T1 relaxography

T1 relaxography is a form of magnetic resonance imaging.

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Magnetic Imaging resonance uses the resonance of the protons to gerate images. Protons are exited by a radiofrequency pulse of an appropriate frequency and then emit energy in the form of radiofrequency (RF) signal as they return to their original state. The RF signal decays with an exponential curve characterized by a parameter T1 (see Relaxation (NMR)).

In conventional MRI the signal is sampled at only one time point (the echo time) after the RF pulse. T1 relaxography combines several acquisitions at different echo times and uses this information to calculate the parameter T1 at each voxel. This parameter can then be mapped throughout the brain. The value of T1 may have more information than is provided by the conventional scans. T1 is significantly different between grey matter and white matter allowing for easy automatic segmentation of images.

References

• Clare S, Jezzard P.: Rapid T(1) mapping using multislice echo planar imaging. Magn Reson Med 45:630-634, 2001. Available online at PubMed: [1]