MAGNETIC-RESONANCE SIGNALS IN HEALING MENISCI - AN EXPERIMENTAL-STUDYIN DOGS

This study examined the magnetic resonance imaging (MRI) signal from h ealing menisci in adult dogs. Complete, full-thickness radial tears we re created in the medial menisci of adult dogs and allowed to heal spo ntaneously. Menisci were harvested and examined at 8, 12, and 26 weeks after injury using a spin-echo imaging sequence. After imaging, the m enisci were processed for routine histologic examination. The results of the study demonstrated that the repair tissue consistently yielded an increased MRI signal as compared with the normal meniscal tissue. T his increased signal persisted at 26 weeks even though the repair tiss ue had modulated from fibrovascular scar tissue into fibrocartilage. T he results of this study confirm the clinical impression that normal f ibrovascular repair tissue in the healing meniscus can emit persistent ly increased signals on MRI examination. However, the long-term histor y of these signals remains unknown.