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العنوان
Three-Dimensional Sonographic Calculation of the Volume of Intracranial Structures in Asymmetrically Growth Restricted Fetuses /
المؤلف
Said,Marwa Saber.
هيئة الاعداد
باحث / Marwa Saber Said
مشرف / Maged Ramadan Abo Seeda
مشرف / Noha Hamed Rabei
مشرف / Amr Mohamed El-Helaly
تاريخ النشر
2014
عدد الصفحات
157p.:
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
أمراض النساء والتوليد
تاريخ الإجازة
1/1/2014
مكان الإجازة
جامعة عين شمس - كلية الطب - أمراض النساء و التوليد
الفهرس
Only 14 pages are availabe for public view

from 157

from 157

Abstract

growth restriction is associated with substantive perinatal morbidity and mortality. Fetal demise, birth asphyxia, meconium aspiration, and neonatal hypoglycemia and hypothermia are all increased, as is the prevalence of abnormal neurological development (Paz et al., 0991).
Postnatal growth and development of the growth-restricted fetus depends on the cause of restriction, nutrition in infancy, and the social environment (Kliegman, 0991).
The most common reason for fetal growth restriction is uteroplacental insufficiency, chromosome abnormalities, some fetal abnormalities and fetal infection (Creasy et al.,0999).
Many ultrasound features are associated with uteroplacental insufficiency, and these will vary depending on the severity and duration of the problem (Resnik et al., 0999 ).
The Terminology for classifying fetal growth disorders has specifically expanded over the past 9 decades, from the 1220s growth has been classified by the absolute birth weight value as low birth weight (LBW less than 90500g), very low birth weight (less than 10000g), or macrosomia (more than 90000g) (Baschat et al., 3111).Intrauterine growth restriction (IUGR) is often defined as birth-weight less than the 10th centile for gestation (Baker et al., 3113).
Campbell and Thoms (0911) described the use of the sonographic head-to-abdomen circumference ratio (HC/AC) to differentiate fetuses into the subtypes ”symmetrical,” meaning proportionately small, and ”asymmetrical,” referring to those with disproportionately lagging abdominal growth. They found that although asymmetrical fetuses had relatively larger brains and were ”preferentially protected from the full effects of the growth-retarding stimulus,” they were at significantly greater risk for severe preeclampsia, fetal distress, operative intervention, and lower Apgar scores than their symmetrical counterparts. It is compelling to relate the type of growth restriction to the onset or etiology of a particular insult.
Numerous authors have differentiated between symmetric and asymmetric IUGR pregnancy regarding cause and prognosis. Briefly stated, symmetric IUGR infants are more likely to have an endogenous defect that may preclude normal development. Asymmetric IUGR infants are more likely to be normal, but small in size owing to intrauterine deprivation. Although this classification is helpful in establishing a differential diagnosis and framework for discussion, it is not sufficiently precise to serve as a basis for decisions regarding intervention or viability (Degani, 3110).
The diagnosis of IUGR is non-invasive with few adverse effect, treatment may be available, and early detection and delivery have the potential to improve outcome (Lindqvist and Molin, 3111).
In women with significant risk factors, consideration should be given to serial sonography. Although frequency of examinations varies depending on clinical circumstances, an initial dating examination, ideally in the first trimester followed by a second examination at 39 to 39 weeks, or when clinically indicated, should serve to identify many cases of growth restriction (Cunningham et al., 3111).
Currently, IUGR is still often suspected on the basis of fundal height measurements.A significant lag in fundal height is a 9-cm or greater difference than expected for gestational age.Studies on the use of SFH to detect small fetuses have produced a wide range of sensitivities from 95% to 22% (Persson,0912).
Women with risk factors for growth restriction should be considered for ultrasound assessment of fetal growth during their pregnancy in addition to serial symphyseal-fundal height measurement (Hui and Challis, 3111).The next step is to assess the condition of the fetus through Doppler analysis of the fetal circulation and, often the maternal circulation. At the first visit, if no obvious reason for the growth restriction is found and the Dopplers are reassuring, the patient can then be scheduled for a fetal growth recheck in 9 weeks (Lindqvist et al., 3111).
It has been shown that 595 of stillbirth are associated with IUGR (Froen et al.,3112) and 105 of perinatal mortality is a consequence of IUGR (Richardus et al.,3111).
There is also significant neonatal morbidity and concerns over longterm neurological outcomes (Valocamonico et al., 3111).
Pregnancies with IUGR require a close monitoring that represents the best compromise between the risks of neonatal prematurity and the risks arising from a prolonged uterine life for a fetus with growth restriction Pregnancy management and delivery timing depends on the oxygen -metabolic -maternal - placental -fetal balance, evaluated and by combined methods of prenatal diagnosis (Gonzales et al.,3111).
Woman with a suspected growth- restricted fetus should undergo ”high-risk” intrapartum monitoring, incidence of cesarean delivery is increased (Nelson and Grether, 0991).The infant may need expert assistance in making a successful transition at birth (Nelson and Grether, 0991).
There is no question that the practice of perinatal medicine has changed due to advances in radiology, particularly ultrasound (Merz et al.,0991).
The role of 3-D US in obstetrics is evolving rapidly. There are many advantages in using this modality including more accurate diagnosis about fetal abnormalities (Pretorius et al., 3111).
Ultrasound features of uteroplacental insufficiency include placental abnormality (lakes, calcification, jelly-like consistency) and reduction in amniotic fluid volume. Fetal features include mild cardiomegaly, hyperechoic bowel and small bowel dilatation. The presence of these features would support the diagnosis of uteroplacental insufficiency (Gembruch et al., 0991).
Doppler findings typical of uteroplacental insufficiency include: uterine artery notches, absent/reversed end-diastolic flow in the umbilical artery and arterial redistribution (Baschat et al., 3110).
The ability to perform volume calculations using three-dimensional (3D) ultrasound has been hailed as a valuable tool in addition to standard fetal biometry. It may offer potential advantages such as more accurate estimation of fetal weight, as in the case of fractional thigh volume, or assessment of organ functionality, as in considering lung volume as a predictor of postnatal lung hypoplasia (Lee et al., 3119).
Such volume calculation has now been described form a variety of fetal organs and structures. In the majority of cases this is accomplished by manual organ segmentation, using one of two methods: the multiple parallel plane method (multiplanar) or the rotational Virtual Organ Computer-aided AnaLysis (VOCAL) (Rousian et al., 3101).
The fetal brain volume (BV) and perfusion is crucial both in the evaluation of fetal growth and central nervous system development. In the past, human fetal BV could only be assessed indirectly by two-dimensional (9D) ultrasound (US), assuming the BV had an ideal geometric shape, which of course can be an inaccurate assumption (Endres et al., 3110).
With the advent of three-dimensional (3D) US, there is an easy and noninvasive approach to assess all possible planes and views whenever the targeted-scanned 3D volume is obtained, including the fetal brain (Chang et al., 3112).
This study aimed to evaluate the feasibility and reproducibility of volume segmentation of fetal intracranial structures using three-dimensional (3D) ultrasound imaging, and to estimate differences in the volume of intracranial structures between asymmetrical intrauterine growth-restricted (IUGR) and appropriate for-gestational age (AGA) fetuses.
The current study was a cohort prospective study that was conducted at fetal care unit of Ain Shams University Maternity hospital. A group of 32 asymmetrical IUGR and 32 AGA fetuses matched by gestational age (21 week) between 39wks and 32wks had been studied.
All eligible patients were properly counseled and gave informed consent before entry into the study, detailed history was taken, general examination, abdominal examination to assess fetal growth. Routine 9D ultrasound examination for fetal anatomical evaluation and standard fetal biometry, including biparietal diameter (BPD) and head circumference (HC) was performed.
All ultrasound examinations was performed using a medison x 2 (serial number a2950290220290) ultrasound machine with a 9–2-MHz curvilinear probe and an internal device for automatic acquisition of frames for volume reconstruction.
Brain volumes were obtained by trained operators and were stored on digital devices for further analyses.
The frontal, thalamic and cerebellar volumes were segmented manually using 9D view offline analysis software and VOCAL. There was statistical significant difference between frontal lobe volume in both groups which was larger in AGA group than asymmetrical IUGR group.
There was no statistical significant difference between both groups as regard thalamus volume however after adjustment of BPD in both groups the thalamus lobe volume was significantly larger in IUGR group than in AGA group.
The cerebellum volume was statistically larger in AGA group than in asymmetrical IUGR group, and this was the same result after adjustment of BPD in both groups.