A method and system for guiding imaging reading for colon screening includes scrolling through a succession of two dimensional (2D) cross-sectional images of a colon in respective image planes. A point of intersection with a current image plane with the centerline of the colon is marked in a first color in the current cross-sectional image. As the scrolling proceeds and a new current cross-sectional image in a respective image plane is observed. a new point of intersection is marked in the current cross-sectional image in the first color and the prior point of intersection is projected onto the new current cross-sectional image and marked in a second color.