Training in obstetric sonography for radiology residents and fellows in the United States

OBJECTIVE

The purpose of our study was to assess the current experience of radiology residents and fellows in obstetric sonography.

SUBJECTS AND METHODS

Written surveys were sent to the directors of 206 accredited radiology residency programs and 85 fellowship programs in the United States. The surveys encompassed obstetric sonographic experience during routine working hours and after hours, the level of supervision, the types of scanning performed, and the extent of formal lectures available during training. Additional questions concerned the relative knowledge of laboratory accreditation processes and training of faculty covering obstetric sonography.

RESULTS

Sixty (29%) of 206 accredited radiology residency programs and 24 (28%) of 85 fellowship programs returned surveys. The experience among residency programs was similar, providing fewer than 4 weeks per year of obstetric sonography, usually within their own department of radiology. Residents were more likely to be sent to outside departments for second or third trimester sonography experience. A decrease in scanning assistance was reported for examinations performed after hours, more so for second or third trimester studies. Lecture topics revealed similar deficiencies for residency and fellowship programs.

CONCLUSION

Greater emphasis on the performance of prenatal sonographic examinations may be warranted during formal sonography rotations. Current levels of experience in obstetric sonography may not be providing sufficient experience to allow residents to appropriately manage call cases or for practicing radiologists to provide such services after their training is completed.

The mentor effect in student evaluation

OBJECTIVE

To determine if faculty mentors rate their mentored students higher than do nonmentors, and to ascertain if gender is a factor.

METHODS

All third-year students (n = 101) from academic years 1996-1998, who performed their obstetrics and gynecology clerkship at the Milton S. Hershey Medical Center in the Penn State Geisinger Health System and were evaluated by full-time faculty (n = 18), were included in the study (total observations = 545). Students were rated by faculty on an ordinal scale in five categories. Generalized estimating equation methodology was used to fit proportional odds models for ordinal data to assess whether there were statistically significant mentor or faculty/student gender effects.

RESULTS

Student evaluations from mentors were more likely to have better scores than student evaluations from nonmentoring-faculty for all five categories (all P <.01). The odds ratios (OR) for the mentor effect ranged from 2.1 (95% confidence interval [CI] 1.4, 3.2) for fund of knowledge to 3.2 (95% CI [2.1, 4. 8]) for attitude. For problem-solving and technical skills, male faculty were more likely than female faculty to give male students better scores (problem-solving skills: odds ratio [OR] = 1.7, 95% CI [1.0, 2.7]; technical skills: OR = 2.2, 95% CI [1.1, 4.6]). Mentoring-faculty evaluations were not strongly correlated with the students' objective examination scores.

CONCLUSION

Overall, mentors score their mentored students statistically higher than do nonmentors. Gender differences in evaluation, while present, are less consistent and smaller than the mentor effect.

Diagnosis and differentiation of congenital diaphragmatic hernia from other noncardiac thoracic fetal masses

This retrospective study was designed to evaluate individual sonographic parameters that might help differentiate congenital diaphragmatic hernia (CDH) from other noncardiac thoracic masses such as cystic adenomatoid malformation of the lung (CAML) and congenital lobar emphysema (CLE) prenatally. Twenty-four cases of CDH, CAML, and CLE detected during prenatal ultrasound and documented postnatally (with surgical, autopsy, or radiological proof) were identified through extensive chart and record review. The hard copy gray-scale images were retrospectively reviewed for imaging characteristics that may differentiate the three entities. Additionally, the prospective diagnosis during prenatal ultrasound was also compared with the postnatal diagnosis. The most reliable indicators in our retrospective review included confident visualization of a diaphragmatic defect (92.3/100.0 PPV/NPV, p< or =0.002) and/or localization of the stomach within the chest as well as the presence of severe cardiac deviation (both 92.3/62.5 PPV/NPV, p< or =0.01). Other sonographic indicators (including the presence of cystic areas, side and size of the lesion and the presence of polyhydramnios) offered lower levels of sensitivity and specificity. Prospective diagnosis during real-time assessment was also integral, offering >80% sensitivity and specificity (p< or =0.001). Accurate prenatal diagnosis of CDH is difficult despite the relative frequency of this lesion. The classic triad of a thoracic mass accompanying a displaced heart, absence of a normally positioned fluid-filled stomach and polyhydramnios, although seen with CDH, may not adequately differentiate this entity from other noncardiac fetal thoracic masses. Realtime assessment remains integral to the appropriate diagnosis.

Central hemodynamic effects of oxytocin and interaction with magnesium and pregnancy in the isolated perfused rat heart

OBJECTIVE

Our purpose was to determine the cardiac effects of oxytocin in the isolated perfused rat heart model and to see whether pregnancy or pharmacologic levels of magnesium modifies the hormone's action.

STUDY DESIGN

Hearts were excised from 30 female Sprague-Dawley rats (15 pregnant, 15 nonpregnant) and attached to a Langendorf's apparatus. Heart rate, left ventricular systolic pressure, and contractility were measured. Hearts were exposed serially to 2, 4, and 6 mU/ml concentrations of oxytocin. The experiment was repeated in 15 pregnant animals at a magnesium level of 5 mEq/L.

RESULTS

Hearts from pregnant rats had lower heart rates than did hearts from nonpregnant animals. Oxytocin exposure diminished heart rate but increased left ventricular systolic pressure and contractility in a dose-dependent manner. Pregnancy did not alter this response. Magnesium levels of 5 mEq/L reversed the effects of oxytocin on contractility and left ventricular systolic pressure.

CONCLUSION

Oxytocin is a negative chronotropic and positive inotropic agent in hearts from pregnant and nonpregnant rats. Magnesium reserves the positive inotropic effects of oxytocin.

Effects of maternal smoking on amniotic fluid volume and fetal urine output

The purpose of this study was to assess the effects of maternal smoking on amniotic fluid volume and fetal urine output. Seventeen women (10 smokers and 7 non-smokers) were serially assessed through pregnancy. Smoking status was determined by self-report and carbon monoxide manometry. Amniotic fluid volume was assessed by sonographically measuring the maximum vertical pocket, the amniotic fluid index, and the two dimensions of the largest pockets. The coronal area formula was used to calculate bladder volume at 5-minute intervals for 20 minutes. Urine output was calculated from serial measurements of bladder volume. The mean gestational age of the first session was 26.8 (2.7) weeks, of the second session 32.4 (1.6) weeks, and of the last session 36.9 (2.1) weeks. In the univariate analysis there were no differences between smokers and non-smokers at any of the three visits for gestational age, fetal weight, maximum vertical pocket, amniotic fluid index, two-dimensional maximum pocket, and urine output. In the regression model, while controlling for gestational age, smoking status could not predict significant differences in any parameter. Maternal smoking does not appear to affect either amniotic fluid volume or fetal urine output.

Central hemodynamic effects of recombinant human relaxin in the isolated, perfused rat heart model

OBJECTIVE

To determine the cardiac effects of relaxin in the isolated, perfused rat heart model, and to see if pregnancy modifies the hormone's actions.

METHODS

Hearts were excised from 18 female Sprague-Dawley rats (ten pregnant, eight nonpregnant) and attached to a Langendorff apparatus. Left ventricular systolic pressure, heart rate, and contractility were measured. Hearts were exposed serially to 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 ng/mL concentrations of recombinant human relaxin.

RESULTS

Hearts from pregnant rats had lower heart rates than those from nonpregnant animals. Relaxin increased heart rate, left ventricular systolic pressure, and contractility in a dose-dependent fashion. Pregnancy did not modify this response.

CONCLUSION

Recombinant human relaxin is a potent inotropic and chronotropic agent. The effects coupled with the physiologic increase of relaxin during human pregnancy indicate that relaxin may be involved in the cardiovascular changes of pregnancy.

Myocardial infarction and coronary artery dissection in pregnancy

Myocardial infarction associated with pregnancy is a relatively rare event, usually related to maternal risk factors for ischemic heart disease such as hypertension and diabetes mellitus. Coronary artery dissection represents an even more uncommon event and generally occurs in peripartum women without predisposing risk factors. A 31-year-old patient's postpartum course was complicated by the development of probable acute fatty liver of pregnancy followed by myocardial infarction and coronary artery dissection. The acute fatty liver of pregnancy and the cardiac event in our patient may both be vasospastic events related to vascular hypersensitivity.

Pelvic magnetic resonance imaging in the evaluation of uterine torsion

BACKGROUND

Uterine torsion is defined as the rotation of more than 45 degrees around the long axis of the uterus. An uncommon but potentially fatal event, uterine torsion is rarely diagnosed until the time of surgery. With magnetic resonance imaging (MRI), however, an accurate diagnosis of uterine torsion may now be made preoperatively.

CASE

We describe a patient with uterine torsion in whom the correct diagnosis was made prenatally with the use of MRI, by the demonstration of an X-shaped configuration of the upper vagina.

CONCLUSION

Distinctive features suggestive of uterine torsion were demonstrated by MRI and enabled an accurate preoperative diagnosis. To our knowledge, this is the first reported case of uterine torsion diagnosed on MRI.

Prenatal diagnosis and management of massive bilateral axillary cystic lymphangioma

BACKGROUND

Fetal lymphangiomas can occur in many different anatomic locations, including the most commonly seen nuchal cystic hygroma.

CASE

A fetus at 18 weeks' gestation was found to have a massive right axillary hygroma. The fetal karyotype was normal. Serial ultrasound examinations indicated progressive enlargement, but no hydrops. At 32 weeks' gestation, a left axillary hygroma was also diagnosed. The patient underwent cesarean delivery.

CONCLUSION

Prenatal diagnosis of nuchal cystic hygromas has a high association with karyotypic abnormalities, hydrops, and fetal demise; however, this association may not apply to cystic lymphangiomas at other locations.

Nonimmune hydrops fetalis secondary to premature closure of the foramen ovale

Premature closure of the foramen ovale is a rare cardiac anomaly. Severe right-sided heart failure accounts for the hepatomegaly, ascites, pleural and pericardial effusions, and generalized edema of these hydropic fetuses. Premature closure of the foramen ovale should be a part of the differential diagnosis when unexplained fetal hydrops is encountered.

Prenatal diagnosis of renal agenesis in a twin gestation

Bilateral renal agenesis is a lethal congenital anomaly. It appears to be transmitted in a polygenic pattern. The prenatal ultrasound findings consist of severe oligohydramnios, absence of the fetal bladder, and failure to identify fetal kidneys. Twin gestations with renal agenesis have been described in the paediatric literature. We detail a case of a patient with two prior affected pregnancies with bilateral renal agenesis. Her latest pregnancy was diagnosed prenatally, with one fetus with bilateral and the other fetus with unilateral renal agenesis. The ultrasound findings should be differentiated from the stuck twin phenomenon.

Nonimmune hydrops and hydrocephalus secondary to fetal intracranial hemorrhage

Our case demonstrates that nonimmune hydrops and hydrocephalus may be associated by the common pathway of intracranial hemorrhage and the development of anemia. The anemia apparently resulted in cardiomegaly with pericardial effusion and ascites as well as marked extramedullary hematopoiesis.

Rapid purification of calmodulin and S-100 protein by affinity chromatography with melittin immobilized to sepharose

Melittin-Sepharose was prepared for Ca2+-dependent affinity chromatography of calmodulin and S-100 protein. This matrix exhibits extremely high capacity (approximately 10 mg calmodulin/ml gel), low nonspecific binding, and excellent recovery (greater than 90%) under optimal conditions. Recovery of calmodulin from melittin-Sepharose was related to the degree of saturation of column capacity with lower yields when only partial saturation was achieved. Large-scale, simultaneous purification of calmodulin and S-100 protein from brain was carried out using selective adsorption to organomercurial agarose followed by melittin-Sepharose chromatography; yields were 250-300 mg of calmodulin and 200-300 mg of S-100 per kg tissue. Calmodulin also was purified in a single step from bovine testis supernatant using melittin-Sepharose in yields comparable to those from brain.