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T1 and T2 relaxation time estimates in the normal human brain
I Agartz1, J Sääf, L O Wahlund
1Department of Psychiatry, Karolinska Institute, St Göran's Hospital, Stockholm, Sweden.
Radiology
|November 1, 1991
Summary
This study estimated magnetic resonance (MR) relaxation times T1 and T2 in healthy adults. T1 values showed a unique age-related pattern, peaking in middle age, unaffected by sex or laterality.
Area of Science:
- Neuroimaging
- Biophysics
Background:
- Magnetic resonance (MR) imaging provides insights into tissue properties through relaxation time constants.
- Understanding age-related changes in brain tissue is crucial for interpreting neurological conditions.
Purpose of the Study:
- To estimate T1 and T2 relaxation times in specific brain regions of healthy adults across a wide age range.
- To investigate the influence of age, sex, and laterality on these relaxation times.
Main Methods:
- In vivo MR imaging was performed using 0.02-T and 0.8-MHz parameters.
- T1 values were derived from inversion-recovery sequences, and T2 values from spin-echo sequences.
- Polynomial regression analysis was used to model age-dependency.
Main Results:
- Distinct T1 values differentiated investigated brain regions (frontal/occipital white matter, caudate, thalamus).
- T1 relaxation times exhibited a cradle-shaped relationship with age, with minima around 40-45 years.
- While overall age-dependency was similar, sex-specific differences in T1 curves were observed.
Conclusions:
- MR relaxation times, particularly T1, can characterize brain regions and reveal age-related structural changes.
- The identified age-dependency of T1 relaxation times provides a normative reference for aging brains.
- Findings suggest potential sex-specific variations in brain aging processes detectable by MR.