Using a 3D Baby Ultrasound to Create Free 3D-Printed Models

As a field with ready access to three-dimensional data sets, radiology has been quick to embrace 3D printing technologies. By uploading DICOM files from CT scans, radiologists can easily convert scans into STL (a 3D printer-ready file format). One exciting area where 3D printing is being used is with expectant parents. By using the files from a 3D baby ultrasound, 3D-printed models of babies can be created — even while the child is still in the womb. But, the technology enabling these nifty keepsakes is also empowering pediatric physicians in some surprising ways. 

By evaluating the fetus through a 3D sonograph, OBGYNs can plan for maxillofacial, neurosurgical, or orthopedic surgeries prior to the birth of a child. This technology also allows many craniofacial abnormalities to be detected within the first trimester. This is important, medically speaking, as 

many facial deformities indicate a chromosomal issue that should be addressed prior to the birth of the child. Of course genetic testing is available, but as shown in a University of Washington Health Sciences/UW Medicine report, false positives can arise from the mother's extra DNA segments, so having an additional method to verify genetic issues is invaluable. 

You can also create 3D printed anatomical models by using conversion software such as democratiz3D® through the embodi3D® website. To get the most out of your time on the embodi3D® website and to put these tools to use, you first must register with embodi3D®. The process is simple, free, and you will only take a few minutes of your time.  

Sonography of the Normal Fetal Face
Sonographic evaluation of the fetal face is part of the routine anatomic survey in midpregnancy, but little is actually required. 
According to the American Institute of Ultrasound in Medicine 2013 practice guidelines, only visualization of the fetal upper lip is mandatory during an anatomic survey.1 Although not required, it is possible to obtain exquisite multiplanar two-dimensional (2-D), 3-D, and four-dimensional (4-D) vews of the fetal face with state-of-the-art equipment. Profile and 3-D views are helpful, especially when a true coronal view cannot be obtained because of fetal position. Sagittal 3-D volumes of the fetal face can often be obtained in these situations, and the image can then be rotated to show the upper lip and palate clearly.

Coronal and axial views of the fetal nose and lips are obligatory in screening for fetal cleft lip. 

The sagittal facial profile view is acquired whenever possible and should demonstrate the presence and normal configuration of the nasal bone, lips, chin, and forehead. Three-dimensional volumes can frequently be obtained and can be helpful for characterizing abnormalities. Axial views of the orbits can be obtained to verify that both globes are present, of normal size, and at a normal distance apart. Axial images of the maxilla and alveolar ridge can be obtained to determine if a cleft primary palate is present. The palate separates the nasal cavity from the oral cavity. The secondary palate is difficult to visualize on 2-D sonography but may be evaluated with special 3-D sonographic views and is often readily visible on midline sagittal and coronal fetal magnetic resonance imaging.

Congenital anomalies of the fetal airway represent a unique management challenge at birth and carry a significant risk of morbidity and mortality to the newborn. Congenital high airway obstruction syndrome (often referred to as CHAOS) may be identified on prenatal ultrasound by the presence of polyhydramnios, large echogenic lungs, and flattened diaphragms. These findings suggest complete obstruction of the fetal airway. However, in circumstances in which airway obstruction is not complete, such as with head and neck masses, predicting the severity of airway obstruction at birth is challenging. 

Facial Profile (Nasal Bone)
The appearance of the fetal nasal bone is an important sonographic marker utilized for identifying fetuses at increased risk for trisomy 21. The fetal nasal bone is evaluated on a midsagittal view of the fetal profile. The angle of insonation should be 90 degrees to the longitudinal axis of nasal bone although a slightly oblique angle (45 or 135 degrees) helps to define the edges of the nasal bone more sharply. If the nasal bone is viewed “on end” (0 or 180 degrees), it will appear erroneously as absent.In 239 fetuses referred for amniocentesis because of a risk of trisomy 21 of 1 in 270 or greater, Bromley et al. reported that 6 in 16 (37%) fetuses with trisomy 21 did not have a detectable nasal bone. Of the fetuses with a detectable nasal bone, the mean length was shorter in those with trisomy 21 than in euploid of trisomy 21 based on biparietal diameter (BPD)/nasal bone length (NBL) reveals that a cutoff of 11 or greater identifies 69% of trisomy 21 fetuses with a 5% FPR. Other authors recommend measurement of less than 5th percentile or an absolute measurement  of less than 2.5 mm as thresholds to predict aneuploidy.

There is variation in the prevalence of a hypoplastic or absent nasal bone depending on ethnicity. Cicero et al. reported that 8.8% of patients of African Caribbean ancestry had an absent or hypoplastic nasal bone, compared with 0.5% of Caucasian fetuses, thus limiting the utility of this marker in patients of African Caribbean heritage.

#1. A 3D Model of a Second Trimester Fetus in STL Format

Cristopher uploads a three-dimensional (3-D) sonogram of a normal 30 weeks fetus showing eyes, nose and lips. Prenatal sonographic evaluation of the fetal face and neck offers an opportunity to identify many abnormalities. These observations are often essential to prenatal counseling and prognosis because of the association of many of these abnormalities with syndromes and chromosomal anomalies. Appropriate diagnosis of abnormalities allows for planning of the appropriate mode of delivery and therapy when the fetal airway is potentially compromised.

#2. A 4D, Real-Time Ultrasound at Thirteen Weeks (Embryo Stage)

It shows head, superior and inferior limbs, chest and abdomen with exquisite detail.

#3. Fetal Face on a 4D Ultrasound

ducthangdr uploads this excellent file showing us the face of a second trimester fetus.

#4. A 4D Ultrasound of a Second Trimester Fetus

The face, nose and lips looks normal.

#5. Three-Dimensional (3-D) Sonogram of a Normal 30-Week Fetus

Pinates uploaded this excellent STL file showing a baby face.

#6. An Incredible 3D Model of a Baby Face!

A beautiful baby face.

#7. Three-Dimensional Sonogram Showing a Baby Face with Exquisite Detail

Different fetus at 30 weeks’ gestation coronal sonogram.

References

1. Jarvis, D., Griffiths, P. D., & Majewski, C. (2016). Demonstration of normal and abnormal fetal brains using 3D printing from in utero MR imaging data. American Journal of Neuroradiology, 37(9), 1757-1761.

2. VanKoevering, K. K., Morrison, R. J., Prabhu, S. P., Torres, M. F. L., Mychaliska, G. B., Treadwell, M. C., ... & Green, G. E. (2015). Antenatal three-dimensional printing of aberrant facial anatomy. Pediatrics, peds-2015.

3. Rumack, C. M., Wilson, S., Charboneau, J. W., & Levine, D. (2010). Diagnostic Ultrasound: 2-Volume Set. Missouri: Elsevier Mosby.