https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 09 Jun 2026 18:30:08 GMT 2026-06-09T18:30:08Z http://hdl.handle.net/10985/18180 Reliable femoral frame construction based on MRI dedicated to muscles position follow-up. DUBOIS, Guillaume; BONNEAU, Dominique; LAFAGE, Virginie; SKALLI, Wafa; ROUCH, Philippe In vivo follow-up of muscle shape variation represents a challenge when evaluating muscle development due to disease or treatment. Recent developments in muscles reconstruction techniques indicate MRI as a clinical tool for the follow-up of the thigh muscles. The comparison of 3D muscles shape from two different sequences is not easy because there is no common frame. This study proposes an innovative method for the reconstruction of a reliable femoral frame based on the femoral head and both condyles centers. In order to robustify the definition of condylar spheres, an original method was developed to combine the estimation of diameters of both condyles from the lateral antero-posterior distance and the estimation of the spheres center from an optimization process. The influence of spacing between MR slices and of origin positions was studied. For all axes, the proposed method presented an angular error lower than 1° with spacing between slice of 10 mm and the optimal position of the origin was identified at 56 % of the distance between the femoral head center and the barycenter of both condyles. The high reliability of this method provides a robust frame for clinical follow-up based on MRI . Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/18180 2015-01-01T00:00:00Z DUBOIS, Guillaume BONNEAU, Dominique LAFAGE, Virginie SKALLI, Wafa ROUCH, Philippe In vivo follow-up of muscle shape variation represents a challenge when evaluating muscle development due to disease or treatment. Recent developments in muscles reconstruction techniques indicate MRI as a clinical tool for the follow-up of the thigh muscles. The comparison of 3D muscles shape from two different sequences is not easy because there is no common frame. This study proposes an innovative method for the reconstruction of a reliable femoral frame based on the femoral head and both condyles centers. In order to robustify the definition of condylar spheres, an original method was developed to combine the estimation of diameters of both condyles from the lateral antero-posterior distance and the estimation of the spheres center from an optimization process. The influence of spacing between MR slices and of origin positions was studied. For all axes, the proposed method presented an angular error lower than 1° with spacing between slice of 10 mm and the optimal position of the origin was identified at 56 % of the distance between the femoral head center and the barycenter of both condyles. The high reliability of this method provides a robust frame for clinical follow-up based on MRI . http://hdl.handle.net/10985/15820 A subject-specific biomechanical control model for the prediction of cervical spine muscle forces VAN DEN ABBEELE, Maxim; LI, Fan; POMERO, Vincent; BONNEAU, Dominique; SANDOZ, Baptiste; SKALLI, Wafa; LAPORTE, Sébastien Background: The aim of the present study is to propose a subject-specific biomechanical control model for the estimation of active cervical spine muscle forces. Methods: The proprioception-based regulation model developed by Pomero et al. (2004) for the lumbar spine was adapted to the cervical spine. The model assumption is that the control strategy drives muscular activation to maintain the spinal joint load below the physiological threshold, thus avoiding excessive intervertebral displacements. Model evaluation was based on the comparison with the results of two reference studies. The effect of the uncertainty on the main model input parameters on the predicted force pattern was assessed. The feasibility of building this subject-specific model was illustrated with a case study of one subject. Findings: The model muscle force predictions, although independent from EMG recordings, were consistent with the available literature, with mean differences of 20%. Spinal loads generally remained below the physiological thresholds. Moreover, the model behavior was found robust against the uncertainty on the muscle orientation, with a maximum coefficient of variation (CV) of 10%. Interpretation: After full validation, this model should offer a relevant and efficient tool for the biomechanical and clinical study of the cervical spine, which might improve the understanding of cervical spine disorders. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/15820 2018-01-01T00:00:00Z VAN DEN ABBEELE, Maxim LI, Fan POMERO, Vincent BONNEAU, Dominique SANDOZ, Baptiste SKALLI, Wafa LAPORTE, Sébastien Background: The aim of the present study is to propose a subject-specific biomechanical control model for the estimation of active cervical spine muscle forces. Methods: The proprioception-based regulation model developed by Pomero et al. (2004) for the lumbar spine was adapted to the cervical spine. The model assumption is that the control strategy drives muscular activation to maintain the spinal joint load below the physiological threshold, thus avoiding excessive intervertebral displacements. Model evaluation was based on the comparison with the results of two reference studies. The effect of the uncertainty on the main model input parameters on the predicted force pattern was assessed. The feasibility of building this subject-specific model was illustrated with a case study of one subject. Findings: The model muscle force predictions, although independent from EMG recordings, were consistent with the available literature, with mean differences of 20%. Spinal loads generally remained below the physiological thresholds. Moreover, the model behavior was found robust against the uncertainty on the muscle orientation, with a maximum coefficient of variation (CV) of 10%. Interpretation: After full validation, this model should offer a relevant and efficient tool for the biomechanical and clinical study of the cervical spine, which might improve the understanding of cervical spine disorders. http://hdl.handle.net/10985/18158 Muscle parameters estimation based on biplanar radiography DUBOIS, Guillaume; BONNEAU, Dominique; GENNISSON, Jean-Luc; SKALLI, Wafa; ROUCH, Philippe The evaluation of muscle and joint forces in vivo is still a challenge. Musculo-Skeletal (musculoskeletal) models are used to compute forces based on movement analysis. Most of them are built from a scaled-generic model based on cadaver measurements, which provides a low level of personalization, or from Magnetic Resonance Images, which provide a personalized model in lying position. This study proposed an original two steps method to access a subject-specific musculoskeletal model in 30 min, which is based solely on biplanar X-Rays. First, the subject-specific 3D geometry of bones and skin envelopes were reconstructed from biplanar X-Rays radiography. Then, 2200 corresponding control points were identified between a reference model and the subjectspecific X-Rays model. Finally, the shape of 21 lower limb muscles was estimated using a non-linear transformation between the control points in order to fit the muscle shape of the reference model to the X-Rays model. Twelfth musculo-skeletal models were reconstructed and compared to their reference. The muscle volume was not accurately estimated with a standard deviation (SD) ranging from 10 to 68%. However, this method provided an accurate estimation the muscle line of action with a SD of the length difference lower than 2% and a positioning error lower than 20 mm. The moment arm was also well estimated with SD lower than 15% for most muscle, which was significantly better than scaled-generic model for most muscle. This method open the way to a quick modeling method for gait analysis based on biplanar radiography. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/18158 2016-01-01T00:00:00Z DUBOIS, Guillaume BONNEAU, Dominique GENNISSON, Jean-Luc SKALLI, Wafa ROUCH, Philippe The evaluation of muscle and joint forces in vivo is still a challenge. Musculo-Skeletal (musculoskeletal) models are used to compute forces based on movement analysis. Most of them are built from a scaled-generic model based on cadaver measurements, which provides a low level of personalization, or from Magnetic Resonance Images, which provide a personalized model in lying position. This study proposed an original two steps method to access a subject-specific musculoskeletal model in 30 min, which is based solely on biplanar X-Rays. First, the subject-specific 3D geometry of bones and skin envelopes were reconstructed from biplanar X-Rays radiography. Then, 2200 corresponding control points were identified between a reference model and the subjectspecific X-Rays model. Finally, the shape of 21 lower limb muscles was estimated using a non-linear transformation between the control points in order to fit the muscle shape of the reference model to the X-Rays model. Twelfth musculo-skeletal models were reconstructed and compared to their reference. The muscle volume was not accurately estimated with a standard deviation (SD) ranging from 10 to 68%. However, this method provided an accurate estimation the muscle line of action with a SD of the length difference lower than 2% and a positioning error lower than 20 mm. The moment arm was also well estimated with SD lower than 15% for most muscle, which was significantly better than scaled-generic model for most muscle. This method open the way to a quick modeling method for gait analysis based on biplanar radiography. http://hdl.handle.net/10985/18182 Reliable Protocol for Shear Wave Elastography of Lower Limb Muscles at Rest and During Passive Stretching. DUBOIS, Guillaume; KHEIREDDINE, Walid; BONNEAU, Dominique; THOREUX, Patricia; TANTER, Mickael; GENNISSON, Jean-Luc; SKALLI, Wafa; ROUCH, Philippe; VERGARI, Claudio Development of shear wave elastography gave access to non-invasive muscle stiffness assessment in vivo. The aim of the present study was to define a measurement protocol to be used in clinical routine for quantifying the shear modulus of lower limb muscles. Four positions were defined to evaluate shear modulus in 10 healthy subjects: parallel to the fibers, in the anterior and posterior aspects of the lower limb, at rest and during passive stretching. Reliability was first evaluated on two muscles by three operators; these measurements were repeated six times. Then, measurement reliability was compared in 11 muscles by two operators; these measurements were repeated three times. Reproducibility of shear modulus was 0.48 kPa and repeatability was 0.41 kPa, with all muscles pooled. Position did not significantly influence reliability. Shear wave elastography appeared to be an appropriate and reliable tool to evaluate the shear modulus of lower limb muscles with the proposed protocol. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/18182 2015-01-01T00:00:00Z DUBOIS, Guillaume KHEIREDDINE, Walid BONNEAU, Dominique THOREUX, Patricia TANTER, Mickael GENNISSON, Jean-Luc SKALLI, Wafa ROUCH, Philippe VERGARI, Claudio Development of shear wave elastography gave access to non-invasive muscle stiffness assessment in vivo. The aim of the present study was to define a measurement protocol to be used in clinical routine for quantifying the shear modulus of lower limb muscles. Four positions were defined to evaluate shear modulus in 10 healthy subjects: parallel to the fibers, in the anterior and posterior aspects of the lower limb, at rest and during passive stretching. Reliability was first evaluated on two muscles by three operators; these measurements were repeated six times. Then, measurement reliability was compared in 11 muscles by two operators; these measurements were repeated three times. Reproducibility of shear modulus was 0.48 kPa and repeatability was 0.41 kPa, with all muscles pooled. Position did not significantly influence reliability. Shear wave elastography appeared to be an appropriate and reliable tool to evaluate the shear modulus of lower limb muscles with the proposed protocol. http://hdl.handle.net/10985/20228 Study on cervical muscle volume by means of three-dimensional reconstruction LI, Fan; LAVILLE, Aurélien; BONNEAU, Dominique; SKALLI, Wafa; LAPORTE, Sébastien Purpose To quantify the cervical muscle volume variation by means of three‐dimensional reconstruction from MRI images. Materials and Methods Sixteen subjects were scanned using a Philips MRI scanner, including 11 men and 5 women, aged from 23 to 33 years, weighting between 49–80 kg. The deformation of a parametric specific object method was used to develop three‐dimensional muscle models from contours on a small number of MRI images. Six subjects were reconstructed by two observers for evaluating the reliability by means of intraclass correlation coefficient (ICC). The results were also compared with in vivo measurement on a single specimen from a reference literature. The difference in left and right muscles volumes was assessed with a paired Wilcoxon signed rank test. Results The results showed good reliability by means of ICC study and were consistent with the in vivo specimen measurements. The left and right paired muscle volumes showed no significant difference. Interindividual variance was large that could reach 364 cm3, but the ratio of a given muscle volume to the total volume was less variable, always lower than 13%. The maximum cross sectional areas of cervical muscles varied greatly between individuals and the maximum values were mostly found at the C6–C7 level. Conclusion This study provides initial results which could be used as reference data for clinical evaluation and biomechanical model development. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/20228 2013-01-01T00:00:00Z LI, Fan LAVILLE, Aurélien BONNEAU, Dominique SKALLI, Wafa LAPORTE, Sébastien Purpose To quantify the cervical muscle volume variation by means of three‐dimensional reconstruction from MRI images. Materials and Methods Sixteen subjects were scanned using a Philips MRI scanner, including 11 men and 5 women, aged from 23 to 33 years, weighting between 49–80 kg. The deformation of a parametric specific object method was used to develop three‐dimensional muscle models from contours on a small number of MRI images. Six subjects were reconstructed by two observers for evaluating the reliability by means of intraclass correlation coefficient (ICC). The results were also compared with in vivo measurement on a single specimen from a reference literature. The difference in left and right muscles volumes was assessed with a paired Wilcoxon signed rank test. Results The results showed good reliability by means of ICC study and were consistent with the in vivo specimen measurements. The left and right paired muscle volumes showed no significant difference. Interindividual variance was large that could reach 364 cm3, but the ratio of a given muscle volume to the total volume was less variable, always lower than 13%. The maximum cross sectional areas of cervical muscles varied greatly between individuals and the maximum values were mostly found at the C6–C7 level. Conclusion This study provides initial results which could be used as reference data for clinical evaluation and biomechanical model development. http://hdl.handle.net/10985/20779 Subject-specific musculoskeletal model of the lower limb in a lying and standing position HAUSSELLE, Jerome; ASSI, Ayman; EL HELOU, Amine; JOLIVET, Erwan; DION, Elisabeth; BONNEAU, Dominique; SKALLI, Wafa; PILLET, Helene Accurate estimation of joint loads implies using subject-specific musculoskeletal models. Moreover, as the lines of action of the muscles are dictated by the soft tissues, which are in turn influenced by gravitational forces, we developed a method to build subject-specific models of the lower limb in a functional standing position. Bones and skin envelope were obtained in a standing position, whereas muscles and a set of bony landmarks were obtained from conventional magnetic resonance images in a lying position. These muscles were merged with the subject-specific skeletal model using a nonlinear transformation, taking into account soft tissue movements and gravitational effects. Seven asymptomatic lower limbs were modelled using this method, and results showed realistic deformations. Comparing the subject-specific skeletal model to a scaled reference model rendered differences in terms of muscle length up to 4% and in terms of moment arm for adductor muscles up to 30%. These preliminary findings enlightened the importance of subject-specific modelling in a functional position. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/20779 2012-01-01T00:00:00Z HAUSSELLE, Jerome ASSI, Ayman EL HELOU, Amine JOLIVET, Erwan DION, Elisabeth BONNEAU, Dominique SKALLI, Wafa PILLET, Helene Accurate estimation of joint loads implies using subject-specific musculoskeletal models. Moreover, as the lines of action of the muscles are dictated by the soft tissues, which are in turn influenced by gravitational forces, we developed a method to build subject-specific models of the lower limb in a functional standing position. Bones and skin envelope were obtained in a standing position, whereas muscles and a set of bony landmarks were obtained from conventional magnetic resonance images in a lying position. These muscles were merged with the subject-specific skeletal model using a nonlinear transformation, taking into account soft tissue movements and gravitational effects. Seven asymptomatic lower limbs were modelled using this method, and results showed realistic deformations. Comparing the subject-specific skeletal model to a scaled reference model rendered differences in terms of muscle length up to 4% and in terms of moment arm for adductor muscles up to 30%. These preliminary findings enlightened the importance of subject-specific modelling in a functional position. http://hdl.handle.net/10985/8274 Intervertebral disc characterization by shear wave elastography: an in-vitro preliminary study VERGARI, Claudio; ROUCH, Philippe; DUBOIS, Guillaume; BONNEAU, Dominique; DUBOUSSET, Jean; TANTER, Mickael; GENNISSON, Jean-Luc; SKALLI, Wafa Patient-specific numerical simulation of the spine is a useful tool both in clinic and research. While geometrical personalization of the spine is no more an issue, thanks to recent technological advances, non-invasive personalization of soft tissue’s mechanical properties remains a challenge. Ultrasound elastography is a relatively recent measurement technique allowing the evaluation of soft tissue’s elastic modulus through the measurement of shear wave speed (SWS). The aim of this study was to determine the feasibility of elastographic measurements in intervertebral disc (IVD). An in-vitro approach was chosen to test the hypothesis that SWS can be used to evaluate IVD mechanical properties and to assess measurement repeatability. Eleven oxtail IVDs were tested in compression to determine their stiffness and apparent elastic modulus at rest and at 400 N. Elastographic measurements were performed in these two conditions and compared to these mechanical parameters. The protocol was repeated six times to determine elastographic measurement repeatability. Average SWS over all samples was 5.3 ± 1.0 m/s, with a repeatability of 7 % at rest and 4.6 % at 400 N; stiffness and apparent elastic modulus were 266.3 ± 70.5 N/mm and 5.4 ± 1.1 MPa at rest, respectively, while at 400 N they were 781.0 ± 153.8 N/mm and 13.2 ± 2.4 MPa. Correlations were found between elastographic measurements and IVD mechanical properties; these preliminary results are promising for further in-vivo application. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8274 2014-01-01T00:00:00Z VERGARI, Claudio ROUCH, Philippe DUBOIS, Guillaume BONNEAU, Dominique DUBOUSSET, Jean TANTER, Mickael GENNISSON, Jean-Luc SKALLI, Wafa Patient-specific numerical simulation of the spine is a useful tool both in clinic and research. While geometrical personalization of the spine is no more an issue, thanks to recent technological advances, non-invasive personalization of soft tissue’s mechanical properties remains a challenge. Ultrasound elastography is a relatively recent measurement technique allowing the evaluation of soft tissue’s elastic modulus through the measurement of shear wave speed (SWS). The aim of this study was to determine the feasibility of elastographic measurements in intervertebral disc (IVD). An in-vitro approach was chosen to test the hypothesis that SWS can be used to evaluate IVD mechanical properties and to assess measurement repeatability. Eleven oxtail IVDs were tested in compression to determine their stiffness and apparent elastic modulus at rest and at 400 N. Elastographic measurements were performed in these two conditions and compared to these mechanical parameters. The protocol was repeated six times to determine elastographic measurement repeatability. Average SWS over all samples was 5.3 ± 1.0 m/s, with a repeatability of 7 % at rest and 4.6 % at 400 N; stiffness and apparent elastic modulus were 266.3 ± 70.5 N/mm and 5.4 ± 1.1 MPa at rest, respectively, while at 400 N they were 781.0 ± 153.8 N/mm and 13.2 ± 2.4 MPa. Correlations were found between elastographic measurements and IVD mechanical properties; these preliminary results are promising for further in-vivo application. http://hdl.handle.net/10985/8795 Non-invasive biomechanical characterization of intervertebral discs by shear wave ultrasound elastography: a feasibility study DUBOIS, Guillaume; BONNEAU, Dominique; DUBOUSSET, Jean; TANTER, Mickael; GENNISSON, Jean-Luc; ROUCH, Philippe; VERGARI, Claudio Objectives Although magnetic resonance is widely spread to assess qualitatively disc morphology, a simple method to determine reliably intervertebral disc status is still lacking. Shear wave elastography is a novel technique that allows quantitative evaluation of soft-tissues’ mechanical properties. The aim of this study was to assess preliminary the feasibility and reliability of mechanical characterization of cervical intervertebral discs by elastography and to provide first reference values for asymptomatic subjects. Methods Elastographic measurements were performed to determine shear wave speed (SWS) in C6-C7 or C7-T1 disc of 47 subjects; repeatability and inter-operator reproducibility were assessed. Results Global average shear wave speed (SWS) was 3.0 ± 0.4 m/s; measurement repeatability and inter-user reproducibility were 7 and 10 %, respectively. SWS was correlated with both subject’s age (p = 1.3 × 10−5) and body mass index (p = 0.008). Conclusions Shear wave elastography in intervertebral discs proved reliable and allowed stratification of subjects according to age and BMI. Applications could be relevant, for instance, in early detection of disc degeneration or in follow-up after trauma; these results open the way to larger cohort studies to define the place of this technique in routine intervertebral disc assessment. Key Points • A simple method to obtain objectively intervertebral disc status is still lacking • Shear wave elastography was applied in vivo to assess intervertebral discs • Elastography showed promising results in biomechanical disc evaluation • Elastography could be relevant in clinical routine for intervertebral disc assessment Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8795 2014-01-01T00:00:00Z DUBOIS, Guillaume BONNEAU, Dominique DUBOUSSET, Jean TANTER, Mickael GENNISSON, Jean-Luc ROUCH, Philippe VERGARI, Claudio Objectives Although magnetic resonance is widely spread to assess qualitatively disc morphology, a simple method to determine reliably intervertebral disc status is still lacking. Shear wave elastography is a novel technique that allows quantitative evaluation of soft-tissues’ mechanical properties. The aim of this study was to assess preliminary the feasibility and reliability of mechanical characterization of cervical intervertebral discs by elastography and to provide first reference values for asymptomatic subjects. Methods Elastographic measurements were performed to determine shear wave speed (SWS) in C6-C7 or C7-T1 disc of 47 subjects; repeatability and inter-operator reproducibility were assessed. Results Global average shear wave speed (SWS) was 3.0 ± 0.4 m/s; measurement repeatability and inter-user reproducibility were 7 and 10 %, respectively. SWS was correlated with both subject’s age (p = 1.3 × 10−5) and body mass index (p = 0.008). Conclusions Shear wave elastography in intervertebral discs proved reliable and allowed stratification of subjects according to age and BMI. Applications could be relevant, for instance, in early detection of disc degeneration or in follow-up after trauma; these results open the way to larger cohort studies to define the place of this technique in routine intervertebral disc assessment. Key Points • A simple method to obtain objectively intervertebral disc status is still lacking • Shear wave elastography was applied in vivo to assess intervertebral discs • Elastography showed promising results in biomechanical disc evaluation • Elastography could be relevant in clinical routine for intervertebral disc assessment