GDC API: Obtain the Objective Power (or Magnification) of a WSI file

Question

[Martim]

I've been trying to find out a way to retrieve the Objective Power (or Magnification) of a Whole Slide Image file without downloading it first, using the GDC API.

I've seen that some WSI's Objective power might be 40x and others 20x, and I need a way to filter the ones I want to retrieve according with this parameter.

However, I cannot figure out the query I need for this.

Can anyone help me?

Answer 1

[Zhenyu Zhang]

There is a property called magnification on the slide image node. However, except a few slides from CGCI-BLGCP, most of the data submitters, including TCGA, did not provide such information to the GDC, so they mainly have no values.