Quantification of multiple sclerosis lesion volumes in 1.5 and 0.5 T anisotropically filtered and unfiltered MR exams

Joseph Ross Mitchell, Stephen J. Karlik, Donald H. Lee, Michael Eliasziw, George P. Rice, Aaron Fenster

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Recently, guidelines for the use of MRI in the monitoring of MS have recommended the use of imaging systems with mid-field (0.5-1.0 T) or high- field (greater than 1.0 T) strengths. Higher field strengths provide many advantages, including increased signal-to-noise ratios (SNR). SNR also may be increased by post-processing algorithms that reduce noise. In this paper we evaluate the impact on operator variability of (a) lesion quantification in high-field (1.5 T) versus mid-field (0.5 T) exams; and (b) an anisotropic diffusion filter algorithm that reduces image noise without blurring or moving object boundaries. Inter- and intra-operator reliability and variability were studied using repeated quantification of lesions in 1.5 and 0.5 T filtered and unfiltered MR exams of a MS patient. Results indicate that inter-operator variability in 1.5 T unfiltered exams was 0.34 cm 3 and was significantly larger than that in 1.5 T filtered (0.27 cm 3), 0.5 T unfiltered (0.26 cm 3), and 0.5 T filtered (0.24 cm 3) exams. Similarly, intra-operator variability in 1.5 T unfiltered exams was 0.23 cm 3 and was significantly larger than that in 1.5 T filtered (0.19 cm 3), 0.5 T unfiltered (0.19 cm 3), and 0.5 T filtered (0.18 cm 3) exams. In addition, the minimum significant change between two successive measurements of lesion volume by the same operator, was 0.64 cm 3 in 1.5 T unfiltered exams, but 0.53 cm 3 or less in other exams. For two different operators making successive measurements, the minimum significant change was 0.94 cm 3 in 1.5 T unfiltered exams, but only 0.75 cm 3 or less in other exams. Finally, the number of lesions to be monitored for an average change in volume at a given power and significance level was greater by 30%-60% for quantification in 1.5 T unfiltered exams. These results suggest that inter- and intra-operator variability are reduced by anisotropic filtering, and by quantification in 0.5 T exams. Reduced operator variabilities may result from higher detail signal-to-noise ratios (dSNRs) in 0.5 T and filtered exams.

Original languageEnglish (US)
Pages (from-to)115-126
Number of pages12
JournalMedical Physics
Volume23
Issue number1
DOIs
StatePublished - Jan 1996
Externally publishedYes

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Signal-To-Noise Ratio
Multiple Sclerosis
Noise
Guidelines

ASJC Scopus subject areas

  • Biophysics

Cite this

Mitchell, J. R., Karlik, S. J., Lee, D. H., Eliasziw, M., Rice, G. P., & Fenster, A. (1996). Quantification of multiple sclerosis lesion volumes in 1.5 and 0.5 T anisotropically filtered and unfiltered MR exams. Medical Physics, 23(1), 115-126. https://doi.org/10.1118/1.597689

Quantification of multiple sclerosis lesion volumes in 1.5 and 0.5 T anisotropically filtered and unfiltered MR exams. / Mitchell, Joseph Ross; Karlik, Stephen J.; Lee, Donald H.; Eliasziw, Michael; Rice, George P.; Fenster, Aaron.

In: Medical Physics, Vol. 23, No. 1, 01.1996, p. 115-126.

Research output: Contribution to journalArticle

Mitchell, JR, Karlik, SJ, Lee, DH, Eliasziw, M, Rice, GP & Fenster, A 1996, 'Quantification of multiple sclerosis lesion volumes in 1.5 and 0.5 T anisotropically filtered and unfiltered MR exams', Medical Physics, vol. 23, no. 1, pp. 115-126. https://doi.org/10.1118/1.597689
Mitchell, Joseph Ross ; Karlik, Stephen J. ; Lee, Donald H. ; Eliasziw, Michael ; Rice, George P. ; Fenster, Aaron. / Quantification of multiple sclerosis lesion volumes in 1.5 and 0.5 T anisotropically filtered and unfiltered MR exams. In: Medical Physics. 1996 ; Vol. 23, No. 1. pp. 115-126.
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