CARTILAGE THICKNESS MEASUREMENTS FROM PHOTO-COUNTING SPECTRAL COMPUTED TOMOGRAPHY IMAGES COMPARED WITH SYNCHROTRON RADIATION COMPUTED TOMOGRAPHY

International audienceImaging modalities which contribute to diagnosis, follow up and a better understanding of osteoarthritis are radiography, Magnetic Resonance Imaging (MRI), X-ray Computed tomography (CT), ultrasound, dual energy absorptiometry and positron emission tomography. Among these modalities, radiography is still the reference method to follow the cartilage impairment in osteoarthritis but only MRI and CT can provide three-dimensional images, MRI being more classically used in both clinical surveys and routine to visualize cartilage due to high contrast. Based on 3D MRI sequences, it is possible to perform 3D morphological maps for quantitative cartilage volume and thickness measurements. The best isotropic images that can be achieved with a 3T MR scanner is 0.63x0.63x0.68mm3 [1] and 0.3x0.3x0.3mm3 with a 7T MR scanner [2]. A new modality called Photo-Counting Spectral Computed Tomography (PCSCT) emerged recently with as main advantages to increase the resolution, the signal to noise ratio and the contrast in soft tissue compare to energy-integrating detectors that are classically used in routine CT device. From this new approach, we have shown in a previous study the interest of PCSCT virtual monoenergetic images at 60 keV for cartilage imaging [3].Zhang P et al. Clinical validation of the use of prototype software for automatic cartilage segmetation to qiantify knee cartilage in volunteers. BMC Musculoskeletal Disord. 23:19, 2022Bangarter N et al. Quantitative techniques for musculoskeletal MRI at 7 T. Quant Imaging med Surg 6:715,2016Chappard C et al. Virtual monoenergetic images from photon-counting spectral computed tomography to assess knee osteoarthritis. Eur Radio Exp, 22,6 202