Azalée is a French company, founded in 2012, which develops an innovative technology for assessing the characteristics of the cortical bone

The VOG* (Vitesse des Ondes Guidées) technology is based on the measurement of ultrasonic guided modes in the cortical part of the bone that behaves as a waveguide.

It allows non-invasive measurement of cortical thickness and porosity in the arm (radius) and leg (tibia).
Azalée is the result of the work of the Biomedical Imaging Laboratory (INSERM CNRS/Université Pierre et Marie Curie) which conducts fundamental and applied research on morphological, functional and molecular biomedical imaging methods on small animals and humans.

Azalée is a subsidiary of Quattrocento, a company builder specialising in life sciences equipment.

*VOG technology is protected by 3 patent families

An innovative method for assessing the characteristics of cortical bone


Non invasive





The VOG technology is the result of research by Professor Pascal Laugier, Jean-Gabriel Minonzio, Emmanuel Bossy and Maryline Talmant, specialists in ultrasound for bone. The measurement takes place in 3 steps.

A dedicated, multi-transmitter probe is used to generate ultrasonic waves in the cortical bone at the radius and tibia region.
Probe receivers retrieve modes guided by the cortical part of the bone.

A processing algorithm (based on singular values decomposition) has been developed to analyze the 5*24 acquisitions (5 transmitters, 24 receivers) to obtain the complete spectral image of the cortical bone.

The experimental data are then compared with a database of models. The one with the strongest correlation to measurement provides mechanical bio-markers of the bone, including cortical thickness and porosity.

The bone model developed in the laboratory has already made it possible to measure 2 relevant parameters of cortical bone, while the spectral image opens up new perspectives for analysis





In vivo measurement at radius

Q. Vallet, N. Bochud, C. Chappard, P.
Laugier, and J.-G. Minonzio, «In-vivo cortical bone characterization using guided waves measured by axial transmission,» IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 63 1361 – 1371 (2016).

Reverse problem, genetic algorithms

N. Bochud, Q. Vallet, T. Bala, H. Follet, J.-G. Minonzio, and P. Laugier, “Genetic algorithms- based inversion of multimode guided waves for cortical bone characterization», Phys. Med. Biol. 61, 6953 – 6974 (2016).

Correction for attenuation

J.-G. Minonzio, J. Foiret, M. Talmant, P. Laugier, “Impact of attenuation on guided mode wavenumber measurement in axial transmission on bone mimicking plates,” J. Acoust. Soc. Am. 130, 3574-3582 (2011).

Mode measurement using SVD-based method

J.-G. Minonzio, M. Talmant, and P. Laugier, “Guided wave phase velocity measurement using multi-emitter and multi-receiver arrays in the axial transmission configuration,” J. Acoust. Soc. Am. 127, 2913-2919 (2010).

Ex vivo measurement

J. Foiret, J.-G. Minonzio, Ch. Chappard , M. Talmant, and P. Laugier, “Combined estimation of thickness and velocities using ultrasound guided waves : a feasibility study on in vitro cortical bone samples,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 61, 1478-1488 (2014).

Two-layer model

N. Bochud, Q. Vallet, J.-G. Minonzio, and
P. Laugier, «Predicting bone strength with ultrasonic guided waves» Scientific Reports 7, 43628 (2017).

Bi-directionnal correction

L. Moreau , J.-G. Minonzio, J. Foiret , E. Bossy , M. Talmant, and P. Laugier, « Accurate measurement of guided modes in a plate using a bidirectional approach, » J. Acoust. Soc. Am. 135, EL15-EL21 (2014).

Correction for thickness variation

L. Moreau, J.-G. Minonzio, M. Talmant, and P. Laugier, « Measuring the wavenumber of guided modes in a thickness-varying waveguide, » J. Acoust. Soc. Am. 135, 2614 – 2625 (2014).


Pr Pascal Laugier
CNRS Research Director, LIB Director

Jean-Gabriel Minonzio
CNRS Researcher, LIB

Emmanuel Bossy
Professor, LIPHY, Grenoble University

Maryline Talmant
CNRS Researcher, LIB


VOG technology is particularly well suited for clinical studies in osteoporosis.
A pilot trial, currently being published and aimed at predicting fracture risk, was conducted on 299 postmenopausal patients in the rheumatology department of Cochin Hospital.

VOG technology, which is non-irradiating and non-invasive, is the ideal tool for monitoring bones in children, and a pilot trial is ongoing with the Paediatrics Department of the Trousseau Hospital for the follow-up of myopathic children.

VOG technology is particularly suitable for monitoring the effects of cortical bone altering therapies such as long term corticosteroids or hormone therapies.

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