If a CT image is labeled incorrectly and there is no anatomic finding or clear-cut symptom of laterality to raise suspicion of an error, the operation may be performed on the wrong side despite all preoperative preparation.

When the three dimensional "R" rod is imaged, a two dimensional "R" is scanned into the image next to the patient.

You can see this scan is clearly marked with the letter "R" on the "Correct Side".  Even if the scanner reverses the image, there will be no question of orientation.