D. Pugash

Prenatal ultrasound and fetal MRI: the comparative value of each modality in prenatal diagnosis.

Fetal MRI is used with increasing frequency as an adjunct to ultrasound (US) in prenatal diagnosis. In this review, we discuss the relative value of both prenatal US and MRI in evaluating fetal and extra-fetal structures for a variety of clinical indications. Advantages and disadvantages of each imaging modality are addressed. In summary, MRI has advantages in demonstrating pathology of the brain, lungs, complex syndromes, and conditions associated with reduction of amniotic fluid. At present, US is the imaging method of choice during the first trimester, and in the diagnosis of cardiovascular abnormalities, as well as for screening. In some conditions, such as late gestational age, increased maternal body mass index, skeletal dysplasia, and metabolic disease, neither imaging method may provide sufficient diagnostic information.

The Use of Magnetic Resonance Imaging in the Obstetric Patient

OBJECTIVE To review the biological effects and safety of magnetic resonance imaging (MRI) in the obstetric patient and to review procedural issues, indications, and contraindications for obstetrical MRI. OUTCOMES This guideline is intended to reassure patients and clinicians of the safety of MRI in pregnancy and to provide a framework for its use. EVIDENCE Published literature was retrieved through searches of PubMed or Medline in 2013 using controlled vocabulary and key words (e.g., MRI, safety, pregnancy). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English and in French. There were no date restrictions. Searches were updated on a regular basis and incorporated in the guideline to July 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALUES The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table). BENEFITS, HARMS, AND COSTS This article is intended to reassure obstetric care providers that if used in an appropriate manner without the use of contrast agents, MRI in the obstetrical patient is safe for mother and fetus in the second and third trimesters. Because obstetrical MRI is expensive and has limited availability in Canada, this clinical guideline is intended to encourage the judicious use of this resource. SUMMARY STATEMENTS: 1. Fetal magnetic resonance imaging is safe at 3.0 tesla or less during the second and third trimesters. (II-2) 2. It is safe to continue breastfeeding after receiving a gadolinium contrast agent. (III) RECOMMENDATIONS: 1. Use of magnetic resonance imaging during the first trimester of pregnancy should be restricted to maternal indications for which the information is considered clinically imperative. Inadvertent exposure to magnetic resonance imaging during the first trimester has not been associated with any long-term sequelae and should not raise clinical concern. (III-C) 2. Gadolinium contrast may be used in pregnant women when the benefits outweigh the potential risks. (III-C).

Magnetic resonance spectroscopy of the fetal brain

Fetal magnetic resonance spectroscopy (MRS) is technically feasible in utero and demonstrates similar findings to those observed in neonatal populations. MRS can provide additional information to conventional T1‐ and T2‐weighted imaging of the fetal brain. It is of particular use when subtle changes are present on conventional fetal MRI sequences, and when imaging fetuses at risk of brain injury and metabolic abnormalities. Copyright

Schinzel-Giedion Syndrome : Report of Splenopancreatic Fusion and Proposed Diagnostic Criteria

We report on the 46th patient with Schinzel–Giedion syndrome (SGS) and the first observation of splenopancreatic fusion in this syndrome. In the antenatal period, a male fetus was found to have bilateral hydronephrosis. Postnatally, in keeping with a diagnosis of SGS, there were large fontanelles, ocular hypertelorism, a wide, broad forehead, midface retraction, a short, upturned nose, macroglossia, and a short neck. Other anomalies included cardiac defects, widened and dense long bone cortices, cerebral ventriculomegaly, and abnormal fundi. Splenopancreatic fusion, usually encountered in trisomy 13, was found on autopsy. Schinzel–Giedion syndrome is likely a monogenic condition for which neither the heritability pattern nor pathogenesis has yet been determined. A clinical diagnosis may be made by identifying the facial phenotype, including prominent forehead, midface retraction, and short, upturned nose, plus one of either of the two other major distinguishing features: typical skeletal abnormalities or hydronephrosis. Typical skeletal anomalies include a sclerotic skull base, wide supraoccipital‐exoccipital synchondrosis, increased cortical density or thickness, and broad ribs. Other highly supportive features include neuroepithelial tumors (found in 17%), hypertrichosis, and brain abnormalities. Severe developmental delay and poor survival are constant features in reported patients.

Sonographic ‘molar tooth’ sign in the diagnosis of Joubert syndrome

The characteristic imaging finding common to Joubert syndrome and related disorders is the ‘molar tooth’ sign. The prenatal diagnosis of Joubert syndrome using both ultrasound and fetal magnetic resonance imaging (MRI) in families with an affected child has been reported previously. We report two cases in which the molar tooth sign was identified by sonography at 26 + 4 weeks and at 20 + 6 weeks, respectively, prior to fetal MRI or genetic testing. In both cases the finding was subsequently confirmed on fetal MRI. As definitive prenatal genetic testing may not be conclusive in Joubert syndrome, the ability to identify the molar tooth sign sonographically before 24 weeks provides a valuable adjunct to prenatal diagnosis. Copyright

MR Spectroscopy of the Fetal Brain: Is It Possible without Sedation?

BACKGROUND AND PURPOSE: The quality of spectroscopic studies may be limited because of unrestricted fetal movement. Sedation is recommended to avoid motion artefacts. However, sedation involves side effects. The aim of this study was to assess the feasibility and quality of brain 1H-MR spectroscopy in unsedated fetuses and to evaluate whether quality is dependent on the type of spectra, fetal presentation, GA, and/or fetal pathology. MATERIALS AND METHODS: Seventy-five single-voxel spectroscopic studies of the fetal brain, performed at gestational weeks 19–38 at 1.5T, were evaluated retrospectively. A PRESS (TE = 144 or 35 ms) was used. Fetal presentation, GA, and kind of pathology were recorded. The quality of the spectra was assessed by reviewing the spectral appearance (line width, signal-to-noise) of the creatine resonance obtained relative to concentrations (ratios-to-creatine) of choline, myo-inositol, and NAA. RESULTS: Of 75 studies, 50 (66.6%) were rated as readable: short TE = 17/50 (34%), long TE = 33/50 (66%), cephalic presentation in 36/50 (72%) studies, breech in 10/50 (20%) studies, and “other” presentation in 4/50 (8%) studies (mean GA, 31.0 weeks). Twenty-eight of 50 fetuses (56%) showed normal development (short TE = 12/28, long TE = 16/28), and 22/50 (44%) showed pathology. Of the 75 studies, 25 (33.3%) were not readable: short TE = 14/25 (56%), long TE = 11/25 (44%), cephalic presentation in 20/25 (80%) studies, breech in 4/25 (16%) studies, and other presentation in 1 study (4%) (mean GA, 30.1 week). Thirteen of 25 fetuses (52%) showed normal development; 12/25 (48%) showed pathology. Statistical analysis revealed no impact of the different parameters on the quality of spectra. CONCLUSIONS: Single-voxel spectroscopy can be performed in approximately two-thirds of unsedated fetuses, regardless of the type of spectra, fetal presentation, GA, and pathology.

Monoamniotic twins discordant for anencephaly managed conservatively with good outcomes: two case reports and a review of the literature

Monoamniotic twin pregnancy discordant for anencephaly (MATDA) is a rare occurrence with only seven prior reported cases. Selective termination has been advocated in managing discordant monoamniotic twins. We report two cases managed expectantly with good outcomes and review other previously reported cases. The first case was a primigravid woman diagnosed with MATDA at 18 weeks. She was managed expectantly until 32 + 5 weeks when a Cesarean section was performed for preterm labor. The surviving female infant weighed 1610 g. The second case was a multigravid woman who was diagnosed with MATDA at 17 + 5 weeks and was managed as an outpatient. An emergency Cesarean section was performed at 31 weeks for non‐reassuring monitoring and the surviving male infant weighed 1790 g. In both cases, the survivors were discharged home in good condition. A review of these two cases and those in the literature suggests that expectant management should be considered among management options for this rare condition. Copyright

Steroid sulfatase deficiency and contiguous gene deletion syndrome amongst pregnant patients with low serum unconjugated estriols

To ascertain all prenatally diagnosed cases of Steroid Sulfatase (STS) deficiency in British Columbia between August 2002 and July 2007 to determine the incidence of this condition, the clinical and laboratory findings, and the risk of a contiguous gene deletion syndrome.

Beckwith–Wiedemann syndrome in sibs discordant for IC2 methylation†‡

Genetically heterogeneous imprinting disorders include Beckwith–Wiedemann syndrome (BWS) and multiple maternal hypomethylation syndrome (MMHS). Using DNA sequencing, quantitative PCR, SNuPE, pyrosequencing, and hybridization to the Illumina GoldenGate Methylation Cancer Panel 1 array, we characterized the genomic DNA of two brothers with BWS who were discordant for loss of methylation at several differentially methylated regions (DMR), including imprinting center 2 (IC2) on chromosome band 11p15.5, which is often hypomethylated in BWS. In keeping with MMHS, the elder child had hypomethylation of SGCE and PLAGL1 as well as of IC2, whereas the younger brother demonstrated no loss of methylation at these DMRs. Although this discordance is consistent with the observation that 15–20% of individuals with BWS do not have detectable genetic or epigenetic alterations of 11p15.5, this is the first report of familial recurrence of BWS with discordance for chromosomal 11p15.5 alterations. We hypothesize that this apparent discordance arises either from mosaicism precluding identification of IC2 hypomethylation in blood or buccal mucosa DNA of the younger child, or from hypomethylation at a site not interrogated by our molecular studies.

First-Trimester Imaging of Combined Esophageal and Duodenal Atresia Without a Tracheoesophageal Fistula

To the Editor: A 39-year-old healthy primigravida was referred to our Fetal Diagnostic Service at 12 weeks’ gestation because of a recent sonographic finding of a fetal intra-abdominal malformation. At 12 weeks’ gestation, our images revealed that the biometric measurements were appropriate; the nuchal translucency was normal; and there was a single large cystic structure in the anterior upper abdomen. In Figure 1, the left image shows the large single cyst. The right image, lower in the abdomen, could be misinterpreted as a “double-bubble” sign. No other abnormality was seen. It was thought that these findings were more consistent with a dual obstruction of both the esophagus and the duodenum. After the diagnosis of trisomy 21 on chorionic villous sampling and pregnancy termination, fetal autopsy revealed atresia of both the duodenum and esophagus without a tracheoesophageal fistula. Tsukerman et al1 reported a case of duodenal stenosis and esophageal atresia in the first trimester in a fetus with a normal karyotype. The lesion they described was similar to a doublebubble sign consistent with isolated duodenal atresia during the first trimester.2 With a closed loop, we could postulate that the degree of duodenal and gastric distention is much greater than with isolated duodenal atresia. In our case, we observed a single large cystic lesion in the upper abdomen in the first trimester, in accordance with the observations of Estroff et al3 in the second trimester. It is possible that this arose because this closed loop of bowel had no possibility of drainage from a tracheoesophageal fistula. To our knowledge, this was the first time that this observation was made during the first trimester. In the near future, we will likely rely more on prenatal screening with nuchal translucency late in the first trimester. Sonographic findings similar to ours would be useful for adjusting the risk of aneuploidy. This would allow earlier prenatal diagnosis and possibly pregnancy termination at a gestational age that would be suitable for dilation and evacuation with a lesser degree of maternal morbidity.