Quantitative mapping of total choline in healthy human breast using proton echo planar spectroscopic imaging (PEPSI) at 3 Tesla.
OBJECTIVE
To quantitatively measure tCho levels in healthy breasts using Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI).


METHODS
The two-dimensional mapping of tCho at 3 Tesla across an entire breast slice using PEPSI and a hybrid spectral quantification method based on LCModel fitting and integration of tCho using the fitted spectrum were developed. This method was validated in 19 healthy females and compared with single voxel spectroscopy (SVS) and with PRESS prelocalized conventional Magnetic Resonance Spectroscopic Imaging (MRSI) using identical voxel size (8 cc) and similar scan times (∼7 min).


RESULTS
A tCho peak with a signal to noise ratio larger than 2 was detected in 10 subjects using both PEPSI and SVS. The average tCho concentration in these subjects was 0.45 ± 0.2 mmol/kg using PEPSI and 0.48 ± 0.3 mmol/kg using SVS. Comparable results were obtained in two subjects using conventional MRSI. High lipid content in the spectra of nine tCho negative subjects was associated with spectral line broadening of more than 26 Hz, which made tCho detection impossible. Conventional MRSI with PRESS prelocalization in glandular tissue in two of these subjects yielded tCho concentrations comparable to PEPSI.


CONCLUSIONS
The detection sensitivity of PEPSI is comparable to SVS and conventional PRESS-MRSI. PEPSI can be potentially used in the evaluation of tCho in breast cancer. A tCho threshold concentration value of ∼0.7 mmol/kg might be used to differentiate between cancerous and healthy (or benign) breast tissues based on this work and previous studies.
Department of Neurology and UNM Cancer Center, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA. chenggang.zhao@gmail.com
Chenguang
C
Zhao
Patrick J
PJ
Bolan
Melanie
M
Royce
Navneeth
N
Lakkadi
Steven
S
Eberhardt
Laurel
L
Sillerud
Sang-Joon
SJ
Lee
Stefan
S
Posse
D000328:Adult; D000465:Algorithms; D001940:Breast / Q000737:chemistry*; D002794:Choline / Q000032:analysis*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
D011522:Protons; D002794:Choline