[MRI in testicular diagnosis: differentiation of seminoma, teratoma and inflammation using a statistical score]

To differentiate scrotal pathology via MRI by means of a statistical score.

Between 1989 and 1995 MR images of 105 patients with scrotal pathology were rated retrospectively. In 69 cases linear discriminant analysis was used to differentiate seminoma, teratoma and inflammation. Six MRI attributes were found to be necessary and were weighted with a factor according to their importance. These factors were used to build a score.

Criteria found to be important contained the distribution of the variate extensions of elements inside the pathological area and their maximal and minimal signal intensities. Furthermore, the contrast pattern of the pathological area and the visibility of healthy tissue in the pathological testicle was of importance. Seminoma was found to be homogeneous and well demarcated against healthy tissue. Teratoma was also well defined but characterised by inhomogeneous distribution of signal intensities. Inflammation showed diffuse signal increase of the pathological testicle, especially in T1-sequences. Using the score differentiation between tumors and inflammation succeeded in 94.2% between seminoma and teratoma in 89.7%.

Compared to other studies using visual MR image analysis differentiation of scrotal diseases was improved by using a statistical score.