Submitting InstitutionUniversity of Cambridge
Unit of AssessmentGeneral Engineering
Summary Impact TypeTechnological
Research Subject Area(s)
Information and Computing Sciences: Artificial Intelligence and Image Processing, Information Systems
Summary of the impact
Research at the University of Cambridge Department of Engineering (DoEng)
has enabled accurate positioning to be added to 2D freehand ultrasound
probes to enable the acquisition of large coherent blocks of
high-resolution 3D ultrasound image data. The software code base developed
in the DoEng was licensed to two separate companies, Schallware and
MedaPhor, to enable them each to develop an ultrasound training product.
Both companies have sold to more than 30 customers worldwide during the
REF impact period; the Cambridge software had a key role in contributing
to the innovation and quality of the products developed by both companies,
and significantly increased the speed at which they were able to bring
these products to market.
The underpinning research on 3D ultrasound imaging is founded on the work
of the Medical Imaging Group ("the Group") and its three principal members
in the University of Cambridge Department of Engineering (DoEng).
Professor Richard Prager founded the Medical Imaging Group when he became
a Lecturer in the DoEng in 1992 (promoted to Professor in 2008). He
started the preliminary research on 3D ultrasound imaging as Principal
Investigator for the EPSRC-funded project "Stradivarius", which
started in October 1992 and finished in February 1996 (all significant
research was conducted from 1993 onwards). Dr Andrew Gee joined the Group
as a DoEng Lecturer in 1996 to help lead the EC-funded project, "Solus-3D"
(Standardisation of On-Line Ultrasound Scanning in 3 Dimensions), which
ran from 1996 to 1999 with Prager as the Co-Investigator. Graham Treece
was a Research Student in the Group before working as a Research Associate
from 2001 on the Group's EPSRC-funded project "High Definition 3D
Ultrasound Imaging", which ran from 2000 to 2004 with Prager as the
Principal Investigator. Treece was subsequently awarded a prestigious
five-year Fellowship by the EPSRC / Royal Academy of Engineering before
becoming the first holder of the Evelyn Trust Lectureship in Engineering
for Clinical Practice in 2008. These members of the Group, the grants
mentioned above and Treece's fellowship created the research outputs
Tracked 3D ultrasound involves using a magnetic or optical tracking
device to measure the trajectory of the ultrasound probe while the
clinician is scanning. This information can then be combined with the
ultrasound images to produce a three-dimensional data set. It is
particularly useful where an extended volume needs to be scanned, or in
cases when there is a need to register the acquired data to an external
coordinate system. The Group began work on the Stradx tracked 3D
ultrasound software in 1996. In 2004, the Group created a second system
called Stradwin, offering similar functionality but with a user
interface designed for clinicians. Clinical applications were provided
through collaboration with the University Department of Radiology at
The first achievement of the research was to reduce the time for accurate
spatial calibration of the acquisition system from half a day to about ten
minutes [1,2]. Novel tools were then produced for visualisation  and
volume measurement  of the unstructured data. The Group invented a new
"voxel-free" approach to represent data of this sort that resulted in
clearer images, more accurate measurements and faster performance . A
unique algorithm was created to help mitigate the distortion of acquired
data due to the flexibility of human tissue , and the overall accuracy
of the system was subjected to detailed assessment .
The result is a comprehensive system for the acquisition, visualisation
and measurement of accurate three-dimensional ultrasound data. Because of
the fixed coordinates of the tracking system used to measure the
trajectory of the probe, this data can be easily assembled into a large,
co-registered, anatomical library.
References to the research
1.* R. W. Prager, R. N. Rohling, A. H. Gee and L. Berman. Rapid
calibration for 3-D freehand ultrasound. Ultrasound in Medicine and
Biology, 24(6):855-869, DOI: 10.1016/S0301-5629(98)00044-1, 1998.
2. P-W. Hsu, G. M. Treece, R. W. Prager, N. E. Houghton, and A. H. Gee.
Comparison of freehand 3-D ultrasound calibration techniques using a
stylus. Ultrasound in Medicine and Biology, 34(10):1610-1621, DOI:
10.1016/j.ultrasmedbio.2008.02.015, October 2008
3.* R. W. Prager, A. H. Gee and L. Berman. Stradx: real-time acquisition
and visualization of freehand three-dimensional ultrasound. Medical Image
Analysis, 3(2):129-140, DOI: 10.1016/S1361-8415(99)80003-6, 1999.
4. G. M. Treece, R. W. Prager, A. H. Gee and L. Berman. 3D ultrasound
measurement of large organ volume. Medical Image Analysis, 5(1):41-54,
DOI: 10.1016/S1361-8415(00)00034-7, 2001.
5. G. M. Treece, R. W. Prager, A. H. Gee and L. Berman. Correction of
probe pressure artefacts in freehand 3D ultrasound. Medical Image
Analysis, 6(3):199-214, DOI: 10.1016/S1361-8415(02)00080-4, 2002.
6.* G. M. Treece, A. H. Gee, R. W. Prager, C. J. C. Cash and L. Berman.
High definition freehand 3-D ultrasound. Ultrasound in Medicine and
Biology, 29(4):529-546, DOI: 10.1016/S0301-5629(02)00735-4, 2003.
*References which best represent the quality of the underpinning research.
Details of the impact
Based on the research described above, Schallware GmbH developed an
ultrasound simulator that allows clinicians to practice diagnostic
scanning under realistic conditions using a library of normal and
pathological cases. A dummy probe is moved over a dummy torso to generate
the relevant ultrasound images on the simulator screen, just as would be
shown on an ultrasound machine screen for a real scan.
In May 2007, Schallware bought a one-off source-code licence for the
DoEng Stradx software, which was arranged through Cambridge Enterprise, to
provide a starting point for the development of their product. Stradx
provides tools for acquisition, visualisation and measurement of tracked
3D ultrasound, and all of these are important components in the Schallware
system. The Schallware General Manager says: "The benefit of Stradx
source was the access to a huge collections of ideas", and for the
development of the Schallware product he says: "our [i.e. the
Schallware] software development started with Stradx source for
acquisition and simulation application". He continues: "With
Stradx source we maybe avoided wrong development paths and could
establish in short time a first prototype. About that I am still lucky
Since the start of 2008, Schallware has built up 30 customers in 10
countries including Johns Hopkins University; NAIT, Edmonton, Canada;
Zurich University; Erlangen University; and GMC Dubai, UAE. It also has a
leasing business with five simulators being used to run about 25 courses
annually in universities in Germany, Switzerland, the Netherlands and
Belgium. Attendees at these courses include clinicians and staff from
pharmaceutical companies such as Merck, Sharp, Novatis and Dohme. The
Schallware General Manager, estimates that 2,400 clinicians have been
trained in these courses alone (i.e. not counting the 30 customers with
their own Schallware system). Revenue from Schallware's 3D ultrasound
simulators was EUR250k in 2011 and EUR300k in 2012.
MedaPhor Limited is a supplier of simulator software that integrates with
a variety of ultrasound systems to enable sonographer training without the
need for a human subject. The training system needs large and
comprehensive datasets to provide the breadth of scans that a trainee
sonographer needs to practise.
In January 2011, MedaPhor bought a one-off licence through Cambridge
Enterprise for the DoEng Stradwin ultrasound acquisition system and
software code-base to help it build an accurate three- dimensional
ultrasound atlas for their clinical training system, ScanTrainer. Stradwin
allows for the rapid acquisition and integration of these datasets into
the MedaPhor software. The time taken to produce a single dataset and make
it ready for training use is now approximately two weeks as a result of
having the volume of high-resolution data and necessary positional
information. Before the purchase of Stradwin, the production of such a
dataset took in the region of three months.
MedaPhor has specifically stated that spatial calibration, such as that
described in reference , was key to achieving the required accuracy. As
a consequence this was fundamental to their ability to acquire accurate
data from multiple patients.
The real-time acquisition and visualisation tools described in reference
 increased the efficiency of their workflow by enabling the quality and
appropriateness of 3D data to be checked immediately after recording.
MedaPhor also use Stradwin for data alignment  and volume measurement
 because Stradwin's algorithms have been designed specifically to
address the challenges presented by the structure of 3D ultrasound data.
They therefore out-perform other more generic tools.
The Stradwin software has proved to be a flexible platform with a sound
architecture that MedaPhor now use as a basis for much of their work.
MedaPhor's Chief Technical Officer  says that the purchase of Stradwin
was a key positive step in the development of the company and they could
not have achieved their current success without it. MedaPhor's customers
include Birmingham Women's Hospital, St James's University Hospital Leeds,
Yale University, the Karolinska Institute (Stockholm) and the Fremantle
Institute (Western Australia).
As at April 2013, MedaPhor had sold over 50 units in 9 countries.
MedaPhor estimate that, in the UK alone, more than 500 people to date
(June 2013) have trained using ScanTrainer during the REF impact period.
Revenue from its 3D ultrasound simulators was GBP362k in 2011 and GBP739k
The systems provided by both Schallware and MedaPhor enable trainee
clinicians to perform clinical ultrasound scans relating to a wide variety
of different examination protocols and different pathologies. The trainees
gain a breadth of experience together with a quality of objective feedback
that would not be possible without these training systems. A Professor at
Rigshospitalet, Copenhagen University Hospital, said of the MedaPhor
system: "We are certain that the ScanTrainer will be a great tool for
acquiring some of the necessary skills before examining the patients."
Binary versions of the DoEng software are also available for
free-download on the web: Stradx since 1997 and Stradwin since 2004. Both
systems are used by a wide variety of academic and commercial research and
development organisations. In the last five years, the use of Stradwin as
a research tool has been mentioned in 51 publications with no co-authors
from the Cambridge group. For instance, a lecturer at the University of
Queensland used Stradwin as a tool in his work and stated: "We
routinely use Stradwin in our research laboratory as a tool for
measuring structural properties of muscle and tendon in applied clinical
research. Stradwin is not only a stable platform for undertaking
freehand 3D ultrasound measurements, but it provides us with all of the
advanced analysis tools we require, including volume reconstruction and
quantifb01cation, 3D length measurements, re-slicing to examine multiple
planes and more recently 3D elastography. For example, in 2009, we used
it to compare medial gastrocnemius muscle volume, physiological
cross-sectional area (PCSA), muscle length, fascicle length, and
pennation angle in children aged 2 to 5 years with spastic cerebral
palsy (CP) and in typically developing children...3D ultrasound and the
Stradwin software allowed us to make scans to children's muscles in
seconds and therefore meant that children did not have to be sedated, as
would have been the case for other imaging modalities such as magnetic
resonance imaging (MRI). The work showed the need for early intervention
in order to minimize loss of muscle PCSA in spastic CP. This insight has
provided valuable feedback to staff treating children at the Hugh
Williamson Gait Analysis Laboratory, the Royal Children's Hospital,
Melbourne. This work also resulted in a high-quality publication in
Developmental Medicine & Child Neurology in 2011 and makes this data
available to hospitals around the world. A further study (2009) has
showed the effects of Botulinum Toxin (Botox) injections on muscle
development in these young children with CP...and has prompted a new
randomised controlled trial at Royal Children's Hospital in Brisbane to
determine whether Botox injections may have a deleterious effect on
muscle development. We have 4 similar examples from our work since 2008
that have resulted in publications in high-quality journals. The
provision of this software has had a signifb01cant effect on the speed
and quality of our efforts and their translation to clinical practice.
Many other collaborators in our fb01eld, both academic and clinical, now
also use Stradwin as the standard foundation for their work." 
Sources to corroborate the impact
- Statement received from General Manager, Schallware GmbH
- Chief Technical Officer, MedaPhor
- Professor at Rigshospitalet, Copenhagen University Hospital,
- Statement received from Lecturer in Exercise and Sports Science,
University of Queensland