Magnetic Resonance Image Texture
BRUSSELS WORKING GROUP - 25th
- 28th June, 1998
A Review of
Texture Methods and Applications in MRI
R E P O R T
Download MS-Word document: rbl3221.doc
|Dr R A Lerski, Dundee
||Dr Y Rolland, Rennes
|Prof Dr L R Schad, Heidelberg
||Dr M Bock, Heidelberg
|Prof Dr A Materka, Lódz
||Dr M Strzelecki, Lódz
|Mr P Szczypinski, Lódz
||Prof A Spisni, Parma
|Prof Dr R Dommisse, Antwerp
||Dr P Ring, Copenhagen
|Dr O Yu, Strasbourg
||Ms S Allein, Brussels
|Dr H Stødkilde-Jørgensen,
||Ass Prof A Santos, Madrid
|Mr N Malpica, Madrid
||Prof R Muller, Mons
|Mr A Amorison, Mons
||Mr H Langenberger, Vienna
|Ass Prof A Lundervold,
||Mrs A Barclay, Dundee
Thursday 25th June,
commenced with R Lerski (Chairman, Cost B11) welcoming everyone to Brussels
for the first Working Group meeting of COST Action B11, for which there
is funding for the next four years (started March 1998).
was given by R Lerski to explain the methods by which the COST programme
functions, along with some of the bureaucracy involved. In particular,
reimbursement to delegates appears to take around 3 months, but Dr Lerski
will write to see if this can be "speeded up".
R Lerski has applied
for a subsidy to set up a Web-page describing the Action, but so far, this
has been blocked by the Commission. It is hoped that this is temporary.
2) Presentation by
Dr Y Rolland - The Clinical Value of Texture Analysis
Y Rolland started
by stating that the questions to be answered were:
"The problems yesterday - can we perform texture analysis"?
"The problems today - how to perform texture analysis"?
He commented that
it was technically easy to carry out texture analysis but often the exact
purpose of the experiment is not clear. It is easy to demonstrate results,
but not so easy to compare the clinical value. He also proposed that texture
analysis could be added to information already available to Radiologists
in order to find a better diagnosis.
R Muller asked in what specific
cases it may be helpful. Would it be help for the image discrimination
and help for the diagnosis, as they are two different things? In some pathologies
there is no real requirement for texture.
Y Rolland stated that it was
difficult to know how to use it:
a) Do it manually, e.g.,
as a radiologist with visual interpretation?
b) Do it with computer,
i.e., as we propose with NMRWin.
He recommended writing exactly
what one is reporting - try to standardise.
L Schad - aim from beginning
- is it better to have tissue characterisation now we have texture? He
said that he hoped it would be possible to differentiate between normal
and abnormal tissue, but asked the questions:
a) How we can normalise?
b) How we can standardise?
commented that it would probably be necessary to try to combine texture
analysis with other information.
R Lerski stated that, in his
experience of texture analysis in MRI, it was usual to experience different
results on the same machine and also on different machines. He also mentioned
that, so far, the technique and protocol have not been sufficiently developed
and that some means of standardisation or processing would be necessary.
M Bock thought it necessary
to have specific information as to exactly what we would be looking for
in pathological terms so that we can predict which parameter would be good,
and which ones would not be.
by R Lerski - Texture Analysis in Ultrasound and X-ray
A review was given of the
results achieved by texture analysis in X-ray and in ultrasound. These
date back to 1976.
R Muller asked - "What was
the end image". If the liver was cirrhotic or normal - can you see any
difference on CT? Y Rolland replied that there were not many differences.
Y Rolland also stated that
it wasn?t clear in the case of ultrasound what the pixel meant as the resolution
is too poor, therefore it is not obvious what you are looking at or measuring.
4) Presentation by Prof
Dr L R Schad - Texture analysis in MRI and status of NMRWin
L Schad gave a full review
of the usefulness of texture analysis in MRI and commented that he would
want to find out where the limits are and what are the best parameters.
A Lundervold queried whether
the results of all echoes or only a single echo were used.
L Schad replied that 4 images
were usually used:
T1 parameter image mono
T2 parameter image mono
T1 dependent image
T2 dependent image
Most radiologists use all
or some of these images for diagnosis
Friday 26th June, 1998
1) Presentation by Dr R
A Lerski - Results and Methods
An introduction was given
of this session, viz., the methods of texture analysis, multiparameter
evaluation and test object results from the Biomed Concerted Action.
2) Presentation by Prof
Dr A Materka - Texture Analysis Methods
A full report was distributed
summarising an initial summary of the literature in texture analysis. A
detailed and excellent review was given of the various methods available
and an example of an application in skin pathology was presented.
Y Rolland asked about the
work done on skin pathology - is it worth doing it? A Materka?s reply was
that, yes, his clinical collaborators think so, and that is the important
Y Rolland commented that a
method for identifying discriminating parameters can always be found.
3) Presentation by Ass
Prof A Santos - Multiparameter evaluation methods
A detailed review was given
of the various methods available to evaluate the texture parameter results,
e.g., discriminant analysis, principal component analysis (PCA), neural
A Materka asked if PCA can
be used for image classification. The reply was that it is useful if there
are a lot of variables and also a useful tool for research.
4) Presentation by Dr
R A Lerski - Test Object Construction and Results
R Lerski explained the construction
of the Test Objects, and subsequent results, from the previous BIOMED Concerted
R Lerski continued by asking
the following questions:
a) Why is the study on
individual machines so different?
b) What is it that changes
c) Is it signal-to-noise?
d) Is it different field
M Bock asked about the difference
between Siemens and Philips machines. S Allein commented that she thought
the different fields strengths were a very important factor due to possible
susceptibility difficulties with the test objects.
A Lundervold wondered if
it may be the calibration of the reconstruction algorithms.
R Lerski thought it may be
the same argument as with T1 and T2. That is, it is important to very carefully
determine how to carry out the measurements well before deciding on their
A Lundervold suggested that
it may not be possible to measure at different centres, but it would nevertheless
be good to get the same separation of textures on different machines.
asked whether the measurements had been completed on the same scanners,
to which R Lerski replied that they were, however, the variation wasn?t
as much. The same test tubes were also sent round the various centres.
R Lerski suggested it may
be a good idea to scan the tubes very extensively for 3/4 days on one machine
and then spend time analysing the data.
L Schad commented that he
wasn?t really sure if the same parameters were used in the image reconstruction
by all manufacturers or in all machines, and suggested it may be better
to do the reconstruction using Fourier transform ourselves to determine
that the settings were actually the same.
R Lerski stated that maybe
we should have distributed the actual sequence to all centres.
Y Rolland wondered why MR
was used instead of CT, which has less parameters and may be simpler to
understand. L Schad replied that MR had a better soft tissue contrast.
Nevertheless, Y Rolland suggested trying CT with foam only.
A Lundervold thought maybe
another sequence would be more relevant, e.g. diffusion. Wouldn?t the biological
tissue be more obviously different? He asked if variability mattered -
many other parameters that can be used. R Lerski stated that trabecular
bone had been used for same experiments but didn?t get very good separation.
L Schad suggested that if
we changed to other parameters (e.g. diffusion, perfusion) he doesn?t think
different lesions would be separated. We would have to first find out which
machine parameters influence our outcome.
A Santos asked if particular
texture parameters are machine dependent. R Lerski thought we should look
at this as there is enough existing data to carry this out, and it would
give a better indication of problems before carrying out a new trial.
A Santos has access to a 4.7
Tesla machine and R Lerski to a 7 Tesla system.
R Lerski - Assuming that texture
is same as tube is moved across - maybe more than 6 ROIs should be taken,
and that maybe something better than foam tubes could be used.
R Lerski commented that trabecular
bone is not easy to get in lower age groups and that it is a problem to
remove the tissue out of the bone. Also, the texture is not the same over
the whole area of bone.
L Schad suggested the possibility
of sending someone round each centre involved to measure the test objects
or tubes, and asked if it could be done as a short term mission. This would
also ensure that all parameters would definitely be the same.
1) Clinical Problem
Technical point of view -
organ with not much image artefacts is required.
White matter diseases, i.e.
MS, but the problem is that the spinal cord is not studied
Brain Lesions (tumour oedema)
1) Markov - Texture
2) Re-analysis of foams
and estimate SNR in gel
Have been measured already:
Different Slice Width
- Short term mission from
Lódz to Heidelberg.
- To consider further
- New features e.g., ROI
- Store ROI data
Groups with access
to MATLAB: Lódz
Groups with access
to IDL: Copenhagen
Need a full specification
for ROI pixel storage.
or UNIX) }
Data on Excel
(macro) - R Lerski to send to read log files.
- Trabecular bone
images for downloading - R Lerski to send out.
Foams - composite object,
sepharose, HPLC - 300 microm
? - Perkin Elmer, gels - polysaccharide, fibres, membrane
The present situation
is as shown:
could be attempted
Could try a sum
of parameters from brain and foam tubes to normalise.
Literature (time for mission)
Texture model (big task)
Internal exchange of partners
White matter brain
Dynamic effects (texture
in time domain and spatial domain)
Same ROI in a series of
Breast MRI - contrast
Saturday 28th June,
1) Functional MRI
Existing data - texture analysis
2) Library search - Lódz
Aarhus, Bergen, Strasbourg and Mons
3) Markov - Lódz
4) Variation of texture in reticulated foams
with FOV, NSA - Dundee would perform a full analysis
5) New Data on reticulated foam - SNR constant
- Heidelberg (foams from Copenhagen)
Lódz --> Heidelberg (short term mission)
2) Data Collection
Foam Images (from Dundee)
--> Lódz - Markov modelling
FTP of existing files - make available from Dundee
3) New Measurements
FOV, RES, NSA, Slice width
Foam tubes (4)
SNR Constant --> Heidelberg
NMRWin stores ROI - Lódz --> Heidelberg
Dundee will talk to London about texture routines in MATLAB
Madrid, Bergen and Lódz
DICOM reading - Madrid will investigate
Unscrambler - details to all (from Dundee)
Macro from NMRWin to Excel (from Dundee)
Madrid to look at:
6) Foam --> X-ray CT and Miscellaneous
Parameters from foam (Dundee will send)
Rennes will scan the reticulated foams by x-ray CT
7) Test Objects
Brussels} Wrist machine to investigate
Literature clinical ?hot topics? - Rennes
Antwerp will think about alternatives
T1 100 at 1.5 Tesla
Sepharose - HPLC
Parma will investigate
Gauze ? - Dundee
Embolisation beads - Rennes
Foam - T1, T2 to be changed - Dundee
T2 700 "
8) Slice Thickness
Does it vary between machines or with sequence protocol?
Plots of the variation of texture parameters with slice width
Heidelberg will make the measurements, Dundee the analysis.
9) Multicentre Trial
It might be possible to look at the same ?Siemens? sequence
This centre is involved in a study of the contribution of texture
analysis in the evaluation of cryptogenic temporal lobe epilepsy. Texture
analysis is being applied to standard brain MR imaging of epilepsy patients
with studies of the regions of the ipsolateral and controlateral hippocampus
and the region of amydata. Texture analysis should be used for the detection
of mesial temporary slcerosis and for the assessment of apparently normal
DATE AND VENUE OF NEXT MEETING
Bruker 3 Tesla
Resolution 100 m m
Thursday 19th --> Saturday 21st/Sunday 22nd November, Strathclyde
Graduate Business School, Glasgow, Scotland. Full details to be circulated
COST B11 Homepage