Alvaro Ruibal

Alvaro Ruibal
University of Santiago de Compostela | USC

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474
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Publications

Publications (474)
Article
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The aim is to evaluate the diagnostic yield of echocardiography and [⁹⁹mTc]Tc-DPD scintigraphy in the detection of amyloid cardiomyopathy (CM) and define potential prognostic echocardiographic parameters. 133 patients were retrospectively studied, from 2016 to 2021, with a mean age of 80.2 ± 7.5 years. The final diagnosis was established according...
Article
Aim: Systemic inflammatory factors have been validated as indicators of ongoing systemic inflammation that could be predictive markers of poor prognosis for oncological outcomes. However, the prognostic impact of systemic inflammation markers is unknown in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) treated with peptide r...
Article
Background: Bone tracers such as99mTc-DPD have shown high sensitivity and specificity in the non-invasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CA). This study aims to validate SPECT/CT and assess the usefulness of uptake quantification (DPDload) in the myocardial tissue as potential information on the amyloid burden. Methods: In...
Article
Aim Systemic inflammatory factors have been validated as indicators of ongoing systemic inflammation that could be predictive markers of poor prognosis for oncological outcomes. However, the prognostic impact of systemic inflammation markers is unknown in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) treated with peptide rec...
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Purpose Recent evidence suggests that PET imaging with amyloid-β (Aβ) tracers can be used to assess myelin integrity in cerebral white matter (WM). Alzheimer’s disease (AD) is characterized by myelin changes that are believed to occur early in the disease course. Nevertheless, the extent to which demyelination, as measured with Aβ PET, contributes...
Preprint
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Purpose: To obtain individualized internal doses with a Monte Carlo method in patients undergoing diagnostic FCH-PET studies and to compare such doses with the MIRD method calculations. Methods: A patient cohort of 17 males were imaged after intravenous administration of a mean FCH activity of 244.3 MBq. The resulting PET/CT images were processed i...
Article
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Purpose To obtain individualized internal doses with a Monte Carlo (MC) method in patients undergoing diagnostic [18F]FCH‐PET studies and to compare such doses with the MIRD method calculations. Methods A patient cohort of 17 males were imaged after intravenous administration of a mean [18F]FCH activity of 244.3 MBq. The resulting PET/CT images we...
Article
Resumen Antecedentes Estudiar la posible relación entre la expresión inmunohistoquímica del receptor 1 del factor de crecimiento endotelial vascular (VEGFR1) y el valor máximo de captación estandarizada (SUVmáx) de la PET ¹⁸F-FDG en pacientes con cáncer de pulmón de células no pequeñas. Material y métodos El estudio incluyó 39 pacientes con NSCLC...
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Purpose SimPET (www.sim‐pet.org) is a free cloud‐based platform for the generation of realistic brain positron emission tomography (PET) data. In this work, we introduce the key features of the platform. In addition, we validate the platform by performing a comparison between simulated healthy brain FDG‐PET images and real healthy subject data for...
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Background: Although many works have supported the utility of PET radiomics, several authors have raised concerns over the robustness and replicability of the results. This study aimed to perform a systematic review on the topic of PET radiomics and the used methodologies. Methods: PubMed was searched up to 15 October 2020. Original research art...
Preprint
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Purpose: Recent evidence suggest that PET imaging with amyloid-β (Aβ) tracers can be used to assess myelin integrity in cerebral white matter (WM). Alzheimer’s disease (AD) is characterized by myelin changes that are believed to occur early in the disease course. Nevertheless, the extent to which demyelination, as measured with Aβ PET, contributes...
Article
Background To study the possible relation between immunohistochemical expression of vascular endothelial growth factor receptor 1 (VEGFR1) and the maximum standardised uptake value (SUV max) of ¹⁸F-FDG PET in patients with non small cell lung cancer (NSCLC). Material and Methods The study included 39 patients with NSCLC (24 squamous cell carcinoma...
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A Correction to this paper has been published: https://doi.org/10.1007/s00330-020-07619-6
Article
Intracerebral hemorrhage (ICH), being the most severe cerebrovascular disease, accounts for 10-15% of all strokes. Hematoma expansion is one of the most important factors associated with poor outcome in intracerebral hemorrhage (ICH). Several studies have suggested that an "ischemic penumbra" might arise when the hematoma has a large expansion, but...
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The aim of this study was to fabricate novel self-supporting tacrolimus suppositories using semisolid extrusion 3-dimensional printing (3DP) and to investigate their efficacy in an experimental model of inflammatory bowel disease. Blends of Gelucire 44/14 and coconut oil were employed as lipid excipients to obtain suppository formulations with self...
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Objectives: We aimed at investigating the origin of the correlations between tumor volume and 18 F-FDG-PET texture indices in lung cancer. Methods: Eighty-five consecutive patients with newly diagnosed non-small cell lung cancer (NSCLC) underwent a 18 F-FDG-PET/CT scan before treatment. Seven phantom spheres uniformly filled with 18 F-FDG, and cov...
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Purpose: Preclinical dynamic brain PET studies remain hampered by the limitations related to the measurement of the arterial input function (AIF). In this regard, the use of an arterial-venous shunt is a promising method for the generation of real-time AIFs, but its application in longitudinal studies is still impeded by the cumbersome surgeries an...
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Background The lack of standardization of the intensity normalization methods and its unknown effect on quantification output is recognized as a major drawback for the harmonization of brain FDG-PET quantification protocols. The aim of this work is the ground truth-based evaluation of different intensity normalization methods on brain FDG-PET quant...
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Purpose The purpose of this work is to calculate individualized dose distributions in patients undergoing ¹⁸F‐FDG PET/CT studies through a methodology based on full Monte Carlo (MC) simulations and PET/CT patient images, and to compare such values with those obtained by employing nonindividualized phantom‐based methods. Methods We developed a MC‐b...
Article
Intravitreal injections are the standard procedure in the treatment of retinal pathologies, such as the administration of the anti-VEGF antibodies in age-related macular degeneration. The aim of this study is to evaluate the intraocular and blood pharmacokinetics after an intravitreal injection of ⁸⁹Zr-labelled bevacizumab and ⁸⁹Zr-labelled afliber...
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The association between white matter hyperintensities (WMH) and amyloid accumulation over time in cognitively normal, amyloid-negative elderly people remains largely unexplored. In order to study whether baseline WMH were associated with longitudinal subthreshold amyloid accumulation, 159 cognitively normal participants from the Alzheimer’s Disease...
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Background: 177Lu peptide receptor radionuclide therapy (PRRT) is a recently approved therapy in Spain that has been demonstrated to be a well-tolerated therapy for positive somatostatin receptor advanced gastroenteropancreatic neuroendocrine tumors. Aim: To determine the impact of PRRT on quality of life, radiologic and metabolic response, over...
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Introduction: The early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG PET) in the diagnosis of this disease. Materials and metho...
Article
Inflammatory Bowel Disease (IBD) is a group of chronic disorders of the gastrointestinal tract, which two main types are Crohn’s disease and ulcerative colitis. Although conventional therapeutic strategies have demonstrated to be effective in the IBD treatment, it is necessary to incorporate novel therapeutic agents that target other mechanisms inv...
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Introduction The early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [¹⁸F]2-fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET) in the diagnosis of this disease. Materials and Methods...
Article
It is unclear whether episodic memory is an appropriate descriptor of the cognitive continuum in mild cognitive impairment (MCI). Here, we investigated the ability of episodic memory to track cognitive changes in patients with MCI with biomarker evidence of Alzheimer's disease (AD). We examined 387 MCI amyloid-positive subjects, cognitively staged...
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Classical methodologies used in ocular pharmacokinetics studies have difficulties to obtain information about topical and intraocular distribution and clearance of drugs and formulations. This is associated with multiple factors related to ophthalmic physiology, as well as the complexity and invasiveness intrinsic to the sampling. Molecular imaging...
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Magnetic resonance imaging (MRI) volumetric measures have become a standard tool for the detection of incipient Alzheimer's Disease (AD) dementia in mild cognitive impairment (MCI). Focused on providing an earlier and more accurate diagnosis, sophisticated MRI machine learning algorithms have been developed over the recent years, most of them learn...
Chapter
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Inflammatory bowel disease (IBD) is a group of chronic disorders of the gastrointestinal (GI) tract, which two main types are Crohn´s disease (CD) and ulcerative colitis (UC). The exact causes of IBD still remain unknown but are accepted to be multifactorial. For this reason, the use of animal models of IBD is gaining importance in preclinical rese...
Article
Purpose: To evaluate the diagnostic value of dedicated breast PET (dbPET) parallel imaging in mammographically or sonographically detected BI-RADS 4 (Breast Imaging Reporting And Data Systems) lesions. Materials and methods: After institutional review board and patient approvals, 50 consecutive women with 60 BI-RADS 4 breast lesions were prospectiv...
Article
Inflammatory bowel disease (IBD) is a group of chronic disorders of the gastrointestinal tract, which two main types are Crohńs disease and ulcerative colitis. It has multifactorial etiologies, being essential the use of animal models and disease activity measures to develop new therapies. With this aim, the use of animal models in combination with...
Article
Severe allergic ocular diseases as atopic keratoconjunctivitis can induce corneal damage due to inflammatory substances released from giant papillae. Tacrolimus eye drops are one of the current therapeutic alternatives for its treatment. This work is aimed at developing and characterizing a 0.03% tacrolimus ophthalmic formulation, which was introdu...
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PURPOSE: This study aims to determine whether PET textural features measured with a new dedicated breast PET scanner reflect biological characteristics of breast tumors. METHODS: One hundred and thirty-nine breast tumors from 127 consecutive patients were included in this analysis. All of them underwent a 18F-FDG PET scan before treatment. Well-kn...
Article
Celia's encephalopathy (progressive encephalopathy with/without lipodystrophy, PELD) is a recessive neurodegenerative disease that is fatal in childhood. It is caused by a c.985C>T variant in the BSCL2/seipin gene that results in an aberrant seipin protein. We evaluated neurological development before and during treatment with human recombinant lep...
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Purpose: This work aimed at describing the time course of vitreous clearance through the use of positron emission tomography (PET) as a noninvasive tool for pharmacokinetic studies of intravitreal injection. Methods: The pharmacokinetic profile of intravitreal injections of molecules labeled with 18Fluorine (18F) was evaluated in adult Sprague D...
Article
Purpose The aim of this work is to study the effect of physiological muscular uptake variations and statistical noise on tumor quantification in FDG-PET studies. Methods We designed a realistic framework based on simulated FDG-PET acquisitions from an anthropomorphic phantom that included different muscular uptake levels and three spherical lung le...
Article
Purpose: This work is aimed at describing the utility of positron emission tomography/computed tomography (PET/CT) as a noninvasive tool for pharmacokinetic studies of biopermanence of topical ocular formulations. Methods: The corneal biopermanence of a topical ophthalmic formulation containing gellan gum and kappa carragenan (0.82% wt/vol) labe...
Article
In last years, sensitive hydrogels have become a breakthrough in ophthalmic pharmaceutical technology aimed at developing new strategies to increase the residence time of active substances. In a previous paper, we qualitatively demonstrated the capacity of a new ion sensitive hydrogel to increase the residence time. Nevertheless, the clearance of t...
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Background: The spinocerebellar ataxias (SCAs) form a clinically, genetically, and pathological heterogeneous group of autosomal-dominant degenerative diseases. In particular, SCA36 is characterized by a late-onset, slowly progressive cerebellar syndrome typically associated with sensorineural hearing loss. This study was aimed at analyzing the ne...
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Introduction: We analyzed the behavior of certain clinical and biological aspects in breast invasive ductal carcinomas (IDC) when tumor size increased up to three centimeters
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A 49 year-old woman diagnosed with infiltrating lobular breast carcinoma, underwent a right mastectomy and sentinel node biopsy (SLNB). The resected sentinel lymph nodes were negative for malignancy, with an axillary lymphadenectomy not being performed. In the early post-operative period, the patient reported an axillary skin tension sensation, ass...
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Introduction: Current guidelines for brain PET imaging advice against the injection of diazepam prior to brain FDG-PET examination in order to avoid possible interactions of benzodiazepines with the radiotracer uptake. Nevertheless, many patients undergoing PET studies are likely to be under chronic treatment with benzodiazepines, for example due...
Article
The last recommendations of the International Commission on Radiological Protection for eye lens dose suggest an important reduction on the radiation limits associated with early and late tissue reactions. The aim of this work is to quantify and optimize the eye lens dose associated to nurse staff during positron emission tomography (PET) procedure...
Article
Background: The aim of this study was to develop a method for estimating DMSA SPECT renal function on each renal pole in order to evaluate the effect of percutaneous nephrolithotripsy by focusing the measurements on the region through which the percutaneous approach is performed. Methods: Twenty patients undergoing percutaneous nephrolithotripsy...
Article
A 49 year-old woman diagnosed with infiltrating lobular breast carcinoma, underwent a right mastectomy and sentinel node biopsy (SLNB). The resected sentinel lymph nodes were negative for malignancy, with an axillary lymphadenectomy not being performed. In the early post-operative period, the patient reported an axillary skin tension sensation, ass...
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Full-text available
Background/aim: Invasive lobular breast carcinoma is the second most common type of breast cancer after invasive ductal carcinoma. According to the American Cancer Society, more than 180,000 women in the United States find out they have invasive breast cancer each year. Personal history of breast cancer and certain changes in the breast are correl...
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The spill-in counts from neighbouring regions can significantly bias the quantification over small regions close to high activity extended sources. This effect can be a drawback for (18)F-based radiotracers positron emission tomography (PET) when quantitatively evaluating the bladder area for diseases such as prostate cancer. In this work, we use M...
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This study was conducted to investigate the clinicopathological parameters in elderly women (aged >70 years) with infiltrating lobular carcinoma (ILC) of the breast and compare the results with those obtained from younger patients (aged 55-70 years). The study sample included a total of 46 women with ILCs, 10 aged >70 and 36 aged 55-70 years. The p...
Article
BACKGROUND. Continued progress in the control of breast cancer will require sustained efforts to provide high-quality screening, diagnosis, and treatment to all segments of the population. MRI has the advantages of providing a 3D view of the breast with high sensitivity, using non-ionizing radiation. However, MRI has significant limitations includi...
Article
Background: Breast cancer is one of the most common cancers in women. Approximately 232,670 new cases of breast cancer (14% of all new cancer cases) and 40,000 breast cancer deaths (6,8% of all cancer deaths) are expected to occur among US women in 2014. Since 1990, breast cancer death rates have dropped by 34%. Continued progress in the control of...
Article
A 65-year-old male presented with unexplained hypoxia that became exacerbated by an upright posture (platypnea-orthodeoxia syndrome) secondary to hepatopulmonary syndrome (HPS). A (99m)Tc-macroaggregated albumin pulmonary perfusion scan revealed a right to left shunt of 29% in the sitting position, which had not been previously detected when the ra...
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Glioblastoma multiforme (GBM) is the most common brain tumor in adults. The role of high in normal-1 (HIN-1) as a potential biomarker in combating this disease is being described for the first time in this study. A combination of O6-methylguanine DNA methyltransferase (MGMT) and HIN-1 methylation could be a possible biomarker in therapy choice. Int...
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Membranous CD44v6 levels in tumors and surrounding samples obtained from 94 patients with squamous cell lung carcinomas were studied and compared to clinical stage, cellular proliferation, membranous CD44v5 levels, epidermal growth factor receptor EGFR and cytoplasmatic concentrations of CYFRA 21.1. CD44v6 positive values were observed in 33/38 non...
Article
In preclinical research, the growing number of transgenic models has led to the need for renal-function studies in mice. Many efforts have been made to develop dedicated SPECT systems for rodents, but their availability is limited due to high capital costs. The aim of this work is to demonstrate the feasibility of mouse renal imaging by using an in...
Article
To study the clinical and biological (cellular proliferation and hormone-dependence) associations during the progression of histological grade (HG), from HG1 to HG3, in invasive ductal carcinomas of the breast (IDC) <1 cm. The study group included 119 women with IDCs ≤1 cm, aged between 27 and 88 years (median=61 years). The parameters analyzed wer...
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It is well-known that in pinhole SPECT (single-photon-emission computed tomography), iterative reconstruction methods including accurate estimations of the system response matrix can lead to submillimeter spatial resolution. There are two different methods for obtaining the system response matrix: those that model the system analytically using an a...
Article
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Glioblastoma multiforme (GBM) is the most frequent and malignant astrocytic glioma in the adult, with a survival rate at 5years less than 5%. In the GBM pathogenesis, the importance of genes methylation involved in cell cycle, tumor suppression, DNA repair and genome integrity, as well as tumor invasion and apoptosis has been described. We analyzed...
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Breast cancer is currently becoming a disease of the elderly. We have studied the relation between CA 15.3 serum concentrations and clinical-pathological parameters in 69 women with IDC aged over 70 years (76.3 ± 4.2; range: 71-88; median 76). A group of 205 women with the same tumor but aged <70 years (62.8 ± 4.0; range: 55-70; median 63) was also...
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To study the immunohistochemical expression of bcl-2 in patients with hormone-independent breast infiltrating ductal carcinomas (IDC) and its possible association with other clinico-biological parameters and outcome. Our study group included 72 females with hormone-independent (ER and PgR negative) infiltrating ductal breast carcinomas. Age, tumor...
Article
Objetivo estudiar en detalle la precisión y la repetitividad de tres métodos de uso común en la estimación del SUV de nódulos pulmonares solitarios. Material y métodos hemos diseñado una metodología de trabajo basada en la simulación de adquisiciones de estudios PET-FDG a partir de modelos antropomórficos de actividad, que incluyen nódulos pulmona...
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To assess the functional effects of percutaneous nephrolithotomy (PCNL) and its outcomes in the operated kidney, we prospectively studied 30 consecutive cases undergoing PCNL. Kidney function was evaluated preoperatively and 3 months after surgery with serum creatinine, glomerular filtration rate (GFR), and with (99m)Tc-DMSA SPECT-CT scans to deter...
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Molecular imaging is reshaping clinical practice in the last decades, providing practitioners with non-invasive ways to obtain functional in-vivo information on a diversity of relevant biological processes. The use of molecular imaging techniques in preclinical research is equally beneficial, but spreads more slowly due to the difficulties to justi...
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The traditional lack of techniques suitable for in vivo imaging has induced a great interest in molecular imaging for preclinical research. Nevertheless, its use spreads slowly due to the difficulties in justifying the high cost of the current dedicated preclinical scanners. An alternative for lowering the costs is to repurpose old clinical gamma c...
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Current procedure guidelines for whole body [18F]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) state that studies with visible dose extravasations should be rejected for quantification protocols. Our work is focused on the development and validation of methods for estimating extravasated doses in order to correct standard uptake...