Pitfalls in Lactate Measurements at 3T

Single-voxel spectra acquired at 3T from the brain of a patient with a grade III glioma by using PRESS localization. B, TE = 144 ms. C, TE = 288 ms. Cr indicates creatine.

Multivoxel spectra acquired 1 hour apart at 1.5T and 3T from the same region in the brain of a patient with MELAS, by using standard PRESS localization with TE = 144 ms and TE = 288 ms. An inverted lactate doublet is clearly visible at 1.5T, but not at 3T (arrows). Upright lactate peaks at TE = 288 are seen equally well at both field strengths (arrows).

Proton spectra acquired from a standard brain metabolite phantom containing 5 mmol/L of lactate. The measurements were performed on 3 3T MR imaging scanners from 3 different vendors (Philips Medical Systems, GE Healthcare, and Siemens Medical Solutions). Single-voxel MR spectra (VOI size = 2 × 2 × 2 cm³, PRESS localization) were acquired from the same volume once with TE = 144 ms and once with TE = 288 ms. Radio-frequency pulse bandwidths for the selective refocusing pulses vary between vendors in the range of 874–2300 Hz.

Spectra from an MRSI imaging dataset acquired at 3T from a phantom containing 10 mmol/L of NAA and 20 mmol/L of lactate without PRESS localization. A, TE = 144 ms, with refocusing pulse gradient. B, TE = 144 ms, without refocusing pulse gradient. C, TE = 288 ms, with refocusing pulse gradient. D, TE = 288 ms, without refocusing pulse gradient.