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One whole-body MRI could replace multiple cancer scans

pharmatimes.com

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Re: One whole-body MRI could replace multiple cancer scans

#101

Post by abecedarius »

arkades wrote: post #76
MegaButts wrote: post #57

Earlier quoted context omitted.

But doesn't this approach make it nigh impossible to catch people that don't fit the mold? It almost seems like it becomes a tautology, by not capturing the diseases in people you don't think have them, and only looking in people that you do think have them. And the only way to change the mold is for enough people to likely die that you reevaluate the model. I am not a doctor, but I cannot fathom why a doctor would e…

Well, that’s part of why there’s constant research into what risk factors / predictive factors are. These aren’t mutually exclusive activities. “Data” implies something neutral. Nothing about lab tests is neutral. Without contextual information and studies on how to -interpret- a finding, it’s just potentially terrifying noise. And terror usually results in action. Poorly informed action is often harmful. So... we ar…

For a rational agent the expected value of information is never negative. (Of course it can be less than the cost of the test.) If a system is treating it as negative, that's a problem to fix.

I'm reminded of a recent visit to a doctor who refused to say anything quantitative about a test. Sure, your average client knows little decision theory, but this doctor either didn't either or pretended not to follow. To make a good decision you need both probabilities and utilities; the doctor presumably best knows the former while the client best knows and cares about the latter, so they need to be able to communicate this way.

Re: One whole-body MRI could replace multiple cancer scans

#102

Post by jashephe »

chongli wrote: post #23
nknealk wrote: post #13

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.

This 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?

Some 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.

Re: One whole-body MRI could replace multiple cancer scans

#103

Post by jashephe »

whatshisface wrote: post #35
nknealk wrote: post #13

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.

Why 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?

Some folks have raised plenty of practical/medicolegal reasons, but it's also worth noting that patients are often not comfortable being told that they have an "anomaly" that their doc is going to sit back and do nothing about. There's a lot to be said for the psychiatric implications of being aware of benign MRI findings.

Even if you (or anyone, for that matter) might be comfortable with that, I think you'd find that a lot of patients wouldn't be.

Re: One whole-body MRI could replace multiple cancer scans

#104

Post by mattkrause »

stevesimmons wrote: post #92
chongli wrote: post #23

Earlier quoted context omitted.

This 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?

Even 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.

Nope. 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!

Re: One whole-body MRI could replace multiple cancer scans

#105

Post by ohithereyou »

jashephe wrote: post #102
chongli wrote: post #23

Earlier quoted context omitted.

This 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?

Some 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.

I 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.

Re: One whole-body MRI could replace multiple cancer scans

#106

Post by matwood »

jashephe wrote: post #102
chongli wrote: post #23

Earlier quoted context omitted.

This 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?

Some 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.

I 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.

Re: One whole-body MRI could replace multiple cancer scans

#107

Post by mattkrause »

jashephe wrote: post #102
chongli wrote: post #23

Earlier quoted context omitted.

This 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?

Some 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.

This!

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.

Re: One whole-body MRI could replace multiple cancer scans

#108

Post by ChrisLomont »

DuskStar wrote: post #94
ChrisLomont wrote: post #81

Earlier quoted context omitted.

The link states "As a result, in our study the maximum hours per week on each scanner was limited to 35 h for the Vision (no hours on Tuesdays), 39 h for the Harmony, 32 h for the Sonata (no hours on Wednesdays) and 38 h for the Avanto." Why guess 67 when you can look at the answer?

Because from my reading that's not the number of hours they used the machines, but the number of hours in which the machines were available to be used. And since they also state that their utilization figures only include emergency cases (and exclude scheduled scans) I don't consider it a particularly relevant source in the first place.

>I don't consider it a particularly relevant source in the first place.

Care to provide a relevant source?

Re: One whole-body MRI could replace multiple cancer scans

#109

Post by arkades »

abecedarius wrote: post #101
arkades wrote: post #76

Earlier quoted context omitted.

Well, that’s part of why there’s constant research into what risk factors / predictive factors are. These aren’t mutually exclusive activities. “Data” implies something neutral. Nothing about lab tests is neutral. Without contextual information and studies on how to -interpret- a finding, it’s just potentially terrifying noise. And terror usually results in action. Poorly informed action is often harmful. So... we ar…

For a rational agent the expected value of information is never negative. (Of course it can be less than the cost of the test.) If a system is treating it as negative, that's a problem to fix. I'm reminded of a recent visit to a doctor who refused to say anything quantitative about a test. Sure, your average client knows little decision theory, but this doctor either didn't either or pretended not to follow. To make…

Cool, so your serum zorblaxian levels are 300 ng/L. The finding was incidental, so it’s jot tied to existing symptoms / clinical suspicion. It’s a molecule involved in the inflammatory cascade. We don’t know what diseases it’s associated with or not, nor what the change in probability of having the diseases it could be associated with are, not change in prognosis. But, you have a number which your local lab pegs at 1 standard deviation above the mean for the sample they calibrated their measurement technique on.

So, should we now do a work-up for every disease known to man with an inflammatory component? If you have one, if, every test - with their attendant complications and costs - for every disease you don’t have will have net negative effect on your health. You baseline have no symptoms or clinical suspicion for any of these (again, tautology or incidental finding), so the baseline probability is you actually have no disease at all, and this is a spurious value. So, what’s the advantage of this incidental finding?

Re: One whole-body MRI could replace multiple cancer scans

#110

Post by [deleted] »

nknealk wrote: post #13

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.

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