Verification of Extensive Bone Marrow Hyperplasia Using Magnetic Resonance Imaging

Abstract

Bone marrow hyperplasia of the rib, lumbar spine, knee, and iliac crest is frequently encountered in patients undergoing magnetic resonance imaging (MRI) examination. In this study, we investigated extensive areas of bone marrow hyperplasia of the ascending mandibular ramus, posterior to the inferior alveolar nerve, the size of the lesions ranging from 5 to 7 cm. In a prospective study, an orthopantomography (OPT) was performed in 15,412 patients. Seven patients in the study group (0.05%) showed extensive bone marrow hyperplasia in the ascending mandibular ramus. The diagnosis derived by means of the OPT was confirmed by T1-weighted MRI with and without fat signal suppression and was finally proved by means of the histological findings from a bone biopsy. This investigation shows that a T1-weighted MR image with and without fat signal suppression shows a typical heterogeneous distribution of signal intensity with a unique pattern not found in other lesions. The MRI-based diagnosis in our study group was always confirmed by means of a bone biopsy performed via a transbuccal approach. We conclude that properly selected MRI studies are by themselves adequate to diagnose these lesions and that these imaging studies supplant the need for a bone biopsy.