Computerized tomographic scan and gunshot wounds of the head: indications and radiographic findings.

The authors document their experience with the computerized tomographic (CT) scanner for evaluating gunshot wounds of the head. Only those patients who were considered to be operative candidates and who were neurologically stable were scanned. In the postoperative period, patients who were not scanned preoperatively and those whose condition did not improve were also scanned. In the preoperative period the CT scanner is useful for identifying and localizing missile tracks, bony and metallic fragments, intra- and extraparenchymal hematomas, intracranial air, and brain swelling. In the postoperative period the CT scanner may demonstrate retained bone fragments, edema, brain abscess, and intracranial air. The limitations of the CT scan in evaluating gunshot wounds include an inability to define vascular lesions suchas traumatic aneurysms and post-traumatic spasm. Metallic scatter from missile fragments may render certain CT cuts uninterpretable. In addition, the CT scan may appear minimally abnormal in spite of immediate and irreversible injury caused by a shock wave transmitted to brain stem structures. The CT scanner has superceded angiography as a diagnostic tool for evaluating gunshot wounds of the head because it is noninvasive and rapid, allows visualization of the entire head, can resolve very small lesions that produce little or no mass effect, can help to determine the nature of intracranial lesions and may quantitate the amount of hemorrhage and edema. Because it enables physicians to visualize intracranial structures in three dimensions, the CT scan may precisely define missile tracks and contiguous lesions in a manner not heretofore possible with other diagnostic modalities. Thus, it is invaluable for the rational planning of surgical therapy.