title: Reliability and exactness of MRI-based volumetry: a phantom study.
abstract: This study investigated the influence of 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 region-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 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.
authors.affiliation: Department of Neuroradiology, University of Tübingen, Germany.
authors.forename: A R
authors.initials: AR
authors.lastname: Luft
authors.forename: M
authors.initials: M
authors.lastname: Skalej
authors.forename: D
authors.initials: D
authors.lastname: Welte
authors.forename: R
authors.initials: R
authors.lastname: Kolb
authors.forename: U
authors.initials: U
authors.lastname: Klose
mesh_terms: D000465:Algorithms; D005583:Fourier Analysis; D005782:Gels; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009532:Nickel; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012685:Sepharose; D012984:Software
chemical_list: D005782:Gels; D009532:Nickel; D012685:Sepharose