Quantitative T2 measurement of a single voxel with arbitrary shape using pinwheel excitation and CPMG acquisition.

Qin Q, Gore JC, de Graaf RA, Does MD
MAGMA. 2007 20 (5-6): 233-40

PMID: 17999101 · PMCID: PMC2634838 · DOI:10.1007/s10334-007-0088-9

OBJECTIVE - The aim of this study is to present a new approach for making quantitative single-voxel T (2) measurements from an arbitrarily shaped region of interest (ROI), where the advantage of the signal-to-noise ratio (SNR) per unit time of the single-voxel approach over conventional imaging approach can be achieved.

MATERIALS AND METHODS - Two-dimensional (2D) spatially selective radiofrequency (RF) pulses are proposed in this work for T (2) measurements based on using interleaved spiral trajectories in excitation k-space (pinwheel excitation pulses), combined with a summed Carr-Purcell Meiboom-Gill (CPMG) echo acquisition. The technique is described and compared to standard multi-echo imaging methods, on a two-compartment water phantom and an excised brain tissue.

RESULTS - The studies show good agreement between imaging and our method. The measured improvement factors of SNR per unit time of our single-voxel approach over imaging approach are close to the predicted values.

CONCLUSION - Measuring T (2) relaxation times from a selected ROI of arbitrary shape using a single-voxel rather than an imaging approach can increase the SNR per unit time, which is critical for dynamic T (2) or multi-component T (2) measurements.

MeSH Terms (9)

Animals Biomedical Engineering Brain Echo-Planar Imaging Humans Magnetic Resonance Imaging Phantoms, Imaging Radio Waves Saimiri

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