In:
Investigative Radiology, Ovid Technologies (Wolters Kluwer Health), Vol. 54, No. 3 ( 2019-3), p. 169-176
Abstract:
The aim of this study was to examine the variation in signal intensity ratio (SIR) values in Eurospin gel phantoms and healthy volunteer (HV) brain images in response to different magnetic resonance imaging hardware and software settings. Materials and Methods Gel phantoms with T1 relaxation times similar to the dentate nucleus (DN), pons (P), globus palladus (GP), and thalamus (Th) were scanned using a T1-weighted 2-dimensional spin-echo sequence on 2 magnetic resonance imaging scanners (3 T and 1.5 T). Imaging was performed by sequentially altering selected magnetic resonance (MR) parameters relative to a default pulse sequence, and the protocol was implemented repeatedly over 3 months. The experiment was also repeated on a cohort of 15 young HVs. Calculations of DN/P and GP/Th SIR values were derived for the images of the gels (Gel DN/P and Gel GP/Th ) and the HVs (HV DN/P and HV GP/Th ). Results For the default sequence, the mean SIR values of Gel DN/P and Gel GP/Th varied by ±2.20% and ±0.75%, respectively, when measured over multiple imaging sessions (3 T). Within a single imaging session, these variations were smaller (±0.17% for Gel DN/P and ±0.15% for Gel GP/Th ). At 1.5 T, the equivalent SIR variations for Gel DN/P were ±1.41% (multiple sessions) and ±0.41% (single session), and that for Gel GP/Th were ±0.47% (multiple sessions) and ±0.33% (single session). Sequential changes to the MR sequence parameters resulted in gel SIR variations as follows: 14.07% ± 2.43% (with/without normalization filters), −7.80% ± 0.28% (different echo times, TE), and −5.06% ± 0.59% (selective activation of RF coil elements). The largest variations were noted when the gels were positioned below the scanner isocenter, where SIR measurements were different by 22%. For the HVs, the SIR values were found to be consistently within 0.64% (single session) for the default sequence. Sequential changes to the MR sequence parameters resulted in SIR variations of −24.47% ± 2.47% (with/without normalization filters), −15.32% ± 7.71% (different echo times, TE), and −2.90% ± 0.78% (selective activation of RF coil elements). Conclusions This study has demonstrated that SIR percentage changes from baseline of a similar magnitude to brain gadolinium contrast agent signal hyperintensities can be replicated in phantom models and HVs by altering common MR acquisition parameters and hardware.
Type of Medium:
Online Resource
ISSN:
1536-0210
,
0020-9996
DOI:
10.1097/RLI.0000000000000526
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2019
detail.hit.zdb_id:
2041543-6
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