Browsing by Subject "TOF"

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    Cerebrovascular modelling for the management of aneurysm embolization using an intrasaccular flow diverter made by 3D printing
    (Termedia Publishing House Ltd., 2022-10-15) Keles, Ayse; Oto, Cagdas; Algın, Oktay
    Purpose: Using 3-dimensional (3D) printers, the creation of patient-specific models is possible before and after a therapeutic intervention. There are many articles about replicas for training and simulation of aneurysm clipping. However, no paper has focused on 3D replicas obtained from 3-tesla 3D time of flight (3D-TOF) MR angiography for intrasaccular flow diverter (WEB device) embolization of the cerebral aneurysms. In this paper, we aimed to investigate the feasibility of 3D printing models obtained from 3-tesla 3D-TOF data in the management and training of WEB-assisted embolization procedures. Case presentation: We presented a longitudinal case report with several 3D-TOF MRA prints over time. Three-tesla 3D-TOF data were converted into STL and G-code files using an open-source (3D-Slicer) program. We built patient-specific realistic 3D models of a patient with a middle cerebral artery trifurcation aneurysm, which were able to demonstrate the entire WEB device treatment procedure in the pre-intervention and post-intervention periods. The aneurysmatic segment was well displayed on the STL files and the 3D replicas. They allowed visualization of the aneurysmatic segment and changes within a 6-year follow-up period. We successfully showed the possibility of fast, cheap, and easy production of replicas for demonstration of the aneurysm, the parent vessels, and post-intervention changes in a simple way using an affordable 3D printer. Conclusions: 3D printing is useful for training the endovascular team and the patients, understanding the aneurysm/ parent vessels, and choosing the optimal embolization technique/device. 3D printing will potentially lead to greater interventionalist confidence, decreased radiation dose, and improvements in patient safety. © Pol J Radiol 2022.
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    A comparison between the CS-TOF and the CTA/DSA for WEB device management
    (Sage Publications, 2021-05-06) Algin, Oktay; Yuce, G.; Koc, U.; Ayberk, G.
    Purpose There is no study on the role of three-dimensional compressed sensing time of flight MR angiography (3D-CS-TOF) in the management of the WEB device. We evaluated the efficacy of 3-tesla 3D-CS-TOF for the management and follow-up of the WEB device implantations. Materials and methods Seventy-three aneurysms of 69 patients treated with the WEB device were retrospectively examined. Morphological parameters and embolization results of the aneurysms were assessed and compared on 3D-CS-TOF, CTA, and DSA images. Results Occluded, neck remnant, and recurrent aneurysms were observed in 61 (83.6%), 7 (9.6%), and 5 (6.8%) aneurysms, respectively. Inter- and intra-reader agreement values related to aneurysm size measurements were perfect. Aneurysms size, age, and proximal vessel tortuosity were negatively correlated with the visibility of the aneurysms and parent vessels on 3D-CS-TOF images (p = 0.043; p = 0.032; p < 0.001, respectively). Subarachnoid hemorrhage and age are associated with 3D-CS-TOF artifacts (p = 0.031; p = 0.005, respectively). 3D-CS-TOF findings are in perfect agreement with DSA or CT angiography (CTA) results (p < 0.001). Conclusion According to our results, 3D-CS-TOF can be an easy, fast, and reliable alternative for the management or follow-up of WEB assisted embolization.
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    Joint partial fourier and compressed sensing reconstruction for accelerated time-of-flight MR angiography
    (IEEE, 2018) Kılıç, Toygan; Çukur, Tolga; Algin, Oktay; Sarıtaş, Emine Ülkü
    Time-of-flight (TOF) magnetic resonance (MR) angiography is a popular tool for non-contrast-enhanced angiographic imaging of intracranial vasculature. However, strategies that lead to enhancement of inflow effects come at the expense of prolonged scan times. This study proposes a combination of two dimensional (2D) acceleration in the phase-encode dimensions via compressed sensing (CS) and one dimensional (1D) partial Fourier (PF) data acquisition in the readout dimension to reduce echo time. An improved projections-onto-convex-sets (POCS) reconstruction framework is utilized, which decomposes the problem into 1D PF projections along the readout dimension, and 2D CS projections along the phase-encode dimensions. This framework enables scan-efficient TOF MR angiography imaging to help maintain high vessel-background contrast.