CT demonstration of the phrenic nerve.

Twenty-four consecutive patients examined with whole lung computed tomography (CT) using a high resolution scanner were evaluated for detection of the phrenic nerve. The phrenic nerve was considered to be demonstrable when a 1-3 mm rounded structure was identified adjacent to the pericardium on at least two contiguous sections. The phrenic nerve was thus indicated in 13 patients, eight children and five adults. The nerve was found on the left side in 11 patients, the right side in one patient, and bilaterally in one patient. It is important to recognize the normal course of the phrenic nerve on CT in patients being evaluated for pulmonary metastases.