1

LEA

ULtrasound based Assessment of Bone (ULAB)

Project 2012-2015

� Laboratoire d’Imagerie Paramétrique (LIP) UMR 7623, Université Pierre et

Marie Curie, Paris, France � Quantitative Bioacoustic Microscopy group (Q-BAM) of Julius-Wolff-Institut

(JWI) at Charité-Universitätsmedizin Berlin, Germany � Section Biomedical Imaging at Universitätsklinikum Schleswig-Holstein

(UKSH), Kiel, Germany

2

Summary LEA ULAB (ultrasound based Assessment of Bone) has been created in 2008 jointly by CNRS (LIP UMR 7623, Paris), Charité-Universitätsmedizin Berlin and Universitätsklinikum Schleswig-Holstein (UKSH), Kiel. During the first four-year term, the LEA ULAB has been very active in promoting (i) young researchers exchange between the three partners, (ii) specimens and data exchange and (iii) experimental and modeling facilities sharing. This has resulted in 15 co-signed papers, multiple invitations to present the LEA work at major conferences, and a book edited by Springer in 2011. ULAB now holds a leading international position in the field of application of quantitative bone ultrasound to assess skeletal health and to improve fracture risk assessment for osteoporosis by coordinating and combining interdisciplinary basic research with development of novel instrumentation and clinical evaluation of multisite, multiscale, & multiparametric US-based technologies. Besides the share of research facilities, technologies, samples and data, major efforts of the ULAB are to provide efficient training from the undergraduate to the PostDoc levels and to initiate international research collaborations of young researchers by research exchanges, and co-supervision of graduate students. This comprises joint international projects, student and PostDoc exchange, joint doctoral programs with European collaborators, and the initiation of the biannual conference series “European Symposium on Ultrasonic Characterization of Bone (ESUCB)”. Pathologies of the musculoskeletal system have an increasing impact on the health of the ageing population. Costs associated with these diseases are an ascending burden of expenditure in the European health system. Although different kinds of invasive and noninvasive therapies exist, a widespread application of these therapies would overburden the health system. Moreover, their usages are not in the interest of patients with a low risk for severe events like bone fractures or cartilage degeneration. Therefore, a crucial point is the identification of high risk patients which are expected to profit from a specific therapy. Indeed, urgent scientific developments in early diagnostics and treatment of osteoporosis, are of critical importance in order to manage the future health challenge successfully. The partners are working on the development and clinical translation of novel ultrasound methods to assess bone strength and fracture risk. Ultrasound (US) is an advantageous method for the non-invasive, non-ionizing, in-vivo assessment of relevant bone properties (i.e. structure and elasticity), which cannot be achieved by radiological methods, e.g. DXA and computed tomography. Ultrasound based stand-alone approaches, the combination of different ultrasound methods or the combination of ultrasound methods with radiological readings and other risk assessment tools are anticipated to enhance the early diagnostic opportunities, particularly, to achieve a better discrimination between high and low risk patients. Here, the theoretical and experimental experience and know-how in bone ultrasound will be helpful to foster further development steps for a successful introduction of US as a diagnostic tool. The three partners within LEA (11.5 full time researchers, including Phd and post-doc) will combine their efforts to develop a common research program along three main axes: (a) Modeling, (b) multiscale/multiphysics investigations of bone properties, (c) Instrumentation and in vivo clinical measurements. The work may lead to : (a) advanced bone measuring US modalities ; (b) the progression of our fundamental understanding on how various aspects of bone affect stiffness and toughness ; (c) innovative ultrasound-based technologies to enhance skeletal status assessment and improve fracture risk prediction. Finally, such studies may ultimately impact the medical field by the establishment of ultrasound measurement strategies to assess specific bone characteristics to early detect patient at risk or monitor therapies. More specifically, understanding how micro- and nano-scale features are related to mechanical properties and knowing the link between stiffness and toughness may help to better establish QUS modalities as a diagnostic tool for bone diseases.

3

I - Historical review & achievements (2008-2011)

Bone pathologies have an increasing impact on the health of the ageing population. Costs associated with these diseases are an ascending burden of expenditure in the European health system. Although different kinds of therapies exist, a widespread application of these therapies would overburden the health system. Moreover, their usages are not in the interest of patients with a low risk for severe events like bone fractures. Therefore, a crucial point is the identification of high risk patients which are expected to profit from a specific therapy. Indeed, urgent scientific developments in early diagnostics and treatment of musculoskeletal diseases, such as osteoporosis are of critical importance in order to manage the future health challenge successfully.

1. Objectives to be achieved

Ultrasound (US) is an advantageous method for the non-invasive, non-ionizing, in-vivo assessment of relevant bone properties (i.e. structure and elasticity), which cannot be achieved by radiological methods, e.g. DXA and computed tomography. Ultrasound based stand-alone approaches, the combination of different ultrasound methods or the combination of ultrasound methods with radiological readings and other risk assessment tools are anticipated to enhance the early diagnostic opportunities, particularly, to achieve a better discrimination between high and low risk patients. Here, the theoretical and experimental experience and know-how in bone ultrasound will be helpful to foster further development steps for a successful introduction of US as a diagnostic tool.

In 2005 the German partners have established together with one French laboratory (LIP) the French-German network “Ultrasound assessment of bone strength from the tissue level to the organ level“, which resulted in the foundation of the European Associated Laboratory “Ultrasound Based Assessment of Bone – ULAB” in 2008.

The aim of the LEA is to integrate the broad and complementary expertise in basic science, instrumentation development and numerical modeling with the close link to medical research centres, which allows preclinical and clinical trials in multicenter studies. Besides ultrasound, the LEA partners provide access to and expertise in several other imaging modalities, e.g. synchrotron radiation micro computed tomography (Dr. F. Peyrin ESRF-CREATIS UMR5220) and spectroscopy (Dr. A. Gourrier, ESRF-Laboratoire de Physique des Solides UMR8502), multiple-resolution CT and DXA (H. Petite, Biomécanique et biomatériaux ostéo-articulaires UMR7052) and mechanical testing (Pr. D. Mitton, Laboratoire de Biomécanique et Mécanique des Chocs UMR_T 9406 IFSTTAR).

The goal of this LEA is to bundle the activities in France and Germany under one roof and by that to allow multidirectional collaborations and coordinated research and scientific education, which is essential to counterbalance the much larger communities working on other topics of medical physics,. The main field of research in the LEA will be the development and application of ultrasound methods for the distinct assessment of bone properties related to biomechanical competence. Through the broad expertise of the partners a wide range of in-vivo applicable quantitative ultrasound methods will be complemented by other in-vivo imaging methods, e.g. acoustic microscopy, µCT and DXA. Numerical sound propagation and mechanical modeling will be used to bridge experimental and clinical data with multi-scale tissue models. The second objective is to support scientific education in the field of ultrasound technologies by the establishment of structures that allow researchers from the undergraduate level to the PostDoc level easy access to research facilities through research practical, short to intermediate research exchanges, joint supervision of master and PhD theses, and the organization of workshops and Summer Schools.

2. Research management experience in coordinating i nternational projects

The two German applicants, i.e. Quantitative Bioacoustic Microscopy group (Q-BAM) of Julius-Wolff-Institut (JWI) at Charité-Universitätsmedizin Berlin and the Section Biomedical Imaging at Universitätsklinikum Schleswig-Holstein (UKSH) have a long history of concerted networking in research on bone and cartilage. Together with Laboratoire d’Imagerie Paramétrique (LIP) at Université Pierre & Marie Curie (UMPC) and CNRS the ULAB was founded in 2008. ULAB now holds a leading international position in the field of application of quantitative bone ultrasound to assess skeletal health and to improve fracture risk assessment for osteoporosis by coordinating and combining interdisciplinary basic research with development of novel instrumentation and clinical evaluation of multisite, multiscale, & multiparametric US-based technologies. Besides the share of research facilities, technologies, samples and data, major efforts of the ULAB are to provide efficient training from the undergraduate to the PostDoc levels and to initiate international research collaborations of

4

young researchers by research exchanges, and co-supervision of graduate students. A list of cooperative projects is summarized in Table 1. This comprises joint international projects, student and PostDoc exchange, joint doctoral programs with European collaborators, and the initiation of the biannual conference series “European Symposium on Ultrasonic Characterization of Bone (ESUCB)”.

Table 1: Previous concerted research actions Time Partner Title 2002-2003 Q-BAM, LIP PROCOPE: Quantitative acoustic microscopy (25 MHz -

2 GHz) of articular cartilage and bone

2003-2006 UKSH, LIP, Sulzer Innotech Femur Ultrasound Scanner (FEMUS), 5th EU Framework Program

2005-2007 UKSH, Q-BAM, LIP French-German network (Programme de Recherche en Réseau-P2R, 2005-2007): “Ultrasound assessment of bone strength from the tissue level to the organ level”

2008-now Q-BAM, LIP “Multiscale structure-functional modeling of musculoskeletal mineralized tissues” in DFG SPP 1420

2008-now LIP, Q-BAM, UKSH LEA ULAB

Knowledge dissemination and writing common papers During the four-year term 2008-2011, LEA ULAB has resulted in 15 co-signed articles published in peer reviewed journals (Bone, Osteoporosis int, J Biomech, Ultrasound Med Biol, IEEE UFFC…), international conferences proceedings, one book edited by P. Laugier (Springer, 2011) and nearly 50 conference presentations and posters (mostly by PhD students and post-doc)

Below, as examples of our concerted actions are lis ted the meetings, student and researcher exchange in 2010-2011, and the list of co-signed pu blications

Meetings

As an example, we show the list of meetings 2010-20 11

Meeting in Paris 18-19 February2010

One day meeting in LIP with Kay Raum to study the opportunity to answer to the European 7Th FP followed by a one day meeting working for analyzing experimental data acquired in 2009 and preparing a publication. LEA bi-annual Meeting in Paris October 28-29,2010 (~25 attendees). This meeting is run avery two years in alternance with ESUCB (see below) Most of the staff from the three centers involved in LEA activities attended the meeting (3 participants from Kiel, 6 from Berlin, 12 from Paris) The meeting included a full day of scientific sessions with in-length discussions between partners aiming at defining the work plan for the future, student exchanges, coordination, etc…Three half-day focused workshops were organized for the students and young researchers : (i) finite-difference time-domain simulation, (ii) low frequency contact ultrasound measurements of effective mesoscopic anisotropic stiffness and (iii) scanning acoustic microscopy. The meeting was attended by the members of the steering committee (Dr. Françoise Peyrin, Prof Georg Schmitz, Prof Philippe Zysset). The report on the activities of the LEA was introduced by Pascal LAUGIER, Kay Raum, and Reinhard Barkman (PIs). It was followed by short scientific presentation by young researchers. The steering committee wrote a summary report which is annexed to this document. Meeting in Darmstadt : 10-13 January 2011 Multiscale structure-functional modeling of musculoskeletal mineralized tissues - SPP1420 DFG-funded project (PI: Prof. Kay RAUM) Two senior researchers from LIP, Paris (Q. Grimal & P. Laugier) and one PhD student (M. Mouchet) attended the SPP1420 meeting together with the principal investigator (K. Raum, Q-BAM, Berlin, Germany) and other associated co-investigators from Germany and Austria. The working program and tasks coordination among partners and proposal renewal have been discussed in length during the meeting. Internships of PhD involved in the project have been

5

scheduled for 2011 to achieve the goals of the project:: students (German students will come to Paris, French PhD students will go to Berlin). Meeting in Hamburg : 23 february 2011 This meeting initially scheduled for December 2, 2010, was postponed due to bad weather conditions over Northern Europe and air traffic disruption. The meeting was postponed for early 2011, but will still be supported on the 2010 budget. P Laugier and Q Grimal (LIP) will meet with C-C Glüer and R Barkmann (Kiel) for a one day meeting during which future concerted investigations of cortical bone and femoral neck will be discussed with emphasis on technology and clinical transfer. The objective is to anticipate future actions beyond the 4-year term of LEA and prepare common grant proposals such as European Marie Curie Network, LEA renewal or extension. 4th European symposium on Ultrasonic Characterization of Bone, Jyväskylä, Finland Attendants : all An open symposium run every two years, all LEA active researchers are attending plus external researchers from Europe, North America and Asia This meeting is run every two years. student and researcher exchange (2010) Time Who What: where 2009 Daniel Rohrbach (Q-BAM) PhD research visit, 12 weeks (LIP) 2010 Daniel Rohrbach (Q-BAM) PhD research visit, 1 week (UKSH) 2010 Julien Grondin (LIP) PhD research visit, 4 week (UKSH) 2010 Mathilde mouchet (LIP) Ph.D research visit , 2 weeks (LIP) 2010 Quentin Grimal (LIP) PostDoc research visit, 1 week (Q-BAM) 2010 Quentin Grimal (LIP) PostDoc research visit, 1 week (UKSH) 2010 Janne Karjalainen Ph.D research visit , 12 weeks (LIP) 2010 Mathilde mouchet (LIP) Ph.D research visit , 2 weeks (LIP) 2011 Kerstin Rohde (UKSH) Master research visit, 0.5 weeks (Q-BAM) 2011 Ferenc Lajos Molnár (Q-BAM) Ph.D research visit , 2 weeks (LIP) 2011 Pascal Dargent (LIP) Engineer research visit 1 week (Q-BAM) 3. Common publications and communications 2008-2011 All the references listed below associate co-authors from at least two partners of the network. Other articles and conference papers originating from a single group are not listed here. 3.1 Peer reviewed journals & book chapters

[1] Q Grimal, K Raum, A Gerish and Laugier. Derivation of the mesoscopic elasticity tensor of a

cortical bone sample from quantitative impedance images at the micron scale. Comput

Methods Biomech Biomed Engin, Apr;11(2):147-57, 2008.

[2] S. Dencks, R. Barkmann, F. Padilla, P. Laugier, G. Schmitz, C.-C. Glüer. Model-based estimation

of Quantitative Ultrasound variables at the proximal femur. IEEE Trans Ultrason Ferroelec Freq

Contr. 55(6),1304-1315, 2008

[3] R. Barkmann , P. Laugier , U. Moser , S. Dencks , M. Klausner , F. Padilla , G. Haiat , M.Heller , C.-

C. Glüer. A Device for In vivo Measurements of Quantitative Ultrasound Variables at the

Human Proximal Femur. IEEE Trans Ultrason Ferroelec Freq Contr, 55(6), 1197-1204, 2008

[4] R Barkmann, P. Laugier, U Moser, S Dencks, M Klausner, F Padilla, G Haiat, M Heller and C.-C.

Glüer In vivo measurments of ultrasound transmission through the human proximal femur.

Ultrasound Med Biol, 34(7):1186-90, 2008.

[5] A Saïed, K Raum, I Leguerney, P. Laugier. Spatial distribution of acoustic impedance assessed by

scanning acoustic microscopy (50 MHz) and its relation to porosity in human cortical bone.

Bone, 43(1):187-94, 2008.

6

[6] F Rupin, A Saïed, D Dalmas, F Peyrin, S Haupert, K Raum, E Barthel, G Boivin, P. Laugier.

Assessment of Microelastic Properties of Bone Using Scanning Acoustic Microscopy : a Face-to-

Face Comparison with Nanoindentation. Japenese J Applied Phys, 07GK01-1-8, 2009

[7] R. Barkmann, S. Dencks, P. Laugier, F. Padilla, K. Brixen, J. Ryg, A. Seekamp, L. Mahlke, A.

Bremer, M. Heller, C. C. Glüer. Femur Ultrasound (FemUS) – first clinical results on hip fracture

discrimination and estimation of femoral BMD. Osteoporos Int, 21(6), 969-76,2010.

[8] F Rupin, D Bossis, L Vico, F Peyrin, K Raum, P. Laugier and A Saied. Adaptive remodeling of

trabecular bone in response to cyclic mechanical loading : an acoustic microscopy study.

Ultrasound Med Biol, 36(6), 999-1007, 2010.

[9] K Raum, D Rohrbach, P. Laugier, C-C. Glüer, R Barkmann. Bone quality beyond bone mineral

density – new diagnostic perspectives by quantitative ultrasound. Osteologie, 19(3), 217-224,

2010.

[10] Q. Grimal, G. Rus, W. Parnell, and P. Laugier. A two-parameters model of the effective elastic

tensor for cortical bone. J Biomech 44(8):1621-5, 2011.

[11] K Raum, Q Grimal, A Gerisch, P. Laugier. Multiscale structure-functional modeling of lamellar

bone - Proceedings of Meetings on Acoustics. POMA 9, 020005, 2011. INVITED PAPER.

[12] Q Grimal, K Raum, A Gerisch, P. Laugier. A determination of the minimum sizes of

representative volume elements for the prediction of cortical bone elastic properties. Biomech

Model Mechanobiol. In press

[13] M Granke, Q Grimal, A Saïed, P Nauleau, F Peyrin, P Laugier. Changes in porosity are the major

determinant of the variations of cortical bone elasticity at the millimeter scale in aged women.

Bone, in press

[14] D Rohrbach, S Lakshmanan, F Peyrin, M Langer, A Gerisch; Q Grimal, P Laugier, K Raum. Spatial

distribution of microscale properties in human femoral cortical bone. Submitted to J Biomech,

July 2011

[15] Rohrbach D, Grondin J., Grimal Q, Laugier P, Barkmann R, Raum K. Evidence based numerical

ultrasound simulations at the human femoral neck. Submitted to J. Biomech

3.2 Book chapters and Edition

Book edited by P. Laugier : Bone QUS. Eds. P. Laugier and G. Haiat. Springer, London. 2010

Including 5 chapters from LEA partners :

[1] Laugier P, Quantitative ultrasound instrumentation for bone in vivo characterization pp.47-72

[2] Raum K., Microscopic elastic properties, pp. 409-440.

[3] Barkmann R, Glüer CC. Clinical applications. pp. 73-82

[4] Talmant M, Foiret J, Minonzio J-G. Guided waves in cortical bone. Pp147-180

[5] Bossy E, Grimal Q. Numerical methods for ultrasonic bone characterization. pp. 181-228

Plus 2 other chapters

[6] K Raum, Q Grimal, P Zysset, A Gerisch, P Laugier Multiscale elastic imaging of mineralized

tissues. To be published in "Acoustic Wave", InTech Academic Publisher, ISBN: 978-953-307-

246-3.

[7] A. Saïed, M. Mouchet, K. Raum, P. Laugier. Quantitative acoustic scanning microscopy of bone.

To be published in "Scanning acoustic microscopy", Ed by R. Maev, Wiley Publisher.

3.3 Proceedings of International Conferences

[1] F Rupin, A Saïed, D Dalmas, F Peyrin, K Raum, E Barthel, G Boivin, P Laugier.

Comparison

between microelastic bone properties assessed by scanning acoustic microscopy and

nanoindentation. IEEE Ultrasonic Symposium, Beijing, China, November 2-5, 2008. Eds SC

Schneider, M Levy, BR McAvoy, IEEE, Piscataway, NJ, USA.

7

[2] K. Raum, A. Gerish, Q. Grimal, P. Laugier. Insight into the structure-function relationship of the

bone lamellar unit through finite element modelling based on high-frequency SAM data.

Proceedings of the World Congress on Medical physics and Biomedical Engineering, Sept 7-12,

2009, Munich, Germany.

[3] K Raum, Q Grimal, A Gerisch, P. Laugier. ”Listen to” bone quality: How ultrasound helps to

reveal microstructure and elastic function in bone. Lay paper presented at Acoustical Soc. Am.

(ASA) annual meeting , Baltimore, 18-23 April 2010.

3.4 Invited conferences and Seminars

[1] Riverside Research Institute, New York City, USA, February 19th, 2008

[2] Ultrasonic Imaging and Tissue Characterization (UITC), Arlington, VA May 14 - 16, 2008

[3] Ninth Annual Alberta Biomedical Engineering Conference, Banff, Alberta, Canada, October 24-26,

2008

[4] Bioengineering program Center. Université Doshisha . Kyoto, Japan, November 08, 2008

[5] AIUM (American Institute of Ultrasound in Medicine) New York, NY, USA,April 2-5, 2009

[6] 9th International workshop on Mathematical Methods in Scattering Theory and Biomedical

Enginneering, 9-11 october 2009, Patras, Greece

[7] Society for Industrial and Applied Mathematics (SIAM) Annual Meeting in Denver, Colorado, July

6-10, 2009.

[8] Tenth US National Congress on Computational Mechanics. July 16-19, 2009, Colombus, Ohio,

USA.

[9] Société Française de Recherche Orthopédique et Traumatologique. Paris, 9 nov 2009

[10] 3rd International Conference on the Development of Biomedical Engineering, Ho Chi Minh City,

Viet-Nam, January 2010

[11] Bioengineering program Center. Université Doshisha . Kyoto, Japan, November 16, 2009.

[12] 10ème Congrès Francais d'Acoustique Lyon, 13-16 Avril 2010.

[13] Biomedical Engineering, City College at the City University of New York, USA, 28 april 2010

[14] Biomedical Engineering and Radiology Columbia University, NY, USA, 30 april 2010

[15] Université Fédérale de Rio de Janiero, Brésil, 03 mars 2011

[16] Tissue Engineering and Regenerative Medicine International Society (TERMIS) 2011, June 7-10,

Granada, Spain

[17] University of Madrid, Spain, May 27, Spain

[18] European Symposium on Ultrasonic Characterization of Bone, Jyväskylä, Finland, 21-23 June,

2011

3.5 Communications

[1] R. Barkmann, S. Dencks, A. Bremer, P. Laugier, F. Padilla, K. Brixen, J. Ryg and C. C Glüer.

Estimation of femoral bone density from trabecular direct wave and cortical guided wave

ultrasound velocities measured at the proximal femur in vivo Acoustics’08, 29 juin-04 juillet,

Paris, France. J Acoust Soc Am, 123 (5), 3632, 2008.

[2] F Rupin, A Saied, D Dalmas, F Peyrin, E Barthel, G Boivin, P Laugier. Experimental determination

of Young’s modulus and Poisson ratio in cortical bone tissue using high resolution scanning

acoustic microscopy and nanoindentation. Acoustics’08, 29 juin-04 juillet, Paris, France. . J

Acoust Soc Am, 123 (5), 3785, 2008.

[3] R.Barkmann, S.Dencks, A.Bremer, P.Laugier, F.Padilla, K.Brixen, J.Ryg, C.-C.Glüer.

Femur

ultrasound (Femus) – a new method for the estimation of osteoporotic fracture risk? ECTS

2008 35th European symposium on Calcified Tissue, 24-28 may 2008, Barcelona, Spain.

8

[4] F Rupin, A Saïed, D Dalmas, F Peyrin, K Raum, E Barthe, G Boivin, P Laugier. Experimental

determination of Young’s modulus of cortical bone tissue using high resolution scanning

acoustic microscopy. Ultrasonic Imaging and Tissue Characterization (UITC), Arlington, VA, May

14 - 16, 2008.

[5] Q Grimal, K Raum, A Gerish and P Laugier. Continuum level elastic properties of cortical bone

derived from acoustic microscopy data. 18th International Bone Densitometry Workshop

(IBDW) June 15 - 19, 2008, Pugnochiuso Resort, Foggia, Italy.

[6] R. Barkmann, S. Dencks, P. Laugier, F. Padilla, K. Brixen, J. Ryg, C. C. Glüer. Femur Ultrasound

(FemUS) – improved fracture discrimination by evaluating direct and guided waves through

trabecular and cortical parts of the femur. 18th International Bone Densitometry Workshop

(IBDW) June 15 - 19, 2008, Pugnochiuso Resort, Foggia, Italy.

[7] F Rupin, A Saïed, D Dalmas, F Peyrin, K Raum, E Barthel, Georges Boivin, P Laugier. Assessment

of microelastic properties of bone using scanning acoustic microscopy : a face-to-face

comparison with nanoindentation 18th International Bone Densitometry Workshop (IBDW)

June 15 - 19, 2008, Pugnochiuso Resort, Foggia, Italy.

[8] F Rupin, A Saïed, D Dalmas, K Raum, E Barthel, P Laugier. Combination of high-resolution

scanning acoustic microscopy and nanoindentation to determine both Poisson’s ratio and

Young modulus of bone tissue. 18th International Bone Densitometry Workshop (IBDW) June

15 - 19, 2008, Pugnochiuso Resort, Foggia, Italy.

[9] P Laugier , F Rupin, D Dalmas, F Peyrin, K Raum, E Barthel, A Saïed. Assessment of microelastic

properties of bone using scanning acoustic microscopy : a face-to-face comparison with

nanoindentation, 29th Symposiumon Ultrasonics Electronics (USE), Sendaï, Japan, Nov 11-13,

2008.

[10] R. Barkmann, P. Laugier, F. Padilla, K. Brixen, J. Ryg, C.-C. Glüer. Discrimination of cervical and

trochanteric fractures by quantitative ultrasound of the femur (FemUS). Baltic Bone and

Cartilage Conference. Nyborg – Denmark, 23-26 August 2009.

[11] F Rupin, A Gourrier, M. Mouchet, K Raum, F Peyrin4, A Saied, P Laugier. Tissue acoustic

impedance of cortical bone is determined by nanostructural characteristics hydroxyapatite.

IEEE Ultrasonic Symposium, Rome, Italy, September 21-23, 2009.

[12] M Mouchet , A Gourrier, F Rupin, K Raum, F Peyrin, A Saïed, P Laugier. Variations of

nanostructural characteristics of mineral platelets across a human osteon are determined by

acoustic impedance modulation. 3rd

European Symposium on ultrasonic Characterization of

bone (Esucb). Bygdoscz, Pologne, 19-20 septembre.

[13] D RohrBach, R Barkmann, J Grondin, Q Grimal, P Laugier, K Raum. Towards a realistic model of

sound propagation through the femoral neck: I – Experimental assessment of microstructure

and matrix elasticity by 50-MHz scanning acoustic microscopy. 3rd

European Symposium on

ultrasonic Characterization of bone (Esucb). Bygdoscz, Pologne, 19-20 septembre.

[14] J Grondin, D RohrBach, K Raum, Reinhard Barkmann, P Laugier, Q Grimal. Towards a realistic

model sound propagation through the femoral neck: II – 0.5 MHz sound simulations based on

microelastic input data. 3rd

European Symposium on ultrasonic Characterization of bone

(Esucb). Bygdoscz, Pologne, 19-20 septembre.

[15] Q Grimal, J Grondin, D RohrBach, K Raum, R Barkmann, P Laugier, K Raum.Towards a realistic

model sound propagation through the femoral neck: III – Impact of structural and elastic

variations on the distribution of time of flight of the first arriving signal. 3rd

European

Symposium on ultrasonic Characterization of bone (Esucb). Bygdoscz, Pologne, 19-20

septembre.

[16] F Rupin, A Gourrier, A Saïed, F Peyrin, P Laugier. Influence of mineral nanostructural

characteristics on stiffness of bone evaluated by 1GHz-acoustic microscopy 34th International

Symposium on Ultrasonic Imaging and Tissue Characterization. June 10 – 12, 2009.

[17] F Rupin, A Saied, D Dalmas, F Peyrin, K Raum, E Barthel, Q Grimal, P Laugier. Cortical bone

microelasticity assessed with scanning acoustic microscopy. Tenth US National Congress on

Computational Mechanics. July 16-19, 2009, Colombus, Ohio, USA.

9

[18] Q. Grimal, K Raum, A Gerisch and P Laugier. Mesoscale effective elasticity of cortical bone

estimated based on high-resolution acoustic imaging. Tenth US National Congress on

Computational Mechanics. July 16-19, 2009, Colombus, Ohio, USA.

[19] Rupin F, Saied A, Raum K, Laugier P. Characterization of bone microstructure and microelastic

properties using acoustic microscopy.. AIUM (American Institute of Ultrasound in Medicine)

New York, NY, USA,April 2-5, 2009. INVITED COMMUNICATION

[20] M Mouchet , A Gourrier, F Rupin, K Raum, F Peyrin, A Saïed, P Laugier. 1 GHz-acoustic

microscopy : nanostructural characteristics of cortical bone determines elasticity at the micron

scale. 30th Symposiumon Ultrasonics Electronics (USE), Kyoto, Japan, Nov 18-20, 2009.

[21] M Mouchet, A Gourrier, K Raum, F Peyrin, A Saïed, P Laugier. Cortical bone microelasticity

assessed with scanning acoustic microscopy. Relationship to nanostructural characteristics

across a human osteon. 3rd

International conference on the development of biomedical

engineering in Vietnam. January 11 – 14th

, 2010.

[22] Raum, K., Grimal, Q., Gerisch, A., Laugier P. (invited), Multiscale structure-functional modeling

of lamellar bone, 159th Meeting of the Acoustical Society of America, Baltimore, 2010

[23] Raum, K. (invited), Microelastic imaging – a new technique for assessment of bone quality?

ultiscale structure-functional modeling of lamellar bone, ASBMR 2010, Toronto, 2010.

[24] Raum, K., Grimal, Q., Gerisch, A.(keynote lecture), Multiscale structure-functional modeling of

lamellar bone, ECCM, Paris, 2010

[25] Rohrbach, D., Grondin, J., Grimal, Q., Laugier, P., Evidence based numerical ultrasound

simulations at the human femoral neck, Biomedical Engineering, 55(s1), BMT 2010, Rostock,

Germany, 2010.

[26] Rohrbach D., Grondin J., Grimal Q., Laugier P, Barkmann R., Raum K.Evidence based numerical

ultrasound simulations at the human femoral neck. Osteology 2011.

[27] Grondin J, Grimal Q, Guérard S, Barkmann R, Glüer CC, Laugier P. In vitro evidence that the

circumferential wave guided by the femur cortical shell can be used to predict femur strength.

4rd

European Symposium on ultrasonic Characterization of bone (Esucb). Jyvaskyla, Finlande,

19-21 juin 2011.

[28] K Rohde, M Daugschies, Q Grimal, P. Laugier, C-C Glüer, R Barkmann. 2D simulations of the

impact of porosity and cortical thickness on the wave propagation at the inferior femoral neck

cortex. 4rd

European Symposium on ultrasonic Characterization of bone (Esucb). Jyvaskyla,

Finlande, 19-21 juin 2011.

[29] D. Rohrbach, S. Lakshmanan1, F. Peyrin , Max Langer,Alf Gerisch, Quentin Grimal, Pascal

Laugier, and K. Raum. Spatial distribution of tissue mineralization and anisotropic tissue elastic

constants in human femoral cortical bone. 4rd

European Symposium on ultrasonic

Characterization of bone (Esucb). Jyvaskyla, Finlande, 19-21 juin 2011.

[30] K. Raum; D. Rohrbach; P. Laugier; C.-C. Glüer; R. Barkmann. Knochenqualität jenseits von

Knochenmineraldichte – neue diagnostische Perspektiven mit quantitativem Ultraschall. Nicht-

invasive Diagnostik, Berlin, Germany, 26 May 2011.

10

I – Research Program : Quantitative Imaging of Functional Competence of Bone

1. Context – Significance of the research

Bones-related diseases represent one of the major worldwide health problems that will grow in importance in coming decades in EU as the population ages. Currently, X-ray techniques, considered as the gold standard for bone mass determination and fracture risk prediction, provides information about bone mass density (BMD) only, while it is now acknowledged that other factors contribute independently to bone strength. This result have triggered studies for alternative diagnostic modalities showing capacity to reach a complete quantitative assessment of bone quality beyond BMD. Among others, quantitative ultrasound (QUS) techniques have been developed in the past two decades to overcome these limitations. Ultrasound technologies are now integral part of the diagnostic armamentarium for skeletal status assessment. The significant growth of the QUS research field has been based on the affordability of this non-ionizing technology and the potential of ultrasound waves to probe bone quality features. Recently, the emphasis of innovative quantitative ultrasound (QUS) measurements basic research has shifted towards measurements of multiple propagation guided modes in cortical and subsequently a set of propagation velocities can be determined. Each guided wave velocity has its own relationship to stiffness coefficients, mass density and body geometrical properties. Developing accurate models is a key issue to solve the inverse problem, i.e., in determining bone properties such as cortical thickness, porosity or elastic properties at the individual level from ultrasound measurements. To further develop and validate inversion schemes, there is a clear call for better knowledge of the whole set of multiscale bon e properties .

General approach : ULAB research focuses on modelling, instrumentation and technology transfer. Ultrasound interactions with hard mineralised tissues (bone) are considered at different scales: from the nano/microscopic scale (using multiphysic investigations such as, e.g., scanning acoustic microscopy, nanoindentation or synchrotron radiation micro-computed tomography) to the organ level using in vivo quantification of bone properties. Models of ultrasound propagation and models of bone tissue are coupled to experimental data. Interaction mechanisms between ultrasound and bone tissue can be understood with laboratory experiments, theoretical calculations and computational models. Once the propagation models are validated, they can serve as a basis for the quantification of bone properties by model-based inverse methods.

Three main research axes will be developed :

1 - Modeling

2 - Multi-scale and multi-physic investigation of bone properties

3 - Instrumentation

2. Objectives – Scientific locks

2.1 - Modelling

The objectives are (i) to elucidate interaction mechanisms between elastic waves and bone structure; (ii) for propagation problems involving guided waves, to identify propagation modes

11

and determine their relationship to bone properties; (iii) to estimate the ultrasonic system response in different conditions (forward model); (iv) to establish inverse procedures to retrieve relevant bone properties from in vivo data; (v) to model the mechanical behaviour of bone.

Ultrasound propagation models with uncertainties. This research topic aims at developing a methodology to account for uncertainties in ultrasound propagation models and biomechanical models. We consider both uncertainties on geometry (shape, dimension and thickness of bones) and material properties (density, elasticity). Uncertainties are accounted for using probabilistic descriptions of the acoustical or mechanical problems. The responses of the stochastic models are investigated by means of Monte-Carlo simulations. The stochastic models are useful (i) to analyse the sensitivity of the response to the various parameters; (ii) to formulate robust inverse problems. Mechanical modelling of cortical bone.

Mechanical models of cortical bone elastic properties are a keystone to different ultrasonic applications developed in the laboratory. Their purpose is to relate some nanoscopic and microscopic features of bone tissue to its overall elastic properties, based on the principles of continuum mechanics. Models of bone tissue are multi-scale to account for the hierarchical organization of bone. They can be used (i) to relate the characteristics of the nanoscopic constituents of bone (mineral particles and collagen molecules) to the lamellar-level elastic properties, or (ii) to relate the porous network and the lamellar-level tissue elasticity to millimetre-scale properties. Realistic models of bone elastic properties must account for the organization of the bone matrix (orientation and content of mineral, quality of collagen) and the shape of the porous network. Elastic properties are anisotropic at different scales as a result of the composition and organisation of bone. Models are developed and validated based on experimental data obtained from multimodal experiments (RUS, SAM, mechanical testing, microtomography, etc.). Bone tissue models are helpful to set the bone mechanical properties in the computation codes of the ultrasonic propagation at the macroscopic scale, i.e., for the simulation of the QUS acoustic problems in vivo. Mechanical models can be run systematically to investigate the dependence of the various elastic constants on small-scales features (mineral content and orientation, porosity, etc.). When it comes to solving inverse problems based on in vivo ultrasound data, mechanical models can be used as a priori information to diminish the number of unknowns or define appropriate regularisation of the inverse problem algorithm.

Derivation of structure and tissue elasticity of mi neralized tissues from the nanoscale to the macroscale (within DFG Priority program “Bio mimetic Materials Research: SPP 1420, DFG Ra1380/7-2, Principal Investigator: Kay R aum, LEA co-principal investigator: Quentin Grimal) Musculoskeletal mineralized tissues (MMTs) are examples of natural materials achieving unique combinations of stiffness and strength. One of the striking features of MMTs is their ability to adapt to different functional demands by different structural arrangements of one common building block, the mineralized collagen fibril, at several levels of hierarchical organization. In the first funding period, we have applied multi-scale (from the nanoscale to the macroscale) and multimodal techniques to assess structure, composition, and elastic properties of various MMTs. Based on these data we have developed mathematical models and corresponding homogenization tools that allow to estimate the elastic properties at different length scales (microscale, mesoscale, macroscale). This enables to decouple characteristic structural features from material properties and hence to study their respective impacts on the elastic functional behaviour at each scale. Within the second funding period we focus on the further improvement of the experimental techniques at the micron and

12

submicron scales with the intention to increase the robustness of the experimental data. Moreover, we will systematically apply the models and computational tools to various MMTs and artificial hierarchical structures. Our ultimate goals are to provide public access to validated data of MMTs at different scales and to dedicated modelling tools as well as to infer generalized construction rules for the in-silico design of hierarchically structured (biomimetic) composites with desired elastic properties. This project combines multi-scale and multi-modal experimental assessment of tissue properties with mathematical modeling and micro-mechanical homogenization approaches from the nanoscale to the macroscale to describe the tissue elastic behavior of various MMTs. This “bottom-up approach” allows the decoupling of tissue composition, structure, and material properties at the various spatial scales involved and hence the systematic evaluation of their relative impacts on the macroscopic elastic function. Towards this goal, experimental data of heterogeneous elastic and structural parameters of MMTs at several length scales (from the centimeter to the nanometer scale) have been assessed (Preininger et al. 2011, Raum 2011, Raum et al. 2010, Rupin et al. 2009), [1]. In conjunction to the experimental data mathematical models at three length scales (i.e. nanoscale, microscale, and mesoscale) have been developed that allow the prediction of composite properties at the next hierarchy level (Grimal et al. 2011), [2]. The novelty of this project is that at each length scale the models have been coupled to and verified by experimental data. Therefore the suitability and limitations of the applied homogenization schemes could be verified. The developed numerical framework is not limited to MMTs, but will also be adapted to artificial (biomimetic) composite materials with a hierarchical structure.

Fig. 1: Illustration of the interlinked experimental and mathematical methods for the “Bottom-Up” approach. At each model step, the models are compared with experimental data (not all shown). Experimental data are indicated in black, models in blue and the combination of both in green.

2.2 - Multiscale experimental investigations of bo ne properties

13

The global aim of the project is a multiscale and multi-physics investigation of bone mechanical properties. One of the difficulties in approaching the mechanics of bone (a hierarchically structured material) is the vast number of characteristic length scales that must be taken into account. Scalable ultrasound is suitable for a multi-scale investigation of elastic properties of inhomogeneous materials such as bone.

Resonant ultrasound spectroscopy (RUS) It appears that a sensible first choice for our purpose is to look at the millimetre length scale, which corresponds to the wavelength of ultrasound waves used in vivo (frequency range 200kHz-1.5 MHz). Hence, a first specific goal of our work will be to measure the stiffness coefficients at this length scale. Toward this goal, our approach will be to implement resonant ultrasound spectroscopy measurements, an approach which has not been developed for bone yet, but is known to be the gold standard and the most precise method to quantitatively assess all the stiffness coefficients of single, low symmetry crystals from 1 cm to less than 1 mm in size. The major challenge includes methodology development of resonant ultrasound spectroscopy (RUS). Both “state-of-the art” and new technologies will then be used to assess stiffness and toughness (millimeter length scale), the micro- or nano-porosity (micrometer length scale) and the structure of the mineral and organic phases (nanometer length scale). This will involve carrying out measurements at multiple length scales using a multiphysic approach (RUS, mechanical tests, SR-µCT, SAXS, FTIRM, biochemistry) and investigating the links between stiffness and all the measured characteristics. This is an exciting, developing area of research with major potential benefits if techniques can be developed and links be established successfully. Advances in experimental techniques such as RUS will contribute to a better knowledge of bone properties related to bone biomechanical competence. The combination of multimodality and multiscale measurements will provide a unique set of data never obtained before. Elucidating the relationships between all measured variables is expected to contribute to the optimization and better acceptance of in vivo quantitative ultrasound modalities for bone testing. Scanning acoustic microscopy (SAM): Application to the investigation of elastic properties of bone at the tissue level. Scanning acoustic microscopy (SAM) enables to explore the micro-elastic properties of a material at a submillimetric resolution level. In the 50 MHz - 1 GHz frequency range, the technique allows the mapping of elastic properties of a heterogeneous material at a spatial resolution between 20 µm and 1 µm. The technique is well adapted to the assessment of bone that is a heterogeneous composite tissue characterized by a complex hierarchical organization. Our research aims at (i) developing methodologies of quantitative scanning acoustic microscopy; (ii) evaluating the micro-elastic properties of healthy or pathological bone tissue at different scales; and (iii) providing data to computational mechanical models of bone. The investigation of the determinant factors of the elastic properties of bone tissue is still a challenge and is therefore fundamental in this research. This, in particular, necessitates to relate acoustic measurements to bone material characteristics (ultrastructure, microstructure, composition, characteristics of collagen and HAP mineral crystals, etc.) as deduced from experiments with high-resolution modalities such as synchrotron radiation microtomography, small angle X-ray diffraction (sAXS), nanoindentation, Raman and Fourier transform infrared (FTIR) spectroscopy techniques, etc. The quantitative information derived from scanning acoustic microscopy can be used as input in computational mechanical models that are designed to predict the macroscopic biomechanical behavior of bone using the heterogeneous tissue micro-elastic characteristics obtained at the lower scale levels

2.3 - Instrumentation and in vivo clinical measurem ents

14

Technological developments aim at enhancing the potential of ultrasound techniques and facilitating their dissemination in clinical practice.

Guided waves measurements Different types of guided waves can propagate in cortical (or compact) bone. The analysis of these waves can provide information such as structural (cortical thickness, porosity) and material properties (elasticity, density). From the clinical perspective, this information is relevant for fracture risk assessment. This research topic is supported by innovative axial transmission technologies developed for the clinical use, associated with original signal processing methods (Singular value decomposition) allowing the extraction, identification and exploitation of several ultrasound propagation modes. Current research orientations include development of numerical models coupled to experimental data and solutions to inverse problems. Patents on (i) transducer arrays dedicated to long bone cortical shell evaluation using bi-directional transmission and (ii) signal processing using singular value decomposition (SVD) have been registered. A start-up company is currently being created to commercialize the clinical device using these technologies . In another project, we develop an ultrasonic method to assess in vivo the geometrical and mechanical properties of the cortical bone shell at the femoral neck using circumferential guided waves. The novelty of the project and its strength consist in using an ultrasonic transducer array, time-reversal techniques and advanced signal processing (e.g. DORT) to probe the femur. The experimental data are coupled to models in order to solve an 'inverse problem' to determine model parameters, i.e. elastic and geometric properties. This represents a significant breakthrough compared to the techniques developed in competitive teams worldwide, who mostly develop empirically-based approaches and single transducer technologies. In case of success the method will contribute to a more accurate definition of fracture risk. The assessment of material properties in vivo and t heir impact on fracture risk Whereas DXA based bone density almost exclusively depends on bone mass, ultrasound transmission variables are affected not only by the amount of bone but also by the microstructure and the material properties, most notably elasticity. Therefore, the technique has the potential to be used to assess bone properties beyond bone mass. Standard calcaneal QUS methods have been employed clinically for close to two decades and epidemiological studies have demonstrated that QUS variables predict fractures as well as DXA. Independent of this clinical field, in recent years research by biomedical ultrasound experts have made substantial progress in understanding the impact of bone properties on ultrasound propagation. Building on these advances we plan to investigate the use of QUS for the assessment of material properties in cortical and spongious bone. Spongiosa. In spongious bone QUS variables show anisotropy reflecting the anisotropy of the trabecular network. Ultrasound propagation depends on the amount and elasticity of the solid bone and the architecture of the trabecular network. Simulation studies indicate that changes in mineralization have a different impact on DXA and QUS. A combined measurement of QUS and DXA at the same site might therefore help to separate the increase of mineralization from an increase in bone mass. Cortical bone . In cortical bone ultrasonic waves (lamb waves) are guided through the cortical plate. Their velocity depends on the direction of the propagation, the thickness of the cortical plate, the cortical porosity and the elasticity of the material. Properties of the collagen and mineral fibres contribute to the elasticity. Especially the mineralization has been identified to have a strong impact on the velocity. Ultrasound propagations along the long bone axis and perpendicular to it have been investigated. In our simulation studies we found that mineralization changes have a stronger impact on ultrasound velocity in both modes than changes in porosity, but also that the modulation of the velocity by these changes differs in both directions. A combination of measurements in both directions might, therefore, be useful to assess changes in porosity and mineralization separately.

15

We will test the following hypotheses: � A combination of site-matched QUS and DXA measurements allow the separate

assessment of variations in bone mass and mineralization [16] A combination of cortical QUS measurements at the tibia in three different directions

allows the separate assessment of variations in cortical thickness, porosity and mineralization

� Incorporation of bone material properties in addition to BMD and bone microstructural properties and BMD will improve the estimation of fracture risk in bisphosphonate-treated patients.

The project is funded by the German Federal Ministry of Education and Research (Biomechanically founded individualised osteoporosis and treatment, BioAsset) In vivo measurement of fracture relevant material p roperties at the human femoral neck with ultrasound Standard radiological measurements of bone density (DXA) are poor predictors of the risk for osteoporotic cervical fractures. Some studies indicate that properties of the cortical shell of the femoral neck like porosity and thickness have an impact on the fragility of this site. Ultrasound guided waves through the femoral neck might be used to obtain knowledge about these fracture relevant properties. We will combine following methods in order to develop an in vivo applicable method for the measurement at the femoral neck cortex: Simulation of the ultrasound propagation using signals of different frequencies generated by coded excitation, an array for the detection of the guided wave pattern and improved methods of signal analysis Testing of the developed methods at phantoms and specimens ex vivo Development of an in vivo applicable device Testing in an in vivo pilot study Funding proposal sent to Deutsche Forschungsgemeinschaft In vivo Assessment of Femoral Neck Strength Using F inite Element Modeling and Simulation Nowadays, human beings are suffering from an accelerating prevalence in hip fracture, largely due to the osteoporosis development at the femoral neck which leads to a substantial decrease in bone strength. Towards a comprehensive evaluation of the strength of the femoral neck, tremendous efforts have been directed to mechanically test the in vitro strength of the femur neck. However, the femur can behave significantly different under the in vitro and in vivo conditions, making the in vitro attempts compromised in offering valued information to assess the in vivo strength of the femoral neck. Allowing for this, this study proposes an attempt to evaluate the in vivo strength of the femoral neck, taking advantages of finite element (FE) analysis, computed tomography (CT) and quantitative ultrasound (QUS). The geometric features of the femur neck can be obtained with the assistant of CT, and incorporated into FE software to construct the FE model. Mechanical test can be carried out after the FE model was assigned with the in vivo material properties of the femur neck. Nevertheless, the in vivo properties of the femoral neck are currently inaccessible. Allowing for this, we propose a substitution method of using the in vivo property of a tibia like its elasticity that can be in vivo achieved, for example using QUS, as a surrogate of that of the femur. These properties could be added to an FE-model, increasing its power for the estimation of fracture risk. Such an attempt to test the in vivo strength of the femoral neck can be a great step towards in vivo assessment of the risk of hip fracture, possessing noticeable significance. Funding proposal sent to Humboldt Foundation In vivo measurement of trabecular bone at the human femur

16

In a pilot study we have demonstrated that QUS measurements at the human femur in vivo are feasible and that QUS can discriminate between women with and without fractures at least as good as DXA. However, the machine used was complicated and difficult to run, which prevented its application in a larger patient study. In the meantime we built an ultrasound array and the electronics for the signal processing and tested it successfully in an ultrasound scanner for the measurement at the calcaneus. We will build a new in vivo applicable machine for measurements at the trabecular trochanter of the human femur using this setup and test it in a larger patient study. The project is funded by the European commission under the programm Interreg IVA: Cross-border collaboration between Germany and Denmark” Development and validation of novel ultrasound base d in-vivo technologies for the noninvasive assessment of bone healing in small ani mal bone healing models (DFG Ra1380/8 submitted, Principal Investigator: Kay Rau m, LEA co-principal investigator: Pascal Laugier) The aim of this project is the development of a quantitative ultrasound (QUS) based, non-invasive, non-ionising tool for in-vivo monitoring and stimulation of early callus formation in a rat osteotomy model. After in-vitro measurements, 3D micro-elastic models of the osteotomy region will be developed. These models will be used for in-silico sound propagation simulations through the osteotomy gap. Acoustic stimulation levels and sequences required for osteogenic determination of mesenchymal stem cells will be determined in-vitro in cell cultures. We hypothesize that in comparison to other imaging modalities, QUS has superior quality for the diagnosis of the early (non-mineralized) phases of callus formation, because sound propagation properties, e.g. speed of sound (SOS) and broadband ultrasound attenuation (BUA) are sensitive to callus soft tissue alterations. While low-intensity QUS with short pulse excitation in the MHz-range can be applied in vivo for the evaluation of soft and mineralized tissues, the same device can also be used for controlled local stimulation by exposure at higher intensities and much longer exposure times. The novelty of this approach is that the use of a focal transducer setup allows an image guided and spot-limited local deposition of acoustic energy and subsequent fluid flow, stress and strain. Specific thresholds for the required energy deposition will be determined by a parametric in-vitro cell culture study. Towards the establishment of the in-vivo method, we will − design and validate an ultrasound based, non-invasive, non-ionising and functional

imaging tool for a rat osteotomy defect model in an in-vitro study, − develop 3D micro-elastic sound propagation models of the repair region, − optimize mechanical stimulation levels with focused ultrasound in-vitro and in-silico. The proposed QUS method can be used as a non-invasive alternative tool for monitoring and mechanical stimulation in small animal bone healing research. Moreover, we anticipate that the technology can then be translated to a transportable device to assess the functional quality of the tissue apposition following a fracture or an osteotomy in human patients. This would provide a decision-guidance for an individualized and temporally synchronized adjustment for follow-up bone healing treatment strategies. Callus tissue formation could be interpreted more accurately and set in context with the time course of their occurrence and the patients overall healing capacity. Thereby such a diagnostic tool would be very valuable to set the indication for additional patient specific treatment at the earliest time point, when a satisfactory healing is not to be expected. Moreover, the refinement of an ultrasound transmission technique to localized stimulation of the endogenous healing process would open new fields and opportunities for the treatment of impaired bone healing situations. The low-cost and bedside application has the potential to prevent healing complications and to reduce the time of hospitalization. Thereby we anticipate remarkable economic and social benefits for the treatment of affected patients.

17

3. OUTCOMES AND EXPECTED RESULTS This work may lead to : − advanced bone measuring US modalities − a unique set of data of multiscale cortical bone properties (stiffness tensor, toughness,

micro- and nano-porosity, characteristics of mineral and collagen phases) − the progression of our fundamental understanding on how various aspects of bone affect

stiffness and toughness − insights into relationships between stiffness (and Poisson’s ratios) and strength − innovative ultrasound-based technologies to enhance skeletal status assessment and

improve fracture risk prediction. Finally, such studies may ultimately impact the medical field by directly revealing (i) how these aspects are reflected by ultrasound guided propagation and (ii) by the establishment of ultrasound measurement strategies to assess specific bone characteristics to early detect patient at risk or monitor therapies. More specifically, understanding how micro- and nano-scale features are related to mechanical properties and knowing the link between stiffness and toughness may help to better establish QUS modalities as a diagnostic tool for bone diseases. 4. Opportunities and attractiveness The three bone research groups involved in this research proposal are world class groups who has been involved for more than 20 years in sustained research in the field of bone quantitative ultrasound. Research centres on understanding the constitutive behaviour of bone, using experiments, numerical simulations and analytical models, on developing innovative ultrasound-based methods and technologies for in vivo bone assessment and on multi-center clinical evaluation of new technologies. It is responsible for taking this domain of study that virtually did not exist 20 years ago, to a level that now encompasses all aspects of the research, including instrumentation, theoretical models and numerical tools for simulation, basic experimentation and clinical studies. As the research matured, it became clear that there was a large class of ultrasound technologies that could be developed to assess cortical or cancellous bone, various skeletal sites, or provide different bone properties. Much of the ground-breaking works and technological breakthrough in bone quantitative ultrasound, including ultrasound bone imaging, use of guided waves for cortical bone assessment, acoustic microscopy and nonlinear acoustics applied to bone recently have been done by the LEA partners. As an indication of the ULAB LEA stature in the domain of study, researchers of ULAB organized several international conferences in the field: ASBMR Working Group on Quantitative Ultrasound Techniques in Osteoporosis; International Bone Densitometry Workshop (Annecy, France, 2004); European Symposia on Ultrasonic Characterization of Bone (Paris, France, 2005 - Halle, Germany 2007 - Bydgoszcz, Poland, 2009 – Jyväskylä, Finland, 2011). They have been invited to write editorials or articles for peer reviewed journals of the field and to lecture at many major International meetings. They have edited a book on Bone Quantitative Ultrasound (Bone QUS, Springer, 2011) and a special issue for the Journal IEEE UFFC. As a natural European leader, ULAB has sought to network research in the field at the European level.

ULAB now holds a leading international position in the field of application of quantitative bone ultrasound to assess skeletal health and to improve fracture risk assessment for osteoporosis by coordinating and combining interdisciplinary basic research with

18

development of novel instrumentation and clinical evaluation of multisite, multiscale, & multiparametric US-based technologies. Besides the share of research facilities, technologies, samples and data, major efforts of the ULAB are to provide efficient training from the undergraduate to the PostDoc levels and to initiate international research collaborations of young researchers by research exchanges, and co-supervision of graduate students. This comprises joint international projects, student and PostDoc exchange, joint doctoral programs with European collaborators, and the initiation of the biannual conference series “European Symposium on Ultrasonic Characterization of Bone (ESUCB)”.

19

ANNEX

MEMBERS OF THE LEA AT THE DATE OF JANUARY 1, 2012

A.4.1 - Members of Laboratoire d’Imagerie Paramétrique, UMR 7623 (CNRS, Université Paris 6) Name: Pascal Laugier Title: Dr., DR CNRS Time spent on the LEA project: 25% Name: Amena Saied Title: Dr., CR CNRS Time spent on the LEA project: 25% Name: Quentin Grimal Title: Dr., MCF UPMC Time spent on the LEA project: 50% Name: Maryline Talmant Title: Dr., CR CNRS Time spent on the LEA project: 20% Name: Jean-Gabriel Minonzio Title: Dr., CR CNRS Time spent on the LEA project: 30% Name: Mathilde Mouchet Title: PhD student Time spent on the LEA project: 100% Name: Pierre NAULLEAU Title: PhD student Time spent on the LEA project: 100% Name: Simon BERNARD Title: PhD student Time spent on the LEA project: 100% Name: Ludovic Hamon Title: post-doc student Time spent on the LEA project: 100% A.4.2 - Members of former Labor für quantitative B- Bild-Sonographie und akustische Mikroskopie (Universitätsklinikum Halle) NOW: Q-BAM LABORATORY AT JULIUS WOLFF INSTITUT & BERLIN BRANDENBURG SCHOOL FOR REGE NERATIVE MEDICINE AT CHARITÉ-UNIVERSITÄTSMEDIZIN BERLIN Name: Kay Raum Title: Univ.-Prof. Dr.rer.nat. Time spent on the LEA project: 10 %

20

Name: Peter Varga Title: PhD Time spent on the LEA project: 20 % Name: Jan Laufer Title: PhD Time spent on the LEA project: 20 % Name: Ferenc Lajos Molnar Title: Dipl.-Phys. Time spent on the LEA project: 100 % Name: Bernhard Hesse Title: Dipl.-Phys. Time spent on the LEA project: 50 % Name: Daniel Rohrbach Title: Dipl.-Bioinf. Time spent on the LEA project: 50 % Name: Katrein Sauer Title: B.Sc. Time spent on the LEA project: 30 % Name: Nahid Haky Title: Technical Assistant Time spent on the LEA project: 30 % Name: Bernd Preininger Title: Dr. med. Time spent on the LEA project: 20 % A.4.3 - Members of Section Biomedical Imaging at Un iversitätsklinikum Schleswig-Holstein (UKSH), Kiel, Germany Name: Claus Glüer Title: Professor Time spent on the LEA project: 5% Name: Reinhard Barkmann Title: Dr. Time spent on the LEA project: 50% Name: Kerstin Rohde Title: PhD-student Time spent on the LEA project: 100% Name: Melanie Daugschies Title: PhD-student Time spent on the LEA project: 100% Jiangang Chen, PostDoc Title: Psot-doc Time spent on the LEA project: (if funding proposal successful) 100%

21

ANNEXE 5

PROJECTED BUDGET FOR 2012

Pays Resources Amount (€)

Human resources (ETP*)

FRANCE A) CNRS a) Additional resources from CNRS,

European Affair Relations 25 000

b) laboratory budget 10000 c) Human resources 5.0 Sub-total for CNRS 35000 5.0 B) UNIVERSITE PARIS 6 a) laboratory budget 0 b) Human resources 0.5 Sub-total for University Paris 6 0 0.5 ALLEMAGNE A) CHARITÉ-UNIVERSITÄTSMEDIZIN BERLIN

a) laboratory budget 17 500 b) Human resources 3.3 Sub-total for Universitätsklinikum Halle 17 500 3.3 B) UNIVERSITÄTSKLINIKUM SCHLESWIG-HOLSTEIN

a) laboratory budget 10 000 b) Human resources 2.55 Sub-total for Universitätsklinikum

Schleswig-Holstein 10 000 2.55

TOTAL 62 500 11.35 * ETP : Equivalent Temps Plein (Full time)