Sonography of placental abnormalities and oligohydramnios in women with elevated alpha-fetoprotein levels: comparison with control subjects

To evaluate the relationship of placental and amniotic fluid findings to elevated maternal serum alpha-fetoprotein (MS-AFP) levels, we compared sonograms made between 18 and 24 weeks gestational age in 76 women with elevated MS-AFP levels with sonograms of a control group. Patients with fetal malformations, incorrect dates, twins, or lack of follow-up were excluded. Overall, 27 (36%) of 76 patients with elevated MS-AFP levels had placental or amniotic fluid abnormalities compared with only three (3%) of 87 control subjects. Significant differences (p less than .01) were noted in the frequency of periplacental hemorrhage (9% vs 0%), intraplacental sonolucencies greater than or equal to 1.5 cm in diameter (18% vs 3%) and moderate or severe oligohydramnios (17% vs 0%). More patients with elevated MS-AFP levels had placenta previa (4%) or placental thickness greater than or equal to 3.5 cm (12%) than did those in the control group (1% and 5%, respectively), although these differences did not reach statistical significance. Seven (26%) of the 27 patients had more than one abnormality. We conclude that placental and/or amniotic fluid abnormalities are frequently shown on sonograms in women who are examined because of elevated MS-AFP levels.     

Detection of fetal central nervous system anomalies: a practical level of effort for a routine sonogram

To evaluate the efficacy of examining the lateral ventricular atrium, cisterna magna, and cavum septi pellucidi as a means of ascertaining that the development of the fetal central nervous system (CNS) is normal, a retrospective evaluation of the sonograms of 112 fetuses (15-39 weeks gestational age) with sonographically diagnosed CNS anomalies was performed. Malformations included in the study were diverse. The lateral ventricular atrium was enlarged (greater than 10 mm) in 99 (88%) fetuses. Of the remaining 13 fetuses, seven had an abnormal-sized cisterna magna (less than 2 mm or greater than 11 mm). These two measurements alone could be used to identify the presence of a CNS abnormality in 95%. Three of the six remaining fetuses exhibited gross abnormalities easily seen on the standard axial images obtained for biparietal diameter measurement. Although the cavum septi pellucidi was absent in a number of cases, its absence did not enhance sensitivity in the cohort examined. Prospective examination of 130 consecutive normal fetuses (15-40 weeks gestational age) was also performed. When specifically sought, the ventricular atrium was identifiable and measurable 99% of the time; the cisterna magna, 90% of the time; and the cavum septi pellucidi, 95% of the time. Because major CNS anomalies are uncommon and these measurements afford high sensitivity, an extremely low probability (0.005%) of abnormal brain or spinal cord development can be predicted if a normal-sized lateral ventricular atrium and cisterna magna are present. These results should not be construed as a license to underexamine fetuses for malformations. Rather, these measurements should serve as simple positive steps to assist in a difficult task.     

Polyhydramnios associated with fetal limb abnormalities

Four cases of fetal dwarfism and one case of extremity shortening with limb reduction abnormalities associated with polyhydramnios are presented. In one case, the diagnosis of camptomelic dwarfism associated with polyhydramnios was missed on sonography because no extremity measurements were obtained. Severe fetal limb anomalities were prospectively diagnosed in two patients with polyhydramnios by sonographic measurement of fetal limb lengths. The development of polyhydramnios was observed in two additional cases of fetal dwarfism. These five cases are presented to emphasize the clinical significance of recognizing the relationship between polyhydramnios and fetal dwarfism.     

Placental abruption and placental hemorrhage: correlation of sonographic findings with fetal outcome

Sixty-nine cases of placental abruption and placental hemorrhage detected with ultrasonography (US) were reviewed retrospectively to determine whether US findings correlate with fetal outcome. Four patients were lost to follow-up, and in the remaining 65 patients fetal outcome included demise in 12 cases (18%), termination of pregnancy in six (9%), premature delivery of a living infant in 15 (23%), term delivery of an infant who was small for gestational age in four (6%), and normal term delivery in 28 (43%). Fetal mortality correlated best with the estimated percentage of placental detachment, but was also significantly (P less than .01) associated with the location (retroplacental) and size (greater than 60 ml) of hemorrhage. Premature labor was associated (P less than .001) only with gestational age at the time of clinical presentation. No sonographic finding was identified as a risk factor for small-for-gestational-age infants. Sonographic findings of placental abruption correlate with fetal outcome, and this information may be useful for guiding obstetric management.     

MR imaging of non-CNS fetal abnormalities: a pictorial essay.

The recent popularity of prenatal magnetic resonance (MR) imaging has been associated with the development of ultrafast MR imaging techniques such as the single-shot fast spin-echo sequence. However, the majority of previous reports have concerned the fetal central nervous system (CNS) and chest disorders. MR imaging can demonstrate non-CNS fetal anatomy and pathologic conditions clearly. With its excellent tissue contrast, MR imaging provides information that supplements that provided by ultrasonography (US), especially in cases of neck, chest, and gastrointestinal lesions. Because of its large field of view, MR imaging allows evaluation of the relationship between a large lesion and adjacent structures. MR imaging should be considered if the diagnosis of a suspected non-CNS lesion is unclear at fetal US. MR imaging plays an important complementary role to US in cases of non-CNS fetal lesions and will be further accepted for fetal imaging in the future.     

Urethral abnormalities in male neonates with VATER association

In the past 3 years, eight of 20 male neonates with stigmata of the VATER association were found to have significant urethral abnormalities. Three had megalourethra, two had duplication of the urethra, and one each had an anterior urethral valve, congenital stricture, and hypospadias. In only five of eight was the extent of the abnormality clinically apparent. All three infants with megalourethra and imperforate anus died because of the coexistence of other severe congenital anomalies. Prior literature has described but not stressed the increased prevalence of urethral abnormalities in children with the VATER association. Because of the high prevalence (eight of 20) of significant urethral anomalies, we perform voiding cystourethrography on all males with the stigmata of the VATER association, even in the absence of clinical symptoms.     

Case report: lethal fetal head injury and placental abruption in a pregnant trauma patient

Fetal trauma in blunt abdominal trauma is uncommon, but traumatic fetal head injury is almost universally fatal to the fetus. Placental abruption is the most common injury to the gravid uterus in trauma, and when the mother survives, it is the most common cause of fetal death. The imaging diagnosis of these conditions may be difficult since there are only three cases reported in the literature of intrauterine skull fractures on plain films [3, 8, 10], ultrasound is in sensitive in the diagnosis of placental abruption [24], and the most sensitive test to diagnose placental abruption is external fetal monitoring with devices that measure uterine tone and contractility and fetal heart rate [23]. The diagnosis of fetal trauma and placental abruption may be made on contrast enhanced CT performed through the abdomen and pelvis of pregnant trauma patients. For these reasons, it is useful for the radiologist interpreting the CT scan to recognize fetal head injuries and placental abruption in pregnant trauma patients.Fig. 7 Axial scans through the bony pelvis demonstrate an unstable pelvic fracture with posterior pelvic ring disruption.There is a zone 2 fracture of the left sacrum and a fracture of the left obturator ring (arrowheads)     

Duplex ultrasonography of the fetal aorta, umbilical artery, and placental arcuate artery throughout normal human pregnancy

A cross-sectional duplex study of blood flow in the fetal aorta, umbilical artery, and arcuate arteries of 111 normal subjects was performed once at between 20 and 42 weeks gestation. Peak systolic velocity, end-diastolic velocity, mean velocity, and volume flow were measured in the fetal aorta, and systolic to diastolic (S/D) ratios were measured in all three vessels. Velocities show an inverse exponential (Y = Exp [1/X x B + C]) increase with gestational age, reaching a plateau just before term, while S/D ratios in the aorta and umbilical arteries show a linear decrease. Such findings are at variance with some published data. Our results suggest a reduction in fetal placental resistance at term and provide useful data concerning normal fetal and placental circulations.     

ECG and thallium imaging abnormalities with normal coronary angiogram in a male flight surgeon

Coronary artery disease and cardiac anomalies have the potential to cause sudden incapacitation in the flight environment with potentially disastrous consequences. Flight surgeons are responsible for screening for these potential diseases. We report a case of a healthy, active, asymptomatic U.S. flight surgeon returning for duty who demonstrated an abnormal ECG, graded exercise test, and thallium imaging. He was ultimately referred for cardiac catheterization that revealed normal coronary arteries. We discuss the sensitivity of non-invasive screening studies in healthy young individuals and potential causes of "false-positive" thallium imaging.     

Investigation of normal organ development with fetal MRI

The understanding of the presentation of normal organ development on fetal MRI forms the basis for recognition of pathological states. During the second and third trimesters, maturational processes include changes in size, shape and signal intensities of organs. Visualization of these developmental processes requires tailored MR protocols. Further prerequisites for recognition of normal maturational states are unequivocal intrauterine orientation with respect to left and right body halves, fetal proportions, and knowledge about the MR presentation of extrafetal/intrauterine organs. Emphasis is laid on the demonstration of normal MR appearance of organs that are frequently involved in malformation syndromes. In addition, examples of time-dependent contrast enhancement of intrauterine structures are given.     

Reversible MR imaging and MR spectroscopy abnormalities in association with metronidazole therapy

We present a report of MRI and proton MR spectroscopy (MRS) findings in an adolescent patient with Down syndrome and Crohn disease treated with metronidazole. MRI revealed signal abnormalities within the corpus callosum, basal ganglia, and brainstem. Proton MRS examination demonstrated a persistent lactate elevation during metronidazole treatment. Clinical, spectroscopic, and imaging abnormalities resolved with discontinuation of metronidazole.     

Fetal magnetic resonance imaging: indications,technique, anatomical considerations and a review of fetal abnormalities

Fetal MR imaging often poses a diagnostic challenge for the radiologist. Both fetal anatomy and pathology differ decidedly from pediatric and adult MR imaging. While ultrasound remains the method of choice for screening examinations of the fetus, MR imaging is playing an increasingly important role in the detection and classification of malformations not diagnosable by ultrasonography alone. Recently, advances in fast single-shot MR sequences have allowed high-resolution, high-quality imaging of the moving fetus. Preferable sequences to be applied are a true fast imaging steady precession (true-FISP) or a half-Fourier acquired single-shot turbo spin-echo (HASTE) sequence. Premedication is generally no longer required. In all fetal MR imaging, every aspect of fetal anatomy has to be scrutinized. Subsequently, any abnormalities need to be described and classified. A close collaboration with the referring obstetrician is of paramount importance.     

Complex genitourinary abnormalities on fetal MRI: imaging findings and approach to diagnosis

OBJECTIVE: The objective of this article is to present the fetal MRI patterns of complex genitourinary abnormalities including epispadias-exstrophy complex, cloacal malformation, urogenital sinus anomaly, posterior urethral valves, and other causes that result in lower urinary tract dilatation without oligohydramnios. Relevant embryology will be reviewed, and practical points will be provided that can aid in interpretation. CONCLUSION: Complex genitourinary abnormalities have recognizable imaging findings on fetal MRI. Imaging findings may be subtle; a high index of suspicion and a systematic checklist are useful for accurate diagnosis. Familiarity with fetal MRI patterns of complex genitourinary abnormalities is crucial for making more precise diagnoses that will likely impact pregnancy management, counseling, and postnatal treatment.