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Burkhardt BEU, Brown NK, Carberry JE, Velasco Forte MN, Byrne N, Greil G, Hussain T, Tandon A. Creating three dimensional models of the right ventricular outflow tract: influence of contrast, sequence, operator, and threshold. Int J Cardiovasc Imaging 2019; 35:2067-2076. [PMID: 31203535 DOI: 10.1007/s10554-019-01646-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/07/2019] [Indexed: 11/29/2022]
Abstract
The use of 3D printed models of the right ventricular outflow tract (RVOT) for surgical and interventional planning is growing and often requires image segmentation of cardiac magnetic resonance (CMR) images. Segmentation results may vary based on contrast, image sequence, signal threshold chosen by the operator, and manual post-processing. The purpose of this study was to determine potential biases and post-processing errors in image segmentation to enable informed decisions. Models of the RVOT and pulmonary arteries from twelve patients who had contrast enhanced CMR angiography with gadopentetate dimeglumine (GPD), gadofosveset trisodium (GFT), and a post-GFT inversion-recovery (IR) whole heart sequence were segmented, trimmed, and aligned by three operators. Geometric agreement and minimal RVOT diameters were compared between sequences and operators. To determine the contribution of threshold, interoperator variability was compared between models created by the same two operators using the same versus different thresholds. Geometric agreement by Dice between objects was high (intraoperator: 0.89-0.95; interoperator: 0.95-0.97), without differences between sequences. Minimal RVOT diameters differed on average by - 1.9 to - 1.3 mm (intraoperator) and by 0.4 to 1.4 mm (interoperator). The contribution of threshold to interoperator geometric agreement was not significant (same threshold: 0.96 ± 0.06, different threshold: 0.93 ± 0.05; p = 0.181), but minimal RVOT diameters were more variable with different versus constant thresholds (- 9.12% vs. 2.42%; p < 0.05). Thresholding does not significantly change interoperator variability for geometric agreement, but does for minimal RVOT diameter. Minimal RVOT diameters showed clinically relevant variation within and between operators.
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Affiliation(s)
- Barbara E U Burkhardt
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Pediatric Cardiology, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Steinwiesstr. 75, 8032, Zurich, Switzerland.
| | - Nicholas K Brown
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jaclyn E Carberry
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | | | - Nicholas Byrne
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | - Gerald Greil
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.,Department of Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tarique Hussain
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.,Department of Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Animesh Tandon
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Burkhardt BE, Byrne N, Velasco Forte MN, Iannaccone F, De Beule M, Morgan GJ, Hussain T. Evaluation of a modified Cheatham-Platinum stent for the treatment of aortic coarctation by finite element modelling. JRSM Cardiovasc Dis 2018; 7:2048004018773958. [PMID: 29760913 PMCID: PMC5944143 DOI: 10.1177/2048004018773958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 02/05/2018] [Accepted: 03/21/2018] [Indexed: 11/21/2022] Open
Abstract
Objectives Stent implantation for the treatment of aortic coarctation has become a standard approach for the management of older children and adults. Criteria for optimal stent design and construction remain undefined. This study used computational modelling to compare the performance of two generations of the Cheatham-Platinum stent (NuMED, Hopkinton, NY, USA) deployed in aortic coarctation using finite element analysis. Design Three-dimensional models of both stents, reverse engineered from microCT scans, were implanted in the aortic model of one representative patient. They were virtually expanded in the vessel with a 16 mm balloon and a pressure of 2 atm. Results The conventional stent foreshortened to 96.5% of its initial length, whereas the new stent to 99.2% of its initial length. Diameters in 15 slices across the conventional stent were 11.6–15 mm (median 14.2 mm) and slightly higher across the new stent: 10.7–15.3 mm (median 14.5 mm) (p= 0.021). Apposition to the vessel wall was similar: conventional stent 31.1% and new stent 28.6% of total stent area. Conclusions The new design Cheatham-Platinum stent showed similar deployment results compared to the conventional design. The new stent design showed slightly higher expansion, using the same delivery balloon. Patient-specific computational models can be used for virtual implantation of new aortic stents and promise to inform subsequent in vivo trials.
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Affiliation(s)
- Barbara Eu Burkhardt
- Department of Pediatrics, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Nicholas Byrne
- Division of Imaging Sciences and Biomedical Engineering, King's College, London, UK
| | | | | | | | - Gareth J Morgan
- The Heart Institute, Children's Hospital of Colorado, Anschutz Medical Campus, Denver, CO, USA
| | - Tarique Hussain
- Department of Pediatrics, University of Texas Southwestern Medical Centre, Dallas, TX, USA
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Burkhardt BEU, Velasco Forte MN, Durairaj S, Rafiq I, Valverde I, Tandon A, Simpson J, Hussain T. Timely Pulmonary Valve Replacement May Allow Preservation of Left Ventricular Circumferential Strain in Patients with Tetralogy of Fallot. Front Pediatr 2017; 5:39. [PMID: 28293551 PMCID: PMC5328989 DOI: 10.3389/fped.2017.00039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/13/2017] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Patients with Tetralogy of Fallot (TOF) and pulmonary insufficiency and a dilated right ventricle (RV) may suffer from a reduction in left ventricular (LV) performance. It is not clear whether timely pulmonary valve replacement (PVR) preserves LV mechanics. METHODS Ten TOF patients who underwent PVR were identified from hospital records, and pre- and postoperative cardiac magnetic resonance images were post-processed with a semi-automatic tissue tracking software. LV circumferential strain, time to peak strain, and torsion were compared before and after PVR. A control group of 10 age-matched normal volunteers was assessed as a comparison. RESULTS LV circumferential strain did not change before vs. after PVR (basal -18.3 ± 3.7 vs. -20.5 ± 3%, p = 0.082; mid-ventricular -18.4 ± 3.6 vs. -19.1 ± 2%, p = 0.571; apical -22.7 ± 5.2 vs. -22.1 ± 4%; p = 0.703). There was also no difference seen between the baseline strain and normal controls (control basal -18.2 ± 3.3%, p = 0.937; mid -18 ± 3.2%, p = 0.798; apex -24.1 ± 5%, p = 0.552). LV torsion remained unchanged from baseline to post PVR [systolic 2.75 (1.23-9.51) °/cm vs. 2.3 ± 1.2°/cm, p = 0.285; maximum 5.5 ± 3.5°/cm vs. 2.34 (1.37-8.07) °/cm, p = 0.083]. There was no difference in time to measured peak LV circumferential strain before vs. after PVR (basal 0.44 ± 0.1 vs. 0.43 ± 0.05, p = 0.912; mid-ventricular 0.42 ± 0.08 vs. 0.38 ± 0.06, p = 0.186; apical 0.40 ± 0.08 vs. 0.40 ± 0.06, p = 0.995). At the same time, pulmonary regurgitation and RV end-diastolic and end-systolic volume indices decreased and LV end-diastolic volume increased after PVR. RV and LV ejection fractions remained constant. CONCLUSION PVR allows for favorable remodeling of both ventricular volumes for TOF patients with significant pulmonary regurgitation. In this cohort, LV myocardial functional parameters such as circumferential strain, time to peak strain, and LV torsion were normal at baseline and remain unchanged after PVR.
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Affiliation(s)
- Barbara E U Burkhardt
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland
| | | | - Saravanan Durairaj
- Division of Imaging Sciences and Biomedical Engineering, King's College London , London , UK
| | - Isma Rafiq
- Division of Imaging Sciences and Biomedical Engineering, King's College London , London , UK
| | - Israel Valverde
- Division of Imaging Sciences and Biomedical Engineering, King's College London , London , UK
| | - Animesh Tandon
- Department of Pediatrics, University of Texas Southwestern Medical Center , Dallas, TX , USA
| | - John Simpson
- Division of Imaging Sciences and Biomedical Engineering, King's College London , London , UK
| | - Tarique Hussain
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
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