MTR and T1 provide complementary information in MS NAWM,but not in lesions

Abstract

MTR and T1 relaxation times are abnormal in MS lesions and NAWM, and may reflect tissue damage such as demyelination and axonal loss. Their relationship and potential to provide complementary information in tissue characterisation is explored. The aim of this study was to document the relationship between magnetisation transfer ratio (MTR) and T1 relaxation time in Multiple Sclerosis (MS) lesions and normal appearing white matter (NAWM) in order to determine whether the combination provides a more comprehensive tissue characterisation than either parameter in isolation. Ten patients with relapsing remitting MS and 10 age matched healthy controls underwent imaging using a protocol which included the measurement of both MTR and T1 relaxation times. The MTR and T1 values were compared statistically using a commonly adopted correlation approach and a mixed-model regression approach. There was a strong correlation between MTR and T1 in MS lesions (r=0.74). The correlation was seen equally in T1 hypointense and isointense lesions. The relationship was much weaker in MS NAWM (r=0.24) and no correlation was found in control white matter (r=0.06). Mixed-model regression analysis confirmed that the relationship between T1 and MTR is strongly dependent upon tissue type (MS lesion, MS NAWM, or control white matter). The relationship between MTR and T1 relaxation time measurements varies markedly between pathological and normal tissue types. In MS, the complementary information obtained from MTR and T1 is most apparent in NAWM. The results emphasise the potential for combinations of MR parameters to improve tissue characterisation, which in turn should improve understanding of disease pathology and treatment monitoring.

Keywords

multiple sclerosis magnetisation transfer ratio T1 relaxation time normal appearing white matter

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References

Ormerod IEC et al. (1987) The role of NMR imaging in the assessment of multiple sclerosis and isolated neurological lesions. A quantitative study . Brain 110: 1579-1616 .

Loevner LA et al. (1995) Microscopic disease in normal appearing white matter on conventional images in patients with multiple sclerosis: assessment with magnetisation measurements . Radiology 196: 511-515 .

Gonzalez-Scarano F et al. (1987) Multiple sclerosis disease activity correlates with Gadolinium-enhanced magnetic resonance imaging . Ann Neurol 21: 300-306 .

Katz D et al. (1993) Correlation between magnetic resonance image findings and lesion development in chronic, active multiple sclerosis . Ann Neurol 34: 661-669

Gass A et al. (1994) Correlation of magnetization transfer ratio with clinical disability in multiple sclerosis . Ann Neurol 36: 62-67 .

Van Walderveen MAA et al. (1995) Correlating MRI and clinical disease; relevance of hypointense lesions on short-TR/short-TE (T1 weighted) spin echo images . Neurology 45: 1684-1690

van Waesberghe JHTM et al. (1998) MR outcomes in multiple sclerosis. Comparison of conventional parameters and MTR parameters in association with disability . Proc Int Soc Magn Reson 2: 1319-1319 .

McGowan JC et al. (1998) Magnetisation transfer imaging theory and application to multiple sclerosis . JNeurol Neurosurg Psychiatry 64 (Suppl): S66-S69 .

Hiehle JF et al. (1995) Magnetization transfer effects in MR detected multiple sclerosis lesions; comparison with gadolinium enhanced spin echo images and non enhanced T1 weighted images . Am Journal Neuroradiol 16: 69-77 .

10.

Kurtzke JF. (1983) Rating neurological impairment in multiple sclerosis; an expanded disability status scale; (EDSS) . Neurology 33: 1444-1452 .

11.

Barker GJ et al. (1996) An interleaved sequence for accurate and reproducible clinical measurement of magnetization transfer ratio . Magn Reson Imaging 14: 403-405 .

12.

Parker GJM et al. (1999) Accurate multislice T1 measurement in the presence of non ideal RF pulse profiles and RF field inhomogeneity . Proc Intl Soc Magn Reson Med 7: 2144-2144 .

13.

Symms MR et al. (1997) Improving spatial registration of multislice two dimensional MR images with a radio-graphical repositioning technique [Abstract.] Proc Int Soc Magn Reson Med 5: 689-689 .

14.

Plummer DL. (1992) Disp Image: a display and analysis tool for medical images . Revista Di Neuroradiologica 5: 489-495 .

15.

Filippi M et al. (1998) Effect of training and different measurement strategies on the reproducibility of brain MRI lesion load measurements in multiple sclerosis . Neurology 50: 238-244 .

16.

Van Waesberghe JHTM et al. (1997) Comparison of four potential parameters of tissue destruction in multiple sclerosis lesions . Magn Reson Imaging 15: 155-162 .

17.

Hand D et al. (1996) Practical longitudinal data analysis. Chapman and Hall, London .

18.

Sullivan L et al. (1999) Tutorial in biostatistics. An introduction to hierarchical linear modelling . Statist Med 18: 855-888 .

19.

SAS Institute Inc. SAS/STAT software: Changes and Enhancements through Release 6.11, SAS Institute Inc, Cary, NC, 1996.

20.

Silver NC et al. (1998) Serial magnetisation transfer imaging to characterise the early evolution of new MS lesions . Neurology 51: 1-7 .

21.

Allen IV et al. (1979) A histological, histochemical and biochemical study of the macroscopically normal white matter in multiple sclerosis . J Neurol Sci 41: 81-91 .

22.

Tourtellotte WW et al. (1968) Some spaces and barriers in post mortem multiple sclerosis. In Lajtha A , Ford DH (eds). Brain Barrier Systems. Progress in Brain Research, Vol. 29, Elsevier: Amsterdam , pp 493-525.