In this ancient fable, the blind men (in the Chinese version since 202 BC) or the blind mice (in the English version by John G. Saxe since 19th century) try to identify an elephant. Each examines a small region and reaches a different conclusion, a pillar, a snake, a cliff, a spear, a fan, or a rope. One can summarize the tale with a mouse moral: “Knowing in part may make a fine tale, but wisdom comes from seeing the whole\". The fundamental issues in this ancient fable are actually common in scientific imaging, where one must compromise among a number of parameters such as resolution, field-of-view, signal-to-noise ratio, and time.
These issues in scientific imaging will be illustrated in the context of articular cartilage, which is the connective tissue coating the ends of bone in joints to provide a smooth surface for joint motion and to cushion the joint against shock impact. Although cartilage degradation is examined clinically on a morphological scale, the early events that weaken the load-bearing ability of cartilage occur at molecular and microscopic levels. Without intervention, these molecular and microscopic changes will lead to osteoarthritis, one of the most common diseases in human.
Over the last eighteen years at Oakland University, we study articular cartilage using multidisciplinary imaging techniques, including microscopic magnetic resonance imaging (µMRI), polarized light microscopy (PLM), Fourier-transform infrared imaging (FTIRI), microscopic computer tomography (µCT), and transmission electron microscopy (TEM). Together with biochemical assays and biomechanical testing, we correlate among different biological, chemical, physical properties of the tissue and discriminate among the various possible degradation states of the tissue. We examine the influence of the molecular and microscopic changes on tissue’s functional integrity, providing critical information towards the understanding, and ultimately, management of early arthritic diseases. Some latest results in cartilage studies (both articular cartilage and nasal cartilage) will be discussed.
- Y Xia, "Magic Angle Effect in MRI of Articular Cartilage - A Review", Investigative Radiology, 35(10), 602-621 (2000). [Review]
- Y Xia, "Relaxation Anisotropy in Cartilage by NMR Microscopy (µMRI) at 14 µm Resolution", Magnetic Resonance in Medicine, 39, 941-949 (1998).
- Y Xia, J Moody, N Burton-Wurster, and G Lust, "Quantitative In Situ Correlation Between Microscopic MRI and Polarized Light Microscopy Studies of Articular Cartilage", Osteoarthritis and Cartilage, 9 (5), 393-406 (2001).
- Y Xia and K Elder, \"Quantification of the Graphical Details of Collagen Fibrils in Transmission Electron Micrographs", Journal of Microscopy, 204 (Pt 1), 3-16 (2001).
- H Alhadlaq, Y Xia, J B Moody, J Matyas, "Detecting structural changes in early experimental osteoarthritis of tibial cartilage by microscopic magnetic resonance imaging and polarised light microscopy ", Annals of Rheumatic Diseases, 63 (6), 709-717 (2004).
- Y Xia, “Resolution 'scaling law' in MRI of articular cartilage”, Osteoarthritis and Cartilage, 15(4), 363-365 (2007). [Editorial]