Neurovascular stent artifacts in 3D‐TOF and 3D‐PCMRI: Influence of stent design on flow measurement

Bouillot, Pierre; Brina, Olivier; Delattre, Bénédicte; Ouared, Rafik; Pellaton, Alain; Yılmaz, Hasan; Machi, Paolo; Lövblad, Karl-Olof; Farhat, Mohamed; Pereira, Vítor Mendes; Vargas, María Isabel

doi:10.1002/mrm.27352

Cited by 19 publications

(25 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We excluded patients with aneurysms presenting more than half of their volume with unreliable velocities with Vel an , 7.7 cm/s before FDS implantation. This threshold corresponds to the measurement error previously identified and reported in Pereira et al 22 and Bouillot et al 23 Flow Rates (QICA). As described in Bouillot et al, 24 measurement planes, each separated by 2 mm, were automatically placed orthogonal to the vessel center line within a user-selected distance corresponding to the C2-3 segment ( Fig 1C.1).…”

Section: Proportional Velocity-reduction Ratio Calculationsupporting

confidence: 58%

“…This study was made possible due to prior investigations on intracranial stent-related artifacts. 23 In particular, we showed that these artifacts were mainly related to the shielding effect and were therefore restricted to the stent lumen. Furthermore, the following recent technical developments 24 were assembled in a postprocessing pipeline to obtain consistent and reliable PVRR and Vel an assessment from 4D-PCMR data: 1) the combination of 4D-PCMR data with 3DRA geometry for a precise delineation of the circulating domain; 2) the partial volume correction allowing unbiased ICA mean flow-rate quantification; and 3) the semiautomatic aneurysm extraction, thus ensuring a systematic and user-independent selection of the volume of interest and the consistent inclusion of the relevant aneurysm inflow velocities close to the neck.…”

Section: Pcmr Measurements and Flow Diversionmentioning

confidence: 77%

“…Our main limitation, with a potential impact on the results, was the choice of the poststent VENC, which led us to decrease this parameter from 80 cm/s (the first 17 patients) to 40 cm/s (in the remaining 6 patients) to capture the low velocities more accurately at the expense of aliasing artifacts. Furthermore, to rely on the aneurysmal velocities presented in this study, we used the cutoff published in Pereira et al 22 and Bouillot et al 23 to exclude patients with .50% of their prestent velocities below this value, assuming that poststent measurements would be severely biased. For some patients, the proportion of aneurysm volume below this threshold could have been larger than 50% after stent placement, thus reflecting very low velocities or nearly stagnant flows.…”

Section: Limitationsmentioning

confidence: 99%

“…However, we have shown that these metallic artifacts are limited to the lumen of the stent without extension to the aneurysm bulge, which guarantees the accuracy of the velocities measured in the aneurysm volume. 23 On the basis of these results, we aimed to measure pre-and post-FDS velocity fields with 4D-PCMR in a prospective patient cohort and to correlate hemodynamic changes with aneurysm occlusion outcomes at 6 and 12 months.…”

mentioning

confidence: 99%

See 3 more Smart Citations

How Flow Reduction Influences the Intracranial Aneurysm Occlusion: A Prospective 4D Phase-Contrast MRI Study

Brina¹,

Bouillot

Reymond³

et al. 2019

AJNR Am J Neuroradiol

View full text Add to dashboard Cite

BACKGROUND AND PURPOSE: Flow-diverter stents are widely used for the treatment of wide-neck intracranial aneurysms. Various parameters may influence intracranial aneurysm thrombosis, including the flow reduction induced by flow-diverter stent implantation, which is assumed to play a leading role. However, its actual impact remains unclear due to the lack of detailed intra-aneurysmal flow measurements. This study aimed to clarify this relationship by quantitatively measuring the intra-aneurysmal flow using 4D phase-contrast MR imaging. MATERIALS AND METHODS:We acquired prospective pre-and post-stent implantation 4D phase-contrast MR imaging data of a consecutive series of 23 patients treated with flow-diverter stents. Velocity field data were combined with the intraprocedural 3D angiogram vessel geometries for precise intracranial aneurysm extraction and partial volume correction. Intra-aneurysmal hemodynamic modifications were compared with occlusion outcomes at 6 and 12 months. RESULTS:The averaged velocities at systole were lower after flow-diverter stent implantation for all patients and ranged from 21.7 6 7.1 cm/s before to 7.2 6 2.9 cm/s after stent placement. The velocity reduction was more important for the group of patients with aneurysm thrombosis at 6 months (68.8%) and decreased gradually from 66.2% to 55% for 12-month thrombosis and no thrombosis, respectively (P = .08). CONCLUSIONS:We propose an innovative approach to measure intracranial flow changes after flow-diverter stent implantation. We identified a trend between flow reduction and thrombosis outcome that brings a new insight into current understanding of the flow-diversion treatment response.ABBREVIATIONS: CFD 4 computational fluid dynamics; 3DRA 4 3D rotational angiography; FDS 4 flow-diverter stent; IA 4 intracranial aneurysm;PCMR 4 phase-contrast MRI; PVRR 4 proportional velocity-reduction ratio; Q ICA 4 ICA systolic flow rates ratio; Q ICA 4 ICA mean flow rates; Vel an 4 intraaneurysmal velocity; VENC 4 velocity encoding

show abstract

Section: Proportional Velocity-reduction Ratio Calculationsupporting

confidence: 58%

Section: Pcmr Measurements and Flow Diversionmentioning

confidence: 77%

Section: Limitationsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

How Flow Reduction Influences the Intracranial Aneurysm Occlusion: A Prospective 4D Phase-Contrast MRI Study

Brina¹,

Bouillot

Reymond³

et al. 2019

AJNR Am J Neuroradiol

View full text Add to dashboard Cite

show abstract

“…Earlier reports show that the number of wires in braided stents and stent design can affect the shielding effectiveness. 13 Other reports show that the shielding effects varied with stent materials, geometry, and orientation. Kalamazoo, MI, USA]) for the purpose of investigation of the relationship between RF-shielding effect and material and design.…”

Section: Discussionmentioning

confidence: 98%

Investigating Signal Loss due to a Carotid Artery Stent in 3D-TOF-MRA

et al. 2021

View full text Add to dashboard Cite

In this study, we investigated the factors of signal loss out because of the presence of a stent and optimized imaging parameters for improvement in depiction ability. Methods: We investigated the relationship between the stent type and magnetic susceptibility effect by measuring the signal value between the inside and outside of the stent with different Bw and TE for two different kinds of stents respectively. Similarly, flip angles were changed for two different kinds of stents respectively to the signal intensity between the inside and the outside of the stent was measured, in which examine the relationship between the stent type and the Ernst angles in RF-shielding effect. The conventional imaging parameters and the optimum imaging parameters for each stent obtained from the result of the phantom experiment were examined. Optimized 3D time-of-flight MR angiography (3D-TOF-MRA) was performed and compared with conventional 3D-TOF-MRA and computed tomography angiography (CTA). Results: The influence of the magnetic susceptibility effect is small in the central part of Carotid Wallstent and in PRECISE, and large in the Carotid Wallstent at the both ends. The influence of RF-shielding effect was large at PRECISE, where the Ernst angle was greatly shifted while the effect is no longer influenced at Carotid Wallstent. Both Carotid Wallstent and PRECISE made imaging capability improved by optimizing the imaging parameters. Conclusion: During clinical imaging of patients post-carotid artery stenting (CAS) using our protocol, the ability to visualize blood vessels was improved. Thus, we demonstrated that the ability of 3D-TOF-MRA post-CAS was improved via optimizing imaging parameters.

show abstract

3D‐printed, patient‐specific intracranial aneurysm models: From clinical data to flow experiments with endovascular devices

et al. 2021

View full text Add to dashboard Cite

Flow models of intracranial aneurysms (IAs) can be used to test new and existing endovascular treatments with flow modulation devices (FMDs). Additionally, 4D flow magnetic resonance imaging (MRI) offers the ability to measure hemodynamics. This way, the effect of FMDs can be determined noninvasively and compared to patient data. Here, we describe a cost-effective method for producing flow models to test the efficiency of FMDs with 4D flow MRI. Methods: The models were based on human radiological data (internal carotid and basilar arteries) and printed in 3D with stereolithography. The models were printed with three different printing layers (25, 50, and 100 µm thickness). To evaluate the models in vitro, 3D rotational angiography, time-offlight MRI, and 4D flow MRI were employed. The flow and geometry of one model were compared with in vivo data. Two FMDs (FMD1 and FMD2) were deployed into two different IA models, and the effect on the flow was estimated by 4D flow MRI. Results: Models printed with different layer thicknesses exhibited similar flow and little geometric variation. The mean spatial difference between the vessel geometry measured in vivo and in vitro was 0.7 AE 1.1 mm. The main flow features, such as vortices in the IAs, were reproduced. The velocities in the aneurysms were similar in vivo and in vitro (mean velocity magnitude: 5.4 AE 7.6 and 7.7 AE 8.6 cm/s, maximum velocity magnitude: 72.5 and 55.1 cm/s). By deploying FMDs, the mean velocity was reduced in the IAs (from 8.3 AE 10 to 4.3 AE 9.32 cm/s for FMD1 and 9.9 AE 12.1 to 2.1 AE 5.6 cm/s for FMD2). Conclusions: The presented method allows to produce neurovascular models in approx. 15 to 30 h. The resulting models were found to be geometrically accurate, reproducing the main flow patterns, and suitable for implanting FMDs as well as 4D flow MRI.

show abstract

Neurovascular stent artifacts in 3D‐TOF and 3D‐PCMRI: Influence of stent design on flow measurement

Abstract: The present results motivate the conception of low inductance or nonconductive stent design. Furthermore, the feasibility of near-stent 3D-PCMRI measurements opens the door to clinical applications like the post-treatment follow-up of stenoses or intracranial aneurysms.

Cited by 19 publications

References 47 publications

How Flow Reduction Influences the Intracranial Aneurysm Occlusion: A Prospective 4D Phase-Contrast MRI Study

How Flow Reduction Influences the Intracranial Aneurysm Occlusion: A Prospective 4D Phase-Contrast MRI Study

Investigating Signal Loss due to a Carotid Artery Stent in 3D-TOF-MRA

3D‐printed, patient‐specific intracranial aneurysm models: From clinical data to flow experiments with endovascular devices

Contact Info

Product

Resources

About