3D/4D basics Flashcards
What is 3D imaging?
3D or 3 dimensional is the acquisition and evaluation of static data created by stacking a series of 2 dimensional images into a volume data set.
Third dimension is the depth of the stacked 2D images
ex: acquisition of axial, sagittal, and coronal plane images combined to create 3D image
3D = length, width & depth
What is 4D imaging?
4D sonography aka real time 3D sonography
The live acquisition of the volume data sets. 4th dimension is time.
The advantage of 3D imaging versus 2D
ability to rotate the compiled volume dataset to achieve a visualization of optimal imaging planes. This goes beyond simply viewing a region through the orthogonal planes (axial/sagittal/coronal).
Being able to see the off-axis planes that we are unable to obtain using conventional sonographic technologies is invaluable in the assessment of normal/abnormal anatomy and pathology.
3D/4D acquisition tips:
- 2D optimization: 3D and 4D images start with the foundation of a 2D ultrasound image. avoid artifacts or poor resolution image
- ROI (region of interest) size: adjust the size of ROI to encompass the anatomy of interest. Best practice is to expand or reduce the size of the ROI box to encompass principally the anatomy of interest
- volume angle/scan angle: adjusted to increase or decrease the size of the volume acquisition in the out-of-axis planes
- quality setting adjustment: increase or decrease the actual quality, or resolution, of the volume dataset. *note: 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
Volume Imaging A, B, C Planes & the Orientation Dot
What is A plane?
- acquired plane prior to activating 3D or 4D
- A plane size is controlled by the size of the 3D/4D ROI box size
Volume Imaging A, B, C Planes & the Orientation Dot
What is B plane?
- orthogonal to A plane, rotated clockwise 90 degree = 90 degree clockwise rotation of the A plane
- B plane size is controlled by the volume angle setting *the larger the volume angle, the wider the B plane would be
Volume Imaging A, B, C Planes & the Orientation Dot
What is C plane?
- orthogonal to A plane, rotated forward 90 degree *90 degree forward rotation of A plane
- Note: forward rotation toward the person viewing the image
- C plane size is also controlled by volume angle *the larger the volume angle, the taller the C plane would be
Volume Imaging A, B, C Planes & the Orientation Dot
What is orientation Dot (Axis)?
- The position of the orientation dot or axis point
- the point which all 3 orthogonal planes intersects in the volume data set
- depicts the same anatomic point in all 3 dimensions
- The proper placement of the orientation dot (or axis-point, or pivot-point) is the first and most important step.
Volume Imaging A, B, C Planes & the Orientation Dot
Why so important?
aids in understanding the displayed anatomy
Tip: place the orientation dot in the anatomy of interest prior to performing any volume manipulations
Volume Dataset Manipulations: X-Y-Z Axis Rotations
3D/4D dataset can be manipulated along X, Y, or Z axis to display the desired anatomy. Axis manipulation pivot around the orientation dot.
X-Axis manipulation results in…
- active plane rotating horizontally
- A plane is active during this X-axis manipulation
Volume Dataset Manipulations: X-Y-Z Axis Rotations
3D/4D dataset can be manipulated along X, Y, or Z axis to display the desired anatomy. Axis manipulation pivot around the orientation dot.
Y-Axis manipulation results in…
- active plane rotating vertically
- A plane is active during this Y axis manipulation
- Y-axis manipulation will elongate or foreshorten the anatomy around the pivot point/orientation dot
Volume Dataset Manipulations: X-Y-Z Axis Rotations
3D/4D dataset can be manipulated along X, Y, or Z axis to display the desired anatomy. Axis manipulation pivot around the orientation dot.
Z-Axis manipulation results in…
- active plane rotating clockwise or counter clockwise
- A plane is active during this z axis manipulation
- B plane and C plane are also affected by the Z axis manipulation of the A plane
Volume Dataset Manipulations: X-Y-Z Axis Rotations
3D/4D dataset can be manipulated along X, Y, or Z axis to display the desired anatomy. Axis manipulation pivot around the orientation dot.
Translation/Reference Slice manipulation results in…
- slice depth adjustments within the active plane
- A plane is active as the translation is adjusted
- B or C plane are not affected by the translation/reference slice manipulation
- orientation dot moves as the slice depth changed
By using Translation (or Reference Slice Manipulation) to achieve the best slice plane depth in the Acquired/Active (A) plane, your x-, y-, or z-axis manipulations will display the most clinically definitive scans.
Understanding how to manipulate 3-D and 4-D volume datasets is crucial in order to produce ideal displays of desired anatomy in ultrasound scanning
- place the dot at the anatomy of interest
- use translation to achieve the best slice plane depth
- rotate along X, Y, or Z axis in the active plane to display the anatomy of the interest
In 3D, 4 quadrant view is known as…..
multiplanar
