Leiden University Student Repository

Vlaar, Annelies (2018)

Contribution of inflammation and fat infiltration to T2

Bachelor thesis | Natuurkunde (BSc)

The MRI time constant T2 of water is an indication of inflammation in muscles but is difficult to identify when fat is infiltrated in the muscle. A model that takes both the T2 of fat and the T2 of water into account can be used to determine the T2 of water when the T2 of fat is known. The T2 of fat in affected muscles is equal to subcutaneous fat. To determine the T2 of subcutaneous fat the Extended Phase Graph model is used which calculates the contribution of spins to the MRI signal taking the effects of relaxation, dephasing and radiofrequency pulses into account. It is therefore able to keep track of the contribution of stimulated echoes to the MRI signal. The observed T2 fat values show differences in the order of magnitude of 10 ms in different parts of subcutaneous fat. T2 fat values determined by the presented EPG model are 50 to 80 ms higher than the actual values. Suggested improvements to the EPG model includes usages of a different shaped RF pulse and to take into...Show moreThe MRI time constant T2 of water is an indication of inflammation in muscles but is difficult to identify when fat is infiltrated in the muscle. A model that takes both the T2 of fat and the T2 of water into account can be used to determine the T2 of water when the T2 of fat is known. The T2 of fat in affected muscles is equal to subcutaneous fat. To determine the T2 of subcutaneous fat the Extended Phase Graph model is used which calculates the contribution of spins to the MRI signal taking the effects of relaxation, dephasing and radiofrequency pulses into account. It is therefore able to keep track of the contribution of stimulated echoes to the MRI signal. The observed T2 fat values show differences in the order of magnitude of 10 ms in different parts of subcutaneous fat. T2 fat values determined by the presented EPG model are 50 to 80 ms higher than the actual values. Suggested improvements to the EPG model includes usages of a different shaped RF pulse and to take into account different gradient strengths, frequencies of spins and the chemical shift of water and fat.Show less

MRI

T2

inflammation

fat infiltration

Author

Vlaar, Annelies

Faculty

Faculty of Science

Supervisors

Beenakker, J.W.M.

ECTS Credits

3

Language

en