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Object strength - an accurate measure for small objects that is insensitive to partial volume effects

journal contribution
posted on 2023-06-07, 13:49 authored by P. S. Tofts, N. C. Silver, G. J. Barker, A. Gass
There are currently four problems in characterising small nonuniform lesions or other objects in Magnetic Resonance images where partial volume effects are significant. Object size is over- or under-estimated; boundaries are often not reproducible; mean object value cannot be measured; and fuzzy borders cannot be accommodated. A new measure, Object Strength, is proposed. This is the sum of all abnormal intensities, above a uniform background value. For a uniform object, this is simply the product of the increase in intensity and the size of the object. Biologically, this could be at least as relevant as existing measures of size or mean intensity. We hypothesise that Object Strength will perform better than traditional area measurements in characterising small objects. In a pilot study, the reproducibility of object strength measurements was investigated using MR images of small multiple sclerosis (MS) lesions. In addition, accuracy was investigated using artificial lesions of known volume (0.3-6.2 ml) and realistic appearance. Reproducibility approached that of area measurements (in 33/90 lesion reports the difference between repeats was less than for area measurements). Total lesion volume was accurate to 0.2%. In conclusion, Object Strength has potential for improved characterisation of small lesions and objects in imaging and possibly spectroscopy.

History

Publication status

  • Published

Journal

Magnetic Resonance Materials in Physics, Biology and Medicine

ISSN

0968-5243

Publisher

Springer Verlag

Issue

3

Volume

18

Page range

162-169

Department affiliated with

  • BSMS Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2007-02-28

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