1
|
Ghauri MD, Šušnjar S, Guadagno CN, Bhattacharya S, Thomasson B, Swartling J, Gautam R, Andersson-Engels S, Konugolu Venkata Sekar S. Hybrid heterogeneous phantoms for biomedical applications: a demonstration to dosimetry validation. BIOMEDICAL OPTICS EXPRESS 2024; 15:863-874. [PMID: 38404353 PMCID: PMC10890852 DOI: 10.1364/boe.514994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 02/27/2024]
Abstract
Phantoms simultaneously mimicking anatomical and optical properties of real tissues can play a pivotal role for improving dosimetry algorithms. The aim of the paper is to design and develop a hybrid phantom model that builds up on the strengths of solid and liquid phantoms for mimicking various anatomical structures for prostate cancer photodynamic therapy (PDT) dosimetry validation. The model comprises of a photosensitizer-embedded gelatin lesion within a liquid Intralipid prostate shape that is surrounded by a solid silicone outer shell. The hybrid phantom was well characterized for optical properties. The final assembled phantom was also evaluated for fluorescence tomographic reconstruction in conjunction with SpectraCure's IDOSE software. The developed model can lead to advancements in dosimetric evaluations. This would improve PDT outlook as a clinical treatment modality and boost phantom based standardization of biophotonic devices globally.
Collapse
Affiliation(s)
- M. Daniyal Ghauri
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- Department of Engineering and Food Sciences, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Stefan Šušnjar
- SpectraCure AB, Gasverksgatan 1, SE-222 29 Lund, Sweden
- Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden
| | - Claudia Nunzia Guadagno
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | - Somdatta Bhattacharya
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | | | | | - Rekha Gautam
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | - Stefan Andersson-Engels
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- Department of Physics, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Sanathana Konugolu Venkata Sekar
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| |
Collapse
|
2
|
Albor-Ramírez E, Reyes-Alberto M, Vidal-Flores LM, Gutierrez-Herrera E, Padilla-Castañeda MA. Agarose Gel Characterization for the Fabrication of Brain Tissue Phantoms for Infrared Multispectral Vision Systems. Gels 2023; 9:944. [PMID: 38131930 PMCID: PMC10742522 DOI: 10.3390/gels9120944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Synthetic phantoms that recreate the characteristics of biological tissues are valuable tools for systematically studying and comprehending physiologies, pathologies, and biological processes related to tissues. The reproduction of mechanical and optical properties allows for the development and evaluation of novel systems and applications in areas such as imaging, optics, ultrasound, or dosimetry, among others. This paper proposes a methodology for manufacturing agarose-based phantoms that mimics the optical properties of healthy brain tissue within the wavelength infrared range of 800 to 820 nm. The fabrication of such phantoms enables the possibility of testing and experimentation in controlled and safe environments toward the design of new near-infrared multispectral imaging systems in neurosurgery. The results of an experimental optical characterization study indicate the validity and reliability of the proposed method for fabricating brain tissue phantoms in a cost-effective and straightforward fashion.
Collapse
Affiliation(s)
| | - Miguel Reyes-Alberto
- Applied Sciences and Technology Institute ICAT, National Autonomous University of Mexico UNAM, Ciudad Universitaria, Mexico City 04510, Mexico; (E.A.-R.); (L.M.V.-F.); (E.G.-H.)
| | | | | | - Miguel A. Padilla-Castañeda
- Applied Sciences and Technology Institute ICAT, National Autonomous University of Mexico UNAM, Ciudad Universitaria, Mexico City 04510, Mexico; (E.A.-R.); (L.M.V.-F.); (E.G.-H.)
| |
Collapse
|
3
|
Kraft M, Ryger S, Berman BP, Downs ME, Jordanova KV, Poorman ME, Oberdick SD, Ogier SE, Russek SE, Dagher J, Keenan KE. Towards a barrier-free anthropomorphic brain phantom for quantitative magnetic resonance imaging: Design, first construction attempt, and challenges. PLoS One 2023; 18:e0285432. [PMID: 37437022 DOI: 10.1371/journal.pone.0285432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/21/2023] [Indexed: 07/14/2023] Open
Abstract
Existing magnetic resonance imaging (MRI) reference objects, or phantoms, are typically constructed from simple liquid or gel solutions in containers with specific geometric configurations to enable multi-year stability. However, there is a need for phantoms that better mimic the human anatomy without barriers between the tissues. Barriers result in regions without MRI signal between the different tissue mimics, which is an artificial image artifact. We created an anatomically representative 3D structure of the brain that mimicked the T1 and T2 relaxation properties of white and gray matter at 3 T. While the goal was to avoid barriers between tissues, the 3D printed barrier between white and gray matter and other flaws in the construction were visible at 3 T. Stability measurements were made using a portable MRI system operating at 64 mT, and T2 relaxation time was stable from 0 to 22 weeks. The phantom T1 relaxation properties did change from 0 to 10 weeks; however, they did not substantially change between 10 weeks and 22 weeks. The anthropomorphic phantom used a dissolvable mold construction method to better mimic anatomy, which worked in small test objects. The construction process, though, had many challenges. We share this work with the hope that the community can build on our experience.
Collapse
Affiliation(s)
- Mikail Kraft
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Slavka Ryger
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Ben P Berman
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Matthew E Downs
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Kalina V Jordanova
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Megan E Poorman
- Hyperfine, Inc, Guilford, Connecticut, United States of America
| | - Samuel D Oberdick
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
- Department of Physics, University of Colorado, Boulder, Colorado, United States of America
| | - Stephen E Ogier
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
- Department of Physics, University of Colorado, Boulder, Colorado, United States of America
| | - Stephen E Russek
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Joseph Dagher
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Kathryn E Keenan
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| |
Collapse
|
4
|
Crasto N, Kirubarajan A, Sussman D. Anthropomorphic brain phantoms for use in MRI systems: a systematic review. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 35:277-289. [PMID: 34463866 DOI: 10.1007/s10334-021-00953-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To provide a systematic review of available brain MRI phantoms for comparison of structural and functional characteristics. MATERIALS AND METHODS Phantoms were identified from a literature search using two databases including Google Scholar and PubMed. Narrow inclusion criteria were followed for identification of only tissue-mimicking MRI phantoms excluding digital, computational, or numerical phantoms. Assessment criteria for the identified phantoms was based on three categories being anatomical accuracy, tissue-mimicking materials, and exhibiting relaxation times approximating in-vivo tissues. The available features and uses of each phantom were reported and discussed using the assessment criteria. RESULTS Ten phantoms were identified after screening; each proposed phantom was then summarized in a table (Table 2). Significant features and characteristics were shown in the comparisons of phantom type in each category, being anthropomorphic vs. traditional phantoms. Anthropomorphic phantoms had more anatomically accurate features than traditional phantoms. On the other hand, traditional phantoms commonly used effective tissue-mimicking materials and accurate electromagnetic properties. DISCUSSION The findings provide an overview of the different proposed tissue-mimicking MRI brain phantoms available. Various uses and features are highlighted by comparing criteria such as anatomical accuracy, tissue-mimicking material, and electromagnetic properties. Tissue-mimicking MRI phantoms are an extremely useful tool for researchers and clinicians. Future applications include personalized phantom technology and validation of MR imaging and segmentation methods.
Collapse
Affiliation(s)
- Noelle Crasto
- Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, ON, M5B 2K3, Canada
- Institute for Biomedical Engineering, Science and Technology (iBEST) at Ryerson University and St. Michael's Hospital, Toronto, ON, M5B 1T8, Canada
| | - Abirami Kirubarajan
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Dafna Sussman
- Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, ON, M5B 2K3, Canada.
- Institute for Biomedical Engineering, Science and Technology (iBEST) at Ryerson University and St. Michael's Hospital, Toronto, ON, M5B 1T8, Canada.
- The Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, M5B 1T8, Canada.
- Department of Biomedical Physics, Ryerson University, Toronto, ON, M5B 2K3, Canada.
- Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Toronto, Toronto, M5S 1A8, Canada.
| |
Collapse
|
5
|
Gorelik N, Patil K, Chen SJS, Bhatnagar S, Faingold R. Impact of Simulation Training on Radiology Resident Performance in Neonatal Head Ultrasound. Acad Radiol 2021; 28:859-867. [PMID: 32768353 DOI: 10.1016/j.acra.2020.06.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 11/16/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to determine whether resident performance in head ultrasound on neonates improves following brain phantom simulation training. MATERIALS AND METHODS Ten junior radiology residents with at least one year of radiology training were divided into two equal groups. Both groups received a detailed head ultrasound protocol sheet and observed a technologist perform a head ultrasound on a neonatal patient at the beginning of their first pediatric radiology rotation. Both groups of residents also received teaching with a brain phantom model. Group A residents independently performed one head ultrasound exam, subsequently received phantom simulation training, and then performed a post-training head ultrasound exam. Group B residents received phantom simulation training prior to their first head ultrasound exam. Three pediatric radiologists independently and blindly reviewed the ultrasound images of each head ultrasound exam for proficiency of image acquisition using a validated scoring system. Scores of Group A residents prior to phantom training were compared to their scores after phantom training as well as to scores of Group B residents using simple linear regression. RESULTS There was a statistically significant improvement in the performance of head ultrasound on neonates when comparing the same residents pre- and postphantom training (p = 0.003). Residents who initially trained with the phantom performed significantly better on their first head ultrasound examination on a neonate than those residents who did not (p = 0.005). CONCLUSION Our novel head ultrasound phantom training model significantly improves radiology resident performance of head ultrasound on neonates and may, therefore, be beneficial for residency education.
Collapse
Affiliation(s)
- Natalia Gorelik
- Department of Diagnostic Radiology, McGill University Health Center, 1001 Decarie Blvd, Montreal, QC, Canada H4A 3J1.
| | - Kedar Patil
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Sean Jy-Shyang Chen
- McConnell Brain Imaging, Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Sahir Bhatnagar
- Departments of Epidemiology, Biostatistics and Occupational Health, Diagnostic Radiology, McGill University, Montreal, QC, Canada
| | - Ricardo Faingold
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
6
|
Winkler-Schwartz A, Yilmaz R, Tran DH, Gueziri HE, Ying B, Tuznik M, Fonov V, Collins L, Rudko DA, Li J, Debergue P, Pazos V, Del Maestro R. Creating a Comprehensive Research Platform for Surgical Technique and Operative Outcome in Primary Brain Tumor Neurosurgery. World Neurosurg 2020; 144:e62-e71. [DOI: 10.1016/j.wneu.2020.07.209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 02/05/2023]
|
7
|
Hagiwara A, Fujita S, Ohno Y, Aoki S. Variability and Standardization of Quantitative Imaging: Monoparametric to Multiparametric Quantification, Radiomics, and Artificial Intelligence. Invest Radiol 2020; 55:601-616. [PMID: 32209816 PMCID: PMC7413678 DOI: 10.1097/rli.0000000000000666] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
Radiological images have been assessed qualitatively in most clinical settings by the expert eyes of radiologists and other clinicians. On the other hand, quantification of radiological images has the potential to detect early disease that may be difficult to detect with human eyes, complement or replace biopsy, and provide clear differentiation of disease stage. Further, objective assessment by quantification is a prerequisite of personalized/precision medicine. This review article aims to summarize and discuss how the variability of quantitative values derived from radiological images are induced by a number of factors and how these variabilities are mitigated and standardization of the quantitative values are achieved. We discuss the variabilities of specific biomarkers derived from magnetic resonance imaging and computed tomography, and focus on diffusion-weighted imaging, relaxometry, lung density evaluation, and computer-aided computed tomography volumetry. We also review the sources of variability and current efforts of standardization of the rapidly evolving techniques, which include radiomics and artificial intelligence.
Collapse
Affiliation(s)
- Akifumi Hagiwara
- From the Department of Radiology, Juntendo University School of Medicine, Tokyo
| | | | - Yoshiharu Ohno
- Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Shigeki Aoki
- From the Department of Radiology, Juntendo University School of Medicine, Tokyo
| |
Collapse
|
8
|
Mackle EC, Shapey J, Maneas E, Saeed SR, Bradford R, Ourselin S, Vercauteren T, Desjardins AE. Patient-Specific Polyvinyl Alcohol Phantom Fabrication with Ultrasound and X-Ray Contrast for Brain Tumor Surgery Planning. J Vis Exp 2020. [PMID: 32744524 PMCID: PMC7610642 DOI: 10.3791/61344] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phantoms are essential tools for clinical training, surgical planning and the development of novel medical devices. However, it is challenging to create anatomically accurate head phantoms with realistic brain imaging properties because standard fabrication methods are not optimized to replicate any patient-specific anatomical detail and 3D printing materials are not optimized for imaging properties. In order to test and validate a novel navigation system for use during brain tumor surgery, an anatomically accurate phantom with realistic imaging and mechanical properties was required. Therefore, a phantom was developed using real patient data as input and 3D printing of molds to fabricate a patient-specific head phantom comprising the skull, brain and tumor with both ultrasound and X-ray contrast. The phantom also had mechanical properties that allowed the phantom tissue to be manipulated in a similar manner to how human brain tissue is handled during surgery. The phantom was successfully tested during a surgical simulation in a virtual operating room. The phantom fabrication method uses commercially available materials and is easy to reproduce. The 3D printing files can be readily shared, and the technique can be adapted to encompass many different types of tumor.
Collapse
Affiliation(s)
- Eleanor C Mackle
- Wellcome / EPSRC Centre for Interventional and Surgical Sciences, University College London; Department of Medical Physics and Biomedical Engineering, University College London;
| | - Jonathan Shapey
- Wellcome / EPSRC Centre for Interventional and Surgical Sciences, University College London; Department of Medical Physics and Biomedical Engineering, University College London; Department of Neurosurgery, National Hospital for Neurology and Neurosurgery; School of Biomedical Engineering & Imaging Sciences, King's College London
| | - Efthymios Maneas
- Wellcome / EPSRC Centre for Interventional and Surgical Sciences, University College London; Department of Medical Physics and Biomedical Engineering, University College London
| | - Shakeel R Saeed
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery; The Ear Institute, University College London; The Royal National Throat, Nose and Ear Hospital, London
| | - Robert Bradford
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery
| | - Sebastien Ourselin
- School of Biomedical Engineering & Imaging Sciences, King's College London
| | - Tom Vercauteren
- School of Biomedical Engineering & Imaging Sciences, King's College London
| | - Adrien E Desjardins
- Wellcome / EPSRC Centre for Interventional and Surgical Sciences, University College London; Department of Medical Physics and Biomedical Engineering, University College London
| |
Collapse
|
9
|
Elvira L, Durán C, Higuti RT, Tiago MM, Ibáñez A, Parrilla M, Valverde E, Jiménez J, Bassat Q. Development and Characterization of Medical Phantoms for Ultrasound Imaging Based on Customizable and Mouldable Polyvinyl Alcohol Cryogel-Based Materials and 3-D Printing: Application to High-Frequency Cranial Ultrasonography in Infants. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2226-2241. [PMID: 31128769 DOI: 10.1016/j.ultrasmedbio.2019.04.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcohol-based cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.
Collapse
Affiliation(s)
- Luis Elvira
- Instituto de Tecnologías Físicas y de la Información, CSIC, Madrid, Spain.
| | - Carmen Durán
- Instituto de Tecnologías Físicas y de la Información, CSIC, Madrid, Spain
| | - Ricardo T Higuti
- Univ Estadual Paulista, Campus of Ilha Solteira, Departament of Electrical Engineering, São Paulo, Brazil
| | - Marcelo M Tiago
- Federal University of Ouro Preto (UFOP), Department of Electrical Engineering, João Monlevade, Minas Gerais, Brazil
| | - Alberto Ibáñez
- Instituto de Tecnologías Físicas y de la Información, CSIC, Madrid, Spain
| | | | - Eva Valverde
- Unidad de Neonatología, Hospital La Paz, Madrid, Spain
| | - Javier Jiménez
- New Born Solutions, Barcelona Scientific Park, Barcelona, Spain
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique; ICREA, Pg. Lluís Companys 23, Barcelona, Spain; Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain
| |
Collapse
|
10
|
Breimer GE, Haji FA, Bodani V, Cunningham MS, Lopez-Rios AL, Okrainec A, Drake JM. Simulation-based Education for Endoscopic Third Ventriculostomy: A Comparison Between Virtual and Physical Training Models. Oper Neurosurg (Hagerstown) 2019; 13:89-95. [PMID: 28931258 DOI: 10.1227/neu.0000000000001317] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 03/03/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The relative educational benefits of virtual reality (VR) and physical simulation models for endoscopic third ventriculostomy (ETV) have not been evaluated "head to head." OBJECTIVE To compare and identify the relative utility of a physical and VR ETV simulation model for use in neurosurgical training. METHODS Twenty-three neurosurgical residents and 3 fellows performed an ETV on both a physical and VR simulation model. Trainees rated the models using 5-point Likert scales evaluating the domains of anatomy, instrument handling, procedural content, and the overall fidelity of the simulation. Paired t tests were performed for each domain's mean overall score and individual items. RESULTS The VR model has relative benefits compared with the physical model with respect to realistic representation of intraventricular anatomy at the foramen of Monro (4.5, standard deviation [SD] = 0.7 vs 4.1, SD = 0.6; P = .04) and the third ventricle floor (4.4, SD = 0.6 vs 4.0, SD = 0.9; P = .03), although the overall anatomy score was similar (4.2, SD = 0.6 vs 4.0, SD = 0.6; P = .11). For overall instrument handling and procedural content, the physical simulator outperformed the VR model (3.7, SD = 0.8 vs 4.5; SD = 0.5, P < .001 and 3.9; SD = 0.8 vs 4.2, SD = 0.6; P = .02, respectively). Overall task fidelity across the 2 simulators was not perceived as significantly different. CONCLUSION Simulation model selection should be based on educational objectives. Training focused on learning anatomy or decision-making for anatomic cues may be aided with the VR simulation model. A focus on developing manual dexterity and technical skills using endoscopic equipment in the operating room may be better learned on the physical simulation model.
Collapse
Affiliation(s)
- Gerben E Breimer
- Centre for Image Guided Innovation and Therapeutic Intervention (CIGITI), The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neuro-surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neurosurgery, University Medical Center Groningen, Groningen, the Netherlands
| | - Faizal A Haji
- Division of Clinical Neurological Sci-ences, Western University, London, Ontario, Canada.,SickKids Learning Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Wilson Centre for Research in Education, University of Toronto, Toronto, Ontario, Canada
| | - Vivek Bodani
- Centre for Image Guided Innovation and Therapeutic Intervention (CIGITI), The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neuro-surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa S Cunningham
- Temerty/Chang International Centre for Telesimulation and Innovation Medical Education, Toronto Western Hospital-University Health Network, Toronto, Ontario, Canada
| | - Adriana-Lucia Lopez-Rios
- Temerty/Chang International Centre for Telesimulation and Innovation Medical Education, Toronto Western Hospital-University Health Network, Toronto, Ontario, Canada
| | - Allan Okrainec
- Temerty/Chang International Centre for Telesimulation and Innovation Medical Education, Toronto Western Hospital-University Health Network, Toronto, Ontario, Canada.,Division of General Surgery, Toronto Western Hospital-University Health Network, Toronto, Ontario, Canada
| | - James M Drake
- Centre for Image Guided Innovation and Therapeutic Intervention (CIGITI), The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neuro-surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| |
Collapse
|
11
|
Amiri H, Brouwer I, Kuijer JPA, de Munck JC, Barkhof F, Vrenken H. Novel imaging phantom for accurate and robust measurement of brain atrophy rates using clinical MRI. NEUROIMAGE-CLINICAL 2019; 21:101667. [PMID: 30665101 PMCID: PMC6350260 DOI: 10.1016/j.nicl.2019.101667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 11/26/2018] [Accepted: 01/04/2019] [Indexed: 01/17/2023]
Abstract
Brain volume loss, or atrophy, has been proven to be an important characteristic of neurological diseases such as Alzheimer's disease and multiple sclerosis. To use atrophy rate as a reliable clinical biomarker and to increase statistical power in clinical treatment trials, measurement variability needs to be minimized. Among other sources, systematic differences between different MR scanners are suspected to contribute to this variability. In this study we developed and performed initial validation tests of an MR-compatible phantom and analysis software for robust and reliable evaluation of the brain volume loss. The phantom contained three inflatable models of brain structures, i.e. cerebral hemisphere, putamen, and caudate nucleus. Software to reliably quantify volumes form the phantom images was also developed. To validate the method, the phantom was imaged using 3D T1-weighted protocols at three clinical 3T MR scanners from different vendors. Calculated volume change from MRI was compared with the known applied volume change using ICC and mean absolute difference. As assessed by the ICC, the agreement between our developed software and the applied volume change for different structures ranged from 0.999-1 for hemisphere, 0.976-0.998 for putamen, and 0.985-0.999 for caudate nucleus. The mean absolute differences between measured and applied volume change were 109-332 μL for hemisphere, 2.9-11.9 μL for putamen, and 2.2-10.1 μL for caudate nucleus. This method offers a reliable and robust measurement of volume change using MR images and could potentially be used to standardize clinical measurement of atrophy rates.
Collapse
Affiliation(s)
- Houshang Amiri
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands..
| | - Iman Brouwer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Joost P A Kuijer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Jan C de Munck
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Frederik Barkhof
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands.; Institutes of Neurology and Healthcare Engineering, UCL, London, UK
| | - Hugo Vrenken
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| |
Collapse
|
12
|
Altermatt A, Santini F, Deligianni X, Magon S, Sprenger T, Kappos L, Cattin P, Wuerfel J, Gaetano L. Design and construction of an innovative brain phantom prototype for MRI. Magn Reson Med 2018; 81:1165-1171. [PMID: 30221790 DOI: 10.1002/mrm.27464] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 11/06/2022]
Abstract
PURPOSE The purpose of this project was to construct a physical brain phantom for MRI, mimicking structure and T1 relaxation properties of white matter (WM) and gray matter (GM). METHODS The phantom design comprised 2 compartments, 1 resembling the WM and 1 resembling the GM. Their T1 relaxation times, as assessed using an inversion recovery turbo spin echo sequence, were reproduced using an agar gel doped with contrast agent (CA) and their folding patterns were simulated through a molding-casting procedure using 3D-printed casts and flexible silicone molds. Three versions of the assembling procedure were adopted to build: Phantom1 without any separation; Phantom2 with a varnish layer; and Phantom3 with a thin wax layer between the compartments. RESULTS Phantom1 was characterized by an immediate diffusion of CA between the 2 compartments. Phantom2 and Phantom3, instead, showed relaxation times and shape comparable with the target ones identified in a healthy control subject (WM: 754 ± 40 ms; GM: 1277 ± 96 ms). Moreover, both compartments revealed intact gyri and sulci. However, the diffusion of CA made Phantom2 stable only for a short period of time. Phantom3 showed stability within a time window of several days but the wax layer between the WM and GM was visible in the MRI. CONCLUSION Structural and intensity properties of the constructed phantoms are useful in evaluating and validating steps from image acquisition to image processing. Moreover, the described constructing procedure and its modular design make it adjustable to a variety of applications.
Collapse
Affiliation(s)
- Anna Altermatt
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Francesco Santini
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland.,Division of Radiological Physics, Department of Radiology, University Hospital of Basel, Basel, Switzerland
| | - Xeni Deligianni
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland.,Division of Radiological Physics, Department of Radiology, University Hospital of Basel, Basel, Switzerland
| | - Stefano Magon
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland.,Neurologic Clinic and Policlinic, Department of Neurology, University Hospital of Basel, Basel, Switzerland
| | - Till Sprenger
- Neurologic Clinic and Policlinic, Department of Neurology, University Hospital of Basel, Basel, Switzerland.,Department of Neurology, DKD HELIOS Klinik, Wiesbaden, Germany
| | - Ludwig Kappos
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland.,Neurologic Clinic and Policlinic, Department of Neurology, University Hospital of Basel, Basel, Switzerland
| | | | - Jens Wuerfel
- Medical Image Analysis Center (MIAC) AG, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Laura Gaetano
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland.,Neurologic Clinic and Policlinic, Department of Neurology, University Hospital of Basel, Basel, Switzerland
| |
Collapse
|
13
|
Regional variations in stiffness in live mouse brain tissue determined by depth-controlled indentation mapping. Sci Rep 2018; 8:12517. [PMID: 30131608 PMCID: PMC6104037 DOI: 10.1038/s41598-018-31035-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 08/10/2018] [Indexed: 11/08/2022] Open
Abstract
The mechanical properties of brain tissue play a pivotal role in neurodevelopment and neurological disorders. Yet, at present, there is no consensus on how the different structural parts of the tissue contribute to its stiffness variations. Here, we have gathered depth-controlled indentation viscoelasticity maps of the hippocampus of acute horizontal live mouse brain slices. Our results confirm the highly viscoelestic nature of brain tissue. We further show that the mechanical properties are non-uniform and at least related to differences in morphological composition. Interestingly, areas with higher nuclear density appear to be softer than areas with lower nuclear density.
Collapse
|
14
|
Filippou V, Tsoumpas C. Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound. Med Phys 2018; 45. [PMID: 29933508 PMCID: PMC6849595 DOI: 10.1002/mp.13058] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/03/2018] [Accepted: 06/15/2018] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Printing technology, capable of producing three-dimensional (3D) objects, has evolved in recent years and provides potential for developing reproducible and sophisticated physical phantoms. 3D printing technology can help rapidly develop relatively low cost phantoms with appropriate complexities, which are useful in imaging or dosimetry measurements. The need for more realistic phantoms is emerging since imaging systems are now capable of acquiring multimodal and multiparametric data. This review addresses three main questions about the 3D printers currently in use, and their produced materials. The first question investigates whether the resolution of 3D printers is sufficient for existing imaging technologies. The second question explores if the materials of 3D-printed phantoms can produce realistic images representing various tissues and organs as taken by different imaging modalities such as computer tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), ultrasound (US), and mammography. The emergence of multimodal imaging increases the need for phantoms that can be scanned using different imaging modalities. The third question probes the feasibility and easiness of "printing" radioactive or nonradioactive solutions during the printing process. METHODS A systematic review of medical imaging studies published after January 2013 is performed using strict inclusion criteria. The databases used were Scopus and Web of Knowledge with specific search terms. In total, 139 papers were identified; however, only 50 were classified as relevant for this paper. In this review, following an appropriate introduction and literature research strategy, all 50 articles are presented in detail. A summary of tables and example figures of the most recent advances in 3D printing for the purposes of phantoms across different imaging modalities are provided. RESULTS All 50 studies printed and scanned phantoms in either CT, PET, SPECT, mammography, MRI, and US-or a combination of those modalities. According to the literature, different parameters were evaluated depending on the imaging modality used. Almost all papers evaluated more than two parameters, with the most common being Hounsfield units, density, attenuation and speed of sound. CONCLUSIONS The development of this field is rapidly evolving and becoming more refined. There is potential to reach the ultimate goal of using 3D phantoms to get feedback on imaging scanners and reconstruction algorithms more regularly. Although the development of imaging phantoms is evident, there are still some limitations to address: One of which is printing accuracy, due to the printer properties. Another limitation is the materials available to print: There are not enough materials to mimic all the tissue properties. For example, one material can mimic one property-such as the density of real tissue-but not any other property, like speed of sound or attenuation.
Collapse
Affiliation(s)
- Valeria Filippou
- Institute of Medical and Biological EngineeringFaculty of Mechanical EngineeringUniversity of LeedsLeedsLS2 9JTWest YorkshireUK
| | - Charalampos Tsoumpas
- Department of Biomedical Imaging ScienceSchool of MedicineUniversity of LeedsLeedsLS2 9NLWest YorkshireUK
| |
Collapse
|
15
|
Qiu K, Haghiashtiani G, McAlpine MC. 3D Printed Organ Models for Surgical Applications. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:287-306. [PMID: 29589961 PMCID: PMC6082023 DOI: 10.1146/annurev-anchem-061417-125935] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Medical errors are a major concern in clinical practice, suggesting the need for advanced surgical aids for preoperative planning and rehearsal. Conventionally, CT and MRI scans, as well as 3D visualization techniques, have been utilized as the primary tools for surgical planning. While effective, it would be useful if additional aids could be developed and utilized in particularly complex procedures involving unusual anatomical abnormalities that could benefit from tangible objects providing spatial sense, anatomical accuracy, and tactile feedback. Recent advancements in 3D printing technologies have facilitated the creation of patient-specific organ models with the purpose of providing an effective solution for preoperative planning, rehearsal, and spatiotemporal mapping. Here, we review the state-of-the-art in 3D printed, patient-specific organ models with an emphasis on 3D printing material systems, integrated functionalities, and their corresponding surgical applications and implications. Prior limitations, current progress, and future perspectives in this important area are also broadly discussed.
Collapse
Affiliation(s)
- Kaiyan Qiu
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA;
| | - Ghazaleh Haghiashtiani
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA;
| | - Michael C McAlpine
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA;
| |
Collapse
|
16
|
Cox BL, Ludwig KD, Adamson EB, Eliceiri KW, Fain SB. An open source, 3D printed preclinical MRI phantom for repeated measures of contrast agents and reference standards. Biomed Phys Eng Express 2018; 4. [PMID: 29399370 PMCID: PMC5790173 DOI: 10.1088/2057-1976/aa9491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In medical imaging, clinicians, researchers and technicians have begun to use 3D printing to create specialized phantoms to replace commercial ones due to their customizable and iterative nature. Presented here is the design of a 3D printed open source, reusable magnetic resonance imaging (MRI) phantom, capable of flood-filling, with removable samples for measurements of contrast agent solutions and reference standards, and for use in evaluating acquisition techniques and image reconstruction performance. The phantom was designed using SolidWorks, a computer-aided design software package. The phantom consists of custom and off-the-shelf parts and incorporates an air hole and Luer Lock system to aid in flood filling, a marker for orientation of samples in the filled mode and bolt and tube holes for assembly. The cost of construction for all materials is under $90. All design files are open-source and available for download. To demonstrate utility, B0 field mapping was performed using a series of gadolinium concentrations in both the unfilled and flood-filled mode. An excellent linear agreement (R2>0.998) was observed between measured relaxation rates (R1/R2) and gadolinium concentration. The phantom provides a reliable setup to test data acquisition and reconstruction methods and verify physical alignment in alternative nuclei MRI techniques (e.g. carbon-13 and fluorine-19 MRI). A cost-effective, open-source MRI phantom design for repeated quantitative measurement of contrast agents and reference standards in preclinical research is presented. Specifically, the work is an example of how the emerging technology of 3D printing improves flexibility and access for custom phantom design.
Collapse
Affiliation(s)
- B L Cox
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI 53705.,Morgridge Institute for Research, 330 N. Orchard St., Madison, WI 53715.,Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, 1675 Observatory Dr., Madison, WI 53706
| | - K D Ludwig
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI 53705
| | - E B Adamson
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI 53705
| | - K W Eliceiri
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI 53705.,Morgridge Institute for Research, 330 N. Orchard St., Madison, WI 53715.,Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, 1675 Observatory Dr., Madison, WI 53706.,Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Dr., Madison, WI 53706
| | - S B Fain
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI 53705.,Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Dr., Madison, WI 53706.,Department of Radiology, University of Wisconsin-Madison, E3/366 Clinical Science Center, 600 Highland Ave., Madison, WI 53792
| |
Collapse
|
17
|
Matrone G, Ramalli A, Savoia AS, Quaglia F, Castellazzi G, Morbini P, Piastra M. An Experimental Protocol for Assessing the Performance of New Ultrasound Probes Based on CMUT Technology in Application to Brain Imaging. J Vis Exp 2017. [PMID: 28994803 DOI: 10.3791/55798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The possibility to perform an early and repeatable assessment of imaging performance is fundamental in the design and development process of new ultrasound (US) probes. Particularly, a more realistic analysis with application-specific imaging targets can be extremely valuable to assess the expected performance of US probes in their potential clinical field of application. The experimental protocol presented in this work was purposely designed to provide an application-specific assessment procedure for newly-developed US probe prototypes based on Capacitive Micromachined Ultrasonic Transducer (CMUT) technology in relation to brain imaging. The protocol combines the use of a bovine brain fixed in formalin as the imaging target, which ensures both realism and repeatability of the described procedures, and of neuronavigation techniques borrowed from neurosurgery. The US probe is in fact connected to a motion tracking system which acquires position data and enables the superposition of US images to reference Magnetic Resonance (MR) images of the brain. This provides a means for human experts to perform a visual qualitative assessment of the US probe imaging performance and to compare acquisitions made with different probes. Moreover, the protocol relies on the use of a complete and open research and development system for US image acquisition, i.e. the Ultrasound Advanced Open Platform (ULA-OP) scanner. The manuscript describes in detail the instruments and procedures involved in the protocol, in particular for the calibration, image acquisition and registration of US and MR images. The obtained results prove the effectiveness of the overall protocol presented, which is entirely open (within the limits of the instrumentation involved), repeatable, and covers the entire set of acquisition and processing activities for US images.
Collapse
Affiliation(s)
- Giulia Matrone
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia
| | | | | | | | - Gloria Castellazzi
- Brain Connectivity Center, BCC, Istituto Neurologico Nazionale Fondazione C. Mondino I.R.C.C.S
| | - Patrizia Morbini
- Department of Molecular Medicine - Unit of Pathology, University of Pavia, Foundation IRCCS Policlinico San Matteo
| | - Marco Piastra
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia;
| |
Collapse
|
18
|
Cutolo F, Meola A, Carbone M, Sinceri S, Cagnazzo F, Denaro E, Esposito N, Ferrari M, Ferrari V. A new head-mounted display-based augmented reality system in neurosurgical oncology: a study on phantom. Comput Assist Surg (Abingdon) 2017; 22:39-53. [PMID: 28754068 DOI: 10.1080/24699322.2017.1358400] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Fabrizio Cutolo
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
- Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Antonio Meola
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Marina Carbone
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
| | - Sara Sinceri
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
| | | | - Ennio Denaro
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
| | - Nicola Esposito
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
| | - Mauro Ferrari
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
- Department of Vascular Surgery, Pisa University Medical School, Pisa, Italy
| | - Vincenzo Ferrari
- Department of Translational Research and New Technologies in Medicine and Surgery, EndoCAS Center, University of Pisa, Pisa, Italy
- Department of Information Engineering, University of Pisa, Pisa, Italy
| |
Collapse
|
19
|
Li W, Belmont B, Greve JM, Manders AB, Downey BC, Zhang X, Xu Z, Guo D, Shih A. Polyvinyl chloride as a multimodal tissue-mimicking material with tuned mechanical and medical imaging properties. Med Phys 2017; 43:5577. [PMID: 27782725 DOI: 10.1118/1.4962649] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The mechanical and imaging properties of polyvinyl chloride (PVC) can be adjusted to meet the needs of researchers as a tissue-mimicking material. For instance, the hardness can be adjusted by changing the ratio of softener to PVC polymer, mineral oil can be added for lubrication in needle insertion, and glass beads can be added to scatter acoustic energy similar to biological tissue. Through this research, the authors sought to develop a regression model to design formulations of PVC with targeted mechanical and multimodal medical imaging properties. METHODS The design of experiment was conducted by varying three factors-(1) the ratio of softener to PVC polymer, (2) the mass fraction of mineral oil, and (3) the mass fraction of glass beads-and measuring the mechanical properties (elastic modulus, hardness, viscoelastic relaxation time constant, and needle insertion friction force) and the medical imaging properties [speed of sound, acoustic attenuation coefficient, magnetic resonance imaging time constants T1 and T2, and the transmittance of the visible light at wavelengths of 695 nm (Tλ695) and 532 nm (Tλ532)] on twelve soft PVC samples. A regression model was built to describe the relationship between the mechanical and medical imaging properties and the values of the three composition factors of PVC. The model was validated by testing the properties of a PVC sample with a formulation distinct from the twelve samples. RESULTS The tested soft PVC had elastic moduli from 6 to 45 kPa, hardnesses from 5 to 50 Shore OOO-S, viscoelastic stress relaxation time constants from 114.1 to 191.9 s, friction forces of 18 gauge needle insertion from 0.005 to 0.086 N/mm, speeds of sound from 1393 to 1407 m/s, acoustic attenuation coefficients from 0.38 to 0.61 (dB/cm)/MHz, T1 relaxation times from 426.3 to 450.2 ms, T2 relaxation times from 21.5 to 28.4 ms, Tλ695 from 46.8% to 92.6%, and Tλ532 from 41.1% to 86.3%. Statistically significant factors of each property were identified. The regression model relating the mechanical and medical imaging properties and their corresponding significant factors had a good fit. The validation tests showed a small discrepancy between the model predicted values and experimental data (all less than 5% except the needle insertion friction force). CONCLUSIONS The regression model developed in this paper can be used to design soft PVC with targeted mechanical and medical imaging properties.
Collapse
Affiliation(s)
- Weisi Li
- School of Mechanical Engineering, Dalian University of Technology, Dalian, Liaoning 110042, China and Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Barry Belmont
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Joan M Greve
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Adam B Manders
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Brian C Downey
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Xi Zhang
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Zhen Xu
- Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| | - Dongming Guo
- School of Mechanical Engineering, Dalian University of Technology, Dalian, Liaoning 110042, China
| | - Albert Shih
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109 and Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109
| |
Collapse
|
20
|
Self-similarity weighted mutual information: A new nonrigid image registration metric. Med Image Anal 2014; 18:343-58. [DOI: 10.1016/j.media.2013.12.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 10/07/2013] [Accepted: 12/07/2013] [Indexed: 11/19/2022]
|
21
|
Minton JA, Iravani A, Azizeh-Mitra Yousefi. Improving the homogeneity of tissue-mimicking cryogel phantoms for medical imaging. Med Phys 2012; 39:6796-807. [DOI: 10.1118/1.4757617] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
22
|
Dieringer MA, Hentschel J, de Quadros T, von Knobelsdorff-Brenkenhoff F, Hoffmann W, Niendorf T, Schulz-Menger J. Design, construction, and evaluation of a dynamic MR compatible cardiac left ventricle model. Med Phys 2012; 39:4800-6. [PMID: 22894405 DOI: 10.1118/1.4736954] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE Development of magnetic resonance (MR) sequences is important to answer clinical questions and to overcome current limitations. To meet the challenges of cardiac MR, dynamic and reproducible testing conditions are required. We aimed at developing a dynamic MR-compatible cardiac left ventricle model that imitates myocardial tissue properties and simulates dynamic motion. METHODS A dynamic left ventricle silicone model was designed to match myocardial T(1) and T(2) relaxation times. Silicone mixtures were explored to replicate T(2) values of myocardial edema. A controllable piston pump was constructed to produce pulsatile flow paradigms. They were validated against flow sensors and MR data, including SSFP-based and phase-contrast-based sequences. A dedicated software interface was developed for the control. RESULTS Model dimensions represented cardiac left ventricle dimensions of healthy men. The range of end diastolic volumes was 85-175 ml, depending on the driven stroke volume. Stroke volume quantification for flow paradigms of 30∕60∕90∕120 ml resulted in 29.2∕57.6∕88.8∕118.4 ml by MR volumetry, 29.6∕59.9∕89.4∕119.0 ml by phase contrast measurements, and 29.9∕60.4∕91.1∕120.9 ml by flow meter revealing consistency. The system accurately replicated physiological and pathophysiological flow paradigms. The silicon model exhibited T(1) of 1002 ± 8 ms, T(2) of 58 ± 1 ms. Signal intensities (a.u.) of the ventricle model were 128 ± 23 for FGRE (vs 138 ± 17 in vivo) and 1156 ± 37 for b-SSFP (vs 991 ± 96 in vivo). T(2) of 75 ± 2 ms was achieved for the myocardial pathology. CONCLUSIONS We developed a controllable left ventricle model resembling MR signal characteristics of human myocardium, including pathological conditions, and allowing for the replication of contraction and flow paradigms.
Collapse
Affiliation(s)
- Matthias A Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin 13125, Germany.
| | | | | | | | | | | | | |
Collapse
|