Aim: To evaluate whether 3-T four-dimensional (4D) arterial spin-labelling (ASL) -based magnetic resonance angiography (MRA) is useful for assessing the collateral circulation via the circle of Willis in patients with carotid artery steno-occlusive disease.
Materials And Methods: Institutional review board approval and prior written informed consent from all patients were obtained. The inclusion criteria were fulfilled by 13 patients with carotid artery steno-occlusive disease. All underwent 4D-ASL MRA at 3 T and digital subtraction angiography (DSA). The flow-sensitive alternating inversion recovery (FAIR) preparation scheme with look-locker sampling was used for spin labeling. At 300-ms intervals seven dynamic scans were obtained with a spatial resolution of 0.5×0.5×0.6 mm(3). The collateral flow via the circle of Willis was read on 4D-ASL MRA and DSA images by two sets of two independent readers each. κ statistics were used to assess interobserver and intermodality agreement.
Results: On DSA, collateral flow via the anterior communicating artery (AcomA) was observed in six patients, via the posterior communicating artery (PcomA) in four patients, and via both the AcomA and PcomA in three patients. With respect to the qualitative evaluation of 4D-ASL MRA images, interobserver agreement was excellent for all items (κ=1). 4D-ASL MRA and DSA consensus readings agreed on the type of collateral flow pattern in 10 of the 13 patients (77%). Intermodality agreement was good (κ=0.606; 95% confidence interval (CI): 0.215-0.997).
Conclusion: 3 T 4D-ASL MRA may be a useful tool for the evaluation of the collateral circulation in patients with carotid artery steno-occlusive disease.
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http://dx.doi.org/10.1016/j.crad.2015.05.002 | DOI Listing |
Cureus
May 2024
Department of Radiology, Juntendo University School of Medicine, Tokyo, JPN.
Objective and background This study aimed to develop a deep convolutional neural network (DCNN) model capable of generating synthetic 4D magnetic resonance angiography (MRA) from 3D time-of-flight (TOF) images, allowing estimation of temporal changes in arterial flow. TOF MRA provides static information about arterial structures through maximum intensity projection (MIP) processing, but it does not capture the dynamic information of contrast agent circulation, which is lost during MIP processing. Considering the principles of TOF, it is hypothesized that dynamic information about arterial blood flow is latent within TOF signals.
View Article and Find Full Text PDFMagn Reson Imaging
July 2024
Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai 200433, China; Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Beijing 200433, China. Electronic address:
Segmentation of cerebral vasculature on MR vascular images is of great significance for clinical application and research. However, the existing cerebrovascular segmentation approaches are limited due to insufficient image contrast and complicated algorithms. This study aims to explore the potential of the emerging four-dimensional arterial spin labeling magnetic resonance angiography (4D ASL-MRA) technique for fast and accurate cerebrovascular segmentation with a simple machine-learning approach.
View Article and Find Full Text PDFJ Magn Reson Imaging
October 2024
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Arterial spin labeling (ASL) is a noninvasive imaging technique that labels the proton spins in arterial blood and uses them as endogenous tracers. Brain perfusion imaging with ASL is becoming increasingly common in clinical practice, and clinical applications of ASL for intracranial magnetic resonance angiography (MRA) have also been demonstrated. Unlike computed tomography (CT) angiography and cerebral angiography, ASL-based MRA does not require contrast agents.
View Article and Find Full Text PDFObjective: Cerebrovascular diseases are one of the main global causes of death and disability in the adult population. The preferred imaging modality for the diagnostic routine is digital subtraction angiography, an invasive modality. Time-resolved three-dimensional arterial spin labeling magnetic resonance angiography (4D ASL MRA) is an alternative non-invasive modality, which captures morphological and blood flow data of the cerebrovascular system, with high spatial and temporal resolution.
View Article and Find Full Text PDFMed Image Anal
August 2019
Department of Radiology and Hotchkiss Brains Institute University of Calgary, Calgary, AB, Canada.
Four-dimensional arterial spin labeling magnetic resonance angiography (4D ASL MRA) is a non-invasive medical imaging modality that can be used for anatomical and hemodynamic analysis of the cerebrovascular system. However, it generates a considerable amount of data, which is tedious to analyze visually. As an alternative, medical image processing methods can be used to process the data and present measurements of the geometry and blood flow in the cerebrovascular system to the user, such as vessel radius, tortuosity, blood flow volume, and transit time.
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