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Many doctors hate full body scans. Every individual has a handful of anomalies which are almost always benign. They show up on full body scans and chasing them
by nknealk 7y ago
Many doctors hate full body scans. Every individual has a handful of anomalies which are almost always benign. They show up on full body scans and chasing them down comes with cost and patient risk.
I have a hard time with reporting like this that doesn't quantify cost of biopsy on false-positives as well as cost of complications from examining false-positives.
Source: worked in clinical research for 2 years.
- chongli 7y agoThis sounds to me like doing a full workup on blood chemistry. Individuals vary so much that you can get false positives. Wouldn't it be more useful as a baseline? Scan once and store it, then scan every few years and compare. If any of the "anomalies" has grown or new ones have appeared between scans, then they might be worth a second look?
- petschge 7y agoGetting a baseline is harder than it sounds. In the case of blood chemistry that is caused by fluctuations due to time of day, time of month, season, what you recently ate and so one. In the case of MRI the problem is that internal organs shift to the point that it is impossible to automatically compare. And a experienced doctor comparing the scan millimeter for millimeter takes hours and would be very expensive. Even just tracking the volume of a known tumor in the brain (that shifts very little) to track the effect of radiation is tedious, time consuming and error prone.
- duxup 7y ago> internal organs shift to the point that it is impossible to automatically compare I didn't even know that is a thing, I just sorta assumed they stayed put.
- rolleiflex 7y agoYou are a wet squishy clump of really advanced bacteria trying their damned best to physically hold together, barely alive. Don’t expect much. Human politics is the literal definition of shipping the org chart.
- pgeorgi 7y agoWhen undergoing abdominal radiation treatment, patients are asked to stop breathing to keep organs at their place (and not radiate healthy tissue), but apparently that still isn't good enough: https://www.ncbi.nlm.nih.gov/pubmed/27773445 https://www.ncbi.nlm.nih.gov/pubmed/27773445
- deleted 7y ago[deleted]
- cameronbrown 7y ago> internal organs shift to the point that it is impossible to automatically compare. Seems like a good area to apply machine learning if we had enough data?
- roywiggins 7y agoMRI scanners can only barely do quantitative evaluations... between different scanners, and different scanning protocols, your body may look quite a bit different and it is hard to know exactly how much variability to attribute to inter-scanner differences. There are whole studies done to try and quantify this, and it requires sending "human phantoms"- test subjects- around to different scanners, which requires you to physically take one subject around to several scanners operated by different people and stick them in there for a while. It's really involved.
- stevesimmons 7y agoEven if we can't reliably compare a time series of images today, wouldn't it be useful to start scanning now, for use as baselines in several years once the state of the art improves? In the same way astronomers can make new discoveries by digitizing photographic plates from a century ago.
- mattkrause 7y agoNope. Really, it's a question of priorities. Scanners cost a lot: ~4M for a 3T (the current 'standard') and much more for higher field strengths. We just got a 7T and, with all the trimmings (scanner, console, coils, the shielded room to hold it all, training, etc), it's in the $10-15M range. As a result, time on these things is already in pretty high demand, even at facilities that are used only for research. The projects could be reprioritized, of course, but most of the on-going research is much less speculative than "someday, this can be training data for something." It's not even clear to me that old MRI data will be particularly worthwhile. Photographic plates were, until recently, about as good as digital sensors. New MRIs are much, much better than old ones, and the tech will only improve more. Longitudinal data is useful in both fields, but for astronomy, there's no way to rewind time, so old plates are the only possible source for events from the past. We get new old people, however, every day!
- copperx 7y ago> We just got a 7T Where is that? Might be worth the trip in some cases.
- mattkrause 7y agoI'm in Montreal, but 7Ts are popping up all over, especially now that Siemen's Magnetom Terra got FDA approval. I know Yale also has a 7T, as does the NIH, Stanford, and MGH (I think--it's somewhere in Boston). The University of Minnesota has THREE which is crazy.
- jashephe 7y agoSome of the comments here don't touch on the practical limitations of this, but here's one — I'm at a 1400+ bed top-10 US academic medical center, and even our outpatient MRI machines book patients until near-midnight because the scans take so long. I'm not sure if we even have the imaging capacity at this point to be scanning healthy people.
- ohithereyou 7y agoI work for a company that makes MRI machines. There is an industry wide push to reduce scan times. Even a 30 second or one minute reduction on scan time per protocol can translate into one or two more scans a day. Across a fleet of scanners, this can be millions of dollars a year in revenue. There are hospitals that have switched brands of scanners over protocol times.
- matwood 7y agoI don't know if they are high enough quality for a full body scan, but there are MRI places literally in strip malls now. Cash price for a back scan is ~$350.
- mattkrause 7y agoThis! I got up at 4am to run scans in grad school because the even the research scanners were booked solid, never mind the clinical ones. Scanners are really expensive: the machine costs a lot, it needs fairly particular conditions (shielded room, cryogens), and trained operators and analysts. There's maybe a market for fleecing the extremely wealthy into undergoing MRI fishing expeditions, but you'd have to charge a fortune if you're going to buy scanners to do it.
- xvilka 7y agoNations like Japan, China are pushing MRI resolution and speed, along with lowering the costs. Particularly because the average people getting older, thus diagnostics will reduce the cost of healthcare on the long run, on the scale of these countries.
- 300bps 7y agoSimilarly, the doctor who discovered Prostate Specific Antigen regrets that is used to screen for prostate cancer because of its inaccuracy, questionable benefits and substantial harm created by biopsies and treatment of prostate cancer: https://www.nytimes.com/2010/03/10/opinion/10Ablin.html https://www.nytimes.com/2010/03/10/opinion/10Ablin.html
- andreygrehov 7y agoOff-topic, just spreading knowledge. Check out IsoPSA [1], which is a simple blood test procedure superior to PSA (unfortunately, not available in US, yet). [1] https://www.cleveland-diagnostics.com/isopsa https://www.cleveland-diagnostics.com/isopsa
- aitchnyu 7y agoWhy do doctors advocate less frequent scans when they see that frequent scans creates false positives? Can a metric be invented such that a doctor can make a solid decision "I'm 99% sure this wont kill you in two years" and leave the tumour alone?
- JamesBarney 7y agoI imagine there is a lot of non-optimal decision making going on the patients side because of the emotional salience of cancer, and on the doctors side because of lawsuit risk.
- arkades 7y agoWe don’t advocate less frequent scans, we advocate targeted scans. Because the probability of a positive result being a false positive depends heavily on the population. In a population with a high baseline frequency, the probability of a positive being false is relatively low; in a population with a low baseline frequency, the likelihood of a positive being false is relatively high. So, you don’t mammogram every person with a breast. You mammogram people with advanced age, genetic predisposition, etc. so as to select for a population with a reasonable baseline frequency. Various professional bodies and the USPTF put a lot of effort into determining what the optimal screening population is. Clinical decision rules are an extremely active part of medical research. Trying to figure out a reasonable predictive model to say “definitely follow up on this” or “definitely don’t” is a huge field in medicine. For instance, in patients ≥35 years old with incidental pulmonary nodules on CT imaging, we have the Fleischner Guidelines for when and which follow-up is appropriate. But it required a number of prospective external validation studies in order to properly validate it, and it’s for one super specific population: under-35 incidental pulmonary nodule on non-cancer-screening CT. So, you can imagine how much work there is to be done for the other 10,000 kinds of incidentalomas.
- jcims 7y agoSitting in the oncology dept right now with my wife who’s gaving complications from a tumor. I’d just be happy with peer reviews of radiology reports so fuckups don’t cost us three months of potential treatment. I’m sitting bedside wading through pull requests for software installation scripts. How is it the opinions of folks on my team for a bullshit process get more scrutiny than a potentially life-altering assessment that requires expertise, a keen eye and sharp mind every time?
- amluto 7y agoWhy is this an issue with testing rather than an issue with the conditions under which treatment is given? In other words, ISTM the problem isn’t with a full-body scan per se. The problem happens if every little thing found gets treated or tested invasively.
- wolco 7y agoLimiting patient information for fear of false positive seems like a backwards step.
- whatshisface 7y agoWhy can't a doctor see an anomaly and decide not to chase it down based on the same reasoning that they use to not scan for it? Is there some pointless legal trap related to malpractice where the only allowable "don't operate" decision happens when the doctor decides what to test for?
- arkades 7y ago(1) Because we do not have the body of knowledge that tells us how to predict an anomaly is not worth pursuing. It would require a lot of major, expensive, long-term studies involving non- negligible chemical exposures in$ asymptomatic people in order to get a good idea of what the “healthy” anomaly looks like. $ many of these MRIs require contrast material. (2) Malpractice for a missed cancer in most states has an enormous lookback period and an automatic “doctor loses.” It doesn’t matter if the doc made a statistically appropriate call. So docs follow-up on anything but the most unambiguously benign lesions.
- internet_user 7y ago> statistically appropriate call. but factually incorrect call is apparently OK, because they are treating "median person", and not the actual patient. This has to do with money - and nothing else.
- arkades 7y agoNo, it has to do with avoiding harm to patients. I don’t make one red cent more or less from sending someone to an MRI or not. I do care about wasteful testing that is more likely to stress out a patient and send them down a rabbit-hole of follow-up tests with potential complications and costs (to them), if there’s not a reasonable chance of an outweighing clinical benefit for them. And of course we make statistical calls! When you’re deciding -prospectively- whether a course of testing or treatment is in a patient’s best interest, you have to look at the stats on likely benefits and harms of various courses of action. I’d love to know what my patients have before hand, so I could avoid dealing with probabilities, but I haven’t been blessed with that particular power. I’d love for the data to exist to tell me how to interpret a result in my precise patient rather than a larger population she belongs to, but “solitary pulmonary nodules in 33-year old men who smoked twice in college and live half a mile from a freeway with two episodes of bronchitis in their teens” is a study that hasn’t been conducted yet. One day perhaps it will be, and if so, I’ll be grateful for it. But right now that data doesn’t exist, so we use what we have, and use our judgment to tailor it to the patient in front of us - imperfectly. I recommend reading “overdiagnosed” by Gilbert Welch.
- mcphage 7y agoIt seems like the solution to this would be more frequent scans, so doctors can determine what's a static anomaly, and what is actually changing over time.
- paulsutter 7y agoYou're describing a problem with the doctors, not a problem with the scans. I'm curious to understand the real motivation to avoid information. Is it something in the system, litigation risk? There are many ways to deal with incidentalomas. If full body scans were more widespread, maybe doctors would have confidence to deal with them properly. For example, watching them over time.
- deleted 7y ago[deleted]
- canada_dry 7y ago> watching them over time In my mind this is the key... a way to frequently and conveniently do a full body scan so that anomalies can be detected via the delta. Scanning and detection is a problem that likely could be tackled via machine learning. I'm hoping it's not too long before a method is developed where a low res MRI like scan is feasible at home (e.g. using radio or ultrasound). Done on a regular basis the system could detect anomalies like the appearance or enlargement of a growth inside the body.
- koboll 7y agoThere is a point at which the radiation you're receiving from regular scans becomes harmful enough to outweigh the benefits of early detection.
- darkpuma 7y agoMRI scans do not irradiate people.
- petschge 7y agoObtaining the delta from two different images is actually non trivial. And contrary to what HN thinks, not every problem is trivially solved by machine learning. Small point aside: an ultrasound scan -- even if it was every feasible at home -- would not be an MRI. MRI means you use the spin echo and relaxation of nucleii (mostly protons for medical MRI). It is not a generic word for "please give me a 3d image". Words have meanings, especially when they are technical jargon, and it is important to not dilute that if we want to be able to communicate efficiently and effectively. Also: technology that is more mature than software tends to improve at a more measured pace, as all but the hardest breakthroughs have been obtained already. It is therefore unlikely that you will be able to replace a 10 million dollar machine by things in your home any time soon.
- fromthestart 7y agoSounds like prime territory for machine learning, though I don't know how much variance there can be in the presentation of anomalies and how much training data you'd therefore need. Do tumors from various cancers typically share any discernable features?
- orblivion 7y agoI think I was advised once not to take a test for Lyme Disease unless I had other fairly clear indicators because of the cost of a false positive.
- WhompingWindows 7y agoWhy not employ those fancy new neural networks for analyzing images? Have the doctor and the software identify anomalies separately and compare outcomes.
- SomaticPirate 7y agoBut this is exactly what an “executive scan” is. I know several CEOs who get full body scans. Two of them caught early stage cancers and credit these scans with vastly improving their prognosis.
- jmhmd 7y agoA counterpoint to these stories of early diagnosis is that not all cancers are equal, and there are some cancers which may not ever have affected the patient had they not been treated (or detected). Examples include some prostate and breast cancers. Autopsy studies have shown occult prostate cancer in about half of men > 70 years old who were asymptomatic and died of other causes. Of course it is often impossible to know which cancer will or won't kill you, but it should be recognized that there is a risk to scanning oneself without a proper indication, for example, getting a prostatectomy for indolent prostate cancer and risking impotence.
- zukzuk 7y agoIn Canada, these "executive scans" are a service sold by private clinics. As OP pointed out, they will often find things that are entirely benign. However, since in Canada you can't charge money privately for services that are covered under public insurance, guess who ends up paying for the bulk of the inevitable follow-up investigations coming out of these full-body scans that only the wealthy can afford.
- rolleiflex 7y agoA decent portion of my family are MDs. This is accurate. However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we do receive. A stream of known false positives is worth its weight in gold in any detection system, it's just that this specific system happens to contain squishy feely human doctors that are susceptible to short-term human 'Please don't spend more money than necessary, we're already in the red for this quarter' kind of pressures from their superiors. Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree, which would counteract the temporary cost increase in chasing false positives. The fact that we don't want to eat the short term initial cost means some of those things that could be uncovered by the scan, things that could save a person from a malignant deviation, is left unseen, untreated, to its natural end.
- internet_user 7y agoIt's just more profitable to fob off patients as fast as you can, good for business. In-depth investigations have massive opportunity costs for someone reimbursed on piece-work basis, takes up way too much time.
- aantix 7y agoThen more money needs to be charged or a refusal to perform them.
- jmhmd 7y agoThe idea that lots of full body MRIs will necessarily lead to better discrimination of malignant vs benign anomalies assumes that the imaging is able to detect differences at all, which often is not true. Some benign and malignant abnormalities can look _exactly_ the same on imaging, particularly at an early stage, when you could make a difference, for example lung nodules. Nevermind the fact that many benign entities can undergo malignant transformation at some point in the future. Or that MRI is only a good test for a subset of cancers, CT is better for others. All these issues help explain why doctors are averse to full-body scanning everybody. It is neither cost-effective nor medically sensible.
- internet_user 7y agoIt is so much more efficient to tell people to go home and rest. That way you can triple book and make 3x the money. Insurance reimbursement is exactly the same for your appointment, regardless if the patient lives or dies, or even gets correct diagnosis, nevermind correct tests. /s
- willwagner 7y agoI've heard this many times before and don't doubt thats the way doctors feel but it's a little like not monitoring production because you don't want developers chasing down minor production issues.
- skwb 7y agoExcept there's an entire literature of false positives and the costs associated with these detections [1]. Costs here include not only direct financial costs of potentially unnecessary surgical procedures, but include everything to additional complication due to treatment and patient emotional grief/loss of earnings due to aggressive care. The lesson a lot of people who are not familiar with public health is that you need to sorta take the long view for these things since we don't make rational decisions. To bring back your analogy, it's then sorta like requiring an all hands meeting every time your IDE catches a typo. It's still monitoring a something that MAY cause a problem in the future, but to a good enough degree the costs associated with monitering may not be relevant to your actual end goals. [1]. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079487/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079487/
- deleted 7y ago[deleted]
- nnq 7y agoMDs are idiots in this regard. Mainly because they've been thought medicine by other idiots. They have this stupid idea that "too much data" is bad, also stuff being a sign that you're a bad doctor if you order too much tests etc. It's a whole can of worms of crappy rationalizations here, that also hides the fact that doctors are not capable or trained to correctly deal with large volumes of data, so they know they will make mistakes that they will be liable for if they are handed more data! More data is always better. Period. Problem is that we lack some kind of protocols of "calculated ignorance" that they could follow, like be allowed to ignore large classes of semi-normal findings that would show up often and lead people on wild goose chases, and be safe from malpractices and stuff if they follow this "calculated ignorance". This is because in the end medicine is not about doing "the best thing at all cost", but at doing the best thing that can be done at population scales, under limits of financial cost and "comfort cost" (there are limits after most of us would prefer (high risk of) death instead of further investigations and treatments and these limits vary (wildly) by individual). There's two things that should be drilled down into the heads of all domain experts: (1) more data is always better, and (2) it's ok to ignore as much of the data as you want if it doesn't make sense cost-wise to investigate it further. But it's always better to fish in a larger lake!
- louden 7y agoMore data is not always better. The collection process itself can be dangerous or unpleasant for the patient. Several years ago I worked on a study looking at the spread of bacterial lung infections in long term hospital patient. In order to get the data, we would have to intubate patients that did not need it. In this case, the people who approve these studies rightfully ruled that getting that data would be too painful for the patients to allow. Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course).
- Brakenshire 7y ago> The collection process itself can be dangerous or unpleasant for the patient. That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous. > Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course). Both need to be judged on time and cost, but only the biopsy needs to be weighed against risk, not the scan. If people see a scan with anomalies and want dangerous procedures even if the risk is not demonstrated that is a cultural, education, and legal problem. Both for doctors wanting to avoid malpractice ordering unjustified tests, and for patients “wanting it out”. But if the scan can demonstrate some marginal elevated risk, not the need for immediate intervention but for increased screening, that data could potentially save many lives, and it should be used, not hidden away because of the possibility of overreaction. Researchers need to find how best to use the data and patients and doctors need to be educated in our current best understanding, not pandered to.
- nathan_f77 7y agoWhat about having regular full body scans and tracking any anomalies over a period of months or years? You could safely ignore anything that doesn't change, but you would immediately spot any fast growing cancers before it's too late.
- m463 7y agoDentists don't have any trouble taking regular full-mouth x-rays. Maybe this is because this translates into money for each problem found. In the same way, skin doctors take photos of body moles to see if any changes occur between visits. I think internal doctors should start viewing this as inevitable. Then up-front develop "watchful waiting" plans that over the course of time and several scans chase down any suspicious changes.
- Flemlord 7y agoWouldn't you compare back to an original/baseline scan, making it easy to ignore anomalies?
- jwr 7y agoI always found this approach strange. It's like closing your eyes and pretending you don't see parts of the patient's body.
- kurthr 7y agoThe use case I can see is a healthy-before/after-sick... all those benign growths you're worried about seeing, will not change between scans. What will change/grow/shrink? Things you might might want to look at as causes of your illness. Ignorance is bliss until you miss that easily removed tumor... etc and you are stage 3 going for chemo, or a brain anurism...