Prenatal Sonograms Research Articles

Fetal cephaloceles: diagnosis with US.

The prenatal sonograms of 15 fetuses with cephaloceles (13 occipital, one ethmoidal, and one frontoparietal) were retrospectively reviewed. The prognosis for fetuses with cephaloceles was poor: Only three of 14 with follow-up were born alive (21%), and all are likely to be handicapped. Karyotypes were abnormal in four of nine fetuses tested (44%). Associated cranial abnormalities observed in various numbers of fetuses included ventriculomegaly, the "lemon" sign, a flat basioccipital, "beaked" tectum, and bone defect. A wide variety of neural and nonneural anomalies were associated with cephaloceles. At least one sonographically observed concomitant neural or nonneural axis abnormality or an abnormal karyotype was present in nine of 15 fetuses (60%). Some associated neural malformations noted pathologically were not observed prenatally. Cranial meningoceles were not accurately distinguished from encephaloceles sonographically, and they also were associated with a poor prognosis. Comparison of findings in fetuses with cephaloceles with those of 15 fetuses with cystic hygromas revealed that the two abnormalities can usually be distinguished by the relationship of the mass with the neck and by other cranial findings present in fetuses with cephaloceles but absent in association with cystic hygromas.

Obstructed uterovaginal anomalies: demonstration with sonography. Part I. Neonates and infants.

The sonograms of five neonates with an obstructed urogenital sinus and four with an obstructed cloaca were retrospectively reviewed to determine the sonographic features and the role of pre- and postnatal sonography in the diagnosis and management of hydrocolpos. On pre- and/or postnatal sonograms, the obstructed genital tract was visualized in seven neonates as a large cystic pelvic-abdominal mass, which was the markedly distended urine-filled vagina. One neonate had multiple cystic masses, which resulted from an obstructed duplex genital tract. In one of the neonates with an obstructed cloaca, the anomaly was not diagnosed. The bladder was compressed by the distended vagina and was not visualized in five patients. A vaginal fluid-debris level in six patients was a key finding that distinguished the vagina from the bladder. Obstruction of the urinary tract was an associated feature. An obstructed uterovaginal anomaly with renal dysplasia and oligohydramnios on prenatal sonograms indicates a poor prognosis. Sonography contributes to the diagnosis of an obstructed genital tract and helps define the internal genital anatomy.

Congenital Wilms' tumors are mostly (benign) mesoblastic nephromas--significance of prenatally detected solid kidney tumors

In a nationwide study (1980-1988) for the diagnosis and treatment of Wilms' tumours (nephroblastomas), which are highly malignant embryonal mixed tumours of the kidney and show distant metastases at the time of diagnosis in 10-20% of cases, 78% of 373 children had a standard type Wilms' tumour, 7% had benign variants and 14% had high grade malignancy variants of the classical type. 20 of the 25 benign variants occurred in infants. From the 25, 16 tumours were congenital mesoblastic nephromas, 14 of which occurred in infants. As the detection of a solid renal tumour mass in the prenatal sonogram (showing an echotexture resembling that of the liver) may suggest Wilms' tumour, we analysed 11 neonates (1-14 days old), in which Wilms' tumours had been diagnosed (n = 11; 2.9%) for the histological subtype. In 9 of the 10 neonates, the final diagnosis was congenital mesoblastic nephroma. These congenital mesoblastic nephromas are cured by surgery alone. Thus, if a solid renal tumour suspected as a Wilms' tumour, is prenatally detected, the most probable diagnosis is that of the benign variant congenital mesoblastic nephroma, and, in this case, preterm delivery (e.g. to prevent metastasising and to start treatment as early as possible) is not indicated.

Importance of prenatal detection of hydronephrosis of the upper pole.

To determine the impact of prenatal detection on neonates with hydronephrosis of the upper pole of a duplex collecting system, we reviewed 40 such cases seen between June 1982 and April 1989. This six-per-year rate contrasts with fewer than one case per year that was seen at our hospital from 1947 to 1977. Nineteen patients had an ectopic ureterocele, and 21 had an ectopic ureter without a ureterocele. Thirty-three (83%) were girls. Thirty-three cases were discovered because of abnormal findings on a prenatal sonogram, and 20 of those infants were asymptomatic. In the 33 patients whose prenatal sonographic findings were abnormal, the sonogram was diagnostically precise for hydronephrosis of the upper pole of a duplex collecting system in only 39%. This imprecision did not adversely affect management or outcome. Postnatal sonography modified the prenatal diagnosis in 75% of these 33 patients. Voiding cystourethrography was the most sensitive and precise imaging technique for detecting both ureterocele and reflux. Lower pole reflux was almost twice as common when an ectopic ureterocele was present (63%) than when one was not (33%). Prenatal sonographic detection of hydronephrosis of the upper pole of a duplex collecting system decreased the proportion of neonates presenting with urinary tract infection and urosepsis because of prophylactic antibiotics initiated at birth and continued until surgical correction. Precise prenatal diagnosis was not needed for effective surgical treatment.

Mild lateral cerebral ventricular dilatation in utero: clinical significance and prognosis.

The medical records of 55 fetuses with sonographically diagnosed mild ventriculomegaly (MVM) were reviewed to assess prognosis. Fetuses were divided into two groups based on the presence or absence of sonographically detected associated fetal anomalies: 13 had no other anomalies detected (isolated MVM), and 42 had concomitant neural axis and visceral anomalies (nonisolated MVM). Mortality was 83% among fetuses with nonisolated MVM and 38% among fetuses with isolated MVM (P less than .005). If terminated pregnancies are excluded, only one of nine (11%) fetuses with isolated MVM died, compared with nine of 16 (56%) fetuses with nonisolated MVM (P less than .005). There are 15 living children: Nine (60%) are developmentally normal at 6-30 months of follow-up (six had isolated MVM), three (20%) are or are likely to be abnormal, and we were unable to follow up three (20%). Fetal anomalies were missed in 11 of 30 (37%) fetuses with detailed follow-up. However, this would have changed the classification from isolated to nonisolated MVM in only one case. Thus, in 54 of 55 cases (or 29 of 30 cases with detailed follow-up), fetuses were accurately classified as having isolated or nonisolated MVM. The authors conclude that sonographically isolated MVM is associated with a significantly better prognosis than nonisolated MVM, and fetuses can be classified accurately based on prenatal sonograms.

Fetal Central Nervous System Abnormalities

The advances in the sonographic imaging of the fetus have made the detailed examination of the fetal central nervous system (CNS) a routine part of the prenatal sonogram. A logical sonographic approach to the diagnosis of fetal CNS abnormalities is presented, based on the normal sonographic anatomy and the understanding of CNS pathology. This approach results in a classification of CNS abnormalities derived from ultrasound findings. The main categories are (1) hydrocephalus, (2) entities that mimic hydrocephalus, and (3) neural tube defects. Once a disorder is classified and all ultrasound abnormalities identified, a differential diagnosis can be developed.

Disparity of amniotic fluid volume and fetal size: problem of the stuck twin--US studies.

The "stuck twin" phenomenon in monochorionic diamniotic (MCDA) pregnancies is characterized by marked disparity in both fluid volume and fetal size between the twin gestations. To determine the prevalence, sonographic characteristics, and clinical outcome of this phenomenon, discharge summaries, placental pathologic reports, and prenatal sonograms from 307 twin pregnancies were reviewed. Of 52 cases of MCDA pregnancies, 18 (35%) demonstrated marked disparity in amniotic fluid volume. In 16 of these 18 cases there was discordant twin growth, further suggesting the diagnosis of twin transfusion syndrome. All 16 cases and an additional nine cases supplied by another center demonstrated a small, morphologically normal fetus in an oligohydramniotic sac suspended anteriorly (72%) or laterally (28%) in the uterus. The amniotic membrane separating this twin from the larger twin in the polyhydramniotic sac was thin, closely applied to the smaller fetus, and difficult to detect. Perinatal morbidity was 100% for all twin pairs, and premature labor occurred in all cases. Perinatal mortality ranged from 88% for the larger/poly twin to 96% for the small/oligo twin.

Prenatal diagnosis of sirenomelia.

Prenatal sonographic findings of sirenomelia (or mermaid fetus) were retrospectively reviewed in eleven proven cases. Sonography showed oligohydramnios in all the cases, five (45%) of which had severe oligohydramnios that limited prenatal diagnosis by poor visibility. In five cases (45%), sirenomelia was correctly diagnosed by ultrasound; in the remainder, only bilateral renal agenesis was identified. All eleven fetuses had other associated malformations: congenital heart defects (4), skeletal deformities (10), and abdominal wall defects (4). Death resulted from termination of pregnancy in six cases and stillbirth in three cases. Two newborns died at 24 and 36 hours of neonatal life, respectively. We concluded that some cases of sirenomelia can be detected on prenatal sonograms by demonstration of a single lower extremity, oligohydramnios, and bilateral renal agenesis. Sirenomelia is a lethal condition and can be detectable in the second trimester of pregnancy, allowing for termination of pregnancy.

Neonatal Ovarian Cysts: Sonographic-Pathologic Correlation

The authors reviewed the prenatal (11 infants) and postnatal (17 infants) sonograms and the clinical, surgical, and pathologic findings in 17 infants with an ovarian cyst to determine the sonographic features and natural history of neonatal ovarian cysts. An uncomplicated cyst (nontwisted, nonhemorrhagic) was completely anechoic and the cyst wall was imperceptible with sonography (five cases). A twisted or hemorrhagic cyst was cystic with a fluid-debris level, cystic with a retracting clot, septated with or without internal echoes, or solid (12 cases). These complicated cysts contained liquid and/or organized hematoma. Eleven of the 12 complicated cysts had a thin, highly echogenic wall. Cyst torsion commonly occurred in utero and could be diagnosed on prenatal sonograms by a typical sonographic appearance (eight cases). All of these infants were asymptomatic after birth. Four infants with hemorrhagic or twisted cysts were symptomatic. All cysts except one that resolved spontaneously were treated surgically, including three twisted cysts that showed no change in size over a 1-8-month interval. All of the cysts were of follicular origin.

Prenatal diagnosis of sacrococcygeal teratoma: sonographic-pathologic correlation.

The prenatal sonograms of 15 fetuses with sacrococcygeal teratoma were reviewed to determine the sonographic appearance and the role of sonography in the obstetric management. Each tumor appeared as a large mass arising from the fetal rump. The teratomas exhibited three sonographic patterns: nine were mixtures of cystic and solid components in equal proportions, four were predominantly solid with a few scattered anechoic areas, and two were unilocular cystic masses. Calcifications were detected in six cases. There was no correlation between the sonographic appearance and the presence of immature or malignant components. Ultrasonography allowed visualization of an intraabdominal component in six cases and assessment of findings that were of prognostic importance. Prenatal detection and size determination of the external component can play an important role in planning obstetric management because fetuses with a large tumor should be delivered by cesarean section to avoid dystocia and catastrophic hemorrhage during delivery.

Neonatal ovarian cysts: sonographic-pathologic correlation.

The authors reviewed the prenatal (11 infants) and postnatal (17 infants) sonograms and the clinical, surgical, and pathologic findings in 17 infants with an ovarian cyst to determine the sonographic features and natural history of neonatal ovarian cysts. An uncomplicated cyst (nontwisted, nonhemorrhagic) was completely anechoic and the cyst wall was imperceptible with sonography (five cases). A twisted or hemorrhagic cyst was cystic with a fluid-debris level, cystic with a retracting clot, septated with or without internal echoes, or solid (12 cases). These complicated cysts contained liquid and/or organized hematoma. Eleven of the 12 complicated cysts had a thin, highly echogenic wall. Cyst torsion commonly occurred in utero and could be diagnosed on prenatal sonograms by a typical sonographic appearance (eight cases). All of these infants were asymptomatic after birth. Four infants with hemorrhagic or twisted cysts were symptomatic. All cysts except one that resolved spontaneously were treated surgically, including three twisted cysts that showed no change in size over a 1-8-month interval. All of the cysts were of follicular origin.

Prenatal diagnosis of anencephaly: spectrum of sonographic appearances and distinction from the amniotic band syndrome.

To document the characteristic sonographic abnormalities of anencephaly and to identify potentially confusing sonographic features, we reviewed 20 cases of anencephaly. All of these cases were diagnosed prenatally with sonography after 14 menstrual weeks in patients who were seen at our institution between 1984 and 1988. In all cases, the correct diagnosis was made on the prenatal sonograms and was confirmed pathologically. The sonographic diagnosis was primarily based on the absence of brain and calvarium superior to the orbits on coronal views of the fetal head. This typical appearance was altered by the presence of echogenic tissue superior to the orbits in nine (45%) of 20 cases. Pathologically, the tissue corresponded to angiomatous stroma (area cerebrovasculosa) and appeared quite sizable on sonograms in four fetuses (20%). It may appear solid or mixed solid and cystic. In one fetus, it appeared brainlike. Despite this appearance, the sonologist should not be dissuaded from the diagnosis of classic anencephaly. Hydramnios occurred in seven (35%) of 20 patients, and oligohydramnios occurred in none of the patients. Anencephaly may be distinguished from the cranial defects associated with the amniotic band syndrome (amputation defects that occur as the sequelae of amniotic disruption) on the basis of the symmetry of the cranial defects (100% of anencephalic fetuses in this series) and the absence of limb, body wall, and spinal abnormalities that typically accompany the amniotic band syndrome. Although there may be minor variations in the sonographic appearance of the cranial defect of anencephalic fetuses (i.e., much or little angiomatous stroma), we conclude that this anomaly can be accurately detected and diagnosed on fetal sonograms obtained after 14 weeks menstrual age and distinguished from the amniotic band syndrome.

Luteal phase defect : Daya S, Ward S, Burrows E: Progesterone Profiles in Luteal Phase Defect Cycles and Outcome of Progesterone Treatment in Patients with Recurrent Spontaneous Abortion. Am J Obstet Gynecol 158(2):225–232, 1988.

Objective: Our purpose was to determine the significance of finding an isolated clubfoot on a prenatal sonogram. Study Design: All fetuses found to have an isolated congenital clubfoot over a 9-year period were retrospectively identified. Fetuses with associated anomalies were excluded. Review of medical records for obstetric and neonatal outcome and pathologic and cytogenic results were tabulated. Results: Eighty-seven fetuses were identified from our database as having isolated clubfoot on prenatal ultrasonography, with complete follow-up available for 68 fetuses. Sixty of the 68 fetuses were confirmed as having clubfoot after delivery (false-positive rate = 11.8%). The male/female ratio was 2:1. Four fetuses (5.9%) had abnormal karyotypes: 47,XXY, 47,XXX, trisomy 18, and trisomy 21. Nine fetuses had hip or other limb abnormalities noted after birth. Other anomalies not detected until delivery included a unilateral undescended testis, ventriculoseptal defects (n = 2), hypospadias (n = 2), early renal dysplasia, mild posterior urethral valves, and a two-vessel cord. Five of the 68 patients (including those with aneuploidy) had pregnancy terminations. Eleven patients were delivered preterm. Conclusion: Karyotypic evaluation is recommended when isolated clubfoot is identified on prenatal sonogram because other subtle associated malformations may not be detected ultrasonographically in the early second trimester. (Am J Obstet Gynecol 1998;178:600-2.)

Fetal jejunoileal atresia with persistent omphalomesenteric duct

A case of fetal jejunoileal atresia in association with persistent omphalomesenteric duct is presented. The dilated stomach and proximal and distal duodenum produced a multiple bubble sign on the prenatal sonogram. The neonate underwent exploratory laparotomy, excision of the persistent omphalomesenteric duct, gastrotomy, and colostomy. Possible causes of jejunoileal atresia are presented.

In utero thickening of the chordae tendinae. A cause of intracardiac echogenic foci.

Asymptomatic hyperechoic foci were noted within the left cardiac ventricular chamber on the prenatal sonograms of 26 patients between 16 and 20 weeks of gestation. Their range of occurrence, the prenatal follow-up in 12 patients and postnatal echocardiograms in six patients, indicate a clinically insignificant congenital anomaly associated with the chordae tendinae.

Anorectal atresia: prenatal sonographic diagnosis.

To determine the prenatal sonographic findings of anorectal atresia (ARA), we retrospectively reviewed 12 proven cases. Sonography showed abnormally dilated bowel segments in five cases (42%), four of which were identified prospectively; at autopsy, two other cases showed mild colon dilatation not evident on sonograms. Bowel dilatation was not associated with the location of atresia or the presence of a fistula, but was possibly related to menstrual age. Eleven fetuses (92%) had significant other anomalies primarily related to the VACTERL syndrome (vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, and limb malformations) and/or the caudal regression syndrome; of these, sonography identified one or more concurrent anomalies in seven cases. In two cases, bowel dilatation was the primary sonographic finding. Death in nine cases resulted from termination of pregnancy (four cases) or perinatal demise (five cases); three patients are still alive. We conclude that some cases of ARA can be suspected on prenatal sonograms by demonstration of dilated colon, and that the sensitivity of this finding may be related to menstrual age at the time of the examination. Distinguishing ARA from other causes of fetal-bowel dilatation is important because of the frequency of concurrent anomalies associated with ARA.

Fetal gastric pseudomasses.

Discrete echogenic areas of 4-12 mm were observed in the fetal stomach on seven prenatal sonograms. The finding was incidental and solitary during the second trimester in six normal pregnancies. It was noted during the third trimester in a case of meconium peritonitis. These echogenic areas displayed a homogeneous texture. They disappeared on repeat prenatal examination in six patients who did not reveal any gastrointestinal symptoms on postnatal follow-up. Although their origin is not certain, these fetal gastric pseudomasses should be interpreted cautiously.

Prenatal diagnosis and natural history of the fetus with a congenital diaphragmatic hernia: Initial clinical experience

To study the accuracy of prenatal diagnosis and define the natural history of fetal congenital diaphragmatic hernia (CDH), we reviewed experience with CDH at The University of California, San Francisco (UCSF) over the last three years. All nine babies born in our institution (inborns) and six of 11 babies referred from other hospitals after birth (outborns) died, an overall mortality of 75%. All had pulmonary hypoplasia. Forty percent had associated malformations or chromosomal abnormalities, a higher incidence than generally reported. Prenatal sonograms were available in all nine inborn cases. CDH was correctly diagnosed prospectively in only five, but could be recognized retrospectively in all nine cases using the sonographic criteria developed from the study. Polyhydramnios was present in all nine cases; in seven cases sonography was performed because the woman was large-for-dates clinically. There were no false positive interpretations, and when necessary the diagnosis was confirmed by amniography. All nine cases of CDH detected in utero died. Seven deteriorated so rapidly that surgical repair could not even be attempted. Two who had optimal care (maternal transport, immediate resuscitation and operation) died after repair despite maximal intensive care including vasodilator therapy. Despite the theoretical advantages of maternal transport to pediatric surgical specialty centers, a majority of fetuses with a prenatal diagnosis of CDH will die because their lungs are inadequate to support extra-uterine life even at term.

VALUE OF MATERNAL SONCGRAPHY IN THE DETECTION OF CONGENITAL ABNORMALITIES OF THE URINARY TRACT

During the 1 year period from 1982-1983, 9 cases of congenital urinary malformation referred to our hospital had been detected by maternal ultrasonography. All sonograms were done in the last trimester of pregnancy to evaluate fetal maturity and without suspicion of a possible malformation. All babies had further radiological investigations in the inmediate post natal period including renal sonogram, VCUG and radionuclide renal scan, which correlated well with the prenatal sonogram findings.All 9 patients had unilateral urinary malformations including 2 multicystic kidneys, 1 dysplastic kidney, 3 UPJ obstructions, 2 V.U. Reflux and 1 mesoblastic nephroma.Elective surgical procedures were performed in all cases. These patients accounted for 36% of the congenital urinary malformation diagnosed in the newborn period in our institution during this period of time.The maternal sonogram therefore, represents an important diagnostic tool in the detection of congenital urinary anomalies and may significantly affect the peri-natal management and thus minimize renal damage.