Clarification on Segment Statistics: Surface Area vs. Cross-Sectional Area (CSA) for Muscle Analysis

[mikebind (Mike Bindschadler)]

You are correct that Segment Statistics returns the 3D surface area of the generated mesh, the sum of the areas of all the triangles which make up the surface. To your second question, no, you can’t derive cross sectional areas by dividing the total surface area by a slice thickness. Such a calculation would give you an average volume per slice, but would not tell you about the CSA. To get a series of CSA values, you should cut across the muscle perpendicular to the axis you want to measure relative to (presumably the long axis of the muscle or perhaps a centerline of the muscle), and measure the enclosed area. This discussion will likely be helpful for you: Extracting muscle cross-sectional area and its centroid locatation from MRI/CT scans