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Schönfeld MH, Forkert ND, Fiehler J, Cho YD, Han MH, Kang HS, Peach TW, Byrne JV. Hemodynamic Differences Between Recurrent and Nonrecurrent Intracranial Aneurysms: Fluid Dynamics Simulations Based on MR Angiography. J Neuroimaging 2019; 29:447-453. [PMID: 30891876 DOI: 10.1111/jon.12612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Although the role of wall shear stress (WSS) in the initiation, growth, and rupture of intracranial aneurysms has been well studied, its influence on aneurysm recurrence after endovascular treatment requires further investigation. We aimed to compare WSS at necks of recurrent and nonrecurrent aneurysms. METHODS Nine recurrent coil-embolized aneurysms were identified and matched with nine nonrecurrent aneurysms. Patient-specific vessel geometries reconstructed from follow-up 3-D time-of-flight magnetic resonance angiography were analyzed using computational fluid dynamics (CFD) simulations. Absolute WSS and the percentage of abnormally low and high WSS at the aneurysm neck compared to the near artery were measured. RESULTS The median percentage of abnormal WSS at the aneurysm neck was 49.3% for recurrent and 34.7% for nonrecurrent aneurysms (P = .011). The area under the receiver-operating-characteristic curve for distinguishing these aneurysms according to the percentage of abnormal WSS was .86 (95% CI .62 to .98). The optimal cut-off value of 45.1% resulted in a sensitivity and a specificity of 88.89% (95% CI 51.8% to 99.7%). CONCLUSION Our findings indicate that necks of recurrent aneurysms are exposed to abnormal WSS to a larger extent. Abnormal WSS may serve as a metric to distinguish them from nonrecurrent aneurysms with CFD simulations a priori.
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Affiliation(s)
- Michael Hinrich Schönfeld
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nils Daniel Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Jens Fiehler
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Young Dae Cho
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Moon Hee Han
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hyun-Seung Kang
- Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Thomas William Peach
- Department of Mechanical Engineering, University College London, London, UK.,Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - James Vincent Byrne
- Oxford Neurovascular & Neuroradiology Research Unit, Oxford Radcliffe Hospital, Oxford, UK
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Ernst M, Kriston L, Groth M, Frölich AM, Fiehler J, Buhk JH. Factors Influencing Confidence in Diagnostic Ratings and Retreatment Recommendations in Coiled Aneurysms. AJNR Am J Neuroradiol 2018; 39:869-874. [PMID: 29567657 DOI: 10.3174/ajnr.a5581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 01/03/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Angiographic occlusion and retreatment of coiled aneurysms are commonly used as surrogate end points in clinical trials. We aimed to evaluate the influence of aneurysm, patient, and rater characteristics on the confidence of visual evaluation of aneurysm coiling and retreatment decisions. MATERIALS AND METHODS Twenty-six participants of the Advanced Course in Endovascular Interventional Neuroradiology of the European Society of Neuroradiology were asked to evaluate digital subtraction angiography examinations of patients who had undergone endovascular coiling, by determining the grade of aneurysm occlusion, the change between immediate postprocedural and follow-up angiograms, their level of confidence, the technical difficulty of retreatment, and the best therapeutic approach. The experience, knowledge, and skills of each participant were assessed. The influence of rater and case characteristics on indicated confidence in diagnostic ratings and retreatment recommendations was analyzed. RESULTS Interrater reliability was moderate regarding the assessment of aneurysm occlusion grade (intraclass correlation coefficient = 0.581) and substantial regarding change (intraclass correlation coefficient = 0.776). Overall confidence in the diagnostic rating was high (median, "very certain"). Confidence was statistically significantly higher in cases that were generally rated as "worse." The odds of recommending retreatment were significantly higher in cases that were generally rated with higher mean confidence. CONCLUSIONS Although overall confidence in the diagnostic rating was high, our study confirms the suboptimal interrater reliability of visual assessment of aneurysm occlusion as well as retreatment recommendations, rendering both questionable as primary outcome measures. Besides recurrence status, recommendation of retreatment is significantly influenced by patient age, aneurysm neck width, and characteristics of the therapist.
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Affiliation(s)
- M Ernst
- From the Department of Diagnostic and Interventional Neuroradiology (M.E., M.G., A.M.F., J.F., J.-H.B.), Center for Radiology and Endoscopy
| | - L Kriston
- Department of Medical Psychology (L.K.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Groth
- From the Department of Diagnostic and Interventional Neuroradiology (M.E., M.G., A.M.F., J.F., J.-H.B.), Center for Radiology and Endoscopy
| | - A M Frölich
- From the Department of Diagnostic and Interventional Neuroradiology (M.E., M.G., A.M.F., J.F., J.-H.B.), Center for Radiology and Endoscopy
| | - J Fiehler
- From the Department of Diagnostic and Interventional Neuroradiology (M.E., M.G., A.M.F., J.F., J.-H.B.), Center for Radiology and Endoscopy
| | - J-H Buhk
- From the Department of Diagnostic and Interventional Neuroradiology (M.E., M.G., A.M.F., J.F., J.-H.B.), Center for Radiology and Endoscopy
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Ernst M, Buchholz A, Bourcier R, Desal H, Le Floch PY, Möhlenbruch M, Bendszus M, Fiehler J. Voxel based analysis of recurrence dynamics in intracranial aneurysms after coiling. J Neurointerv Surg 2017; 10:571-576. [PMID: 29089416 DOI: 10.1136/neurintsurg-2017-013311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND Understanding aneurysm growth is critical for the appropriate follow-up of patients after coil embolization and the need for retreatment. The purpose of the study was to stratify the growth dynamics of aneurysm recurrences after coiling by volumetric analysis and to determine predictive factors for aneurysm recurrences. METHODS Source images of follow-up three-dimensional time of flight MR angiography (ToF-MRA) scans were compared with the first post-interventional ToF-MRA scan and analyzed for residual flow after co-registration using ANALYZE-software. In the event of incomplete occlusion, the residual volume was segmented and calculated. Growth dynamic was determined for each aneurysm after embolization. RESULTS We analyzed 326 patients with 345 aneurysms from two centers. Each case had at least two ToF-MRA examinations after endovascular therapy. The mean observation interval was 59 months. Volumetric analysis of 1139 follow-up MRAs revealed that 218/345 aneurysms (63.2%) showed complete occlusion on initial follow-up imaging, and of these 95.0% remained stable. A steady increase in intra-aneurysmal flow was observed in 83/345 (24.1%). Less frequent observations were a steep increase (21/345; 6.1%) and a decrease (27/345; 7.8%). Independent predictors of increasing residual flow were greatest aneurysm diameter, total coil length, and incomplete occlusion. CONCLUSIONS Volumetric analysis of registered three-dimensional ToF-MRA follow-up datasets allows the detection of different growth patterns with high precision, avoids the low inter-rater reliability, and represents a promising approach for future studies that include analysis of more complex predictors of residual flow. In cases of aneurysm recurrence after coiling, the major pattern seems to be a steady increase in intra-aneurysmal flow over several months.
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Affiliation(s)
- Marielle Ernst
- Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Anika Buchholz
- Department of Medical Biometry and Epidemiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Romain Bourcier
- Service de Neuroradiologie Diagnostique et Interventionnelle, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Hubert Desal
- Service de Neuroradiologie Diagnostique et Interventionnelle, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Pierre-Yves Le Floch
- Service de Neuroradiologie Diagnostique et Interventionnelle, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Markus Möhlenbruch
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Jens Fiehler
- Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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Sedlacik J, Frölich A, Spallek J, Forkert ND, Faizy TD, Werner F, Knopp T, Krause D, Fiehler J, Buhk JH. Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics. PLoS One 2016; 11:e0160097. [PMID: 27494610 PMCID: PMC4975468 DOI: 10.1371/journal.pone.0160097] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/07/2016] [Indexed: 11/25/2022] Open
Abstract
Purpose The purpose of this work was to demonstrate the capability of magnetic particle imaging (MPI) to assess the hemodynamics in a realistic 3D aneurysm model obtained by additive manufacturing. MPI was compared with magnetic resonance imaging (MRI) and dynamic digital subtraction angiography (DSA). Materials and Methods The aneurysm model was of saccular morphology (7 mm dome height, 5 mm cross-section, 3–4 mm neck, 3.5 mm parent artery diameter) and connected to a peristaltic pump delivering a physiological flow (250 mL/min) and pulsation rate (70/min). High-resolution (4 h long) 4D phase contrast flow quantification (4D pc-fq) MRI was used to directly assess the hemodynamics of the model. Dynamic MPI, MRI, and DSA were performed with contrast agent injections (3 mL volume in 3 s) through a proximally placed catheter. Results and Discussion 4D pc-fq measurements showed distinct pulsatile flow velocities (20–80 cm/s) as well as lower flow velocities and a vortex inside the aneurysm. All three dynamic methods (MPI, MRI, and DSA) also showed a clear pulsation pattern as well as delayed contrast agent dynamics within the aneurysm, which is most likely caused by the vortex within the aneurysm. Due to the high temporal resolution of MPI and DSA, it was possible to track the contrast agent bolus through the model and to estimate the average flow velocity (about 60 cm/s), which is in accordance with the 4D pc-fq measurements. Conclusions The ionizing radiation free, 4D high resolution MPI method is a very promising tool for imaging and characterization of hemodynamics in human. It carries the possibility of overcoming certain disadvantages of other modalities like considerably lower temporal resolution of dynamic MRI and limited 2D characteristics of DSA. Furthermore, additive manufacturing is the key for translating powerful pre-clinical techniques into the clinic.
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Affiliation(s)
- Jan Sedlacik
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Andreas Frölich
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Johanna Spallek
- Department of Product Development and Mechanical Engineering Design, Hamburg University of Technology, Hamburg, Germany
| | - Nils D. Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Tobias D. Faizy
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Franziska Werner
- Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
| | - Tobias Knopp
- Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
| | - Dieter Krause
- Department of Product Development and Mechanical Engineering Design, Hamburg University of Technology, Hamburg, Germany
| | - Jens Fiehler
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan-Hendrik Buhk
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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