Calculating potential error in sodium MRI with respect to the analysis of small objects.
Magn Reson Med
; 79(6): 2968-2977, 2018 06.
Article
in En
| MEDLINE
| ID: mdl-29023969
ABSTRACT
PURPOSE:
To facilitate correct interpretation of sodium MRI measurements, calculation of error with respect to rapid signal decay is introduced and combined with that of spatially correlated noise to assess volume-of-interest (VOI) 23 Na signal measurement inaccuracies, particularly for small objects.METHODS:
Noise and signal decay-related error calculations were verified using twisted projection imaging and a specially designed phantom with different sized spheres of constant elevated sodium concentration. As a demonstration, lesion signal measurement variation (5 multiple sclerosis participants) was compared with that predicted from calculation.RESULTS:
Both theory and phantom experiment showed that VOI signal measurement in a large 10-mL, 314-voxel sphere was 20% less than expected on account of point-spread-function smearing when the VOI was drawn to include the full sphere. Volume-of-interest contraction reduced this error but increased noise-related error. Errors were even greater for smaller spheres (40-60% less than expected for a 0.35-mL, 11-voxel sphere). Image-intensity VOI measurements varied and increased with multiple sclerosis lesion size in a manner similar to that predicted from theory. Correlation suggests large underestimation of 23 Na signal in small lesions.CONCLUSIONS:
Acquisition-specific measurement error calculation aids 23 Na MRI data analysis and highlights the limitations of current low-resolution methodologies. Magn Reson Med 792968-2977, 2018. © 2017 International Society for Magnetic Resonance in Medicine.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sodium
/
Signal Processing, Computer-Assisted
/
Magnetic Resonance Imaging
/
Multiple Sclerosis
Type of study:
Prognostic_studies
Limits:
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Magn Reson Med
Journal subject:
DIAGNOSTICO POR IMAGEM
Year:
2018
Document type:
Article
Affiliation country:
Canadá