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Bates AJ, Schuh A, McConnell K, Williams BM, Lanier JM, Willmering MM, Woods JC, Fleck RJ, Dumoulin CL, Amin RS. A novel method to generate dynamic boundary conditions for airway CFD by mapping upper airway movement with non-rigid registration of dynamic and static MRI. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3144. [PMID: 30133165 DOI: 10.1002/cnm.3144] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/21/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Computational fluid dynamics (CFD) simulations of airflow in the human airways have the potential to provide a great deal of information that can aid clinicians in case management and surgical decision making, such as airway resistance, energy expenditure, airflow distribution, heat and moisture transfer, and particle deposition, as well as the change in each of these due to surgical interventions. However, the clinical relevance of CFD simulations has been limited to date, as previous models either did not incorporate neuromuscular motion or any motion at all. Many common airway pathologies, such as obstructive sleep apnea (OSA) and tracheomalacia, involve large movements of the structures surrounding the airway, such as the tongue and soft palate. Airway wall motion may be due to many factors including neuromuscular motion, internal aerodynamic forces, and external forces such as gravity. Therefore, to realistically model these airway diseases, a method is required to derive the airway wall motion, whatever the cause, and apply it as a boundary condition to CFD simulations. This paper presents and validates a novel method of capturing in vivo motion of airway walls from magnetic resonance images with high spatiotemporal resolution, through a novel combination of non-rigid image, surface, and surface-normal-vector registration. Coupled with image-synchronous pneumotachography, this technique provides the necessary boundary conditions for dynamic CFD simulations of breathing, allowing the effect of the airway's complex motion to be calculated for the first time, in both normal subjects and those with conditions such as OSA.
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Affiliation(s)
- Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Bioengineering, Imperial College London, UK
| | - Andreas Schuh
- Department of Computing, Imperial College London, UK
| | - Keith McConnell
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Brynne M Williams
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - J Matthew Lanier
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew M Willmering
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
- Departments of Radiology and Physics, University of Cincinnati, Cincinnati, OH, USA
| | - Robert J Fleck
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, University of Cincinnati, Cincinnati, OH, USA
| | - Charles L Dumoulin
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
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Wagshul ME, Sin S, Lipton ML, Shifteh K, Arens R. Novel retrospective, respiratory-gating method enables 3D, high resolution, dynamic imaging of the upper airway during tidal breathing. Magn Reson Med 2013; 70:1580-90. [PMID: 23401041 DOI: 10.1002/mrm.24608] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 11/29/2012] [Accepted: 11/30/2012] [Indexed: 12/27/2022]
Abstract
PURPOSE A retrospective, respiratory-gated technique for measuring dynamic changes in the upper airway over the respiratory cycle was developed, with the ultimate goal of constructing anatomically and functionally accurate upper airway models in obstructive sleep apnea patients. METHODS Three-dimensional cine, retrospective respiratory-gated, gradient echo imaging was performed in six adolescents being evaluated for polycystic ovary syndrome, a disorder with a high obstructive sleep apnea prevalence. A novel retrospective gating scheme, synchronized to flow from a nasal cannula, limited image acquisition to predefined physiological ranges. Images were evaluated with respect to contrast, airway signal leakage, and demonstration of dynamic airway area changes. RESULTS Two patients were diagnosed with obstructive sleep apnea. Motion artifacts were absent in all image sets. Scan efficiency ranged from 48 to 88%. Soft tissue-to-airway contrast-to-noise ratio varied from 6.1 to 9.6. Airway signal leakage varied between 10 and 17% of soft tissue signal. Automated segmentation allowed calculation of airway area changes over the respiratory cycle. In one severe apnea patient, the technique allowed demonstration of asynchronous airway expansion and contraction above and below a severe constriction. CONCLUSIONS Retrospective, respiratory gated imaging of the upper airway has been demonstrated, utilizing a gating algorithm to ensure acquisition over specified ranges of respiratory rate and tidal volume.
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Affiliation(s)
- Mark E Wagshul
- Department of Radiology, Gruss MRRC, Albert Einstein College of Medicine, Bronx, New York, USA; Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, USA
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Findings on MR Sleep Studies as Biomarkers to Predict Outcome of Genioglossus Advancement in the Treatment of Obstructive Sleep Apnea in Children and Young Adults. AJR Am J Roentgenol 2010; 194:1204-9. [DOI: 10.2214/ajr.09.3254] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Correlation between the severity of sleep apnea and upper airway morphology in pediatric and adult patients. Curr Opin Allergy Clin Immunol 2010; 10:26-33. [DOI: 10.1097/aci.0b013e328334f659] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Mahmoud M, Gunter J, Donnelly LF, Wang Y, Nick TG, Sadhasivam S. A Comparison of Dexmedetomidine with Propofol for Magnetic Resonance Imaging Sleep Studies in Children. Anesth Analg 2009; 109:745-53. [DOI: 10.1213/ane.0b013e3181adc506] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Fricke BL, Abbott MB, Donnelly LF, Dardzinski BJ, Poe SA, Kalra M, Amin RS, Cotton RT. Upper airway volume segmentation analysis using cine MRI findings in children with tracheostomy tubes. Korean J Radiol 2007; 8:506-11. [PMID: 18071281 PMCID: PMC2627453 DOI: 10.3348/kjr.2007.8.6.506] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 02/27/2007] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway. MATERIALS AND METHODS Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test). RESULTS Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes. CONCLUSION There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.
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Affiliation(s)
- Bradley L. Fricke
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- Current Location: Department of Radiology, Emory University School of Medicine, Atlanta GA 30322, USA
| | - M. Bret Abbott
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- Current Location: Department of Radiology, University of Arizona College of Medicine, Tucson AZ 85724-5067, USA
| | - Lane F. Donnelly
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Bernard J. Dardzinski
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Stacy A. Poe
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
| | - Maninder Kalra
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
- Department of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
| | - Raouf S. Amin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
- Department of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
| | - Robin T. Cotton
- Department of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
- Department of Otolaryngology, Cincinnati Children's Hospital Medical Center, Cincinnati OH 45229-3039, USA
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Kalra M, Donnelly LF, McConnell K, O'Brien K, Sandhu J, Johnson J, Amin RS. Determination of respiratory phase during acquisition of airway cine MR images. Pediatr Radiol 2006; 36:965-9. [PMID: 16807717 DOI: 10.1007/s00247-006-0241-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 04/17/2006] [Accepted: 04/27/2006] [Indexed: 11/25/2022]
Abstract
Subjects were imaged on a 1.5-T Signa MRI system using the head-neck vascular coil. An axial fast gradient echo cine, at the base of the second cervical vertebra, was obtained. A total of 128 images were acquired with a rapid image acquisition (one per second) over several respiratory cycles. The analog signal from the MR scanner (RF unblank) was utilized to determine the duration of the cine MR sequence. The phase of respiration was determined by analyzing the nasal air flow connected via pressure tubing to a pressure transducer outside the MR scanner room. We were thus able to determine the phase of respiration during acquisition of individual airway cine MR images. There was a wide range of airway volume measurements over the respiratory cycle with the lowest volume at end expiration and the highest at peak inspiration.
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Affiliation(s)
- Maninder Kalra
- Division of Pulmonary Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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Fricke BL, Donnelly LF, Shott SR, Kalra M, Poe SA, Chini BA, Amin RS. Comparison of lingual tonsil size as depicted on MR imaging between children with obstructive sleep apnea despite previous tonsillectomy and adenoidectomy and normal controls. Pediatr Radiol 2006; 36:518-23. [PMID: 16596369 DOI: 10.1007/s00247-006-0149-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/01/2006] [Accepted: 02/16/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Cine MRI has become a useful tool in the evaluation of patients with persistent obstructive sleep apnea (OSA) despite previous surgical intervention and in patients with underlying conditions that render them susceptible to multilevel airway obstruction. Findings on cine MRI studies have also increased our understanding of the mechanisms and anatomic causes of OSA in children. OBJECTIVE To compare lingual tonsil size between children with OSA and a group of normal controls. In addition, a subanalysis was made of the group of children with OSA comparing lingual tonsils between children with and without underlying Down syndrome. MATERIALS AND METHODS Children with persistent OSA despite previous palatine tonsillectomy and adenoidectomy and controls without OSA underwent MR imaging with sagittal fast spin echo inversion-recovery images, and lingual tonsils were categorized as nonperceptible at imaging or present and measurable. When present, lingual tonsils were measured in the maximum anterior-posterior diameter. If lingual tonsils were greater than 10 mm in diameter and abutting both the posterior border of the tongue and the posterior pharyngeal wall, they were considered markedly enlarged. RESULTS There were statistically significant differences between the OSA and control groups for the presence vs. nonvisualization of lingual tonsils (OSA 33% vs. control 0%, P=0.0001) and mean diameter of the lingual tonsils (OSA 9.50 mm vs. control 0.0 mm, P=0.00001). Within the OSA group, there were statistically significant differences between children with and without Down syndrome for the three lingual tonsil width categories (P=0.0070) and occurrence of markedly enlarged lingual tonsils (with Down syndrome 35% vs. without Down syndrome 3%, P=0.0035). CONCLUSIONS Enlargement of the lingual tonsils is relatively common in children with persistent obstructive sleep apnea after palatine tonsillectomy and adenoidectomy. This is particularly true in patients with Down syndrome.
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Affiliation(s)
- Bradley L Fricke
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
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Abstract
Cine magnetic resonance (MR) imaging sleep studies have become a useful tool in the evaluation of obstructive sleep apnea in children with certain categories of pathologic conditions. In this article, the author describes a program for the use of cine MR sleep studies in the evaluation of children with obstructive sleep apnea. The following areas are discussed: clinical indications, patient preparation, anatomic considerations, MR technique, technical issues, image interpretation, commonly encountered diagnoses, volume segmentation processing of data, and controversial areas.
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Affiliation(s)
- Lane F Donnelly
- Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 5031, Cincinnati, OH, 45229-3039, USA.
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Abbott MB, Donnelly LF, Dardzinski BJ, Poe SA, Chini BA, Amin RS. Obstructive Sleep Apnea: MR Imaging Volume Segmentation Analysis. Radiology 2004; 232:889-95. [PMID: 15333801 DOI: 10.1148/radiol.2323031581] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To retrospectively determine airway wall motion with volume segmentation of transverse cine magnetic resonance (MR) images in children with obstructive sleep apnea (OSA). MATERIALS AND METHODS Transverse fast gradient-echo cine MR images of the hypopharynx were obtained at 1.5 T in 31 children with OSA (eight girls, 23 boys; mean age, 11.3 years) and 21 children free of airway symptoms who underwent MR imaging for other clinical indications (11 girls, 10 boys; mean age, 3.5 years). Volume segmentation with a k-means clustering algorithm was applied to transverse cine MR images to quantify airway volumes at each time. Airway wall motion for each child was described with standard deviation and range. Coefficient of variance and normalized range, which are independent of airway size, were used to compare groups (Kruskal-Wallis test). RESULTS Plots of airway volume over time demonstrated large fluctuations during respiration in children with OSA and minimal fluctuations in controls; findings were consistent with airway distention and airway collapse in OSA. Average airway transverse volume was larger in the group with OSA than in the control group (OSA group, 2.52 mL; control group, 0.936 mL; P <.001). Mean standard deviation (OSA group, 0.840 mL; control group, 0.17 mL; P <.001) and mean range of airway cross section (OSA group, 3.552 mL; control group, 0.864 mL; P <.001) were larger in the group with OSA. Coefficient of variance (OSA group, 0.32; control group, 0.17; P <.001) and normalized range (OSA group, 1.42; control group, 0.96; P <.001) indicate statistically significant difference in airway dynamics in children with OSA. CONCLUSION Volume segmentation of transverse cine MR images of the hypopharynx aids in quantification of increased airway wall motion in children with OSA. Transverse MR imaging demonstrates both airway distention and collapse in children with OSA.
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Affiliation(s)
- M Bret Abbott
- Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3090, USA
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Current awareness in NMR in biomedicine. NMR IN BIOMEDICINE 2003; 16:510-517. [PMID: 14719526 DOI: 10.1002/nbm.806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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