Geometry Parameters for Copy Custom Function

FOV Read (Frequency Direction)

Defines the physical size of the image along the frequency-encoding axis.

• Effect: Smaller FOV increases resolution but may cause aliasing if anatomy exceeds coverage
• Tip: Balance coverage, resolution, and SNR—smaller voxels generally reduce SNR

FOV Phase

Defines coverage along the phase-encoding direction (shown as arrow lines).

• Effect: Reducing FOV Phase only shortens scan time if Matrix Phase is also reduced
• Tip: Reducing phase steps directly reduces scan time but increases foldover risk

Foldover Direction

Specifies the phase-encoding direction (RL, AP, or FH).

• Effect: Determines where aliasing appears
• Tip: Change foldover direction to shift aliasing away from anatomy of interest
• Note: When copied, this parameter is embedded in the Center Slice Position and may need manual adjustment

Matrix Read

Number of pixels in the frequency direction.

• Effect: Higher values increase in-plane resolution
• Tip: For 2D scans, does not directly increase scan time, but higher bandwidth may reduce SNR

Matrix Phase

Number of phase-encoding steps (k-space lines).

• Effect: Directly increases scan time and motion sensitivity
• Tip: Use practical values (e.g., 256–320) unless high detail is required

Slice Thickness

Physical thickness of each slice.

• Effect: Thicker slices improve SNR but reduce spatial detail
• Tip: Use thin slices for small anatomy or isotropic imaging

Slice Gap

Spacing between slices.

• Effect: Reduces crosstalk but leaves gaps in coverage
• Tip: Interleaved acquisition helps reduce crosstalk with minimal gap

Slice Number

Total number of slices acquired.

• Effect: More slices increase coverage and scan time (for 2D)
• Tip: Plan coverage based on anatomy size and protocol needs

In-Plane Orientation

Defines the acquisition plane (sagittal, coronal, transverse, or oblique).

• Effect: Determines anatomical view and partial-volume behavior
• Note: Copied via slice positioning—adjust using the yellow cutlines if needed

Center of the Slice (Center Position)

Defines the 3D location where the slice group is centered relative to the scanner isocenter.

• Effect: Ensures optimal field homogeneity and anatomical coverage
• Tip: Always center over the region of interest for consistent alignment across sequences
• Note: Copying this also propagates orientation and foldover direction

Slice Angulation

Rotation of the imaging plane relative to scanner axes.

• Effect: Aligns slices to anatomy and reduces partial-volume artifacts
• Tip: Use oblique angulation for curved or complex anatomy

Saturation Bands

Pre-saturation slabs used to suppress unwanted signal.

• Effect: Reduce motion and flow artifacts
• Tip: Place near vessels or anatomy prone to motion

Slice Groups (Multiple Stacks)

Multiple independently positioned slice groups.

• Effect: Enables imaging of non-contiguous or angled anatomy in one scan
• Tip: Ideal for knees, TMJ, spine regions, and bilateral structures

Conclusion

You've learned the key Geometry parameters that matter when using the Copy custom function, and how to ensure your copied setup matches your intended scan.