Diffusion of Gd-DTPA2− into articular cartilage

Abstract

The results revealed that passive diffusion of Gd-DTPA²⁻ was significantly slower than previously assumed, leading to overestimation of the GAG content at equilibrating times of few hours. Moreover, Gd-DTPA²⁻ distribution was found to depend not only on GAG content, but also on collagen content and diffusion direction. Interestingly, the dGEMRIC technique was found to be most sensitive to cartilage degradation in the early stages of diffusion process, suggesting that full equilibrium between gadopentetate and cartilage may not be required in order to detect cartilage degeneration.

Is T1ρ Mapping an Alternative to Delayed Gadolinium-enhanced MR Imaging of Cartilage in the Assessment of Sulphated Glycosaminoglycan Content in Human Osteoarthritic Knees? An in Vivo Validation Study

“…Despite the weak correlation, this finding suggests that, in addition to sGAG content, the integrity of cartilage extracellular matrix also has an influence on contrast material influx into cartilage. Therefore, dGEMRIC outcomes appear not to be dependent on sGAG content alone, which was recently also suggested by others (34,35). The difference between the strength in correlation between the outcomes of dGEMRIC and cartilage sGAG and collagen content, however, suggests that sGAG is the composite that has the most influence on contrast material distribution throughout the articular cartilage.…”

An Innovative Agent-Based Cellular Automata Framework for Simulating Articular Cartilage Biomechanics

“…As with previous studies, which found that the diffusion coefficient that controls diffusion rate based on Fick's law [267], decreased with depth, and it correlated positively with the fluid content and negatively with solid content, in particular, proteoglycan content [14,15,[268][269][270][271].…”

“…It has been showed experimentally that the diffusion of solutes increased with articular degeneration [15,270,277]. The diffusive transport also became faster after enzymatically degraded articular cartilage, which only digests proteoglycan [270,278,279].…”

“…5 ;Exp8h =[10.09 10.09 10.32 10.09 9.95 9.81 9.77 9.82 9.73 9.9 10.05 9.9 9.82 10.18 10.62 10.41 10.37 10.46 10.45] ; Exp8h = Exp8h' ; Exp8h = Exp8h + 0.04 ; Exp8h = Exp8h ./ Exp24h ; %11. 5 ;ExpTimeLR = [1 ;2 ;3;4;5;6;7;8;9;10;11;12;13;14;15;16;17;18;19] ; ExpTimeD = [1 ; 2 ; 3;4;5;6;7;8;9;10;11;12;13;14;15] ; DeltaV = DeltaV + EXU * APopulation(i+1,j) * Alph ; APopulation(i+1,j) = APopulation(i+1,j) * (1 -EXU * Alph) ; E(i+1,j) = APopulation(i+1,j) . * Alpha(i+1,j) ; else Alph1 = Alpha(i+1,j) ; Alph2 = Alpha(i+1,j+1) ; DeltaV = DeltaV + EXU * APopulation(i+1,j) * Alph1 + EXU * APopulation(i+1,j+1) * Alph2 ; APopulation(i+1,j) = APopulation(i+1,j) * (1 -EXU * Alph1) ; E(i+1,j) = APopulation(i+1,j) .…”

“…Non-invasive experimental methods such as magnetic resonance imaging (MRI) and computed tomography (CT), can provide structural data from inside the articular cartilage such as spatial distribution of the proteoglycans and collagens, and orientation of the collagen fibres, without disturbing its structure [9][10][11][12]. However, as non-destructive methods indirectly collect internal information of the articular cartilage via a radioactive tracer [13][14][15], only limited functional data for articular cartilage can be obtained [16,17]. Experimental data may be used to develop mathematical methods which are usually based on differential equations, which describe characteristics of the system as a set of functions and parameters [18,19].…”