Fetal tumors: imaging features

Although fetal tumors are rare, the prognostic and decision-making implications are substantial. The purpose of this pictorial essay is to highlight the most common tumors encountered during fetal imaging and to discuss the respective typical imaging findings. When appropriate, limited additional information regarding further considerations for patient care will be included.     

Congenital dacryocystocele: prenatal MRI findings

Background

Congenital dacryocystocele can be diagnosed prenatally by imaging. Prenatal MRI is increasingly utilized for fetal diagnosis.

Objective

To present the radiological and clinical features of seven fetuses with congenital dacryocystocele diagnosed with prenatal MRI.

Materials and methods

The institutional database of 1,028 consecutive prenatal MR examinations performed during a period of 4 years was reviewed retrospectively. The cases of congenital dacryocystocele were identified by reading the report of each MRI study.

Results

The incidence of dacryocystocele diagnosed with prenatal MRI was 0.7% (n?=?7/1,028). The dacryocystocele was bilateral in three fetuses. Mean gestational age at the time of diagnosis was 31 weeks. The indication for prenatal MRI was the presence or the suspicion of central nervous system abnormality in six fetuses and diaphragmatic hernia in one. Dacryocystocele was associated with an intranasal cyst in six of ten eyes. Prenatal sonography revealed dacryocystocele in only two of seven fetuses. Of eight eyes with postnatal follow-up, four did not have any lacrimal symptoms.

Conclusion

Prenatal MRI can delineate congenital dacryocystocele more clearly and in a more detailed fashion than ultrasonography. Presence of dacryocystocele was symptomatic in only 50% of our patients, supporting that prenatal diagnosis of dacryocystocele might follow a benign course.     

Fetal genitourinary imaging

The fetal urinary tract is routinely evaluated sonographically beginning in the first trimester with documentation of fetal bladder visualization. Fetal MR might be indicated to further clarify abnormalities found sonographically. The primary imaging modality for evaluation of the fetal kidney is US, which plays an important role in the detection of collecting system dilatation and parenchymal diseases that influence counseling and postnatal care. A commonly seen birth defect affecting the fetal kidney is pyelectasis. The significance of this finding has been extensively evaluated by a number of fetal imaging centers and will be presented in this review. Further topics of interest within the fetal genitourinary system include fetal renal parenchymal disorders and fetal bladder abnormalities. Characteristic imaging features, as well as developmental pathology and differential considerations, are discussed here.     

Fetal development of the hand, digits and digit ratio (2D:4D)

OBJECTIVE: The purpose of this study was to investigate growth patterns in human hands, digits and digit ratio (2D:4D) during the fetal period. METHODS: The study is carried out on 161 human fetuses (83 males, 78 females) free from external pathology or malformation with ages ranging between 9 and 40 weeks of gestation. Following general external measurements, length and width of the hand, digit lengths separate for each hand was measured, hand index and the ratio of the lengths of the 2nd finger to the 4th finger (2D:4D index) was computed. RESULTS: Means and standard deviations of the parameters with respect to gestational weeks, months and trimesters were calculated. There was a significant correlation between all parameters and gestational age (p<0.001). No significant differences were observed between sexes or sides for any of the parameters (p>0.05). 2D:4D ratio was significantly higher in females compared to males (p<0.05) and mean 2D:4D did not change with gestational age. CONCLUSION: Detailed information of hand and digit parameters related to the fetal period will reveal the extent of biological variations of hand and digit parameters to be used in future studies. We hope that data acquired in this study will facilitate other studies on hand and digit anomalies, pathologies and variations as well as diagnoses and treatments of such conditions conducted in obstetrics, perinatology, forensic medicine and fetal pathology departments.     

Fetal imaging in the skeletal dysplasias: Overview and experience

The skeletal dysplasias (osteochondrodysplasias) comprise a heterogeneous group of disorders that are characterized by generalized abnormalities of skeletal growth and development. Of approximately 125 well-described skeletal dysplasias, about 50 are clinically apparent and identifiable at birth. The prevalence of these dysplasias in the newborn is quite frequent and has been estimated to be between 3–4.5 per 10,000, and the overall frequency of skeletal dysplasias among perinatal deaths to be about 9 per 1,000. Over the past 23 years we have acquired an enormous experience in the International Skeletal Dysplasia Registry with skeletal dysplasias diagnosable at birth or earlier. More and more cases referred to the registry over the past 2 years have been diagnosed as abnormal by ultrasound during the second trimester. The results of our evaluation of almost 400 fetuses and stillborn babies with reference to detailed prenatal history and postmortem evaluation including radiographs, chondro-osseous morphology and even some biochemical and molecular studies are presented. The most common disorders diagnosed were osteogenesis imperfecta (OI), thanatophoric dysplasia, campomelic dysplasia and achondrogenesis type II. Twenty-two types of neonatally diagnosable skeletal dysplasias are discussed together with potential fetal (second trimester) ultrasound findings, the number of fetal ultrasound cases referred to this registry, the number of total cases of that disorder sent to our registry, and the inheritance pattern of that skeletal dysplasia. This information should prove helpful in the evaluation of future cases ascertained by ultrasonography in the second trimester.     

Fetal magnetic resonance imaging: jumping from 1.5 to 3 tesla (preliminary experience)

Several attempts have been made at imaging the fetus at 3 T as part of the continuous search for increased image signal and better anatomical delineation of the developing fetus. Until very recently, imaging of the fetus at 3 T has been disappointing, with numerous artifacts impeding image analysis. Better magnets and coils and improved technology now allow imaging of the fetus at greater magnetic strength, some hurdles in the shape of imaging artifacts notwithstanding. In this paper we present the preliminary experience of evaluating the developing fetus at 3 T and discuss several artifacts encountered and techniques to decrease them, as well as safety concerns associated with scanning the fetus at higher magnetic strength.     

Fetal thoracic MR imaging]

Ultrasonography is the method of choice for prenatal malformation screening, but it does not always provide sufficient informations to allow a correct diagnosis or an adequate abnormality evaluation. Fetal MRImaging (MRI) indications are increasing in order to complete sonographic findings. It has been initially used for evaluation of cerebral abnormalities, but it is more and more applied to other fetal areas. An adequate analysis of fetal chest and abdomen can be obtained with fast T2 and T1 weighted sequences. This allows an easy diagnosis of congenital diaphragmatic hernia and an evaluation of the consequences on pulmonary growth. Other pulmonary malformations can be also easily identified (cystic adenoid malformation, sequestration, bronchogenic cyst, tracheal or bronchial atresia). Therefore, fetal thoracic MRI contributes to a better understanding and evaluation of fetal thoracic malformations, which is particularly useful for their postnatal management.     

Fetal MR imaging of Kniest dysplasia

We present a case of Kniest dysplasia, a rare form of the type II collagenopathies, with prenatal MRI. Sonography revealed only short limbs in the fetus. Fetal MRI findings included enlarged hyaline cartilaginous structures with abnormally high T2 signal intensity, delayed ossification of the pubic and ischial bones, and platyspondyly. By delineating the cartilaginous abnormalities, fetal MRI can contribute to the prenatal diagnosis of chondrodysplasias.     

Real-time 3D ultrasound imaging of infant tongue movements during breast-feeding

Background

Whether infants use suction or peristaltic tongue movements or a combination to extract milk during breast-feeding is controversial. The aims of this pilot study were 1] to evaluate the feasibility of using 3D ultrasound scanning to visualise infant tongue movements; and 2] to ascertain whether peristaltic tongue movements could be demonstrated during breast-feeding.

Methods

15 healthy term infants, aged 2 weeks to 4 months were scanned during breast-feeding, using a real-time 3D ultrasound system, with a 7 MHz transducer placed sub-mentally.

Results

1] The method proved feasible, with 72% of bi-plane datasets and 56% of real-time 3D datasets providing adequate coverage [> 75%] of the infant tongue. 2] Peristaltic tongue movement was observed in 13 of 15 infants [83%] from real-time or reformatted truly mid-sagittal views under 3D guidance.

Conclusions

This is the first study to demonstrate the feasibility of using 3D ultrasound to visualise infant tongue movements during breast-feeding. Peristaltic infant tongue movement was present in the majority of infants when the image plane was truly mid-sagittal but was not apparent if the image was slightly off the mid-sagittal plane. This should be considered in studies investigating the relative importance of vacuum and peristalsis for milk transfer.     

Electroencephalography and brain magnetic resonance imaging in asphyxia comparing cooled and non-cooled infants

Objective

The aim was to establish any differences in the predictive value of EEG and MRI for outcome in infants treated and not-treated with therapeutic hypothermia (HT) for perinatal asphyxia. We hypothesize that they are equally predictive and that combining both has the highest predictive value.

Fetal MR imaging of atelosteogenesis type II (AO-II)

The diastrophic dysplasia family of osteochondrodysplasias comprises a spectrum of skeletal diseases characterized by abnormal growth and remodelling of cartilage and bone. They are caused by mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene. Different defects in this gene product give rise to the variety of phenotypes based on the level of residual transport capacity. We reported a case of a fetus with this spectrum, evaluated and diagnosed with fetal MRI.