Fig. 1

Normal control (female mouse, 67 weeks old at the MRI, specimen Xray, and histology). A, B: Soft X-ray images of thoracic and lumbar spine and pelvis A and the thoracolumbar spine B. The cortical surface of the vertebrae is shown as high density on the side of the vertebrae, and the cancerous bone of the vertebrae is less dense than the cortical surface. The intervertebral disc space is shown as a darker line. The growth plate at the edge of the bony vertebrae appears as a higher density line because of calcareous deposition. C, D: Histology around the intervertebral space of thoracolumbar spine (C × 40, D × 100). The cartilaginous end plate (CEP) is stained in light red and contains some blue chondrocytes, and there is no bony end plate. Between the CEP and vertebral body (VB), the growth plate (GP) is stained blue. The GP is approximately 100 μm thick and is seen as a blue layer consisting of structural cell layers of proliferating, prehypertrophic, and hypertrophic chondrocytes with insular light blue zones. Between the two CEP layers the nucleus pulposus (NP) and the annulus fibrosus (AF) are observed in the thick lentoid light blue compartment, spreading nearly the full width of the vertebrae. E: T1-weighted MR image corresponding to histology. Osseous structures, especially cortical bone and trabecular bone, have very low intensity. GP is observed to have a linear low intensity. Among the GPs, NP and AF and CEP had slightly greater intensities. F: T2-weighted MR image. Thc contour of the structures are less clear. The combination of NP and AF has a very high intensity in the intervertebral space and is considered a water-rich structure. CEP, cartilaginous end plate; VB, Vertebral body, AF, annulus fibrosus; NP, nucleus pulposus; RH, rib head