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Hewlett M, Oran O, Liu J, Drangova M. Prospective motion correction for brain MRI using spherical navigators. Magn Reson Med 2024; 91:1528-1540. [PMID: 38174443 DOI: 10.1002/mrm.29961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/24/2023] [Accepted: 11/20/2023] [Indexed: 01/05/2024]
Abstract
PURPOSE To demonstrate for the first time the feasibility of performing prospective motion correction using spherical navigators (SNAVs). METHODS SNAVs were interleaved in a 3D FLASH sequence with an additional short baseline scan (6.8 s) for fast rotation estimation. Assessment of SNAV-based prospective motion correction was performed in six volunteers. Participant motion was guided using randomly generated stepwise prompts as well as prompts derived from real motion cases. Experiments were performed on a 3 T MRI scanner using a 32-channel head coil. RESULTS When optimized for real-time application, SNAV-based motion estimates were computed in 25.8 ± 1.3 ms. Phantom-based quantification of rotation and translation accuracy indicated mean absolute errors of 0.10 ± 0.09° and 0.25 ± 0.14 mm, respectively. Implementing SNAV-based motion estimates for prospective motion correction led to a clear improvement in image quality with minimal increase in scan time (<5%). CONCLUSION Optimization of SNAV processing for real-time application enables prospective motion correction with low latency and minimal scan time requirements.
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Affiliation(s)
- Miriam Hewlett
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Omer Oran
- Siemens Healthcare Limited, Oakville, Ontario, Canada
| | - Junmin Liu
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
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2
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Grolman E, Sirianni QEA, Dunmore-Buyze J, Cruje C, Drangova M, Gillies ER. Depolymerizing self-immolative polymeric lanthanide chelates for vascular imaging. Acta Biomater 2023; 169:530-541. [PMID: 37507034 DOI: 10.1016/j.actbio.2023.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/03/2023] [Accepted: 07/22/2023] [Indexed: 07/30/2023]
Abstract
Medical imaging is widely used clinically and in research to understand disease progression and monitor responses to therapies. Vascular imaging enables the study of vascular disease and therapy, but exogenous contrast agents are generally needed to distinguish the vasculature from surrounding soft tissues. Lanthanide-based agents are commonly employed in MRI, but are also of growing interest for micro-CT, as the position of their k-edges allows them to provide enhanced contrast and also to be employed in dual-energy micro-CT, a technique that can distinguish contrast-enhanced blood vessels from tissues such as bone. Small molecule Gd3+ chelates are available, but are excreted too rapidly. At the same time, a lack of rapid clearance from the body for long-circulating agents presents toxicity concerns. To address these challenges, we describe here the use of self-immolative polymers for the development of new degradable chelates that depolymerize completely from end-to-end following the cleavage of a single end-cap from the polymer terminus. We demonstrate that tuning the end-cap allows the rate of depolymerization to be controlled, while tuning the polymer length enables the polymer to exhibit long circulation times in the blood of mice. After successfully providing one hour of blood contrast, depolymerization led to excretion of the resulting small molecule chelates into the bladder. Despite the high doses required for micro-CT, the agents were well tolerated in mice. Thus, these self-immolative polymeric chelates provide a new platform for the development of medical imaging contrast agents. STATEMENT OF SIGNIFICANCE: Vascular imaging is used clinically to diagnose and monitor vascular disease and in research to understand the progression of disease and study responses to new therapies. For techniques such as magnetic resonance imaging and x-ray computed tomography (CT), long circulating contrast agents are needed to differentiate the vasculature from surrounding tissues. However, if these agents are not rapidly excreted from the body, they can lead to toxicity. We present here a new polymeric system that can chelate hundreds of lanthanide ions for imaging contrast and can circulate for one hour in the blood, but then after end-cap cleavage breaks down completely into small molecules for excretion. The successful application of this system in micro-CT in mice is demonstrated.
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Affiliation(s)
- Eric Grolman
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B9, Canada; Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Quinton E A Sirianni
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Joy Dunmore-Buyze
- Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Charmainne Cruje
- Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5C1, Canada
| | - Maria Drangova
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B9, Canada; Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada; Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5C1, Canada.
| | - Elizabeth R Gillies
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B9, Canada; Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada; Department of Chemical and Biochemical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B9, Canada.
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Christiansen SD, Liu J, Bullrich MB, Sharma M, Boulton M, Pandey SK, Sposato LA, Drangova M. Deep learning prediction of stroke thrombus red blood cell content from multiparametric MRI. Interv Neuroradiol 2022:15910199221140962. [PMID: 36437762 DOI: 10.1177/15910199221140962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND AND PURPOSE Thrombus red blood cell (RBC) content has been shown to be a significant factor influencing the efficacy of acute ischemic stroke treatment. In this study, our objective was to evaluate the ability of convolutional neural networks (CNNs) to predict ischemic stroke thrombus RBC content using multiparametric MR images. MATERIALS AND METHODS Retrieved stroke thrombi were scanned ex vivo using a three-dimensional multi-echo gradient echo sequence and histologically analyzed. 188 thrombus R2*, quantitative susceptibility mapping and late-echo GRE magnitude image slices were used to train and test a 3-layer CNN through cross-validation. Data augmentation techniques involving input equalization and random image transformation were employed to improve network performance. The network was assessed for its ability to quantitatively predict RBC content and to classify thrombi into RBC-rich and RBC-poor groups. RESULTS The CNN predicted thrombus RBC content with an accuracy of 62% (95% CI 48-76%) when trained on the original dataset and improved to 72% (95% CI 60-84%) on the augmented dataset. The network classified thrombi as RBC-rich or poor with an accuracy of 71% (95% CI 58-84%) and an area under the curve of 0.72 (95% CI 0.57-0.87) when trained on the original dataset and improved to 80% (95% CI 69-91%) and 0.84 (95% CI 0.73-0.95), respectively, on the augmented dataset. CONCLUSIONS The CNN was able to accurately predict thrombus RBC content using multiparametric MR images, and could provide a means to guide treatment strategy in acute ischemic stroke.
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Affiliation(s)
- Spencer D Christiansen
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, 6221Western University, London, Ontario, Canada
| | - Junmin Liu
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Maria Bres Bullrich
- Department of Clinical Neurological Sciences, 6221Western University, London, Ontario, Canada
| | - Manas Sharma
- Department of Medical Imaging, 6221Western University, London, Ontario, Canada
| | - Melfort Boulton
- Department of Clinical Neurological Sciences, 6221Western University, London, Ontario, Canada
| | - Sachin K Pandey
- Department of Medical Imaging, 6221Western University, London, Ontario, Canada
| | - Luciano A Sposato
- Department of Clinical Neurological Sciences, 6221Western University, London, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, 6221Western University, London, Ontario, Canada
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4
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Hong G, Liu J, Cobos SF, Khazaee T, Drangova M, Holdsworth DW. Effective magnetic susceptibility of 3D-printed porous metal scaffolds. Magn Reson Med 2022; 87:2947-2956. [PMID: 35076107 DOI: 10.1002/mrm.29136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE 3D-printed porous metal scaffolds are a promising emerging technology in orthopedic implant design. Compared to solid metal implants, porous metal implants have lower magnetic susceptibility values, which have a direct impact on imaging time and image quality. The purpose of this study is to determine the relationship between porosity and effective susceptibility through quantitative estimates informed by comparing coregistered scanned and simulated field maps. METHODS Five porous scaffold cylinders were designed and 3D-printed in titanium alloy (Ti-6Al-4V) with nominal porosities ranging from 60% to 90% using a cellular sheet-based gyroid design. The effective susceptibility of each cylinder was estimated by comparing acquired B0 field maps against simulations of a solid cylinder of varying assigned magnetic susceptibility, where the orientation and volume of interest of the simulations was informed by a custom alignment phantom. RESULTS Magnitude images and field maps showed obvious decreases in artifact size and field inhomogeneity with increasing porosity. The effective susceptibility was found to be linearly correlated with porosity (R2 = 0.9993). The extrapolated 100% porous (no metal) magnetic susceptibility was -9.9 ppm, closely matching the expected value of pure water (-9 ppm), indicating a reliable estimation of susceptibility. CONCLUSION Effective susceptibility of porous metal scaffolds is linearly correlated with porosity. Highly porous implants have sufficiently low effective susceptibilities to be more amenable to routine imaging with MRI.
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Affiliation(s)
- Greg Hong
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Santiago F Cobos
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Tina Khazaee
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - David W Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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Burkhart TA, Hoshino T, Batty LM, Blokker A, Roessler PP, Sidhu R, Drangova M, Holdsworth DW, Petrov I, Degen R, Getgood AM. No Difference in Ligamentous Strain or Knee Kinematics Between Rectangular or Cylindrical Femoral Tunnels During Anatomic ACL Reconstruction With a Bone-Patellar Tendon-Bone Graft. Orthop J Sports Med 2021; 9:23259671211009523. [PMID: 34179204 PMCID: PMC8202273 DOI: 10.1177/23259671211009523] [Citation(s) in RCA: 1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/04/2021] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND As our understanding of anterior cruciate ligament (ACL) anatomy has evolved, surgical techniques to better replicate the native anatomy have been developed. It has been proposed that the introduction of a rectangular socket ACL reconstruction to replace a ribbon-shaped ACL has the potential to improve knee kinematics after ACL reconstruction. PURPOSE To compare a rectangular femoral tunnel (RFT) with a cylindrical femoral tunnel (CFT) in terms of replicating native ACL strain and knee kinematics in a time-zero biomechanical anatomic ACL reconstruction model using a bone-patellar tendon-bone (BTB) graft. STUDY DESIGN Controlled laboratory study. METHODS In total, 16 fresh-frozen, human cadaveric knees were tested in a 5 degrees of freedom, computed tomography-compatible joint motion simulator. Knees were tested with the ACL intact before randomization to RFT or CFT ACL reconstruction using a BTB graft. An anterior translation load and an internal rotation moment were each applied at 0°, 30°, 60°, and 90° of knee flexion. A simulated pivot shift was performed at 0° and 30° of knee flexion. Ligament strain and knee kinematics were assessed using computed tomography facilitated by insertion of zirconium dioxide beads placed within the substance of the native ACL and BTB grafts. RESULTS For the ACL-intact state, there were no differences between groups in terms of ACL strain or knee kinematics. After ACL reconstruction, there were no differences in ACL graft strain when comparing the RFT and CFT groups. At 60° of knee flexion with anterior translation load, there was significantly reduced strain in the reconstructed state ([mean ±standard deviation] CFT native, 2.82 ± 3.54 vs CFT reconstructed, 0.95 ± 2.69; RFT native, 2.77 ± 1.71 vs RFT reconstructed, 1.40 ± 1.76) independent of the femoral tunnel type. In terms of knee kinematics, there were no differences when comparing the RFT and CFT groups. Both reconstructive techniques were mostly effective in restoring native knee kinematics and ligament strain patterns as compared with the native ACL. CONCLUSION In the time-zero biomechanical environment, similar graft strains and knee kinematics were achieved using RFT and CFT BTB ACL reconstructions. Both techniques appeared to be equally effective in restoring kinematics associated with the native ACL state. CLINICAL RELEVANCE These data suggest that in terms of knee kinematics and graft strain, there is no benefit in performing the more technically challenging RFT as compared with a CFT BTB ACL reconstruction.
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Affiliation(s)
- Timothy A. Burkhart
- Mechanical and Materials Engineering, Western University, London, Ontario, Canada
| | - Takashi Hoshino
- Fowler Kennedy Sports Medicine Clinic, Western University, London, Ontario, Canada
| | | | | | | | - Rajeshwar Sidhu
- Fowler Kennedy Sports Medicine Clinic, Western University, London, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, Western University, London, Ontario, Canada
| | | | - Ivailo Petrov
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Ryan Degen
- Fowler Kennedy Sports Medicine Clinic, Western University, London, Ontario, Canada
| | - Alan M. Getgood
- Fowler Kennedy Sports Medicine Clinic, Western University, London, Ontario, Canada
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Burkhart TA, Baha P, Blokker A, Petrov I, Holdsworth DW, Drangova M, Getgood A, Degen RM. Hip capsular strain varies between ligaments dependent on both hip position- and applied rotational force. Knee Surg Sports Traumatol Arthrosc 2020; 28:3393-3399. [PMID: 32363474 DOI: 10.1007/s00167-020-06035-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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: 10/29/2019] [Accepted: 04/27/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To noninvasively characterize the ligament strain in the hip capsule using a novel CT-based imaging technique. METHODS The superior iliofemoral ligament (SIFL), inferior iliofemoral ligament (IIFL), ischiofemoral ligament (IFL) and pubofemoral ligament (PFL) were identified and beaded in seven cadavers. Specimens were mounted on a joint motion simulator within an O-arm CT scanner in - 15°, 0°, 30°, 60°, and 90° of flexion. 3 Nm of internal rotation (IR) and external rotation (ER) were applied and CT scans obtained. Strains were calculated by comparing bead separation in loaded and unloaded conditions. Repeated-measures ANOVA was used to evaluate differences in strain within ligaments between hip positions. RESULTS For the SIFL, strain significantly decreased in IR at 30° (p = 0.045) and 60° (p = 0.043) versus 0°. For ER, there were no significant position-specific changes in strain (n.s.). For the IIFL, strain decreased in IR and increased in ER with no significant position-specific differences. For the IFL, strain increased with IR and decreased with ER with no significant position-specific differences. Finally, in the PFL there was a significant flexion angle-by-load interaction (p < 0.001; ES = 0.566), with peak strains noted at 60˚, however pair-wise comparisons failed to identify significant differences between positions (n.s.). Strain decreased in ER, with no significant position-specific differences. CONCLUSION The SIFL and IIFL limit hip external rotation with greater effect in higher flexion angles, while the IFL and PFL limit hip internal rotation. Following hip arthroscopy, consideration should be given to restricting external rotation as traditional capsulotomies cause injury to the SIFL and IIFL.
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Affiliation(s)
- Timothy A Burkhart
- Department of Mechanical and Materials Engineering, Western University, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada.,Bone and Joint Institute, Western University, London, ON, Canada
| | - Pardis Baha
- Department of Mechanical and Materials Engineering, Western University, London, ON, Canada
| | - Alexandra Blokker
- Department of Mechanical and Materials Engineering, Western University, London, ON, Canada
| | - Ivailo Petrov
- Bone and Joint Institute, Western University, London, ON, Canada.,Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada
| | - David W Holdsworth
- Bone and Joint Institute, Western University, London, ON, Canada.,Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
| | - Maria Drangova
- Bone and Joint Institute, Western University, London, ON, Canada.,Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
| | - Alan Getgood
- Bone and Joint Institute, Western University, London, ON, Canada.,Department of Surgery, Fowler Kennedy Sport Medicine Clinic, Western University, 1151 Richmond Street, London, ON, N6A 3K7, Canada
| | - Ryan M Degen
- Bone and Joint Institute, Western University, London, ON, Canada. .,Department of Surgery, Fowler Kennedy Sport Medicine Clinic, Western University, 1151 Richmond Street, London, ON, N6A 3K7, Canada.
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Gelman D, Skanes AC, Jones DL, Timofeyev M, Bar‐on T, Drangova M. Eliminating the effects of motion during radiofrequency lesion delivery using a novel contact‐force controller. J Cardiovasc Electrophysiol 2019; 30:1652-1662. [DOI: 10.1111/jce.14093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/12/2019] [Accepted: 07/22/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel Gelman
- Robarts Research Institute, Schulich School of Medicine and DentistryThe University of Western OntarioLondon Canada
- School of Biomedical EngineeringThe University of Western OntarioLondon Canada
| | - Allan C. Skanes
- Department of Medicine, Schulich School of Medicine and DentistryThe University of Western OntarioLondon Canada
| | - Douglas L. Jones
- Department of Physiology and Pharmacology, Schulich School of Medicine and DentistryThe University of Western Ontario London Canada
| | | | | | - Maria Drangova
- Robarts Research Institute, Schulich School of Medicine and DentistryThe University of Western OntarioLondon Canada
- School of Biomedical EngineeringThe University of Western OntarioLondon Canada
- Department of Medical Biophysics, Schulich School of Medicine and DentistryThe University of Western OntarioLondon Canada
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Garcia J, Sheitt H, Bristow MS, Lydell C, Howarth AG, Heydari B, Prato FS, Drangova M, Thornhill RE, Nery P, Wilton SB, Skanes A, White JA. Left atrial vortex size and velocity distributions by 4D flow MRI in patients with paroxysmal atrial fibrillation: Associations with age and CHA
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‐VASc risk score. J Magn Reson Imaging 2019; 51:871-884. [DOI: 10.1002/jmri.26876] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 07/03/2019] [Accepted: 07/05/2019] [Indexed: 12/21/2022] Open
Affiliation(s)
- Julio Garcia
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Department of RadiologyUniversity of Calgary Calgary AB Canada
- Stephenson Cardiac Imaging CentreUniversity of Calgary AB Canada
- Libin Cardiovascular Institute of Alberta Calgary AB Canada
- Alberta Children's Hospital Research Institute
| | - Hana Sheitt
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
| | - Michael S. Bristow
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Department of MedicineUniversity of Calgary Calgary AB Canada
| | - Carmen Lydell
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Diagnostic ImagingUniversity of Calgary Calgary AB Canada
| | - Andrew G. Howarth
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Stephenson Cardiac Imaging CentreUniversity of Calgary AB Canada
| | - Bobak Heydari
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Stephenson Cardiac Imaging CentreUniversity of Calgary AB Canada
| | - Frank S. Prato
- Department of Medical BiophysicsSchulich School of Medicine & Dentistry, The University of Western Ontario London Ontario Canada
| | - Maria Drangova
- Department of Medical BiophysicsSchulich School of Medicine & Dentistry, The University of Western Ontario London Ontario Canada
- Imaging Research Laboratories, Robarts Research InstituteSchulich School of Medicine & Dentistry, The University of Western Ontario London Ontario Canada
| | | | - Pablo Nery
- Division of Cardiology, Department of MedicineUniversity of Ottawa Heart Institute Ottawa ON Canada
| | - Stephen B. Wilton
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
| | - Allan Skanes
- Department of MedicineUniversity of Western Ontario London ON Canada
| | - James A. White
- Department of Cardiac SciencesUniversity of Calgary Calgary AB Canada
- Stephenson Cardiac Imaging CentreUniversity of Calgary AB Canada
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Christiansen SD, Liu J, Boffa MB, Drangova M. Simultaneous R 2* and quantitative susceptibility mapping measurement enables differentiation of thrombus hematocrit and age: an in vitro study at 3 T. J Neurointerv Surg 2019; 11:1155-1161. [PMID: 31088940 DOI: 10.1136/neurintsurg-2019-014802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 11/03/2022]
Abstract
BACKGROUND The efficacy of acute ischemic stroke treatment is affected by thrombus composition and age, yet no diagnostic method capable of quantitative thrombus characterization currently exists. This in vitro study evaluates the use of R2* , quantitative susceptibility mapping (QSM), and proton density fat fraction (FF) maps derived from a single gradient echo (GRE) MRI acquisition for characterizing clot of various hematocrit, as well as added calcified and lipidic components, throughout aging. METHODS Two thrombus phantoms containing porcine clots (10-60% hematocrit, one with added calcium or lard) were scanned serially throughout 6 days of aging. Three-dimensional multi-echo GRE imaging was used to generate R2* , QSM, and FF maps, from which mean values for all clots at every time point were obtained. Receiver operating characteristic analysis was used to derive thresholds differentiating acute from chronic clot, and measured R2* and QSM were tested for their ability to estimate clot hematocrit. RESULTS R2* and QSM varied minimally over the first 6 hours of aging (acute), and QSM was found to linearly relate to clot hematocrit. Beyond 6 hours (chronic), R2* and QSM increased considerably over time and hematocrit could be estimated from the R2* /QSM ratio. R2* and QSM thresholds of 22 s-1 and 0.165 ppm differentiated acute from chronic clots with a sensitivity/specificity of 100%/100% and 85%/92%, respectively. QSM and FF maps definitively distinguished calcium and lipid, respectively, from clots of any hematocrit and age. CONCLUSIONS R2* , QSM, and FF from a single multi-echo GRE scan discriminated hematocrit and age, and distinguished calcification and lipid withinin vitro clot.
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Affiliation(s)
- Spencer D Christiansen
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Michael B Boffa
- Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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10
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Johnson PM, Drangova M. Conditional generative adversarial network for 3D rigid-body motion correction in MRI. Magn Reson Med 2019; 82:901-910. [PMID: 31006909 DOI: 10.1002/mrm.27772] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/09/2019] [Accepted: 03/22/2019] [Indexed: 11/10/2022]
Abstract
PURPOSE Subject motion in MRI remains an unsolved problem; motion during image acquisition may cause blurring and artifacts that severely degrade image quality. In this work, we approach motion correction as an image-to-image translation problem, which refers to the approach of training a deep neural network to predict an image in 1 domain from an image in another domain. Specifically, the purpose of this work was to develop and train a conditional generative adversarial network to predict artifact-free brain images from motion-corrupted data. METHODS An open source MRI data set comprising T2 *-weighted, FLASH magnitude, and phase brain images for 53 patients was used to generate complex image data for motion simulation. To simulate rigid motion, rotations and translations were applied to the image data based on randomly generated motion profiles. A conditional generative adversarial network, comprising a generator and discriminator networks, was trained using the motion-corrupted and corresponding ground truth (original) images as training pairs. RESULTS The images predicted by the conditional generative adversarial network have improved image quality compared to the motion-corrupted images. The mean absolute error between the motion-corrupted and ground-truth images of the test set was 16.4% of the image mean value, whereas the mean absolute error between the conditional generative adversarial network-predicted and ground-truth images was 10.8% The network output also demonstrated improved peak SNR and structural similarity index for all test-set images. CONCLUSION The images predicted by the conditional generative adversarial network have quantitatively and qualitatively improved image quality compared to the motion-corrupted images.
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Affiliation(s)
- Patricia M Johnson
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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11
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Johnson PM, Taylor R, Whelan T, Thiessen JD, Anazodo U, Drangova M. Rigid-body motion correction in hybrid PET/MRI using spherical navigator echoes. Phys Med Biol 2019; 64:08NT03. [PMID: 30884475 DOI: 10.1088/1361-6560/ab10b2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Integrated positron emission tomography and magnetic resonance imaging (PET/MRI) is an imaging technology that provides complementary anatomical and functional information for medical diagnostics. Both PET and MRI are highly susceptible to motion artifacts due, in part, to long acquisition times. The simultaneous acquisition of the two modalities presents the opportunity to use MRI navigator techniques for motion correction of both PET and MRI data. For this task, we propose spherical navigator echoes (SNAVs)-3D k-space navigators that can accurately and rapidly measure rigid body motion in all six degrees of freedom. SNAVs were incorporated into turbo FLASH (tfl)-a product fast gradient echo sequence-to create the tfl-SNAV pulse sequence. Acquiring in vivo brain images from a healthy volunteer with both sequences first compared the tfl-SNAV and product tfl sequences. It was observed that incorporation of the SNAVs into the image sequence did not have any detrimental impact on the image quality. The SNAV motion correction technique was evaluated using an anthropomorphic brain phantom. Following a stationary reference image where the tfl-SNAV sequence was acquired along with simultaneous list-mode PET, three identical PET/MRI scans were performed where the phantom was moved several times throughout each acquisition. This motion-up to 11° and 14 mm-resulted in motion artifacts in both PET and MR images. Following SNAV motion correction of the MRI and PET list-mode data, artifact reduction was achieved for both the PET and MR images in all three motion trials. The corrected images have improved image quality and are quantitatively more similar to the ground truth reference images.
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Affiliation(s)
- P M Johnson
- Robarts Research Institute, Western University, London, ON, Canada. Department of Medical Biophysics, Western University, London, ON, Canada
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12
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Elliott CG, Wang J, Walker JT, Michelsons S, Dunmore-Buyze J, Drangova M, Leask A, Hamilton DW. Periostin and CCN2 Scaffolds Promote the Wound Healing Response in the Skin of Diabetic Mice. Tissue Eng Part A 2019; 25:1326-1339. [PMID: 30572781 DOI: 10.1089/ten.tea.2018.0268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
IMPACT STATEMENT Nonhealing skin wounds remain a significant burden on health care systems, with diabetic patients 20 times as likely to undergo a lower extremity amputation due to impaired healing. Novel treatments that suppress the proinflammatory signature and induce the proliferative and remodeling phases are needed clinically. We demonstrate that the addition of periostin and CCN2 in a scaffold form increases closure rates of full-thickness skin wounds in diabetic mice, concomitant with enhanced angiogenesis. Our results demonstrate the efficacy of periostin- and CCN2-containing biomaterials to stimulate wound closure, which could represent a novel method for the treatment of diabetic skin wounds.
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Affiliation(s)
- Christopher G Elliott
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Jiarong Wang
- Division of Vascular Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.,Department of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
| | - John T Walker
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Sarah Michelsons
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Joy Dunmore-Buyze
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Andrew Leask
- Division of Oral Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Douglas W Hamilton
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.,Division of Oral Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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13
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Edey DR, Pollmann SI, Lorusso D, Drangova M, Flemming RL, Holdsworth DW. Extending the dynamic range of biomedical micro-computed tomography for application to geomaterials. J Xray Sci Technol 2019; 27:919-934. [PMID: 31356224 DOI: 10.3233/xst-190511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
BACKGROUND X-ray computed tomography (CT) can non-destructively examine objects by producing three-dimensional images of their internal structure. Although the availability of biomedical micro-CT offers the increased access to scanners, CT images of dense objects are susceptible to artifacts particularly due to beam hardening. OBJECTIVE This study proposes and evaluates a simple semi-empirical correction method for beam hardening and scatter that can be applied to biomedical scanners. METHODS Novel calibration phantoms of varying diameters were designed and built from aluminum and poly[methyl-methacrylate]. They were imaged using two biomedical micro-CT scanners. Absorbance measurements made through different phantom sections were fit to polynomial and inversely exponential functions and used to determine linearization parameters. Corrections based on the linearization equations were applied to the projection data before reconstruction. RESULTS Correction for beam hardening was achieved when applying both scanners with the correction methods to all test objects. Among them, applying polynomial correction method based on the aluminum phantom provided the best improvement. Correction of sample data demonstrated a high agreement of percent-volume composition of dense metallic inclusions between using the Bassikounou meteorite from the micro-CT images (13.7%) and previously published results using the petrographic thin sections (14.6% 8% metal and 6.6% troilite). CONCLUSIONS Semi-empirical linearization of X-ray projection data with custom calibration phantoms allows accurate measurements to be obtained on the radiodense samples after applying the proposed correction method on biomedical micro-CT images.
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Affiliation(s)
- D R Edey
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Earth Sciences, Western University, London, ON, Canada
| | - S I Pollmann
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - D Lorusso
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - M Drangova
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - R L Flemming
- Department of Earth Sciences, Western University, London, ON, Canada
| | - D W Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
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14
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Karim R, Blake LE, Inoue J, Tao Q, Jia S, Housden RJ, Bhagirath P, Duval JL, Varela M, Behar JM, Cadour L, van der Geest RJ, Cochet H, Drangova M, Sermesant M, Razavi R, Aslanidi O, Rajani R, Rhode K. Algorithms for left atrial wall segmentation and thickness - Evaluation on an open-source CT and MRI image database. Med Image Anal 2018; 50:36-53. [PMID: 30208355 PMCID: PMC6218662 DOI: 10.1016/j.media.2018.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 08/14/2018] [Accepted: 08/22/2018] [Indexed: 11/16/2022]
Abstract
Structural changes to the wall of the left atrium are known to occur with conditions that predispose to Atrial fibrillation. Imaging studies have demonstrated that these changes may be detected non-invasively. An important indicator of this structural change is the wall's thickness. Present studies have commonly measured the wall thickness at few discrete locations. Dense measurements with computer algorithms may be possible on cardiac scans of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). The task is challenging as the atrial wall is a thin tissue and the imaging resolution is a limiting factor. It is unclear how accurate algorithms may get and how they compare in this new emerging area. We approached this problem of comparability with the Segmentation of Left Atrial Wall for Thickness (SLAWT) challenge organised in conjunction with MICCAI 2016 conference. This manuscript presents the algorithms that had participated and evaluation strategies for comparing them on the challenge image database that is now open-source. The image database consisted of cardiac CT (n=10) and MRI (n=10) of healthy and diseased subjects. A total of 6 algorithms were evaluated with different metrics, with 3 algorithms in each modality. Segmentation of the wall with algorithms was found to be feasible in both modalities. There was generally a lack of accuracy in the algorithms and inter-rater differences showed that algorithms could do better. Benchmarks were determined and algorithms were ranked to allow future algorithms to be ranked alongside the state-of-the-art techniques presented in this work. A mean atlas was also constructed from both modalities to illustrate the variation in thickness within this small cohort.
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Affiliation(s)
- Rashed Karim
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK.
| | - Lauren-Emma Blake
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Jiro Inoue
- Robarts Research Institute, University of Western Ontario, Canada
| | - Qian Tao
- Leiden University Medical Center, Leiden, The Netherlands
| | - Shuman Jia
- Epione, INRIA Sophia Antipolis, Nice, France
| | - R James Housden
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Pranav Bhagirath
- Department of Cardiology, Haga Teaching Hospital, The Netherlands
| | - Jean-Luc Duval
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Marta Varela
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Jonathan M Behar
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Loïc Cadour
- Epione, INRIA Sophia Antipolis, Nice, France
| | | | | | - Maria Drangova
- Robarts Research Institute, University of Western Ontario, Canada
| | | | - Reza Razavi
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Oleg Aslanidi
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Ronak Rajani
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
| | - Kawal Rhode
- School of Biomedical Engineering & Imaging Sciences, King's College London, UK
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15
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Tse JJ, Dunmore-Buyze J, Drangova M, Holdsworth DW. Dual-energy computed tomography using a gantry-based preclinical cone-beam microcomputed tomography scanner. J Med Imaging (Bellingham) 2018; 5:033503. [PMID: 30155511 PMCID: PMC6103383 DOI: 10.1117/1.jmi.5.3.033503] [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: 12/30/2017] [Accepted: 07/30/2018] [Indexed: 11/14/2022] Open
Abstract
Dual-energy microcomputed tomography (DECT) can provide quantitative information about specific materials of interest, facilitating automated segmentation, and visualization of complex three-dimensional tissues. It is possible to implement DECT on currently available preclinical gantry-based cone-beam micro-CT scanners; however, optimal decomposition image quality requires customized spectral shaping (through added filtration), optimized acquisition protocols, and elimination of misregistration artifacts. We present a method for the fabrication of customized x-ray filters-in both shape and elemental composition-needed for spectral shaping. Fiducial markers, integrated within the sample holder, were used to ensure accurate co-registration between sequential low- and high-energy image volumes. The entire acquisition process was automated through the use of a motorized filter-exchange mechanism. We describe the design, implementation, and evaluation of a DECT system on a gantry-based-preclinical cone-beam micro-CT scanner.
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Affiliation(s)
- Justin J Tse
- Western University, Bone and Joint Institute, Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Western University, Bone and Joint Institute, Departments of Medical Biophysics and Medical Imaging, London, Ontario, Canada
| | - Joy Dunmore-Buyze
- Western University, Bone and Joint Institute, Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Maria Drangova
- Western University, Bone and Joint Institute, Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Western University, Bone and Joint Institute, Departments of Medical Biophysics and Medical Imaging, London, Ontario, Canada
| | - David W Holdsworth
- Western University, Bone and Joint Institute, Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Western University, Bone and Joint Institute, Departments of Medical Biophysics and Medical Imaging, London, Ontario, Canada.,Western University, Bone and Joint Institute, Department of Surgery, London, Ontario, Canada
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16
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Burke AC, Sutherland BG, Telford DE, Morrow MR, Sawyez CG, Edwards JY, Drangova M, Huff MW. Intervention with citrus flavonoids reverses obesity and improves metabolic syndrome and atherosclerosis in obese Ldlr-/- mice. J Lipid Res 2018; 59:1714-1728. [PMID: 30008441 DOI: 10.1194/jlr.m087387] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/12/2018] [Indexed: 12/11/2022] Open
Abstract
Obesity and its associated metabolic dysfunction and cardiovascular disease risk represent a leading cause of adult morbidity worldwide. Currently available pharmacological therapies for obesity have had limited success in reversing existing obesity and metabolic dysregulation. Previous prevention studies demonstrated that the citrus flavonoids, naringenin and nobiletin, protect against obesity and metabolic dysfunction in Ldlr-/- mice fed a high-fat cholesterol-containing (HFHC) diet. However, their effects in an intervention model are unknown. In this report, we show that, in Ldlr-/- mice with diet-induced obesity, citrus flavonoid supplementation to a HFHC diet reversed existing obesity and adipocyte size and number through enhanced energy expenditure and increased hepatic fatty acid oxidation. Caloric intake was unaffected and no evidence of white adipose tissue browning was observed. Reversal of adiposity was accompanied by improvements in hyperlipidemia, insulin sensitivity, hepatic steatosis, and a modest reduction in blood monocytes. Together, this resulted in atherosclerotic lesions that were unchanged in size, but characterized by reduced macrophage content, consistent with a more stable plaque phenotype. These studies further suggest potential therapeutic utility of citrus flavonoids, especially in the context of existing obesity, metabolic dysfunction, and cardiovascular disease.
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Affiliation(s)
- Amy C Burke
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7; Robarts Research Institute, Departments of Biochemistry University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Brian G Sutherland
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Dawn E Telford
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7; Medicine, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Marisa R Morrow
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Cynthia G Sawyez
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7; Medicine, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Jane Y Edwards
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7; Medicine, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Maria Drangova
- Imaging Research Laboratories, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Murray W Huff
- Molecular Medicine University of Western Ontario, London, Ontario, Canada N6A 5B7; Robarts Research Institute, Departments of Biochemistry University of Western Ontario, London, Ontario, Canada N6A 5B7; Medicine, University of Western Ontario, London, Ontario, Canada N6A 5B7.
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17
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Hosseini Z, Matusinec J, Rudko DA, Liu J, Kwan BYM, Salehi F, Sharma M, Kremenchutzky M, Menon RS, Drangova M. Morphology-Specific Discrimination between MS White Matter Lesions and Benign White Matter Hyperintensities Using Ultra-High-Field MRI. AJNR Am J Neuroradiol 2018; 39:1473-1479. [PMID: 29930096 DOI: 10.3174/ajnr.a5705] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/05/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recently published North American Imaging in Multiple Sclerosis guidelines call for derivation of a specific radiologic definition of MS WM lesions and mimics. The purpose of this study was to use SWI and magnetization-prepared FLAIR images for sensitive differentiation of MS from benign WM lesions using the morphologic characteristics of WM lesions. MATERIALS AND METHODS Seventeen patients with relapsing-remitting MS and 18 healthy control subjects were enrolled retrospectively. For each subject, FLAIR and multiecho gradient-echo images were acquired using 7T MR imaging. Optimized postprocessing was used to generate single-slice SWI of cerebral veins. SWI/FLAIR images were registered, and 3 trained readers performed lesion assessment. Morphology, location of lesions, and the time required for assessment were recorded. Analyses were performed on 3 different pools: 1) lesions of >3 mm, 2) nonconfluent lesions of >3 mm, and 3) nonconfluent lesions of >3 mm with no or a single central vein. RESULTS The SWI/FLAIR acquisition and processing protocol enabled effective assessment of central veins and hypointense rims in WM lesions. Assessment of nonconfluent lesions with ≥1 central vein enabled the most specific and sensitive differentiation of patients with MS from controls. A threshold of 67% perivenous WM lesions separated patients with MS from controls with a sensitivity of 94% and specificity of 100%. Lesion assessment took an average of 12 minutes 10 seconds and 4 minutes 33 seconds for patients with MS and control subjects, respectively. CONCLUSIONS Nonconfluent lesions of >3 mm with ≥1 central vein were the most sensitive and specific differentiators between patients with MS and control subjects.
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Affiliation(s)
- Z Hosseini
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.).,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute
| | | | - D A Rudko
- Department of Neurology and Neurosurgery (D.A.R.), McConnell Brain Imaging Centre, Montreal Neurological Institute.,Department of Biomedical Engineering (D.A.R.), McGill University, Montreal, Quebec, Canada
| | - J Liu
- Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute
| | | | - F Salehi
- Medical Imaging (B.Y.M.K., F.S., M.S.)
| | - M Sharma
- Medical Imaging (B.Y.M.K., F.S., M.S.).,Department of Clinical Neurological Sciences (M.S., M.K.), Western University and London Health Sciences Centre, London, Ontario, Canada
| | - M Kremenchutzky
- Department of Clinical Neurological Sciences (M.S., M.K.), Western University and London Health Sciences Centre, London, Ontario, Canada
| | - R S Menon
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.).,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute.,Medical Biophysics (R.S.M., M.D.), Schulich School of Medicine and Dentistry; Western University, London, Ontario, Canada
| | - M Drangova
- From the Biomedical Engineering Graduate Program (Z.H., R.S.M., M.D.) .,Imaging Research Laboratories (Z.H., J.L., R.S.M., M.D.), Robarts Research Institute.,Medical Biophysics (R.S.M., M.D.), Schulich School of Medicine and Dentistry; Western University, London, Ontario, Canada
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18
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Laing J, Moore J, Vassallo R, Bainbridge D, Drangova M, Peters T. Patient-specific cardiac phantom for clinical training and preprocedure surgical planning. J Med Imaging (Bellingham) 2018; 5:021222. [PMID: 29594183 DOI: 10.1117/1.jmi.5.2.021222] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/05/2018] [Indexed: 11/14/2022] Open
Abstract
Minimally invasive mitral valve repair procedures including MitraClip® are becoming increasingly common. For cases of complex or diseased anatomy, clinicians may benefit from using a patient-specific cardiac phantom for training, surgical planning, and the validation of devices or techniques. An imaging compatible cardiac phantom was developed to simulate a MitraClip® procedure. The phantom contained a patient-specific cardiac model manufactured using tissue mimicking materials. To evaluate accuracy, the patient-specific model was imaged using computed tomography (CT), segmented, and the resulting point cloud dataset was compared using absolute distance to the original patient data. The result, when comparing the molded model point cloud to the original dataset, resulted in a maximum Euclidean distance error of 7.7 mm, an average error of 0.98 mm, and a standard deviation of 0.91 mm. The phantom was validated using a MitraClip® device to ensure anatomical features and tools are identifiable under image guidance. Patient-specific cardiac phantoms may allow for surgical complications to be accounted for preoperative planning. The information gained by clinicians involved in planning and performing the procedure should lead to shorter procedural times and better outcomes for patients.
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Affiliation(s)
- Justin Laing
- Western University, Department of Biomedical Engineering, London, Ontario, Canada
| | - John Moore
- Robarts Research Institute, London, Ontario, Canada
| | - Reid Vassallo
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Daniel Bainbridge
- Western University, Department of Anesthesiology, London, Ontario, Canada
| | - Maria Drangova
- Western University, Department of Biomedical Engineering, London, Ontario, Canada.,Robarts Research Institute, London, Ontario, Canada.,Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Terry Peters
- Western University, Department of Biomedical Engineering, London, Ontario, Canada.,Robarts Research Institute, London, Ontario, Canada.,Western University, Department of Medical Biophysics, London, Ontario, Canada
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19
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Cruje C, Dunmore-Buyze J, MacDonald JP, Holdsworth DW, Drangova M, Gillies ER. Polymer Assembly Encapsulation of Lanthanide Nanoparticles as Contrast Agents for In Vivo Micro-CT. Biomacromolecules 2018; 19:896-905. [PMID: 29438616 DOI: 10.1021/acs.biomac.7b01685] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Despite recent technological advancements in microcomputed tomography (micro-CT) and contrast agent development, preclinical contrast agents are still predominantly iodine-based. Higher contrast can be achieved when using elements with higher atomic numbers, such as lanthanides; lanthanides also have X-ray attenuation properties that are ideal for spectral CT. However, the formulation of lanthanide-based contrast agents at the high concentrations required for vascular imaging presents a significant challenge. In this work, we developed an erbium-based contrast agent that meets micro-CT imaging requirements, which include colloidal stability upon redispersion at high concentrations, evasion of rapid renal clearance, and circulation times of tens of minutes in small animals. Through systematic studies with poly(ethylene glycol) (PEG)-poly(propylene glycol), PEG-polycaprolactone, and PEG-poly(l-lactide) (PLA) block copolymers, the amphiphilic block copolymer PEG114-PLA53 was identified to be ideal for encapsulating oleate-coated lanthanide-based nanoparticles for in vivo intravenous administration. We were able to synthesize a contrast agent containing 100 mg/mL of erbium that could be redispersed into colloidally stable particles in saline after lyophilization. Contrast enhancement of over 250 HU was achieved in the blood pool for up to an hour, thereby meeting the requirements of live animal micro-CT.
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20
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Baxter JSH, Hosseini Z, Peters TM, Drangova M. Cyclic Continuous Max-Flow: A Third Paradigm in Generating Local Phase Shift Maps in MRI. IEEE Trans Med Imaging 2018; 37:568-579. [PMID: 29408785 DOI: 10.1109/tmi.2017.2766922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Sensitivity to phase deviations in MRI forms the basis of a variety of techniques, including magnetic susceptibility weighted imaging and chemical shift imaging. Current phase processing techniques fall into two families: those which process the complex image data with magnitude and phase coupled, and phase unwrapping-based techniques that first linearize the phase topology across the image. However, issues, such as low signal and the existence of phase poles, can lead both methods to experience error. Cyclic continuous max-flow (CCMF) phase processing uses primal-dual-variational optimization over a cylindrical manifold, which represent the inherent topology of phase images, increasing its robustness to these issues. CCMF represents a third distinct paradigm in phase processing, being the only technique equipped with the inherent topology of phase. CCMF is robust and efficient with at least comparable accuracy as the prior paradigms.
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21
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Ford NL, McCaig L, Jeklin A, Lewis JF, Veldhuizen RAW, Holdsworth DW, Drangova M. A respiratory-gated micro-CT comparison of respiratory patterns in free-breathing and mechanically ventilated rats. Physiol Rep 2017; 5:5/2/e13074. [PMID: 28100723 PMCID: PMC5269405 DOI: 10.14814/phy2.13074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 11/03/2016] [Revised: 11/14/2016] [Accepted: 11/19/2016] [Indexed: 11/24/2022] Open
Abstract
In this study, we aim to quantify the differences in lung metrics measured in free-breathing and mechanically ventilated rodents using respiratory-gated micro-computed tomography. Healthy male Sprague-Dawley rats were anesthetized with ketamine/xylazine and scanned with a retrospective respiratory gating protocol on a GE Locus Ultra micro-CT scanner. Each animal was scanned while free-breathing, then intubated and mechanically ventilated (MV) and rescanned with a standard ventilation protocol (56 bpm, 8 mL/kg and PEEP of 5 cm H2O) and again with a ventilation protocol that approximates the free-breathing parameters (88 bpm, 2.14 mL/kg and PEEP of 2.5 cm H2O). Images were reconstructed representing inspiration and end expiration with 0.15 mm voxel spacing. Image-based measurements of the lung lengths, airway diameters, lung volume, and air content were compared and used to calculate the functional residual capacity (FRC) and tidal volume. Images acquired during MV appeared darker in the airspaces and the airways appeared larger. Image-based measurements showed an increase in lung volume and air content during standard MV, for both respiratory phases, compared with matched MV and free-breathing. Comparisons of the functional metrics showed an increase in FRC for mechanically ventilated rats, but only the standard MV exhibited a significantly higher tidal volume than free-breathing or matched MV Although standard mechanical ventilation protocols may be useful in promoting consistent respiratory patterns, the amount of air in the lungs is higher than in free-breathing animals. Matching the respiratory patterns with the free-breathing case allowed similar lung morphology and physiology measurements while reducing the variability in the measurements.
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Affiliation(s)
- Nancy L Ford
- Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada .,Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lynda McCaig
- Lawson Health Research Institute, London, Ontario, Canada
| | - Andrew Jeklin
- Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - James F Lewis
- Lawson Health Research Institute, London, Ontario, Canada.,Departments of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Ruud A W Veldhuizen
- Lawson Health Research Institute, London, Ontario, Canada.,Departments of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - David W Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Medical Imaging, University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Medical Imaging, University of Western Ontario, London, Ontario, Canada
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Paquet M, Cerasuolo JO, Thorburn V, Fridman S, Alsubaie R, Lopes RD, Cipriano LE, Salamone P, Melling CWJ, Khan AR, Sedeño L, Fang J, Drangova M, Montero-Odasso M, Mandzia J, Khaw AV, Racosta JM, Paturel J, Samoilov L, Stirling D, Balint B, Jaremek V, Koschinsky ML, Boffa MB, Summers K, Ibañez A, Mrkobrada M, Saposnik G, Kimpinski K, Whitehead SN, Sposato LA. Pathophysiology and Risk of Atrial Fibrillation Detected after Ischemic Stroke (PARADISE): A Translational, Integrated, and Transdisciplinary Approach. J Stroke Cerebrovasc Dis 2017; 27:606-619. [PMID: 29141778 DOI: 10.1016/j.jstrokecerebrovasdis.2017.09.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/22/2017] [Accepted: 09/24/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND It has been hypothesized that ischemic stroke can cause atrial fibrillation. By elucidating the mechanisms of neurogenically mediated paroxysmal atrial fibrillation, novel therapeutic strategies could be developed to prevent atrial fibrillation occurrence and perpetuation after stroke. This could result in fewer recurrent strokes and deaths, a reduction or delay in dementia onset, and in the lessening of the functional, structural, and metabolic consequences of atrial fibrillation on the heart. METHODS The Pathophysiology and Risk of Atrial Fibrillation Detected after Ischemic Stroke (PARADISE) study is an investigator-driven, translational, integrated, and transdisciplinary initiative. It comprises 3 complementary research streams that focus on atrial fibrillation detected after stroke: experimental, clinical, and epidemiological. The experimental stream will assess pre- and poststroke electrocardiographic, autonomic, anatomic (brain and heart pathology), and inflammatory trajectories in an animal model of selective insular cortex ischemic stroke. The clinical stream will prospectively investigate autonomic, inflammatory, and neurocognitive changes among patients diagnosed with atrial fibrillation detected after stroke by employing comprehensive and validated instruments. The epidemiological stream will focus on the demographics, clinical characteristics, and outcomes of atrial fibrillation detected after stroke at the population level by means of the Ontario Stroke Registry, a prospective clinical database that comprises over 23,000 patients with ischemic stroke. CONCLUSIONS PARADISE is a translational research initiative comprising experimental, clinical, and epidemiological research aimed at characterizing clinical features, the pathophysiology, and outcomes of neurogenic atrial fibrillation detected after stroke.
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Affiliation(s)
- Maryse Paquet
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Joshua O Cerasuolo
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Victoria Thorburn
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Sebastian Fridman
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Rasha Alsubaie
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Renato D Lopes
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Lauren E Cipriano
- Department of Epidemiology & Biostatistics, Schulich School of Medicine & Dentistry, Ivey Business School, Western University, London, Ontario, Canada
| | - Paula Salamone
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - C W James Melling
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
| | - Ali R Khan
- Robarts Research Institute, Department of Medical Biophysics & Medical Imaging, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Lucas Sedeño
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Jiming Fang
- Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, Department of Medical Biophysics & Medical Imaging, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Manuel Montero-Odasso
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada; Division of Geriatric Medicine and Dentistry, Department of Medicine, Schulich School of Medicine, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Schulich School of Medicine, Western University, London, Ontario, Canada
| | - Jennifer Mandzia
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Alexander V Khaw
- Department of Clinical Neurological Sciences, London Health Sciences Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Juan M Racosta
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Justin Paturel
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Lucy Samoilov
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Devin Stirling
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Brittany Balint
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Victoria Jaremek
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Marlys L Koschinsky
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Michael B Boffa
- Department of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Kelly Summers
- Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Agustín Ibañez
- Laboratory of Experimental, Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, Buenos Aires, Argentina; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina; Universidad Autónoma del Caribe, Barranquilla, ColombiaCenter for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibáñez, Santiago, Chile; Centre of Excellence in Cognition and its Disorders, Australian Research Council (ACR), Macquarie University, Sydney, New South Wale, Australia
| | - Marko Mrkobrada
- Department of Medicine, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Gustavo Saposnik
- Stroke Outcomes Research Center, Division of Neurology, Department of Medicine, St. Michael's Hospital and Institute of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
| | - Kurt Kimpinski
- Autonomic Disorders Laboratory, Clinical Neurological Sciences Department, Schulich School of Medicine & Dentistry, London Health Sciences Center, Western University, London, ON, Canada
| | - Shawn N Whitehead
- Vulnerable Brain Laboratory, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Luciano A Sposato
- Stroke, Dementia and Heart Disease Laboratory, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Clinical Neurological Sciences at London Health Sciences Centre, Department of Epidemiology and Biostatistics, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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Garcia J, Bristow M, Lydell C, Howarth A, Heydari B, Prato F, Drangova M, Thornhill R, Nery P, Wilton S, Skanes A, White J. LEFT ATRIAL FLOW IN PATIENTS WITH PAROXYSMAL ATRIAL FIBRILLATION USING 4D PHASE CONTRAST MAGNETIC RESONANCE IMAGING. Can J Cardiol 2017. [DOI: 10.1016/j.cjca.2017.07.407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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24
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Modi S, Yee R, Scholl D, Stirrat J, Wong JA, Lydell C, Kotha V, Gula LJ, Skanes AC, Leong-Sit P, McCarty D, Drangova M, White JA. Ventricular pacing site separation by cardiac computed tomography: validation for the prediction of clinical response to cardiac resynchronization therapy. Int J Cardiovasc Imaging 2017; 33:1433-1442. [DOI: 10.1007/s10554-017-1120-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 03/20/2017] [Indexed: 12/01/2022]
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Baxter JSH, Inoue J, Drangova M, Peters TM. Shape complexes: the intersection of label orderings and star convexity constraints in continuous max-flow medical image segmentation. J Med Imaging (Bellingham) 2016; 3:044005. [PMID: 28018937 DOI: 10.1117/1.jmi.3.4.044005] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/28/2016] [Indexed: 11/14/2022] Open
Abstract
Optimization-based segmentation approaches deriving from discrete graph-cuts and continuous max-flow have become increasingly nuanced, allowing for topological and geometric constraints on the resulting segmentation while retaining global optimality. However, these two considerations, topological and geometric, have yet to be combined in a unified manner. The concept of "shape complexes," which combine geodesic star convexity with extendable continuous max-flow solvers, is presented. These shape complexes allow more complicated shapes to be created through the use of multiple labels and super-labels, with geodesic star convexity governed by a topological ordering. These problems can be optimized using extendable continuous max-flow solvers. Previous approaches required computationally expensive coordinate system warping, which are ill-defined and ambiguous in the general case. These shape complexes are demonstrated in a set of synthetic images as well as vessel segmentation in ultrasound, valve segmentation in ultrasound, and atrial wall segmentation from contrast-enhanced CT. Shape complexes represent an extendable tool alongside other continuous max-flow methods that may be suitable for a wide range of medical image segmentation problems.
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Affiliation(s)
- John S H Baxter
- Western University, Robarts Research Institute, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada; Western University, Biomedical Engineering Graduate Program, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada
| | - Jiro Inoue
- Western University , Robarts Research Institute, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada
| | - Maria Drangova
- Western University, Robarts Research Institute, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada; Western University, Biomedical Engineering Graduate Program, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada
| | - Terry M Peters
- Western University, Robarts Research Institute, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada; Western University, Biomedical Engineering Graduate Program, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada
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26
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Liu J, Peters DC, Drangova M. Method of B0 mapping with magnitude-based correction for bipolar two-point Dixon cardiac MRI. Magn Reson Med 2016; 78:1862-1869. [PMID: 27933641 DOI: 10.1002/mrm.26569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 11/14/2016] [Accepted: 11/14/2016] [Indexed: 12/22/2022]
Abstract
PURPOSE The conventional two-point (2pt) Dixon technique explicitly estimates B0 map by performing phase unwrapping. When signal loss, phase singularity, artifacts, or spatially isolated regions corrupt the measured phase images, this unwrapping-based technique will face difficulty. This work aims to improve the reliability of B0 mapping by performing unwrapping error correction. METHOD To detect the unwrapping-caused phase errors, we determined a magnitude-based fat/water mask and used it as reference to identify pixels being mismatched by the phase-based mask, which was derived from the B0-corrected phase term of the Hermitian product between echoes. Then, we corrected the afore-determined phase error on a region-by-region basis. We tested the developed method with nine patients' data, and the results were compared with a well-established region-growing technique. RESULTS By adding the step to correct unwrapping-caused error, we improved the robustness of B0 mapping, resulting in better fat-water separation when compared with the conventional 2pt and the phasor-based region-growing techniques. CONCLUSION We showed the feasibility of B0 mapping with bipolar 2pt human cardiac data. The software is freely available to the scientific community. Magn Reson Med 78:1862-1869, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Dana C Peters
- Department of Radiology and Biomedical Imaging, Yale Medical School, New Haven, Connecticut, USA
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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27
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Gelman D, Skanes AC, Tavallaei MA, Drangova M. Design and Evaluation of a Catheter Contact-Force Controller for Cardiac Ablation Therapy. IEEE Trans Biomed Eng 2016; 63:2301-2307. [DOI: 10.1109/tbme.2016.2525929] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
PURPOSE To develop and evaluate a tool for accurate, reproducible, and programmable motion control of imaging phantoms for use in motion sensitive magnetic resonance imaging (MRI) appli cations. METHODS In this paper, the authors introduce a compact linear motion stage that is made of nonmagnetic material and is actuated with an ultrasonic motor. The stage can be positioned at arbitrary positions and orientations inside the scanner bore to move, push, or pull arbitrary phantoms. Using optical trackers, measuring microscopes, and navigators, the accuracy of the stage in motion control was evaluated. Also, the effect of the stage on image signal-to-noise ratio (SNR), artifacts, and B0 field homogeneity was evaluated. RESULTS The error of the stage in reaching fixed positions was 0.025 ± 0.021 mm. In execution of dynamic motion profiles, the worst-case normalized root mean squared error was below 7% (for frequencies below 0.33 Hz). Experiments demonstrated that the stage did not introduce artifacts nor did it degrade the image SNR. The effect of the stage on the B0 field was less than 2 ppm. CONCLUSIONS The results of the experiments indicate that the proposed system is MRI-compatible and can create reliable and reproducible motion that may be used for validation and assessment of motion related MRI applications.
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Affiliation(s)
- Mohammad Ali Tavallaei
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada and Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario N6A 5B9, Canada
| | - Patricia M Johnson
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada and Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada; Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario N6A 5B9, Canada; and Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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29
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Inoue J, Skanes AC, Gula LJ, Drangova M. Effect of Left Atrial Wall Thickness on Radiofrequency Ablation Success. J Cardiovasc Electrophysiol 2016; 27:1298-1303. [PMID: 27510229 DOI: 10.1111/jce.13065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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: 05/26/2016] [Revised: 06/29/2016] [Accepted: 08/09/2016] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Radiofrequency (RF) ablation in thicker regions of the left atrium (LA) may require increased ablation energy in order to achieve effective transmural lesions. Consequently, many cases of recurrent atrial fibrillation (AF) postablation may be due to thicker-than-normal atrial tissue. The aim of this study was to test the hypotheses that patients with recurrent AF have thicker tissue overall and that electrical reconnection is more likely in regions of thicker tissue. METHODS AND RESULTS Retrospective analysis was performed on 86 CT images acquired preoperatively from a cohort of 119 patients who had undergone RF ablation for AF. Of these, 33 patients experienced recurrence of AF within 1 year of initial treatment and 29 returned for a repeat ablation. For each patient, LA wall thickness (LAWT) was measured from the images in 12 anatomical regions using custom software. Patients with recurrent AF had larger LAWT compared to successfully treated patients (1.6 ± 0.6 mm vs. 1.5 ± 0.5 mm, P < 0.001) and reconnection was found to be at regions of thicker tissue (1.6 ± 0.6 mm, P = 0.038) compared to nonreconnected regions (1.5 ± 0.5 mm). The superior right posterior wall of the LA was significantly related to both recurrence (P = 0.048) and reconnection (P = 0.014). CONCLUSION Increased LAWT has a small but significant effect on postablation recurrence and reconnection. Measures of LAWT may facilitate appropriate dosing of RF energy, but other factors will be critical in transmural lesion formation and ablation success.
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Affiliation(s)
- Jiro Inoue
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Allan C Skanes
- Division of Cardiology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada
| | - Lorne J Gula
- Division of Cardiology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
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30
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Hosseini Z, Liu J, Solovey I, Menon RS, Drangova M. Susceptibility-weighted imaging using inter-echo-variance channel combination for improved contrast at 7 tesla. J Magn Reson Imaging 2016; 45:1113-1124. [PMID: 27527348 DOI: 10.1002/jmri.25409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/20/2016] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To implement and optimize a new approach for susceptibility-weighted image (SWI) generation from multi-echo multi-channel image data and compare its performance against optimized traditional SWI pipelines. MATERIALS AND METHODS Five healthy volunteers were imaged at 7 Tesla. The inter-echo-variance (IEV) channel combination, which uses the variance of the local frequency shift at multiple echo times as a weighting factor during channel combination, was used to calculate multi-echo local phase shift maps. Linear phase masks were combined with the magnitude to generate IEV-SWI. The performance of the IEV-SWI pipeline was compared with that of two accepted SWI pipelines-channel combination followed by (i) Homodyne filtering (HPH-SWI) and (ii) unwrapping and high-pass filtering (SVD-SWI). The filtering steps of each pipeline were optimized. Contrast-to-noise ratio was used as the comparison metric. Qualitative assessment of artifact and vessel conspicuity was performed and processing time of pipelines was evaluated. RESULTS The optimized IEV-SWI pipeline (σ = 7 mm) resulted in continuous vessel visibility throughout the brain. IEV-SWI had significantly higher contrast compared with HPH-SWI and SVD-SWI (P < 0.001, Friedman nonparametric test). Residual background fields and phase wraps in HPH-SWI and SVD-SWI corrupted the vessel signal and/or generated vessel-mimicking artifact. Optimized implementation of the IEV-SWI pipeline processed a six-echo 16-channel dataset in under 10 min. CONCLUSION IEV-SWI benefits from channel-by-channel processing of phase data and results in high contrast images with an optimal balance between contrast and background noise removal, thereby presenting evidence of importance of the order in which postprocessing techniques are applied for multi-channel SWI generation. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:1113-1124.
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Affiliation(s)
- Zahra Hosseini
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Igor Solovey
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Ravi S Menon
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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Johnson PM, Liu J, Wade T, Tavallaei MA, Drangova M. Retrospective 3D motion correction using spherical navigator echoes. Magn Reson Imaging 2016; 34:1274-1282. [PMID: 27451402 DOI: 10.1016/j.mri.2016.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/06/2016] [Accepted: 06/26/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE To develop and evaluate a rapid spherical navigator echo (SNAV) motion correction technique, then apply it for retrospective correction of brain images. METHODS The pre-rotated, template matching SNAV method (preRot-SNAV) was developed in combination with a novel hybrid baseline strategy, which includes acquired and interpolated templates. Specifically, the SNAV templates are only rotated around X- and Y-axis; for each rotated SNAV, simulated baseline templates that mimic object rotation about the Z-axis were interpolated. The new method was first evaluated with phantom experiments. Then, a customized SNAV-interleaved gradient echo sequence was used to image three volunteers performing directed head motion. The SNAV motion measurements were used to retrospectively correct the brain images. Experiments were performed using a 3.0T whole-body MRI scanner and both single and 8-channel head coils. RESULTS Phantom rotations and translations measured using the hybrid baselines agreed to within 0.9° and 1mm compared to those measured with the original preRot-SNAV method. Retrospective motion correction of in vivo images using the hybrid preRot-SNAV effectively corrected for head rotation up to 4° and 4mm. CONCLUSIONS The presented hybrid approach enables the acquisition of pre-rotated baseline templates in as little as 2.5s, and results in accurate measurement of rotations and translations. Retrospective 3D motion correction successfully reduced motion artifacts in vivo.
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Affiliation(s)
- Patricia M Johnson
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Trevor Wade
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Mohammad Ali Tavallaei
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada.
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32
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Patrick J, Tavallaei M, Thompson R, Stodilka R, Drangova M, Gaede S. SU-F-I-58: Image Quality Comparisons of Different Motion Magnitudes and TR Values in MR-PET. Med Phys 2016. [DOI: 10.1118/1.4955886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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33
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Satriano A, Kandalam V, Mikami Y, Guron N, Medwid H, Heydari B, Merchant N, Howarth AG, Lydell C, Whitman TA, Drangova M, Yee R, White JA. Multiplanar 4D strain analysis with spatial mapping to 3D LGE quantification: relationships in chronic Ischemic Cardiomyopathy. J Cardiovasc Magn Reson 2015. [PMCID: PMC4328862 DOI: 10.1186/1532-429x-17-s1-p33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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34
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Tavallaei MA, Gelman D, Lavdas MK, Skanes AC, Jones DL, Bax JS, Drangova M. Design, development and evaluation of a compact telerobotic catheter navigation system. Int J Med Robot 2015; 12:442-52. [PMID: 26525639 DOI: 10.1002/rcs.1711] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/26/2015] [Accepted: 09/27/2015] [Indexed: 11/06/2022]
Abstract
BACKGROUND Remote catheter navigation systems protect interventionalists from scattered ionizing radiation. However, these systems typically require specialized catheters and extensive operator training. METHODS A new compact and sterilizable telerobotic system is described, which allows remote navigation of conventional tip-steerable catheters, with three degrees of freedom, using an interface that takes advantage of the interventionalist's existing dexterity skills. The performance of the system is evaluated ex vivo and in vivo for remote catheter navigation and ablation delivery. RESULTS The system has absolute errors of 0.1 ± 0.1 mm and 7 ± 6° over 100 mm of axial motion and 360° of catheter rotation, respectively. In vivo experiments proved the safety of the proposed telerobotic system and demonstrated the feasibility of remote navigation and delivery of ablation. CONCLUSION The proposed telerobotic system allows the interventionalist to use conventional steerable catheters; while maintaining a safe distance from the radiation source, he/she can remotely navigate the catheter and deliver ablation lesions. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Mohammad Ali Tavallaei
- Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Biomedical Engineering Graduate Programme, University of Western Ontario, London, ON, Canada
| | - Daniel Gelman
- Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Biomedical Engineering Graduate Programme, University of Western Ontario, London, ON, Canada
| | - Michael Konstantine Lavdas
- Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Mechatronics Engineering Programme, University of Western Ontario, London, ON, Canada
| | - Allan C Skanes
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Douglas L Jones
- Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Canadian Surgical Technologies and Advanced Robotics, London Health Sciences Centre, University Hospital, London, ON, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Jeffrey S Bax
- Centre of Imaging Technology Commercialization (CIMTEC), London, ON, Canada
| | - Maria Drangova
- Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Biomedical Engineering Graduate Programme, University of Western Ontario, London, ON, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
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Stirrat J, Joncas SX, Salerno M, Drangova M, White J. Influence of phase correction of late gadolinium enhancement images on scar signal quantification in patients with ischemic and non-ischemic cardiomyopathy. J Cardiovasc Magn Reson 2015; 17:66. [PMID: 26248535 PMCID: PMC4528363 DOI: 10.1186/s12968-015-0163-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/24/2015] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Myocardial fibrosis imaging using late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) has been validated as a quantitative predictive marker for response to medical, surgical, and device therapy. To date, all such studies have examined conventional, non-phase corrected magnitude images. However, contemporary practice has rapdily adopted phase-corrected image reconstruction. We sought to investigate the existence of any systematic bias between threshold-based scar quantification performed on conventional magnitude inversion recovery (MIR) and matched phase sensitive inversion recovery (PSIR) images. METHODS In 80 patients with confirmed ischemic (N = 40), or non-ischemic (n = 40) myocardial fibrosis, and also in a healthy control cohort (N = 40) without fibrosis, myocardial late enhancement was quantified using a Signal Threshold Versus Reference Myocardium technique (STRM) at ≥2, ≥3, and ≥5 SD threshold, and also using the Full Width at Half Maximal (FWHM) technique. This was performed on both MIR and PSIR images and values compared using linear regression and Bland-Altman analyses. RESULTS Linear regression analysis demonstrated excellent correlation for scar volumes between MIR and PSIR images at all three STRM signal thresholds for the ischemic (N = 40, r = 0.96, 0.95, 0.88 at 2, 3, and 5 SD, p < 0.0001 for all regressions), and non ischemic (N = 40, r = 0.86, 0.89, 0.90 at 2, 3, and 5 SD, p < 0.0001 for all regressions) cohorts. FWHM analysis demonstrated good correlation in the ischemic population (N = 40, r = 0.83, p < 0.0001). Bland-Altman analysis demonstrated a systematic bias with MIR images showing higher values than PSIR for ischemic (3.3 %, 3.9 % and 4.9 % at 2, 3, and 5 SD, respectively), and non-ischemic (9.7 %, 7.4 % and 4.1 % at ≥2, ≥3, and ≥5 SD thresholds, respectively) cohorts. Background myocardial signal measured in the control population demonstrated a similar bias of 4.4 %, 2.6 % and 0.7 % of the LV volume at 2, 3 and 5 SD thresholds, respectively. The bias observed using FWHM analysis was -6.9 %. CONCLUSIONS Scar quantification using phase corrected (PSIR) images achieves values highly correlated to those obtained on non-corrected (MIR) images. However, a systematic bias exists that appears exaggerated in non-ischemic cohorts. Such bias should be considered when comparing or translating knowledge between MIR- and PSIR-based imaging.
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Affiliation(s)
- John Stirrat
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
| | - Sebastien Xavier Joncas
- Division of Cardiology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
- Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
| | - Michael Salerno
- Departments of Medicine, Radiology, and Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
| | - Maria Drangova
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
- Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
| | - James White
- Division of Cardiology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
- Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
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Assini JM, Mulvihill EE, Burke AC, Sutherland BG, Telford DE, Chhoker SS, Sawyez CG, Drangova M, Adams AC, Kharitonenkov A, Pin CL, Huff MW. Naringenin prevents obesity, hepatic steatosis, and glucose intolerance in male mice independent of fibroblast growth factor 21. Endocrinology 2015; 156:2087-102. [PMID: 25774553 DOI: 10.1210/en.2014-2003] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The molecular mechanisms and metabolic pathways whereby the citrus flavonoid, naringenin, reduces dyslipidemia and improves glucose tolerance were investigated in C57BL6/J wild-type mice and fibroblast growth factor 21 (FGF21) null (Fgf21(-/-)) mice. FGF21 regulates energy homeostasis and the metabolic adaptation to fasting. One avenue of this regulation is through induction of peroxisome proliferator-activated receptor-γ coactivator-1α (Pgc1a), a regulator of hepatic fatty acid oxidation and ketogenesis. Because naringenin is a potent activator of hepatic FA oxidation, we hypothesized that induction of FGF21 might be an integral part of naringenin's mechanism of action. Furthermore, we predicted that FGF21 deficiency would potentiate high-fat diet (HFD)-induced metabolic dysregulation and compromise metabolic protection by naringenin. The absence of FGF21 exacerbated the response to a HFD. Interestingly, naringenin supplementation to the HFD robustly prevented obesity in both genotypes. Gene expression analysis suggested that naringenin was not primarily targeting fatty acid metabolism in white adipose tissue. Naringenin corrected hepatic triglyceride concentrations and normalized hepatic expression of Pgc1a, Cpt1a, and Srebf1c in both wild-type and Fgf21(-/-) mice. HFD-fed Fgf21(-/-) mice displayed greater muscle triglyceride deposition, hyperinsulinemia, and impaired glucose tolerance as compared with wild-type mice, confirming the role of FGF21 in insulin sensitivity; however, naringenin supplementation improved these metabolic parameters in both genotypes. We conclude that FGF21 deficiency exacerbates HFD-induced obesity, hepatic steatosis, and insulin resistance. Furthermore, FGF21 is not required for naringenin to protect mice from HFD-induced metabolic dysregulation. Collectively these studies support the concept that naringenin has potent lipid-lowering effects and may act as an insulin sensitizer in vivo.
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Affiliation(s)
- Julia M Assini
- Department of Vascular Biology (J.M.A., E.E.M., A.C.B., B.G.S., D.E.T., S.S.C., C.G.S., M.W.H.) and Imaging Research Laboratories (M.D.), Robarts Research Institute, London, Ontario, Canada N6A 5B7; Children's Health Research Institute and Departments of Paediatrics, Physiology and Pharmacology, and Oncology (C.L.P.); Departments of Biochemistry (J.M.A., E.E.M., A.C.B., S.S.C., M.W.H.), Medical Biophysics (M.D.) and Medicine (D.E.T., C.G.S., M.W.H.), The University of Western Ontario, London, Ontario, Canada N6A 5B7; and Lilly Research Laboratories (A.C.A., A.K.), Division of Eli Lilly and Company, Indianapolis, Indiana 46285
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Bondoc AB, Detombe S, Dunmore-Buyze J, Gutpell KM, Liu L, Kaszuba A, Han S, McGirr R, Hadway J, Drangova M, Hoffman LM. Application of 3-d echocardiography and gated micro-computed tomography to assess cardiomyopathy in a mouse model of duchenne muscular dystrophy. Ultrasound Med Biol 2014; 40:2857-2867. [PMID: 25308942 DOI: 10.1016/j.ultrasmedbio.2014.07.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 04/15/2014] [Accepted: 07/27/2014] [Indexed: 06/04/2023]
Abstract
The purpose of this study was to measure changes in cardiac function as cardiomyopathy progresses in a mouse model of Duchenne muscular dystrophy using 3-D ECG-gated echocardiography. This study is the first to correlate cardiac volumes acquired using 3-D echocardiography with those acquired using retrospectively gated micro-computed tomography (CT). Both were further compared with standard M-mode echocardiography and histologic analyses. We found that although each modality measures a decrease in cardiac function as disease progresses in mdx/utrn(-/-) mice (n = 5) compared with healthy C57BL/6 mice (n = 8), 3-D echocardiography has higher agreement with gold-standard measurements acquired by gated micro-CT, with little standard deviation between measurements. M-Mode echocardiography measurements, in comparison, exhibit considerably greater variability and user bias. Given the radiation dose associated with micro-CT and the geometric assumptions made in M-mode echocardiography to calculate ventricular volume, we suggest that use of 3-D echocardiography has important advantages that may allow for the measurement of early disease changes that occur before overt cardiomyopathy.
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Affiliation(s)
- Andrew B Bondoc
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Sarah Detombe
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Joy Dunmore-Buyze
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Kelly M Gutpell
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; Department of Anatomy & Cell Biology, Western University, London, Ontario, Canada
| | - Linshan Liu
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Amanda Kaszuba
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada
| | - Seongryoung Han
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada
| | - Rebecca McGirr
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada
| | - Jennifer Hadway
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Maria Drangova
- Department of Medical Biophysics, Western University, London, Ontario, Canada; Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Lisa M Hoffman
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Anatomy & Cell Biology, Western University, London, Ontario, Canada.
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Liu J, Drangova M. Method for B0 off-resonance mapping by non-iterative correction of phase-errors (B0-NICE). Magn Reson Med 2014; 74:1177-88. [PMID: 25351504 DOI: 10.1002/mrm.25497] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 09/23/2014] [Accepted: 09/25/2014] [Indexed: 12/22/2022]
Abstract
PURPOSE To develop and evaluate a multiecho phase-unwrapping-based B0 mapping method. METHODS The proposed method estimates a B0 map by Non-Iterative Correction of phase-Errors (B0-NICE). The B0-NICE method generates an initial B0 map from a "pseudo in-phase" data set by introducing a bias frequency shift to the multipeak fat model, followed by correcting the phase errors using both phase and magnitude information. The performance of the B0-NICE method was evaluated with all data cases from the 2012 ISMRM Challenge. RESULTS The B0 field estimates from B0-NICE were compared with those generated by GlObally Optimal Surface Estimation (GOOSE). In the presence of large B0 inhomogeneity, the B0-NICE method was able to generate more realistic B0 maps from multiecho data, compared with GOOSE. Accurate estimation of fat-fraction (FF) map was also achieved using the proposed algorithm. CONCLUSION The primary finding of the present study is that accurate FF and B0 maps are achievable if magnitude data is processed independently and used to correct phase errors existing in B0 maps generated by phase unwrapping. The B0-NICE software is freely available to the scientific community.
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Affiliation(s)
- Junmin Liu
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
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Laksman Z, Yee R, Stirrat J, Gula LJ, Skanes AC, Leong-Sit P, Manlucu J, McCarty D, Turkistani Y, Scholl D, Rajchl M, Goela A, Islam A, Thompson RT, Drangova M, White JA. Model-based navigation of left and right ventricular leads to optimal targets for cardiac resynchronization therapy: a single-center feasibility study. Circ Arrhythm Electrophysiol 2014; 7:1040-7. [PMID: 25221334 DOI: 10.1161/circep.114.001729] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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] [Indexed: 12/18/2022]
Abstract
BACKGROUND Left ventricular (LV) and right ventricular pacing site characteristics have been shown to influence response to cardiac resynchronization therapy (CRT). This study aimed to determine the clinical feasibility of image-guided lead delivery using a 3-dimensional navigational model displaying both LV and right ventricular (RV) pacing targets. Serial echocardiographic measures of clinical response and procedural metrics were evaluated. METHODS AND RESULTS Thirty-one consecutive patients underwent preimplant cardiac MRI with the generation of a 3-dimensional navigational model depicting optimal segmental targets for LV and RV leads. Lead delivery was guided by the model in matched views to intraprocedural fluoroscopy. Blinded assessment of final lead tip location was performed from postprocedural cardiac computed tomography. Clinical and LV remodeling response criteria were assessed at baseline, 3 months, and 6 months using a 6-minute hall walk, quality of life questionnaire, and echocardiography. Mean age and LV ejection fraction was 66 ± 8 years and 26 ± 8%, respectively. LV leads were successfully delivered to a target or adjacent segment in 30 of 31 patients (97%), 68% being nonposterolateral. RV leads were delivered to a target or adjacent segment in 30 of 31 patients (97%), 26% being nonapical. Twenty-three patients (74%) met standard criteria for response (LV end-systolic volume reduction ≥ 15%), 18 patients (58%) for super-response (LV end-systolic volume reduction ≥ 30%). LV ejection fraction improved at 6 months (31 ± 8 versus 26 ± 8%, P=0.04). CONCLUSIONS This study demonstrates clinical feasibility of dual cardiac resynchronization therapy lead delivery to optimal targets using a 3-dimensional navigational model. High procedural success, acceptable procedural times, and a low rate of early procedural complications were observed. CLINICAL TRIAL REGISTRATION URL http://www.clinicaltrials.gov. Unique identifier: NCT01640769.
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Affiliation(s)
- Zachary Laksman
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Raymond Yee
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - John Stirrat
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Lorne J Gula
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Allan C Skanes
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Peter Leong-Sit
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Jamie Manlucu
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - David McCarty
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Yosra Turkistani
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - David Scholl
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Martin Rajchl
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Aashish Goela
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Ali Islam
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - R Terry Thompson
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - Maria Drangova
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.)
| | - James A White
- From the Division of Cardiology, Department of Medicine (Z.L., R.Y., L.J.G., A.C.S., P.L.-S., J.M., D.M.C., Y.T., J.A.W.), Imaging Laboratories, Robarts Research Institute (J.S., D.S., M.R., M.D.), and Lawson Health Research Institute (R.T.T.), University of Western Ontario, London, Ontario; Department of Medical Imaging, Schulich School of Medicine and Dentistry, London, Ontario (A.G., A.I., R.T.T., M.D.); and Department of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada (J.A.W.).
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Armstrong ZB, Boughner DR, Carruthers CP, Drangova M, Rogers KA. Effects of an Angiotensin II Type 1 Receptor Blocker on Aortic Valve Sclerosis in a Preclinical Model. Can J Cardiol 2014; 30:1096-103. [DOI: 10.1016/j.cjca.2013.12.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 12/03/2013] [Accepted: 12/21/2013] [Indexed: 10/25/2022] Open
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Burke AC, Sutherland BG, Sawyez CG, Telford DE, Umoh J, Drangova M, Huff MW. Abstract 67: Intervention With Citrus Flavonoids Reverses Existing Metabolic Disorders and Attenuates the Progression of Advanced Atherosclerosis in High Fat--Fed LDLr-/- Mice. Arterioscler Thromb Vasc Biol 2014. [DOI: 10.1161/atvb.34.suppl_1.67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous studies demonstrated that addition of the citrus flavonoids naringenin or nobiletin to a high-fat diet prevented the development of many disorders linked to the metabolic syndrome. In the present study, we assessed the ability of intervention with nobiletin or naringenin to reverse pre-established obesity, insulin resistance, hepatic steatosis, dyslipidemia and attenuate atherogenesis. Ldlr-/- mice were fed chow or a high-fat, cholesterol-containing (HFHC) diet for 12 weeks. For an additional 12 weeks, the HFHC-fed mice: (1) continued on the HFHC diet or were transferred to (2) chow, (3) HFHC + 3% naringenin, or (4) HFHC + 0.3% nobiletin. Following rapid weight gain during HFHC-induction, intervention with naringenin or nobiletin stimulated weight loss, while maintaining caloric intake. Micro-CT imaging revealed flavonoid intervention reversed adipose tissue accumulation by 40-60% in both subcutaneous and visceral depots. At 12 weeks, the HFHC-fed mice were hyperinsulinemic (6-fold), which was accompanied by increased fasting plasma glucose. Intervention with either flavonoid normalized plasma insulin and glucose and corrected impaired insulin and glucose tolerance. The HFHC diet increased cholesterol within VLDL (10-fold) and LDL (6-fold), which was reduced (~50%) by either naringenin or nobiletin intervention. HFHC-induction significantly increased hepatic steatosis. Flavonoid intervention reduced hepatic cholesterol (>50%) and triglyceride (~20%) via increased expression of Pgc1a and Cpt1a and reduced expression of Srebp1c. HFHC-induction increased atherosclerotic lesion area (13-fold), which was increased a further 2.5-fold at 24 weeks. Flavonoid intervention modestly retarded lesion size progression (16-20%). As well, intervention with naringenin or nobiletin slowed the accumulation of aortic cholesterol (~30-45%) and reduced lesional necrotic area (~25%), suggesting improved lesion morphology. These studies demonstrate in mice with pre-existing metabolic dysregulation and atherosclerosis that intervention with naringenin or nobiletin reverses obesity, dyslipidemia, hepatic steatosis and insulin resistance, and modestly attenuates the progression of advanced atherosclerosis.
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Affiliation(s)
- Amy C Burke
- Biochemistry, The Univ of Western Ontario, London, Canada
| | | | | | | | - Joseph Umoh
- Imaging Rsch Laboratories, Robarts Rsch Institute, London, Canada
| | - Maria Drangova
- Imaging Rsch Laboratories, Robarts Rsch Institute, London, Canada
| | - Murray W Huff
- Medicine, The Univ of Western Ontario, London, Canada
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Dunmore-Buyze PJ, Tate E, Xiang FL, Detombe SA, Nong Z, Pickering JG, Drangova M. Three-dimensional imaging of the mouse heart and vasculature using micro-CT and whole-body perfusion of iodine or phosphotungstic acid. Contrast Media Mol Imaging 2014; 9:383-90. [PMID: 24764151 DOI: 10.1002/cmmi.1588] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 12/20/2022]
Abstract
Recent studies have investigated histological staining compounds as micro-computed tomography (micro-CT) contrast agents, delivered by soaking tissue specimens in stain and relying on passive diffusion for agent uptake. This study describes a perfusion approach using iodine or phosphotungstic acid (PTA) stains, delivered to an intact mouse, to capitalize on the microvasculature as a delivery conduit for parenchymal staining and direct contact for staining artery walls. Twelve C57BL/6 mice, arterially perfused with either 25% Lugol's solution or 5% PTA solution were scanned intact and reconstructed with 26 µm isotropic voxels. The animals were fixed and the heart and surrounding vessels were excised, embedded and scanned; isolated heart images were reconstructed with 13 µm isotropic voxels. Myocardial enhancement and artery diameters were measured. Both stains successfully enhanced the myocardium and vessel walls. Interestingly, Lugol's solution provided a significantly higher enhancement of the myocardium than PTA [2502 ± 437 vs 656 ± 178 Hounsfield units (HU); p < 0.0001], delineating myofiber architecture and orientation. There was no significant difference in vessel wall enhancement (Lugol's, 1036 ± 635 HU; PTA, 738 ± 124 HU; p = 0.29), but coronary arteries were more effectively segmented from the PTA-stained hearts, enabling segmented imaging of fifth- order coronary artery branches. The combination of whole mouse perfusion delivery and use of heavy metal-containing stains affords high-resolution imaging of the mouse heart and vasculature by micro-CT. The differential imaging patterns of Lugol's- and PTA-stained tissues reveals new opportunities for micro-analyses of cardiac and vascular tissues.
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Affiliation(s)
- P Joy Dunmore-Buyze
- Robarts Research Institute, The University of Western Ontario, London, ON, Canada
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43
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Liu J, Rudko DA, Gati JS, Menon RS, Drangova M. Inter-echo variance as a weighting factor for multi-channel combination in multi-echo acquisition for local frequency shift mapping. Magn Reson Med 2014; 73:1654-61. [DOI: 10.1002/mrm.25247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/26/2014] [Accepted: 03/18/2014] [Indexed: 01/26/2023]
Affiliation(s)
- Junmin Liu
- Imaging Research Laboratories; Robarts Research Institute, University of Western Ontario; London Canada
| | - David A. Rudko
- Imaging Research Laboratories; Robarts Research Institute, University of Western Ontario; London Canada
- Department of Physics and Astronomy; University of Western Ontario; London Canada
| | - Joseph S. Gati
- Imaging Research Laboratories; Robarts Research Institute, University of Western Ontario; London Canada
| | - Ravi S. Menon
- Imaging Research Laboratories; Robarts Research Institute, University of Western Ontario; London Canada
- Department of Physics and Astronomy; University of Western Ontario; London Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry; University of Western Ontario; London Canada
| | - Maria Drangova
- Imaging Research Laboratories; Robarts Research Institute, University of Western Ontario; London Canada
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry; University of Western Ontario; London Canada
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44
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Jolly US, Soliman A, McKenzie C, Peters T, Stirrat J, Nevis I, Brymer M, Joy T, Drangova M, White JA. Intra-thoracic fat volume is associated with myocardial infarction in patients with metabolic syndrome. J Cardiovasc Magn Reson 2013; 15:77. [PMID: 24020829 PMCID: PMC3847137 DOI: 10.1186/1532-429x-15-77] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/22/2013] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Visceral adiposity is increased in those with Metabolic Syndrome (MetS) and atherosclerotic disease burden. In this study we evaluate for associations between intra-thoracic fat volume (ITFV) and myocardial infarction (MI) in patients with MetS. METHODS Ninety-four patients with MetS, MI or both were identified from a cardiovascular CMR clinical registry. MetS was defined in accordance to published guidelines; where-as MI was defined as the presence of subendocardial-based injury on late gadolinium enhancement imaging in a coronary vascular distribution. A healthy control group was also obtained from the same registry. Patients were selected into the following groups: MetS+/MI- (N = 32), MetS-/MI + (N = 30), MetS+/MI + (N = 32), MetS-/MI- (N = 16). ITFV quantification was performed using signal threshold analysis of sequential sagittal CMR datasets (HASTE) and indexed to body mass index. RESULTS The mean age of the population was 59.8 ± 12.5 years. MetS+ patients (N=64) demonstrated a significantly higher indexed ITFV compared to MetS- patients (p = 0.05). Patients in respective MetS-/MI-, MetS+/MI-, MetS-/MI+, and MetS+/MI + study groups demonstrated a progressive elevation in the indexed ITFV (22.3 ± 10.6, 28.6 ± 12.6, 30.6 ± 12.3, and 35.2 ± 1.4 ml/kg/m(2), (p = 0.002)). Among MetS+ patients those with MI showed a significantly higher indexed ITFV compared to those without MI (p = 0.02). CONCLUSIONS ITFV is elevated in patients with MetS and incrementally elevated among those with evidence of prior ischemic myocardial injury. Accordingly, the quantification of ITFV may be a valuable marker of myocardial infarction risk among patients with MetS and warrants further investigation.
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Affiliation(s)
- Umjeet S Jolly
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Abraam Soliman
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
- Biomedical Engineering, University of Western Ontario, London, Ontario, Canada
| | - Charles McKenzie
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Terry Peters
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - John Stirrat
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Immaculate Nevis
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Matthew Brymer
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Tisha Joy
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - James A White
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
- Cardiovascular MRI Clinical Research (CMCR) Program, London Health Sciences Center, 339 Windermere Road, London, Ontario N6A 5A5, Canada
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45
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Jensen MD, Hrinivich WT, Jung JA, Holdsworth DW, Drangova M, Chen J, Wong E. Implementation and commissioning of an integrated micro-CT/RT system with computerized independent jaw collimation. Med Phys 2013; 40:081706. [DOI: 10.1118/1.4812422] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wong JA, Yee R, Stirrat J, Scholl D, Krahn AD, Gula LJ, Skanes AC, Leong-Sit P, Klein GJ, McCarty D, Fine N, Goela A, Islam A, Thompson T, Drangova M, White JA. Influence of pacing site characteristics on response to cardiac resynchronization therapy. Circ Cardiovasc Imaging 2013; 6:542-50. [PMID: 23741053 DOI: 10.1161/circimaging.111.000146] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [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] [Indexed: 12/19/2022]
Abstract
BACKGROUND Transmural scar occupying left ventricular (LV) pacing regions has been associated with reduced response to cardiac resynchronization therapy (CRT). However, spatial influences of lead tip delivery relative to scar at both pacing sites remain poorly explored. This study evaluated scar distribution relative to LV and right ventricular (RV) lead tip placement through coregistration of late gadolinium enhancement MRI and cardiac computed tomographic (CT) findings. Influences on CRT response were assessed by serial echocardiography. METHODS AND RESULTS Sixty patients receiving CRT underwent preimplant late gadolinium enhancement MRI, postimplant cardiac CT, and serial echocardiography. Blinded segmental evaluations of mechanical delay, percentage scar burden, and lead tip location were performed. Response to CRT was defined as a reduction in LV end-systolic volume ≥15% at 6 months. The mean age and LV ejection fraction were 64±9 years and 25±7%, respectively. Mean scar volume was higher among CRT nonresponders for both the LV (23±23% versus 8±14% [P=0.01]) and RV pacing regions (40±32% versus 24±30% [P=0.04]). Significant pacing region scar was identified in 13% of LV pacing regions and 37% of RV pacing regions. Absence of scar in both regions was associated with an 81% response rate compared with 55%, 25%, and 0%, respectively, when the RV, LV, or both pacing regions contained scar. LV pacing region dyssynchrony was not predictive of response. CONCLUSIONS Myocardial scar occupying the LV pacing region is associated with nonresponse to CRT. Scar occupying the RV pacing region is encountered at higher frequency and seems to provide a more intermediate influence on CRT response.
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Affiliation(s)
- Jorge A Wong
- Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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Armitage SEJ, Pollmann SI, Detombe SA, Drangova M. Least-error projection sorting to optimize retrospectively gated cardiac micro-CT of free-breathing mice. Med Phys 2013; 39:1452-61. [PMID: 22380378 DOI: 10.1118/1.3681949] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop and characterize a technique for optimizing image quality by eliminating streaking artifacts in retrospectively gated microcomputed tomography (micro-CT) images of mice caused by insufficient and irregular angular sampling. METHODS A least-error sorting technique was developed to minimize streak artifacts in retrospectively gated cardiac micro-CT images. To ensure complete filling of projection space, for each angular position, the projection acquired closest to the desired cardiac phase is used to reconstruct a volumetric image. An acrylic slanted-edge phantom undergoing cyclic motion was used to characterize the system's resolution. The phantom was scanned using a volumetric micro-CT scanner equipped with a flat-panel detector mounted on a slip-ring gantry. Projection images of the moving phantom were collected over a period of 60 s using a variety of acquisition protocols with the rotation period of the gantry ranging from 1 to 5 s. The modulation transfer function (MTF) of the reconstructed images was measured for many combinations of acquisition and reconstruction parameters. The use of the least-error technique was also demonstrated in vivo. RESULTS The motion blurring introduced into the images at physiologically significant velocities of 6 cm∕s agreed well with predicted values; limiting resolution (frequency at 10% MTF) degraded from 2.5 to 1.0 mm(-1) for a velocity of 6 cm∕s and 5 s∕rotation gantry speed. Faster gantry rotation speeds led to improved temporal resolution but the scanner's data storage and transfer rates and field of view limitations made scanning at gantry speeds faster than 2 s∕rotation impractical. CONCLUSIONS The least-error technique effectively eliminates streaking artifact caused by missing views and allows for optimization of image quality in retrospectively gated micro-CT.
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Beraldo FH, Soares IN, Goncalves DF, Fan J, Thomas AA, Santos TG, Mohammad AH, Roffé M, Calder MD, Nikolova S, Hajj GN, Guimaraes AL, Massensini AR, Welch I, Betts DH, Gros R, Drangova M, Watson AJ, Bartha R, Prado VF, Martins VR, Prado MAM. Stress-inducible phosphoprotein 1 has unique cochaperone activity during development and regulates cellular response to ischemia via the prion protein. FASEB J 2013; 27:3594-607. [PMID: 23729591 DOI: 10.1096/fj.13-232280] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Stress-inducible phosphoprotein 1 (STI1) is part of the chaperone machinery, but it also functions as an extracellular ligand for the prion protein. However, the physiological relevance of these STI1 activities in vivo is unknown. Here, we show that in the absence of embryonic STI1, several Hsp90 client proteins are decreased by 50%, although Hsp90 levels are unaffected. Mutant STI1 mice showed increased caspase-3 activation and 50% impairment in cellular proliferation. Moreover, placental disruption and lack of cellular viability were linked to embryonic death by E10.5 in STI1-mutant mice. Rescue of embryonic lethality in these mutants, by transgenic expression of the STI1 gene, supported a unique role for STI1 during embryonic development. The response of STI1 haploinsufficient mice to cellular stress seemed compromised, and mutant mice showed increased vulnerability to ischemic insult. At the cellular level, ischemia increased the secretion of STI1 from wild-type astrocytes by 3-fold, whereas STI1 haploinsufficient mice secreted half as much STI1. Interesting, extracellular STI1 prevented ischemia-mediated neuronal death in a prion protein-dependent way. Our study reveals essential roles for intracellular and extracellular STI1 in cellular resilience.
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Affiliation(s)
- Flavio H Beraldo
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
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Warraich S, Bone DBJ, Quinonez D, Ii H, Choi DS, Holdsworth DW, Drangova M, Dixon SJ, Séguin CA, Hammond JR. Loss of equilibrative nucleoside transporter 1 in mice leads to progressive ectopic mineralization of spinal tissues resembling diffuse idiopathic skeletal hyperostosis in humans. J Bone Miner Res 2013. [PMID: 23184610 DOI: 10.1002/jbmr.1826] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy, characterized by ectopic calcification of spinal tissues. Symptoms include spine pain and stiffness, and in severe cases dysphagia and spinal cord compression. The etiology of DISH is unknown and there are no specific treatments. Recent studies have suggested a role for purine metabolism in the regulation of biomineralization. Equilibrative nucleoside transporter 1 (ENT1) transfers hydrophilic nucleosides, such as adenosine, across the plasma membrane. In mice lacking ENT1, we observed the development of calcified lesions resembling DISH. By 12 months of age, ENT1(-/-) mice exhibited signs of spine stiffness, hind limb dysfunction, and paralysis. Micro-computed tomography (µCT) revealed ectopic mineralization of paraspinal tissues in the cervical-thoracic region at 2 months of age, which extended to the lumbar and caudal regions with advancing age. Energy-dispersive X-ray microanalysis of lesions revealed a high content of calcium and phosphorus with a ratio similar to that of cortical bone. At 12 months of age, histological examination of ENT1(-/-) mice revealed large, irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels, indicating specificity for the axial skeleton. Plasma adenosine levels were significantly greater in ENT1(-/-) mice than in wild-type, consistent with loss of ENT1--a primary adenosine uptake pathway. There was a significant reduction in the expression of Enpp1, Ank, and Alpl in intervertebral discs from ENT1(-/-) mice compared to wild-type mice. Elevated plasma levels of inorganic pyrophosphate in ENT1(-/-) mice indicated generalized disruption of pyrophosphate homeostasis. This is the first report of a role for ENT1 in regulating the calcification of soft tissues. Moreover, ENT1(-/-) mice may be a useful model for investigating pathogenesis and evaluating therapeutics for the prevention of mineralization in DISH and related disorders.
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Affiliation(s)
- Sumeeta Warraich
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
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Detombe SA, Dunmore-Buyze J, Petrov IE, Drangova M. X-ray dose delivered during a longitudinal micro-CT study has no adverse effect on cardiac and pulmonary tissue in C57BL/6 mice. Acta Radiol 2013; 54:435-41. [PMID: 23436828 DOI: 10.1177/0284185113475608] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Micro-computed tomography (micro-CT) offers numerous advantages for small animal imaging, including the ability to monitor the same animals throughout a longitudinal study. However, concerns are often raised regarding the effects of X-ray dose accumulated over the course of the experiment. PURPOSE To scan C57BL/6 mice multiple times per week for 6 weeks, in order to determine the effect of the cumulative dose on pulmonary and cardiac tissue at the end of the study. MATERIAL AND METHODS C57BL/6 male mice were split into two groups (irradiated group = 10, control group = 10). The irradiated group was scanned (80 kVp/50 mA) three times weekly for 6 weeks, resulting in a weekly dose of 0.84 Gy, and a total study dose of 5.04 Gy. The control group was scanned on the final week. Scans from week 6 were reconstructed and the lungs and heart were analyzed. RESULTS Overall, there was no significant difference in lung volume or lung density or in left ventricular volume or ejection fraction between the control group and the irradiated group. Histological samples taken from excised lung and myocardial tissue also showed no evidence of inflammation or fibrosis in the irradiated group. CONCLUSION This study demonstrated that a 5 Gy X-ray dose accumulated over 6 weeks during a longitudinal micro-CT study had no significant effects on the pulmonary and myocardial tissue of C57BL/6 mice. As a result, the many advantages of micro-CT imaging, including rapid acquisition of high-resolution, isotropic images in free-breathing mice, can be taken advantage of in longitudinal studies without concern for negative dose-related effects.
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Affiliation(s)
- Sarah A Detombe
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON
- Department of Medical Biophysics, Western University, London, ON, Canada
| | - Joy Dunmore-Buyze
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON
| | - Ivailo E Petrov
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON
- Department of Medical Biophysics, Western University, London, ON, Canada
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