High-resolution 3D MR spectroscopic imaging of the prostate at 3 T with the MLEV-PRESS sequence.
A 3 T MLEV-point-resolved spectroscopy (PRESS) sequence employing optimized spectral-spatial and very selective outer-voxel suppression pulses was tested in 25 prostate cancer patients. At an echo time of 85 ms, the MLEV-PRESS sequence resulted in maximally upright inner resonances and minimal outer resonances of the citrate doublet of doublets. Magnetic resonance spectroscopic imaging (MRSI) exams performed at both 3 and 1.5 T for 10 patients demonstrated a 2.08+/-0.36-fold increase in signal-to-noise ratio (SNR) at 3 T as compared with 1.5 T for the center citrate resonances. This permitted the acquisition of MRSI data with a nominal spatial resolution of 0.16 cm3 at 3 T with similar SNR as the 0.34-cm3 data acquired at 1.5 T. Due to the twofold increase in spectral resolution at 3 T and the improved magnetic field homogeneity provided by susceptibility-matched endorectal coils, the choline resonance was better resolved from polyamine and creatine resonances as compared with 1.5 T spectra. In prostate cancer patients, the elevation of choline and the reduction of polyamines were more clearly observed at 3 T, as compared with 1.5 T MRSI. The increased SNR and corresponding spatial resolution obtainable at 3 T reduced partial volume effects and allowed improved detection of the presence and extent of abnormal metabolite levels in prostate cancer patients, as compared with 1.5 T MRSI.
Chen
Albert P
AP
Department of Radiology, University of California at San Francisco, San Francisco, CA 94143-2512, USA.
Cunningham
Charles H
CH
Kurhanewicz
John
J
Xu
Duan
D
Hurd
Ralph E
RE
Pauly
John M
JM
Carvajal
Lucas
L
Karpodinis
Kostas
K
Vigneron
Daniel B
DB
D000368:Aged; D000465:Algorithms; D002794:Choline / Q000378:metabolism; D002951:Citrates / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000378:metabolism*
D002951:Citrates; D002794:Choline