Quantitative ¹H magnetization transfer imaging in vivo

Abstract

A major factor contributing to proton (1H) spin-lattice relaxation in biological tissues is believed to be magnetization transfer between 1H in free bulk water and 1H restricted motion associated with macromolecules. We have shown recently that saturation transfer is an effective approach for studying this magnetization transfer process. Herein the determination of magnetization transfer rates in biological tissues is further analyzed by considering the time and power dependencies of saturation transfer. Following these analyses, quantitative magnetization transfer rate constant image maps were collected from the kidney in vivo. These rate constant images may prove useful in quantitative tissue characterization and in the determination of tissue-specific 1H relaxation mechanisms.

Magnetization transfer MRS

“…Subsequently bulk water transfers magnetization via intermolecular cross relaxation to creatine. 11,12,62 The involvement of mobile bulk water becomes obvious from MT via low energy saturation of mobile bulk water, 45,48 cf. Fig.…”

Understanding and optimizing the amplitude modulated control for multiple‐slice continuous arterial spin labeling

“…The optimum value of B 1 for the AM pulse when f ϭ 250 Hz in the animal model is approximately 300 Hz in the absence of spin relaxation and 220 Hz with spin relaxation. The peak amplitude of the AM pulse must be ͌2 times the B 1 applied for the label to produce equal MTC in label and control images (26). Therefore, based on a peak amplitude of 220 Hz for the AM control, the labeling pulse should have an amplitude of 156 Hz.…”

Evaluation of bioreactor-cultivated bone by magnetic resonance microscopy and FTIR microspectroscopy

“…MRM can also be used to evaluate the collagen content of tissues because collagen gives rise to a significant magnetization transfer (MT) effect (23,24). The MT effect is the result of crossrelaxation between mobile water protons and the less mobile hydroxyl groups on the collagen molecules (25,26). In fact, calibration curves have been derived for this MRM parameter and the collagen content of articular cartilage (27), engineered cartilage (28), and collagen gels (27,29,30).…”