4 ms·

Show HN: A software solution to ultrasound blood flow monitoring

85 points by rscho 10y ago

rscho 10y ago
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 10y ago
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 10y ago
  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 10y ago
Can something like this be used to detect (and prevent) DVT?
- rscho 10y ago
  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 10y ago
    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 10y ago
      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.
swampthinker 10y ago
Could this technology be used for measuring water flow in pipes?
- rscho 10y ago
  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/ultrasonic-flowmeter-basics-842 http://www.sensorsmag.com/sensors/acoustic-ultrasound/ultras...), 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 10y ago
Do you have hardware or can you let me know hardware you are currently using?
- rscho 10y ago
  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 10y ago
    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 10y ago
      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!
  - agumonkey 10y ago
    How common are Ultrasound machines with digital output on the field ? I guess there are models with DVI/HDMI/DP in catalogs already.
    - 10y ago

85 points by rscho 10y ago

rscho 10y ago

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 10y ago

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 10y ago
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 10y ago

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

rscho 10y ago
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 10y ago
  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 10y ago
    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.

swampthinker 10y ago

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

rscho 10y ago
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/ultrasonic-flowmeter-basics-842 http://www.sensorsmag.com/sensors/acoustic-ultrasound/ultras...), 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 10y ago

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

rscho 10y ago
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 10y ago
  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 10y ago
    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!
- agumonkey 10y ago
  How common are Ultrasound machines with digital output on the field ? I guess there are models with DVI/HDMI/DP in catalogs already.
  - 10y ago