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Biomedical subjects

P W Callen

Publications and source records attributed to P W Callen.

At least 91 records · Page 5Linked to original sources
PubMed1985

Pelvimetry by magnetic resonance imaging.

Sagittal and transverse multisection magnetic resonance imaging (MRI) in 10 patients was used to obtain dimensions of the maternal pelvis, determine fetal position, and examine maternal and fetal soft tissues. Dimensions were measured with less than 1% instrument error, and bony landmarks were readily identified. MR pelvimetry is an accurate technique for obtaining traditional pelvimetric measurements without exposure to ionizing radiation. These techniques can be further used to investigate soft-tissue dystocia and obstructed labor.

Dystocia↗
PubMed1985

Magnetic resonance imaging of fetal anomalies in utero: early experience.

Five cases of fetal dysmorphology were examined with high-resolution sonography and magnetic resonance imaging (MRI). Postpartum confirmation was available in all cases. The high contrast resolution of MRI resulted in clear depiction of the abnormalities, particularly dilated fluid-filled structures, whereas the real-time capability and spatial resolution of sonography permitted better appreciation of anatomic detail. While sonography will remain the primary imaging method for pregnancy, MRI appears to be a promising complementary technique in difficult cases.

Female↗
PubMed1985

Minimal fetal renal pyelectasis.

To assess the possible relationship between the degree of maternal hydration and the sonographic identification of minimal fetal renal pyelectasis, a prospective study was performed in which fetuses demonstrating mild dilation of the renal pelvis (maximum diameter ranging from 3 to 11 mm) were reexamined after the mothers refrained from oral intake for 12 hours. Complete or almost complete resolution of the pyelectasis occurred in only four of 17 kidneys (23.5 per cent) while the remaining fetal kidneys demonstrated little or no change in the degree of pyelectasis following maternal dehydration. This observation, as well as previous experimental research, suggests that the state of maternal oral hydration is not a major cause of minimal fetal pyelectasis. Additionally, the observation of fetal pyelectasis measuring at least 3 mm in greatest dimension is common, occurring in approximately 18 per cent of fetuses older than 24 menstrual weeks.

Dehydration↗
PubMed1985

A specular reflection arising from the ventricular wall: a potential pitfall in the diagnosis of germinal matrix hemorrhage.

Reflection artifacts may complicate the diagnosis of intracranial hemorrhage in preterm neonates. A linear focus of bright echoes in the region of the germinal matrix at or anterior to the caudothalamic grooves, often seen on parasagittal scans, may be mistaken for a germinal matrix hemorrhage but is actually a reflection of the ultrasound beam at the wall of the lateral ventricle. Cranial sonograms of 100 preterm infants were retrospectively analyzed and categorized with regard to presence and size of specular reflection. Eight cases demonstrated a bright echogenic focus; seven of these potentially could have been mistaken for hemorrhages.

Cerebral Hemorrhage↗
PubMed1985

Sonographic evaluation of ectopic pregnancy.

To assess sonographic findings in the evaluation for ectopic pregnancy, all women referred over a two-year period were prospectively evaluated. The incidence of intrauterine as well as adnexal findings was assessed in an attempt to optimize sonographic evaluation. Visualization of a double decidual sac sign (DDSS) within the uterus provided an accurate means of confirming an intrauterine pregnancy (IUP) prior to embryo visualization. Forty-two of 130 women with IUP were diagnosable only by the DDSS. As a screening test for ectopic pregnancy, sonographic documentation of an IUP provided the only convincing evidence for the absence of an ectopic gestation. Any woman clinically at risk for ectopic pregnancy whose sonogram did not confirm the presence of an intrauterine pregnancy was at relatively high risk (43 per cent) for having an ectopic gestation. Characterization of adnexal findings increased the level of risk for ectopic pregnancy in these women to 70-100 per cent. However, 20 per cent of women with a surgically confirmed ectopic pregnancy had normal adnexal findings.

Female↗
PubMed1985

Umbilical vein thrombosis: sonographic detection in utero.

Umbilical vein thrombosis is associated with a high perinatal mortality and is seen most often with compression, torsion, stricture, or hematoma of the umbilical cord. Three cases of umbilical vein thrombosis detected on obstetrical ultrasound scans performed for suspected fetal demise are presented.

Adult↗
PubMed1985

Sonography, a complementary examination to alpha-fetoprotein testing for fetal neural tube defects.

Neural tube defects (NTDs) are among the most common congenital anomalies in the United States, with an estimated prevalence of 16 per 10,000 births. The measurement of amniotic fluid alpha-fetoprotein (AF-AFP) concentration has been used to detect NTDs since the early 1970s. When the AF-AFP concentration is elevated, ultrasonography is commonly used to confirm the presence of a NTD. In this study, patient charts, amniocentesis records, and ultrasound reports from a three-year period were reviewed. The 97 fetuses identified as being at high risk for NTDs were divided into four groups: those with high AF-AFP concentrations (Groups 1 and 2, with from 3 to 5 standard deviations (SD) above the mean and with more than 5 SD above the mean, respectively): those referred from other institutions because of suspicious sonographic results (Group 3); and those at risk because of a previous sibling with a NTD (Group 4). Ultrasonography was 100 per cent sensitive and 100 per cent specific in diagnosing NTDs. Thus, in pregnancies with an elevated AF-AFP concentration, ultrasonography can reliably identify normal fetuses as well as differentiate between those with NTDs and those with other congenital anomalies. Also, since AF-AFP concentrations decline after 20 weeks' gestation, ultrasonography may be a better test than a repeat amniocentesis in equivocal cases of AF-AFP elevation.

Adult↗
PubMed1985

Ultrasound evaluation of the normal fetal upper airway and esophagus.

Because congenital anomalies of the fetal neck may alter the normal anatomy of the upper airway, a prospective evaluation of the fetal trachea, hypopharynx, and esophagus was undertaken in 50 consecutive fetuses of 18 to 38 menstrual weeks. The cervical trachea was visualized in 47 of 50 fetuses (94 per cent) and had an average internal diameter of 2.6 mm with a range of 2 to 4 mm. The average diameter of the hypopharynx was 5.5 mm on parasagittal section (range 4-8 mm) and 7.1 mm when imaged in the coronal plane (range 4-10 mm). The configuration of the fetal hypopharynx and larynx varied with fetal respiration and swallowing in a characteristic manner. In no case was a persistent fluid collection observed in the region of the cervical esophagus, suggesting that the fetal esophagus is collapsed in the resting state.

Esophagus↗
PubMed1985

Placental thickness.

The sonograms of 200 randomly selected singleton pregnancies were reviewed. Placental thickness was measured and correlated with menstrual age. The placenta was demonstrated to increase in thickness with advancing menstrual age. At no stage of pregnancy was the normal placenta greater than 4 cm in thickness. Potential pitfalls in measuring placental thickness are addressed, as well as potential causes of aberrations in placental thickness.

Anthropometry↗
PubMed1984

Investigation of nonimmune hydrops fetalis.

Fifty pregnancies complicated by fetal ascites and generalized edema are reviewed and their prenatal findings, obstetric management, and fetal outcome are discussed. From the myriad of maternal, fetal, and placental problems which are known to cause nonimmune hydrops fetalis, many different causes of the disorder could be identified in 84% of all patients studied by extensive prenatal and postnatal workup. Therefore, in only 16% of the cases was the nonimmune hydrops fetalis labeled "idiopathic." The most common demonstrable causes of the disorder in this series were cardiac anomalies, followed by chromosomal disorders, congenital malformations, alpha-thalassemia, and the twin-twin transfusion syndrome. A systematic approach to the prenatal diagnostic workup of nonimmune hydrops fetalis is outlined, starting with the least invasive techniques (ultrasound, echocardiography, complete blood count, Kleihauer-Betke analysis, TORCH testing, and so forth) followed by more invasive techniques (amniocentesis and fetoscopy). Although the detection and prognostic evaluation of nonimmune hydrops fetalis are greatly improved by applying these techniques, the overall prognosis for most fetuses with nonimmune hydrops fetalis is still very poor, and only a few conditions causing the disorder, such as prenatally detected cardiac arrhythmias or selected cases of urinary tract obstruction, are amenable to treatment in utero.

Ascites↗
PubMed1984

Ultrasonographic determination of qualitative amniotic fluid volume in intrauterine growth retardation: reassessment of the 1 cm rule.

To assess the relative diagnostic efficacy of the "1 cm sign" for qualitative amniotic fluid volume determination in the prenatal evaluation of intrauterine growth retardation, 125 pregnancies resulting in small-for-gestational age infants were studied in a retrospective fashion. Qualitative amniotic fluid volume was designated as normal if at least one pocket of amniotic fluid measuring 1 cm in broadest diameter was identified. Of the 125 pregnancies with delivery of small-for-gestational age infants, only five would have been correctly predicted prenatally with qualitative amniotic fluid volume used as the sole criterion for intrauterine growth retardation. When this criterion was applied to a defined subset of 52 of these patients with last scans 0 to 15 days prior to delivery, only four cases would have been accurately predicted as having intrauterine growth retardation.

Amniotic Fluid↗
PubMed1984

Management of the fetus with an abdominal wall defect.

Eleven fetuses with omphalocele and two with gastroschisis were diagnosed by prenatal ultrasonographic examination. Intact omphalocele was accurately distinguished from gastroschisis by detection of a membranous sac covering the herniated viscera, by liver protruding from the abdomen, and by the frequent association of major structural anomalies. Gastroschisis was characterized by the absence of these findings and the presence of bowel loops floating freely in the amniotic fluid. Nine of eleven fetuses with omphaloceles had other major malformations and did not survive. Two small omphaloceles and two gastroschises were correctly diagnosed as isolated defects, free from associated anomalies. All four underwent maternal transport and were successfully managed with good outcome. Prenatal ultrasonography allows rational decisions about perinatal management by distinguishing between omphalocele and gastroschisis and by screening for associated anatomic defects. Karyotype analysis should be a part of the prenatal workup. Most isolated defects can be followed and delivered normally near term. Accurate prenatal diagnosis allows maternal transport and in a few cases may alter the timing or mode of delivery.

Adolescent↗
PubMed1984

Management of ventriculomegaly in the fetus.

We studied 24 human fetuses with cerebral ventriculomegaly by serial obstetric ultrasound to define the natural history of fetal ventricular enlargement and to develop a management strategy. In 10 fetuses, ventriculomegaly was associated with other severe anomalies; nine of these families chose to terminate the pregnancy. In three other severely affected fetuses in whom ventriculomegaly was detected serendipitously late in gestation, routine obstetrical management was performed; none survived. Eleven fetuses had ventriculomegaly without associated severe anomalies. Ventriculomegaly remained stable or of moderate severity throughout gestation in nine, resolved gradually in one, and progressed in one who did not have signs of increased intracranial pressure at birth. All of these fetuses were viable; three patients required shunting in the neonatal period, and two others by 5 months of age. Although obstetric ultrasound usually can detect anomalies associated with fetal ventriculomegaly, three fetuses with isolated ventriculomegaly had midline brain malformations that could not be distinguished in utero from hydrocephalus, even in retrospect. Prenatal diagnosis improves perinatal management by allowing counseling, and selective pregnancy termination, or selection of the timing, mode, and place of delivery to optimize outcome. Most fetuses with ventriculomegaly do not require intervention before birth.

Abnormalities, Multiple↗
PubMed1984

Alobar holoprosencephaly: ultrasonographic prenatal diagnosis.

Modern ultrasound imaging devices have increasingly allowed sophisticated prenatal diagnoses of fetal disorders. Embryopathologic and ultrasound findings are reported in five cases of alobar holoprosencephaly that were diagnosed prenatally, two cases as early as 23 menstrual weeks. Specific sonographic findings included a large central cranial fluid collection (a monoventricular cavity lacking ventricular horns and midline structures), a fused thalamus at the floor of this cavity, and characteristic facial features (proboscis, single orbit, single nostril, or severe hypotelorism). Differential diagnosis of the fetus with a large intracranial fluid collection is discussed and illustrated.

Abnormalities, Multiple↗