3D/4D OB Ultrasound: Basics, Tips, and Possibilities

Diana M. Strickland, RDMS, RDCSEast Carolina University – Brody School of Medicine

Greenville, NC

Technical considerations

• Optimal– Body surfaces– Tissue/fluid interfaces

• Suboptimal– Oligohydramnios– Fetal part against uterine wall

• Strong Echoes– Bone/ Spine

Surface Rendering:

Measurements

• More accurate CRL• Weight volume• Quantify AFV

Artifacts

• Some will be unique to 3D– need to recognize

• Dropout– may simulate missing limbs

• Fetal small parts• Fetal motion

Gynecology• Coronal and transverse vaginal quality

images of entire uterus• Septums• Adnexal masses

– size, wall structure, internal characteristics, vascularity

• Follicles• Fibroids• Endometrial thickness, Sonohysterography

Comparison with 2D Imaging

• Multiple views, planes, and angles• Volumetric storage -Better appreciate size• Photographic quality image

– Improved patient understanding

ADVANTAGES

Comparison with 2D Imaging

• Slow learning curve

• Placental interference

• Obesity• Oligohydramnios

• Small parts interference

• Fetal motion (20%)• Expert sonographer• Expense

DISADVANTAGES

Clinical Applications• Still not a necessary component for

diagnosis (Adjunct)• May Improve Diagnosis

– Confirmation of a 2D diagnosis– Helps to re-evaluate after initial diagnosis

• Counseling– Help patient to conceptualize diagnosis

4D or STIC

• Dynamic view of beating heart• Fetal movement and behavior *• Placental blood Flow

Serial 3D

* http://www.ob-ultrasound.net/images/yawn.mov

Gated 3D

Transparency Mode

X-ray Mode