Biomedical subjects
Publications and source records attributed to P W Callen.
The in utero sonographic diagnoses of 13 clubbed feet in eight fetuses are reported, and five representative cases are described in detail. The sonographic findings and clinical features of fetal clubfoot are discussed. The prenatal sonographic detection of clubfoot should alert the sonographer to search for other congenital anomalies associated with syndromes involving clubfoot.
Seven cases of heterozygous achondroplasia were examined in utero. Although the head shape and growth were normal, the initially normal femur length showed a decrease in growth and fell below the lower 99 per cent confidence limit in all cases. The time of presentation of achondroplasia varied between 21 and 27 gestational weeks. This study suggests that the diagnosis of achondroplasia can be reasonably made when the femur is abnormally short. When the femoral length is appropriate prior to 30 weeks, more caution should be taken in interpretation. Because of the variability in presentation, the fetus could be normal or still could be affected.
A sonolucent band associated with the fetal abdominal wall is frequently observed in the normal obstetrical ultrasound examination. This band has been labeled pseudoascites because it may closely mimic intraperitoneal fluid. Fifty-three consecutive fetuses were examined sonographically; pseudoascites was evident in 45 fetuses. Sonographic anatomic observations identify pseudoascites as the fetal abdominal wall musculature. The anatomic description of pseudoascites, as well as the difference between pseudoascites and fetal intraperitoneal fluid, are discussed.
The sonograms from 15 patients who underwent 40 intrauterine transfusions at the University of California San Francisco School of Medicine, between December 1981 and December 1984 were retrospectively reviewed. The authors found that 12 to 14 ml of fluid were easily seen in 18- to 20-menstrual-week fetuses and that 30 to 40 ml were seen in fetuses at greater than or equal to 30 menstrual weeks. Since the study was retrospective, the absolute minimum of detectable fetal intraperitoneal fluid was not recorded for each fetus. The above represent amounts that were consistently documented during each intrauterine transfusion. In order to gain information about the minimum detectable fetal intraperitoneal fluid, two fetuses undergoing intraperitoneal transfusions were studied prospectively. The minimum fetal intraperitoneal fluid volumes observed were 10 ml in a 22-week fetus and 15 ml in a 26-week fetus.
Sonographic measurement of the occipital, parietal, and frontal cerebral cortical mantle in ten neonates and ten fetuses with moderate to marked hydrocephalus was performed. In 11 of 14 (78.5 per cent) of the neonatal scans and in 10 of 12 (83 per cent) of the fetal scans, the occipital cortical mantle was less than that of the frontal cortical mantle. This difference varied from 1 to 16 mm. While prognostic data regarding compression of the cerebral mantle from ventricular dilatation exist, they are based upon measurements of the frontal-parietal and not the occipital mantle. Because of the difference observed, if these data are to be used in management, the comparable cerebral cortical mantle should be measured.
Amniotic band syndrome causes a variety of fetal malformations involving the limbs, craniofacial region, and trunk. Six prenatally diagnosed cases of amniotic band syndrome are discussed. The diagnosis was based on sonographic visualization of either amniotic sheets or bands associated with fetal deformation or deformities in nonembryologic distributions known to characterize the amniotic band syndrome. Seven additional cases are considered in which an aberrant sheet of tissue with a free edge was visualized within the amniotic cavity but no restriction of fetal motion or subsequent deformity was demonstrated.
Selecting appropriate management for the fetus with bilateral congenital hydronephrosis depends on our ability to accurately assess the severity of existing renal damage and to predict the potential for recovery of renal and pulmonary function if the obstruction is relieved. We reviewed our experience with 20 fetuses with congenital bilateral hydronephrosis to determine the prognostic value of various criteria used to assess functional potential, including temporary catheter exteriorization to measure fetal urine output and composition. Based on autopsy, biopsy, or clinical outcome, ten fetuses were classified retrospectively as "poor function," and ten fetuses as "good function." The good function group could be distinguished from the poor function group by the following criteria: Amniotic fluid (AF) status at presentation (P less than .001), ultrasound appearance of the fetal kidneys (P less than .05), fetal urine sodium and chloride concentration and osmolarity (P less than .001), and hourly urine output (P less than .02), but not by fetal urine iothalamate excretion or potassium and creatinine concentrations (P greater than .05). Based on these results, we have identified prognostic criteria that accurately identify the fetus with "good function" from the fetus with "poor function." We also reviewed the clinical management of our last 12 unreported cases. Ten fetuses had undergone diagnostic catheter placement and in utero renal function testing. This led to placement of a therapeutic indwelling catheter-shunt in seven fetuses (three required multiple shunts) and a suprapubic vesicostomy in another. Catheter related complications, including three cases of chorioamnionitis, emphasize the need for better methods of in utero decompression in selected cases. Our ability to select appropriate management has improved markedly.
Is gastroschisis embryologically distinct from omphalocele or simply a ruptured small omphalocele (hernia of the umbilical cord)? Serial sonographic imaging of a fetus with a small omphalocele at 27 weeks gestation has now provided the "missing link" in the pathogenesis of gastroschisis by documenting in utero rupture resulting in a gastroschisis.
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.
We studied the natural history and pathophysiology of congenital cystic adenomatoid malformation (CCAM) detected prenatally by ultrasound in twelve fetuses. Two types of fetal CCAM can be distinguished by gross anatomy, ultrasound findings, and prognosis. Microcystic lesions are usually associated with fetal hydrops and have a poor prognosis (five cases with one survivor). Antenatal diagnosis, maternal transport, and immediate thoracotomy after birth allowed the first reported survival of a newborn with a large microcystic CCAM. Macrocystic lesions are not usually associated with hydrops and have a favorable prognosis (five of seven survived). We conclude that fetuses with hydrops are at high risk for fetal or neonatal demise without intervention. Fetuses with CCAM but without hydrops have a good chance for survival with maternal transport, planned delivery, and immediate neonatal resuscitation and surgery.
Eleven patients whose pregnancies were at 34-36 weeks of gestational development underwent magnetic resonance (MR) imaging. Images of the maternal pelvis were assessed for anatomical changes of pregnancy in comparison with MR images of five non-pregnant volunteers. The relationship of the fetal presenting part to the internal os of the cervix was seen in all patients. Effacement of the cervix was identified when present. The maternal spine demonstrated disk abnormalities in nine patients. Changes in venous flow patterns were readily identified in all patients. The inferior vena cava was flattened or obliterated, a high signal was present in the iliac vessels (TE 56), and large collateral vessels were present.
Nine patients who were 34-36 weeks pregnant underwent magnetic resonance (MR) imaging. Sagittal images using spin echo technique (TR 2.0 sec, TE 28 msec) were optimal for delineating fetal anatomy. The fetal cardiovascular, pulmonary, and central nervous systems were depicted in all cases. The heart and major vessels were readily seen due to the natural contrast of flowing blood. The intensity of the fluid-filled lungs greatly increased with a longer TR or TE, delimiting thorax from liver. The brain was relatively featureless due to the lack of gray-white matter differentiation. The umbilical cord within the amniotic fluid and its insertion into the placenta and fetus was identified in all cases. MR is a new modality for fetal imaging that offers tissue-characterization information that complements the superior anatomic detail of ultrasound scanning.
The distal femoral epiphyseal secondary ossification center (DFE), which can be reliably identified and measured sonographically, may assist the sonologist in predicting third-trimester menstrual age. Between 28 and 35 menstrual weeks, the percentage of fetuses with a DFE progressively increases. Although the mean age at DFE appearance is approximately 32-33 menstrual weeks, the DFE may be seen as early as 29 menstrual weeks. Nevertheless, the age of a fetus without an identifiable DFE is most likely less than or equal to 34 menstrual weeks. Measurements of the DFE show that its size increases linearly: the menstrual age of a fetus whose DFE measures greater than or equal to 7mm is most likely greater than or equal to 37 weeks.
A total of 66 twin pregnancies was studied antenatally with ultrasound, followed up clinically, and the placentae examined pathologically to determine if, solely on the basis of antenatal sonography, an accurate assessment of amnionicity and chorionicity could be made. Sonographic features noted included number of placental sites, whether a membrane separating the fetuses could be visualized, fetal position and amount of amniotic fluid, and in some cases fetal positioning vis-a-vis each other and the uterine wall. Documentation of two placental sites confirms the presence of a dichorionic and, therefore, a diamniotic pregnancy. Documentation of a membrane separating the fetuses confirms the presence of a diamniotic pregnancy; lack of visualization of a separating membrane does not reliably predict, but does suggest, a monoamniotic pregnancy. Other features frequently assist in prediction of amnionicity, chorionicity, and zygosity; the most helpful of these was the "stuck twin" sign, in which one twin moved freely but the other remained in a fixed position adjacent to the sidewall of the uterus despite changes in maternal positioning, indicating the presence of a nonvisualized membrane. Presence of absence of entanglement or intermingling of fetal parts or umbilical cords may also be helpful. In the absence of such sonographic features, antenatal sonographic diagnosis of a monoamniotic pregnancy cannot be made reliably.
Eleven high risk fetuses between 32 and 37 menstrual weeks gestational age were examined by magnetic resonance (MR) imaging. Serial obstetrical sonograms, birth weights, and serial postnatal examinations were obtained in all subjects. Sagittal MR spin echo images obtained using TR = 0.5 sec and TE = 28 msec were useful for assessing subcutaneous fat. Prospective estimates of fetal fat stores correlated with neonatal outcome better than sonographic measurements of fetal growth parameters or actual birth weight. MR appears to be a safe and useful technique that offers information complementary to obstetrical sonography when IUGR is suspected.
We attempted to use hand-held, high-resolution breast sonography to localize for biopsy 11 solid, nonpalpable lesions detected by mammography. Using sonography, we identified and localized only one of four lesions presenting as poorly defined masses and only one of seven lesions presenting as clusters of tiny calcifications. This 18% rate of success is too low to justify the use of sonography for all patients undergoing needle localization. Mammography remains the procedure of choice for localizing solid, nonpalpable breast masses and clustered calcifications.
To further elucidate antenatal sonographic features of fetal urethral obstruction and attempt to determine which features might predict subsequent outcome, 40 in utero cases were reviewed. All fetuses had dilated urinary bladders and/or thickened bladder walls; in 47.5% of fetuses a dilated posterior urethra was seen. Only 15 fetuses (37.5%) survived the neonatal period. Survivors tended to present later in gestation than nonsurvivors. Poor prognostic indicators included oligohydramnios (20 of 21 subsequently died), absence of caliectasis (20 of 24 died), a large amount of urine ascites (five of six died), and dystrophic bladder wall or peritoneal calcification (five of five subsequently died). Conversely, 14 of 19 (74%) fetuses without definite oligohydramnios survived the neonatal period.
On the basis of both experimental and clinical studies it is not clear whether left, right, or biventricular heart failure are necessary for the formation of pleural effusions. In order to study the relationship of pulmonary hemodynamics and the presence of pleural effusions in patients with congestive heart failure, we prospectively evaluated 37 patients admitted to the coronary care unit with congestive heart failure secondary to ischemic heart disease or a cardiomyopathy. We used real-time ultrasonography to document the presence of pleural effusions. We found that 19 of the 37 patients with heart failure had pleural effusions. Mean pulmonary artery wedge pressure was 24.1 +/- 1.3 mmHg (SE) in the 19 patients with pleural effusions versus 17.2 +/- 1.5 mmHg (SE) (p less than 0.001) in the 18 patients without pleural effusions. Pulmonary artery pressure was also higher in patients with pleural effusions with a mean value of 38.0 +/- 1.5 mmHg (SE) versus 30.7 +/- 2.1 mmHg (SE) (p less than 0.05) in the patients without pleural effusions. In contrast, mean right atrial pressure was not different between patients with pleural effusions (12.6 +/- 1.5 mmHg) (SE) versus those without pleural effusions (9.8 +/- 1.0 mmHg) (SE) (p = NS). In addition, there was no difference in cardiac output, pulmonary vascular resistance, or total protein concentrations between patients with and without pleural effusions. We conclude that, in patients with congestive heart failure, an elevated left atrial pressure is closely correlated with the presence of pleural effusions, while concurrent elevation of right atrial pressure is not associated with the presence of pleural effusions.