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Arias-Valcayo F, Galve P, Herraiz JL, Vaquero JJ, Desco M, Udías JM. Reconstruction of multi-animal PET acquisitions with anisotropically variant PSF. Biomed Phys Eng Express 2023; 9:065018. [PMID: 37703847 DOI: 10.1088/2057-1976/acf936] [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: 04/19/2023] [Accepted: 09/13/2023] [Indexed: 09/15/2023]
Abstract
Among other factors such as random, attenuation and scatter corrections, uniform spatial resolution is key to performing accurate quantitative studies in Positron emission tomography (PET). Particularly in preclinical PET studies involving simultaneous acquisition of multiple animals, the degradation of image resolution due to the depth of interaction (DOI) effect far from the center of the Field of View (FOV) becomes a significant concern. In this work, we incorporated a spatially-variant resolution model into a real time iterative reconstruction code to obtain accurate images of multi-animal acquisition. We estimated the spatially variant point spread function (SV-PSF) across the FOV using measurements and Monte Carlo (MC) simulations. The SV-PSF obtained was implemented in a GPU-based Ordered subset expectation maximization (OSEM) reconstruction code, which includes scatter, attenuation and random corrections. The method was evaluated with acquisitions from two preclinical PET/CT scanners of the SEDECAL Argus family: a Derenzo phantom placed 2 cm off center in the 4R-SuperArgus, and a multi-animal study with 4 mice in the 6R-SuperArgus. The SV-PSF reconstructions showed uniform spatial resolution without significant increase in reconstruction time, with superior image quality compared to the uniform PSF model.
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Affiliation(s)
- F Arias-Valcayo
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - P Galve
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
- Instituto de Investigación Del Hospital Clínico San Carlos (IdISSC), Ciudad Universitaria, Madrid, Spain
- Universite Paris Cite, PARCC, INSERM 56, rue Leblanc Paris, Île-de-France, France
| | - Joaquín L Herraiz
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
- Instituto de Investigación Del Hospital Clínico San Carlos (IdISSC), Ciudad Universitaria, Madrid, Spain
| | - J J Vaquero
- Departmento de Bioingeniería, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Maranón, Madrid, Spain
| | - M Desco
- Departmento de Bioingeniería, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Maranón, Madrid, Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- CIBER de Salud Mental, Instituto de Salud Carlos III, Madrid, Spain
| | - J M Udías
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
- Instituto de Investigación Del Hospital Clínico San Carlos (IdISSC), Ciudad Universitaria, Madrid, Spain
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2
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Delgado-Rodriguez P, Brooks CJ, Vaquero JJ, Muñoz-Barrutia A. Innovations in ex vivo Light Sheet Fluorescence Microscopy. Prog Biophys Mol Biol 2022; 168:37-51. [PMID: 34293338 DOI: 10.1016/j.pbiomolbio.2021.07.002] [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] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Light Sheet Fluorescence Microscopy (LSFM) has revolutionized how optical imaging of biological specimens can be performed as this technique allows to produce 3D fluorescence images of entire samples with a high spatiotemporal resolution. In this manuscript, we aim to provide readers with an overview of the field of LSFM on ex vivo samples. Recent advances in LSFM architectures have made the technique widely accessible and have improved its acquisition speed and resolution, among other features. These developments are strongly supported by quantitative analysis of the huge image volumes produced thanks to the boost in computational capacities, the advent of Deep Learning techniques, and by the combination of LSFM with other imaging modalities. Namely, LSFM allows for the characterization of biological structures, disease manifestations and drug effectivity studies. This information can ultimately serve to develop novel diagnostic procedures, treatments and even to model the organs physiology in healthy and pathological conditions.
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Affiliation(s)
- Pablo Delgado-Rodriguez
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
| | - Claire Jordan Brooks
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Arrate Muñoz-Barrutia
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
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3
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López-Montes A, Galve P, Udias JM, Cal-González J, Vaquero JJ, Desco M, Herraiz JL. Real-Time 3D PET Image with Pseudoinverse Reconstruction. Applied Sciences 2020. [DOI: https://doi.org/10.3390/app10082829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Real-time positron emission tomography (PET) may provide information from first-shot images, enable PET-guided biopsies, and allow awake animal studies. Fully-3D iterative reconstructions yield the best images in PET, but they are too slow for real-time imaging. Analytical methods such as Fourier back projection (FBP) are very fast, but yield images of poor quality with artifacts due to noise or data incompleteness. In this work, an image reconstruction based on the pseudoinverse of the system response matrix (SRM) is presented. w. To implement the pseudoinverse method, the reconstruction problem is separated into two stages. First, the axial part of the SRM is pseudo-inverted (PINV) to rebin the 3D data into 2D datasets. Then, the resulting 2D slices can be reconstructed with analytical methods or by applying the pseudoinverse algorithm again. The proposed two-step PINV reconstruction yielded good-quality images at a rate of several frames per second, compatible with real time applications. Furthermore, extremely fast direct PINV reconstruction of projections of the 3D image collapsed along specific directions can be implemented.
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Ortega-Gil A, Muñoz-Barrutia A, Roca JJ, Guijarro-López L, Vaquero JJ. A radiological score for the assessment of tuberculosis progression: Validation in mouse models. Tuberculosis (Edinb) 2020; 121:101918. [PMID: 32279874 DOI: 10.1016/j.tube.2020.101918] [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] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/05/2020] [Accepted: 02/29/2020] [Indexed: 11/30/2022]
Abstract
The sensitivity of in vivo low-dose high-resolution micro-computed tomography imaging enables monitoring the lung damage caused by tuberculosis. Here, we propose a radiological score integrated in the experimental workflow that enables longitudinal monitoring for prospective efficacy studies in drug development programs. The score is based on an automatic measurement of total unaffected lung volume in vivo normalized for inter-subject comparison. It was validated on well-characterized progression of chronic tuberculosis in Erdman and H37Rv strains in C3HeB/FeJ-based models. We demonstrated that a decrease in the score value indicates increasing adverse effects and vice versa. The colony-forming units count confirmed the variability in the host response suggested by the score values. The correlation between changes in the mice's weight and the score is consistent with disease progression. The classification of disease extent by k-means clustering of the score values provided the definition of the lung damage severity according to the bacillus strain. The proposed score will reduce sources of bias and improve the statistical robustness of studies by the attrition of non-infected subjects or subjects with a weak immune response. Readily available quantifications allow for a fast assessment of the therapeutic potential in drug-resistant tuberculosis strains.
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Affiliation(s)
- Ana Ortega-Gil
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain; Diseases of the Developing World, Infectious Diseases-Centre for Excellence in Drug Discovery (ID CEDD), GlaxoSmithKline, Madrid, Spain
| | - Arrate Muñoz-Barrutia
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.
| | - Jose Juan Roca
- Diseases of the Developing World, Infectious Diseases-Centre for Excellence in Drug Discovery (ID CEDD), GlaxoSmithKline, Madrid, Spain
| | - Laura Guijarro-López
- Diseases of the Developing World, Infectious Diseases-Centre for Excellence in Drug Discovery (ID CEDD), GlaxoSmithKline, Madrid, Spain
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
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Gordaliza PM, Muñoz-Barrutia A, Via LE, Sharpe S, Desco M, Vaquero JJ. Computed Tomography-Based Biomarker for Longitudinal Assessment of Disease Burden in Pulmonary Tuberculosis. Mol Imaging Biol 2019; 21:19-24. [PMID: 29845428 DOI: 10.1007/s11307-018-1215-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE Computed tomography (CT) images enable capturing specific manifestations of tuberculosis (TB) that are undetectable using common diagnostic tests, which suffer from limited specificity. In this study, we aimed to automatically quantify the burden of Mycobacterium tuberculosis (Mtb) using biomarkers extracted from x-ray CT images. PROCEDURES Nine macaques were aerosol-infected with Mtb and treated with various antibiotic cocktails. Chest CT scans were acquired in all animals at specific times independently of disease progression. First, a fully automatic segmentation of the healthy lungs from the acquired chest CT volumes was performed and air-like structures were extracted. Next, unsegmented pulmonary regions corresponding to damaged parenchymal tissue and TB lesions were included. CT biomarkers were extracted by classification of the probability distribution of the intensity of the segmented images into three tissue types: (1) Healthy tissue, parenchyma free from infection; (2) soft diseased tissue, and (3) hard diseased tissue. The probability distribution of tissue intensities was assumed to follow a Gaussian mixture model. The thresholds identifying each region were automatically computed using an expectation-maximization algorithm. RESULTS The estimated longitudinal course of TB infection shows that subjects that have followed the same antibiotic treatment present a similar response (relative change in the diseased volume) with respect to baseline. More interestingly, the correlation between the diseased volume (soft tissue + hard tissue), which was manually delineated by an expert, and the automatically extracted volume with the proposed method was very strong (R2 ≈ 0.8). CONCLUSIONS We present a methodology that is suitable for automatic extraction of a radiological biomarker from CT images for TB disease burden. The method could be used to describe the longitudinal evolution of Mtb infection in a clinical trial devoted to the design of new drugs.
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Affiliation(s)
- P M Gordaliza
- Dpto. Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - A Muñoz-Barrutia
- Dpto. Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, Spain. .,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
| | - L E Via
- Tuberculosis Research Section, LCIM, and Tuberculosis Imaging Program, DIR, NIAID, NIH, Bethesda, MD, USA
| | - S Sharpe
- National Infections Service, Public Health England, Porton Down, England
| | - M Desco
- Dpto. Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.,Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain.,Centro de Investigación Biomédica en Red de Salud Mental, Madrid, Spain
| | - J J Vaquero
- Dpto. Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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Cuarental L, Sucunza-Sáenz D, Valiño-Rivas L, Fernandez-Fernandez B, Sanz AB, Ortiz A, Vaquero JJ, Sanchez-Niño MD. MAP3K kinases and kidney injury. Nefrologia 2019; 39:568-580. [PMID: 31196660 DOI: 10.1016/j.nefro.2019.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022] Open
Abstract
Mitogen-activated protein kinases (MAP kinases) are functionally connected kinases that regulate key cellular process involved in kidney disease such as all survival, death, differentiation and proliferation. The typical MAP kinase module is composed by a cascade of three kinases: a MAP kinase kinase kinase (MAP3K) that phosphorylates and activates a MAP kinase kinase (MAP2K) which phosphorylates a MAP kinase (MAPK). While the role of MAPKs such as ERK, p38 and JNK has been well characterized in experimental kidney injury, much less is known about the apical kinases in the cascade, the MAP3Ks. There are 24 characterized MAP3K (MAP3K1 to MAP3K21 plus RAF1, BRAF and ARAF). We now review current knowledge on the involvement of MAP3K in non-malignant kidney disease and the therapeutic tools available. There is in vivo interventional evidence clearly supporting a role for MAP3K5 (ASK1) and MAP3K14 (NIK) in the pathogenesis of experimental kidney disease. Indeed, the ASK1 inhibitor Selonsertib has undergone clinical trials for diabetic kidney disease. Additionally, although MAP3K7 (MEKK7, TAK1) is required for kidney development, acutely targeting MAP3K7 protected from acute and chronic kidney injury; and targeting MAP3K8 (TPL2/Cot) protected from acute kidney injury. By contrast MAP3K15 (ASK3) may protect from hypertension and BRAF inhibitors in clinical use may induced acute kidney injury and nephrotic syndrome. Given their role as upstream regulators of intracellular signaling, MAP3K are potential therapeutic targets in kidney injury, as demonstrated for some of them. However, the role of most MAP3K in kidney disease remains unexplored.
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Affiliation(s)
| | - David Sucunza-Sáenz
- REDINREN, Spain; Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria, (IRYCIS), Madrid, Spain
| | | | | | - Ana Belen Sanz
- IIS-Fundacion Jimenez Diaz-UAM, Madrid, Spain; REDINREN, Spain
| | - Alberto Ortiz
- IIS-Fundacion Jimenez Diaz-UAM, Madrid, Spain; REDINREN, Spain
| | - Juan José Vaquero
- REDINREN, Spain; Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria, (IRYCIS), Madrid, Spain
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7
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Valiño-Rivas L, Vaquero JJ, Sucunza D, Gutierrez S, Sanz AB, Fresno M, Ortiz A, Sanchez-Niño MD. NIK as a Druggable Mediator of Tissue Injury. Trends Mol Med 2019; 25:341-360. [PMID: 30926358 DOI: 10.1016/j.molmed.2019.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/07/2019] [Accepted: 02/13/2019] [Indexed: 12/15/2022]
Abstract
NF-κB-inducing kinase (NIK, MAP3K14) is best known as the apical kinase that triggers non-canonical NF-κB activation and by its role in the immune system. Recent data indicate a role for NIK expressed by non-lymphoid cells in cancer, kidney disease, liver injury, glucose homeostasis, osteosarcopenia, vascular calcification, hematopoiesis, and endothelial function. The spectrum of NIK-associated disease now ranges from immunodeficiency (when NIK is defective) to autoimmunity, cancer, sterile inflammation, fibrosis, and metabolic disease when NIK is overactive. The development of novel small-molecule NIK inhibitors has paved the way to test NIK targeting to treat disease in vivo, and may eventually lead to NIK targeting in the clinic. In addition, NIK activators are being explored for specific conditions such as myeloid leukemia.
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Affiliation(s)
- Lara Valiño-Rivas
- Department of Nephrology and Hypertension, Instituto de Investigación Sanitaria (IIS) Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma de Madrid (UAM), Red de Investigación Renal (REDINREN), and Fundación Renal Íñigo Álvarez de Toledo (FRIAT), Madrid, Spain
| | - Juan José Vaquero
- Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcala and REDINREN, Madrid, Spain
| | - David Sucunza
- Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcala and REDINREN, Madrid, Spain
| | - Sara Gutierrez
- Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcala and REDINREN, Madrid, Spain
| | - Ana B Sanz
- Department of Nephrology and Hypertension, Instituto de Investigación Sanitaria (IIS) Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma de Madrid (UAM), Red de Investigación Renal (REDINREN), and Fundación Renal Íñigo Álvarez de Toledo (FRIAT), Madrid, Spain
| | - Manuel Fresno
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas de la UAM, Madrid, Spain
| | - Alberto Ortiz
- Department of Nephrology and Hypertension, Instituto de Investigación Sanitaria (IIS) Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma de Madrid (UAM), Red de Investigación Renal (REDINREN), and Fundación Renal Íñigo Álvarez de Toledo (FRIAT), Madrid, Spain; These authors contributed equally.
| | - Maria Dolores Sanchez-Niño
- Department of Nephrology and Hypertension, Instituto de Investigación Sanitaria (IIS) Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma de Madrid (UAM), Red de Investigación Renal (REDINREN), and Fundación Renal Íñigo Álvarez de Toledo (FRIAT), Madrid, Spain; These authors contributed equally.
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Albert-Smet I, Marcos-Vidal A, Vaquero JJ, Desco M, Muñoz-Barrutia A, Ripoll J. Applications of Light-Sheet Microscopy in Microdevices. Front Neuroanat 2019; 13:1. [PMID: 30760983 PMCID: PMC6362405 DOI: 10.3389/fnana.2019.00001] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/09/2019] [Indexed: 11/23/2022] Open
Abstract
Light-sheet fluorescence microscopy (LSFM) has been present in cell biology laboratories for quite some time, mainly as custom-made systems, with imaging applications ranging from single cells (in the micrometer scale) to small organisms (in the millimeter scale). Such microscopes distinguish themselves for having very low phototoxicity levels and high spatial and temporal resolution, properties that make them ideal for a large range of applications. These include the study of cellular dynamics, in particular cellular motion which is essential to processes such as tumor metastasis and tissue development. Experimental setups make extensive use of microdevices (bioMEMS) that provide better control over the substrate environment than traditional cell culture experiments. For example, to mimic in vivo conditions, experiment biochemical dynamics, and trap, move or count cells. Microdevices provide a higher degree of empirical complexity but, so far, most have been designed to be imaged through wide-field or confocal microscopes. Nonetheless, the properties of LSFM render it ideal for 3D characterization of active cells. When working with microdevices, confocal microscopy is more widespread than LSFM even though it suffers from higher phototoxicity and slower acquisition speeds. It is sometimes possible to illuminate with a light-sheet microdevices designed for confocal microscopes. However, these bioMEMS must be redesigned to exploit the full potential of LSFM and image more frequently on a wider scale phenomena such as motion, traction, differentiation, and diffusion of molecules. The use of microdevices for LSFM has extended beyond cell tracking studies into experiments regarding cytometry, spheroid cultures and lab-on-a-chip automation. Due to light-sheet microscopy being in its early stages, a setup of these characteristics demands some degree of optical expertise; and designing three-dimensional microdevices requires facilities, ingenuity, and experience in microfabrication. In this paper, we explore different approaches where light-sheet microscopy can achieve single-cell and subcellular resolution within microdevices, and provide a few pointers on how these experiments may be improved.
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Affiliation(s)
- Ignacio Albert-Smet
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain
| | - Asier Marcos-Vidal
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain
| | - Juan José Vaquero
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Experimental Medicine and Surgery Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón, Madrid, Spain
| | - Manuel Desco
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Experimental Medicine and Surgery Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón, Madrid, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Arrate Muñoz-Barrutia
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Experimental Medicine and Surgery Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón, Madrid, Spain
| | - Jorge Ripoll
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain.,Experimental Medicine and Surgery Unit, Instituto de Investigación Sanitaria del Hospital Gregorio Marañón, Madrid, Spain
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Cal-Gonzalez J, Vaquero JJ, Herraiz JL, Pérez-Liva M, Soto-Montenegro ML, Peña-Zalbidea S, Desco M, Udías JM. Improving PET Quantification of Small Animal [ 68Ga]DOTA-Labeled PET/CT Studies by Using a CT-Based Positron Range Correction. Mol Imaging Biol 2018; 20:584-593. [PMID: 29352372 DOI: 10.1007/s11307-018-1161-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Image quality of positron emission tomography (PET) tracers that emits high-energy positrons, such as Ga-68, Rb-82, or I-124, is significantly affected by positron range (PR) effects. PR effects are especially important in small animal PET studies, since they can limit spatial resolution and quantitative accuracy of the images. Since generators accessibility has made Ga-68 tracers wide available, the aim of this study is to show how the quantitative results of [68Ga]DOTA-labeled PET/X-ray computed tomography (CT) imaging of neuroendocrine tumors in mice can be improved using positron range correction (PRC). PROCEDURES Eighteen scans in 12 mice were evaluated, with three different models of tumors: PC12, AR42J, and meningiomas. In addition, three different [68Ga]DOTA-labeled radiotracers were used to evaluate the PRC with different tracer distributions: [68Ga]DOTANOC, [68Ga]DOTATOC, and [68Ga]DOTATATE. Two PRC methods were evaluated: a tissue-dependent (TD-PRC) and a tissue-dependent spatially-variant correction (TDSV-PRC). Taking a region in the liver as reference, the tissue-to-liver ratio values for tumor tissue (TLRtumor), lung (TLRlung), and necrotic areas within the tumors (TLRnecrotic) and their respective relative variations (ΔTLR) were evaluated. RESULTS All TLR values in the PRC images were significantly different (p < 0.05) than the ones from non-PRC images. The relative differences of the tumor TLR values, respect to the case with no PRC, were ΔTLRtumor 87 ± 41 % (TD-PRC) and 85 ± 46 % (TDSV-PRC). TLRlung decreased when applying PRC, being this effect more remarkable for the TDSV-PRC method, with relative differences respect to no PRC: ΔTLRlung = - 45 ± 24 (TD-PRC), - 55 ± 18 (TDSV-PRC). TLRnecrotic values also decreased when using PRC, with more noticeable differences for TD-PRC: ΔTLRnecrotic = - 52 ± 6 (TD-PRC), - 48 ± 8 (TDSV-PRC). CONCLUSION The PRC methods proposed provide a significant quantitative improvement in [68Ga]DOTA-labeled PET/CT imaging of mice with neuroendocrine tumors, hence demonstrating that these techniques could also ameliorate the deleterious effect of the positron range in clinical PET imaging.
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Affiliation(s)
- Jacobo Cal-Gonzalez
- QIMP group, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Joaquín L Herraiz
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - Mailyn Pérez-Liva
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | | | - Santiago Peña-Zalbidea
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- IRAB-Institut de Radiofarmàcia Aplicada de Barcelona (PRBB), Barcelona, Spain
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- CIBERSAM, Madrid, Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - José Manuel Udías
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
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10
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Gordaliza PM, Muñoz-Barrutia A, Abella M, Desco M, Sharpe S, Vaquero JJ. Unsupervised CT Lung Image Segmentation of a Mycobacterium Tuberculosis Infection Model. Sci Rep 2018; 8:9802. [PMID: 29955159 PMCID: PMC6023884 DOI: 10.1038/s41598-018-28100-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 06/12/2018] [Indexed: 02/06/2023] Open
Abstract
Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis that produces pulmonary damage. Radiological imaging is the preferred technique for the assessment of TB longitudinal course. Computer-assisted identification of biomarkers eases the work of the radiologist by providing a quantitative assessment of disease. Lung segmentation is the step before biomarker extraction. In this study, we present an automatic procedure that enables robust segmentation of damaged lungs that have lesions attached to the parenchyma and are affected by respiratory movement artifacts in a Mycobacterium Tuberculosis infection model. Its main steps are the extraction of the healthy lung tissue and the airway tree followed by elimination of the fuzzy boundaries. Its performance was compared with respect to a segmentation obtained using: (1) a semi-automatic tool and (2) an approach based on fuzzy connectedness. A consensus segmentation resulting from the majority voting of three experts' annotations was considered our ground truth. The proposed approach improves the overlap indicators (Dice similarity coefficient, 94% ± 4%) and the surface similarity coefficients (Hausdorff distance, 8.64 mm ± 7.36 mm) in the majority of the most difficult-to-segment slices. Results indicate that the refined lung segmentations generated could facilitate the extraction of meaningful quantitative data on disease burden.
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Affiliation(s)
- Pedro M Gordaliza
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial, Leganés, ES28911, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, ES28007, Spain
| | - Arrate Muñoz-Barrutia
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial, Leganés, ES28911, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, ES28007, Spain
| | - Mónica Abella
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial, Leganés, ES28911, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, ES28007, Spain
- Centro de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Manuel Desco
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial, Leganés, ES28911, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, ES28007, Spain
- Centro de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, ES28029, Spain
| | - Sally Sharpe
- Public Health England, Microbiology Services Division, Porton Down, SP4 0JG, England
| | - Juan José Vaquero
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial, Leganés, ES28911, Spain.
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, ES28007, Spain.
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11
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Cal-Gonzalez J, Vaquero JJ, Herraiz JL, Pérez-Liva M, Soto-Montenegro ML, Peña-Zalbidea S, Desco M, Udías JM. Improving PET Quantification of Small Animal [68Ga]DOTA-Labeled PET/CT Studies by Using a CT-Based Positron Range Correction. Mol Imaging Biol 2018. [DOI: https://doi.org/10.1007/s11307-018-1161-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Gómez-Gaviro MV, Balaban E, Bocancea D, Lorrio MT, Pompeiano M, Desco M, Ripoll J, Vaquero JJ. Optimized CUBIC protocol for three-dimensional imaging of chicken embryos at single-cell resolution. Development 2017; 144:2092-2097. [PMID: 28432219 DOI: 10.1242/dev.145805] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [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: 01/25/2017] [Accepted: 04/07/2017] [Indexed: 01/17/2023]
Abstract
The CUBIC tissue-clearing protocol has been optimized to produce translucent immunostained whole chicken embryos and embryo brains. When combined with multispectral light-sheet microscopy, the validated protocol presented here provides a rapid, inexpensive and reliable method for acquiring accurate histological images that preserve three-dimensional structural relationships with single-cell resolution in whole early-stage chicken embryos and in the whole brains of late-stage embryos.
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Affiliation(s)
- María Victoria Gómez-Gaviro
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain .,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, 28007, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, 28029, Spain
| | - Evan Balaban
- Department of Psychology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Diana Bocancea
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain
| | - María Teresa Lorrio
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain
| | - Maria Pompeiano
- Department of Psychology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, 28007, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, 28029, Spain
| | - Jorge Ripoll
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, 28007, Spain
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Leganés, 28911, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, 28007, Spain
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Vaquero JJ, Kinahan P. Positron Emission Tomography: Current Challenges and Opportunities for Technological Advances in Clinical and Preclinical Imaging Systems. Annu Rev Biomed Eng 2016; 17:385-414. [PMID: 26643024 DOI: 10.1146/annurev-bioeng-071114-040723] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges.
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Affiliation(s)
- Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, 28911 Madrid, Spain, and Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain;
| | - Paul Kinahan
- Departments of Radiology, Bioengineering, and Physics, University of Washington, Seattle, Washington 98195;
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Nehrhoff I, Bocancea D, Vaquero J, Vaquero JJ, Ripoll J, Desco M, Gómez-Gaviro MV. 3D imaging in CUBIC-cleared mouse heart tissue: going deeper. Biomed Opt Express 2016; 7:3716-3720. [PMID: 27699132 PMCID: PMC5030044 DOI: 10.1364/boe.7.003716] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/12/2016] [Accepted: 08/23/2016] [Indexed: 06/06/2023]
Abstract
The ability to acquire high resolution 3D images of the heart enables to study heart diseases more in detail. In this work, the CUBIC (clear, unobstructed brain imaging cocktails and computational analysis) clearing protocol was optimized for thick mouse heart sections to enhance the penetration depth of the confocal microscope lasers into the tissue. In addition, the optimized CUBIC clearing of the heart enhances antibody penetration into the tissue by a factor of five. The present protocol enables deep 3D high-quality image acquisition in the heart allowing a much more accurate assessment of the cellular and structural changes that underlie heart diseases.
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Affiliation(s)
- Imke Nehrhoff
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- These authors contributed equally to this work
| | - Diana Bocancea
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
- These authors contributed equally to this work
| | - Javier Vaquero
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- CIBER de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, Spain
| | - Juan José Vaquero
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
| | - Jorge Ripoll
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
| | - Manuel Desco
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - María Victoria Gómez-Gaviro
- Instituto de Investigación Sanitaria Gregorio Marañón. (IiSGM), Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
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15
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Mateos-Pérez JM, Soto-Montenegro ML, Peña-Zalbidea S, Desco M, Vaquero JJ. Functional segmentation of dynamic PET studies: Open source implementation and validation of a leader-follower-based algorithm. Comput Biol Med 2016; 69:181-8. [PMID: 26773940 DOI: 10.1016/j.compbiomed.2015.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 11/26/2022]
Abstract
UNLABELLED We present a novel segmentation algorithm for dynamic PET studies that groups pixels according to the similarity of their time-activity curves. METHODS Sixteen mice bearing a human tumor cell line xenograft (CH-157MN) were imaged with three different (68)Ga-DOTA-peptides (DOTANOC, DOTATATE, DOTATOC) using a small animal PET-CT scanner. Regional activities (input function and tumor) were obtained after manual delineation of regions of interest over the image. The algorithm was implemented under the jClustering framework and used to extract the same regional activities as in the manual approach. The volume of distribution in the tumor was computed using the Logan linear method. A Kruskal-Wallis test was used to investigate significant differences between the manually and automatically obtained volumes of distribution. RESULTS The algorithm successfully segmented all the studies. No significant differences were found for the same tracer across different segmentation methods. Manual delineation revealed significant differences between DOTANOC and the other two tracers (DOTANOC - DOTATATE, p=0.020; DOTANOC - DOTATOC, p=0.033). Similar differences were found using the leader-follower algorithm. CONCLUSION An open implementation of a novel segmentation method for dynamic PET studies is presented and validated in rodent studies. It successfully replicated the manual results obtained in small-animal studies, thus making it a reliable substitute for this task and, potentially, for other dynamic segmentation procedures.
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Affiliation(s)
- José María Mateos-Pérez
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.
| | - María Luisa Soto-Montenegro
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Santiago Peña-Zalbidea
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
| | - Manuel Desco
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
| | - Juan José Vaquero
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
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Cal-González J, Moore SC, Park MA, Herraiz JL, Vaquero JJ, Desco M, Udias JM. Improved quantification for local regions of interest in preclinical PET imaging. Phys Med Biol 2015. [DOI: https://doi.org/10.1088/0031-9155/60/18/7127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Gordaliza PM, Mateos-Pérez JM, Montesinos P, Guzmán-de-Villoria JA, Desco M, Vaquero JJ. Development and validation of an open source quantification tool for DSC-MRI studies. Comput Biol Med 2015; 58:56-62. [PMID: 25618215 DOI: 10.1016/j.compbiomed.2015.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/19/2014] [Accepted: 01/01/2015] [Indexed: 11/28/2022]
Abstract
MOTIVATION This work presents the development of an open source tool for the quantification of dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion studies. The development of this tool is motivated by the lack of open source tools implemented on open platforms to allow external developers to implement their own quantification methods easily and without the need of paying for a development license. MATERIALS AND METHODS This quantification tool was developed as a plugin for the ImageJ image analysis platform using the Java programming language. A modular approach was used in the implementation of the components, in such a way that the addition of new methods can be done without breaking any of the existing functionalities. For the validation process, images from seven patients with brain tumors were acquired and quantified with the presented tool and with a widely used clinical software package. The resulting perfusion parameters were then compared. RESULTS Perfusion parameters and the corresponding parametric images were obtained. When no gamma-fitting is used, an excellent agreement with the tool used as a gold-standard was obtained (R(2)>0.8 and values are within 95% CI limits in Bland-Altman plots). CONCLUSION An open source tool that performs quantification of perfusion studies using magnetic resonance imaging has been developed and validated using a clinical software package. It works as an ImageJ plugin and the source code has been published with an open source license.
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Affiliation(s)
- P M Gordaliza
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain.
| | - J M Mateos-Pérez
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - P Montesinos
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
| | - J A Guzmán-de-Villoria
- Servicio de Radiodiagnóstico, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - M Desco
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - J J Vaquero
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain.
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Abstract
Positron emission tomography (PET) is an important technique in cardiovascular research. Vascular inflammation detected by fluorodeoxyglucose (FDG)-PET has been shown to predict cardiovascular (CV) events independent of traditional risk factors and is also highly associated with overall burden of atherosclerosis. The use of PET imaging in mouse models of atherosclerosis is challenged by the reduced size of the scanned organs. However, the last generation of dedicated PET scanners has an improved spatial resolution (<1 mm) and increased sensitivity allowing those studies to be performed. Here, we describe a procedure to perform FDG-PET experiments in atherosclerosis mouse models, the required equipment for animal handling and imaging, and the tools and procedures for image analysis and validation of the results.
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Affiliation(s)
- Jesús Mateo
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Izaskun Bilbao
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Universidad Complutense de Madrid and CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Juan José Vaquero
- Departamento de Bioingeniería & Ingeniería Aeroespacial, Universidad Carlos III Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Jesús Ruiz-Cabello
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Departamento de Bioingeniería & Ingeniería Aeroespacial, Universidad Carlos III Madrid, Madrid, Spain
| | - Samuel España
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain.
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Cussó L, Vaquero JJ, Bacharach S, Desco M. Comparison of methods to reduce myocardial 18F-FDG uptake in mice: calcium channel blockers versus high-fat diets. PLoS One 2014; 9:e107999. [PMID: 25238619 PMCID: PMC4169612 DOI: 10.1371/journal.pone.0107999] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 08/20/2014] [Indexed: 01/31/2023] Open
Abstract
Purpose Besides its application in oncology, 18F-FDG PET-CT imaging is also useful in the diagnosis of certain lung infections, inflammatory diseases, and atherosclerotic plaques. Myocardial uptake of 18F-FDG may hamper visualization of the lesions caused by these diseases. Two approaches have been proposed for reducing myocardial uptake in preclinical studies, namely, calcium channel blockers (verapamil) and high-fat diets such as commercial ketogenic diets and sunflower seed diets. The objective of this study was to compare the efficacy of these approaches in reducing myocardial uptake of 18F-FDG in mice. Methods We performed two experiments. In experiment A, each animal underwent four 18F-FDG PET/CT scans in the following order: baseline, after administration of verapamil, after two days on ketogenic diet and after two days on sunflower seeds. PET scans were performed 60 minutes after injection of 18.5 MBq of 18F-FDG. In experiment B, the best protocol of the three (ketogenic diet) was evaluated in a lung inflammation model to assess the efficacy of reducing myocardial uptake of 18F-FDG. Results Compared with baseline (SUV 2.03±1.21); the greatest reduction in uptake of 18F-FDG was with ketogenic diet (SUV 0.79±0.16; p = 0.008), followed by sunflower seeds (SUV 0.91±0.13; p = 0.015); the reduction in myocardial uptake produced by verapamil was not statistically significant (SUV 1.78±0.79; p = NS). In experiment B, complete suppression of myocardial uptake noticeably improved the visualization of inflamed areas near the heart, while in the case of null or partial myocardial suppression, it was much harder to distinguish lung inflammation from myocardial spillover. Conclusion A high-fat diet appeared to be the most effective method for decreasing myocardial uptake of 18F-FDG in healthy mice, outperforming verapamil. Our findings also demonstrate that ketogenic diet actually improves visualization of inflammatory lesions near the heart.
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Affiliation(s)
- Lorena Cussó
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- * E-mail:
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Stephen Bacharach
- Department of Radiology, Nuclear Medicine Section, University of California San Francisco, San Francisco, California, United States of America
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
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Abstract
This work presents an approach to extend the dynamic range of x-ray flat panel detectors by combining two acquisitions of the same sample taken with two different x-ray photon flux levels and the same beam spectral configuration. In order to combine both datasets, the response of detector pixels was modelled in terms of mean and variance using a linear model. The model was extended to take into account the effect of pixel saturation. We estimated a joint probability density function (j-pdf) of the pixel values by assuming that each dataset follows an independent Gaussian distribution. This j-pdf was used for estimating the final pixel value of the high-dynamic-range dataset using a maximum likelihood method. The suitability of the pixel model for the representation of the detector signal was assessed using experimental data from a small-animal cone-beam micro-CT scanner equipped with a flat panel detector. The potential extension in dynamic range offered by our method was investigated for generic flat panel detectors using analytical expressions and simulations. The performance of the proposed dual-exposure approach in realistic imaging environments was compared with that of a regular single-exposure technique using experimental data from two different phantoms. Image quality was assessed in terms of signal-to-noise ratio, contrast, and analysis of profiles drawn on the images. The dynamic range, measured as the ratio between the exposure for saturation and the exposure equivalent to instrumentation noise, was increased from 76.9 to 166.7 when using our method. Dual-exposure results showed higher contrast-to-noise ratio and contrast resolution than the single-exposure acquisitions for the same x-ray dose. In addition, image artifacts were reduced in the combined dataset. This technique to extend the dynamic range of the detector without increasing the dose is particularly suited to image samples that contain both low and high attenuation regions.
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Affiliation(s)
- A Sisniega
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
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Montesinos P, Abascal JFP, Cussó L, Vaquero JJ, Desco M. Application of the compressed sensing technique to self-gated cardiac cine sequences in small animals. Magn Reson Med 2013; 72:369-80. [DOI: 10.1002/mrm.24936] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 07/17/2013] [Accepted: 08/04/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Paula Montesinos
- Departamento de Bioingeniería e Ingeniería Aeroespacial; Universidad Carlos III de Madrid; Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM); Madrid Spain
| | - Juan Felipe P.J. Abascal
- Departamento de Bioingeniería e Ingeniería Aeroespacial; Universidad Carlos III de Madrid; Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM); Madrid Spain
| | - Lorena Cussó
- Departamento de Bioingeniería e Ingeniería Aeroespacial; Universidad Carlos III de Madrid; Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM); Madrid Spain
- Centro de Investigación Biomédica En Red de Salud Mental; CIBERSAM; Madrid Spain
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial; Universidad Carlos III de Madrid; Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM); Madrid Spain
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial; Universidad Carlos III de Madrid; Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM); Madrid Spain
- Centro de Investigación Biomédica En Red de Salud Mental; CIBERSAM; Madrid Spain
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Abstract
Technical advances towards high resolution PET imaging try to overcome the inherent physical limitations to spatial resolution. Positrons travel in tissue until they annihilate into the two gamma photons detected. This range is the main detector-independent contribution to PET imaging blurring. To a large extent, it can be remedied during image reconstruction if accurate estimates of positron range are available. However, the existing estimates differ, and the comparison with the scarce experimental data available is not conclusive. In this work we present positron annihilation distributions obtained from Monte Carlo simulations with the PeneloPET simulation toolkit, for several common PET isotopes ((18)F, (11)C, (13)N, (15)O, (68)Ga and (82)Rb) in different biological media (cortical bone, soft bone, skin, muscle striated, brain, water, adipose tissue and lung). We compare PeneloPET simulations against experimental data and other simulation results available in the literature. To this end the different positron range representations employed in the literature are related to each other by means of a new parameterization for positron range profiles. Our results are generally consistent with experiments and with most simulations previously reported with differences of less than 20% in the mean and maximum range values. From these results, we conclude that better experimental measurements are needed, especially to disentangle the effect of positronium formation in positron range. Finally, with the aid of PeneloPET, we confirm that scaling approaches can be used to obtain universal, material and isotope independent, positron range profiles, which would considerably simplify range correction.
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Affiliation(s)
- J Cal-González
- Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
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Cal-González J, Herraiz JL, España S, Corzo PMG, Vaquero JJ, Desco M, Udias JM. Positron range estimations with PeneloPET. Phys Med Biol 2013. [DOI: https://doi.org/10.1088/0031-9155/58/15/5127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sisniega A, Zbijewski W, Badal A, Kyprianou IS, Stayman JW, Vaquero JJ, Siewerdsen JH. Monte Carlo study of the effects of system geometry and antiscatter grids on cone-beam CT scatter distributions. Med Phys 2013; 40:051915. [PMID: 23635285 PMCID: PMC3651212 DOI: 10.1118/1.4801895] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 03/08/2013] [Accepted: 03/24/2013] [Indexed: 01/23/2023] Open
Abstract
PURPOSE The proliferation of cone-beam CT (CBCT) has created interest in performance optimization, with x-ray scatter identified among the main limitations to image quality. CBCT often contends with elevated scatter, but the wide variety of imaging geometry in different CBCT configurations suggests that not all configurations are affected to the same extent. Graphics processing unit (GPU) accelerated Monte Carlo (MC) simulations are employed over a range of imaging geometries to elucidate the factors governing scatter characteristics, efficacy of antiscatter grids, guide system design, and augment development of scatter correction. METHODS A MC x-ray simulator implemented on GPU was accelerated by inclusion of variance reduction techniques (interaction splitting, forced scattering, and forced detection) and extended to include x-ray spectra and analytical models of antiscatter grids and flat-panel detectors. The simulator was applied to small animal (SA), musculoskeletal (MSK) extremity, otolaryngology (Head), breast, interventional C-arm, and on-board (kilovoltage) linear accelerator (Linac) imaging, with an axis-to-detector distance (ADD) of 5, 12, 22, 32, 60, and 50 cm, respectively. Each configuration was modeled with and without an antiscatter grid and with (i) an elliptical cylinder varying 70-280 mm in major axis; and (ii) digital murine and anthropomorphic models. The effects of scatter were evaluated in terms of the angular distribution of scatter incident upon the detector, scatter-to-primary ratio (SPR), artifact magnitude, contrast, contrast-to-noise ratio (CNR), and visual assessment. RESULTS Variance reduction yielded improvements in MC simulation efficiency ranging from ∼17-fold (for SA CBCT) to ∼35-fold (for Head and C-arm), with the most significant acceleration due to interaction splitting (∼6 to ∼10-fold increase in efficiency). The benefit of a more extended geometry was evident by virtue of a larger air gap-e.g., for a 16 cm diameter object, the SPR reduced from 1.5 for ADD = 12 cm (MSK geometry) to 1.1 for ADD = 22 cm (Head) and to 0.5 for ADD = 60 cm (C-arm). Grid efficiency was higher for configurations with shorter air gap due to a broader angular distribution of scattered photons-e.g., scatter rejection factor ∼0.8 for MSK geometry versus ∼0.65 for C-arm. Grids reduced cupping for all configurations but had limited improvement on scatter-induced streaks and resulted in a loss of CNR for the SA, Breast, and C-arm. Relative contribution of forward-directed scatter increased with a grid (e.g., Rayleigh scatter fraction increasing from ∼0.15 without a grid to ∼0.25 with a grid for the MSK configuration), resulting in scatter distributions with greater spatial variation (the form of which depended on grid orientation). CONCLUSIONS A fast MC simulator combining GPU acceleration with variance reduction provided a systematic examination of a range of CBCT configurations in relation to scatter, highlighting the magnitude and spatial uniformity of individual scatter components, illustrating tradeoffs in CNR and artifacts and identifying the system geometries for which grids are more beneficial (e.g., MSK) from those in which an extended geometry is the better defense (e.g., C-arm head imaging). Compact geometries with an antiscatter grid challenge assumptions of slowly varying scatter distributions due to increased contribution of Rayleigh scatter.
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Affiliation(s)
- A Sisniega
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, USA
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Vicente E, Herraiz JL, España S, Herranz E, Desco M, Vaquero JJ, Udías JM. Improved dead-time correction for PET scanners: application to small-animal PET. Phys Med Biol 2013; 58:2059-72. [PMID: 23459028 DOI: 10.1088/0031-9155/58/7/2059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 02/07/2023]
Abstract
Pile-up and dead-time are two main causes of nonlinearity in the response of a PET scanner as a function of activity in the field of view (FOV). For a given scanner and acquisition system, pile-up effects depend on the material and size of the object being imaged and on the distribution of activity inside and outside the FOV, because these factors change the singles-to-coincidences ratio (SCR). Thus, it is difficult to devise an accurate correction that would be valid for any acquisition. In this work, we demonstrate a linear relationship between SCR and effective dead-time, which measures the effects of both dead-time (losses) and pile-up (gains and losses). This relationship allows us to propose a simple method to accurately estimate dead-time and pile-up corrections using only two calibration acquisitions with, respectively, a high and low SCR. The method has been tested with simulations and experimental data for two different scanner geometries: a scanner with large area detectors and no pile-up rejection, and a scanner composed of two full rings of smaller detectors. Our results show that the SCR correction method is accurate within 7%, even for high activities in the FOV, and avoids the bias of the standard single-parameter method.
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Affiliation(s)
- E Vicente
- Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
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Vicente E, Herraiz JL, España S, Herranz E, Desco M, Vaquero JJ, Udías JM. Improved dead-time correction for PET scanners: application to small-animal PET. Phys Med Biol 2013. [DOI: https://doi.org/10.1088/0031-9155/58/7/2059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abella M, Vicente E, Rodríguez-Ruano A, España S, Lage E, Desco M, Udias JM, Vaquero JJ. Misalignments calibration in small-animal PET scanners based on rotating planar detectors and parallel-beam geometry. Phys Med Biol 2012; 57:7493-518. [DOI: 10.1088/0031-9155/57/22/7493] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abella M, Vaquero JJ, Sisniega A, Pascau J, Udías A, García V, Vidal I, Desco M. Software architecture for multi-bed FDK-based reconstruction in X-ray CT scanners. Comput Methods Programs Biomed 2012; 107:218-232. [PMID: 21908068 DOI: 10.1016/j.cmpb.2011.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 05/13/2011] [Accepted: 06/23/2011] [Indexed: 05/31/2023]
Abstract
Most small-animal X-ray computed tomography (CT) scanners are based on cone-beam geometry with a flat-panel detector orbiting in a circular trajectory. Image reconstruction in these systems is usually performed by approximate methods based on the algorithm proposed by Feldkamp et al. (FDK). Besides the implementation of the reconstruction algorithm itself, in order to design a real system it is necessary to take into account numerous issues so as to obtain the best quality images from the acquired data. This work presents a comprehensive, novel software architecture for small-animal CT scanners based on cone-beam geometry with circular scanning trajectory. The proposed architecture covers all the steps from the system calibration to the volume reconstruction and conversion into Hounsfield units. It includes an efficient implementation of an FDK-based reconstruction algorithm that takes advantage of system symmetries and allows for parallel reconstruction using a multiprocessor computer. Strategies for calibration and artifact correction are discussed to justify the strategies adopted. New procedures for multi-bed misalignment, beam-hardening, and Housfield units calibration are proposed. Experiments with phantoms and real data showed the suitability of the proposed software architecture for an X-ray small animal CT based on cone-beam geometry.
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Affiliation(s)
- M Abella
- Unidad de Medicina Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
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Suárez RM, Matía MP, Novella JL, Molina A, Cosme A, Vaquero JJ, Alvarez-Builla J. Synthesis of 9,9'-[1,2-ethanediylbis(oxymethylene)]bis-2-amino-1,9-dihydro-6H-purin-6-one, an impurity of acyclovir. Molecules 2012; 17:8735-41. [PMID: 22832875 PMCID: PMC6268874 DOI: 10.3390/molecules17088735] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 11/20/2022] Open
Abstract
The synthesis of 9,9'-[1,2-ethanediylbis(oxymethylene)]bis-2-amino-1,9-dihydro-6H-purin-6-one, a minor impurity of acyclovir, is described. Starting with commercial N-(9-acetyl-6-oxo-1H-purin-2-yl)acetamide, the process uses an acid catalysed phase transfer catalysis (PTC) process to produce the selective alkylation at the 9 position of the guanine ring.
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Affiliation(s)
- Rosa M. Suárez
- Fine Chemicals Pilot Plant Facility, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - Maria Paz Matía
- Fine Chemicals Pilot Plant Facility, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - José Luis Novella
- Fine Chemicals Pilot Plant Facility, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - Andres Molina
- Department of Research and Development, Química Sintética S. A., c./Dulcinea s/n, 28805 Alcala de Henares, Madrid, Spain
| | - Antonio Cosme
- Department of Research and Development, Química Sintética S. A., c./Dulcinea s/n, 28805 Alcala de Henares, Madrid, Spain
| | - Juan José Vaquero
- Department of Organic Chemistry, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
| | - Julio Alvarez-Builla
- Department of Organic Chemistry, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
- Author to whom correspondence should be addressed; ; Tel.: +34-91-885-4606; Fax: +34-91-885-4686
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Goertzen AL, Bao Q, Bergeron M, Blankemeyer E, Blinder S, Cañadas M, Chatziioannou AF, Dinelle K, Elhami E, Jans HS, Lage E, Lecomte R, Sossi V, Surti S, Tai YC, Vaquero JJ, Vicente E, Williams DA, Laforest R. NEMA NU 4-2008 comparison of preclinical PET imaging systems. J Nucl Med 2012; 53:1300-9. [PMID: 22699999 DOI: 10.2967/jnumed.111.099382] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no standard testing procedures for preclinical PET systems, and manufacturers could not provide clear specifications similar to those available for clinical systems under NEMA NU 2-1994 and 2-2001. Consequently, performance evaluation papers used methods that were modified ad hoc from the clinical PET NEMA standard, thus making comparisons between systems difficult. METHODS We acquired NEMA NU 4-2008 performance data for a collection of commercial animal PET systems manufactured since 2000: microPET P4, microPET R4, microPET Focus 120, microPET Focus 220, Inveon, ClearPET, Mosaic HP, Argus (formerly eXplore Vista), VrPET, LabPET 8, and LabPET 12. The data included spatial resolution, counting-rate performance, scatter fraction, sensitivity, and image quality and were acquired using settings for routine PET. RESULTS The data showed a steady improvement in system performance for newer systems as compared with first-generation systems, with notable improvements in spatial resolution and sensitivity. CONCLUSION Variation in system design makes direct comparisons between systems from different vendors difficult. When considering the results from NEMA testing, one must also consider the suitability of the PET system for the specific imaging task at hand.
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Pascau J, Vaquero JJ, Chamorro-Servent J, Rodríguez-Ruano A, Desco M. A method for small-animal PET/CT alignment calibration. Phys Med Biol 2012; 57:N199-207. [DOI: 10.1088/0031-9155/57/12/n199] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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32
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Higuera-Matas A, Soto-Montenegro ML, Montoya GL, García-Vázquez V, Pascau J, Miguéns M, Del Olmo N, Vaquero JJ, García-Lecumberri C, Desco M, Ambrosio E. Chronic cannabinoid administration to periadolescent rats modulates the metabolic response to acute cocaine in the adult brain. Mol Imaging Biol 2011; 13:411-415. [PMID: 20680479 DOI: 10.1007/s11307-010-0388-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE To analyze brain metabolic response to acute cocaine in male and female Wistar rats with or without a history of cannabinoid exposure during periadolescence. PROCEDURES The synthetic cannabinoid agonist CP 55,940 (CP) or its vehicle (VH), were administered to male and female rats during periadolescence. When these animals reached adulthood, saline and cocaine-induced changes in 2-deoxy-2-[¹⁸F]fluoro-D-: glucose (FDG) uptake were studied by positron emission tomography. RESULTS The baseline (post-saline) metabolism in the septal nuclei was higher in CP-females than in VH-females, although septal metabolism was lower in CP-females after cocaine, reaching similar values to those of VH-females at baseline. Cocaine did not affect metabolism in VH-females. Periadolescent cannabinoid treatment did not influence baseline metabolism in males although cocaine reduced the FDG uptake in the dorsal striatum of males that received the VH but not CP. CONCLUSIONS These results suggest that cannabinoids during periadolescence modify baseline and cocaine-evoked brain metabolism in a sex-dependent manner. In the case of CP-females, the involvement of septal metabolic alterations in their susceptibility to the rewarding effects of cocaine should be further investigated.
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Affiliation(s)
- Alejandro Higuera-Matas
- Psychobiology Department, School of Psychology, UNED, C/Juan del Rosal nº10, 28040, Madrid, Spain. .,Department of Pharmacology, School of Medicine, Universidad Complutense, Madrid, Spain.
| | - Maria Luisa Soto-Montenegro
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,CIBERSAM, Madrid, Spain
| | - Gonzalo L Montoya
- Psychobiology Department, School of Psychology, UNED, C/Juan del Rosal nº10, 28040, Madrid, Spain.,Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | | | - Javier Pascau
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Miguel Miguéns
- Psychobiology Department, School of Psychology, UNED, C/Juan del Rosal nº10, 28040, Madrid, Spain
| | - Nuria Del Olmo
- Department of Pharmaceutical and Food Sciences, School of Pharmacy, CEU University, Madrid, Spain
| | - Juan José Vaquero
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Carmen García-Lecumberri
- Psychobiology Department, School of Psychology, UNED, C/Juan del Rosal nº10, 28040, Madrid, Spain
| | - Manuel Desco
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,CIBERSAM, Madrid, Spain
| | - Emilio Ambrosio
- Psychobiology Department, School of Psychology, UNED, C/Juan del Rosal nº10, 28040, Madrid, Spain
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Chamorro-Servent J, Aguirre J, Ripoll J, Vaquero JJ, Desco M. Feasibility of U-curve method to select the regularization parameter for fluorescence diffuse optical tomography in phantom and small animal studies. Opt Express 2011; 19:11490-506. [PMID: 21716381 DOI: 10.1364/oe.19.011490] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
When dealing with ill-posed problems such as fluorescence diffuse optical tomography (fDOT) the choice of the regularization parameter is extremely important for computing a reliable reconstruction. Several automatic methods for the selection of the regularization parameter have been introduced over the years and their performance depends on the particular inverse problem. Herein a U-curve-based algorithm for the selection of regularization parameter has been applied for the first time to fDOT. To increase the computational efficiency for large systems an interval of the regularization parameter is desirable. The U-curve provided a suitable selection of the regularization parameter in terms of Picard's condition, image resolution and image noise. Results are shown both on phantom and mouse data.
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Affiliation(s)
- Judit Chamorro-Servent
- Departamento de Bioingeniería e Ingeniería Aerospacial, Universidad Carlos III de Madrid, Leganés, Spain
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Lage E, Tapias G, Villena J, Desco M, Vaquero JJ. Data acquisition electronics for gamma ray emission tomography using width-modulated leading-edge discriminators. Phys Med Biol 2010; 55:4291-308. [PMID: 20647602 DOI: 10.1088/0031-9155/55/15/007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present a new high-performance and low-cost approach for implementing radiation detection acquisition systems. The basic elements used are charge-integrating ADCs and a set of components encapsulated in an HDL (hardware definition language) library which makes it possible to implement several acquisition tasks such as time pickoff and coincidence detection using a new and simple trigger technique that we name WMLET (width-modulated leading-edge timing). As proof of concept, a 32-channel hybrid PET/SPECT acquisition system based on these elements was developed and tested. This demonstrator consists of a master module responsible for the generation and distribution of trigger signals, 2 x 16-channel ADC cards (12-bit resolution) for data digitization and a 32-bit digital I/O PCI card for handling data transmission to a personal computer. System characteristics such as linearity, maximum transmission rates or timing resolution in coincidence mode were evaluated with test and real detector signals. Imaging capabilities of the prototype were also evaluated using different detector configurations. The performance tests showed that this implementation is able to handle data rates in excess of 600k events s(-1) when acquiring simultaneously 32 channels (96-byte events). ADC channel linearity is >98.5% in energy quantification. Time resolution in PET mode for the tested configurations ranges from 3.64 ns FWHM to 7.88 ns FWHM when signals from LYSO-based detectors are used. The measured energy resolution matched the expected values for the detectors evaluated and single elements of crystal matrices can be neatly separated in the acquired flood histograms.
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Affiliation(s)
- E Lage
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón. Madrid, Spain
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Lage E, Vaquero JJ, Sisniega A, España S, Tapias G, Abella M, Rodríguez-Ruano A, Ortuño JE, Udías A, Desco M. Design and performance evaluation of a coplanar multimodality scanner for rodent imaging. Phys Med Biol 2009; 54:5427-41. [PMID: 19700817 DOI: 10.1088/0031-9155/54/18/005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This work reports on the development and performance evaluation of the VrPET/CT, a new multimodality scanner with coplanar geometry for in vivo rodent imaging. The scanner design is based on a partial-ring PET system and a small-animal CT assembled on a rotatory gantry without axial displacement between the geometric centers of both fields of view (FOV). We report on the PET system performance based on the NEMA NU-4 protocol; the performance characteristics of the CT component are not included herein. The accuracy of inter-modality alignment and the imaging capability of the whole system are also evaluated on phantom and animal studies. Tangential spatial resolution of PET images ranged between 1.56 mm at the center of the FOV and 2.46 at a radial offset of 3.5 cm. The radial resolution varies from 1.48 mm to 1.88 mm, and the axial resolution from 2.34 mm to 3.38 mm for the same positions. The energy resolution was 16.5% on average for the entire system. The absolute coincidence sensitivity is 2.2% for a 100-700 keV energy window with a 3.8 ns coincident window. The scatter fraction values for the same settings were 11.45% for a mouse-sized phantom and 23.26% for a rat-sized phantom. The peak noise equivalent count rates were also evaluated for those phantoms obtaining 70.8 kcps at 0.66 MBq/cc and 31.5 kcps at 0.11 MBq/cc, respectively. The accuracy of inter-modality alignment is below half the PET resolution, and the image quality of biological specimens agrees with measured performance parameters. The assessment presented in this study shows that the VrPET/CT system is a good performance small-animal imager, while the cost derived from a partial ring detection system is substantially reduced as compared with a full-ring PET tomograph.
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Affiliation(s)
- E Lage
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
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Abstract
Low-pass filtering of sinograms in the radial direction is the most common practice to limit noise amplification in filtered back projection (FBP) reconstruction of positron emission tomography studies. Other filtering strategies have been proposed to prevent the loss in resolution due to low-pass radial filters, although results have been diverse. Using the well-known properties of the Fourier transform of a sinogram, the authors defined a binary mask that matches the expected shape of the support region in the Fourier domain of the sinogram ("bow tie"). This mask was smoothed by a convolution with a ten-point Gaussian kernel which not only avoids ringing but also introduces a pre-emphasis at low frequencies. A new filtering scheme for FBP is proposed, comprising this smoothed bow-tie filter combined with a standard radial filter and an axial filter. The authors compared the performance of the bow-tie filtering scheme with that of other previously reported methods: Standard radial filtering, angular filtering, and stackgram-domain filtering. All the quantitative data in the comparisons refer to a baseline reconstruction using a ramp filter only. When using the smallest size of the Gaussian kernel in the stackgram domain, the authors achieved a noise reduction of 33% at the cost of degrading radial and tangential resolutions (14.5% and 16%, respectively, for cubic interpolation). To reduce the noise by 30%, the angular filter produced a larger degradation of contrast (3%) and tangential resolution (46% at 10 mm from the center of the field of view) and showed noticeable artifacts in the form of circular blurring dependent on the distance to the center of the field of view. For a similar noise reduction (33%), the proposed bow-tie filtering scheme yielded optimum results in resolution (gain in radial resolution of 10%) and contrast (1% increase) when compared with any of the other filters alone. Experiments with rodent images showed noticeable image quality enhancement when using the proposed bow-tie filtering scheme.
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Affiliation(s)
- M Abella
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, 28007 Madrid, Spain
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Abella M, Zubeldia JM, Conejero L, Malpica N, Vaquero JJ, Desco M. Automatic quantification of histological studies in allergic asthma. Cytometry A 2009; 75:271-7. [PMID: 18823007 DOI: 10.1002/cyto.a.20648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The evaluation of new therapies to treat allergic asthma makes frequent use of histological studies. Some of them are based on microscope observation of stained paraffin lung sections to quantify cellular infiltrate, an effect directly related to allergic processes. Currently, there is no software tool available for doing this quantification automatically. This paper presents a methodology and a software tool for the quantification of cellular infiltrate in lung tissue images in an allergic asthma mouse model. The image is divided into regions of equal size, which are then classified by means of a segmentation algorithm based on texture analysis. The classification uses three discriminant functions, built from parameters derived from the histogram and the co-occurrence matrix. These functions were calculated by means of a stepwise discriminant analysis on 79 samples from a training set. Results provided a correct classification of 96.8% on an independent test set of 251 samples labeled manually. Regression analysis showed a good agreement between automatic and manual methods. A reliable and easy to implement method has been developed to provide an automatic method for quantifying microscopy images of lung histological studies. Results showed similar accuracy to that provided by an expert, while allowing analyzing a much larger number of fields in a repeatable way.
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Soto-Montenegro ML, Conejero L, Vaquero JJ, Baeza ML, Zubeldia JM, Desco M. Assessment of airway distribution of transnasal solutions in mice by PET/CT imaging. Mol Imaging Biol 2009; 11:263-8. [PMID: 19340489 DOI: 10.1007/s11307-009-0199-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 09/16/2008] [Accepted: 10/07/2008] [Indexed: 11/28/2022]
Abstract
PURPOSE Transnasal administration is one of the most common routes for allergen challenge in mouse models of airway diseases. Although this technique is widely used, neither the amount of allergen that reaches the lung nor its airway distribution has been well established. We used positron emission tomography (PET) and computed tomography (CT) to examine the anatomical distribution of a solution containing a tracer immediately after transnasal delivery and to determine the possible influence of age and administered volume. PROCEDURES Forty-six female BALB/c mice were divided into three groups according to instillation volume and age: (A) 15 microl, 8-10 weeks old (N = 10), (B) 30 microl, 8-10 weeks old (N = 20), and (C) 30 microl, 32 weeks old (N = 16). Anesthetized animals underwent a dynamic scan in a dedicated small-animal PET scanner immediately after transnasal administration of a solution containing (18)FDG. Regions of interest were used to obtain quantitative data. Animals were also imaged with a small-animal CT scanner to obtain complementary anatomical information. RESULTS Mean +/- SD (5.69 +/- 4.51%) of the solution administered reached the lungs in group A, 41.84 +/- 8.03% in group B, and 36.65 +/- 16.15% in group C. A comparable percentage was delivered to the left and right lungs in all the groups. Analysis of variance revealed a significant difference between the groups in the proportion of the solution that reached the lungs depending on the injection volume (P < 0.001), but not depending on animal age. CONCLUSIONS In this first report on quantitative imaging by PET and CT in small animals, we confirmed the suitability of the transnasal route with an instilled volume of 30 microl delivering fluids into the lower airways, although only about 40% of the dose reaches the lungs.
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Affiliation(s)
- M L Soto-Montenegro
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Dr. Esquerdo, 46, 28007, Madrid, Spain
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España S, Herraiz JL, Vicente E, Vaquero JJ, Desco M, Udias JM. PeneloPET, a Monte Carlo PET simulation tool based on PENELOPE: features and validation. Phys Med Biol 2009; 54:1723-42. [PMID: 19242053 DOI: 10.1088/0031-9155/54/6/021] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [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: 02/07/2023]
Abstract
Monte Carlo simulations play an important role in positron emission tomography (PET) imaging, as an essential tool for the research and development of new scanners and for advanced image reconstruction. PeneloPET, a PET-dedicated Monte Carlo tool, is presented and validated in this work. PeneloPET is based on PENELOPE, a Monte Carlo code for the simulation of the transport in matter of electrons, positrons and photons, with energies from a few hundred eV to 1 GeV. PENELOPE is robust, fast and very accurate, but it may be unfriendly to people not acquainted with the FORTRAN programming language. PeneloPET is an easy-to-use application which allows comprehensive simulations of PET systems within PENELOPE. Complex and realistic simulations can be set by modifying a few simple input text files. Different levels of output data are available for analysis, from sinogram and lines-of-response (LORs) histogramming to fully detailed list mode. These data can be further exploited with the preferred programming language, including ROOT. PeneloPET simulates PET systems based on crystal array blocks coupled to photodetectors and allows the user to define radioactive sources, detectors, shielding and other parts of the scanner. The acquisition chain is simulated in high level detail; for instance, the electronic processing can include pile-up rejection mechanisms and time stamping of events, if desired. This paper describes PeneloPET and shows the results of extensive validations and comparisons of simulations against real measurements from commercial acquisition systems. PeneloPET is being extensively employed to improve the image quality of commercial PET systems and for the development of new ones.
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Affiliation(s)
- S España
- Grupo de Física Nuclear, Departmento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid, Spain
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España S, Herraiz JL, Vicente E, Vaquero JJ, Desco M, Udias JM. PeneloPET, a Monte Carlo PET simulation tool based on PENELOPE: features and validation. Phys Med Biol 2009. [DOI: https://doi.org/10.1088/0031-9155/54/6/021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Soto-Montenegro ML, Vaquero JJ, Pascau J, Gispert JD, García-Barreno P, Desco M. Detection of visual activation in the rat brain using 2-deoxy-2-[(18)F]fluoro-D: -glucose and statistical parametric mapping (SPM). Mol Imaging Biol 2008; 11:94-9. [PMID: 19037612 DOI: 10.1007/s11307-008-0179-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [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: 03/13/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 11/26/2022]
Abstract
PURPOSE This study was designed to assess changes in brain glucose metabolism in rats after visual stimulation. MATERIALS AND METHODS We sought to determine whether visual activation in the rat brain could be detected using a small-animal positron emission tomography (PET) scanner and 2-deoxy-2-[(18)F]fluoro-D: -glucose (FDG). Eleven rats were divided into two groups: (a) five animals exposed to ambient light and (b) six animals stimulated by stroboscopic light (10 Hz) with one eye covered. Rats were injected with FDG and, after 45 min of visual stimulation, were sacrificed and scanned for 90 min in a dedicated PET tomograph. Images were reconstructed by a three-dimensional ordered subset expectation maximization algorithm (1.8 mm full width at half maximum). A region-of-interest (ROI) analysis was performed on 14 brain structures drawn on coronal sections. Statistical parametric mapping (SPM) adapted for small animals was also carried out. Additionally, the brains of three rats were sliced into 20-microm sections for autoradiography. RESULTS Analysis of ROI data revealed significant differences between groups in the right superior colliculus, right thalamus, and brainstem (p < or = 0.05). SPM detected the same areas as the ROI approach. Autoradiographs confirmed the existence of hyperactivation in the left superior colliculus and auditory cortex. CONCLUSIONS To our knowledge, this is the first report that uses FDG-PET and SPM analysis to show changes in rat brain glucose metabolism after a visual stimulus.
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Affiliation(s)
- M L Soto-Montenegro
- Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Marañón, C/Dr. Esquerdo, 46, Madrid, 28007, Spain
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Casado JA, Río P, Marco E, García-Hernández V, Domingo A, Pérez L, Tercero JC, Vaquero JJ, Albella B, Gago F, Bueren JA. Relevance of the Fanconi anemia pathway in the response of human cells to trabectedin. Mol Cancer Ther 2008; 7:1309-18. [PMID: 18483318 DOI: 10.1158/1535-7163.mct-07-2432] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Trabectedin (Yondelis; ET-743) is a potent anticancer drug that binds to DNA by forming a covalent bond with a guanine in one strand and one or more hydrogen bonds with the opposite strand. Using a fluorescence-based melting assay, we show that one single trabectedin-DNA adduct increases the thermal stability of the double helix by >20 degrees C. As deduced from the analysis of phosphorylated H2AX and Rad51 foci, we observed that clinically relevant doses of trabectedin induce the formation of DNA double-strand breaks in human cells and activate homologous recombination repair in a manner similar to that evoked by the DNA interstrand cross-linking agent mitomycin C (MMC). Because one important characteristic of this drug is its marked cytotoxicity on cells lacking a functional Fanconi anemia (FA) pathway, we compared the response of different subtypes of FA cells to MMC and trabectedin. Our data clearly show that human cells with mutations in FANCA, FANCC, FANCF, FANCG, or FANCD1 genes are highly sensitive to both MMC and trabectedin. However, in marked contrast to MMC, trabectedin does not induce any significant accumulation of FA cells in G2-M. The critical relevance of FA proteins in the response of human cells to trabectedin reported herein, together with observations showing the role of the FA pathway in cancer suppression, strongly suggest that screening for mutations in FA genes may facilitate the identification of tumors displaying enhanced sensitivity to this novel anticancer drug.
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Affiliation(s)
- José A Casado
- Division of Hematopoiesis and Gene Therapy Program, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Avenida Complutense 22, 28040 Madrid, Spain
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Chavarrías C, Vaquero JJ, Sisniega A, Rodríguez-Ruano A, Soto-Montenegro ML, García-Barreno P, Desco M. Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method. Phys Med Biol 2008; 53:4683-95. [DOI: 10.1088/0031-9155/53/17/015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pascau J, Gispert JD, Michaelides M, Thanos PK, Volkow ND, Vaquero JJ, Soto-Montenegro ML, Desco M. Automated method for small-animal PET image registration with intrinsic validation. Mol Imaging Biol 2008; 11:107-13. [PMID: 18670824 DOI: 10.1007/s11307-008-0166-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 04/18/2008] [Accepted: 05/01/2008] [Indexed: 11/24/2022]
Abstract
PURPOSE We propose and compare different registration approaches to align small-animal PET studies and a procedure to validate the results by means of objective registration consistency measurements. PROCEDURES We have applied a registration algorithm based on information theory, using different approaches to mask the reference image. The registration consistency allows for the detection of incorrect registrations. This methodology has been evaluated on a test dataset (FDG-PET rat brain images). RESULTS The results show that a multiresolution two-step registration approach based on the use of the whole image at the low resolution step, while masking the brain at the high resolution step, provides the best robustness (87.5% registration success) and highest accuracy (0.67-mm average). CONCLUSIONS The major advantages of our approach are minimal user interaction and automatic assessment of the registration error, avoiding visual inspection of the results, thus facilitating the accurate, objective, and rapid analysis of large groups of rodent PET images.
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Affiliation(s)
- Javier Pascau
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, C/ Doctor Esquerdo 46, 28007, Madrid, Spain.
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Higuera-Matas A, Soto-Montenegro ML, del Olmo N, Miguéns M, Torres I, Vaquero JJ, Sánchez J, García-Lecumberri C, Desco M, Ambrosio E. Augmented acquisition of cocaine self-administration and altered brain glucose metabolism in adult female but not male rats exposed to a cannabinoid agonist during adolescence. Neuropsychopharmacology 2008; 33:806-13. [PMID: 17551541 DOI: 10.1038/sj.npp.1301467] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Marijuana consumption during adolescence has been proposed to be a stepping-stone for adult cocaine addiction. However, experimental evidence for this hypothesis is missing. In this work we chronically injected male and female Wistar rats with either the cannabinoid agonist CP 55,940 (CP; 0.4 mg/kg) or its corresponding vehicle. Adult acquisition (seven 30 min daily sessions) and maintenance (fourteen 2 h daily sessions) of cocaine self-administration (1 mg/kg), food-reinforced operant learning under conditions of normal (ad libitum access to food), and high motivation (food-restriction schedule) were measured. Additionally, brain metabolic activity was analyzed by means of [(18)F]-fluorodeoxyglucose positron emission tomography. During the acquisition phase, female CP-treated rats showed a higher rate of cocaine self-administration as compared to vehicle-treated females and males; no differences were found between both male groups. This effect disappeared in the maintenance phase. Moreover, no differences among groups were evident in the food-reinforced operant task, pointing to the cocaine-specific nature of the effect seen in self-administration rather than a general change in reward processing. Basal brain metabolic activity also changed in CP-treated females when compared to their vehicle-treated counterparts with no differences being found in the males; more specifically we observed a hyper activation of the frontal cortex and a hypo activation of the amygdalo-entorhinal cortex. Our results suggest that a chronic exposure to cannabinoids during adolescence alters the susceptibility to acquire cocaine self-administration, in a sex-specific fashion. This increased susceptibility could be related to the changes in brain metabolic activity induced by cannabinoids during adolescence.
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Affiliation(s)
- Alejandro Higuera-Matas
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educacion a Distancia, Madrid, Spain
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Cano J, Campo J, Vaquero JJ, Martínez González JM, Bascones A. High resolution image in bone biology II. Review of the literature. Med Oral Patol Oral Cir Bucal 2008; 13:E31-E35. [PMID: 18167477] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Bone microstructure has usually been assessed by obtaining samples invasively and analyzing them with conventional histomorphometric methods. Improvements in high-resolution image acquisition systems have enabled non-invasive assessment of bone morphology and a more precise 3-D evaluation by means of "virtual biopsies", permitting bone assessment in regeneration or remodeling processes. Among other applications, this imaging technique can be used for the ultrastructural analysis of bone and for studies of regeneration techniques, biomechanics in bone physiotherapy, and periimplant bone healing. This review describes the different applications of high-resolution imaging techniques in bone biology and the morphometric results obtained with these images in mechanobiology in general and maxillary bone in particular.
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Affiliation(s)
- Jorge Cano
- School of Dentistry, UCM, Madrid, Spain.
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Cano J, Campo J, Vaquero JJ, Martínez JM, Bascones A. High resolution image in bone biology I. Review of the literature. Med Oral Patol Oral Cir Bucal 2007; 12:E454-8. [PMID: 17909513] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Bone microstructure has usually been assessed by obtaining samples invasively and analyzing them with conventional histomorphometric methods. Improvements in high-resolution image acquisition systems have enabled non-invasive assessment of bone morphology and a more precise 3-D evaluation by means of "virtual biopsies", permitting bone assessment in regeneration or remodeling processes. This review describes the characteristics and limitations of bone assessment using different high-resolution image systems (synchrotron-radiation computed tomography, micro-computed tomography, acoustic scanning microscope; micro-magnetic resonance imaging). Morphometric variables that can be obtained from these images are reported and compared with conventional histomorphometric variables.
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Negri A, Marco E, García-Hernández V, Domingo A, Llamas-Saiz AL, Porto-Sandá S, Riguera R, Laine W, David-Cordonnier MH, Bailly C, García-Fernández LF, Vaquero JJ, Gago F. Antitumor Activity, X-ray Crystal Structure, and DNA Binding Properties of Thiocoraline A, a Natural Bisintercalating Thiodepsipeptide. J Med Chem 2007; 50:3322-33. [PMID: 17571868 DOI: 10.1021/jm070381s] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [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: 11/29/2022]
Abstract
The marine natural product thiocoraline A displayed approximately equal cytotoxic activity at nanomolar concentrations in a panel of 12 human cancer cell lines. X-ray diffraction analyses of orthorhombic crystals of this DNA-binding drug revealed arrays of docked pairs of staple-shaped molecules in which one pendent hydroxyquinoline chromophore from each cysteine-rich molecule appears intercalated between the two chromophores of a facing molecule. This arrangement is in contrast to the proposed mode of binding to DNA that shows the two drug chromophores clamping two stacked base pairs, in agreement with the nearest-neighbor exclusion principle. Proof of DNA sequence recognition was obtained from both classical DNase I footprinting experiments and determination of the melting temperatures of several custom-designed fluorescently labeled oligonucleotides. A rationale for the DNA-binding behavior was gained when models of thiocoraline clamping a central step embedded in several octanucleotides were built and studied by means of unrestrained molecular dynamics simulations in aqueous solution.
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Affiliation(s)
- Ana Negri
- Departamento de Farmacología, Universidad de AlcalA, E-28871 Madrid, Spain
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Soto-Montenegro ML, Vaquero JJ, Arango C, Ricaurte G, García-Barreno P, Desco M. Effects of MDMA on blood glucose levels and brain glucose metabolism. Eur J Nucl Med Mol Imaging 2007; 34:916-25. [PMID: 17219137 DOI: 10.1007/s00259-006-0262-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [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: 05/03/2006] [Accepted: 08/08/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE This study was designed to assess changes in glucose metabolism in rats administered single or repeated doses of MDMA. METHODS Two different experiments were performed: (1) A single-dose study with four groups receiving 20 mg/kg, 40 mg/kg, saline or heat, and (2) a repeated-dose study with two groups receiving three doses, at intervals of 2 h, of 5 mg/kg or saline. Rats were imaged using a dedicated small-animal PET scanner 1 h after single-dose administration or 7 days after repeated doses. Glucose metabolism was measured in 12 cerebral regions of interest. Rectal temperature and blood glucose were monitored. RESULTS Peak body temperature was reached 1 h after MDMA administration. Blood glucose levels decreased significantly after MDMA administration. In the single-dose experiment, brain glucose metabolism showed hyperactivation in cerebellum and hypo-activation in the hippocampus, amygdala and auditory cortex. In the repeated-dose experiment, brain glucose metabolism did not show any significant change at day 7. CONCLUSION These results are the first to indicate that MDMA has the potential to produce significant hypoglycaemia. In addition, they show that MDMA alters glucose metabolism in components of the motor, limbic and somatosensory systems acutely but not on a long-term basis.
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Affiliation(s)
- M L Soto-Montenegro
- Laboratorio de Imagen, Medicina Experimental, Hospital General Universitario Gregorio Marañon, Dr. Esquerdo, 46, 28007, Madrid, Spain
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Abstract
Small animal PET scanners require high spatial resolution and good sensitivity. To reconstruct high-resolution images in 3D-PET, iterative methods, such as OSEM, are superior to analytical reconstruction algorithms, although their high computational cost is still a serious drawback. The higher performance of modern computers could make iterative image reconstruction fast enough to be viable, provided we are able to deal with the large number of probability coefficients for the system response matrix in high-resolution PET scanners, which is a difficult task that prevents the algorithms from reaching peak computing performance. Considering all possible axial and in-plane symmetries, as well as certain quasi-symmetries, we have been able to reduce the memory requirements to store the system response matrix (SRM) well below 1 GB, which allows us to keep the whole response matrix of the system inside RAM of ordinary industry-standard computers, so that the reconstruction algorithm can achieve near peak performance. The elements of the SRM are stored as cubic spline profiles and matched to voxel size during reconstruction. In this way, the advantages of 'on-the-fly' calculation and of fully stored SRM are combined. The on-the-fly part of the calculation (matching the profile functions to voxel size) of the SRM accounts for 10-30% of the reconstruction time, depending on the number of voxels chosen. We tested our approach with real data from a commercial small animal PET scanner. The results (image quality and reconstruction time) show that the proposed technique is a feasible solution.
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Affiliation(s)
- J L Herraiz
- Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Spain
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