A Model for the Dynamics of Spins 3/2 in Biological Media: Signal Loss during Radiofrequency Excitation in Triple-Quantum-Filtered Sodium MRI
✍ Scribed by Ileana Hancu; Johan R.C. van der Maarel; Fernando E. Boada
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 169 KB
- Volume
- 147
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
We have derived the differential equations that describe the dynamics of spin-3/2 nuclei in the presence of radiofrequency (RF) fields and both static and fluctuating quadrupolar interactions. The formalism presented was used to predict the sodium triplequantum-filtered (TQ-filtered) signal loss in a whole-body scanner, where the widths of the hard 90°RF pulses are on the same order of magnitude as the transverse relaxation times. A small piece of bovine nasal cartilage, known for exhibiting residual quadrupolar splittings, was used to test the theory. The sample was modeled as consisting of small domains, each characterized by a static quadrupolar interaction constant, with an overall Gaussian distribution across the sample. An increase of about 15% in the TQ-filtered signal strength, as the 90°RF pulse width was decreased from 500 to 100 s, was predicted and demonstrated experimentally for this particular sample.