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Tracking muscle fascicles through ultrasound ! - Jul 12 at 11:22AM
Georgios M
2 Posts

Hi everyone !

I am trying to measure muscle fascicle length changes during active contractions using Tracker. I want to configure tracker so it can track a muscle fascicle and measure how its length changes during movement (an example so you can understand https://www.youtube.com/watch?v=8lTp_7tHOlQ ). In the videos that I provide bellow you can see the muscle fascicles, the superficial and the deep fascia (take a look here to understand the terms http://imgur.com/a/GTe4x ). I can understand that the quality might be poor to track a single fascicle as they seem to disappear, but if you look closely the superficial fascia seems not to move while the deep fascia moves a lot. Ultimately what I want is to measure the horizontal (and also vertical) movement of the deep fascia so to calculate how much the fascicles elongated. Is there a configuration to track the movement of the deep fascia ?

Now as an additional point, I am aware that the video margins are not big and a lot of the fascia moves out of the screen. For that reason I will probably track point A (in the picture http://imgur.com/a/GTe4x ) measure its distance from point B, and then once point A leaves the screen to measure how much did point B move so as to calculate the distance that point A moved (assuming the distance between the two points does not change).

Here is a a better quality video but with lower framerate (44 Hz).
https://www.youtube.com/watch?v=x4QgCWtC6Lg


Here is a low quality video but with high framerate (117 Hz).
https://www.youtube.com/watch?v=Lkc6v9hZxb4

I could send you the video files if you cannot download them from youtube. Could you please play a bit with those two videos and tell me if you have found a way to successfully track the fascicle length changes ? Ultimately what I want to measure is how much the deep fascia ( the middle white line you see in the video) is moving.

Thanks,
Georgios


Replies to Tracking muscle fascicles through ultrasound !

Re: Tracking muscle fascicles through ultrasound ! - Jul 12 3:36PM
Douglas Brown Avatar
Douglas Brown
161 Posts

Georgios, tracking the deep fascia in your videos will be difficult but possibly doable manually, but the autotracker is not going to be able to help very much--there are just too many fascicles and other features that appear, disappear and/or wash out. I was able to track a few frames by making the shape of the template tall and skinny and positioning it so it stretched across several fascicles, but even then it is hard to tell if it really tracked the true motion of the deep fascia.

You should consider tracking the deep fascia not as a point mass but as the origin of the coordinate system. That way you can create additional offset origins as you need them to continue tracking when the tracker origin goes offscreen. This accomplishes the same thing you described using points A and B but more directly.

Doug


> Re: Tracking muscle fascicles through ultrasound !
>
> Hi everyone !
>
> I am trying to measure muscle fascicle
> length changes during active contractions using Tracker.
> I want to configure tracker so it can track a muscle
> fascicle and measure how its length changes during
> movement (an example so you can understand https://www.youtube.com/watch?v=8lTp_7tHOlQ
> ). In the videos that I provide bellow you can see
> the muscle fascicles, the superficial and the deep
> fascia (take a look here to understand the terms http://imgur.com/a/GTe4x
> ). I can understand that the quality might be poor
> to track a single fascicle as they seem to disappear,
> but if you look closely the superficial fascia seems
> not to move while the deep fascia moves a lot. Ultimately
> what I want is to measure the horizontal (and also
> vertical) movement of the deep fascia so to calculate
> how much the fascicles elongated. Is there a configuration
> to track the movement of the deep fascia ?
>
> Now as
> an additional point, I am aware that the video margins
> are not big and a lot of the fascia moves out of the
> screen. For that reason I will probably track point
> A (in the picture http://imgur.com/a/GTe4x ) measure
> its distance from point B, and then once point A leaves
> the screen to measure how much did point B move so
> as to calculate the distance that point A moved (assuming
> the distance between the two points does not change)
>
>
> Here is a a better quality video but with lower
> framerate (44 Hz).
> https://www.youtube.com/watch?v=x4QgCWtC6Lg
>
>
> Here
> is a low quality video but with high framerate (117 Hz)
>
> https://www.youtube.com/watch?v=Lkc6v9hZxb4
>
> I could
> send you the video files if you cannot download them
> from youtube. Could you please play a bit with those
> two videos and tell me if you have found a way to
> successfully track the fascicle length changes ? Ultimately
> what I want to measure is how much the deep fascia
> ( the middle white line you see in the video) is moving
>
>
> Thanks,
> Georgios



Re: Re: Tracking muscle fascicles through ultrasound ! - Jul 20 7:20AM
Georgios M
2 Posts

Dear Doug,

Thank you for your reply and for developing such an amazing software !



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