Prenatal ultrasonic diagnosis of occipital encephalocele

Occipital encephalocoeles in 57 Nigerian children: a retrospective analysis

Fifty-eight patients with occipital encephalocoeles were retrospectively examined. These comprised about one-half of the cases seen and evaluated for treatment at the University College Hospital, Ibadan, Nigeria, between January 1973 and December 1987. There was a female-to-male preponderance of 2:1. Of the patients 91% were treated during infancy. Only one patient was precluded from surgery because his large ulcerated lesion was associated with severe microcephaly and neonatal sepsis, to which he succumbed. About four-fifths of the lesions exceeded 5 cm in diameter. The operative mortality was 6%, all deaths occurring in patients who were neonates at the time of surgery and whose hernia sacs contained brain substance. Clinically apparent hydrocephalus was more frequently encountered postoperatively, than preoperatively. Developmental delay was apparent in 5 of the 13 patients in whom developmental milestones were assessed during follow-up. For most patients, the follow-up period was short, possibly a reflection of the poor prognosis of the disease.

Prenatal diagnosis of fetal malformations by ultrasonography

Ultrasonography is today able to detect many details of the fetal anatomy, so that prenatal diagnosis of malformations becomes possible. However, as 60% of all detected fetal abnormalities develop spontaneously, a screening program is recommended. At least two ultrasonic examinations should be performed. To cope with the huge number of examinations obstetricians in their offices are integrated in this program. Women carrying fetuses with identified or suspected anomalies are sent for further evaluation, management, and counseling to special clinics. The task is to differentiate between lesions which are incompatible with postnatal life, lesions which will necessitate a supporting person for the life of the patient, and lesions which are correctable by surgery. To gain more experience, close cooperation with neonatologists, pediatric surgeons, neurologists, and geneticists is recommended. The first advantages of early prenatal diagnosis have been elective cesarean and reduction of postnatal evaluation and treatment required.

Differential diagnosis of sonographically detected tumours in the fetal cervical region

Differential diagnosis of sonographically detected fetal neck tumours is difficult. The sonographic criteria for encephalomyelocele, lymphangioma/hygroma, teratoma, sarcoma, haemangioma, neuroblastoma and goitre are given on the basis of the authors' own observations and information from the literature. Elevation of alpha-fetoprotein in the amniotic fluid is a frequent but non-specific finding. Chromosome analysis after amniocentesis can be a useful supplementary procedure for assessing the prognosis and deciding upon the delivery procedure. Sonographic detection of a tumour in the fetal neck region enables preparations to be made for dystocia and postnatal dyspnoea of the newborn. The obstetrician must cooperate closely with paediatricians, neurologists, surgeons and ENT specialists.

[Normal and pathological ultrasonography of the fetal brain]

Advanced ultrasonic technology enabled the bidimensional imaging of fetal brain throughout pregnancy. The number of visible structures increases with gestational age. In order to certify the described items they were compared to similar anatomical sections available from brain specimens or an atlas of anatomy. Real-time as well as automatic compound scanning machines were used to obtain echographic images of fetal brain anatomy in utero. Many different scans were collected along three orthogonal directions: every 2 mm, with the automated compound scan and as close from each other as possible with the linear array real-time scanner. The material included 59 normal fetuses between the 15th and 40th week of gestation. Eight typical sections are made but the only structures identified are those being visible on every section obtained at the same level. Brain structures such as grey and white matter, nuclei, vessels and ventricles have different sonic properties. They are subsequently distinguishable on the ultrasonic image if the equipment is capable of detecting and showing such differences. Grey matter is more echogenic than white, choroid plexuses are very reflective as are vessel walls which also pulsate. Four horizontal sections are described in detail (Figs. 2-7). The coronal planes are demonstrated at three different levels (Figs. 8-12) and the sagittal plane is represented by Fig. 13. Thirty five structures were identified (Table 2). In the second section some brain and skull anomalies are briefly described. The principal signs of the abnormalities and possible encountered variations are listed such as cranial defects in anencephaly, acrania, encephalocele, iniencephaly; the anomaly of size and shape of head and ventricle, as in hydrocephaly and microcephaly, cystic-like- and solid-tumor lesions and Dandy Walker syndrome and hydranencephaly. Attention is drawn to possible artifacts and pitfalls in the differential diagnosis between similar looking pictures. Examples are given such as noise in the near field, occurring more often in sectorscan machines, inadequate orientation of scan plane producing asymetrical display of the hemisphere and the Sylvian fissure described as if it was the lateral ventricle wall. Anomalies can also be confused such as exencephaly, anencephaly, iniencephaly, encephalocele. An excellent knowledge of normal brain anatomy and pathology, together with excellent equipment and a careful scrutiny of the echograms are required qualities for fetal brain examination.

Prenatal diagnosis of fetal brain ventricle dilatation

In a 13 month prospective screening programme 3120 pregnant women were examined with diagnostic ultrasound at 17 and 32 weeks gestation; five fetuses (0.16%) were found with dilatation of brain ventricles. Early diagnosis was made in one patient resulting in legal termination of the pregnancy. The four other patients were diagnosed at the second ultrasound examination.

Ultrasonographic diagnoses of major lymphatic system abnormalities prior to 20 weeks of pregnancy

Prenatal ultrasound diagnoses of severe lymphatic system abnormalities were obtained in three fetuses. In all three cases the diagnosis was established prior to 20 wk of pregnancy, i.e. early enough to allow selective termination. In all three cases male fetuses with a chromosomal anomaly were found. Alpha-fetoprotein values were not elevated. In all cases the fetal abnormalities were of such size that surgical excision could not be taken into consideration to provide satisfactory results for the infants.

Prenatal diagnosis--a compilation of diagnosed conditions

This article provides physicians with an up-to-date listing of 182 fetal conditions diagnosed prenatally. This information is presented in two key tables: the first an alphabetical listing of the conditions and the second a grouping of them according to disease categories. The latter table also presents the technique(s) used to establish the diagnosis, as well as pertinent references. Chromosomal abnormalities, diagnosed from amniotic fluid cell karyotypes, have not been individually tabulated in either table. Current techniques utilized for prenatal diagnosis are presented (see Comment).

Maternal ultrasonography for the antenatal diagnosis of surgically significant neonatal anomalies

The increased use of ultrasonography in the management and evaluation of pregnancy has provided a unique opportunity to observe the anatomy of the developing fetus from 12 weeks gestation until term. Twenty-eight surgically important anatomic abnormalities have been diagnosed in utero by sonographic examinations at our affiliated institutions over the past three and a half years. These include ascites (five cases), gastroschisis (four cases), omphalocele (three cases), sacrococcygeal teratoma, cystic hygroma, hydrocele, duodenal atresia, multicystic kidney (two cases each), and one each of jejunal atresia, conjoined twins, ureteropelvic junction obstruction, urethral valves, urethral agenesis, and hydronephrosis secondary to reflux. Prenatal diagnosis by ultrasonographic examination has signifcantly improved perinatal management. Elective caesarean section has benefited infants with lesions causing dystocia, such as sacrococcygeal teratoma, omphalocele, and conjoined twins. Advance notification of surgeons and neonatalogists has reduced the delays of postnatal evaluation and treatment that contribute, significantly, to complications and death. In addition, transfer of the pregnant mother carrying an infant with a significant surgical anomaly to a center with facilities for neonatal surgery and specialized postoperative care can be properly planned for in advance. In the near future, intrauterine fetal surgery or palliative intervention may provide increased salvage of patients with obstructive uropathy and diaphragmatic hernia, both of which carry high mortality rates secondary to in utero damage. Sonography has proven useful in following the dilatation of either intestinal or urinary tract structures in utero. In our hands, maternal sonography has improved the surgical care of the newborn and may open a new frontier of intrauterine fetal surgery in the future.

Diagnosis and assessment of fetal malformation and abnormalities by ultrasound

With remarkable improvements in antenatal, intrapartum and the newborn care, the proportion of perinatal problems attributable to congenital abnormalities has significantly increased. The number of deaths due to fetal malformations in some countries now approaches the number due to prematurity and it is justifiable to believe that abnormalities will soon be heading the league of causes of perinatal death. Even with the most advanced treatment teams and resources, many seriously malformed children cannot be habilitated to any reasonable degree. It is therefore obvious that the future of these types of disorders lies ultimately in their prevention. This has long been the hope of obstetricians and in certain abnormalities this can become a reality. With the advent of ultrasound, many structural anomalies cannot be evaluated by direct visualization of the placenta and fetal anatomy. The number of pregnancies monitored available and as public education about genetics increases. Diagnostic ultrasound has proved to be a powerful means of preventing the birth of babies with significant defects. If this has not been achieved in early pregnancy, the knowledge that the fetus is or may be abnormal at the end of pregnancy can still be valuable, since the management of patients before and during labour could be radically altered. Therefore, ultrasound examination should be preferred as the initial test because it is without risk and produces no side effects.

Ultrasound in the diagnosis of congenital anomalies

With high-resolution ultrasound equipment, it is now possible to diagnose certain fetal anomalies in the third trimester and in some cases before the twentieth week of gestation. During a 27 month period 2,548 ultrasound scans were performed in high-risk patients. An anomaly was diagnosed in 10 of 122 second-trimester patients who were at risk for recurrent fetal defects. Fetal deformity was also found in 26 third-trimester patients. Of the 2.8% of patients found to have polyhydramnios 18% were associated with various types of anomaly. With ultrasound it was possible to examine internal fetal anatomy and to identify abnormalities of the fetal cranium, spine, chest, abdomen, and limbs. These anomalies are reviewed here in detail. Based on ultrasonically derived information, second-trimester patients can be offered information concerning the status of their fetuses at risk genetically and physicians can better manage third-trimester patients with diagnosed fetal deformities.