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Biomedical subjects

D H Pretorius

Publications and source records attributed to D H Pretorius.

At least 73 records · Page 4Linked to original sources
PubMed1994

Four-chamber view of the fetal heart: demonstration related to menstrual age.

The four-chamber view of the fetal heart is the most widely used screening examination for the detection of structural cardiac abnormalities during routine fetal ultrasonography. A prospective study of 520 consecutive routine fetal sonograms taken between 13 and 39 weeks of gestational age was performed to determine the frequency of obtaining a satisfactory four-chamber view, focusing on fetuses of less than 19 weeks' menstrual age. Menstrual age was a significant variable in procuring a satisfactory four-chamber view. Visualization of a normal four-chamber view on film progressively increased from five out of 15 (33%) at 14 weeks of menstrual age to 35 out of 38 (92%) at 19 weeks of menstrual age; real-time evaluation improved visualization to six out of 15 (40%) at 14 weeks of menstrual age and to 36 out of 38 (95%) at 19 weeks of menstrual age. Visualization in all fetuses scanned before 19 weeks' menstrual age improved from 62 (on film only) to 75% (real-time and film). Abnormalities on the four-chamber view were demonstrated before 19 weeks of menstrual age in four cases. Although not all serious cardiac defects can be detected, the four-chamber view remains a reliable screening examination of the fetal heart even early in gestation.

Embryonic and Fetal Development↗
PubMed1993

Value of maternal serum alpha-fetoprotein levels of 5.0 MOM or greater and prenatal sonography in predicting fetal outcome.

PURPOSE: To determine fetal outcomes and the capability of sonography to help predict these outcomes in patients with maternal serum alpha-fetoprotein (MSAFP) levels of 5.0 multiples of the median or greater. MATERIALS AND METHODS: Real-time sonography was performed in patients with singleton and multiple gestations. After sonography, the pregnancy was monitored. RESULTS: Inaccurate historical dating caused elevated MSAFP levels in 14 patients. In the remaining 72 singleton gestations, 42 fetuses (58%) had anomalies, 13 (18%) died in utero or after birth, three (4%) had intrauterine growth retardation or were premature, and 14 (19%) were normal, with no complications. A poor outcome occurred in 58 (80%) of the singleton pregnancies, and sonography depicted an abnormality in 49 (84%) of these patients. CONCLUSION: Most pregnant patients with MSAFP levels of 5.0 MOM or greater have an unfavorable outcome. Sonography depicts most of these abnormal pregnancies.

Abdominal Muscles↗
PubMed1993

Twin pregnancies in the second trimester in women in an alpha-fetoprotein screening program: sonographic evaluation and outcome.

OBJECTIVE: We correlated sonographic findings with fetal outcomes in women with unsuspected twin pregnancies who had sonography in the second trimester as part of a screening program for maternal serum alpha-fetoprotein (MSAFP) level and history of neural tube defect. MATERIALS AND METHODS: The study group consisted of 97 women with twin pregnancies who participated in a screening program for MSAFP level and history of neural tube defect. Seventy-three had normal MSAFP levels, 21 had elevated MSAFP levels, and two had low MSAFP levels. One patient had a family history of anencephaly. All 97 patients had sonography during their second trimester of pregnancy. Sonographic findings were reviewed retrospectively for information on gestational age, fetal anomalies, sex of the fetus, location of the placenta, presence and thickness of a dividing membrane, and interpretation of amnionicity and chorionicity. Information on fetal outcome included gestational age at delivery, survival, birth weight, sex, congenital anomalies, obstetric complications, amnionicity, chorionicity, and placental abnormalities. RESULTS: Amnionicity and chorionicity were correctly detected on sonograms in 44 (90%) of 49 diamniotic-dichorionic gestations, 23 (72%) of 32 diamniotic-monochorionic gestations, and two (50%) of four monoamniotic-monochorionic gestations. Fetal anomalies were present at delivery in five neonates and had been correctly detected at sonography in one (hemivertebra); one fetus with duodenal atresia had abnormal sonographic findings in the third trimester. Missed anomalies included absent forearm, cleft lip and palate, and imperforate anus. Sex of the fetuses was correctly predicted on the basis of sonographic findings in 40 of 43 pairs. Nine twin pairs had possible twin-twin transfusion syndrome suspected sonographically on the basis of abnormal fluid volumes, discrepant growth measurements, and abnormal findings on Doppler studies. Outcomes included two confirmed cases of the syndrome (two survivors, two deaths) and three probable cases (six deaths); four pregnancies resulted in eight survivors who were delivered after 34.4 weeks' gestation and had birth weights in the 25th percentile or higher. Survival rates for diamniotic-dichorionic, diamniotic-monochorionic, and monoamniotic-monochorionic gestations were 90%, 91%, and 50%, respectively. Fetuses in women with MSAFP levels greater than 4.5 multiples of the median and with monochorionic placentation had lower survival rates than fetuses in women with normal MSAFP levels and monochorionic placentation (67% vs 96%). Half the fetuses delivered after 20 weeks' gestation had birth-weight discordance of less than 10%. Premature deliveries occurred in 56% of pregnancies. CONCLUSION: The results suggest that (1) sonography is useful in predicting placentation, (2) placentation may be helpful in predicting fetal outcome, (3) increased MSAFP levels correlate with increased perinatal mortality in diamniotic-monochorionic pregnancies, and (4) caution should be taken in diagnosing and determining prognosis for suspected twin-twin transfusion syndrome in the second trimester.

Amnion↗
PubMed1993

Fetal hemivertebrae: associated anomalies, significance, and outcome.

OBJECTIVE: To study fetuses who had the sonographic diagnosis of hemivertebrae made in utero (excluding open neural tube defects) and to determine the incidence of associated anomalies, karyotypes, and neonatal outcome. METHODS: Twenty-seven fetuses with sonographically detected vertebral abnormalities (excluding neural tube defects) and postnatal follow-up were included in the study. Associated structural defects and karyotypic anomalies were tabulated. The outcome for fetuses with isolated vertebral abnormalities on prenatal sonogram was compared with that of fetuses with associated anomalies. RESULTS: Eleven of 27 fetuses had hemivertebrae as the only sonographic anomaly. Nine of the 11 were live-born with a good outcome; one patient elected pregnancy termination, and one fetus died of sepsis after premature rupture of the membranes. Sixteen fetuses had other anomalies including cardiac, intestinal, renal, intracranial, and limb anomalies. Seven of these 16 had Potter syndrome, two of whom also had sacral agenesis. Only five of those with additional anomalies survived; five died and six pregnancies were electively terminated. Because four of the six aborted fetuses had Potter syndrome (renal dysgenesis), a lethal malformation, a total of at least nine of the 16 fetuses with other anomalies would not have survived. All seven fetuses with severe oligohydramnios had lethal anomalies. Eighteen fetuses underwent karyotyping (including all those with isolated vertebral anomalies), and all had normal karyotypes. CONCLUSION: Our study suggests that sonographically diagnosed, isolated fetal vertebral anomalies carry a good prognosis and the likelihood of a normal karyotype. The presence of associated anomalies reduces the survival to 50%, and when accompanied by significant oligohydramnios, the mortality is 100%.

Abnormalities, Multiple↗
PubMed1992

Three-dimensional ultrasound of fetal surface features.

This paper presents preliminary results of techniques which permit acquisition and display of three-dimensional fetal anatomy using ultrasound image data collected as two-dimensional planar images with commercially available equipment. A precision translational stage was used which permitted the transducer position and orientation in the volume to be accurately determined. Ultrasound video image data were digitized into a personal computer together with transducer position and orientation information. All image and position data were subsequently transferred to a graphics workstation. Gray-scale ultrasound data were three-dimensionally filtered, thresholded and analyzed using maximum intensity, variable transparency and surface rendering techniques to evaluate the fetal surface. Images of arbitrary orientation were displayed interactively on a graphics workstation. Our results demonstrate the potential of three-dimensional ultrasound as a technique for visualization of fetal surfaces, extremities and internal anatomy. Three-dimensional ultrasound offers potential advantages over existing diagnostic methods since it is non-invasive and offers interactive review and viewing optimization after fetal scanning.

Journal Article↗
PubMed1992

Second-trimester echogenic bowel and chromosomal abnormalities.

OBJECTIVE: Our objective was to examine the outcomes of pregnancies in which echogenic bowel was detected in the second trimester. STUDY DESIGN: Twenty-two cases with a prospective diagnosis of echogenic bowel were reviewed. Karyotypic studies were performed in 19 cases, and 17 families had deoxyribonucleic acid-based risk assessment for cystic fibrosis. The echogenicity of the bowel was retrospectively reviewed and graded as mild or bright. RESULTS: Five cases of trisomy 21 and one case of trisomy 18 were detected; four of these had other ultrasonographic abnormalities. Twenty-seven percent of fetuses with echogenic bowel were aneuploid. Risk was greatest for cases with brightly echogenic bowel. No cystic fibrosis mutations were detected. The diagnosis of echogenic bowel was reproducible. CONCLUSION: Brightly echogenic bowel in the second trimester was found to be associated with a significant risk of fetal aneuploidy.

Chromosome Aberrations↗
PubMed1992

Simple adnexal cysts: the natural history in postmenopausal women.

Transabdominal and transvaginal ultrasound (US) examinations were performed in 184 asymptomatic postmenopausal volunteers to determine prospectively (a) the frequency and natural history of simple adnexal cysts in healthy postmenopausal women and (b) the relationship between cyst activity and both hormone replacement and length of time since menopause. Eighty-three simple adnexal cysts were found in 52 women. Thirty-two of 184 women (17%) had 37 cysts identified at initial examination; 46 new cysts appeared in 31 women (11 of whom previously had cysts). Forty-nine women with 72 cysts were reevaluated with subsequent US scanning over a period of 3-23 months. Thirty-eight of the 72 cysts (53%) disappeared completely, 20 (28%) remained constant in size, eight (11%) enlarged by 3 mm or more, two (3%) decreased in size by 3 mm or more, and four (6%) both increased and decreased in size on repeated examinations. No statistical relationship was found between presence of cysts or cyst activity with respect to the type of hormone replacement or length of time since menopause.

Adnexal Diseases↗
PubMed1992

Spontaneous improvement of intrathoracic masses diagnosed in utero.

The diagnosis and pregnancy outcome for 14 fetuses with sonographically detected chest masses were reviewed retrospectively. Six lesions became smaller or less apparent during gestation or resolved between antenatal and perinatal imaging studies; these included all three types of cystic adenomatoid malformation (CAM), as well as one case of pulmonary sequestration (PS). This information is extremely important in counseling patients in the second trimester who are considering termination of pregnancy. The poor prognosis traditionally assigned to type II and type III CAM needs changing to reflect the phenomenon of improvement with excellent long-term outcomes. Sonographic indicators of poor outcome were polyhydramnios, hydrops or marked cardiac deviation.

Adult↗
PubMed1992

Linear echoes in the fetal cisterna magna.

Linear echoes are seen in the fetal cisterna magna, (CM) on obstetrical sonography. These echoes often are paired, joining as they descend toward the base of the posterior fossa. Histologic correlation suggests that these echoes are most consistent with dural folds, which likely represent the inferior attachment of the falx cerebelli. A prospective series of 322 prenatal studies was performed in which the sonographer was asked to look for the linear echoes in the cisterna magna and image them. Linear echoes were identified in 84% of all fetuses studied. Identification of these echoes was dependent on CM size, in that they were seen less commonly when the CM was less than 3 mm in diameter. However, their identification was not dependent on gestational age. In addition, 18 fetuses with Dandy Walker cyst or Dandy Walker variant were evaluated and in 16 linear echoes were not seen. We conclude that recognition of normal anatomy within the fetal brain, specifically the fetal CM, is helpful for identifying abnormalities in the size of the CM, whether large or small.

Cisterna Magna↗
PubMed1992

3-dimensional sonographic analysis based on color flow Doppler and gray scale image data: a preliminary report.

This paper presents preliminary results of a technique that permits acquisition and display of three-dimensional (3D) anatomy using data collected from color flow Doppler and gray scale image sonography. 3D sonographic image data were acquired as two-dimensional planar images with commercially available equipment. A translational stage permitted the transducer position and orientation to be determined. Color flow sonographic video image data were digitized into a PC-AT computer along with transducer position and orientation information. Color flow velocity and gray scale data were separated, 3D filtered, and thresholded. A surface rendering program was used to define the vessel blood-lumen interface. Planar slices of arbitrary orientation and volume rendered images were displayed interactively on a graphics workstation. The technique was demonstrated in a lamb kidney in vitro and for the carotid artery at the bifurcation in vivo. Our results demonstrate the potential of 3D sonography as a technique for visualization of anatomy. Color flow data offer direct access to the vascular system, facilitating 3D analysis and display. 3D sonography offers potential advantages over existing diagnostic studies in that it is noninvasive, requires no intravenous contrast material, offers arbitrary plane extraction and review after the patient has completed the examination, and permits vascular anatomy to be visualized clearly via rendered images.

Animals↗
PubMed1992

Sonographic evaluation of pregnancies with maternal varicella infection.

We reviewed 37 cases of mothers who had varicella-zoster virus (VZV) infection during early pregnancy, who subsequently underwent fetal sonography in the 13th to 37th week of gestation. Of the five infants later shown to have congenital varicella infection at postnatal examination (1 case) or autopsy (4 cases), all showed ultrasonographic abnormalities suggesting infection, and all died by 4 months of age. None of the 32 unaffected infants demonstrated in utero ultrasonographic abnormalities. No statements about relative risk of being affected by the virus can be made from this data.

Chickenpox↗
PubMed1992

Abnormal spinal curvature in the fetus.

We reviewed 20 cases of sonographically detected abnormal fetal spinal curvature to help determine the significance of this finding. Both marked (13 cases) and mild (7 cases) curves were diagnosed sonographically. Sonography showed associated anomalies in 19 fetuses, including neural tube and ventral wall defects. Outcomes were poor, with only three infants surviving. Isolated scoliosis was identified prenatally in one neurologically normal infant with hemivertebrae. We conclude that abnormal spinal curvature in the fetus is a significant finding, whether mild or severe. Even as an isolated finding, it is significant, as prenatal detection assists postnatal management.

Female↗
PubMed1991

Prevalence of simple adnexal cysts in postmenopausal women.

This prospective study was performed with ultrasound (US) to determine the prevalence of unilocular, nonseptated adnexal cysts ("simple cysts") in healthy postmenopausal women and the relationship between cyst occurrence and both hormone replacement and length of time since onset of menopause. Transabdominal and transvaginal US were performed on 149 volunteers aged 50 years or older. Patients were classified according to hormone regimens (no hormones, unopposed estrogen, continuous daily estrogen and progesterone, and sequential estrogen and progesterone) and time since onset of menopause (less than 5 years, 5-10 years, and greater than 10 years). Simple adnexal cysts were found in 22 women with the aid of transvaginal and/or transabdominal US, yielding a relative frequency of 14.8% +/- 5.7% and a prevalence of 14,800 patients with cysts per 100,000 patients. No statistical relationship was found between cyst frequency and type of hormone replacement or length of time since onset of menopause.

Aged↗
PubMed1991

Endometrial thickness after menopause: effect of hormone replacement.

Ultrasound (US) images of the pelvis were evaluated in 112 asymptomatic postmenopausal women to investigate the normal range of endometrial thickness (double-layer measurement) and the effect of hormone replacement on these measurements. Twenty-one patients (19%) had endometrial thickness greater than 0.8 cm. One patient, with an endometrial thickness of 2.5 cm, had endometrial carcinoma. Consideration of the known actions of estrogen and progestogen on the endometrium led the authors to believe that the clinical significance of an endometrium measuring more than 0.8 cm depends on the patient's hormonal status. Among asymptomatic postmenopausal women with an endometrial thickness between 0.8 and 1.5 cm, those receiving unopposed estrogen or continuous estrogen and progestogen need to undergo dilatation and curettage (D&C) or biopsy and those receiving no hormones or receiving sequential estrogen and progestogen should be encouraged to undergo D&C or biopsy. If a patient in one of the latter two groups is unwilling to undergo an invasive procedure, then US examination at 3-month intervals is acceptable. Any patient with endometrial thickness of at least 1.5 cm should undergo histologic diagnosis, regardless of symptoms or hormone status.

Biopsy↗