Superimposition reformatted CT for preoperative lesion localization and surgical planning.

With computer reformatting techniques, it is possible to project any lesion into its proper position with respect to the reformatted midsagittal computed tomography (CT) plane, the reformatted biparietal CT plane, or any other useful reference plane. The calvarial contour depicted on the reformatted midsagittal CT image is exactly comparable to the calvarial contour seen on a true lateral skull radiograph, and the calvarial contour depicted on the reformatted biparietal CT image is exactly comparable to the biparietal calvarial contour seen on the standard frontal skull radiograph. Using simple geometric proportions, therefore, it is easy to transfer the projection of a lesion from the reformatted images onto true lateral and frontal skull radiographs to provide neurosurgeons and radiotherapists with frontal and lateral pictures of the lesion and the skull suitable for planning surgical incisions and radiation portals.