2002;Siebert and Kapur, 2002). In the past, cerebellar hypoplasia was assessed subjectively in the laboratory by visual means and/or by weighing.…”

Sonographic Maturation of Third-Trimester Cerebellar Foliation after Birth

“…TCD is one way of measuring development of the cerebellum (8,(15)(16)(17). TCD consists of the width of two hemispheres and the vermis.…”

“…TCD can be measured with ultrasound and used to determine duration of gestation and intrauterine growth restriction (6,7). Normal values for TCD have also been established postmortem (8). Ultrasound imaging through the posterolateral fontanelle adds benefit to routine neonatal cranial sonography (9).…”