Diagnostic Imaging of Thoracic OPLL and OLF

Abstract

The most standard diagnostic imaging modality for ossification of the posterior longitudinal ligament of the spine (OPLL) and ossification of the ligamentum flavum (OLF) is a plain radiography; however, standard plain radiography is not an adequate for diagnosis of thoracic OPLL (T-OPLL) and thoracic OLF (T-OLF) because of the characteristic anatomy of thoracic region. Computed tomography (CT) is probably the most suitable modality to identify the ossified lesions. It is especially useful for the precise evaluation of T-OPLL and T-OLF. Magnetic resonance (MR) imaging cannot distinguish between ossifications of the spinal ligaments and hypertrophied spinal ligaments; however, it helps us to evaluate not only the extent of spinal cord compression, but also the intensity change of spinal cord due to compression by T-OPLL and T-OLF. It is important to make correct diagnosis of T-OPLL as well as T-OLF using multiple diagnostic imaging modalities.