Ellen Ackerstaff1, Nirilanto Ramamonjisoa1, H. Carl LeKaye1, Kristen L. Zakian1, Ekaterina Moroz1, Inna S. Serganova1, Ronald G. Blasberg1, and Jason A. Koutcher1
Aggressive, treatment-resistant tumors have been associated with high
tumor lactate. For the absolute quantification of in vivo tumor lactate by the substitution method, it is essential
to correct for differences between reference phantom and in vivo lactate T1 and T2 relaxation times (LacT1/T2).
The LacT1/T2 acquisition requires specialized MR
sequences and is hampered in vivo by
long acquisition times and low lactate SNR. Here, we measure LacT1/T2
for various orthotopic breast and subcutaneous prostate cancer models in
immune-competent and immune-compromised hosts. Our results indicate that using
an average LacT1/T2 correction factor introduces less
than 20% error in the lactate quantification.