Reliability and exactness of MRI-based volumetry: A phantom study

This study investigated the influence slice thickness, section orientation, contrast, shape, and sequence type on the exactness of MRI-based volumetry, Ni-doped agarose gel phantoms (4 to 46 ml) were scanned with a T1-weighted three-dimensional Fourier transform (FT) fast low-angle shot (FLASH) and a multiecho two-dimensional FT-Turbo spin-echo (SE) sequence, After segmentation with a three-dimensional legion-growing algorithm, the geometric volume was measured considering the partial volume effect, The variability coefficient (Pearson) was .7%, The volumetric error increased with slice thickness, depending on the size and form of the object, Cross sections resulted in smaller error than longitudinal sections (finger-shaped phantoms, nonisotropic image data), Three-dimensional FT was superior to two-dimensional FT imaging. Results of slice thickness and section orientation experiments can be explained by the partial volume effect Higher errors in two-dimensional FT imaging were caused by object movements between two interleaved acquisitions, The study shows a considerable influence of the imaging parameters on the exactness, which depends on size and form of the structure of interest.