Transcranial ultrasound localization microscopy in moyamoya patients using a clinical ultrasound system
Louise Denis1, Elena Meseguer2, Augustin Gaudemer2
1Sorbonne Université, CNRS, INSERM Laboratoire d'Imagerie Biomédicale, Paris, France.
Abstract:
Background: Deep brain structures are supplied by perforating arteries, which are too thin to be observed with non-invasive and widely available clinical imaging methods. In moyamoya disease, main arteries in the base of the brain progressively narrow, and perforating arteries grow densely and tortuously to compensate the lack of blood supply in deep brain structures. Purpose: The aim of this study is to evaluate the efficacy of transcranial ultrasound localization microscopy (ULM) in visualizing perforating arteries, utilizing a standard low-frame-rate ultrasound clinical scanner and contrast sequences commonly employed in hospital settings. Methods: This prospective single-center study included ischemic stroke patients not related to the study of perforating arteries, and moyamoya disease patients. Contrast-enhanced ultrasound sequences (CEUS) were performed by an experienced neurologist and the images acquired were used to perform post-processing ULM. ULM density maps were compared with conventional 3T TOF MRI and color Doppler imaging in both groups. Results: We included a group of 15 control patients and another group of 9 moyamoya patients between March 2023 and March 2024. The patients had an average age of 45 ± 14 years (65% male). Perforating arteries were captured on all subjects, with a mean diameter of 0.8 ± 0.3 mm in control patients, while it was not possible with TOF MRI or color Doppler (P < 0.05). Moreover, ULM enabled to highlight differences between healthy subjects and those with moyamoya disease through track mean distance (P = 0.05). Conclusions: Using a low-frame-rate ultrasound scanner, CEUS and accessible post-processing tools, we demonstrate that transcranial ULM can facilitate the visualization and characterization of perforating arteries, even in cases where they were previously undetectable using standard non-invasive imaging techniques. We speculate that with the advent of high-frame-rate 3D ULM, this technique may find widespread utility in hospitals.
Insights
Transcranial ultrasound localization microscopy (ULM) successfully visualizes tiny perforating arteries missed by standard MRI and Doppler. This advancement offers new diagnostic potential for conditions like moyamoya disease.
Area of Science:
- Neuroimaging
- Vascular Biology
- Medical Ultrasound
Background:
- Perforating arteries supplying deep brain structures are crucial but too small for conventional non-invasive imaging.
- Moyamoya disease involves progressive narrowing of major brain arteries, leading to compensatory, tortuous growth of perforating arteries.
- Existing imaging methods often fail to visualize these critical, small vessels.
Purpose of the Study:
- To assess the effectiveness of transcranial ultrasound localization microscopy (ULM) for visualizing perforating arteries.
- To utilize standard clinical ultrasound equipment and contrast sequences for this purpose.
- To compare ULM with established imaging techniques like MRI and Doppler.
Main Methods:
- Prospective single-center study involving ischemic stroke and moyamoya disease patients.
- Contrast-enhanced ultrasound (CEUS) performed by an experienced neurologist.
- Post-processing of CEUS images for ULM density map generation and comparison with 3T TOF MRI and color Doppler.
Main Results:
- Perforating arteries were visualized in all 24 subjects (15 controls, 9 moyamoya) using ULM.
- ULM detected mean perforating artery diameters (0.8 ± 0.3 mm) not achievable with TOF MRI or color Doppler (P < 0.05).
- ULM identified differences between healthy and moyamoya patients via track mean distance (P = 0.05).
Conclusions:
- Transcranial ULM, using low-frame-rate ultrasound and CEUS, effectively visualizes and characterizes previously undetectable perforating arteries.
- This technique offers a significant advancement over standard non-invasive imaging for evaluating deep brain vasculature.
- Future high-frame-rate 3D ULM holds promise for widespread clinical application in hospitals.
