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Cheap Blood Clot Detection Device

Posted by kdawson on from the but-wear-your-helmet dept.

Gearoid_Murphy writes "The BBC details the news of a cheap handheld device to detect blood clots on the surface of the brain. The device uses infrared light to penetrate 3 cm into the body; light that has passed through clotted blood changes detectably. A doctor who is testing the device in India said, 'We found a 98% accuracy for showing blood clots or haematomas.'"

13 of 103 comments (clear)

  1. Woah.. by Thyrteen · · Score: 4, Insightful

    I have a feeling that some surgeons will be sleeping alot better post-operation when they can monitor something like this more effectively.

    1. Re:Woah.. by Thyrteen · · Score: 5, Insightful

      Although the CT Scan would be useful, you need to remember. Your friend has a brain tumor. They operate, and remove it successfully, and close the opening. At this point, you wait, and pray that there's no clotting. Perhaps if this probe could be attached (I don't see why not), for a night after surgery, if clotting starts, the surgeon could get a much faster start on the patient, rather than waiting for "symptoms" to occur. A CT Scan can be useful in determining a problem, but the constant monitoring is useful for a separate scenario.

  2. To stem the statistical comments: by cgenman · · Score: 4, Interesting

    Inevitably someone is going to say "Well yeah, that means 2% died. Rough lot of good that did them."

    Before that person is you, think of the 98% that lived. I bet they're pretty happy that their chances of detection and survival went way up. And if you were sitting on an operating table in rural India with a poorly underfunded doctor wondering what's going wrong with you, wouldn't you like to take those odds too?

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    The ______ Agenda
    1. Re:To stem the statistical comments: by pytheron · · Score: 5, Insightful

      To put statistics into perspective, you need to consider the following (for arguments sake).
      Say 98% lived with this new tech. What percentage lived without it ? Maybe 94%. You can't infer that the previous methods of detection/avoidance were mediocre just because the new method has a high success rate. The article certainly gives no comparisons.

      --
      "I am not bound to please thee with my answers" [William Shakespeare]
    2. Re:To stem the statistical comments: by Repton · · Score: 4, Interesting

      I'd also be interested in the false positive / false negative rates, and the overall rate of blood clots.

      Eg, suppose 1 in 10 patients develop blood clots under some circumstances. You could get a 90% accuracy by making a device that just reports "No clots" every time. If you're classifying 98% of clots as clots and 98% of nonclots as nonclots, over 1000 tests you'll have 98 blood clots correctly identified, 2 missed, and 18 nonclots misclassified as clots..

      (obviously I have no idea what the true rate of blood clots is)

      Of course, the engineers who made the device and the scientists who test it almost certainly know all this, so I'm not being particularly insightful. If they call it a breakthrough or think it will be useful, then they're probably right. We just can't tell either way from the article...

      ("Mainstream news article lacks useful details: film at 11!")

      --
      Repton.
      They say that only an experienced wizard can do the tengu shuffle.
    3. Re:To stem the statistical comments: by fukitznukin · · Score: 5, Informative

      The other way to look at it is to compare infrared to the current modalities. For example, MRI which provides very sophisticated images, picks up 96% of brain injuries including blood clots. However, this is a very expensive test and is time consuming. In my hospital, I can get a STAT MRI and a radiologist's report in 1-2 hours. If it's after hours, a team has to be called in to do the test and then you can add at least another 45 minutes. Infrared testing on the other hand is a bedside test that can be done very quickly and inexpensively. From a general perspective, 98% is not just adequate it is much better than most tests used in medicine. An EKG that is done for heart attacks for example can miss up to 50% and most people are relieved when they are told that the EKG is normal. 98% accuracy is almost unheard of in medical testing. The term accuracy includes the effects of false negatives and false positives so 98% accurate does not necessarily mean that 2% of the true positives are missed, the test could be picking up all the true positives but also some false positives (it overcalls the number of abnormal test results). Additionally, a test that is 98% accurate does not mean that 2% of the people die unless of course you are referring to a uniformally fatal disease of which blood clots on the brain do not belong. A subdural hematoma is one type of blood clot on the brain and its mortality is about 60%. Additionally, if you think about it, the 2% of blood clots that are going to be missed (let's say the miss rate is 2%) will be the smallest 2% of the blood clots and therefore the least lethal. Yes, size does matter when it comes to blood clots on the brain.

  3. Company Website... by appleguru · · Score: 4, Informative

    http://www.infrascanner.com/

    Looks like they're based in PA, USA... But due to US regulations, they aren't allowed to test the device on patients in the US, and have outsourced such clinical testing to India.

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    appleguru.org
    1. Re:Company Website... by maxume · · Score: 4, Funny

      The bastards, sending a device they believe will work to hospitals with no alternative just because there is less government interference. I bet they kick puppies too.

      --
      Nerd rage is the funniest rage.
  4. Re:I wonder by j79zlr · · Score: 5, Funny

    I've been having massive headaches during and after sex.
    Its called guilt, you shouldn't masturbate that many times a day.
    --
    I'm not not licking toads.
  5. A marvelous invention! by Cathoderoytube · · Score: 4, Funny

    I have to say as a blood clot sufferer this invention sounds great. For those of you who don't know the previous means for checking for blood clots was to drain out all the patients blood and let it settle, then the doctors would count the blood clots floating on the surface. On one occasion my doctor accidently dropped his pen in the vat, then he tried to fish it out. I went completely spare and told him if he expected to put that blood back in me after he'd been sloshing around in it he had another thing coming.

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    I have nothing compelling to say
  6. The Slashdot blood test by Anonymous Coward · · Score: 5, Funny

    for your insensitive clots.

  7. How it works by c_fel · · Score: 4, Informative

    Hemoglobin has a different absorption spectrum when it's oxygenated (oxyhemoglobin) or not (desoxyhemoglobin). An interesting characteristic of this spectrum is observed in the near-infrared part or light (700-850nm): http://omlc.ogi.edu/spectra/hemoglobin/index.html

    In the infrared part, oxyhemoglobin absorbs less light than desoxyhemoglobin ; it's the contrary in the red part. So if we shoot these near-infrared wavelengths (and some more, to get a good idea of the absorption spectrum) in the head and detect it somewhere else (around 5-6cm from the source), we can get information on the concentration and oxygen level of the hemoglobin in the middle of the emitter and the detector. If the hemoglobin is more present than somewhere else in the head, and it's less oxygenated than usually, we get a good idea that there's something wrong there.

    Other advantages : infrared light is non-ionizing, so it's absolutely no dangerous to use that kind of instrument continuously on a person until we are sure there's no problem.

    It's brilliant and I'm glad to see that kind of instrument emerging.

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  8. Errr... by Anonymous Coward · · Score: 5, Informative

    I don't entirely agree...

    Aside from the fact that a lot of the time, we're more worried about post-op *bleeding* (which we'd see on CT) than simple clotting, I'm not sure how you'd tell appropriate clotting from dangerous clot, *except* through monitoring symptoms. Its not the clots after surgery that are dangerous, but when the clots are in areas that suffocate healthy tissue (ischemia).

    And a CT looking for new infarct would be useless. An MRI might help, but not a CT.

    And, yes, IAAD.