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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.'"

19 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. Re:Woah.. by TheLink · · Score: 3, Insightful

      The wait for a CT scan could be too long. There can be far more of these devices than CT scanners.

      This will help determine if patients need immediate attention.

      As long as the false positive rates aren't high and this device is sensitive enough to detect the common cases, it will be useful.

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    3. Re:Woah.. by Silver+Gryphon · · Score: 3, Insightful

      Since the CT scan is expensive, time consuming and often has an hour-long wait even in emergency rooms, they now use the CT scan only if they are fairly certain there's a problem and are often discouraged from doing more than one a day on a single patient. A device like this could be used like the O2 Saturation monitors or cardiac monitors: preventative, non-invasive and don't require scheduling of the million-dollar equipment.

      I can see this tech being used some day to detect clots in legs, arms, etc.

    4. Re:Woah.. by clickclickdrone · · Score: 3, Interesting

      Well, India, rather than England but if it does the job... Heck in the UK they still use leeches c/o the NHS and it's not uncommon to use maggots on badly infected wounds because they eat the bad stuff and leave the good stuff far better than any other treatments. Just because something sounds medieval, don't write it off.

      --
      I want a list of atrocities done in your name - Recoil
  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?

    --
    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 Anonymous Coward · · Score: 3, Informative

      In fact, they are using CTs to confirm the diagnosis...so the implication is that the hand held device is missing 2% of the cases that the CT is catching...at a great cost savings (what was that speech from fightclub about the recall formula?)...that might be the reason why the device isn't cleared for use in the states.

    3. 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.
    4. 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 Reader+X · · Score: 3, Insightful

      One wonders what other such testing is 'outsourced'...

    2. 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.

    --
    I hate all sigs, mine included.
  8. Cheap?! by quarrel · · Score: 3, Funny

    Oi!

    Who are you to call my blood clots cheap?!

  9. 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.