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Validating a robust double-quantum-filtered1H MRS lactate measurement method in high-grade brain tumours
- Source :
- NMR in Biomedicine. 29:1420-1426
- Publication Year :
- 2016
- Publisher :
- Wiley, 2016.
-
Abstract
- 1H MRS measurements of lactate are often confounded by overlapping lipid signals. Double-quantum (DQ) filtering eliminates lipid signals and permits single-shot measurements, which avoid subtraction artefacts in moving tissues. This study evaluated a single-voxel-localized DQ filtering method qualitatively and quantitatively for measuring lactate concentrations in the presence of lipid, using high-grade brain tumours in which the results could be compared with standard acquisition as a reference. Paired standard acquisition and DQ-filtered 1H MR spectra were acquired at 3T from patients receiving treatment for glioblastoma, using fLASER (localization by adiabatic selective refocusing using frequency offset corrected inversion pulses) single-voxel localization. Data were acquired from 2 × 2 × 2 cm3 voxels, with a repetition time of 1 s and 128 averages (standard acquisition) or 256 averages (DQ-filtered acquisition), requiring 2.15 and 4.3 min respectively. Of 37 evaluated data pairs, 20 cases (54%) had measureable lactate (fitted Cramer–Rao lower bounds ≤ 20%) in either the DQ-filtered or the standard acquisition spectra. The measured DQ-filtered lactate signal was consistently downfield of lipid (1.33 ± 0.03 ppm vs 1.22 ± 0.08 ppm; p = 0.002), showing that it was not caused by lipid breakthrough, and that it matched the lactate signal seen in standard measurements (1.36 ± 0.02 ppm). In the absence of lipid, similar lactate concentrations were measured by the two methods (mean ratio DQ filtered/standard acquisition = 1.10 ± 0.21). In 7/20 cases with measurable lactate, signal was not measureable in the standard acquisition owing to lipid overlap but was quantified in the DQ-filtered acquisition. Conversely, lactate was undetected in seven DQ-filtered acquisitions but visible using the standard acquisition. In conclusion, the DQ filtering method has proven robust in eliminating lipid and permits uncontaminated measurement of lactate. This is important validation prior to use in tissues outside the brain, which contain large amounts of lipid and which are often susceptible to motion.
- Subjects :
- Single voxel
Chemistry
Subtraction
Lactate measurement
computer.software_genre
medicine.disease
030218 nuclear medicine & medical imaging
03 medical and health sciences
0302 clinical medicine
Nuclear magnetic resonance
Repetition Time
Voxel
Evaluated data
medicine
Molecular Medicine
Radiology, Nuclear Medicine and imaging
Double quantum
computer
030217 neurology & neurosurgery
Spectroscopy
Glioblastoma
Subjects
Details
- ISSN :
- 09523480
- Volume :
- 29
- Database :
- OpenAIRE
- Journal :
- NMR in Biomedicine
- Accession number :
- edsair.doi...........5b88cd7af80b081ad20f09af268e6b2e
- Full Text :
- https://doi.org/10.1002/nbm.3587