Nuevos tiempos para la neuroimagen de Medicina Nuclear en España: ¿de dónde partimos? / A new era for Nuclear Medicine neuroimaging in Spain: Where do we start from in Spain?

Objetivo. conocer la situación de los estudios de neuroimagen de Medicina Nuclear que se realizaron en España en el año 2013 y primer trimestre del 2014, con el fin de definir las actividades del grupo de trabajo de Neuroimagen de la Sociedad Española de Medicina Nuclear e Imagen Molecular (SEMNIM). Material y métodos. Se diseñó un cuestionario de 14 preguntas dividido en 3 partes: características de los servicios (equipamiento y profesionales involucrados), tipo de exploraciones e indicaciones clínicas y métodos de evaluación. El cuestionario se remitió a los 166 servicios de Medicina Nuclear que figuraban en la secretaría de la Sociedad Española de Medicina Nuclear e Imagen Molecular. Resultados. Respondieron a la encuesta un total de 54 centros distribuidos entre todas las comunidades autónomas. La mayoría de los centros realizaron entre 300 y 800 exploraciones de neuroimagen al año, representando más de 25 exploraciones al mes. La media de equipos por servicio era de 3, teniendo la mitad de ellos equipos PET/TC y SPECT/TC. Las exploraciones realizadas con más frecuencia son la SPECT cerebral con 123I-FP-CIT, seguida de la SPECT cerebral de perfusión y de la PET con 18F-FDG, siendo las indicaciones clínicas más frecuentes los estudios de deterioro cognitivo seguidos por los de trastornos del movimiento. Para la evaluación de las pruebas la mayoría de los centros utilizaron únicamente la valoración visual, en la valoración cuantitativa la cuantificación por regiones de interés fue la más utilizada. Conclusiones. Los resultados reflejan cuál fue la actividad clínica del año 2013 y primer trimestre del 2014, siendo las indicaciones principales los estudios de deterioro cognitivo y trastorno del movimiento. La variabilidad en la evaluación de los estudios PET y la colaboración con los especialistas clínicos que demandan las exploraciones de neuroimagen de Medicina Nuclear son algunos de los retos que debemos afrontar en los próximos años (AU)

Objective. To determine the status of neuroimaging studies of Nuclear Medicine in Spain during 2013 and first quarter of 2014, in order to define the activities of the neuroimaging group of the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM). Material and methods. A questionnaire of 14 questions was designed, divided into 3 parts: characteristics of the departments (equipment and professionals involved); type of scans and clinical indications; and evaluation methods. The questionnaire was sent to 166 Nuclear Medicine departments. Results. A total of 54 departments distributed among all regions completed the questionnaire. Most departments performed between 300 and 800 neuroimaging examinations per year, representing more than 25 scans per month. The average pieces of equipment were three; half of the departments had a PET/CT scanner and SPECT/CT equipment. Scans performed more frequently were brain SPECT with 123I-FP-CIT, followed by brain perfusion SPECT and PET with 18F-FDG. The most frequent clinical indications were cognitive impairment followed by movement disorders. For evaluation of the images most sites used only visual assessment, and for the quantitative assessment the most used was quantification by region of interest. Conclusions. These results reflect the clinical activity of 2013 and first quarter of 2014. The main indications of the studies were cognitive impairment and movement disorders. Variability in the evaluation of the studies is among the challenges that will be faced in the coming years (AU)

Biomarcadores por tomografia por emisión de positrones (PET): imagen de la patología de Alzheimer y la neurodegeneración al servicio del diagnóstico clínico / PET biomarkers: Use of imaging techniques in Alzheimer disease and neurodegeneration clinical diagnosis

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A new era for Nuclear Medicine neuroimaging in Spain: Where do we start from in Spain? / Nuevos tiempos para la neuroimagen de Medicina Nuclear en España: ¿de dónde partimos?

OBJECTIVE: To determine the status of neuroimaging studies of Nuclear Medicine in Spain during 2013 and first quarter of 2014, in order to define the activities of the neuroimaging group of the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM). MATERIAL AND METHODS: A questionnaire of 14 questions was designed, divided into 3 parts: characteristics of the departments (equipment and professionals involved); type of scans and clinical indications; and evaluation methods. The questionnaire was sent to 166 Nuclear Medicine departments. RESULTS: A total of 54 departments distributed among all regions completed the questionnaire. Most departments performed between 300 and 800 neuroimaging examinations per year, representing more than 25 scans per month. The average pieces of equipment were three; half of the departments had a PET/CT scanner and SPECT/CT equipment. Scans performed more frequently were brain SPECT with 123I-FP-CIT, followed by brain perfusion SPECT and PET with 18F-FDG. The most frequent clinical indications were cognitive impairment followed by movement disorders. For evaluation of the images most sites used only visual assessment, and for the quantitative assessment the most used was quantification by region of interest. CONCLUSIONS: These results reflect the clinical activity of 2013 and first quarter of 2014. The main indications of the studies were cognitive impairment and movement disorders. Variability in the evaluation of the studies is among the challenges that will be faced in the coming years.

Recomendaciones para la utilización de biomarcadores de imagen PET en el proceso diagnóstico de las enfermedades neurodegenerativas que cursan con demencia: documento de consenso SEMNIM y SEN / Recommendations for the use of PET imaging biomarkers in the diagnosis of neurodegenerative conditions associated with dementia: SEMNIM and SEN consensus

Los nuevos criterios diagnósticos para la enfermedad de Alzheimer (EA) reconocen el interés de los biomarcadores, tanto para mejorar la especificidad en sujetos en fase de demencia, como para facilitar el diagnóstico precoz del proceso fisiopatológico de la EA en personas en fases prodrómicas. La disponibilidad actual de biomarcadores de imagen PET de disfunción neuronal (PET-FDG) y de depósito de proteína beta amiloide (PET-Amiloide), ofrecen a los especialistas clínicos involucrados en la evaluación de pacientes con deterioro cognitivo la oportunidad de aplicar los nuevos criterios en su práctica clínica. Sin embargo, resulta imprescindible que las sociedades científicas implicadas en la utilización de las nuevas herramientas de apoyo al diagnóstico clínico se pongan de acuerdo en cuales deben de ser las recomendaciones para su utilización clínica. En este trabajo se lleva a cabo una revisión sistemática de la literatura sobre el uso de PET-amiloide y PET-FDG, tanto en el proceso diagnóstico de la EA como de otras enfermedades neurodegenerativas que cursan con demencia. Asimismo, se proponen una serie de recomendaciones consensuadas por la Sociedad Española de Medicina Nuclear y la Sociedad Española de Neurología a modo guía para la utilización adecuada de los biomarcadores de imagen PET (AU)

The new diagnostic criteria for Alzheimer's disease (AD) acknowledges the interest given to biomarkers to improve the specificity in subjects with dementia and to facilitate an early diagnosis of the pathophysiological process of AD in the prodromal or pre-dementia stage. The current availability of PET imaging biomarkers of synaptic dysfunction (PET-FDG) and beta amyloid deposition using amyloid-PET provides clinicians with the opportunity to apply the new criteria and improve diagnostic accuracy in their clinical practice. Therefore, it seems essential for the scientific societies involved to use the new clinical diagnostic support tools to establish clear, evidence-based and agreed set of recommendations for their appropriate use. The present work includes a systematic review of the literature on the utility of FDG-PET and amyloid-PET for the diagnosis of AD and related neurodegenerative diseases that occur with dementia. Thus, we propose a series of recommendations agreed on by the Spanish Society of Nuclear Medicine and Spanish Society of Neurology as a consensus statement on the appropriate use of PET imaging biomarkers (AU)

Neuroimagen funcional en el diagnóstico de pacientes con síndrome parkinsoniano: actualización y recomendaciones para el uso clínico / Functional neuroimaging in the diagnosis of patients with Parkinsonism: Update and recommendations for clinical use

Las técnicas de neuroimagen funcional se han utilizado tradicionalmente en la investigación de los pacientes que presentan un síndrome parkinsoniano. Sin embargo, la aparición de radiofármacos comerciales junto a la disponibilidad de equipos de tomografía por emisión de fotón único (SPECT) y más recientemente de la tomografía por emisión de positrones (PET), han permitido su empleo rutinario en la práctica clínica. Precisamente el desarrollo y grado de evidencia clínica alcanzado por los biomarcadores de neuroimagen durante las 2 últimas décadas ha conllevado que progresivamente se estén incluyendo en los criterios clínicos de diagnóstico de enfermedades neurodegenerativas que cursan con un síndrome parkinsoniano. No obstante, la diversidad de radiofármacos que permiten evaluar la funcionalidad de las vías anatómicas involucradas en la neurodegeneración presente en los diferentes síndromes parkinsonianos (vía nigroestriatal dopaminérgica, actividad neuronal de los ganglios basales y la corteza, inervación simpática miocárdica), junto a las técnicas de neuroimagen (gammagrafía, SPECT y PET) han originado cierta controversia con respecto a la indicación de las pruebas de neuroimagen como exploración complementaria. En esta revisión realizada por un panel de expertos en medicina nuclear y neurología se analizan las técnicas de neuroimagen funcional disponibles haciendo especial énfasis en las consideraciones prácticas del diagnóstico de pacientes con un síndrome parkinsoniano de origen incierto y la valoración de la progresión de la enfermedad de Parkinson (AU)

Functional Neuroimaging has been traditionally used in research for patients with different Parkinsonian syndromes. However, the emergence of commercial radiotracers together with the availability of single photon emission computed tomography (SPECT) and, more recently, positron emission tomography (PET) have made them available for clinical practice. Particularly, the development of clinical evidence achieved by functional neuroimaging techniques over the past two decades have motivated a progressive inclusion of several biomarkers in the clinical diagnostic criteria for neurodegenerative diseases that occur with Parkinsonism. However, the wide range of radiotracers designed to assess the involvement of different pathways in the neurodegenerative process underlying Parkinsonian syndromes (dopaminergic nigrostriatal pathway integrity, basal ganglia and cortical neuronal activity, myocardial sympathetic innervation), and the different neuroimaging techniques currently available (scintigraphy, SPECT and PET), have generated some controversy concerning the best neuroimaging test that should be indicated for the differential diagnosis of Parkinsonism. In this article, a panel of nuclear medicine and neurology experts has evaluated the functional neuroimaging techniques emphazising practical considerations related to the diagnosis of patients with uncertain origin parkinsonism and the assessment Parkinson’s disease progression (AU)

[Functional neuroimaging in the diagnosis of patients with Parkinsonism: Update and recommendations for clinical use]. / Neuroimagen funcional en el diagnóstico de pacientes con síndrome parkinsoniano: actualización y recomendaciones para el uso clínico.

Functional Neuroimaging has been traditionally used in research for patients with different Parkinsonian syndromes. However, the emergence of commercial radiotracers together with the availability of single photon emission computed tomography (SPECT) and, more recently, positron emission tomography (PET) have made them available for clinical practice. Particularly, the development of clinical evidence achieved by functional neuroimaging techniques over the past two decades have motivated a progressive inclusion of several biomarkers in the clinical diagnostic criteria for neurodegenerative diseases that occur with Parkinsonism. However, the wide range of radiotracers designed to assess the involvement of different pathways in the neurodegenerative process underlying Parkinsonian syndromes (dopaminergic nigrostriatal pathway integrity, basal ganglia and cortical neuronal activity, myocardial sympathetic innervation), and the different neuroimaging techniques currently available (scintigraphy, SPECT and PET), have generated some controversy concerning the best neuroimaging test that should be indicated for the differential diagnosis of Parkinsonism. In this article, a panel of nuclear medicine and neurology experts has evaluated the functional neuroimaging techniques emphazising practical considerations related to the diagnosis of patients with uncertain origin parkinsonism and the assessment Parkinson's disease progression.

Validación de técnicas de segmentación para la tomografía por emisión de positrones mediante imágenes ex-vivo de piezas quirúrgicas oncológicas / Validation of segmentation techniques for positron emission tomography using ex-vivo images of oncological surgical specimens

Objetivo: Diseñar una técnica novedosa de adquisición ex-vivo para establecer un marco común de validación de diferentes técnicas de segmentación para imágenes PET oncológicas. Evaluar sobre estas imágenes el funcionamiento de varios algoritmos de segmentación automática. Material y métodos: En 15 pacientes oncológicos se realizaron estudios PET ex-vivo de las piezas quirúrgicas extraídas durante la cirugía, previa inyección de 18F-FDG, adquiriéndose imágenes en 2 tomógrafos: un PET/CT clínico y un tomógrafo PET de alta resolución. Se determinó el volumen tumoral real en cada paciente, generándose una imagen de referencia para la segmentación de cada tumor. Las imágenes se segmentaron con 12 algoritmos automáticos y con un método estándar para PET (umbral relativo del 42%) y se evaluaron los resultados mediante parámetros cuantitativos. Resultados: La segmentación de imágenes PET de piezas quirúrgicas ha demostrado que para imágenes PET de alta resolución 8 de las 12 técnicas de segmentación evaluadas superan al método estándar del 42%. Sin embargo, ninguno de los algoritmos superó al método estándar en las imágenes procedentes del PET/CT clínico. Debido al gran interés de este conjunto de imágenes PET, todos los estudios se han publicado a través de Internet con el fin de servir de marco común de validación y comparación de diferentes técnicas de segmentación. Conclusiones: Se ha propuesto una técnica novedosa para validar técnicas de segmentación para imágenes PET oncológicas, adquiriéndose estudios ex-vivo de piezas quirúrgicas. Se ha demostrado la utilidad de este conjunto de imágenes PET mediante la evaluación de varios algoritmos automáticos (AU)

Objective: To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images. Material and methods: In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed during surgery were performed after injection of 18F-FDG. Images were acquired in two scanners: a clinical PET/CT and a high-resolution PET scanner. Real tumor volume was determined in each patient, and a reference image was generated for segmentation of each tumor. Images were segmented with 12 automatic algorithms and with a standard method for PET (relative threshold at 42%) and results were evaluated by quantitative parameters. Results: It has been possible to demonstrate by segmentation of PET images of surgical specimens that on high resolution PET images, 8 out of 12 evaluated segmentation techniques outperformed the standard method, whose value is 42%. However, none of the algorithms outperformed the standard method when applied on images from the clinical PET/CT. Due to the great interest of this set of PET images, all studies have been published on the Internet in order to provide a common framework for validation and comparison of different segmentation techniques. Conclusions: We have proposed a novel technique to validate segmentation techniques for oncological PET images, acquiring ex-vivo PET studies of surgical specimens. We have demonstrated the usefulness of this set of PET images by evaluating several automatic segmentation algorithms (AU)

[Validation of segmentation techniques for positron emission tomography using ex-vivo images of oncological surgical specimens]. / Validación de técnicas de segmentación para la tomografía por emisión de positrones mediante imágenes ex-vivo de piezas quirúrgicas oncológicas.

OBJECTIVE: To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images. MATERIAL AND METHODS: In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed during surgery were performed after injection of (18)F-FDG. Images were acquired in two scanners: a clinical PET/CT and a high-resolution PET scanner. Real tumor volume was determined in each patient, and a reference image was generated for segmentation of each tumor. Images were segmented with 12 automatic algorithms and with a standard method for PET (relative threshold at 42%) and results were evaluated by quantitative parameters. RESULTS: It has been possible to demonstrate by segmentation of PET images of surgical specimens that on high resolution PET images, 8 out of 12 evaluated segmentation techniques outperformed the standard method, whose value is 42%. However, none of the algorithms outperformed the standard method when applied on images from the clinical PET/CT. Due to the great interest of this set of PET images, all studies have been published on the Internet in order to provide a common framework for validation and comparison of different segmentation techniques. CONCLUSIONS: We have proposed a novel technique to validate segmentation techniques for oncological PET images, acquiring ex-vivo PET studies of surgical specimens. We have demonstrated the usefulness of this set of PET images by evaluating several automatic segmentation algorithms.

Evaluation of spatial resolution of a PET scanner through the simulation and experimental measurement of the recovery coefficient.

PURPOSE: In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured radioactivity concentration for small structures. METHODS: In a PET image, the recovery factors of radioactive spheres were measured and their comparison with simulated recovery coefficients yielded the tomographic spatial resolution. Following this methodology, resolution was determined in different surrounding media and several conditions for reconstruction, including clinical conditions for brain PET studies. All spatial resolution values were compared with those obtained using classical methods with point and line sources. RESULTS: In each considered condition, spatial resolution of the PET image estimated using the recovery coefficient showed good agreement with classical methods measurements, validating the procedure. CONCLUSION: Measurement of the recovery coefficient provides an assessment of tomographic spatial resolution, particularly in clinical studies conditions.