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Continuous prospectively navigated multi-echo GRE for improved BOLD imaging of the kidneys
Glen Robert Morrell1, Eun-Kee Jeong1, Xianfeng Shi2
1Utah Center for Advanced Imaging Research, University of Utah Radiology Department, Salt Lake City, Utah, USA.
NMR in Biomedicine
|February 28, 2019
Summary
A new free-breathing renal BOLD imaging method improves kidney oxygen level assessment. This technique offers higher signal-to-noise ratio and resolution compared to breath-hold methods, aiding in noninvasive renal disease monitoring.
Area of Science:
- Medical Imaging
- Renal Physiology
- Diagnostic Techniques
Background:
- Renal blood oxygenation level dependent (BOLD) imaging, specifically T2* mapping, is a promising noninvasive tool for assessing renal oxygenation and monitoring kidney disease progression.
- Conventional breath-hold BOLD (BH-BOLD) techniques are limited by low resolution and signal-to-noise ratio (SNR) due to short imaging windows.
- Improved methods are needed to overcome these limitations for more accurate and reliable renal BOLD imaging.
Purpose of the Study:
- To develop and evaluate an improved free-breathing renal BOLD (FB-BOLD) imaging method.
- To compare the performance of the new FB-BOLD technique against conventional BH-BOLD in terms of image quality and T2* fitting accuracy.
- To assess the potential of FB-BOLD for enhanced noninvasive renal disease monitoring.
Main Methods:
- A novel multi-echo gradient-recalled echo (GRE) sequence was developed, incorporating continuous prospective respiratory navigation and real-time feedback for free-breathing acquisition.
- The sequence maintained a constant repetition time (TR) to allow for high-resolution and high-SNR renal BOLD imaging during free breathing.
- The FB-BOLD sequence was tested in 10 healthy volunteers and compared to conventional BH-BOLD, analyzing SNR and T2* fitting residual error.
Main Results:
- The FB-BOLD sequence successfully produced motion-free T2* maps of the kidneys.
- FB-BOLD imaging achieved a 1.9 times higher SNR compared to BH-BOLD images.
- Residual error in T2* fitting was 30% lower in the right kidney with FB-BOLD but 80% higher in the left kidney, potentially due to navigator placement.
Conclusions:
- The developed free-breathing, prospectively navigated renal BOLD sequence enables high-resolution, high-SNR renal T2* mapping.
- This method offers a flexible trade-off between scan time, resolution, and SNR, surpassing the limitations of conventional breath-hold techniques.
- FB-BOLD represents a significant advancement for noninvasive renal oxygenation assessment and disease monitoring.
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