Late contrast enhancement in the CT diagnosis of herniated lumbar disk.

Twenty-five patients clinically suspected of herniated lumbar disk have undergone a CT examination before and 40 min after contrast enhancement. In every case, 13 of which were surgically verified, significant contrast enhancement of herniated disks was seen; there was only one false positive case. The authors conclude that late contrast enhancement really improves the CT diagnosis of herniated lumbar disk, particularly in cases with a doubtful or negative precontrast scan. The mechanism of the late contrast enhancement is discussed.