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  • 1
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    Online Resource
    Adaptive noise cancellation to suppress electrocardiography artifacts during real‐time interventional MRI
    Wiley ; 2011
    In:  Journal of Magnetic Resonance Imaging Vol. 33, No. 5 ( 2011-05), p. 1184-1193
    Details
    In: Journal of Magnetic Resonance Imaging, Wiley, Vol. 33, No. 5 ( 2011-05), p. 1184-1193
    Abstract: To develop a system for artifact suppression in electrocardiogram (ECG) recordings obtained during interventional real‐time magnetic resonance imaging (MRI). Materials and Methods: We characterized ECG artifacts due to radiofrequency pulses and gradient switching during MRI in terms of frequency content. A combination of analog filters and digital least mean squares adaptive filters were used to filter the ECG during in vivo experiments and the results were compared with those obtained with simple low‐pass filtering. The system performance was evaluated in terms of artifact suppression and ability to identify arrhythmias during real‐time MRI. Results: Analog filters were able to suppress artifacts from high‐frequency radiofrequency pulses and gradient switching. The remaining pulse artifacts caused by intermittent preparation sequences or spoiler gradients required adaptive filtering because their bandwidth overlapped with that of the ECG. Using analog and adaptive filtering, a mean improvement of 38 dB ( n = 11, peak QRS signal to pulse artifact noise) was achieved. This filtering system was successful in removing pulse artifacts that obscured arrhythmias such as premature ventricular complexes and complete atrioventricular block. Conclusion: We have developed an online ECG monitoring system employing digital adaptive filters that enables the identification of cardiac arrhythmias during real‐time MRI‐guided interventions. J. Magn. Reson. Imaging 2011;33:1184–1193. © 2011 Wiley‐Liss, Inc.
    Type of Medium: Online Resource
    ISSN: 1053-1807 , 1522-2586
    URL: Issue
    URL: Article
    DOI: 10.1002/jmri.v33.5
    DOI: 10.1002/jmri.22530
    Language: English
    Publisher: Wiley
    Publication Date: 2011
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  • 2
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    A deflectable guiding catheter for real‐time MRI‐guided interventions
    Wiley ; 2012
    In:  Journal of Magnetic Resonance Imaging Vol. 35, No. 4 ( 2012-04), p. 908-915
    Details
    In: Journal of Magnetic Resonance Imaging, Wiley, Vol. 35, No. 4 ( 2012-04), p. 908-915
    Abstract: To design a deflectable guiding catheter that omits long metallic components yet preserves mechanical properties to facilitate therapeutic interventional MRI procedures. Materials and Methods: The catheter shaft incorporated Kevlar braiding. A 180° deflection was attained with a 5‐cm nitinol slotted tube, a nitinol spring, and a Kevlar pull string. We tested three designs: passive, passive incorporating an inductively coupled coil, and active receiver. We characterized mechanical properties, MRI properties, RF induced heating, and in vivo performance in swine. Results: Torque and tip deflection force were satisfactory. Representative procedures included hepatic and azygos vein access, laser cardiac septostomy, and atrial septal defect crossing. Visualization was best in the active configuration, delineating profile and tip orientation. The passive configuration could be used in tandem with an active guidewire to overcome its limited conspicuity. There was no RF‐induced heating in all configurations under expected use conditions in vitro and in vivo. Conclusion: Kevlar and short nitinol component substitutions preserved mechanical properties. The active design offered the best visibility and usability but reintroduced metal conductors. We describe versatile deflectable guiding catheters with a 0.057” lumen for interventional MRI catheterization. Implementations are feasible using active, inductive, and passive visualization strategies to suit application requirements. J. Magn. Reson. Imaging 2012;35:908–915. © 2011 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 1053-1807 , 1522-2586
    URL: Issue
    URL: Article
    DOI: 10.1002/jmri.v35.4
    DOI: 10.1002/jmri.23520
    Language: English
    Publisher: Wiley
    Publication Date: 2012
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  • 3
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    X‐ray fused with MRI guidance of pre‐selected transcatheter congenital heart disease interventions
    Wiley ; 2019
    In:  Catheterization and Cardiovascular Interventions Vol. 94, No. 3 ( 2019-09), p. 399-408
    Details
    In: Catheterization and Cardiovascular Interventions, Wiley, Vol. 94, No. 3 ( 2019-09), p. 399-408
    Abstract: To determine whether X‐ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions. Background Complex transcatheter interventions often require three‐dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X‐ray fluoroscopy can potentially improve and simplify procedures. Methods Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience. Results Forty‐six patients were enrolled. Pre‐catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM‐guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5–63 years]; median weight 28 kg [5.6–110 kg] ) with the following prespecified indications: pulmonary artery (PA) stenosis ( n = 13), aortic coarctation ( n = 12), conduit stenosis/insufficiency ( n = 9), and ventricular septal defect ( n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM‐guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM‐guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading. Conclusions XFM provides operators with meaningful three‐dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.
    Type of Medium: Online Resource
    ISSN: 1522-1946 , 1522-726X
    URL: Issue
    URL: Article
    DOI: 10.1002/ccd.v94.3
    DOI: 10.1002/ccd.28324
    Language: English
    Publisher: Wiley
    Publication Date: 2019
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  • 4
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    Acute Cardiac MRI Assessment of Radiofrequency Ablation Lesions for Pediatric Ventricular Arrhythmia: Feasibility and Clinical Correlation
    Wiley ; 2017
    In:  Journal of Cardiovascular Electrophysiology Vol. 28, No. 5 ( 2017-05), p. 517-522
    Details
    In: Journal of Cardiovascular Electrophysiology, Wiley, Vol. 28, No. 5 ( 2017-05), p. 517-522
    Abstract: Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence. Methods This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid‐term arrhythmia recurrences were assessed. Results Patient characteristics include median age 14 years (1–18 years), median weight 52 kg (11–81 kg), normal cardiac anatomy (n = 6), d‐transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia‐free at median 7 months follow‐up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure. Conclusions Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.
    Type of Medium: Online Resource
    ISSN: 1045-3873 , 1540-8167
    URL: Issue
    URL: Article
    DOI: 10.1111/jce.2017.28.issue-5
    DOI: 10.1111/jce.13197
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2037519-0
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  • 5
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    Bronchus compression relieved by patent ductus arteriosus stenting
    Wiley ; 2020
    In:  Catheterization and Cardiovascular Interventions Vol. 96, No. 7 ( 2020-12), p. 1434-1438
    Details
    In: Catheterization and Cardiovascular Interventions, Wiley, Vol. 96, No. 7 ( 2020-12), p. 1434-1438
    Abstract: Patent ductus arteriosus (PDA) stenting is evolving as an alternative to surgical aorto‐pulmonary shunts for infants with ductal‐dependent pulmonary blood flow. Given anatomical proximity, the PDA can compress the ipsilateral bronchus. We report a case series of four patients with bronchial compression by a tortuous PDA who underwent PDA stenting. Methods Our four patients received PDA stents for ductal‐dependent pulmonary blood flow despite preprocedure imaging evidence of bronchial compression. We reviewed the cross‐sectional chest imaging to assess the degree of bronchial compression and the variables that affect it, namely PDA size, PDA tortuosity, and the anatomical relationship between the compressed bronchus and the PDA. Results Three out of the four patients had postprocedure imaging, and all showed relief of the previously seen bronchial compression. Post‐PDA stenting patients had a smaller and straight PDA with significant lateralization away from the compressed bronchus. None of the four patients developed symptoms of bronchial compression poststenting. Conclusions Our study suggests that pre‐existing bronchial compression does not preclude PDA stenting. Stent placement in an engorged and tortuous PDA led to significant improvement in pre‐existing bronchial compression. Improvement may be attributed to PDA shrinkage, straightening, and lateralization. Further studies are needed to confirm our findings.
    Type of Medium: Online Resource
    ISSN: 1522-1946 , 1522-726X
    URL: Issue
    URL: Article
    DOI: 10.1002/ccd.v96.7
    DOI: 10.1002/ccd.29274
    Language: English
    Publisher: Wiley
    Publication Date: 2020
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  • 6
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    Early experience with the Micro Plug Set for preterm patent ductus arteriosus closure
    Wiley ; 2020
    In:  Catheterization and Cardiovascular Interventions Vol. 96, No. 7 ( 2020-12), p. 1439-1444
    Details
    In: Catheterization and Cardiovascular Interventions, Wiley, Vol. 96, No. 7 ( 2020-12), p. 1439-1444
    Abstract: We intend to describe early experience using a new, commercially available Micro Plug Set for preterm neonate and infant transcatheter patent ductus arteriosus (PDA) occlusion. Background Transcatheter PDA occlusion in premature neonates and small infants is safe and effective. The procedure is early in its evolution. Methods Procedural and short‐term outcomes of preterm neonates and infants undergoing transcatheter PDA occlusion with a new, commercially available device were reviewed. Results Eight preterm neonates and infants born at median 27 weeks gestation (23–36 weeks) underwent transcatheter PDA device closure with the Micro Plug Set. The device is short (2.5 mm) with a range of diameters (3, 4, 5, 6 mm) and delivered through a microcatheter. Procedures were performed at median 41 days of age (12–88 days) and at 1690 g (760–3,310 g). Transvenous PDA device occlusion was performed with fluoroscopic and echocardiography guidance. All procedures were successful with complete PDA occlusion. There were no procedural or short‐term adverse events. Conclusions Preterm neonate and infant transcatheter PDA device closure with a new, commercially available short and microcatheter delivered device (Micro Plug Set) was safe and effective in a small, early series of patients.
    Type of Medium: Online Resource
    ISSN: 1522-1946 , 1522-726X
    URL: Issue
    URL: Article
    DOI: 10.1002/ccd.v96.7
    DOI: 10.1002/ccd.29298
    Language: English
    Publisher: Wiley
    Publication Date: 2020
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  • 7
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    Limitations of closing percutaneous transthoracic ventricular access ports using a commercial collagen vascular closure device
    Wiley ; 2011
    In:  Catheterization and Cardiovascular Interventions Vol. 77, No. 7 ( 2011-06-01), p. 1079-1085
    Details
    In: Catheterization and Cardiovascular Interventions, Wiley, Vol. 77, No. 7 ( 2011-06-01), p. 1079-1085
    Type of Medium: Online Resource
    ISSN: 1522-1946
    URL: Article
    DOI: 10.1002/ccd.22941
    Language: English
    Publisher: Wiley
    Publication Date: 2011
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  • 8
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    Virtual dye angiography: Flow visualization for MRI‐guided interventions
    Wiley ; 2012
    In:  Magnetic Resonance in Medicine Vol. 67, No. 4 ( 2012-04), p. 1013-1021
    Details
    In: Magnetic Resonance in Medicine, Wiley, Vol. 67, No. 4 ( 2012-04), p. 1013-1021
    Abstract: In magnetic resonance imaging‐guided cardiovascular interventional procedures, it is valuable to be able to visualize blood flow immediately and interactively in selected regions. In particular, it is useful to assess normal or pathological communications between specific heart chambers and vessels. Phase‐contrast velocity mapping is not suitable for this purpose as it requires too much data and is not capable of determining directly if blood originating in one location travels to a nearby location. This article presents a novel flow visualization method called virtual dye angiography that enables visualization of blood flow analogous to selective catheter angiography. The method uses two‐dimensional radio frequency pulses to achieve interactive, intermittent, targeted saturation of a localized region of the blood pool. The flow of the saturated spins is observed directly on real‐time images or, in an enhanced manner, using ECG synchronized background subtraction. The modular nature of the technique allows for easy and seamless integration into a real‐time, interactive imaging system with minimal overhead. We present initial results in animals and in a healthy human volunteer. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    URL: Article
    DOI: 10.1002/mrm.v67.4
    DOI: 10.1002/mrm.23078
    Language: English
    Publisher: Wiley
    Publication Date: 2012
    detail.hit.zdb_id: 1493786-4
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  • 9
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    MRI‐guided vascular access with an active visualization needle
    Wiley ; 2011
    In:  Journal of Magnetic Resonance Imaging Vol. 34, No. 5 ( 2011-11), p. 1159-1166
    Details
    In: Journal of Magnetic Resonance Imaging, Wiley, Vol. 34, No. 5 ( 2011-11), p. 1159-1166
    Abstract: To develop an approach to vascular access under magnetic resonance imaging (MRI), as a component of comprehensive MRI‐guided cardiovascular catheterization and intervention. Materials and Methods: We attempted jugular vein access in healthy pigs as a model of “difficult” vascular access. Procedures were performed under real‐time MRI guidance using reduced field of view imaging. We developed an “active” MRI antenna‐needle having an open‐lumen, distinct tip appearance and indicators of depth and trajectory in order to enhance MRI visibility during the procedure. We compared performance of the active needle against an unmodified commercial passively visualized needle, measured by procedure success among operators with different levels of experience. Results: MRI‐guided central vein access was feasible using both the active needle and the unmodified passive needle. The active needle required less time (88 vs. 244 sec, P = 0.022) and fewer needle passes (4.5 vs. 9.1, P = 0.028), irrespective of operator experience. Conclusion: MRI‐guided access to central veins is feasible in our animal model. When image guidance is necessary for vascular access, performing this component under MRI will allow wholly MRI‐guided catheterization procedures that do not require adjunctive imaging facilities such as x‐ray or ultrasound. The active needle design showed enhanced visibility, as expected. These capabilities may permit more complex catheter‐based cardiovascular interventional procedures enabled by enhanced image guidance. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 1053-1807 , 1522-2586
    URL: Issue
    URL: Article
    DOI: 10.1002/jmri.v34.5
    DOI: 10.1002/jmri.22715
    Language: English
    Publisher: Wiley
    Publication Date: 2011
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  • 10
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    Integration of cardiac and respiratory motion into MRI roadmaps fused with x‐ray
    Wiley ; 2013
    In:  Medical Physics Vol. 40, No. 3 ( 2013-03)
    Details
    In: Medical Physics, Wiley, Vol. 40, No. 3 ( 2013-03)
    Abstract: Volumetric roadmaps overlaid on live x‐ray fluoroscopy may be used to enhance image guidance during interventional procedures. These roadmaps are often static and do not reflect cardiac or respiratory motion. In this work, the authors present a method for integrating cardiac and respiratory motion into magnetic resonance imaging (MRI)‐derived roadmaps to fuse with live x‐ray fluoroscopy images, and this method was tested in large animals. Methods: Real‐time MR images were used to capture cardiac and respiratory motion. Nonrigid registration was used to calculate motion fields to deform a reference end‐expiration, end‐diastolic image to different cardiac and respiratory phases. These motion fields were fit to separate affine motion models for the aorta and proximal right coronary artery. Under x‐ray fluoroscopy, an image‐based navigator and ECG signal were used as inputs to deform the roadmap for live overlay. The in vivo accuracy of motion correction was measured in four swine as the ventilator tidal volume was varied. Results: Motion correction reduced the root‐mean‐square error between the roadmaps and manually drawn centerlines, even under high tidal volume conditions. For the aorta, the error was reduced from 2.4 ± 1.5 mm to 2.2 ± 1.5 mm ( p 〈 0.05). For the proximal right coronary artery, the error was reduced from 8.8 ± 16.2 mm to 4.3 ± 5.2 mm ( p 〈 0.001). Using real‐time MRI and an affine motion model it is feasible to incorporate physiological cardiac and respiratory motion into MRI‐derived roadmaps to provide enhanced image guidance for interventional procedures. Conclusions: A method has been presented for creating dynamic 3D roadmaps that incorporate cardiac and respiratory motion. These roadmaps can be overlaid on live X‐ray fluoroscopy to enhance image guidance for cardiac interventions.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Article
    DOI: 10.1118/1.4789919
    Language: English
    Publisher: Wiley
    Publication Date: 2013
    detail.hit.zdb_id: 1466421-5
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