Unfortunately, these assessment methods cannot reliably diagnose early selleck chemicals cartilage injury and degeneration prior to loss of articular cartilage surface integrity, following which the pathological changes may be irreversible [4]. Experimental evidence shows that chondrocyte metabolic deficits occurring prior to breakdown of the articular surface may be reversible [5]. As such, clinically useful methods to detect subsurface cartilage injury and degeneration are important for development and testing of chondroprotective and chondrorestorative therapies. Optical Coherence Tomography (OCT) is a novel, nondestructive imaging technology capable of near-real-time cross-sectional imaging of articular cartilage at high resolutions comparable to low power histology [6�C11].
The following describes the advent of OCT for arthroscopic imaging of articular cartilage and the potential use of OCT as a new clinical tool for enhanced clinical diagnosis and staging of early cartilage injury and degeneration. 2. Current Clinical Imaging Modalities Minimally invasive arthroscopic imaging of the articular cartilage is considered the clinical standard for detection of early cartilage injury and degeneration. During arthroscopy, the cartilage is graded from 0 to 4 using the Outerbridge scoring system (0 = firm cartilage, 1 = softening, 2 = fissuring of <50% of cartilage thickness, 3 = fissuring >50% of cartilage thickness, and 4 = exposed bone) [12]. Arthroscopy is primarily a surface imaging technology combined with subjective tactile probing.
As such, arthroscopy falls short of the laboratory assessment standards of histopathology, metabolic study and biomechanical testing. Experimentally, biopsy and histology can detect matrix degradation and structural breakdown in cartilage that exhibits no gross surface abnormalities when observed by arthroscopy [7]. However, this is not a practical means for routine clinical detection of early arthritis since histology requires removal and destruction of the tissue being examined. Historically, radiographs were used to diagnose osteoarthritis. However only end-stage bone-related changes are reliably detectable by radiographic exam which does not adequately show soft tissues or directly image articular cartilage. MRI, while being a noninvasive cross-sectional imaging technology, suffers from low resolution and the inability of standard MRI to discern matrix changes leading to cartilage ��softening�� [13].
As such, arthroscopy remains the current clinical standard for diagnosis and staging of early articular cartilage injury and degeneration. 3. Optical Coherence Tomography Optical Coherence Tomography (OCT) is a novel imaging modality that allows for a nondestructive, Cilengitide cross-sectional ��optical biopsy�� of tissue [10, 14].