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Updated: Apr 20, 2026
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Simultaneous imaging of radiation-induced cerebral microbleeds, arteries and veins, using a multiple gradient echo
Wei Bian1,2, Suchandrima Banerjee3, Douglas A C Kelly4
1The UC Berkeley-UCSF Graduate Program in Bioengineering, University of California San Francisco, San Francisco, California, USA.
Background:
The purpose of this study was to implement and evaluate the utility of a multi-echo sequence at 7 Tesla (T) for simultaneous time-of-flight (TOF) MR-angiography (MRA) and susceptibility-weighted imaging (SWI) of radiation-induced cerebral microbleeds (CMBs), intracranial arteries, and veins.
Methods:
A four-echo gradient-echo sequence was implemented on a 7T scanner. The first echo was used to create TOF-MRA images, while the remaining echoes were combined to visualize CMBs and veins on SWI images. The sequence was evaluated on eight brain tumor patients with known radiation-induced CMBs. Single-echo images were also acquired to visually and quantitatively compare the contrast-to-noise ratio (CNR) of small- and intermediate-vessels between acquisitions. The number of CMBs detected with each acquisition was also quantified. Statistical significance was determined using a Wilcoxon signed-rank test.
Results:
Compared with the single-echo sequences, the CNR of small and intermediate arteries increased 7.6% (P < 0.03) and 9.5% (P = 0.06), respectively, while the CNR of small and intermediate veins were not statistically different between sequences (P = 0.95 and P = 0.46, respectively). However, these differences were not discernible by visual inspection. Also the multi-echo sequence detected 18.3% more CMBs (P < 0.008) due to higher slice resolution.
Conclusion:
The proposed 7T multi-echo sequence depicts arteries, veins, and CMBs on a single image to facilitate quantitative evaluation of radiation-induced vascular injury.
Insights
A new 7 Tesla multi-echo MRI sequence simultaneously visualizes arteries, veins, and radiation-induced cerebral microbleeds (CMBs). This advanced imaging technique improves detection of CMBs by 18.3% compared to standard methods.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Neuroimaging
- Radiology
Background:
- Radiation therapy can induce cerebral microbleeds (CMBs) and affect intracranial vasculature.
- Accurate visualization of CMBs, arteries, and veins is crucial for evaluating radiation-induced vascular injury.
- Existing MRI techniques may have limitations in simultaneously imaging these structures.
Purpose of the Study:
- To implement and evaluate a novel multi-echo sequence at 7 Tesla (T).
- To assess its utility for simultaneous time-of-flight MR-angiography (TOF-MRA) and susceptibility-weighted imaging (SWI).
- To visualize radiation-induced CMBs, intracranial arteries, and veins in a single acquisition.
Main Methods:
- A four-echo gradient-echo sequence was developed and implemented on a 7T MRI scanner.
- The first echo generated TOF-MRA images; subsequent echoes were combined for SWI.
- The sequence was tested on eight brain tumor patients, with comparisons to single-echo acquisitions for vessel contrast-to-noise ratio (CNR) and CMB detection.
Main Results:
- The multi-echo sequence demonstrated a statistically significant increase in CNR for small (7.6%) and intermediate (9.5%) arteries compared to single-echo sequences.
- No significant difference in CNR was observed for small or intermediate veins between the sequences.
- The multi-echo sequence detected 18.3% more CMBs than single-echo sequences, attributed to higher slice resolution.
Conclusions:
- The proposed 7T multi-echo sequence effectively visualizes arteries, veins, and CMBs simultaneously.
- This technique facilitates quantitative evaluation of radiation-induced vascular injury.
- The improved CMB detection highlights the potential of this sequence for clinical neuro-oncology applications.
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