Tracing the planned probe trajectory on axial computed tomography slices: a computation-based support for...

Stereotactic frames are designed to hit point-like intracranial targets. Their routine performance does not include a display of the intended transcerebral probe path. Since the latter can render stereotactic procedures safer, more accurate and versatile, it has increasingly been implemented by potent computer systems. A low-cost alternative is presented in the form of a small extension of the computation program which is usually employed for the conversion of imaging coordinates to frame adjustments. It allows any desired point on the planned probe trajectory, in terms of its distance to the target, to be defined in Cartesian coordinates and thus to be traced on computed tomography. Thus, in biopsy procedures, for instance, instead of sampling tissue at the target only or in a 'blind' serial way, samples can be collected in a previewed and therefore safer and more purposeful way, thereby improving the yield of pathological tissue. The method seems particularly interesting for institutions that have a low to moderate number of stereotactic procedures and for which the investment of sophisticated computer systems for this purpose alone would not be economically feasible.