|
|
Post by fascinating on Jan 20, 2017 10:12:38 GMT 1
Great news about the use of MRI being better than biopsy for detecting prostate cancer.
I wonder, is there a limit to how good we can make an MRI scanner, can we make them so we can view individual cells, or even organelles?
|
|
|
|
Post by alancalverd on Jan 20, 2017 19:51:09 GMT 1
Probably not. To improve spatial resolution you need a higher primary magnetic field and faster gradient slew rates. You can do a lot with very small MRI systems - we have excellent rat images at 7T primary field - but making a device big enough to accommodate a human is a significant engineering exercise. Practical resolution of a few tenths of a millimeter will show almost anything of clinical significance.
Commercial break!!!! Upright MRI scanners can give you a good image of the prostate without having to shove a radio receiver up your arse.
|
|
|
|
Post by fascinating on Jan 20, 2017 20:30:53 GMT 1
So you are saying that resolution of some few hundred micrometers is very possible?
|
|
|
|
Post by alancalverd on Jan 21, 2017 10:42:46 GMT 1
50 - 100 micron voxels are feasible with current systems but practical resolution beyond that is limited by the fact that the damn patient is alive. MRI image acquisition is a fairly slow process and even when gated to synchronise with pulse and breathing, there is often a gross muscular relaxation that blurs the image. 10 micron or even 1 micron is possible with a dead rat, but a knife and microscope is even better.
|
|
|
|
Post by fascinating on Jan 22, 2017 9:45:51 GMT 1
Many thanks for you learned input Alan. It's great that we have a real scientist/engineer on this board.
Is a voxel something like a pixel? Also what's a standing MRI? What's the advantage over the lie-down version?
I don't understand how "gross muscle relaxation" can be a problem, that surely would mean less movement and a less blurred image. Presumably with a dead body, with "absolute muscle relaxation", the images would be much better.
Sorry for so many questions but I think MRIs are so bloody marvellous.
|
|
|
|
Post by mrsonde on Jan 22, 2017 10:47:04 GMT 1
Many thanks for you learned input Alan. It's great that we have a real scientist/engineer on this board. There are several, even the majority, especially if you count the members bullied into silence by those like you who aren't. Respiration. |
|
|
|
Post by alancalverd on Jan 22, 2017 19:17:25 GMT 1
A voxel (volume element) is a 3D pixel.
Even with a patient lying down, and in the bits that don't breathe or pulse much (e.g. thighs) the relaxed shape changes slowly under gravity. Dead bodies flow less.
The problem we have in my upright MRIs is that they are so quiet that a seated patient can fall asleep: flowing and twitching degrade image quality, so we have to wake them up to keep them still!
|
|
|
|
Post by jean on Jan 22, 2017 23:16:09 GMT 1
...It's great that we have a real scientist/engineer on this board. There are several, even the majority, especially if you count the members bullied into silence by those like you who aren't An extraordinary claim! It's true that there have been some real scientists on this board - but the bullying directed at them came from one who fancied himself a philosopher.They stopped posting in disgust. |
|
|
|
Post by fascinating on Jan 23, 2017 9:22:01 GMT 1
I just decided to ignore that nonsensical remark, Jean.
|
|
|
|
Post by alancalverd on Jan 23, 2017 12:55:15 GMT 1
Being bullied by a philosopher must be a bit like being savaged by a dead sheep. The essence of philosophy is surely "we can't know anything" so those who do know a lot, just walk away.
|
|
|
|
Post by fascinating on Jan 23, 2017 20:39:28 GMT 1
|
|
|
|
Post by Progenitor A on Jan 23, 2017 20:43:19 GMT 1
It's true that there have been some real scientists on this board They stopped posting in disgust. And how do you judge a 'real scientist ' on this board? I suggest that it is totally outside your competence in the absence of access to qualifications and published papers/books Probably those people that you like or (the same thing) lefties that use scientific -sounding language  |
|
|
|
Post by fascinating on Jan 24, 2017 10:40:58 GMT 1
Oh here we go, anyone you deem to be a "lefty" can't know what a real scientist is, because they - supposedly - don't know anything about science.
First, a person can have an opinion of someone's professional capability without having any real knowledge of that profession; I can know who is a real doctor without knowing much about medicine, I can know that the guy who put in my shower is an electrician, I can know that Brunel was an engineer because some of the things he had built are still in use, even though I have no knowledge of that subject myself.
It was me who said "real scientist/engineer" when referring to Alan Calverd, who has a Phd in Physics and is directly involved in the design and build of MRI scanners. You probably class me as a lefty, and therefore would deny that I have a right to an opinion that Alan Calverd is a scientist/engineer, but nevertheless, that IS my opinion.
It was mrsonde, qualified in PHILOSOPHY, who said that there are several scientists. Jean agreed with that, but took issue with his outlandish claim that they had been bullied into silence.
I suggest your posting is just having a go at Jean because you hate her, without discussing the actual issue at all.
|
|
|
|
Post by jean on Jan 24, 2017 15:25:16 GMT 1
He loves me really, as does Nick.
They just can't bring themselves to admit it.
|
|
|
|
Post by alancalverd on Jan 24, 2017 15:37:37 GMT 1
It was me who said "real scientist/engineer" when referring to Alan Calverd, who has a Phd in Physics and is directly involved in the design and build of MRI scanners. You probably class me as a lefty, and therefore would deny that I have a right to an opinion that Alan Calverd is a scientist/engineer, but nevertheless, that IS my opinion. And I'm also a communist and an entrepreneur. You just can't believe anything these days, can you? |
|
