Continuing our discussion on 3D/4D Ultrasound Imaging, today we will touch on the four primary factors to evaluate and refine to be successful in 3D/4D image acquisition.
3D dataset of uterus with IUD causing shadowing artifact
2D Optimization
3D and 4D images start with the foundation of a 2D ultrasound image. It is therefore critical to improve the overall quality of this “base” image. The presence of artifacts, or poor resolution in the underlying 2D image, will be replicated and possibly exacerbated in the byproduct 3D/4D image.
ROI* sizing
Once you have optimized the 2D image, and then activate 3D or 4D on the ultrasound system, a “Region-of-Interest”, or ROI box will appear. Best practice is to expand or reduce the size of the ROI box to encompass principally the anatomy of interest. Over time, experience will help you to balance the objective to isolate a particular region with an accompanying goal to maintain some perspective relative to proximate organs, tissue, or other anatomic structures.
ROI box (yellow-line) encompasses tissues posterior to the fetus on left image. Right image captures fetal anatomy inside gestational sac
Volume Angle* adjustment
Volume Angle, sometimes called the Scan Angle, is a button on the system console that is adjusted to increase or decrease the size of the volume acquisition in the out-of-axis planes. As with ROI sizing, the ideal is to gather imaging data that is relevant to the diagnostic requirements, without expanding the scanning planes beyond what is necessary.
3D volume datasets scanned with narrower (left) versus wider (right) Volume Angle settings
Quality* setting adjustment
Quality is a control on the system console that is adjusted to increase or decrease the actual quality, or resolution, of the volume dataset. Increasing the Quality setting results in an increase in the image acquisition time so as to improve the image resolution, but of course, decreasing the temporal resolution. This essentially means that you have to evaluate an ultrasound study’s specific requirements to assess whether spatial or temporal resolution is of greater importance.
Higher Quality setting (Right) will increase image acquisition time
* It is important to note that the system controls mentioned above have different names depending on the ultrasound system manufacturer.
Understanding the basics of how to acquire 3D/4D volume datasets gives you a framework to develop proficiency and to make adjustments to the datasets as necessary to achieve quality images for diagnosis. As with any new or developing skill, practice makes perfect.
Tip: Practice acquiring volume datasets on normal anatomy so that you are prepared to use your skills and experience while conducting more critical assessments of pathology in the future.
Click below to watch Quick Concept: 3D/4D Acquisition
