Original article
Clinical applications of quantitative T2 determination: A complementary MRI tool for routine diagnosis of suspected myelination disorders

https://doi.org/10.1016/j.ejpn.2007.08.012Get rights and content

Abstract

Background and aims

Though magnetic resonance imaging (MRI) plays an important role in studying pathological changes in central nervous system, a quantitative measure of contrast variance on MRI, allowing the detection of subtle signal variances in pathological processes, is not readily available for routine imaging. We report on the first experiences with evaluation of routine T2 relaxation time measurement as a diagnostic tool in routine imaging of suspected myelination disorders.

Methods

Twenty patients suffering from defined or suspected myelination disorders were examined by MRI. T2 relaxation time maps of the brain were derived from a triple spin echo sequence. T2 values were measured for each patient by regions of interest (ROI) analysis. As references age-dependent T2 prediction values in normal maturating brains were calculated by using a biexponentional function reported earlier. Deviations from these prediction values were used as an assisting tool both for detection of pathology and for monitoring of changes over time. These quantitative results were compared to conventional visual inspections by two independent neuroradiologists.

Results

In 18 patients with single diagnostic MRI, the T2 measurements were more graduated or definite in 9/18 cases, confirmatory in 9/18 cases. In two patients with MRI follow up, the dynamic clinical course of the disease had no correlate in visual inspection of the images but was associated with the quantitative T2 values.

Conclusions

Quantitative T2 measurement is a promising tool for routine imaging as a complementary method in detecting and monitoring of suspected myelination disorders.

Introduction

Magnetic resonance imaging (MRI) plays an important role in studying pathological changes in central nervous system (CNS), especially in cases with disturbed myelination in maturating brains.1 The involvement and morphological changes of different brain structures are usually identified by visual inspection based on contrast variances shown by MRI. Many efforts were made in order to improve the sensitivity of MRI: contrast differences among brain tissues were improved by using different MRI technical parameters, including repetition time (TR) and echo time (TE) as well as sequence design for patients at different ages, e.g. neonates, infants or adults.2, 3 With visual inspection it is sometimes difficult to get an objective judgment about the myelination, in cases where the signal variances in physiological/pathological processes are subtle. Several scoring methods were proposed to quantify brain lesions based on the morphological inspection.4, 5, 6 Attention has also been paid to use different physical parameters to study brain maturation with MRI quantitatively, such as the relaxation times T1 and T2, magnetization transfer.7, 8, 9, 10, 11 New imaging techniques such as the diffusion-tensor imaging (DTI), which provides information about the degree of directedness in nerve fiber orientation and the structure of normal and pathological conditions, has been used to study the white matter (WM) of neonates.12 However, a quantitative measure of contrast variance on MRI, which moderates the influences of imaging parameters, window settings or the experience of the neuroradiologist carrying out the examination, is not readily available for routine imaging. Such a method would be very helpful to find subtle signal variances in pathological processes. The purpose of this paper is to report on our initial experiences with the application of quantitative T2 relaxation time measurements in routine imaging both for initial diagnosis of patients with suspected myelination disorders and monitoring of the disease over time, with emphasis to the feasibility in clinical routine and the diagnostic value in comparison with visual image inspection.

Section snippets

Subjects

Twenty consecutive patients suffering from defined (i.e. with known etiology) or suspected myelination disorders who were examined by MRI as a part of a routine diagnostic imaging procedure were enrolled in our study. Patients with brain tumor, vascular malformation or other structural defects were excluded. Eighteen of the patients (patients 1–18, numbered according to the age in Table 1) had a single MRI during their primary diagnostic workup. The other two patients (patients 19 and 20, Table

Results

Both conventional MR imaging findings and quantitative T2 measurements of the patients, briefly summarized in Table 1, Table 2, are described in the following, where only the T2 values obtained from the right brain hemisphere are presented and discussed since the measured T2 values showed no difference between the brain hemispheres (p<0.05).

Discussion

It has been shown that T2 in WM has two distinct components: a long T2 component (>70 ms at 1.5 T) being attributed to axonal and extracellular water and a short T component (20 ms at 1.5 T) being attributed to myelin water.16 On the other hand, Baratti et al. proved that the long component of T2 provide well information on brain maturation.17 Because our T2 relaxation times were calculated from echoes acquired at relatively long echo times, the measured T2 corresponds to the long T2 component of

Conclusion

We believe that despite theoretical shortcomings in T2 quantification, the method secures a benefit for routine purposes with limited extra time. This preliminary study indicates that quantitative T2 measurement is a promising tool for routine imaging as a complementary MRI method requiring limited extra effort in suspected myelination disorders, especially in very young children and patients in early disease stages. A prospective multicenter study is desirable to acquire more data in patients

Acknowledgment

This study was financially supported by the German Federal Ministry of Education and Research (BMBF), grant number 01GM0309.

References (17)

  • J. Ono et al.

    Evaluation of myelination by means of the T2 value on magnetic resonance imaging

    Brain Dev

    (1993)
  • A.J. Barkovich et al.

    Magnetic resonance imaging of normal and abnormal brain development

    Top Magn Reson Imaging

    (1993)
  • J. Dobbing et al.

    Quantitative growth and development of human brain

    Arch Dis Child

    (1973)
  • R.A. Jones et al.

    MRI of the neonatal brain: optimization of spin-echo parameters

    AJR Am J Roentgenol

    (2004)
  • D.J. Loes et al.

    Analysis of MRI patterns aids prediction of progression in X-linked adrenoleukodystrophy

    Neurology

    (2003)
  • C. Christophe et al.

    Value of MR imaging of the brain in children with hypoxic coma

    AJNR Am J Neuroradiol

    (2002)
  • O. Baenziger et al.

    Early pattern recognition in severe perinatal asphyxia: a prospective MRI study

    Neuroradiology

    (1993)
  • T. Autti et al.

    MRI of the normal brain from early childhood to middle age. II. Age dependence of signal intensity changes on T2-weighted images

    Neuroradiology

    (1994)
There are more references available in the full text version of this article.

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