Revision 10 for 'Anterior commissure - posterior commissure line'All Revisions
The anterior commissure (AC) - posterior commissure (PC) line, also referred as the bicommissural line, has been adopted as a convenient standard by the neuroimaging community, and in most instances is the reference plane for axial imaging in everyday scanning. The creation of a standard image plane makes easier the comparison among exams.
It is prescribed on midline sagittal images and is similar to the orbitomeatal line traditionally used on CT, although the AC-PC line is typically ~9 degrees steeper than the orbitomeatal line 2.
An alternative and less commonly used description of thine proposed by Schaltenbrand draws the line trough the midpoint of both the anterior and posterior commissure, resulting in a slightly shallower angle 1,3.
Use for CT of the brain
Prior to widespread volumetric CT brain acquisition which has allowed axial images to be reformatted along the AC-PC line, a number of techniques were developed to approximate the CT gantry tilt such that axial images generated were similar to the AC-PC line. Such methods incldue:
- tuberculum sellae and the external occipital protuberance line 4
- hard palate line + 12 degrees 5