The imaging features of the meniscal roots on isotropic 3D MRI in young asymptomatic volunteers.

BACKGROUND: This study aimed to describe clearly the normal imaging features of the meniscal roots on the magnetic resonance imaging (MRI) with a 3-dimensional (3D) proton density-weighted (PDW) sequence at 3T.

METHODS: A total of 60 knees of 31 young asymptomatic volunteers were examined using a 3D MRI. The insertion patterns, constitution patterns, and MR signals of the meniscal roots were recorded.

RESULTS: The anterior root of the medial meniscus (ARMM), the anterior root of the lateral meniscus (ARLM), and the posterior root of the medial meniscus (PRMM) had 1 insertion site, whereas the posterior root of the lateral meniscus (PRLM) can be divided into major and minor insertion sites. The ARLM and the PRMM usually consisted of multiple fiber bundles (≥3), whereas the ARMM and the PRLM often consisted of a single fiber bundle. The ARMM and the PRLM usually appeared as hypointense, whereas the ARLM and the PRMM typically exhibited mixed signals.

CONCLUSIONS: The meniscal roots can be complex and diverse, and certain characteristics of them were observed on 3D MRI. Understanding the normal imaging features of the meniscal roots is extremely beneficial for further diagnosis of root tears.