# Segmenting on an oblique plane 2D image

**URL:** https://discourse.slicer.org/t/segmenting-on-an-oblique-plane-2d-image/14215
**Category:** Support
**Tags:** transforms, automation
**Created:** [October 23, 2020, 3:59pm UTC](https://discourse.slicer.org/t/segmenting-on-an-oblique-plane-2d-image/14215 "2020-10-23T15:59:28Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![Hapietsch](https://avatars.discourse-cdn.com/v4/letter/h/977dab/32.png) [@Hapietsch](https://discourse.slicer.org/u/Hapietsch)
#### Post date: [January 30, 2021, 5:40pm UTC](https://discourse.slicer.org/t/segmenting-on-an-oblique-plane-2d-image/14215/3 "2021-01-30T17:40:30Z")

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Hi Mr. Pinter.  
I’m having a similar issue, I think, based on the description. But the button suggested causes my screen just to revert back to the original slice, not the oblique slice I need.

I have a CT scan, and need to measure the area of the end plate on a vertebral body. The spine is not always in line with the orientation of the slice, so I used an oblique slice to view the end plate and take a measurement like so:

1. Reformat module - select red slice, then adjust A-P and L-R until the red slice is aligned as best I can
2. Markups module - draw a closed loop around the area of interest. Then use the code from Mr. Lasso in another question to calculate the area within the loop. [How can I calculate an area on a CT image. I can calculate volumes (mm^3) but not areas (mm^2) - #4 by lassoan](https://discourse.slicer.org/t/how-can-i-calculate-an-area-on-a-ct-image-i-can-calculate-volumes-mm-3-but-not-areas-mm-2/1549/4)

I would prefer to make a more consistent calculation based on threshold of the bone, vs my eye drawing a loop. I repeated the process a few times, and I get slightly different values. I have about 90 of these measurements to take, so I don’t want to introduce variation from my own ability to draw on the screen. And it’s quite a lot of measures to do multiple times and take an average.  
I was hoping to use the segment function for a single oblique slice. I have tried to take a segment on the oblique plane, but 3D slicer always shows the segment across all of the original slices when I try this. I get a short volume, rather than the 2D segment on the oblique plane.

I was hoping your solution to this question would work for me, but when I click the button you highlighted, it just reverts the view back to an axial slice, rather than the oblique one. For me, it acts as a “undo reformat” button.

Is there another way?

Below is an image of the oblique plane. I’m using a sample data set from Slicer rather than my actual data but it is the same part of the body.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/d/5df93036dd639001c4ab9c4cb44036e796905279.jpeg)

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