Determination of Tissue Volumes

Abstract

Purpose: To evaluate MR imaging for tissue volume measurements.

Material and Methods: Imaging was done with a spoiled gradient echo technique using the human lower leg as a simple model and CT as the reference technique. Areas of adipose tissue, muscle plus skin and bone tissue were evaluated in 5 volunteers using signal intervals (MR) and attenuation intervals (CT) defined by histograms. Volumes were determined from 7 images (MR-7, CT-7), from 70 contiguous images (MR-70), and also from a commercially-available 3D program based on a seeding technique applied according to the operators' judgment (MR-op).

Results: the sum of bone tissue, muscle plus skin and adipose tissue were similar for CT and MR. Compared to CT-7, MR-7 and MR-70 overestimated adipose tissue (0–8%) and muscle plus skin (11–15%), while bone tissue was underestimated (61–78%). Determinations based on the contiguous images or the 7 images were similar (standard error 2–5%). MR-op resulted in pronounced underestimation of muscle plus skin and bone tissue and a minor underestimation of adipose tissue.

Conclusion: Valid determinations of adipose tissue volume are possible with MR but further technical development is required for other tissue volumes. the technique applied according to the operators' judgement, as used for 3D surface rendition, is unreliable for tissue volume determinations.