CT differentiation between recurrent disc herniation and postoperative scar formation: the value of contrast enhancement.

A study for the evaluation of the reliability of contrast enhanced CT in the differentiation between recurrent disc herniation and hypertrophic scar formation was undertaken. From the retrospective analysis of 36 surgically verified cases it became evident that hypertrophic scar tissue shows definite contrast enhancement, whereas recurrent disc herniation remains unenhanced. A possible explanation for this phenomenon is given. It is concluded that contrast enhancement should be performed in cases being studied by CT for recurrent symptoms after operation for disc herniation.