In vivo morphometric and mechanical characterization of trabecular bone from high resolution magnetic resonance imaging

La osteoporosis es una enfermedad ósea que se manifiesta con una menor densidad ósea y el deterioro de la arquitectura del hueso esponjoso. Ambos factores aumentan la fragilidad ósea y el riesgo de sufrir fracturas óseas, especialmente en mujeres, donde existe una alta prevalencia. El diagnóstico actual de la osteoporosis se basa en la cuantificación de la densidad mineral ósea (DMO) mediante la técnica de absorciometría dual de rayos X (DXA). Sin embargo, la DMO no puede considerarse de manera aislada para la evaluación del riesgo de fractura o los efectos terapéuticos. Existen otros factores, tales como la disposición microestructural de las trabéculas y sus características que es necesario tener en cuenta para determinar la calidad del hueso y evaluar de manera más directa el riesgo de fractura. Los avances técnicos de las modalidades de imagen médica, como la tomografía computarizada multidetector (MDCT), la tomografía computarizada periférica cuantitativa (HR-pQCT) y la resonancia magnética (RM) han permitido la adquisición in vivo con resoluciones espaciales elevadas. La estructura del hueso trabecular puede observarse con un buen detalle empleando estas técnicas. En particular, el uso de los equipos de RM de 3 Teslas (T) ha permitido la adquisición con resoluciones espaciales muy altas. Además, el buen contraste entre hueso y médula que proporcionan las imágenes de RM, así como la utilización de radiaciones no ionizantes sitúan a la RM como una técnica muy adecuada para la caracterización in vivo de hueso trabecular en la enfermedad de la osteoporosis. En la presente tesis se proponen nuevos desarrollos metodológicos para la caracterización morfométrica y mecánica del hueso trabecular en tres dimensiones (3D) y se aplican a adquisiciones de RM de 3T con alta resolución espacial. El análisis morfométrico está compuesto por diferentes algoritmos diseñados para cuantificar la morfología, la complejidad, la topología y los parámetros de anisotropía del tejido trabecular. En cuanto a la caracterización mecánica, se desarrollaron nuevos métodos que permiten la simulación automatizada de la estructura del hueso trabecular en condiciones de compresión y el cálculo del módulo de elasticidad. La metodología desarrollada se ha aplicado a una población de sujetos sanos con el fin de obtener los valores de normalidad del hueso esponjoso. Los algoritmos se han aplicado también a una población de pacientes con osteoporosis con el fin de cuantificar las variaciones de los parámetros en la enfermedad y evaluar las diferencias con los resultados obtenidos en un grupo de sujetos sanos con edad similar.Los desarrollos metodológicos propuestos y las aplicaciones clínicas proporcionan resultados satisfactorios, presentando los parámetros una alta sensibilidad a variaciones de la estructura trabecular principalmente influenciadas por el sexo y el estado de enfermedad. Por otra parte, los métodos presentan elevada reproducibilidad y precisión en la cuantificación de los valores morfométricos y mecánicos. Estos resultados refuerzan el uso de los parámetros presentados como posibles biomarcadores de imagen en la enfermedad de la osteoporosis.Alberich Bayarri, Á. (2010). In vivo morphometric and mechanical characterization of trabecular bone from high resolution magnetic resonance imaging [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8981Palanci

Optimisation of ultrasound liver perfusion through a digital reference object and analysis tool

[EN] Background Conventional ultrasound (US) provides important qualitative information, although there is a need to evaluate the influence of the input parameters on the output signal and standardise the acquisition for an adequate quantitative perfusion assessment. The present study analyses how the variation in the input parameters influences the measurement of the perfusion parameters. Methods A software tool with simulator of the conventional US signal was created, and the influence of the different input variables on the derived biomarkers was analysed by varying the image acquisition configuration. The input parameters considered were the dynamic range, gain, and frequency of the transducer. Their influence on mean transit time (MTT), the area under the curve (AUC), maximum intensity (MI), and time to peak (TTP) parameters as outputs of the quantitative perfusion analysis was evaluated. A group of 13 patients with hepatocarcinoma was analysed with both a commercial tool and an in-house developed software. Results The optimal calculated inputs which minimise errors while preserving images¿ readability consisted of gain of 15¿dB, dynamic range of 60¿dB, and frequency of 1.5¿MHz. The comparison between the in-house developed software and the commercial software provided different values for MTT and AUC, while MI and TTP were highly similar. Conclusion Input parameter selection introduces variability and errors in US perfusion parameter estimation. Our results may add relevant insight into the current knowledge of conventional US perfusion and its use in lesions characterisation, playing in favour of optimised standardised parameter configuration to minimise variability.Alberich-Bayarri, Á.; Tomás-Cucarella, J.; Torregrosa-Lloret, A.; Saiz Rodríguez, FJ.; Martí-Bonmatí, L. (2019). Optimisation of ultrasound liver perfusion through a digital reference object and analysis tool. European Radiology Experimental. 3:1-10. https://doi.org/10.1186/s41747-019-0086-5S1103Parker JM, Weller MW, Feinstein LM et al (2013) Safety of ultrasound contrast agents in patients with known or suspected cardiac shunts. Am J Cardiol 112:1039–1045.Dhamija E, Paul SB (2014) Role of contrast enhanced ultrasound in hepatic imaging. Trop Gastroenterol 35:141–151.Wang XY, Kang LK, Lan CY (2014) Contrast-enhanced ultrasonography in diagnosis of benign and malignant breast lesions. Eur J Gynaecol Oncol 35:415–420.Wang S, Yang W, Zhang H, Xu Q, Yan K (2015) The role of contrast-enhanced ultrasound in selection indication and improveing diagnosis for transthoracic biopsy in peripheral pulmonary and mediastinal lesions. Biomed Res Int 2015:231782.Green MA, Mathias CJ, Willis LR, et al (2007) Assessment of Cu-ETS as a PET radiopharmaceutical for evaluation of regional renal perfusion. Nucl Med Biol 34:247–255.Daghini E, Primak AN, Chade AR, et al (2007) Assessment of renal hemodynamics and function in pigs with 64-section multidetector CT: comparison with electron-beam CT. Radiology 243:405–412.Martin DR, Sharma P, Salman K, et al (2008) Individual kidney blood flow measured with contrast-enhanced first-pass perfusion MR imaging. Radiology 246:241–248.Tang MX, Mulvana H, Gauthier T, et al (2011) Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability. Interface Focus 1:520–539.Gauthier TP, Averkiou MA, Leen EL (2011) Perfusion quantification using dynamic contrast-enhanced ultrasound: the impact of dynamic range and gain on time-intensity curves. Ultrasonics 51:102–106.Möller I, Janta I, Backhaus M, et al (2017) The 2017 EULAR standardised procedures for ultrasound imaging in rheumatology. Ann Rheum Dis. 76:1974–1979.Pitre-Champagnat S, Coiffier B, Jourdain L, Benatsou B, Leguerney I, Lassau N (2017) Toward a standardization of ultrasound scanners for dynamic contrast-enhanced ultrasonography: methodology and phantoms. Ultrasound Med Biol. https://doi.org/10.1016/j.ultrasmedbio.2017.06.032Shunichi S, Hiroko I, Fuminori M, Waki H (2009) Definition of contrast enhancement phases of the liver using a perfluoro-based microbubble agent, perflubutane microbubbles. Ultrasound Med Biol 35:1819–1827. doiFairbank WM Jr, Scully MO (1977) A new noninvasive technique for cardiac pressure measurement: resonant scattering of ultrasound from bubbles. IEEE Trans Biomed Eng 24:107–110.Malm S, Frigstad S, Helland F, Oye K, Slordahl S, Skjarpe T (2005) Quantification of resting myocardial blood flow velocity in normal humans using real-time contrast echocardiography. A feasibility study. Cardiovasc Ultrasound 3:16.Arditi M, Frinking PJ, Zhou X, Rognin NG (2006) A new formalism for the quantification of tissue perfusion by the destruction-replenishment method in contrast ultrasound imaging. IEEE Trans Ultrason Ferroelectr Freq Control 53:1118–1129.Savic RM, Jonker DM, Kerbusch T, Karlsson MO (2007) Implementation of a transit compartment model for describing drug absorption in pharmacokinetic studies. J Pharmacokinet Pharmacodyn 34:711–726.Averkiou M, Lampaskis M, Kyriakopoulou K, et al (2010) Quantification of tumor microvascularity with respiratory gated contrast enhanced ultrasound for monitoring therapy. Ultrasound Med Biol 36:68–77.Kuenen MP, Mischi M, Wijkstra H (2011) Contrast-ultrasound diffusion imaging for localization of prostate cancer. IEEE Trans Med Imaging 30:1493–1502.Garcia D, Le Tarnec L, Muth S, Montagnon E, Porée J, Cloutier G(2013) Stolt’s f-k migration for plane wave ultrasound imaging. IEEE Trans Ultrason Ferroelectr Freq Control 60:1853–1867.Brands J, Vink H, Van Teeffelen JW (2011) Comparison of four mathematical models to analyze indicator-dilution curves in the coronary circulation. Med Biol Eng Comput 49:1471–1479.Zhou JH, Cao LH, Zheng W, Liu M, Han F, Li AH (2011) Contrast-enhanced gray-scale ultrasound for quantitative evaluation of tumor response to chemotherapy: preliminary results with a mouse hepatoma model. AJR Am J Roentgenol 196:W13-17.Wei K, Jayaweera AR, Firoozan S, Linka A, Skyba DM, Kaul S (1998) Quantification of myocardial blood flow with ultrasoundinduced destruction of microbubbles administered as a constant venous infusion. Circulation 97:473–483Riascos P, Velasco-Medina J (2005) Efectos Biológicos y Consideraciones de Seguridad en Ultrasonido. Available via https://www.yumpu.com/es/document/view/15350629/efectos-biologicos-y-consideraciones-de-seguridad-en-ultrasonidode Jong N, ten Cate FJ, Vletter WB, Roelandt JR (1993) Quantification of transpulmonary echocontrast effects. Ultrasound Med Biol 19:279–288Quaia E (2011) Assessment of tissue perfusion by contrast-enhanced ultrasound. Eur Radiol 21:604–615

A cloud infrastructure for scalable computing on population imaging databanks

This article describes the software architecture designed to cope with the computing demand of research usage of complex data from the imaging biobank of the Regional Ministry of Health in the Valencia Region (CS). It proposes the use of self-configured virtual clusters on top of on-premise and public cloud infrastructures. It uses a model based on recipes and autoconfiguration to deploy virtual elastic clusters that adjust themselves to the actual workload of the study, therefore reducing operating costs and preventing the need of up-front investments both at the level of the imaging biobank or the final user. All the software used is released under open-source licenses.Blanquer Espert, I.; Caballer Fernández, M.; Martí-Bonmatí, L.; Alberich Bayarri, A.; De La Iglesia Vayá, MDLD.; Martínez, J. (2015). A cloud infrastructure for scalable computing on population imaging databanks. International Journal of Image Mining. 1(2/3):175-187. doi:10.1504/IJIM.2015.073015S17518712/

Randomized pilot study and qualitative evaluation of a clinical decision support system for brain tumour diagnosis based on SV 1H MRS: Evaluation as an additional information procedure for novice radiologists

The results of a randomized pilot study and qualitative evaluation of the clinical decision support system Curiam BT are reported. We evaluated the system's feasibility and potential value as a radiological information procedure complementary to magnetic resonance (MR) imaging to assist novice radiologists in diagnosing brain tumours using MR spectroscopy (1.5 and 3.0T). Fifty-five cases were analysed at three hospitals according to four non-exclusive diagnostic questions. Our results show that Curiam BT improved the diagnostic accuracy in all the four questions. Additionally, we discuss the findings of the users' feedback about the system, and the further work to optimize it for real environments and to conduct a large clinical trial. & 2013 Elsevier Ltd. All rights reserved.This work has been supported by the Spanish Ministry of Science and Innovation - Institut de Salud Carlos III - FIS Contract PI09/90177; and Universitat Politecnica de Valencia - INNOVA UPV 2008 2 1834. We specially thank Miguel Angel Edo, Maria Vano, Carmen Barber, Ana Catala-Gregori, Enrique Molla and Cecilio Poyatos, for their collaboration in the development of this study.Sáez Silvestre, C.; Martí-Bonmatí, L.; Alberich Bayarri, Á.; Robles Viejo, M.; García Gómez, JM. (2014). Randomized pilot study and qualitative evaluation of a clinical decision support system for brain tumour diagnosis based on SV 1H MRS: Evaluation as an additional information procedure for novice radiologists. Computers in Biology and Medicine. 45:26-33. https://doi.org/10.1016/j.compbiomed.2013.11.009S26334

Noninvasive monitoring of serial changes in pulmonary vascular resistance and acute vasodilator testing using cardiac magnetic resonance

Objectives The study sought to evaluate the ability of cardiac magnetic resonance (CMR) to monitor acute and long-term changes in pulmonary vascular resistance (PVR) noninvasively. Background PVR monitoring during the follow-up of patients with pulmonary hypertension (PH) and the response to vasodilator testing require invasive right heart catheterization. Methods An experimental study in pigs was designed to evaluate the ability of CMR to monitor: 1) an acute increase in PVR generated by acute pulmonary embolization (n = 10); 2) serial changes in PVR in chronic PH (n = 22); and 3) changes in PVR during vasodilator testing in chronic PH (n = 10). CMR studies were performed with simultaneous hemodynamic assessment using a CMR-compatible Swan-Ganz catheter. Average flow velocity in the main pulmonary artery (PA) was quantified with phase contrast imaging. Pearson correlation and mixed model analysis were used to correlate changes in PVR with changes in CMR-quantified PA velocity. Additionally, PVR was estimated from CMR data (PA velocity and right ventricular ejection fraction) using a formula previously validated. Results Changes in PA velocity strongly and inversely correlated with acute increases in PVR induced by pulmonary embolization (r = –0.92), serial PVR fluctuations in chronic PH (r = –0.89), and acute reductions during vasodilator testing (r = –0.89, p ≤ 0.01 for all). CMR-estimated PVR showed adequate agreement with invasive PVR (mean bias –1.1 Wood units,; 95% confidence interval: –5.9 to 3.7) and changes in both indices correlated strongly (r = 0.86, p < 0.01). Conclusions CMR allows for noninvasive monitoring of acute and chronic changes in PVR in PH. This capability may be valuable in the evaluation and follow-up of patients with PH

Pancreatic steatosis and iron overload increases cardiovascular risk in non-alcoholic fatty liver disease

ObjectiveTo assess the prevalence of pancreatic steatosis and iron overload in non-alcoholic fatty liver disease (NAFLD) and their correlation with liver histology severity and the risk of cardiometabolic diseases.MethodA prospective, multicenter study including NAFLD patients with biopsy and paired Magnetic Resonance Imaging (MRI) was performed. Liver biopsies were evaluated according to NASH Clinical Research Network, hepatic iron storages were scored, and digital pathology quantified the tissue proportionate areas of fat and iron. MRI-biomarkers of fat fraction (PDFF) and iron accumulation (R2*) were obtained from the liver and pancreas. Different metabolic traits were evaluated, cardiovascular disease (CVD) risk was estimated with the atherosclerotic CVD score, and the severity of iron metabolism alteration was determined by grading metabolic hiperferritinemia (MHF). Associations between CVD, histology and MRI were investigated.ResultsIn total, 324 patients were included. MRI-determined pancreatic iron overload and moderate-to severe steatosis were present in 45% and 25%, respectively. Liver and pancreatic MRI-biomarkers showed a weak correlation (r=0.32 for PDFF, r=0.17 for R2*). Pancreatic PDFF increased with hepatic histologic steatosis grades and NASH diagnosis (p&lt;0.001). Prevalence of pancreatic steatosis and iron overload increased with the number of metabolic traits (p&lt;0.001). Liver R2* significantly correlated with MHF (AUC=0.77 [0.72-0.82]). MRI-determined pancreatic steatosis (OR=3.15 [1.63-6.09]), and iron overload (OR=2.39 [1.32-4.37]) were independently associated with high-risk CVD. Histologic diagnosis of NASH and advanced fibrosis were also associated with high-risk CVD.ConclusionPancreatic steatosis and iron overload could be of utility in clinical decision-making and prognostication of NAFLD

Semi-automated Knee Joint Segmentation from Magnetic Resonance Images based on a Subchondral Bone Approach

Abstract: The aim of this paper is to present the development of a semi-automatic segmentation method for human knee cartilage and bones from magnetic resonance images (MRI). This segmentation process belongs to a higher aim that consists of a 3D simulation of knee joint to find how stresses are distributed in contact regions between cartilages and to quantify them as well as the contact region size. Imaging acquisition was performed in a 3T scanner with high spatial resolution (voxel size 0.293 x 0.293 x 1 mm). This method consists of a 2D segmentation of each sagittal plane and a reconstruction of the volumetric image with the segmented masks

The Brain Resting-State Functional Connectivity Underlying Violence Proneness: Is It a Reliable Marker for Neurocriminology? A Systematic Review

Introduction: There is growing scientific interest in understanding the biological mechanisms affecting and/or underlying violent behaviors in order to develop effective treatment and prevention programs. In recent years, neuroscientific research has tried to demonstrate whether the intrinsic activity within the brain at rest in the absence of any external stimulation (resting-state functional connectivity; RSFC) could be employed as a reliable marker for several cognitive abilities and personality traits that are important in behavior regulation, particularly, proneness to violence. Aims: This review aims to highlight the association between the RSFC among specific brain structures and the predisposition to experiencing anger and/or responding to stressful and distressing situations with anger in several populations. Methods: The scientific literature was reviewed following the PRISMA quality criteria for reviews, using the following digital databases: PubMed, PsycINFO, Psicodoc, and Dialnet. Results: The identification of 181 abstracts and retrieval of 34 full texts led to the inclusion of 17 papers. The results described in our study offer a better understanding of the brain networks that might explain the tendency to experience anger. The majority of the studies highlighted that diminished RSFC between the prefrontal cortex and the amygdala might make people prone to reactive violence, but that it is also necessary to contemplate additional cortical (i.e. insula, gyrus [angular, supramarginal, temporal, fusiform, superior, and middle frontal], anterior and posterior cingulated cortex) and subcortical brain structures (i.e. hippocampus, cerebellum, ventral striatum, and nucleus centralis superior) in order to explain a phenomenon as complex as violence. Moreover, we also described the neural pathways that might underlie proactive violence and feelings of revenge, highlighting the RSFC between the OFC, ventral striatal, angular gyrus, mid-occipital cortex, and cerebellum. Conclusions. The results from this synthesis and critical analysis of RSFC findings in several populations offer guidelines for future research and for developing a more accurate model of proneness to violence, in order to create effective treatment and prevention programs

Medical Imaging Processing Architecture on ATMOSPHERE Federated Platform

[EN] This paper describes the development of applications in the frame of the ATMOSPHERE platform. ATMOSPHERE provides means for developing container-based applications over a federated cloud offering measurin he trustworthiness of the applications. In this paper we show the design of a transcontinental application in the frame of medical imaging that keeps the data at one end and uses the processing capabilities of the resources available at the other end. The applications are described using TOSCA blueprints and the federation of IaaS resources is performed by the Fogbow middleware. Privacy guarantees are provided by means of SCONE and intensive computing resources are integrated through the use of GPUs directly mounted on the containers.The work in this article has been co-funded by project ATMOSPHERE, funded jointly by the European Commission under the Cooperation Programme, Horizon 2020 grant agreement No 777154 and the Brazilian Ministerio de Ci ¿ encia, Tecnologia e ¿ Inovac¿ao (MCTI), number 51119. ¿ The authors also want to acknowledge the research grant from the regional government of the Comunitat Valenciana (Spain), co-funded by the European Union ERDF funds (European Regional Development Fund) of the Comunitat Valenciana 2014- 2020, with reference IDIFEDER/2018/032 (HighPerformance Algorithms for the Modelling, Simulation and early Detection of diseases in Personalized Medicine).Blanquer Espert, I.; Alberich-Bayarri, Á.; García-Castro, F.; Teodoro, G.; Meirelles, A.; Nascimento, B.; Meira Jr., W.... (2019). Medical Imaging Processing Architecture on ATMOSPHERE Federated Platform. ScitePress. 589-594. http://hdl.handle.net/10251/181077S58959

Intravoxel Incoherent Motion Metrics as Potential Biomarkers for Survival in Glioblastoma

Intravoxel incoherent motion (IVIM) is an MRI technique with potential applications in measuring brain tumor perfusion, but its clinical impact remains to be determined. We assessed the usefulness of IVIM-metrics in predicting survival in newly diagnosed glioblastoma. Methods Fifteen patients with glioblastoma underwent MRI including spin-echo echo-planar DWI using 13 b-values ranging from 0 to 1000 s/mm2. Parametric maps for diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were generated for contrast-enhancing regions (CER) and non-enhancing regions (NCER). Regions of interest were manually drawn in regions of maximum f and on the corresponding dynamic susceptibility contrast images. Prognostic factors were evaluated by Kaplan-Meier survival and Cox proportional hazards analyses. Results We found that fCER and D*CER correlated with rCBFCER. The best cutoffs for 6-month survival were fCER>9.86% and D*CER>21.712 x10−3mm2/s (100% sensitivity, 71.4% specificity, 100% and 80% positive predictive values, and 80% and 100% negative predictive values; AUC:0.893 and 0.857, respectively). Treatment yielded the highest hazard ratio (5.484; 95% CI: 1.162–25.88; AUC: 0.723; P = 0.031); fCER combined with treatment predicted survival with 100% accuracy. Conclusions The IVIM-metrics fCER and D*CER are promising biomarkers of 6-month survival in newly diagnosed glioblastom