Thursday, 6 July 2017

Is SWI part of standard MRI imaging?

I recently read that SWI can reliably determine regrowth from pseudo-recurrence. If this is the case why are there so many concerns about pseudo-recurrence? Is SWI not used standardly? Does it have pitfalls? Does it require use of contrast agent? (I haven't had MRI with contrast yet, due to pregnancy, so I'm wondering about "establishing a baseline" from which to measure my tumour going forward.)

2 comments:

  1. I believe SWI falls into the 'advanced imaging' category and is not part of standard practice. There are a couple hurdles for new imaging methods to get implemented.

    1) Like drugs it generally requires clinical trials to prove effectiveness and sufficient accuracy. Ie can't have a new method that 25% of the time would cause oncologist to go into surgery only to find out it was a false positive.

    2) Equipment limits. Most of the newer imaging is done with the stronger 3Tesla MRI units that are not very common vs the standard 1T or 1.5T machines. Also the 'protocol' for a new imaging method is both a set of hardware requirements, driver software and data post processing software. All that is licensed and expensive.

    3) Insurance limits. Even if a new tool/drug/etc gets approved insurance companies don't necessarily cover it.

    4) True useability of the method. For high grade the new imaging methods generally work, but for lower the grade tumors the new methods like SWI, DTI and MR spectroscopy are still semi-marginal in being able to robustly detect changes.

    The result is that a lot of possible imaging options don't get made available to a regular patient, at least without both a) being at an BT center and b) pushing hard with your NO to try.

    Its also feasible is to get into a clinical trial for the newer methods. One I'm pretty interested in is with UTSouthwestern using MR spectroscopy to look at metabolites and in particular to measure 2-HG levels (trial # NCT02388659). Similar work is being done in trials with IDH1 inhibitors like Agios's line of drugs.

    But overall it seems like with new drugs, the medical establishment is slow to embrace new imaging techniques.

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    Replies
    1. Thank you. I was beginning to suspect some of this based on the numerous studies trying to justify its use. Very informative response, thank you.

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