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Published on: November 20, 2015
Time-of-Flight Intracranial MRA at 3 T versus 5 T versus 7 T: Visualization of Distal Small Cerebral Arteries
Zhang Shi1, Xueying Zhao1, Shuo Zhu1
1From the Departments of Radiology (Z.S., S.Z., X.M., X.Y., C.C., S.R., J.L., M.Z.) and Neurology (H.W.), Zhongshan Hospital, Fudan University, No. 180 Fenglin Rd, Xuhui District, Shanghai 200032, China; Shanghai Institute of Medical Imaging, Shanghai, China (Z.S., S.Z., Y.Z., X.Y., C.C., S.R., J.L., M.Z.); Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China (X.Z., B.W., B.Z., H.W.); Central Research Institute, United Imaging Healthcare, Shanghai, China (Y.Z., Y.D.); Shanghai United Imaging Healthcare, Shanghai, China (S.H.).
Abstract:
Background Three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) at 7 T has been reported to have high image quality for visualizing small perforating vessels. However, B1 inhomogeneity and more physiologic considerations limit its applications. Angiography at 5 T may provide another choice for intracranial vascular imaging. Purpose To evaluate the image quality and cerebrovascular visualization of 5-T 3D TOF MRA for visualizing intracranial small branch arteries. Materials and Methods Participants (healthy volunteers or participants with a history of ischemic stroke undergoing intracranial CT angiography or MRA for identifying steno-occlusive disease) were prospectively included from September 2021 to November 2021. Each participant underwent 3-T, 5-T, and 7-T 3D TOF MRA with use of customized MR protocols within 48 hours. Radiologist scoring from 0 (invisible) to 3 (excellent) and quantitative assessment were obtained to evaluate the image quality. The Friedman test was used for comparison of characteristics derived from 3 T, 5 T, and 7 T. Results A total of 12 participants (mean age ± SD, 38 years ± 9; nine men) were included. Visualizations of the distal arteries and small vessels at 5-T TOF MRA were significantly higher than those at 3 T (median score: 3.0 vs 2.0, all P < .001 for distal segments and lenticulostriate artery; median score: 2.0 vs 0, P < .001 for pontine artery). The total length of small vessel branches detected at 5 T was larger than that at 3 T (5.1 m ± 0.7 vs 1.9 m ± 0.4; P < .001). However, there was no evidence of a significant difference compared with 7 T in either the depiction of distal segments and small vessel branches (average median score, 2.5; all P > .05) or the quantitative measurements (total length, 5.6 m ± 0.5; P = .41). Conclusion Three-dimensional time-of-flight MR angiography at 5 T presented the capability to provide superior visualization of distal large arteries and small vessel branches (in terms of subjective and quantitative assessment) to 3 T and had image quality similar to 7 T. © RSNA, 2022 Online supplemental material is available for this article. An earlier incorrect version appeared online. This article was corrected on September 14, 2022.
Insights
Five-tesla (5T) 3D time-of-flight MR angiography (MRA) offers superior visualization of intracranial small arteries compared to 3T MRA. This advanced technique provides image quality comparable to 7T MRA, enhancing diagnostic capabilities for cerebrovascular imaging.
Area of Science:
- Radiology and Imaging Science
- Neuroimaging
- Magnetic Resonance Imaging (MRI)
Background:
- High-resolution imaging of small perforating vessels is crucial for diagnosing cerebrovascular diseases.
- Seven-tesla (7T) 3D time-of-flight MR angiography (MRA) shows promise but faces limitations due to B1 inhomogeneity.
- Five-tesla (5T) MRA presents a potential alternative for intracranial vascular imaging.
Purpose of the Study:
- To evaluate the image quality of 5T 3D TOF MRA for visualizing intracranial small branch arteries.
- To compare the cerebrovascular visualization capabilities of 5T MRA against 3T and 7T MRA.
Main Methods:
- Prospective enrollment of 12 participants (healthy volunteers or stroke patients) between September and November 2021.
- Acquisition of 3T, 5T, and 7T 3D TOF MRA using customized protocols within 48 hours.
- Radiologist scoring (0-3) and quantitative assessments to evaluate image quality and vessel visualization.
Main Results:
- 5T MRA demonstrated significantly higher visualization scores for distal arteries and small vessels compared to 3T MRA (P < .001).
- The total length of detected small vessel branches was significantly greater with 5T MRA than 3T MRA (5.1m vs 1.9m; P < .001).
- Image quality and quantitative measurements for 5T MRA were comparable to 7T MRA (P > .05).
Conclusions:
- 5T 3D TOF MRA provides superior visualization of distal intracranial arteries and small vessel branches compared to 3T MRA.
- The image quality achieved with 5T MRA is similar to that of 7T MRA, offering a viable option for detailed cerebrovascular imaging.
- 5T MRA enhances the assessment of small vessel disease and steno-occlusive conditions.
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