Flip

The Flip tool mirrors volume and mask data along a specified axis. Flipping is useful for correcting orientation issues or creating mirrored versions of datasets.

Flip vs Swap Axes

Flip and Swap Axes are related, but they do different things:

• Flip mirrors the data along X, Y, or Z.
• Swap Axes changes which physical direction is treated as X, Y, or Z.
• Use Flip when the axis direction is inverted.
• Use Swap Axes when two axes are in the wrong order.

In short: Flip creates a mirrored result while keeping the same axis order, whereas Swap Axes reorders the axes themselves.

Accessing the Tool

1. Navigate to the Image tab in the ribbon.
2. Click Flip in the Transform section.

Parameters

Flip Axis

Select the axis along which to flip the data:

Axis	Effect
X	Mirrors left-to-right (sagittal flip)
Y	Mirrors front-to-back (coronal flip)
Z	Mirrors top-to-bottom (axial flip)

Flip Reference

Choose the reference point for the flip operation:

Option	Description
About origin	Flip using the coordinate system origin (0, 0, 0) as the mirror plane
About center	Flip using the object's geometric center as the mirror plane

Visual Effect

Flipping creates a mirror image:

• X-axis flip: Left becomes right, right becomes left
• Y-axis flip: Anterior becomes posterior, posterior becomes anterior
• Z-axis flip: Superior becomes inferior, inferior becomes superior

Workflow

1. Open the Flip tool from the Image tab.
2. Select the axis to flip along (X, Y, or Z).
3. Choose the flip reference (About origin or About center).
4. Click Apply to flip the data.

Use Cases

Correcting Import Orientation

Some data sources may have inverted axes:

1. Identify which axis is inverted by comparing to known anatomy.
2. Apply the appropriate flip to correct orientation.
3. Verify the result in orthogonal slice views.

Creating Mirrored Datasets

For bilateral symmetry analysis:

1. Flip a left-side dataset to create a right-side version.
2. Compare or overlay with actual right-side data.
3. Useful for symmetry studies and contralateral comparison.

Matching Coordinate Conventions

Different software may use different coordinate conventions:

• Right-handed vs. left-handed coordinate systems
• Different axis definitions (RAS, LPS, etc.)
• Flip as needed to match target conventions

If the issue is an exchanged axis order rather than an inverted direction, use Swap Axes instead.

Affected Objects

Flipping affects:

• All volume objects
• All mask objects

Both are flipped together to maintain spatial correspondence.

warning

Flipping may cause DICOM orientation metadata to become incorrect. Verify patient orientation labels after flipping medical datasets.

Medical Imaging Considerations

danger

In medical imaging, incorrect left-right orientation can have serious consequences. Always verify anatomical landmarks after flipping to ensure correct patient orientation.

Standard medical imaging conventions:

• R = Patient's Right
• L = Patient's Left
• A = Anterior (front)
• P = Posterior (back)
• S = Superior (head)
• I = Inferior (feet)

Scripting

This operation is available via the Python scripting API using flip().

import ScriptingApi as api

app = api.Application()
volume_operations = app.get_volume_operations()

# Flip along X axis about the origin
volume_operations.flip(
    ["Volume1"],
    api.FlipAxis.X,  # axis: api.FlipAxis.X, api.FlipAxis.Y, or api.FlipAxis.Z
    True             # about_origin: True=origin, False=center
)

# Flip along Z axis about the center
volume_operations.flip(["Volume1"], api.FlipAxis.Z, False)

See the VolumeOperations API Reference for details.

See also: Swap Axes