Objectives Define common terms related to 3D/4D ultrasound Chapter 32 3-D and 4-D imaging in Obstetrics and Gynecology Bridgette Lunsford Describe how 3D and 4D imaging differs from 2D ultrasound Identify the advantages and disadvantages of 3D/4D ultrasound List the benefits and drawbacks of the three acquisition techniques Recall 3D volume data set manipulation through use of the MPR format Objectives-continued List the advantages of using the MPR format Describe tomographic or multislice ultrasound imaging and list the benefits of this viewing format Explain common rendering modes and the clinical application of each Define VOCAL listing potential clinical applications in both OB and GYN imaging Describe common clinical applications for 3D ultrasound in obstetric and gynecological imaging Identify the concerns surrounding keepsake imaging and describe the current position of the ultrasound community What is Volume Ultrasound? Series of 2D images Includes 3D and 4D Image composition Pixel Voxel Limitations of 3D/4D Ultrasound What is Volume Ultrasound? 1
Benefits of 3D/4D Ultrasound Acquisition Techniques - Freehand Acquisition Techniques Sensor-based Acquisition Techniques - Mechanical Acquisition Techniques - Matrix Obtaining a 3D Volume Region of Interest (ROI) 2D - X and Y axis 3D Z axis 2
Obtaining a 3D Volume Obtaining a 3D Volume Acquisition speed Slow More slices Higher quality Larger volume size Fast Eliminates motion artifacts Obtaining a 3D Volume 3D Mulitplanar Reconstruction Most common display format Displays three orthogonal planes and the rendered volume. Orthogonal planes always 90 degrees to each other Planes A = acquisition plane B = orthogonal to A and C C = orthogonal to A and B 3D Mulitplanar Reconstruction 3D Mulitplanar Reconstruction 3
3D Mulitplanar Reconstruction Able to rotate data to create images on any plane Rotations X Y Z All plains remain orthogonal even during rotations Virtual re-scan 3D Mulitplanar Reconstruction C-plane Aka Z-plane Plane only acquired with a 3D data set Tomographic Ultrasound Imaging Tomographic Ultrasound Imaging Display of serial parallel images Similar to MRI or CT display Available with color Doppler modes Allows imaging for different anatomy Surface Threshold Eraser or scalpel Maximum, skeletal, or x-ray Inversion Glass body or transparency Virtual Organ Computer Aided Analysis (VOCAL) 4
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Virtual Organ Computer Aided Analysis or VOCAL Calculates the volume of an irregular object 3D model 3D versus 4D 3D Static image 4D Live or real-time image Mullerian duct anomailes Bicornuate vs. septate uterus Uterine contour Sonohystogram IUD location Essure coils tubal occlusion Tumor Doppler indices 6
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Artifacts Same as seen with 2D Display on three planes often confusing 8
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Spatio-temporal image correlation (STIC) Method to image the fetal heart 4D sequence of images obtaining both time and space Results in a real-time motion-gated image acquisition 10
Ethical Considerations/Parental Bonding The American Institute of Ultrasound in Medicine (AIUM) states, the AIUM advocates the responsible use of diagnostic ultrasound for all fetal imaging. The AIUM and the FDA both discourage the use of ultrasound for reasons not medically indicated Use of the Data set after Acquisition Data manipulation On machine Offline vendor specific software Currently no Digital Imaging and Communications in Medicine (DICOM) standard for 3D/4D data 11