Height of the cerebellar vermis and gestational age at birth

Effect of Prematurity on Cerebellar Growth

The aim of this study was to evaluate cerebellar growth of preterm infants. Vermis height and transverse cerebellar diameter were measured by cranial ultrasonography in 38 preterm infants (27-32 weeks) at birth and term equivalent age. Measurements were compared with 40 term appropriate-for-gestational-age infants. Preterms at term equivalent age had larger vermis height than term infants (2.39 ± 0.25 cm vs 2.25 ± 0.18 cm, P = .005), whereas no significant difference was found in the transverse cerebellar diameter (5.32 ± 0.38 cm vs 5.44 ± 0.23 cm, P = .13). Vermis height and transverse cerebellar diameter of appropriate-for-gestational-age preterm infants (n = 29) were found larger than small-for-gestational-age ones (n = 9). Vermis height and transverse cerebellar diameter at term equivalent age of appropriate-for-gestational-age preterm infants born before and after 29 weeks of age showed no significant difference. Cerebellar growth is preserved in extreme preterms. However, being small for gestational age may have deleterious effects on cerebellar development.

Assessment of fetal midbrain and hindbrain in mid-sagittal cranial plane by three-dimensional multiplanar sonography. Part 1: comparison of new and established nomograms

OBJECTIVE

To construct nomograms for fetal midbrain (MB) and hindbrain (HB) dimensions, assessed in the mid-sagittal cranial plane by three-dimensional multiplanar sonographic reconstruction (3D-MPR).

METHODS

This was a prospective cross-sectional study of 334 healthy fetuses in low-risk singleton pregnancies between 16 and 35 gestational weeks. All sonographic volumes were obtained by sagittal acquisition. The following MB and HB parameters were evaluated in the mid-sagittal cranial plane using 3D-MPR: MB parameters tectal length (TL) and anteroposterior midbrain diameter (APMD), and HB parameters anteroposterior pons diameter (APPD), superoinferior vermian diameter (SIVD), anteroposterior vermian diameter (APVD) and anteroposterior diameter of the fourth ventricle (APDFV). The measurements were presented as growth charts according to gestational age.

RESULTS

MB and HB biometry were best assessed between 19 and 29 weeks. During this period, adequate visualization was achieved for successful measurement of TL in 90.9% of cases, APMD in 86.6%, APPD in 73.7%, SIVD in 74.2%, APVD in 71% and APDFV in 71%. There was a linear growth pattern, with Pearson correlation coefficients of 0.79 for TL, 0.88 for APMD, 0.91 for APPD, 0.95 for SIVD, 0.88 for APVD and 0.88 for APDFV (P < 0.0001 for each). The mean intra- and interobserver variations for the MB measurements and vermian diameters ranged between 4.3% and 9%. APPD and APDFV showed highest mean variations: 9.0% and 19.4% (intraobserver) and 11.6% and 17.7% (interobserver), respectively.

CONCLUSION

We present new nomograms for assessment of the fetal MB and HB using 3D-MPR in the mid-sagittal cranial plane. To our knowledge, these are the first proposed nomograms for fetal MB dimensions.

Nomograms of cerebellar vermis height and transverse cerebellar diameter in appropriate-for-gestational-age neonates

BACKGROUND

Evaluation of cerebellar morphology and measurement of its biometric parameters such as cerebellar vermis height and transverse cerebellar diameter may assist the neonatologist in monitoring cerebellar growth and development and detect abnormalities resulting from malformations, hemorrhage or ischemic infarction.

AIM

The aim of this study was to establish nomograms of cerebellar vermis height and transverse cerebellar diameter at birth in appropriate-for-gestational-age neonates by using cranial ultrasonography.

STUDY DESIGN

A cross-sectional observational study. Appropriate-for-gestational-age neonates were evaluated with cranial ultrasonography by the same neonatal sonographer.

SUBJECTS

Healthy appropriate-for-gestational-age neonates born between 26 and 42 weeks of gestation in their first postnatal 24 h.

OUTCOME MEASURES

Cranial sonographic measurements included cerebellar vermis height measured midsagitally from anterior fontanelle and transverse cerebellar diameter measured coronally from mastoid fontanelle. Measurements were taken for each gestational age between 26 and 42 weeks and nomograms were constructed.

RESULTS

Three hundred twenty-one consecutively born appropriate-for-gestational-age neonates (163 females and 158 males) were studied. A linear growth function was observed between vermis height and gestational age and between transverse cerebellar diameter and gestational age.

CONCLUSION

Nomograms of cerebellar vermis height and transverse cerebellar diameter against gestational age at birth in appropriate-for-gestational-age neonates have been constructed. This can help the neonatologist to assess variations from the normal during ongoing cerebellar growth and development and to diagnose cerebellar anomalies.

Assessment of gestational age using cerebellar measurements at cranial ultrasound: what is the best approach?

BACKGROUND AND AIMS

Clinical assessment of gestational age (GA) in preterm infants can be challenging. Several ultrasound approaches for estimating GA using cerebellar measurements are reported, claiming to be simpler and more accurate than clinical assessment, but they are not widely used. We aimed to compare the accuracy of four previously described measurements and compare their use in preterm infants.

METHODS

We studied infants <32weeks of GA defined by in-vitro fertilization date or early fetal ultrasound, excluding infants with neurological problems. Vermis anterior-posterior diameter (VAPD), vermis height (VH), and transverse cerebellar diameter via anterior (TCDa) and mastoid fontanelles (TCDm) were measured.Estimated PMA was calculated using published equations, and compared to known PMA using intraclass correlation coefficient (ICC). Intra and inter-observer reliability were determined.

RESULTS

We studied 80 infants (mean GA 28.5weeks [range 24-32], mean post-natal age 5.7days). ICC was 0.761 (VAPD), 0.632 (VH), 0.115 (TCDa) and 0.825 (TCDm). The TCDm equation gave the best estimate of GA (mean estimate -2days; 95% CI±13.8days). TCDa and TCDm absolute measurements were similar for each infant. Accuracy for estimating GA was similar for appropriately grown and small-for-gestation infants. Inter and intra-observer reliability was very good for all measurements.

CONCLUSIONS

Three previously described equations for estimating GA from cerebellar measurements gave good estimates of GA in preterms. The equation described for TCDm gave the narrowest 95% CI. We recommend the TCDm equation for the estimation of GA in VLBW infants but the TCD measurement can be made via either the anterior or mastoid fontanelle.

Cerebral measurements made using cranial ultrasound in term Ugandan newborns

BACKGROUND

Few cUS studies of cerebral measurements are available for normal term infants. Normative data is important for evaluating cerebral structure size in symptomatic term infants and assessing preterm brain growth by term age.

OBJECTIVES

To (i) make linear measurements using cranial ultrasound (cUS) for major cerebral structures and intracranial spaces in normal newborn term infants, (ii) correlate these measurements with gestational age (GA), birth weight (BW), head circumference (HC), gender and within one infant (iii) examine inter/intra-observer variation, and (iv) compare these data with those currently available.

DESIGN, SETTING AND PATIENTS

Linear cUS measurements of major cerebral structures were made in well term-born Ugandan infants at Mulago University Hospital, Kampala. Correlations between the measurements and gender, HC, BW and GA were calculated. Intra- and inter-observer agreements were assessed.

RESULTS

Data from 106 infants (mean GA 39.20±1.4SD weeks) were analysed. Intra/inter-observer agreement was substantial/excellent. Significant correlations were found between HC and pons anterior-posterior diameter (p<0.01), corpus callosal (CC) length (p=0.02) and transverse cerebellar diameter (TCD, p<0.01) and between BW and CC length (p=0.02), vermis height (<0.01) and thalamo-occipital distance (p=0.03); no significant correlation was found with GA. Within infants CC length and TCD correlated significantly (p=0.019). Males had larger left ventricular indices than females (p=0.04). The data was similar to those from other populations.

CONCLUSIONS

These data provide reliable reference values for linear measurements of many cerebral structures made using cUS. The data agree well with those from other populations suggesting that cerebral size is similar in different ethnic groups.

Fetal transverse cerebellar diameter measured by ultrasound does not differ between genders

PURPOSE

The aim of this study was to determine the correlation between fetal transverse cerebellar diameter (TCD) and gestational age of male and female fetus in women under low-risk prenatal care between the 13th and 40th week of gestation.

METHODS

A cross-sectional study was carried out with 184 pregnant women, at the age of 18 years or more, gestational age ranging from 13 to 40 weeks, with a single fetus. A single TCD measurement by ultrasound was used for each fetus. Correlations between fetal TCD and gestational age were determined for the whole sample and each gender separately.

RESULTS

We identified 102 males and 82 female fetuses. A linear correlation was observed between fetal TCD and gestational age for the whole sample (r = 96.9%; p < 0.001). A significant linear correlation was also observed for both males (r = 97.0%; p < 0.001) and females (r = 96.9%; p < 0.001). Comparing the regression lines between genders, no significant difference was observed.

CONCLUSIONS

The data of this study suggest TCD fetal ultrasound as a predictive biometric parameter of gestational age independently of fetal gender in the last two trimesters of a pregnancy.

Sonographic measurements of the fetal fastigium between 20 and 40 weeks' gestation

OBJECTIVE

The purpose of this study was to establish a new reference angle chart for fastigial biometric measurements throughout gestation in normal singleton pregnancies.

METHODS

A prospective cohort study was designed. A total of 505 pregnant women between 20 and 40 weeks' gestation were included in the study. Excluded were those with multiple pregnancies, congenital anomalies, abnormal karyotypes, and polyhydramnios or oligohydramnios. Transvaginal or transabdominal sonography was performed in the midsagittal plane of the brain.

RESULTS

The angle of the fastigium was found to be 30 degrees to 60 degrees throughout pregnancy. These data were found to be constant during the progression of pregnancy without any significant changes.

CONCLUSIONS

Fastigial measurements throughout pregnancy are presented. Its angle is constant throughout pregnancy. Evaluation of the fastigium may assist in cases of subtle posterior fossa anomalies.

Nomogram of the cerebellar vermis height at birth in small-for-gestational-age neonates

AIM

To establish a nomogram of the height of the cerebellar vermis at birth in small-for-gestational-age neonates.

METHODS

Eighty-five consecutively born healthy singletons who were small for gestational age were enrolled in a cross-sectional observational study. The height of the cerebellar vermis was measured by ultrasonography in the midsagittal plane. Reference intervals for the vermian height at 5th, 50th and 95th centiles were estimated at any week of gestational age using a mean and standard deviation model based on least squares polynomial regression.

RESULTS

All attempts at obtaining neonatal vermian height were successful. Mean (standard deviation) maternal age was 29.6 (4.7) years; median parity was 1 (range, 1-3). No difference was found between males and females for the vermian height (mean difference [95% confidence interval], -0.03 [-0.16; 0.10] cm). Mean vermian height (in cm) against gestational age (in weeks) was suitably modelled by a quadratic-cubic polynomial (r2= 0.790, p < 0.0001) as 0.712 + 0.00129 x gestational age2- 0.0000053 x gestational age3 (SD =-1.009 + 0.0504 x gestational age -0.000014 x gestational age3).

CONCLUSION

A nomogram of the height of the cerebellar vermis at birth against gestational age was established for use in small-for-gestational-age neonates.