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Flynn MJ, Mayfield AM, Du R, Gradinaru V, Elowitz MB. Synthetic dosage-compensating miRNA circuits allow precision gene therapy for Rett syndrome. bioRxiv 2024:2024.03.13.584179. [PMID: 38559034 PMCID: PMC10980028 DOI: 10.1101/2024.03.13.584179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
A longstanding challenge in gene therapy is expressing a dosage-sensitive gene within a tight therapeutic window. For example, loss of MECP2 function causes Rett syndrome, while its duplication causes MECP2 duplication syndrome. Viral gene delivery methods generate variable numbers of gene copies in individual cells, creating a need for gene dosage-invariant expression systems. Here, we introduce a compact miRNA-based, incoherent feed-forward loop circuit that achieves precise control of Mecp2 expression in cells and brains, and improves outcomes in an AAV-based mouse model of Rett syndrome gene therapy. Single molecule analysis of endogenous and ectopic Mecp2 mRNA revealed precise, sustained expression across a broad range of gene dosages. Delivered systemically in a brain-targeting AAV capsid, the circuit strongly suppressed Rett behavioral symptoms for over 24 weeks, outperforming an unregulated gene therapy. These results demonstrate that synthetic miRNA-based regulatory circuits can enable precise in vivo expression to improve the safety and efficacy of gene therapy.
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Affiliation(s)
- Michael J. Flynn
- Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Acacia M.H. Mayfield
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Rongrong Du
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Viviana Gradinaru
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Michael B. Elowitz
- Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA 91125
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125
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Du R, Flynn MJ, Honsa M, Jungmann R, Elowitz MB. miRNA circuit modules for precise, tunable control of gene expression. bioRxiv 2024:2024.03.12.583048. [PMID: 38559239 PMCID: PMC10979901 DOI: 10.1101/2024.03.12.583048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The ability to express transgenes at specified levels is critical for understanding cellular behaviors, and for applications in gene and cell therapy. Transfection, viral vectors, and other gene delivery methods produce varying protein expression levels, with limited quantitative control, while targeted knock-in and stable selection are inefficient and slow. Active compensation mechanisms can improve precision, but the need for additional proteins or lack of tunability have prevented their widespread use. Here, we introduce a toolkit of compact, synthetic miRNA-based circuit modules that provide precise, tunable control of transgenes across diverse cell types. These circuits, termed DIMMERs (Dosage-Invariant miRNA-Mediated Expression Regulators) use multivalent miRNA regulatory interactions within an incoherent feed-forward loop architecture to achieve nearly uniform protein expression over more than two orders of magnitude variation in underlying gene dosages or transcription rates. They also allow coarse and fine control of expression, and are portable, functioning across diverse cell types. In addition, a heuristic miRNA design algorithm enables the creation of orthogonal circuit variants that independently control multiple genes in the same cell. These circuits allowed dramatically improved CRISPR imaging, and super-resolution imaging of EGFR receptors with transient transfections. The toolbox provided here should allow precise, tunable, dosage-invariant expression for research, gene therapy, and other biotechnology applications.
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Affiliation(s)
- Rongrong Du
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael J. Flynn
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Monique Honsa
- Max Planck Institute of Biochemistry, Martinsried, Germany; Faculty of Physics, Ludwig Maximilian University, Munich, Germany
| | - Ralf Jungmann
- Max Planck Institute of Biochemistry, Martinsried, Germany; Faculty of Physics, Ludwig Maximilian University, Munich, Germany
| | - Michael B. Elowitz
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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3
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Yeni YN, Oravec D, Drost J, Zauel R, Flynn MJ. Stiffness and Strain Properties Derived From Digital Tomosynthesis-Based Digital Volume Correlation Predict Vertebral Strength Independently From Bone Mineral Density. J Biomech Eng 2023; 145:041009. [PMID: 36350266 PMCID: PMC9791669 DOI: 10.1115/1.4056196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Vertebral fractures are the most common osteoporotic fractures, but their prediction using standard bone mineral density (BMD) measurements from dual energy X-ray absorptiometry (DXA) is limited in accuracy. Stiffness, displacement, and strain distribution properties derived from digital tomosynthesis-based digital volume correlation (DTS-DVC) have been suggested as clinically measurable metrics of vertebral bone quality. However, the extent to which these properties correlate to vertebral strength is unknown. To establish this relationship, two independent experiments, one examining isolated T11 and the other examining L3 vertebrae within the L2-L4 segments from cadaveric donors were utilized. Following DXA and DTS imaging, the specimens were uniaxially compressed to fracture. BMD, bone mineral content (BMC), and bone area were recorded for the anteroposterior and lateromedial views from DXA, stiffness, endplate to endplate displacement and distribution statistics of intravertebral strains were calculated from DTS-DVC and vertebral strength was measured from mechanical tests. Regression models were used to examine the relationships of strength with the other variables. Correlations of BMD with vertebral strength varied between experimental groups (R2adj = 0.19-0.78). DTS-DVC derived properties contributed to vertebral strength independently from BMD measures (increasing R2adj to 0.64-0.95). DTS-DVC derived stiffness was the best single predictor (R2adj = 0.66, p < 0.0001) and added the most to BMD in models of vertebral strength for pooled T11 and L3 specimens (R2adj = 0.95, p < 0.0001). These findings provide biomechanical relevance to DTS-DVC calculated properties of vertebral bone and encourage further efforts in the development of the DTS-DVC approach as a clinical tool.
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Affiliation(s)
- Yener N. Yeni
- Bone & Joint Center, Henry Ford Hospital Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Daniel Oravec
- Bone & Joint Center, Henry Ford Hospital Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Joshua Drost
- Bone & Joint Center, Henry Ford Hospital Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Roger Zauel
- Bone & Joint Center, Henry Ford Hospital Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Michael J. Flynn
- Department of Radiology, Henry Ford Hospital, One Ford Place, Suite 2F, Detroit, MI 48202
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Flynn MJ, Ledermann JA. Ovarian cancer recurrence: is the definition of platinum resistance modified by PARPi and other intervening treatments? The evolving landscape in the management of platinum-resistant ovarian cancer. Cancer Drug Resist 2022; 5:424-435. [PMID: 35800366 PMCID: PMC9255242 DOI: 10.20517/cdr.2022.13] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/30/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022]
Abstract
Definitions of platinum resistance have been questioned and changed over the last five years, even though no predictive biomarker of resistance exists. These have sculpted how we approach platinum retreatment and, consequently, how we devise new treatment strategies for those patients with tumour progression on platinum therapy. Platinum-non-eligible ovarian cancer is treated with single-agent non-platinum drugs. When bevacizumab can be added to chemotherapy, progression-free survival improves significantly. For patients with a BRCA mutation, PARP inhibitor monotherapy is an option compared to chemotherapy. There is currently no clearly identified role for immune-checkpoint inhibition in this patient population. This review describes some of the challenges in treating patients with platinum resistance and suggests refinements in the selection of patients most likely to benefit from targeting a DNA damage response, angiogenesis or immune modulation. It also describes novel agents of interest and possible mechanisms of the synergy of therapeutic combinations.
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Affiliation(s)
- Michael J. Flynn
- Department of Oncology, University College London Hospital, London NW1 2PG, United Kingdom
| | - Jonathan A. Ledermann
- Department of Oncology, University College London Hospital, London NW1 2PG, United Kingdom
- UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
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Yeni YN, Dix MR, Xiao A, Oravec DJ, Flynn MJ. Measuring the thickness of vertebral endplate and shell using digital tomosynthesis. Bone 2022; 157:116341. [PMID: 35092890 PMCID: PMC8858866 DOI: 10.1016/j.bone.2022.116341] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 12/07/2021] [Accepted: 01/23/2022] [Indexed: 02/05/2023]
Abstract
The vertebral endplate and cortical shell play an important structural role and contribute to the overall strength of the vertebral body, are at highest risk of initial failure, and are involved in degenerative disease of the spine. The ability to accurately measure the thickness of these structures is therefore important, even if difficult due to relatively low resolution clinical imaging. We posit that digital tomosynthesis (DTS) may be a suitable imaging modality for measurement of endplate and cortical shell thickness owing to the ability to reconstruct multiplanar images with good spatial resolution at low radiation dose. In this study, for 25 cadaveric L1 vertebrae, average and standard deviation of endplate and cortical shell thickness were measured using images from DTS and microcomputed tomography (μCT). For endplate thickness measurements, significant correlations between DTS and μCT were found for all variables when comparing thicknesses measured in both the overall endplate volume (R2 = 0.25-0.54) and when measurements were limited to a central range of coronal or sagittal slices (R2 = 0.24-0.62). When compared to reference values from the overall shell volume, DTS thickness measurements were generally nonsignificant. However, when measurement of cortical shell thickness was limited to a range of central slices, DTS outcomes were significantly correlated with reference values for both sagittal and coronal central regions (R2 = 0.21-0.49). DTS may therefore offer a means for measurement of endplate thickness and, within a limited sagittal or coronal measurement volume, for measurement of cortical shell thickness.
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Affiliation(s)
- Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America.
| | - Michael R Dix
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America; School of Medicine, Wayne State University, Detroit, MI, United States of America
| | - Angela Xiao
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
| | - Daniel J Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
| | - Michael J Flynn
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
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6
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Oravec D, Kim W, Flynn MJ, Yeni YN. The Relationship of Whole Human Vertebral Body Creep to Bone Density and Texture via Clinically Available Imaging Modalities. J Biomech 2022; 135:111021. [PMID: 35245836 PMCID: PMC9064953 DOI: 10.1016/j.jbiomech.2022.111021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 11/30/2021] [Accepted: 02/21/2022] [Indexed: 11/30/2022]
Abstract
Creep deformation of human vertebrae accumulates under physiological levels of load and is understood to contribute to the progression toward clinically observable vertebral fracture. However, little information is available in terms of clinically measurable predictors of creep behavior in human vertebrae. In this study, creep tests were performed on 22 human cadaveric T12 vertebrae (13 male, 9 female; age 41-90). Areal and volumetric bone density parameters were measured from the same specimens using dual x-ray absorptiometry and high resolution computed tomography. Image textural analyses (which probe the organization of image intensities within the cancellous bone in low resolution clinical imaging) were performed using digital tomosynthesis (DTS) images. Multiple regression models were constructed to examine the relationship between creep properties and bone density and DTS image textural parameters. For the standard clinical imaging configuration, models including DTS derived image textural parameters alone were generally more explanatory (adjusted R2: 0.14-0.68) than those with bone density parameters forced in the models (adjusted R2: 0.17-0.61). Metrics of textural heterogeneity and anisotropy presented as the most explanatory imaging markers for creep deformation and recovery from creep. These metrics of image texture may help provide, independent from bone mass, important clinically measurable indicators of the time dependent deformation of human vertebrae.
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Affiliation(s)
- Daniel Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Woong Kim
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Michael J Flynn
- Department of Radiology, Henry Ford Hospital, Detroit, MI, United States
| | - Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States.
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7
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Wilgus ML, Abtin F, Markovic D, Tashkin DP, Phillips JE, Buhr RG, Flynn MJ, Dembek M, Cooper CB, Barjaktarevic I. Panlobular emphysema is associated with COPD disease severity: A study of emphysema subtype by computed tomography. Respir Med 2021; 192:106717. [PMID: 35026616 DOI: 10.1016/j.rmed.2021.106717] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/30/2021] [Accepted: 12/12/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Computed tomography has the potential to inform COPD prognosis. We sought to determine associations of emphysema phenotype with clinical parameters including lung function, inflammatory markers, and quality of life. METHODS Participants of this single-center observational cohort (n = 83) were 40-80 years old, had ≥10 pack-year smoking, and a diagnosis of COPD confirmed by spirometry. All participants had available historic chest CT scans which were systematically reviewed by a single expert radiologist and scored for emphysema subtype, extent, and distribution. Associations between radiographic findings and clinical parameters were determined. RESULTS Median age of participants was 72 years, median smoking 40 pack-years, and median FEV1 59% predicted. 84% of the participants had radiographic emphysema. Of those, 26% had panlobular emphysema (PLE), 68% centrilobular emphysema (CLE), and 6% paraseptal emphysema (PSE). As compared to the participants with no radiographic emphysema, the presence of PLE-dominant emphysema was associated with a lower BMI (P = 0.012) and greater extent of emphysema (P = 0.014). After adjusting for age, sex, and pack-years smoking history, PLE was associated with greater airflow obstruction by FEV1% (48% vs 71%, P = 0.005), greater symptom burden by CAT score (18 vs 9, P = 0.015), worse quality of life by SGRQ score (43 vs 22, P = 0.025), and more systemic inflammation by erythrocyte sedimentation rate (P = 0.001). CLE- or PSE-dominant emphysema were not similarly associated with clinical features or symptom burden. CONCLUSIONS The presence of PLE-dominant emphysema was associated with greater extent of emphysema, greater airflow obstruction, increased respiratory symptoms, worse quality of life, and systemic inflammation. Further investigation is indicated to explore the pathogenesis of the PLE phenotype and the prognostic and treatment implications of PLE.
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Affiliation(s)
- M L Wilgus
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - F Abtin
- Division of Thoracic Radiology, Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - D Markovic
- Department of Medicine Statistics Core, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - D P Tashkin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - J E Phillips
- Inflammation Discovery Research, Amgen, Thousand Oaks, CA, USA
| | - R G Buhr
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA; Department of Medicine, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA
| | - M J Flynn
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA; Division of Pulmonology, Kaiser Permanente Sunnyside Medical Center, Clackamas, OR, USA
| | - M Dembek
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA; Department of Physician Assistant Studies, Bay Path University, Longmeadow, MA, USA
| | - C B Cooper
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA; Department of Physiology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - I Barjaktarevic
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA.
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8
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Akay M, Funingana IG, Patel G, Mustapha R, Gjafa E, Ng T, Ng K, Flynn MJ. An In-Depth Review of Niraparib in Ovarian Cancer: Mechanism of Action, Clinical Efficacy and Future Directions. Oncol Ther 2021; 9:347-364. [PMID: 34363200 PMCID: PMC8593085 DOI: 10.1007/s40487-021-00167-z] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/22/2021] [Indexed: 01/24/2023] Open
Abstract
Niraparib is an oral, potent, highly selective poly-ADP ribose polymerase 1 (PARP1) and PARP2 inhibitor. In most developed countries, it is approved as a maintenance treatment for epithelial ovarian, fallopian tube, or primary peritoneal cancer in patients with complete or partial response to platinum-based therapy. These approvals are based on results of randomised, double-blind, placebo-controlled trials, particularly the NOVA trial and more recently the PRIMA trial. In this comprehensive review, we delve into the scientific basis of PARP inhibition, discussing both preclinical and clinical data which have led to the current approval status of niraparib. We also discuss ongoing trials and biological rationale of combination treatments involving niraparib, with particular focus on antiangiogenic drugs, immune checkpoint inhibitors and cyclic GMP-AMP synthase stimulator of interferon genes (cGAS/STING) pathway. In addition, we reflect on potential strategies and challenges of utilising current biomarkers for treatment selection of patients to ensure maximal benefit.
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Affiliation(s)
- Melek Akay
- Department of Medical Oncology, St George's University Hospitals NHS Foundation Trust, London, UK
| | | | - Grisma Patel
- Department of Medical Oncology, University College London Hospitals, London, UK
| | - Rami Mustapha
- School of Cancer and Pharmaceutical Sciences, King's College London, London, UK
- Cancer Research UK King's Health Partners Centre, London, UK
| | - Ernese Gjafa
- Department of Medical Oncology, Barts Health NHS Trust, London, UK
| | - Tony Ng
- School of Cancer and Pharmaceutical Sciences, King's College London, London, UK
- Cancer Research UK King's Health Partners Centre, London, UK
- Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Kenrick Ng
- Department of Medical Oncology, University College London Hospitals, London, UK.
- Cancer Institute, University College London, 72 Huntley Street, London, UK.
| | - Michael J Flynn
- Department of Medical Oncology, University College London Hospitals, London, UK
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Oravec D, Drost J, Zauel R, Flynn MJ, Yeni YN. Assessment of Intravertebral Mechanical Strains and Cancellous Bone Texture Under Load Using a Clinically Available Digital Tomosynthesis Modality. J Biomech Eng 2021; 143:1109661. [PMID: 34041529 DOI: 10.1115/1.4051280] [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: 12/15/2020] [Indexed: 11/08/2022]
Abstract
Vertebral fractures are the most common osteoporotic fractures, but clinical means for assessment of vertebral bone integrity are limited in accuracy, as they typically use surrogate measures that are indirectly related to mechanics. The objective of this study was to examine the extent to which intravertebral strain distributions and changes in cancellous bone texture generated by a load of physiological magnitude can be characterized using a clinically available imaging modality. We hypothesized that digital tomosynthesis-based digital volume correlation (DTS-DVC) and image texture-based metrics of cancellous bone microstructure can detect development of mechanical strains under load. Isolated cadaveric T11 vertebrae and L2-L4 vertebral segments were DTS imaged in a nonloaded state and under physiological load levels. Axial strain, maximum principal strain, maximum compressive and tensile principal strains, and von Mises equivalent strain were calculated using the DVC technique. The change in textural parameters (line fraction deviation, anisotropy, and fractal parameters) under load was calculated within the cancellous centrum. The effect of load on measured strains and texture variables was tested using mixed model analysis of variance, and relationships of strain and texture variables with donor age, bone density parameters, and bone size were examined using regression models. Magnitudes and heterogeneity of intravertebral strain measures correlated with applied loading and were significantly different from background noise. Image texture parameters were found to change with applied loading, but these changes were not observed in the second experiment testing L2-L4 segments. DTS-DVC-derived strains correlated with age more strongly than did bone mineral density (BMD) for T11.
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Affiliation(s)
- Daniel Oravec
- Bone & Joint Center, Henry Ford Hospital, Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Joshua Drost
- Bone & Joint Center, Henry Ford Hospital, Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Roger Zauel
- Bone & Joint Center, Henry Ford Hospital, Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
| | - Michael J Flynn
- Department of Radiology, Henry Ford Hospital, One Ford Place, Suite 2F, Detroit, MI 48202
| | - Yener N Yeni
- Bone & Joint Center, Henry Ford Hospital, Integrative Biosciences Center (iBio), 6135 Woodward, Detroit, MI 48202
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10
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Yeni YN, Oravec D, Drost J, Bevins N, Morrison C, Flynn MJ. Bone health assessment via digital wrist tomosynthesis in the mammography setting. Bone 2021; 144:115804. [PMID: 33321264 DOI: 10.1016/j.bone.2020.115804] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/05/2020] [Accepted: 12/10/2020] [Indexed: 11/26/2022]
Abstract
Bone fractures attributable to osteoporosis are a significant problem. Though preventative treatment options are available for individuals who are at risk of a fracture, a substantial number of these individuals are not identified due to lack of adherence to bone screening recommendations. The issue is further complicated as standard diagnosis of osteoporosis is based on bone mineral density (BMD) derived from dual energy x-ray absorptiometry (DXA), which, while helpful in identifying many at risk, is limited in fully predicting risk of fracture. It is reasonable to expect that bone screening would become more prevalent and efficacious if offered in coordination with digital breast tomosynthesis (DBT) exams, provided that osteoporosis can be assessed using a DBT modality. Therefore, the objective of the current study was to explore the feasibility of using digital tomosynthesis imaging in a mammography setting. To this end, we measured density, cortical thickness and microstructural properties of the wrist bone, correlated these to reference measurements from microcomputed tomography and DXA, demonstrated the application in vivo in a small group of participants, and determined the repeatability of the measurements. We found that measurements from digital wrist tomosynthesis (DWT) imaging with a DBT scanner were highly repeatable ex vivo (error = 0.05%-9.62%) and in vivo (error = 0.06%-10.2%). In ex vivo trials, DWT derived BMDs were strongly correlated with reference measurements (R = 0.841-0.980), as were cortical thickness measured at lateral and medial cortices (R = 0.991 and R = 0.959, respectively) and the majority of microstructural measures (R = 0.736-0.991). The measurements were quick and tolerated by human patients with no discomfort, and appeared to be different between young and old participants in a preliminary comparison. In conclusion, DWT is feasible in a mammography setting, and informative on bone mass, cortical thickness, and microstructural qualities that are known to deteriorate in osteoporosis. To our knowledge, this study represents the first application of DBT for imaging bone. Future clinical studies are needed to further establish the efficacy for diagnosing osteoporosis and predicting risk of fragility fracture using DWT.
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Affiliation(s)
- Yener N Yeni
- Bone and Joint Center, Henry Ford Health System, Detroit, MI, USA.
| | - Daniel Oravec
- Bone and Joint Center, Henry Ford Health System, Detroit, MI, USA
| | - Joshua Drost
- Bone and Joint Center, Henry Ford Health System, Detroit, MI, USA
| | - Nicholas Bevins
- Department of Radiology, Henry Ford Health System, Detroit, MI, USA
| | | | - Michael J Flynn
- Department of Radiology, Henry Ford Health System, Detroit, MI, USA
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Bevins NB, Silosky MS, Badano A, Marsh RM, Flynn MJ, Walz-Flannigan AI. Practical application of AAPM Report 270 in display quality assurance: A report of Task Group 270. Med Phys 2020; 47:e920-e928. [PMID: 32681556 DOI: 10.1002/mp.14227] [Citation(s) in RCA: 7] [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] [Received: 01/16/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 11/07/2022] Open
Abstract
Published in January 2019, AAPM Report 270 provides an update to the recommendations of the AAPM's "TG18" report. Report 270 provides new definitions of display types, updated testing patterns, and revised performance standards for the modern, flat-panel displays used as part of medical image acquisition and review. The focus of the AAPM report is on consistent image quality and appearance, and how to establish a quality assurance program to achieve those two goals. This work highlights some of the key takeaways of AAPM Report 270 and makes comparisons with existing recommendations from other references. It also provides guidance for establishing a display quality assurance program for different-sized institutions. Finally, it describes future challenges for display quality assurance and what work remains.
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Affiliation(s)
- Nicholas B Bevins
- Department of Radiology, Henry Ford Health System, Detroit, MI, 48202, USA
| | - Michael S Silosky
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Aldo Badano
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Rebecca M Marsh
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Michael J Flynn
- Public Health Sciences, Henry Ford Health System, Detroit, MI, 48202, USA
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12
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Oravec D, Flynn MJ, Zauel R, Rao S, Yeni YN. Digital tomosynthesis based digital volume correlation: A clinically viable noninvasive method for direct measurement of intravertebral displacements using images of the human spine under physiological load. Med Phys 2019; 46:4553-4562. [PMID: 31381174 DOI: 10.1002/mp.13750] [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] [Received: 02/19/2019] [Revised: 06/17/2019] [Accepted: 07/26/2019] [Indexed: 01/23/2023] Open
Abstract
PURPOSE We have developed a clinically viable method for measurement of direct, patient-specific intravertebral displacements using a novel digital tomosynthesis based digital volume correlation technique. These displacements may be used to calculate vertebral stiffness under loads induced by a patient's body weight; this is particularly significant because, among biomechanical variables, stiffness is the strongest correlate of bone strength. In this proof of concept study, we assessed the feasibility of the method through a preliminary evaluation of the accuracy and precision of the method, identification of a range of physiological load levels for which displacements are measurable, assessment of the relationship of measured displacements with microcomputed tomography based standards, and demonstration of the in vivo application of the technique. METHODS Five cadaveric T11 vertebrae were allocated to three groups in order to study (a) the optimization of digital volume correlation algorithm input parameters, (b) accuracy and precision of the method and the ability to measure displacements at a range of physiological load levels, and (c) the correlation between displacements measured using tomosynthesis based digital volume correlation vs. high resolution microcomputed tomography based digital volume correlation and large scale finite element models. Tomosynthesis images of one patient (Female, 60 yr old) were used to calculate displacement maps, and in turn stiffness, using images acquired in both standing and standing-with-weight (8 kg) configurations. RESULTS We found that displacements were accurate (2.28 µm total error) and measurable at physiological load levels (above 267 N) with a linear response to applied load. Calculated stiffness among three tested vertebral bodies was within an acceptable range relative to reported values for vertebral stiffness (5651-13260 N/mm). Displacements were in good qualitative and quantitative agreement with both microcomputed tomography based finite element (r2 = 0.762, P < 0.001) and digital volume correlation (r2 = 0.799, P < 0.001) solutions. For one patient tested twice, once standing and once holding weights, results demonstrated excellent qualitative reproducibility of displacement distributions with superior endplate displacements increasing by 22% with added weight. CONCLUSIONS The results of this work collectively suggest the feasibility of the method for in vivo measurement of intravertebral displacements and stiffness in humans. These findings suggest that digital volume correlation using digital tomosynthesis imaging may be useful in understanding the mechanical response of bone to disease and may further enhance our ability to assess fracture risk and treatment efficacy for the spine.
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Affiliation(s)
- Daniel Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA
| | - Michael J Flynn
- Department of Radiology, Henry Ford Hospital, Detroit, MI, USA
| | - Roger Zauel
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA
| | - Sudhaker Rao
- Department of Endocrinology, Henry Ford Hospital, Detroit, MI, USA
| | - Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA
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Flynn MJ, Sayed AA, Sharma R, Siddique A, Pinato DJ. Challenges and Opportunities in the Clinical Development of Immune Checkpoint Inhibitors for Hepatocellular Carcinoma. Hepatology 2019; 69:2258-2270. [PMID: 30382576 DOI: 10.1002/hep.30337] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Abstract
After a decade of stagnation in drug development, therapeutic reversal of immune-exhaustion with immune checkpoint inhibitors (ICPIs) has been shown to be effective in advanced hepatocellular carcinoma (HCC). The clinical development of novel ICPIs continues at a rapid pace, with more than 50 clinical trials of immunotherapeutic agents registered as of May 2018 for this indication. The development of ICPI is particularly challenging in patients with HCC, a population with unique features which impact on safety and efficacy of immune-modulating therapies. In this review, we discuss the biological foundations supporting the development of ICPIs across the advancing stages of HCC, focusing on the rational positioning of ICPIs across the various Barcelona-Clinic Liver Cancer (BCLC) stages of the disease. Translational studies should guide adequate prioritization of those therapeutic agents and combination strategies which are most likely to achieve patient benefit based on solid mechanistic and clinical justifications.
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Affiliation(s)
- Michael J Flynn
- Department of Medicine, The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Anwar A Sayed
- Centre for Haematology, Imperial College London, London, United Kingdom
- Department of Medical Microbiology and Immunology, Taibah University, Medina, Saudi Arabia
| | - Rohini Sharma
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Abdul Siddique
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - David J Pinato
- Department of Surgery & Cancer, Imperial College London, Hammersmith Hospital, London, United Kingdom
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14
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Lusk CM, Wenzlaff AS, Watza D, Sieren JC, Robinette N, Walworth G, Petrich M, Neslund-Dudas C, Flynn MJ, Song T, Spizarny D, Simoff MJ, Soubani AO, Gadgeel S, Schwartz AG. Quantitative Imaging Markers of Lung Function in a Smoking Population Distinguish COPD Subgroups with Differential Lung Cancer Risk. Cancer Epidemiol Biomarkers Prev 2019; 28:724-730. [PMID: 30642838 DOI: 10.1158/1055-9965.epi-18-0886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/30/2018] [Accepted: 12/12/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition with respect to onset, progression, and response to therapy. Incorporating clinical- and imaging-based features to refine COPD phenotypes provides valuable information beyond that obtained from traditional clinical evaluations. We characterized the spectrum of COPD-related phenotypes in a sample of former and current smokers and evaluated how these subgroups differ with respect to sociodemographic characteristics, COPD-related comorbidities, and subsequent risk of lung cancer. METHODS White (N = 659) and African American (N = 520) male and female participants without lung cancer (controls) in the INHALE study who completed a chest CT scan, interview, and spirometry test were used to define distinct COPD-related subgroups based on hierarchical clustering. Seven variables were used to define clusters: pack years, quit years, FEV1/FVC, % predicted FEV1, and from quantitative CT (qCT) imaging, % emphysema, % air trapping, and mean lung density ratio. Cluster definitions were then applied to INHALE lung cancer cases (N = 576) to evaluate lung cancer risk. RESULTS Five clusters were identified that differed significantly with respect to sociodemographic (e.g., race, age) and clinical (e.g., BMI, limitations due to breathing difficulties) characteristics. Increased risk of lung cancer was associated with increasingly detrimental lung function clusters (when ordered from most detrimental to least detrimental). CONCLUSIONS Measures of lung function vary considerably among smokers and are not fully explained by smoking intensity. IMPACT Combining clinical (spirometry) and radiologic (qCT) measures of COPD defines a spectrum of lung disease that predicts lung cancer risk differentially among patient clusters.
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Affiliation(s)
- Christine M Lusk
- Karmanos Cancer Institute, Detroit, Michigan.,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan
| | - Angela S Wenzlaff
- Karmanos Cancer Institute, Detroit, Michigan.,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan
| | - Donovan Watza
- Karmanos Cancer Institute, Detroit, Michigan.,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan
| | - Jessica C Sieren
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Natasha Robinette
- Department of Radiology, Karmanos Cancer Institute, Detroit, Michigan
| | - Garrett Walworth
- Department of Radiology, Karmanos Cancer Institute, Detroit, Michigan
| | - Michael Petrich
- Department of Radiology, Karmanos Cancer Institute, Detroit, Michigan
| | - Christine Neslund-Dudas
- Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan.,Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan
| | - Michael J Flynn
- Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan.,Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - Thomas Song
- Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - David Spizarny
- Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan.,Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - Michael J Simoff
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan.,Division of Pulmonary and Critical Care Medicine, Henry Ford Health System, Detroit, Michigan
| | - Ayman O Soubani
- Karmanos Cancer Institute, Detroit, Michigan.,Department of Internal Medicine, School of Medicine, Wayne State University, Detroit, Michigan
| | - Shirish Gadgeel
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Ann G Schwartz
- Karmanos Cancer Institute, Detroit, Michigan. .,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan
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15
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Yeni YN, Kim W, Oravec D, Nixon M, Divine GW, Flynn MJ. Assessment of vertebral wedge strength using cancellous textural properties derived from digital tomosynthesis and density properties from dual energy X-ray absorptiometry and high resolution computed tomography. J Biomech 2018; 79:191-197. [PMID: 30173933 DOI: 10.1016/j.jbiomech.2018.08.019] [Citation(s) in RCA: 6] [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: 03/26/2018] [Revised: 07/31/2018] [Accepted: 08/13/2018] [Indexed: 01/23/2023]
Abstract
The purpose of this study was to examine the potential of digital tomosynthesis (DTS) derived cancellous bone textural measures to predict vertebral strength under conditions simulating a wedge fracture. 40 vertebral bodies (T6, T8, T11, and L3 levels) from 5 male and 5 female cadaveric donors were utilized. The specimens were scanned using dual energy X-ray absorptiometry (DXA) and high resolution computed tomography (HRCT) to obtain measures of bone mineral density (BMD) and content (BMC), and DTS to obtain measures of bone texture. Using a custom loading apparatus designed to deliver a nonuniform displacement resulting in a wedge deformity similar to those observed clinically, the specimens were loaded to fracture and their fracture strength was recorded. Mixed model regressions were used to determine the associations between wedge strength and DTS derived textural variables, alone and in the presence of BMD or BMC information. DTS derived fractal, lacunarity and mean intercept length variables correlated with wedge strength, and individually explained up to 53% variability. DTS derived textural variables, notably fractal dimension and lacunarity, contributed to multiple regression models of wedge strength independently from BMC and BMD. The model from a scan orientation transverse to the spine axis and in the anterior-posterior view resulted in highest explanatory capability (R2adj = 0.91), with a scan orientation parallel to the spine axis and in the lateral view offering an alternative (R2adj = 0.88). In conclusion, DTS can be used to examine cancellous texture relevant to vertebral wedge strength, and potentially complement BMD in assessment of vertebral fracture risk.
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Affiliation(s)
- Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States.
| | - Woong Kim
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Daniel Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Mary Nixon
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - George W Divine
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Michael J Flynn
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
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16
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Hartley JA, Flynn MJ, Bingham JP, Corbett S, Reinert H, Tiberghien A, Masterson LA, Antonow D, Adams L, Chowdhury S, Williams DG, Mao S, Harper J, Havenith CEG, Zammarchi F, Chivers S, van Berkel PH, Howard PW. Pre-clinical pharmacology and mechanism of action of SG3199, the pyrrolobenzodiazepine (PBD) dimer warhead component of antibody-drug conjugate (ADC) payload tesirine. Sci Rep 2018; 8:10479. [PMID: 29992976 PMCID: PMC6041317 DOI: 10.1038/s41598-018-28533-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/22/2018] [Indexed: 01/12/2023] Open
Abstract
Synthetic pyrrolobenzodiazepine (PBD) dimers, where two PBD monomers are linked through their aromatic A-ring phenolic C8-positions via a flexible propyldioxy tether, are highly efficient DNA minor groove cross-linking agents with potent cytotoxicity. PBD dimer SG3199 is the released warhead component of the antibody-drug conjugate (ADC) payload tesirine (SG3249), currently being evaluated in several ADC clinical trials. SG3199 was potently cytotoxic against a panel of human solid tumour and haematological cancer cell lines with a mean GI50 of 151.5 pM. Cells defective in DNA repair protein ERCC1 or homologous recombination repair showed increased sensitivity to SG3199 and the drug was only moderately susceptible to multidrug resistance mechanisms. SG3199 was highly efficient at producing DNA interstrand cross-links in naked linear plasmid DNA and dose-dependent cross-linking was observed in cells. Cross-links formed rapidly in cells and persisted over 36 hours. Following intravenous (iv) administration to rats SG3199 showed a very rapid clearance with a half life as short as 8 minutes. These combined properties of cytotoxic potency, rapid formation and persistence of DNA interstrand cross-links and very short half-life contribute to the emerging success of SG3199 as a warhead in clinical stage ADCs.
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Affiliation(s)
- John A Hartley
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6BT, UK. .,Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK.
| | - Michael J Flynn
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6BT, UK
| | - John P Bingham
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6BT, UK
| | - Simon Corbett
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6BT, UK.,Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Halla Reinert
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, 72 Huntley Street, London, WC1E 6BT, UK
| | - Arnaud Tiberghien
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Luke A Masterson
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Dyeison Antonow
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Lauren Adams
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Sajidah Chowdhury
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - David G Williams
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Shenlan Mao
- MedImmune, One MedImmune Way, Gaithersburg, MD, 20878, USA
| | - Jay Harper
- MedImmune, One MedImmune Way, Gaithersburg, MD, 20878, USA
| | - Carin E G Havenith
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Francesca Zammarchi
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Simon Chivers
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Patrick H van Berkel
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
| | - Philip W Howard
- Spirogen Ltd, QMB Innovation Centre, 42 New Road, London, E1 2AX, UK
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17
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Oravec D, Kim W, Flynn MJ, Yeni YN. The relationship of whole human vertebral body creep to geometric, microstructural, and material properties. J Biomech 2018; 73:92-98. [PMID: 29599039 DOI: 10.1016/j.jbiomech.2018.03.021] [Citation(s) in RCA: 10] [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: 10/05/2017] [Revised: 02/02/2018] [Accepted: 03/09/2018] [Indexed: 12/15/2022]
Abstract
Creep, the time dependent deformation of a structure under load, is an important viscoelastic property of bone and may play a role in the development of permanent deformity of the vertebrae in vivo leading to clinically observable spinal fractures. To date, creep properties and their relationship to geometric, microstructural, and material properties have not been described in isolated human vertebral bodies. In this study, a range of image-based measures of vertebral bone geometry, bone mass, microarchitecture and mineralization were examined in multiple regression models in an effort to understand their contribution to creep behavior. Several variables, such as measures of mineralization heterogeneity, average bone density, and connectivity density persistently appeared as significant effects in multiple regression models (adjusted r2: 0.17-0.56). Although further work is needed to identify additional tissue properties to fully describe the portion of variability not explained by these models, these data are expected to help understand mechanisms underlying creep and improve prediction of vertebral deformities that eventually progress to a clinically observable fracture.
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Affiliation(s)
- Daniel Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Woong Kim
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Michael J Flynn
- Department of Radiology, Henry Ford Hospital, Detroit, MI, United States
| | - Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States.
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18
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Samei E, Ikejimba LC, Harrawood BP, Rong J, Cunningham IA, Flynn MJ. Report of AAPM Task Group 162: Software for planar image quality metrology. Med Phys 2018; 45:e32-e39. [DOI: 10.1002/mp.12718] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/31/2017] [Accepted: 11/30/2017] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories; Medical Physics Graduate Program; Departments of Radiology, Biomedical Engineering, Physics, and Electrical and Computer Engineering; Clinical Imaging Physics Group; Duke University; 2424 Erwin Road Durham NC 27710 USA
| | - Lynda C. Ikejimba
- Carl E. Ravin Advanced Imaging Laboratories; Medical Physics Graduate Program; Department of Radiology; Duke University; 2424 Erwin Road Durham NC 27710 USA
| | - Brian P. Harrawood
- Carl E. Ravin Advanced Imaging Laboratories; Department of Radiology; Duke University; 2424 Erwin Road Durham NC 27710 USA
| | - John Rong
- Department of Imaging Physics; UT MD Anderson Cancer Center; 1400 Pressler St, Unit 1472 Houston TX 77030 USA
| | - Ian A. Cunningham
- Robarts Research Institute; Western University; 1151 Richmind St N London ON N6A 5B7 Canada
| | - Michael J. Flynn
- Department of Diagnostic Radiology; Henry Ford Health System; One Ford Pl, 3F Detroit MI 48202 USA
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Abstract
CD25 (also termed IL2RA) forms one component of the high-affinity heterotrimeric interleukin 2 (IL2) receptor on activated T cells. Its affinity for IL2 and cellular function are tightly regulated and vary in different cell types. The high frequency of CD25 on the surface of many different haematological tumour cells is now well established and, apart from its prognostic significance, CD25 may be present on leukaemic stem cells and enable oncogenic signalling pathways in leukaemic cells. Additionally, high CD25 expression in activated circulating immune cells and Tregs is a factor that has already been exploited by IL2 immunotherapies for treatment of tumours and autoimmune disease. The relative clinical safety and efficacy of administering anti-CD25 radioimmunoconjugates and immunotoxins in various haematological tumour indications has been established and clinical trials of a novel CD25-directed antibody drug conjugate are underway.
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20
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Flynn MJ, Larkin JM. Novel combination strategies for enhancing efficacy of immune checkpoint inhibitors in the treatment of metastatic solid malignancies. Expert Opin Pharmacother 2017; 18:1477-1490. [DOI: 10.1080/14656566.2017.1369956] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Michael J. Flynn
- Department of Medical Oncology, Royal Marsden Hospital, London, United Kingdom
| | - James M.G. Larkin
- Department of Medical Oncology, Royal Marsden Hospital, London, United Kingdom
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21
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Lee C, Flynn MJ, Judy PF, Cody DD, Bolch WE, Kruger R. Body Size-Specific Organ and Effective Doses of Chest CT Screening Examinations of the National Lung Screening Trial. AJR Am J Roentgenol 2017; 208:1082-1088. [PMID: 28267354 PMCID: PMC10774020 DOI: 10.2214/ajr.16.16979] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [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] [Indexed: 11/18/2022]
Abstract
OBJECTIVE We calculated body size-specific organ and effective doses for 23,734 participants in the National Lung Screening Trial (NLST) using a CT dose calculator. MATERIALS AND METHODS We collected participant-specific technical parameters of 23,734 participants who underwent CT in the clinical trial. For each participant, we calculated two sets of organ doses using two methods. First, we computed body size-specific organ and effective doses using the National Cancer Institute CT (NCICT) dosimetry program, which is based on dose coefficients derived from a library of body size-dependent adult male and female computational phantoms. We then recalculated organ and effective doses using dose coefficients from reference size phantoms for all examinations to investigate potential errors caused by the lack of body size consideration in the dose calculations. RESULTS The underweight participants (body mass index [BMI; weight in kilograms divided by the square of height in meters] < 18.5) received 1.3-fold greater lung dose (median, 4.93 mGy) than the obese participants (BMI > 30) (3.90 mGy). Thyroid doses were approximately 1.3- to 1.6-fold greater than the lung doses (6.3-6.5 mGy). The reference phantom-based dose calculation underestimates the body size-specific lung dose by up to 50% for the underweight participants and overestimates that value by up to 200% for the overweight participants. The median effective dose ranges from 2.01 mSv in obese participants to 2.80 mSv in underweight participants. CONCLUSION Body size-specific organ and effective doses were computed for 23,734 NLST participants who underwent low-dose CT screening. The use of reference size phantoms can lead to significant errors in organ dose estimates when body size is not considered in the dose assessment.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health
| | | | - Phillip F. Judy
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA
| | - Dianna D. Cody
- Department of Imaging Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX
| | - Wesley E. Bolch
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
| | - Randell Kruger
- System Radiology, Marshfield Clinic Health System, Marshfield, WI
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Neiworth JJ, London JM, Flynn MJ, Rupert DD, Alldritt O, Hyde C. Artificial grammar learning in tamarins (Saguinus oedipus) in varying stimulus contexts. ACTA ACUST UNITED AC 2017; 131:128-138. [PMID: 28277720 DOI: 10.1037/com0000066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human ability to detect regularities in sound sequences is a fundamental substrate of our language faculty. However, is this an ability exclusive to human language processing, or have we usurped a more general learning mechanism for this purpose, one shared with other species? The current study is an attempt to replicate and extend Hauser, Weiss, and Marcus's (2002) retracted study (2010) of artificial grammar learning in tamarins to determine if tamarins can detect an underlying grammatical structure in a pattern of sounds. Human language consonant-vowel (CV) combinations from Hauser et al.'s original study, newly created tone sequences, and newly created monkey vocalizations made into sequences were used to familiarize tamarins to an AAB or ABB pattern. Tests of novel sounds in each condition were presented that either were consistent with the familiarized pattern or were different from it. Longer looking times toward the sound source (an audio speaker with a specific location in the auditory field) indicated recognition of novelty. Tamarins looked toward the speaker significantly longer with inconsistent human language CV sequences and with inconsistent tone sequences but not when an inconsistent monkey vocalization was presented. Moreover, tamarins showed differential rates of habituation to the different types of sound patterns, with more robust habituation to CV sequences and tone sequences than to monkey call sequences. The implications of these findings for the generality of learning mechanisms for linguistic and nonlinguistic input across species and the importance of testing across various stimuli are discussed. (PsycINFO Database Record
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Affiliation(s)
| | | | | | | | | | - Caleb Hyde
- Department of Psychology, Carleton College
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23
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Kim W, Oravec D, Divine GW, Flynn MJ, Yeni YN. Effect of View, Scan Orientation and Analysis Volume on Digital Tomosynthesis (DTS) Based Textural Analysis of Bone. Ann Biomed Eng 2017; 45:1236-1246. [DOI: 10.1007/s10439-017-1792-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
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24
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Flynn MJ, Zammarchi F, Tyrer PC, Akarca AU, Janghra N, Britten CE, Havenith CEG, Levy JN, Tiberghien A, Masterson LA, Barry C, D'Hooge F, Marafioti T, Parren PWHI, Williams DG, Howard PW, van Berkel PH, Hartley JA. ADCT-301, a Pyrrolobenzodiazepine (PBD) Dimer-Containing Antibody-Drug Conjugate (ADC) Targeting CD25-Expressing Hematological Malignancies. Mol Cancer Ther 2016; 15:2709-2721. [PMID: 27535974 DOI: 10.1158/1535-7163.mct-16-0233] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/13/2016] [Indexed: 11/16/2022]
Abstract
Despite the many advances in the treatment of hematologic malignancies over the past decade, outcomes in refractory lymphomas remain poor. One potential strategy in this patient population is the specific targeting of IL2R-α (CD25), which is overexpressed on many lymphoma and leukemic cells, using antibody-drug conjugates (ADC). ADCT-301 is an ADC composed of human IgG1 HuMax-TAC against CD25, stochastically conjugated through a dipeptide cleavable linker to a pyrrolobenzodiazepine (PBD) dimer warhead with a drug-antibody ratio (DAR) of 2.3. ADCT-301 binds human CD25 with picomolar affinity. ADCT-301 has highly potent and selective cytotoxicity against a panel of CD25-expressing human lymphoma cell lines. Once internalized, the released warhead binds in the DNA minor groove and exerts its potent cytotoxic action via the formation of DNA interstrand cross-links. A strong correlation between loss of viability and DNA cross-link formation is demonstrated. DNA damage persists, resulting in phosphorylation of histone H2AX, cell-cycle arrest in G2-M, and apoptosis. Bystander killing of CD25-negative cells by ADCT-301 is also observed. In vivo, a single dose of ADCT-301 results in dose-dependent and targeted antitumor activity against both subcutaneous and disseminated CD25-positive lymphoma models. In xenografts of Karpas 299, which expressed both CD25 and CD30, marked superiority over brentuximab vedotin (Adcetris) is observed. Dose-dependent increases in DNA cross-linking, γ-H2AX, and PBD payload staining were observed in tumors in vivo indicating a role as relevant pharmacodynamic assays. Together, these data support the clinical testing of this novel ADC in patients with CD25-expressing tumors. Mol Cancer Ther; 15(11); 2709-21. ©2016 AACR.
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Affiliation(s)
- Michael J Flynn
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, London, United Kingdom
- Spirogen Ltd, QMB Innovation Centre, London, United Kingdom
| | - Francesca Zammarchi
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, London, United Kingdom
| | - Peter C Tyrer
- Spirogen Ltd, QMB Innovation Centre, London, United Kingdom
| | - Ayse U Akarca
- Department of Pathology, University College London, London, United Kingdom
| | - Narinder Janghra
- Department of Pathology, University College London, London, United Kingdom
| | - Charles E Britten
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, London, United Kingdom
| | - Carin E G Havenith
- ADC Therapeutics (UK) Limited, QMB Innovation Centre, London, United Kingdom
| | - Jean-Noel Levy
- Spirogen Ltd, QMB Innovation Centre, London, United Kingdom
| | | | | | - Conor Barry
- Spirogen Ltd, QMB Innovation Centre, London, United Kingdom
| | | | - Teresa Marafioti
- Department of Pathology, University College London, London, United Kingdom
| | - Paul W H I Parren
- Genmab, Utrecht, the Netherlands
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | | | - John A Hartley
- Cancer Research UK Drug DNA Interactions Research Group, UCL Cancer Institute, London, United Kingdom.
- Spirogen Ltd, QMB Innovation Centre, London, United Kingdom
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Schwartz AG, Lusk CM, Wenzlaff AS, Watza D, Pandolfi S, Mantha L, Cote ML, Soubani AO, Walworth G, Wozniak A, Neslund-Dudas C, Ardisana AA, Flynn MJ, Song T, Spizarny DL, Kvale PA, Chapman RA, Gadgeel SM. Risk of Lung Cancer Associated with COPD Phenotype Based on Quantitative Image Analysis. Cancer Epidemiol Biomarkers Prev 2016; 25:1341-7. [PMID: 27383774 DOI: 10.1158/1055-9965.epi-16-0176] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/31/2016] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is a risk factor for lung cancer. This study evaluates alternative measures of COPD based on spirometry and quantitative image analysis to better define a phenotype that predicts lung cancer risk. METHODS A total of 341 lung cancer cases and 752 volunteer controls, ages 21 to 89 years, participated in a structured interview, standardized CT scan, and spirometry. Logistic regression, adjusted for age, race, gender, pack-years, and inspiratory and expiratory total lung volume, was used to estimate the odds of lung cancer associated with FEV1/FVC, percent voxels less than -950 Hounsfield units on the inspiratory scan (HUI) and percent voxels less than -856 HU on expiratory scan (HUE). RESULTS The odds of lung cancer were increased 1.4- to 3.1-fold among those with COPD compared with those without, regardless of assessment method; however, in multivariable modeling, only percent voxels <-856 HUE as a continuous measure of air trapping [OR = 1.04; 95% confidence interval (CI), 1.03-1.06] and FEV1/FVC < 0.70 (OR = 1.71; 95% CI, 1.21-2.41) were independent predictors of lung cancer risk. Nearly 10% of lung cancer cases were negative on all objective measures of COPD. CONCLUSION Measures of air trapping using quantitative imaging, in addition to FEV1/FVC, can identify individuals at high risk of lung cancer and should be considered as supplementary measures at the time of screening for lung cancer. IMPACT Quantitative measures of air trapping based on imaging provide additional information for the identification of high-risk groups who might benefit the most from lung cancer screening. Cancer Epidemiol Biomarkers Prev; 25(9); 1341-7. ©2016 AACR.
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Affiliation(s)
- Ann G Schwartz
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan.
| | - Christine M Lusk
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Angela S Wenzlaff
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Donovan Watza
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Stephanie Pandolfi
- Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | | | - Michele L Cote
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Ayman O Soubani
- Karmanos Cancer Institute, Detroit, Michigan. Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Garrett Walworth
- Department of Radiology, Karmanos Cancer Institute, Detroit, Michigan
| | - Antoinette Wozniak
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Christine Neslund-Dudas
- Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan. Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan
| | - Amy A Ardisana
- Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan. Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan
| | - Michael J Flynn
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan. Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - Thomas Song
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan. Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - David L Spizarny
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan. Department of Radiology, Henry Ford Health System, Detroit, Michigan
| | - Paul A Kvale
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan. Department of Pulmonary and Critical Care Medicine, Henry Ford Health System, Detroit, Michigan
| | - Robert A Chapman
- Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, Michigan. Department of Hematology/Oncology, Henry Ford Health System, Detroit, Michigan
| | - Shirish M Gadgeel
- Karmanos Cancer Institute, Detroit, Michigan. Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
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Badano A, Wang J, Boynton P, Le Callet P, Cheng WC, Deroo D, Flynn MJ, Matsui T, Penczek J, Revie C, Samei E, Steven PM, Swiderski S, Van Hoey G, Yamaguchi M, Hasegawa M, Nagy BV. Technical Note: Gray tracking in medical color displays-A report of Task Group 196. Med Phys 2016; 43:4017. [DOI: 10.1118/1.4953186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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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Oravec D, Quazi A, Xiao A, Yang E, Zauel R, Flynn MJ, Yeni YN. Digital tomosynthesis and high resolution computed tomography as clinical tools for vertebral endplate topography measurements: Comparison with microcomputed tomography. Bone 2015. [PMID: 26220145 PMCID: PMC4640984 DOI: 10.1016/j.bone.2015.07.033] [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] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Endplate morphology is understood to play an important role in the mechanical behavior of vertebral bone as well as degenerative processes in spinal tissues; however, the utility of clinical imaging modalities in assessment of the vertebral endplate has been limited. The objective of this study was to evaluate the ability of two clinical imaging modalities (digital tomosynthesis, DTS; high resolution computed tomography, HRCT) to assess endplate topography by correlating the measurements to a microcomputed tomography (μCT) standard. DTS, HRCT, and μCT images of 117 cadaveric thoracolumbar vertebrae (T10-L1; 23 male, 19 female; ages 36-100 years) were segmented, and inferior and superior endplate surface topographical distribution parameters were calculated. Both DTS and HRCT showed statistically significant correlations with μCT approaching a moderate level of correlation at the superior endplate for all measured parameters (R(2)Adj=0.19-0.57), including averages, variability, and higher order statistical moments. Correlation of average depths at the inferior endplate was comparable to the superior case for both DTS and HRCT (R(2)Adj=0.14-0.51), while correlations became weak or nonsignificant for higher moments of the topography distribution. DTS was able to capture variations in the endplate topography to a slightly better extent than HRCT, and taken together with the higher speed and lower radiation cost of DTS than HRCT, DTS appears preferable for endplate measurements.
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Affiliation(s)
- Daniel Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Abrar Quazi
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Angela Xiao
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Ellen Yang
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Roger Zauel
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
| | - Michael J Flynn
- Department of Radiology, Henry Ford Hospital, Detroit, MI, United States
| | - Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States
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Hirschorn DS, Krupinski EA, Flynn MJ. PACS Displays: How to Select the Right Display Technology. J Am Coll Radiol 2014; 11:1270-6. [DOI: 10.1016/j.jacr.2014.09.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
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Stavraka C, Pinato DJ, Turnbull SJ, Flynn MJ, Forster MD, O'Cathail SM, Babar S, Seckl MJ, Kristeleit RS, Blagden SP. Developing an objective marker to optimize patient selection and predict survival benefit in early-phase cancer trials. Cancer 2013; 120:262-70. [PMID: 24399418 DOI: 10.1002/cncr.28381] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [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: 05/24/2013] [Revised: 08/16/2013] [Accepted: 08/20/2013] [Indexed: 11/08/2022]
Abstract
BACKGROUND Several prognostic indices have been devised to optimize patient selection for phase 1 oncology trials with no consensus as to the optimal score and none qualifying as a marker of treatment response. METHODS Multivariate predictors of overall survival (OS) were tested on 118 referred patients to develop the Hammersmith Score (HS). The score's ability to predict OS, progression-free survival (PFS), and 90-day mortality (90DM) was compared with other prognostic indices. Changes in HS were recalculated during treatment. RESULTS Albumin<35 g/L, lactate dehydrogenase>450 U/L, and sodium<135 mmol/L emerged as independent prognostic factors. These were used with equal weighting to devise the HS, a compound prognostic index ranging from 0 to 3. High (HS=2-3) score predicted worse OS (hazard ratio [HR]=6.5, P<.001), PFS (HR=2.8, P=.01), and 90DM (OR=9.0, P<.001). HS was a more accurate multivariate predictor of OS (HR=6.4, P<.001, C-index=0.72), PFS (HR=2.7, P=.03), and 90DM (area under the ROC curve 0.703) compared with other scores. Worsening of the HS during treatment predicted for shorter OS (P<.001). HS retained prognostic and predictive ability following external validation. CONCLUSIONS HS is a simple, validated index to optimize patient selection and predict survival benefit from phase 1 oncology treatments. Prospective validation is ongoing.
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Affiliation(s)
- Chara Stavraka
- Department of Experimental Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
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30
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Andriole KP, Ruckdeschel TG, Flynn MJ, Hangiandreou NJ, Jones AK, Krupinski E, Seibert JA, Shepard SJ, Walz-Flannigan A, Mian TA, Pollack MS. ACR-AAPM-SIIM practice guideline for digital radiography. J Digit Imaging 2013; 26:26-37. [PMID: 22992867 DOI: 10.1007/s10278-012-9523-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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31
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Miglioretti DL, Johnson E, Williams A, Greenlee RT, Weinmann S, Solberg LI, Feigelson HS, Roblin D, Flynn MJ, Vanneman N, Smith-Bindman R. The use of computed tomography in pediatrics and the associated radiation exposure and estimated cancer risk. JAMA Pediatr 2013; 167:700-7. [PMID: 23754213 PMCID: PMC3936795 DOI: 10.1001/jamapediatrics.2013.311] [Citation(s) in RCA: 922] [Impact Index Per Article: 83.8] [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: 12/13/2022]
Abstract
IMPORTANCE Increased use of computed tomography (CT) in pediatrics raises concerns about cancer risk from exposure to ionizing radiation. OBJECTIVES To quantify trends in the use of CT in pediatrics and the associated radiation exposure and cancer risk. DESIGN Retrospective observational study. SETTING Seven US health care systems. PARTICIPANTS The use of CT was evaluated for children younger than 15 years of age from 1996 to 2010, including 4 857 736 child-years of observation. Radiation doses were calculated for 744 CT scans performed between 2001 and 2011. MAIN OUTCOMES AND MEASURES Rates of CT use, organ and effective doses, and projected lifetime attributable risks of cancer. RESULTS The use of CT doubled for children younger than 5 years of age and tripled for children 5 to 14 years of age between 1996 and 2005, remained stable between 2006 and 2007, and then began to decline. Effective doses varied from 0.03 to 69.2 mSv per scan. An effective dose of 20 mSv or higher was delivered by 14% to 25% of abdomen/pelvis scans, 6% to 14% of spine scans, and 3% to 8% of chest scans. Projected lifetime attributable risks of solid cancer were higher for younger patients and girls than for older patients and boys, and they were also higher for patients who underwent CT scans of the abdomen/pelvis or spine than for patients who underwent other types of CT scans. For girls, a radiation-induced solid cancer is projected to result from every 300 to 390 abdomen/pelvis scans, 330 to 480 chest scans, and 270 to 800 spine scans, depending on age. The risk of leukemia was highest from head scans for children younger than 5 years of age at a rate of 1.9 cases per 10 000 CT scans. Nationally, 4 million pediatric CT scans of the head, abdomen/pelvis, chest, or spine performed each year are projected to cause 4870 future cancers. Reducing the highest 25% of doses to the median might prevent 43% of these cancers. CONCLUSIONS AND RELEVANCE The increased use of CT in pediatrics, combined with the wide variability in radiation doses, has resulted in many children receiving a high-dose examination. Dose-reduction strategies targeted to the highest quartile of doses could dramatically reduce the number of radiation-induced cancers.
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Affiliation(s)
- Diana L. Miglioretti
- Biostatistics Unit, Group Health Research Institute,
Seattle, WA,Department of Biostatistics, University of Washington,
Seattle, WA
| | - Eric Johnson
- Biostatistics Unit, Group Health Research Institute,
Seattle, WA
| | - Andrew Williams
- Center for Health Research, Kaiser Permanente Hawaii,
Honolulu, HI
| | - Robert T. Greenlee
- Epidemiology Research Center, Marshfield Clinic Research
Foundation, Marshfield, WI
| | - Sheila Weinmann
- Center for Health Research, Kaiser Permanente Northwest,
Portland, OR
| | | | | | - Douglas Roblin
- Center for Health Research, Kaiser Permanente Southeast,
Atlanta, GA
| | | | - Nicholas Vanneman
- Institute of General Practice, Johann Wolfgang
Goethe-University, Frankfurt, Germany
| | - Rebecca Smith-Bindman
- Department of Radiology and Biomedical Imaging,
University of California, San Francisco, CA,Department of Epidemiology and Biostatistics, University
of California, San Francisco, CA,Department of Obstetrics, Gynecology and Reproductive
Sciences, University of California, San Francisco, CA
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Kruger R, Flynn MJ, Judy PF, Cagnon CH, Seibert JA. Effective dose assessment for participants in the National Lung Screening Trial undergoing posteroanterior chest radiographic examinations. AJR Am J Roentgenol 2013; 201:142-6. [PMID: 23789668 PMCID: PMC3743238 DOI: 10.2214/ajr.12.9181] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [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] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The National Lung Screening Trial (NLST) is a multicenter randomized controlled trial comparing low-dose helical CT with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004, when 53,454 participants had been randomized at 33 screening sites. The objective of this study was to determine the effective radiation dose associated with individual chest radiographic screening examinations. SUBJECTS AND METHODS A total of 73,733 chest radiographic examinations were performed with 92 chest imaging systems. The entrance skin air kerma (ESAK) of participants' chest radiographic examinations was estimated and used in this analysis. The effective dose per ESAK for each examination was determined with a Monte Carlo-based program. The examination effective dose was calculated as the product of the examination ESAK and the Monte Carlo estimate of the ratio of effective dose per ESAK. RESULTS This study showed that the mean effective dose assessed from 66,157 postero-anterior chest examinations was 0.052 mSv. Additional findings were a median effective dose of 0.038 mSv, a 95th percentile value of 0.136 mSv, and a fifth percentile value of 0.013 mSv. CONCLUSION The effective dose for participant NLST chest radiographic examinations was determined and is of specific interest in relation to that associated with the previously published NLST low-dose CT examinations conducted during the trial.
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Affiliation(s)
- Randell Kruger
- Department of Radiology, Medical Physics Section, Marshfield Clinic, 1000 N Oak Ave, Marshfield, WI 54449-5777, USA.
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Yeni YN, Poisson LM, Flynn MJ. Heterogeneity of bone mineral density and fatigue failure of human vertebrae. J Biomech 2013; 46:1396-9. [PMID: 23538003 DOI: 10.1016/j.jbiomech.2013.02.015] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 02/07/2013] [Accepted: 02/26/2013] [Indexed: 11/30/2022]
Abstract
There is increasing interest in using the heterogeneity of tissue properties in a bone for predicting its fracture risk. Heterogeneity of volumetric bone mineral density (BMD) as measured from quantitative computed tomography (QCT) is of particular interest as these measurements are clinically feasible. Previous examinations of the relationship between the BMD heterogeneity and the mechanical behavior of human vertebrae only considered quasistatic strength and were with limited number of samples. McCubbrey et al. (1995) studied the value of regional BMDs for predicting vertebral fatigue life, determined from short-cycle tests at force levels scaled with the estimated strength of the vertebra, but the focus of that work was in best predictor subsets without a specific focus on the heterogeneity of BMD or the positive vs negative direction of the relationships. The previous analysis also did not take into account the censored nature of the fatigue life data. As such, whether BMD heterogeneity is positively or negatively associated with fatigue life and whether this is independent of the average or minimum BMD are not clear. In the present work, we revisited the McCubbrey data for a preliminary examination of the relationship between BMD heterogeneity and fatigue life using survival analysis. The analysis suggests that BMD heterogeneity measured as the intra-vertebral standard deviation of BMDs in a vertebra is negatively associated with short cycle (high-amplitude) fatigue life independent of the average BMD. The results motivate further studies on the role of BMD heterogeneity in fatigue failure and clinical fracture risk of human vertebrae.
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Affiliation(s)
- Yener N Yeni
- Section of Biomechanics, Bone and Joint Center, Henry Ford Hospital, Henry Ford Health System, 2799 West Grand Boulevard Detroit, MI, 48202-2689 USA.
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Altman MB, Flynn MJ, Nishikawa RM, Chetty IJ, Barton KN, Movsas B, Kim JH, Brown SL. The potential of iodine for improving breast cancer diagnosis and treatment. Med Hypotheses 2012; 80:94-8. [PMID: 23171625 DOI: 10.1016/j.mehy.2012.10.018] [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] [Received: 05/28/2012] [Revised: 10/12/2012] [Accepted: 10/28/2012] [Indexed: 11/25/2022]
Abstract
Early detection through modalities such as mammography remains pivotal in the fight against breast cancer. The detectability of breast cancer through mammography is rooted in the differential X-ray attenuation properties of cancerous and normal breast tissue. An unexplored component of the X-ray contrast between fibrous breast tissue and similarly composed tumor tissue is the presence of naturally localized iodine in the cancer but not healthy breast tissue. It is hypothesized that differing amounts of iodine are present in tumor versus normal breast tissue that leads to more easily detectable cancer due to an increased Z value of the tumor tissue relative to the healthy tissue, which results in enhanced differences in X-ray attenuation properties between the two tissues and thus greater radiographic contrast. The hypothesis is supported by experimental observations explaining how iodine could localize in the tumor tissue but not surrounding healthy tissue. Breast cancer cells express the sodium-iodide symporter (NIS), an ion pump which sequesters iodine in tumor cells. Healthy non-lactating breast tissue, in contrast, does not express NIS. Further evidence for the differential expression of NIS resulting in X-ray contrast enhancement in breast cancer is the established correlation between expression of insulin growth factor (IGF) and enhanced X-ray contrast, and the evidence that IGF is a promoter for NIS. Ultimately, if the expression of iodine can be shown to be a component of radiographic contrast between healthy and tumor breast tissue, this could be used to drive the development of new technology and techniques for use in the detection and treatment of breast cancer. The proof of this hypothesis could thus have a substantial impact in the fight against breast cancer.
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Affiliation(s)
- Michael B Altman
- Henry Ford Health System, Department of Radiation Oncology, 2799 W. Grand Blvd., Detroit, MI 48202, USA.
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Flynn MJ. President's report on process and progress at the MDA. Northwest Dent 2012; 91:6-48. [PMID: 23346652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Gazaille RE, Flynn MJ, Page W, Finley S, van Holsbeeck M. Technical innovation: digital tomosynthesis of the hip following intra-articular administration of contrast. Skeletal Radiol 2011; 40:1467-71. [PMID: 21822939 DOI: 10.1007/s00256-011-1247-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [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] [Received: 04/09/2011] [Revised: 07/01/2011] [Accepted: 07/25/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To demonstrate the clinical use of digital tomosynthesis in the depiction of labral and chondral pathology in the setting of post-operative CAM-type impingement of the hip following intra-articular administration of dilute iodinated contrast. MATERIALS AND METHODS We present images from a 46 year-old African American female with suspected CAM-type femoroacetabular impingement (FAI) following percutaneous pinning of the right hip for slipped capital femoral epiphysis (SCFE). RESULTS A partial tear of the labrum and clinically significant acetabular chondral abnormalities were demonstrated with the use of digital tomosynthesis with superb anatomic detail. CONCLUSION Digital tomosynthesis can be of great clinical utility and can depict pathology in superb anatomic detail, particularly in situations in which MRI is not available as well as under circumstances in which artifact due to orthopedic hardware is of concern as shown in this case.
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Affiliation(s)
- Roland E Gazaille
- Department of Musculoskeletal Radiology, Henry Ford Hospital, Detroit, MI 48202, USA.
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Pedicord DL, Flynn MJ, Fanslau C, Miranda M, Hunihan L, Robertson BJ, Pearce BC, Yu XC, Westphal RS, Blat Y. Molecular characterization and identification of surrogate substrates for diacylglycerol lipase α. Biochem Biophys Res Commun 2011; 411:809-14. [PMID: 21787747 DOI: 10.1016/j.bbrc.2011.07.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 12/12/2022]
Abstract
Diacylglycerol lipase α is the key enzyme in the formation of the most prevalent endocannabinoid, 2-arachidonoylglycerol in the brain. In this study we identified the catalytic triad of diacylglycerol lipase α, consisting of serine 472, aspartate 524 and histidine 650. A truncated version of diacylglycerol lipase α, spanning residues 1-687 retains complete catalytic activity suggesting that the C-terminal domain is not required for catalysis. We also report the discovery and the characterization of fluorogenic and chromogenic substrates for diacylglycerol lipase α. Assays performed with these substrates demonstrate equipotent inhibition of diacylglycerol lipase α by tetrahydrolipastatin and RHC-20867 as compared to reactions performed with the native diacylglycerol substrate. Thus, confirming the utility of assays using these substrates for identification and kinetic characterization of inhibitors from pharmaceutical collections.
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Affiliation(s)
- Donna L Pedicord
- Department of Mechanistic Biochemistry, Bristol-Myers Squibb Company, Princeton, NJ 08543, USA
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Cody DD, Kim HJ, Cagnon CH, Larke FJ, McNitt-Gray MM, Kruger RL, Flynn MJ, Seibert JA, Judy PF, Wu X. Normalized CT dose index of the CT scanners used in the National Lung Screening Trial. AJR Am J Roentgenol 2010; 194:1539-46. [PMID: 20489094 PMCID: PMC3015146 DOI: 10.2214/ajr.09.3268] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The National Lung Screening Trial includes 33 participating institutions that performed 75,133 lung cancer screening CT examinations for 26,724 subjects during 2002-2007. For trial quality assurance reasons, CT radiation dose measurement data were collected from all MDCT scanners used in the trial. MATERIALS AND METHODS A total of 247 measurements on 96 MDCT scanners were collected using a standard CT dose index (CTDI) measurement protocol. The scan parameters used in the measurements (tube voltage, milliampere-seconds [mAs], and detector-channel configuration) were set according to trial protocol for average size subjects. The normalized weighted CT dose index (CTDI(w)) (computed as CTDI(w)/mAs) obtained from each trial-participating scanner was tabulated. RESULTS We found a statistically significant difference in normalized CT dose index among CT scanner manufacturers, likely as a result of design differences, such as filtration, bow-tie design, and geometry. Our findings also indicated a statistically significant difference in normalized CT dose index among CT scanner models from the same manufacturer (e.g., GE Healthcare, Siemens Healthcare, and Philips Healthcare). We also found a statistically significant difference in normalized CT dose index among all models and all manufacturers; furthermore, we found a statistically significant difference in normalized CT dose index among CT scanners from all manufacturers when we compared scanners with four or eight data channels to those with 16, 32, or 64 channels, suggesting that more complex scanners have improved dose efficiency. CONCLUSION Average normalized CT dose index values varied by a factor of almost two for all scanners from all manufacturers. This study was focused on machine-specific normalized CT dose index; patient dose and image quality were not addressed.
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Affiliation(s)
- Dianna D Cody
- Department of Imaging Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
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Hamilton JF, Allen G, Watson NM, Lee JD, Saxton JE, Lewis AC, Vaughan G, Bower KN, Flynn MJ, Crosier J, Carver GD, Harris NRP, Parker RJ, Remedios JJ, Richards NAD. Observations of an atmospheric chemical equator and its implications for the tropical warm pool region. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jd009940] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [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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Fetterly KA, Blume HR, Flynn MJ, Samei E. Introduction to grayscale calibration and related aspects of medical imaging grade liquid crystal displays. J Digit Imaging 2008; 21:193-207. [PMID: 17333412 PMCID: PMC3043865 DOI: 10.1007/s10278-007-9022-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Consistent presentation of digital radiographic images at all locations within a medical center can help ensure a high level of patient care. Currently, liquid crystal displays (LCDs) are the electronic display technology of choice for viewing medical images. As the inherent luminance (and thereby perceived contrast) properties of different LCDs can vary substantially, calibration of the luminance response of these displays is required to ensure that observer perception of an image is consistent on all displays. The digital imaging and communication in medicine (DICOM) grayscale standard display function (GSDF) defines the luminance response of a display such that an observer's perception of image contrast is consistent throughout the pixel value range of a displayed image. The main purpose of this work is to review the theoretical and practical aspects of calibration of LCDs to the GSDF. Included herein is a review of LCD technology, principles of calibration, and other practical aspects related to calibration and observer perception of images presented on LCDs. Both grayscale and color displays are considered, and the influence of ambient light on calibration and perception is discussed.
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Affiliation(s)
- Kenneth A Fetterly
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota, USA.
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Affiliation(s)
- Charles E Kahn
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA.
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Sahni-Arya B, Flynn MJ, Bergeron L, Salyan MEK, Pedicord DL, Golla R, Ma Z, Wang H, Seethala R, Wu SC, Li JJ, Nayeem A, Gates C, Hamann LG, Gordon DA, Blat Y. Cofactor-specific modulation of 11beta-hydroxysteroid dehydrogenase 1 inhibitor potency. Biochim Biophys Acta 2007; 1774:1184-91. [PMID: 17707701 DOI: 10.1016/j.bbapap.2007.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/05/2007] [Accepted: 07/11/2007] [Indexed: 11/19/2022]
Abstract
11beta-hydroxysteroid dehydrogenase 1 regulates the tissue availability of cortisol by interconverting cortisone and cortisol. It is capable of functioning as both a reductase and a dehydrogenase depending upon the surrounding milieu. In this work, we have studied the reaction mechanism of a soluble form of human 11beta-hydroxysteroid dehydrogenase 1 and its mode of inhibition by potent and selective inhibitors belonging to three different structural classes. We found that catalysis follows an ordered addition with NADP(H) binding preceding the binding of the steroid. While all three inhibitors tested bound to the steroid binding pocket, they differed in their interactions with the cofactor NADP(H). Compound A, a pyridyl amide bound more efficiently to the NADPH-bound form of 11beta-hydroxysteroid dehydrogenase 1. Compound B, an adamantyl triazole, was unaffected by NADP(H) binding and the sulfonamide, Compound C, showed preferential binding to the NADP+ -bound form of 11beta-hydroxysteroid dehydrogenase 1. These differences were found to augment significant selectivity towards inhibition of the reductase reaction versus the dehydrogenase reaction. This selectivity may translate to differences in the in vivo effects of 11beta-hydroxysteroid dehydrogenase 1 inhibitors.
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Affiliation(s)
- Bhavana Sahni-Arya
- Department of Chemical Enzymology, Bristol-Myers Squibb, 311 Pennington-Rocky Hill Rd., Pennington, NJ 08534, USA
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Brown SL, Freytag SO, Barton KN, Flynn MJ, Peck DJ, Dragovic AF, Jin R, Yeni YN, Fyhrie DP, Les CM, Zhu G, Kolozsvary A, Pitchford WC, Nathanson SD, Fenstermacher JD, Kim JH. Reporter gene imaging using radiographic contrast from nonradioactive iodide sequestered by the sodium–iodide symporter. Contrast Media Mol Imaging 2007; 2:240-7. [DOI: 10.1002/cmmi.150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Flynn MJ, McComb JM, Dark JH. Reply to Fernández et al. Eur J Cardiothorac Surg 2006. [DOI: 10.1016/j.ejcts.2005.12.037] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Flynn MJ, McComb JM, Dark JH. Temporary left ventricular pacing improves haemodynamic performance in patients requiring epicardial pacing post cardiac surgery. Eur J Cardiothorac Surg 2005; 28:250-3. [PMID: 15923120 DOI: 10.1016/j.ejcts.2005.03.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [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] [Received: 12/09/2004] [Revised: 03/12/2005] [Accepted: 03/14/2005] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE In the 1990s, sequential atrio-ventricular pacing demonstrated haemodynamic benefit relative to right ventricular pacing in patients with sinus rhythm requiring pacing post cardiopulmonary bypass. The benefit of biventricular pacing has been demonstrated in non-surgical patients with severe left ventricular dysfunction. It was hypothesised that left ventricular pacing would increase cardiac output in surgical patients. We report the findings of a prospective trial of left ventricular pacing with active lead placement on the anterior or posterior left ventricular surface, compared to standard practice of active lead placement on the right ventricular surface. METHODS Twenty five patients with left ventricular dysfunction underwent pacing with active lead placement on the right ventricle (control), the anterior left ventricle and the posterior left ventricle in random order, with each pacing mode of 10 min duration, following cardiopulmonary bypass. Haemodynamic parameters were measured with a thermodilution pulmonary artery catheter. Patients provided their control values. RESULTS In the 25 patients studied, pacing with the active lead posteriorly on the left ventricle increased cardiac index from 2.74 to 3.08 l/min per m2 (P=0.019). Significant increases in mean arterial pressure with the use of this pacing mode were observed. There were no complications relating to application or removal of the left ventricle pacing leads. CONCLUSIONS Left ventricular pacing with active lead placed on the postero-lateral left ventricular wall affords haemodynamic benefit to cardiac surgical patients.
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Affiliation(s)
- Michael J Flynn
- Department of Cardiothoracic Surgery, Freeman Hospital, Newcastle-on-Tyne, NE7 7DN, UK.
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Samei E, Badano A, Chakraborty D, Compton K, Cornelius C, Corrigan K, Flynn MJ, Hemminger B, Hangiandreou N, Johnson J, Moxley-Stevens DM, Pavlicek W, Roehrig H, Rutz L, Shepard J, Uzenoff RA, Wang J, Willis CE. Assessment of display performance for medical imaging systems: Executive summary of AAPM TG18 report. Med Phys 2005; 32:1205-25. [PMID: 15895604 DOI: 10.1118/1.1861159] [Citation(s) in RCA: 241] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Digital imaging provides an effective means to electronically acquire, archive, distribute, and view medical images. Medical imaging display stations are an integral part of these operations. Therefore, it is vitally important to assure that electronic display devices do not compromise image quality and ultimately patient care. The AAPM Task Group 18 (TG18) recently published guidelines and acceptance criteria for acceptance testing and quality control of medical display devices. This paper is an executive summary of the TG18 report. TG18 guidelines include visual, quantitative, and advanced testing methodologies for primary and secondary class display devices. The characteristics, tested in conjunction with specially designed test patterns (i.e., TG18 patterns), include reflection, geometric distortion, luminance, the spatial and angular dependencies of luminance, resolution, noise, glare, chromaticity, and display artifacts. Geometric distortions are evaluated by linear measurements of the TG18-QC test pattern, which should render distortion coefficients less than 2%/5% for primary/secondary displays, respectively. Reflection measurements include specular and diffuse reflection coefficients from which the maximum allowable ambient lighting is determined such that contrast degradation due to display reflection remains below a 20% limit and the level of ambient luminance (Lamb) does not unduly compromise luminance ratio (LR) and contrast at low luminance levels. Luminance evaluation relies on visual assessment of low contrast features in the TG18-CT and TG18-MP test patterns, or quantitative measurements at 18 distinct luminance levels of the TG18-LN test patterns. The major acceptable criteria for primary/ secondary displays are maximum luminance of greater than 170/100 cd/m2, LR of greater than 250/100, and contrast conformance to that of the grayscale standard display function (GSDF) of better than 10%/20%, respectively. The angular response is tested to ascertain the viewing cone within which contrast conformance to the GSDF is better than 30%/60% and LR is greater than 175/70 for primary/secondary displays, or alternatively, within which the on-axis contrast thresholds of the TG18-CT test pattern remain discernible. The evaluation of luminance spatial uniformity at two distinct luminance levels across the display faceplate using TG18-UNL test patterns should yield nonuniformity coefficients smaller than 30%. The resolution evaluation includes the visual scoring of the CX test target in the TG18-QC or TG18-CX test patterns, which should yield scores greater than 4/6 for primary/secondary displays. Noise evaluation includes visual evaluation of the contrast threshold in the TG18-AFC test pattern, which should yield a minimum of 3/2 targets visible for primary/secondary displays. The guidelines also include methodologies for more quantitative resolution and noise measurements based on MTF and NPS analyses. The display glare test, based on the visibility of the low-contrast targets of the TG18-GV test pattern or the measurement of the glare ratio (GR), is expected to yield scores greater than 3/1 and GRs greater than 400/150 for primary/secondary displays. Chromaticity, measured across a display faceplate or between two display devices, is expected to render a u',v' color separation of less than 0.01 for primary displays. The report offers further descriptions of prior standardization efforts, current display technologies, testing prerequisites, streamlined procedures and timelines, and TG18 test patterns.
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Affiliation(s)
- Ehsan Samei
- Duke Advanced Imaging Laboratories, Department of Radiology, Duke University, DUMC 3302, Durham, North Carolina 27710, USA.
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Flynn MJ, Rassl D, El Shahira A, Higgins B, Barnard S. Metachronous and Synchronous Lung Tumors: Five Malignant Lung Pathologies in 1 Patient During 7 Years. Ann Thorac Surg 2004; 78:2154-5. [PMID: 15561057 DOI: 10.1016/s0003-4975(03)01514-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [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] [Accepted: 07/29/2003] [Indexed: 01/03/2023]
Abstract
We present the case of a 70-year-old man who previously had a left upper lobectomy for nonsmall cell lung carcinoma that subsequently developed into small cell carcinoma, which was successfully treated, and finally he had a right upper lobectomy that revealed three synchronous lung malignancies. We were unable to find a previous case report with a total of five separate lung malignancies with a combination of metachronous and synchronous tumors. This case demonstrates the importance of screening after the diagnosis and treatment of lung carcinoma.
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MESH Headings
- Adenocarcinoma/diagnostic imaging
- Adenocarcinoma/pathology
- Aged
- Carcinoid Tumor/pathology
- Carcinoma, Non-Small-Cell Lung/surgery
- Carcinoma, Small Cell/surgery
- Carcinoma, Squamous Cell/diagnostic imaging
- Carcinoma, Squamous Cell/pathology
- Humans
- Lung Neoplasms/diagnostic imaging
- Lung Neoplasms/pathology
- Lung Neoplasms/surgery
- Male
- Neoplasms, Multiple Primary/diagnostic imaging
- Neoplasms, Multiple Primary/pathology
- Neoplasms, Multiple Primary/surgery
- Neoplasms, Second Primary/diagnostic imaging
- Neoplasms, Second Primary/pathology
- Neoplasms, Second Primary/surgery
- Pneumonectomy
- Radiography
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Affiliation(s)
- Michael J Flynn
- Department of Cardiothoracic Surgery, Freeman Hospital, Newcastle-on-Tyne, Newcastle-on-Tyne, United Kingdom.
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Abstract
Active-matrix liquid crystal displays (AMLCDs) are light-modulating devices that generate images by differentially transmitting a nearly uniform luminous field provided by a backlight. While emissive displays exhibit a quasi-Lambertian emission with almost constant contrast at off-normal viewing, the anisotropy of the electro-optic effect that controls light transmission in AMLCDs causes a pixel luminance that varies, sometimes strongly, with viewing angle. These variations are not identical for all gray levels and can eventually cause grayscale inversions. In this paper, we measured the luminance emission of a monochrome medical AMLCD, a medical cathode-ray tube monitor, and a color desktop AMLCD, using a collimated photopic probe positioned on a manual rotation arm, and a research radiometer with automatic readout. The probe measures luminance with a small acceptance angle and provides optical shielding from emissions at other viewing directions that contaminate the readings. We obtained luminance response curves versus angle in the vertical, horizontal and at 45 degrees diagonal directions. The display systems were calibrated to reflect the DICOM Part 3.14 standard grayscale display function (GDF) when measured using the manufacturer's probe and software tools. We analyzed the measurements at different viewing directions with respect to their departure from the GDF by computing the normalized contrast (deltaL/L) as a function of the DICOM just-noticeable difference index. Although cathode-ray tubes are known to be quasi-Lambertian emitters, the luminance at normal viewing is higher than the luminance observed at large angles. This decrease in luminance is however proportionally similar for all gray levels, resulting in a relatively flat contrast response for all angles. In addition to being more pronounced, the angular variation in AMLCDs does not follow the same profile at different intensities with the subsequent variation in the achieved display contrast. The changes due to off-normal viewing are substantial at large angles in the horizontal and vertical directions, and much worse in the diagonal viewing directions.
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Affiliation(s)
- Aldo Badano
- Center for Devices and Radiological Health, Food and Drug Administration, 12720 Twinbrook Parkway, Rockville, Maryland 20857, USA.
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Samei E, Seibert JA, Andriole K, Badano A, Crawford J, Reiner B, Flynn MJ, Chang P. AAPM/RSNA Tutorial on Equipment Selection: PACS Equipment Overview. Radiographics 2004; 24:313-34. [PMID: 14730055 DOI: 10.1148/rg.241035137] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A picture archiving and communication system (PACS) is a comprehensive computer system that is responsible for the electronic storage and distribution of medical images in the medical enterprise. The system is highly integrated with digital acquisition and display devices and is often related closely to other medical information systems, such as the radiology information system or hospital information system. In the past few years, there has been continuous growth in clinical implementation of PACS to reduce costs and improve patient care, a trend that is expected to continue. However, a PACS is complex and costly to acquire, replace, maintain, and repair. To select a system that best meets their requirements, purchasers of PACS equipment need to be aware of the key characteristics and differing features of the various products. After the PACS has been installed, the user should perform technical and clinical acceptance testing to ensure that the system meets expectations.
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Affiliation(s)
- Ehsan Samei
- Department of Radiology, Duke University, DUMC Box 3302, Durham, NC 27710, USA.
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Averbukh AN, Channin DS, Flynn MJ. Assessment of a novel, high-resolution, color, AMLCD for diagnostic medical image display: luminance performance and DICOM calibration. J Digit Imaging 2003; 16:270-9. [PMID: 14669065 PMCID: PMC3045256 DOI: 10.1007/s10278-003-1718-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
This article documents the results of the first in a series of experiments designed to evaluate the suitability of a novel, high resolution, color, digital, liquid crystal display (LCD) panel for diagnostic quality, gray scale image display. The goal of this experiment was to measure the performance of the display, especially with respect to luminance. The panel evaluated was the IBM T221 22.2" backlit active matrix liquid crystal display (AMLCD) with native resolution of 3840 x 2400 pixels. Taking advantage of the color capabilities of the workstation, we were able to create a 256-entry grayscale calibration look-up table derived from a palette of 1786 nearly gray luminance values. We also constructed a 256-entry grayscale calibration look-up table derived from a palette of 256 true gray values for which the red, green, and blue values were equal. These calibrations will now be used in our evaluation of human contrast-detail perception on this LCD panel.
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Affiliation(s)
- Alice N Averbukh
- Northwestern University Medical School, 448 E. Ontario, Suite 300, Chicago, IL 60611, USA.
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