Fast chemical shift mapping with multiecho balanced SSFP.
OBJECTIVE
A method is proposed that provides spectroscopic images with high spatial resolution and moderate spectral resolution at very short total data acquisition times.


METHODS
Balanced steady-state free precession (bSSFP, TrueFISP, FIESTA, b-FFE) is combined with a multiecho readout gradient and frequency-sensitive reconstruction such as Fourier reconstruction known from echo-planar spectroscopic imaging (EPSI) or matrix inversion. Balanced SSFP imaging requires short repetition times to minimize banding artefacts, thereby restricting the achievable frequency resolution.


RESULTS
Two-dimensional (2D) high-resolution spectroscopic images were produced of three 1H resonances (water, acetone and fat) on phantoms and water/fat separation in vivo within 1-2 s. Additionally, fast 31P spectroscopic images were acquired from a phantom consisting of two resonances within 195 ms.


CONCLUSIONS
Frequency-sensitive reconstruction of multiecho bSSFP data can provide spectroscopic images with high spatial and temporal resolution while the frequency resolution is moderate at around 100 Hz. The method can also separate more than three resonances, allowing for hetero-nuclei metabolite mapping, for example 13C and 31P.
Leupold
Jochen
J
Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Hugstetter Strasse 55, 79106, Freiburg, Germany. jochen.leupold@uniklinik-freiburg.de
Wieben
Oliver
O
Månsson
Sven
S
Speck
Oliver
O
Scheffler
Klaus
K
Petersson
J Stefan
JS
Hennig
Jürgen
J
D002250:Carbon Radioisotopes / Q000737:chemistry; D017352:Echo-Planar Imaging; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D010761:Phosphorus Radioisotopes / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods*; D013696:Temperature; D013817:Thermography; D013997:Time Factors
D002250:Carbon Radioisotopes; D010761:Phosphorus Radioisotopes