Evaluation of the ERETIC method as an improved quantitative reference for 1H HR-MAS spectroscopy of prostate tissue.
The Electronic REference To access In vivo Concentrations (ERETIC) method was applied to (1)H HR-MAS spectroscopy. The accuracy, precision, and stability of ERETIC as a quantitative reference were evaluated in solution and human prostate tissue samples. For comparison, the reliability of 3-(trimethylsilyl)propionic-2,2,3,3-d(4) acid (TSP) as a quantitation reference was also evaluated. The ERETIC and TSP peak areas were found to be stable in solution over the short-term and long-term, with long-term relative standard deviations (RSDs) of 4.10% and 2.60%, respectively. Quantification of TSP in solution using the ERETIC peak as a reference and a calibrated, rotor-dependent conversion factor yielded results with a precision < or =2.9% and an accuracy error < or =4.2% when compared with the expected values. The ERETIC peak area reproducibility was superior to TSP's reproducibility, corrected for mass, in both prostate surgical and biopsy samples (4.53% vs. 21.2% and 3.34% vs. 31.8%, respectively). Furthermore, the tissue TSP peaks exhibited only 27.5% of the expected area, which would cause an overestimation of metabolite concentrations if used as a reference. The improved quantification accuracy and precision provided by ERETIC may enable the detection of smaller metabolic differences that may exist between individual tissue samples and disease states.
Albers
Mark J
MJ
Department of Bioengineering, University of California Berkeley, USA.
Butler
Thomas N
TN
Rahwa
Iman
I
Bao
Nguyen
N
Keshari
Kayvan R
KR
Swanson
Mark G
MG
Kurhanewicz
John
J
D000465:Algorithms; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards*; D008297:Male; D011467:Prostate / Q000378:metabolism*; D011522:Protons; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States
D011522:Protons