Orientations and MetaImage Validation
The orientation code maps the pixel coordinate system I (column) J (row) K (slice) to right-handed coordinate system X Y Z. Characters R (right), L (left), A (anterior), P (posterior), I (inferior), S (superior) identify from direction.
RAI ¹, the default orientation ² ³, means
X: patient Right to left
Y: patient Anterior to posterior
Z: patient Inferior to superior