I would like to obtain a segment of adipose tissue whose radial distance from the blood vessel wall is equal to the diameter of the blood vessel, and this segment can change along with the variation of the blood vessel diameter. Then, I need to measure its CT value. So, what should I do?
Currently, I have used the “paint” tool to outline the target blood vessel (assuming the diameter of the blood vessel is 9 mm). Then, I applied the “hollow” function to expand it by 1 mm and 9 mm respectively. After that, I used “logical operators” to subtract (subtracting 1 mm is to avoid the artifacts caused by contrast agents). In the remaining range of 8 mm, I set the threshold for adipose tissue, and finally used the “segment statistics” function to calculate the average CT value.
However, there are still two problems:
After applying the “hollow” function, it doesn’t simply expand along the planar edge of the selected blood vessel. Instead, it seems to expand in all directions with this layer as the center. If I only want to expand on the plane of the selected blood vessel section, what should I do? (Currently, the solution I adopted is to manually erase the parts outside the scope.)
If a segment of blood vessel with a certain length is selected and the thickness of the entire blood vessel varies, and I want the expansion distance to change with the diameter of the blood vessel, what should I do?
What you describe sounds reasonable if you are willing to write a somewhat detailed script, which would be worth it if you want to do this semi-automatically on a lot of data. If you want to do this manually I’d suggest just doing the calculation at a few representative spots along the vessel and paint the desired segments manually with the size and shape you need.
2.In the cross section analysis, may I ask what are the different meanings and results of selecting Centerline Source between Centerline model and Centerline curve, and what is the difference between the Diameter (MIS) and (CE) tables obtained after applying the table, and which one is more accurate？
MIS and CE diameter are quite different ways to extract the radius.
MIS uses minimal inscribed sphere method to extract radius ( In my experience, this method struggles with very tortouse geometries)
CE diameter uses the cross section diameter estimated using the perpendicular planes from the nodes (and some more, due to internal interpolations the code made…) of your centerline. Again, in my experience, this usually struggles in bifurcations and zones where your centerline is not providing great perpendicular planes.
Since @seraphina has already excluded the external carotid artery, the measurements are reliable. Nevertheless, extreme tortuosity is a problematic case, but this is not the case here.
Thank you very much for your answer. Can I understand that CE diameter is better compared to others.Because I excluded the external carotid artery.I can use the measured CE diameter for further research.
‘Better’ is not the right term. Your research goals determine which one suits best. The CE diameter conveys a functional meaning. The MIS diameter carries a geometric information.
Thank you very much for your answer, but I don’t quite understand the actual nature. My research goal is to obtain tissues whose radial distance from the blood vessel wall is equal to the diameter of the blood vessel. My current ability is not able to change each layer accordingly, so I intend to choose the minimum value measured. May I ask which one should I choose just to get the most true blood vessel diameter?
