Prenatal abnormal features of the fourth ventricle in Joubert syndrome and related disorders

Abstract

Joubert syndrome and related disorders (JSRD)

Fourth ventricle index: sonographic marker for severe fetal vermian dysgenesis/agenesis

“…described the normal 4V as having an APD < ⅔ of the cerebellar AP diameter and a width < ½ of the TCD. Quarello et al . described the 4V as a quadrangular anechoic space, with its APD smaller than its LLD.…”

“…Qualitative assessment requires observation of the cerebellar 'butterfly-shaped' structure and the CM 6-8 . However, examination of the 4V has not yet been incorporated routinely into this assessment, despite the fact that its normal anatomic features have been described and its morphological assessment is known to be important for the characterization of MB-HB anomalies 3,5,9,10,14,16 . Bronshtein et al 13 described the normal 4V as having an APD < 2 / 3 of the cerebellar AP diameter and a width < 1 / 2 of the TCD.…”

“…Bronshtein et al 13 described the normal 4V as having an APD < 2 / 3 of the cerebellar AP diameter and a width < 1 / 2 of the TCD. Quarello et al 10 described the 4V as a quadrangular anechoic space, with its APD smaller than its LLD. They described, in fetuses with JSRD, an abnormal shape of the 4V in the axial plane as being elongated along the anteroposterior axis, as a result of the dysgenesis of the brainstem isthmus, and thin laterolaterally, as the SCP are thickened.…”

Diagnostic Value of Prenatal MR Imaging in the Detection of Brain Malformations in Fetuses before the 26th Week of Gestational Age

“…[18][19][20] No sensitivity data are available in this regard: the 2 relatively largest series (of 3 and 7 cases of molar tooth malformation), with a total of 4 cases with early diagnoses (before 25 weeks' GA) by MR imaging or US, were affected by a selection bias; because these cases were within a possible recurrence exclusion prospective protocol, the scanning technique and radiologist were likely to be particularly focused on highlighting minimal heralding signs. 21,22 At an early GA, besides the presence of a smaller vermis and abnormal fourth ventricle shape on midsagittal sections, the definitive evidence of a molar tooth footprint in the midbrain-superior cerebellar peduncle complex may often be visible in only 1 single axial section, unless more axial acquisitions are acquired with different tilting though the brain stem under the guidance of an a priori hypothesis. In our fetus at 22 weeks' GA, we reported a smaller vermis according to the reference data, 23 with an anteroposterior diameter of 4 mm and a superior-inferior diameter of 7 mm, but we did not detect the molar tooth footprint in midbrainsuperior cerebellar peduncles, which was visible on only 1 section (On-line Fig 1B and -C).…”

The Normal and Pathological Fetal Brain

“…7.72 ) Pugash et al 2011 ). Also, the kidneys are hyperechoic in half of all cases ), (Quarello et al 2014 ).…”