Optimization of fast spiral chemical shift imaging using least squares reconstruction: application for hyperpolarized (13)C metabolic imaging.
Magn Reson Med
; 58(2): 245-52, 2007 Aug.
Article
em En
| MEDLINE
| ID: mdl-17654596
ABSTRACT
A least-squares-based optimization and reconstruction algorithm has been developed for rapid metabolic imaging in the context of hyperpolarized (13)C. The algorithm uses a priori knowledge of resonance frequencies, J-coupling constants, and T(2)* values to enable acquisition of high-quality metabolic images with imaging times of approximately 100 ms for an 8-cm field of view (FOV) and 0.5 cm isotropic resolution. A root-mean-square error (rMSE) analysis is introduced to optimize metabolic image quality by appropriate choice of pulse sequence parameters, echo times, and signal model. By performing the reconstruction in k-space, the algorithm also allows the inclusion of the effect of chemical shift evolution during the readout period. Single-interleaf multiecho spiral chemical shift imaging (spCSI) is analyzed in detail as an illustrative example for the use of the new reconstruction and optimization algorithm. Simulation of the in vivo spectrum following the bolus injection of hyperpolarized (13)C(1) pyruvate shows that single-interleaf spiral spectroscopic imaging can achieve image quality in 100 ms, comparable to the performance of a 13-s phase-encoded chemical shift imaging (FIDCSI) experiment. Single-interleaf spCSI was also tested at a 3-T MR scanner using a phantom containing approximately 0.5-M solutions of alanine, lactate, and a pyruvate-pyruvate hydrate C(1)-C(2) ester at thermal equilibrium polarization, all enriched to 99% (13)C in the C(1) carbonyl positions. Upon reconstruction using the k-space-based least-squares technique, metabolite ratios obtained using the spCSI method were comparable to those obtained using a reference FIDCSI acquisition.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Algoritmos
/
Imageamento por Ressonância Magnética
Idioma:
En
Revista:
Magn Reson Med
Assunto da revista:
DIAGNOSTICO POR IMAGEM
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos