The Fetus with Ganglionic Eminence Abnormality: Head Size and Extracranial Sonographic Findings Predict Genetic Diagnoses and Postnatal Outcomes

BACKGROUND AND PURPOSE

Ganglionic eminence abnormalities on fetal MR imaging are associated with cerebral malformations. Their presumed genetic basis and associated postnatal outcomes remain largely unknown. We aimed to elucidate these through a multicenter study.

MATERIALS AND METHODS

Between January 2010 and June 2020, seven hospitals in 2 countries performing fetal MR imaging examinations identified fetal MR imaging studies demonstrating ganglionic eminence enlargement, cavitation, or both. Cases with no genetic diagnosis, no whole exome sequencing, or no outcome of a liveborn child were excluded. Head size was classified as large (fronto-occipital diameter > 95th centile), small (fronto-occipital diameter <5th centile), or normal.

RESULTS

Twenty-two fetuses with ganglionic eminence abnormalities were identified. Of 8 with large heads, 2 were diagnosed with MTOR mutations; 1 with PIK3CA mutation-producing megalencephaly, polymicrogyria, polydactyly, hydrocephalus (MPPH) syndrome; 3 with TSC mutations; 1 with megalencephaly capillary malformation syndrome; and 1 with hemimegalencephaly. Cardiac rhabdomyoma was present prenatally in all cases of TSC; mutation postaxial polydactyly accompanied megalencephaly capillary malformation and MPPH. Of 12 fetuses with small heads, 7 had TUBA1A mutations, 1 had a TUBB3 mutation, 2 had cobblestone lissencephaly postnatally with no genetic diagnosis, 1 had a PDHA1 mutation, and 1 had a fetal akinesia dyskinesia sequence with no pathogenic mutation on trio whole exome sequencing. One of the fetuses with a normal head size had an OPHN1 mutation with postnatal febrile seizures, and the other had peri-Sylvian polymicrogyria, seizures, and severe developmental delay but no explanatory mutation on whole exome sequencing.

CONCLUSIONS

Fetal head size and extracranial prenatal sonographic findings can refine the phenotype and facilitate genetic diagnosis when ganglionic eminence abnormality is diagnosed with MR imaging.

Clinical summary guide: reproduction in women with previous abdominopelvic radiotherapy or total body irradiation

STUDY QUESTION

What is the evidence to guide the management of women who wish to conceive following abdominopelvic radiotherapy (AP RT) or total body irradiation (TBI)?

SUMMARY ANSWER

Pregnancy is possible, even following higher doses of post-pubertal uterine radiation exposure; however, it is associated with adverse reproductive sequelae and pregnancies must be managed in a high-risk obstetric unit.

WHAT IS KNOWN ALREADY

In addition to primary ovarian insufficiency, female survivors who are treated with AP RT and TBI are at risk of damage to the uterus. This may impact on its function and manifest as adverse reproductive sequelae.

STUDY DESIGN SIZE DURATION

A review of the literature was carried out and a multidisciplinary working group provided expert opinion regarding assessment of the uterus and obstetric management.

PARTICIPANTS/MATERIALS SETTING METHODS

Reproductive outcomes for postpubertal women with uterine radiation exposure in the form of AP RT or TBI were reviewed. This included Pubmed listed peer-reviewed publications from 1990 to 2019, and limited to English language..

MAIN RESULTS AND THE ROLE OF CHANCE

The prepubertal uterus is much more vulnerable to the effects of radiation than after puberty. Almost all available information about the impact of radiation on the uterus comes from studies of radiation exposure during childhood or adolescence.An uncomplicated pregnancy is possible, even with doses as high as 54 Gy. Therefore, tumour treatment doses alone cannot at present be used to accurately predict uterine damage.

LIMITATIONS REASONS FOR CAUTION

Much of the data cannot be readily extrapolated to adult women who have had uterine radiation and the publications concerning adult women treated with AP RT are largely limited to case reports.

WIDER IMPLICATIONS OF THE FINDINGS

This analysis offers clinical guidance and assists with patient counselling. It is important to include patients who have undergone AP RT or TBI in prospective studies to provide further evidence regarding uterine function, pregnancy outcomes and correlation of imaging with clinical outcomes.

STUDY FUNDING/COMPETING INTERESTS

This study received no funding and there are no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Interobserver agreement and diagnostic performance of individual MRI criteria for diagnosis of placental adhesion disorders

AIM

To assess the diagnostic accuracy of several criteria for the diagnosis of placental adhesion disorder (PAD) on magnetic resonance imaging (MRI) and to assess interobserver agreement and reader accuracy based on years of interpretive experience.

MATERIALS AND METHODS

Blinded evaluation of the placental MRI studies of 28 randomly selected women, 18 with PADs and 10 without PADs, was undertaken by three radiologists with 10, 5, and 2 years' experience in placental MRI interpretation. The presence of placenta praevia, dark intraplacental bands, heterogeneity, uterine bulging, "shaggy dog" appearance of the uterine serosa, subjective impression of extraplacental invasion, and dark intraplacental bands on diffusion-weighted imaging were assessed. Placental histology was reviewed blinded to the original reports and to MRI interpretation and this, along with clinical information at the time of delivery, formed the reference standard.

RESULTS

Dark intraplacental bands on T2-weighted imaging were the most sensitive and specific as well as the most agreed upon (kappa=0.7) criterion for PAD for the three readers. Assessment of uterine bulging (kappa=0.42) and placental heterogeneity (kappa=0.48) did not improve diagnostic accuracy. DWI improved sensitivity but decreased specificity for the least experienced reader and did not change sensitivity or specificity for the more experienced readers.

CONCLUSION

Assessment of the placenta for dark bands is the most sensitive, specific, and reproducible criterion for diagnosis of PADs using MRI.