Efficacy of Transcerebellar Diameter/ Abdominal Circumference Versus Head Circumference/Abdominal Circumference in Predicting Asymmetric Intrauterine Growth Retardation

Abstract

Background: The high incidence of IUGR and its low recognition lead to increasing perinatal morbidity and mortality for which prediction of IUGR with timely management decisions is of paramount importance. Many studies have compared the efficacy of several gestational age independent parameters and found that TCD/AC is a better predictor of asymmetric IUGR. Aim:To compare the accuracy of transcerebellar diameter/ abdominal circumference with head circumference/abdominal circumference in predicting asymmetric intrauterine growth retardation after 20 weeks of gestation. Materials and Methods:The prospective study was conducted over a period of one year on 50 clinically suspected IUGR pregnancies who were evaluated with 3.5 MHz frequency ultrasound scanner by a single sonologist. BPD, HC, AC and FL along with TCD were measured for assessing the sonological gestational age. Two morphometric ratios-TCD/AC and HC/AC were calculated.Estimated fetal weight was calculated for all these pregnancies and its percentile was determined. Statistical Methods:The TCD/AC and HC/AC ratios were correlated with advancing gestational age to know if these were related to GA. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy (DA) for TCD/AC and HC/AC ratios in evaluating IUGR fetuses were calculated. Results:In the present study, linear relation of TCD and HC in IUGR fetuses with gestation was noted. The sensitivity, specificity, PPV, NPV & DA were 88%, 93.5%, 77.1%, 96.3% & 92.4% respectively for TCD/AC ratio versus 84%, 92%, 72.4%, 95.8% & 90.4% respectively for HC/AC ratio in predicting IUGR. Conclusion:Both ratios were gestational age independent and can be used in detecting IUGR with good diagnostic accuracy. However, TCD/AC ratio had a better diagnostic validity and accuracy compared to HC/AC ratio in predicting asymmetric IUGR.

Role of Transcerebellar Diameter and Transcerebellar Diameter/Abdominal Circumference Ratio in Assessing Fetal Growth and Diagnosing Intrauterine Growth Restriction

“…Consequently, although the TCD/AC ratio increased slightly as GA increased, this rise was negligible, indicating that the ratio would remain constant regardless of GA. Comparable results were found in the studies that were carried out by Srividya et al and Bhimarao et al [12,15]. In the research carried out by Bhimarao et al, it was found that there was an insignificant association between TCD/AC and GA (r2=0.13, p>0.05) after 20 weeks of gestation [15].…”

“…Comparable results were found in the studies that were carried out by Srividya et al and Bhimarao et al [12,15]. In the research carried out by Bhimarao et al, it was found that there was an insignificant association between TCD/AC and GA (r2=0.13, p>0.05) after 20 weeks of gestation [15].…”

Utilidad de la medición del diámetro transversal del cerebelo fetal para la predicción de la edad gestacional

“…Por lo tanto, su crecimiento está menos afectado por la restricción del crecimiento fetal. Estas características hacen que el DTC sea uno de los parámetros ecográficos más fiables para establecer la EG (6,13,15) . Además, puede ser un parámetro útil en determinadas circunstancias, como presentación de nalgas y dolicocefalia (excepto en la anencefalia), en las que otros parámetros biométricos no son útiles (16) .…”

“…Existe evidencia que el cerebelo fetal presenta crecimiento progresivo a lo largo del embarazo (5) . Además, tanto el cerebro como el cerebelo están menos afectados por la restricción del crecimiento intrauterino fetal secundario a insuficiencia placentaria, lo que sugiere un mecanismo de preservación del crecimiento cerebeloso (6,7) . El diámetro transversal del cerebelo (DTC) es un estimador único y fiable de la EG al final del embarazo (8) .…”

Transcerebellar Diameter for Determination of Gestational Age In Comparison to Conventional Fetal Biometry in The Second Half of Pregnancy

“…In the ultrasound literature, the transcerebellar diameter (TCD) is well-established as a valid metric for determining GA. Because the posterior fossa is not impacted by external pressure such as fetal malposition, breech presentation, or oligohydrammnios, which may result in distortion of the fetal head, TCD may be a more accurate predictor than BPD. When femur length is unsatisfactory due to femoral achondroplasia, the TCD might be utilized instead (4).…”