A USPIO doped gel phantom for R2* relaxometry

Brown, Gregory C., Cowin, Gary J. and Galloway, Graham J. (2016) A USPIO doped gel phantom for R2* relaxometry. Magnetic Resonance Materials in Physics, Biology and Medicine, 30 1: 1-13. doi:10.1007/s10334-016-0576-x


Author Brown, Gregory C.
Cowin, Gary J.
Galloway, Graham J.
Title A USPIO doped gel phantom for R2* relaxometry
Formatted title
A USPIO doped gel phantom for R2* relaxometry
Journal name Magnetic Resonance Materials in Physics, Biology and Medicine   Check publisher's open access policy
ISSN 0968-5243
1352-8661
Publication date 2016-07-19
Sub-type Article (original research)
DOI 10.1007/s10334-016-0576-x
Open Access Status Not yet assessed
Volume 30
Issue 1
Start page 1
End page 13
Total pages 13
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Subject 3614 Radiological and Ultrasound Technology
1304 Biophysics
2741 Radiology Nuclear Medicine and imaging
Abstract Objective: This work describes a phantom containing regions of controlled R2* (1/T2*) values to provide a stable reference object for testing implementations of R2* relaxometry commonly used for liver and heart iron assessments. Materials and methods: A carrageenan-strengthened gadolinium DTPA doped agarose gel was used to enclose nine gels additionally doped with ultra-small superparamagnetic iron oxide. R2* values were determined at 1.5 T using multi-echo GRE sequences and exponential regression of pixel values from a region of interest against echo time using non-linear regression algorithms. We measured R2*, R2 and R1 values and the inter-scan and inter-operator reproducibility. Results: The phantom reliably demonstrated R2* values in seven steps between 22.4 s (SE 1.98) and 441.9 s (SE 6.76), with an R2* relaxivity (r2*) of 792 (SE 5.6) mM s. The doped gels displayed a concentration-dependent R2ʹ component of R2* phantom, indicating superparamagnetic enhancement effects. We observed no significant change in relaxivity (r2*) over 12 months, and estimate a useful life of 3 years. Detailed descriptions of the production process and calculators are been provided as Online Resources. Conclusion: The phantom provides a durable test object with controlled R2* relaxation behaviour, useful for a range of R2* relaxometry reference work.
Formatted abstract
Objective: This work describes a phantom containing regions of controlled R2* (1/T2*) values to provide a stable reference object for testing implementations of R2* relaxometry commonly used for liver and heart iron assessments.

Materials and methods: A carrageenan-strengthened gadolinium DTPA doped agarose gel was used to enclose nine gels additionally doped with ultra-small superparamagnetic iron oxide. R2* values were determined at 1.5 T using multi-echo GRE sequences and exponential regression of pixel values from a region of interest against echo time using non-linear regression algorithms. We measured R2*, R2 and R1 values and the inter-scan and inter-operator reproducibility.

Results: The phantom reliably demonstrated R2* values in seven steps between 22.4 s−1 (SE 1.98) and 441.9 s−1 (SE 6.76), with an R2* relaxivity (r2*) of 792 (SE 5.6) mM−1 s−1. The doped gels displayed a concentration-dependent R2ʹ component of R2* phantom, indicating superparamagnetic enhancement effects. We observed no significant change in relaxivity (r2*) over 12 months, and estimate a useful life of 3 years. Detailed descriptions of the production process and calculators are been provided as Online Resources.

Conclusion:
The phantom provides a durable test object with controlled R2* relaxation behaviour, useful for a range of R2* relaxometry reference work.
Keyword Calibration
MRI
Quantitative evaluation
Phantom imaging
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Centre for Advanced Imaging Publications
 
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Created: Tue, 06 Sep 2016, 02:15:08 EST by Gregory Brown on behalf of Queensland Brain Institute