Synchrotron MicroCT Reveals the Potential of the Dual Contrast Technique for Quantitative Assessment of Human Articular Cartilage Composition

Abstract

Dual contrast micro computed tomography (CT) shows potential for detecting articular cartilage degeneration. However, the performance of conventional CT systems is limited by beam hardening, low image resolution (full‐body CT), and long acquisition times (conventional microCT). Therefore, to reveal the full potential of the dual contrast technique for imaging cartilage composition we employ the technique using synchrotron microCT. We hypothesize that the above‐mentioned limitations are overcome with synchrotron microCT utilizing monochromatic X‐ray beam and fast image acquisition. Human osteochondral samples (n = 41, four cadavers) were immersed in a contrast agent solution containing two agents (cationic CA4+ and non‐ionic gadoteridol) and imaged with synchrotron microCT at an early diffusion time point (2 h) and at diffusion equilibrium (72 h) using two monochromatic X‐ray energies (32 and 34 keV). The dual contrast technique enabled simultaneous determination of CA4+ (i.e., proteoglycan content) and gadoteridol (i.e., water content) partitions within cartilage. Cartilage proteoglycan content and biomechanical properties correlated significantly (0.327 < r < 0.736, p < 0.05) with CA4+ partition in superficial and middle zones at both diffusion time points. Normalization of the CA4+ partition with gadoteridol partition within the cartilage significantly (p < 0.05) improved the detection sensitivity for human osteoarthritic cartilage proteoglycan content, biomechanical properties, and overall condition (Mankin, Osteoarthritis Research Society International, and International Cartilage Repair Society grading systems). The dual energy technique combined with the dual contrast agent enables assessment of human articular cartilage proteoglycan content and biomechanical properties based on CA4+ partition determined using synchrotron microCT. Additionally, the dual contrast technique is not limited by the beam hardening artifact of conventional CT systems. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 38:563–573, 2020

Quantitative dual contrast photon-counting computed tomography for assessment of articular cartilage health

“…The combination of PCD-CT and CECT allows efficient and quantitative assessment of the key cartilage quality and properties, such as PG and water content, as well as detection of early PTOA. This is the first study to combine these two methods with human articular cartilage and the results obtained are in agreement with the previous studies using conventional EIDs [18][19][20][21] . The measured contrast agent partition profiles of the CA4+ and the gadoteridol (Fig.…”

“…Biomechanical indentation. Equilibrium and instantaneous moduli were determined for the samples in indentation geometry using a custom-made testing system 18,19,21,33 . A stress-relaxation protocol was implemented using a ramp strain rate of 100% per second with three compressive steps.…”

“…To enhance the capability of CECT-imaging, we developed a quantitative dual-energy CT (QDECT) technique that uses a mixture of non-ionic gadolinium-based gadoteridol and cationic iodinated CA4+ contrast agents [18][19][20][21] . The use of QDECT with the two contrast agents allows quantitative assessment of two important health reflecting properties of the articular cartilage, i.e., water and PG content.…”

“…In this study, we apply photon-counting detector computed tomography (PCD-CT) to the previously introduced dual contrast agent method [18][19][20][21] . We employ the two bin PCD-CT system with dual contrast agent method to study human articular cartilage.…”

Toward an “Ancient” Virtual World: Improvement Methods on X-ray CT Data Processing and Virtual Reconstruction of Fossil Skulls

“…All these virtual techniques are based on the 3D characterization of the object (e.g., skull, mandibles, or any other skeletal part preserved as a fossil or footprints and burrow casts) subject to analysis (Knaust, 2012;Kouraiss et al, 2019). This could be also done to digitize solely the external surface of the object (e.g., using laser scanning, modulated-light, structurelight surface scanning or photogrammetry) or to digitize both the external surface as well as the internal structures with XCT (Kouraiss et al, 2019) or synchrotron microtomography (SRµCT) (Sanchez et al, 2012;Davesne et al, 2019;Honkanen et al, 2020). Depending on the type of the object and the aim of the study, the resolution required will be different, and therefore, one type of tomography will be used.…”