The need for skull radiography in patients presenting for CT.

One thousand patients had both CT of the head and a conventional skull series of radiographs. Radiographic findings were abnormal in 250 patients (25%), but only 64 patients (6.4%) had diagnostically significant abnormalities at radiography that were not detected by CT. If the 163 patients who presented after acute trauma were excluded from the series, only 39 (4.7%) of the remaining patients had radiographically significant abnormal findings that were not seen at CT, and only two (0.2%) of these abnormalities could not be diagnosed by a lateral skull radiograph alone. In only five patients (0.5%) was the management actively changed because an abnormality that was detected at skull radiography was not detected at CT. Thus, in nontrauma patients who have stroke, epilepsy, dementia, or nonspecific symptoms without focal signs, or have recently undergone craniotomy, and who have been referred for CT, skull radiographs are not justified. In the patient with a history and findings that are strongly suggestive of a pathological disorder anywhere other than in the sella turcica, cerebello-pontine angle, and paranasal sinuses, only the lateral skull radiograph should be obtained after CT, and only if CT is equivocal.