
Show HN: A software solution to ultrasound blood flow monitoring - rscho
http://bigwww.epfl.ch/algorithms/blood-flow-monitoring/#outline
======
rscho
For those interested, this is destined to any situation where monitoring blood
flow is useful, in any vessel available to ultrasound imaging. HN offered me a
repost of this story due to my comments at
[https://news.ycombinator.com/item?id=13423421](https://news.ycombinator.com/item?id=13423421)
, where automated anesthesia has been mentioned. The problem is that making
people sleep is only part of the job, and the feedback required to create an
automated feedback loop is lacking in many aspects of the process. This was
created as a potential piece of the puzzle. Unfortunately, it was deemed too
technical by my boss to be worthy of support (the concept is high-school
physics level, notice...). I am looking for companies/research
groups/individuals active in ultrasound research who would be interested in
attempting to refine the technique, so if you know someone, don't hesitate to
contact me: raoul.schorer@gmail.com

------
fest
I am missing something: doesn't a typical duplex ultrasonography machine
already output blood flow rate?

I recently had such a test and I vaguely recall seeing flow rate in the UI of
machine. Oh, maybe the machine measures blood velocity, and you calculate flow
rate in units of volume/time?

~~~
rscho
The scale present on color flow ultrasonography exams does indicate the
instantaneous speed at all locations on the plane defined by a cross-cut of
the vessel. Duplex ultrasound outputs a time->velocity signal, but only
focused on a single point. The traditional technique to estimate flow uses
duplex, but is imprecise (~30% flow volume error, at best) and hindered by a
lot of manual manipulations making it not reproducible along time and machine
users.

Both techniques have disadvantages, making it difficult to obtain a good flow
estimate. In the clinics, color flow Doppler is used as a mere location and
speed rough indicator. I tried to solve this by including the vessel shape in
a mathematical model, which makes the automated method surprisingly practical
and efficient on those preliminary tests.

------
jonbaer
Can something like this be used to detect (and prevent) DVT?

~~~
rscho
DVT detection by ultrasound (when there is already a DVT installed) is already
pretty efficient, because you don't need to know flow volume for that. We test
it by the compression test, where a blood clot will prevent squashing of the
vein when pressure is exerted on it with the ultrasound probe. Furthermore,
the shape of veins is usually far from circular, making our method less than
optimal.

Our method is geared towards vessels which have enough pressure in them to
constrain them to a circular shape, namely arteries, but also (most likely)
great veins. So it could actually prove useful not in DVT, but to detect one
of its deadly complications: pulmonary embolus. Apart from this, knowing the
flow passing through the pulmonary arteries would prove extremely useful in
many cases. It would have to be tested, though. I cannot be sure that it works
in this particular case.

~~~
jonbaer
Speaking as someone who had DVT/PE there was this stage before experiencing
the PE (to the lungs) in which the calf muscle was red/swollen/cramp - it's
this period of time in which case I felt like (and still feel like) a device
of some type (either low cost ultrasound w/ software) could determine if a
blood thinner or something else is needed - and probably save your life. It's
evident that between sitting long periods (either at your desk programming or
after long flights) that checking the flow is what needs to be done to prevent
DVT/PE in the first place (minus other factors of course). I applaud this work
because it does sound like a great effort towards something like that.

~~~
knz
Did they do a D-Dimer test
([https://en.wikipedia.org/wiki/D-dimer](https://en.wikipedia.org/wiki/D-dimer))?
My understanding is that this can be more reliable than ultrasound (subject to
misinterpretation). I'm sure a doctor would tell you to do both if a PE/DVT is
suspected.

I hope you have recovered well. My wife nearly died from medical negligence
related to a DVT/PE - it can be life changing if it becomes a PE.

~~~
jonbaer
Recovery is a weird word. The anxiety you face after you have one can be
nearly as crippling as what you went through in the first place (this can
probably be said for anything high trauma though). What I can say is that you
learn a lot about blood in general after you have had one and things like
Vitamin K, green food, etc. It did take 2 ultrasounds on the leg to get an OK
to come off thinners, but I still feel there is a window of unknown which
healthy and unhealthy people go through in the clotting of blood that is
severely under treated and was a great case of where knowledge would have
saved a trip to the hospital. I don't in anyway say do-it-yourself-at-home
kits with ultrasound and machine learning algorithms should replace medical
advice but more and more people are dying from blood clots (whether it be food
related, environment, clothes(?)) that it warrants a better look - and I am up
for anything non medicinal - especially ones which can cause excessive
bleeding like current thinners. If I had a friend who had swollen calf muscles
and pain and told them to try something at an urgent care facility to
determine a clot was present and it was low cost for all parties involved ...
win/win.

------
swampthinker
Could this technology be used for measuring water flow in pipes?

~~~
rscho
Absolutely, given the pipe is transparent to the ultrasound signal. Actually,
it is a well-known technique (see for example
[http://www.sensorsmag.com/sensors/acoustic-
ultrasound/ultras...](http://www.sensorsmag.com/sensors/acoustic-
ultrasound/ultrasonic-flowmeter-basics-842)), because if the angle of
incidence of the ultrasound beam to the pipe flow velocity vector is known
(which is not the case with blood vessels), the problem becomes trivial.

------
davak
Do you have hardware or can you let me know hardware you are currently using?

~~~
rscho
The soft is coded in Java (source code available on the linked website). As
for hardware, I had no choice other than using the S-video output of a
clinical ultrasound machine (Sonosite-S) through a frame grabber card
([http://www.hauppauge.fr/site/products/data_hvr1975.html](http://www.hauppauge.fr/site/products/data_hvr1975.html)).
The signal processing was done on a standard laptop from 2010.

The problem in using a clinical machine is that we had no access to the
internals, and the video output was an interlaced PAL signal, which translated
to a raw 100Hz 180*144 px numerical matrix, so the spatial definition could be
much improved by using a better machine. And of course, getting access to the
machine internals would allow the use of an optimal software solution, which
we couldn't implement in our case.

~~~
jonbaer
I would be interested to see how well this algorithm would work w/ mobile
setups (ie: [https://www.clarius.me/aium-debut-
pr/](https://www.clarius.me/aium-debut-pr/))

~~~
rscho
This would definitely work, since the device has color flow Doppler, and the
performance of the whole thing would mainly depend on the performance of the
underlying machine (spatial & temporal definitions). Our solution was not
tested in the clinical setting yet, though. Thanks for the link!

