Étude en IRM à très haut champ (7 Tesla) et scanner de la texture osseuse trabéculaire vertébrale et fémorale ex-vivo à l’aide d’un nouveau logiciel de post traitement OleaSphère® : comparaison avec les paramètres biomécaniques et l’ostéodensitométrie

Design de l'étude : essais biomécaniques avec pièces vertébrales lombaires et analyse de textureIntroduction : les limites de la densité minérale osseuse (DMO) pour l'évaluation de l'ostéoporose et de la fragilité osseuse ont été reconnues et, actuellement, la définition de l'ostéoporose inclut l'altération de la qualité osseuse. L'analyse de texture est un des outils utilisés pour évaluer la qualité des os.Objectif : le but de l'étude était de déterminer si les paramètres de texture calculés sur IRM à très haut champ (7 tesla) et tomodensitométrie étaient corrélés aux paramètres biomécaniques et à la DMO, évalués respectivement par des essais mécaniques de compression et DXA.Méthodes : la DMO de vingt-quatre vertèbres (L2, L3, L4) de huit cadavres a été étudiée à l'aide de DXA. Dix-neuf paramètres de texture ont été calculés pour chaque vertèbre en l'IRM et en tomodensitométrie. La reproductibilité inter-observateur a été établie grâce à deux opérateurs. Ensuite, toutes les pièces ont subi des essais mécaniques de compression jusqu'à fracture. La force à rupture et la contrainte correspondantes ont été calculées.Résultats : la force à rupture était significativement corrélée avec Fisrt-order Energy, Co-occurrence Sum Average, Run length Low gray level run emphasis and Run length High gray level run emphasis dans le groupe tomodensitométrie, et avec Co-occurrence Correlation en IRM transversale (p<0.05). La combinaison de Run length Low gray level run emphasis avec la DMO améliore la prédiction de la contrainte à rupture d'un R2 ajusté = 0,3738 pour la DMO seule à un R2 ajusté = 0,5482 (p<0,05). La fiabilité inter-évaluateurs était modérée à bonne avec un ICC de 0,61 à 0,99.Conclusion : dans ces échantillons de vertèbres, quatre paramètres de texture mesurés avec le nouveau logiciel de texture Olea ont été corrélés avec la force à rupture et la contrainte en tomodensitométrie. La combinaison d'un paramètre de texture en tomodensitométrie avec la DMO a amélioré la performance de la prédiction de la contrainte à rupture par rapport à la DMO seule. Nos résultats suggèrent que les paramètres de texture fournissent des informations supplémentaires sur le risque de fracture vertébrale

Texture Parameters Measured by UHF-MRI and CT Scan Provide Information on Bone Quality in Addition to BMD: A Biomechanical Ex Vivo Study

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, and if the combination of texture parameters and areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry provided a better prediction of femoral failure than aBMD alone. The aBMD of 16 proximal femur ends from eight cadavers were investigated. Nineteen textural parameters were computed in three regions or volumes of interest for each specimen on UHF MRI and CT scan. Then, the corresponding failure load and failure stress were calculated thanks to mechanical compression test. aBMD was not correlated to failure load (R2 = 0.206) and stress (R2 = 0.153). The failure load was significantly correlated with ten parameters in the greater trochanter using UHF MRI, and with one parameter in the neck and the greater trochanter using CT scan. Eight parameters in the greater trochanter using UHF MRI combined with aBMD improved the failure load prediction, and seven parameters improved the failure stress prediction. Our results suggest that textural parameters provide additional information on the fracture risk of the proximal femur when aBMD is not contributive

Texture Parameters Measured by UHF-MRI and CT Scan Provide Information on Bone Quality in Addition to BMD: A Biomechanical Ex Vivo Study

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, and if the combination of texture parameters and areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry provided a better prediction of femoral failure than aBMD alone. The aBMD of 16 proximal femur ends from eight cadavers were investigated. Nineteen textural parameters were computed in three regions or volumes of interest for each specimen on UHF MRI and CT scan. Then, the corresponding failure load and failure stress were calculated thanks to mechanical compression test. aBMD was not correlated to failure load (R-2 = 0.206) and stress (R-2 = 0.153). The failure load was significantly correlated with ten parameters in the greater trochanter using UHF MRI, and with one parameter in the neck and the greater trochanter using CT scan. Eight parameters in the greater trochanter using UHF MRI combined with aBMD improved the failure load prediction, and seven parameters improved the failure stress prediction. Our results suggest that textural parameters provide additional information on the fracture risk of the proximal femur when aBMD is not contributive

Texture Parameters Measured by UHF-MRI and CT Scan Provide Information on Bone Quality in Addition to BMD: A Biomechanical Ex Vivo Study

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, and if the combination of texture parameters and areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry provided a better prediction of femoral failure than aBMD alone. The aBMD of 16 proximal femur ends from eight cadavers were investigated. Nineteen textural parameters were computed in three regions or volumes of interest for each specimen on UHF MRI and CT scan. Then, the corresponding failure load and failure stress were calculated thanks to mechanical compression test. aBMD was not correlated to failure load (R-2 = 0.206) and stress (R-2 = 0.153). The failure load was significantly correlated with ten parameters in the greater trochanter using UHF MRI, and with one parameter in the neck and the greater trochanter using CT scan. Eight parameters in the greater trochanter using UHF MRI combined with aBMD improved the failure load prediction, and seven parameters improved the failure stress prediction. Our results suggest that textural parameters provide additional information on the fracture risk of the proximal femur when aBMD is not contributive