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Cheap Blood Clot Detection Device
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.'"
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]
I'm not not licking toads.
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.
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.
for your insensitive clots.
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.