El dilema clínico frente a los pacientes con ergometría positiva y prueba de perfusión miocárdica con SPECT normal / The clinical dilemma facing patients with positive stress test and normal SPECT myocardial perfusion imaging

La evaluación de la perfusión miocárdica con SPECT combina una prueba de esfuerzo (ergometría o estrés farmacológico) junto a imágenes de perfusión con radioisótopos. Este estudio es útil para establecer el diagnóstico de enfermedad arterial coronaria, estratificar el riesgo de infarto y tomar decisiones terapéuticas. Un resultado normal aporta un alto valor predictivo negativo, es decir, una muy baja probabilidad de que el paciente presente eventos cardiovasculares. El hallazgo de signos de isquemia en la ergometría podría poner en jaque el valor predictivo negativo de una perfusión normal. En presencia de este resultado, el paso siguiente es evaluar los predictores de riesgo en la ergometría, el riesgo propio del paciente en función de los antecedentes clínicos y el puntaje cálcico coronario, cuando este se encuentra disponible. Ante la presencia concomitante de otros marcadores de riesgo se sugiere completar la evaluación con un estudio anatómico.El uso de nuevas tecnologías podría mejorar la precisión en la predicción de eventos. (AU)

Assessment of myocardial perfusion with SPECT combines a stress test (ergometry or pharmacological stress) with radioisotope perfusion imaging. This test is helpful to diagnose coronary artery disease, stratify the risk of heart attack, and make therapeutic decisions. A normal result provides a high negative predictive value; therefore, the probability of cardiovascular events is very low. Signs of ischemia on an ergometry could jeopardize the negative predictive value of normal perfusion. In this clinical setting, the next step is to evaluate the risk predictors in the stress test, the individual risk based on the clinical history, and the coronary calcium score when available. Given the simultaneous presence of other risk markers,completing the evaluation with an anatomical study is suggested. The use of new technologies could improve the accuracy of event prediction. (AU)

Crossed aphasia in a left-handed patient with non-fluent variant of primary progressive aphasia with left asymmetric brain SPECT.

Primary progressive aphasia is a clinical syndrome caused by neurodegeneration of areas and neural networks involved in language, usually in the left hemisphere. The term "crossed aphasia" denotes an acquired language dysfunction caused by a lesion in the ipsilateral hemisphere to the dominant hand. Objective: To describe a case of crossed aphasia in a 60-year-old left-handed patient with a non-fluent variant of primary progressive aphasia diagnosis (age of onset=52), evidenced by a left asymmetry on brain SPECT scan. Methods: Clinical and family history, the Edinburgh Handedness Inventory, Measurement of Functional Activities in Older Adults in the Community, the "Mini-Mental State Examination", the Trail Making Test, the Tower of London, and the Neuropsychological assessment for dementia, and neuroimaging studies were carried out. Results: Neuropsychological assessment showed severe cognitive impairment, especially regarding language. The magnetic resonance imaging showed important signs of cortico-subcortical atrophy, with predominance in the frontal and temporal lobes. The single-photon emission computed tomography scan showed moderate to severe hypoperfusion in the left cerebral hemisphere, including the hippocampus. Conclusion: We described a clinical case of crossed aphasia in a left-handed woman with a non-fluent variant of primary progressive aphasia with asymmetry on brain SPECT, mainly on the left, followed up for seven years.

A afasia progressiva primária é uma síndrome clínica causada por uma neurodegeneração de áreas e redes neurais envolvidas na linguagem, geralmente no hemisfério esquerdo. O termo "afasia cruzada" denota uma disfunção adquirida de linguagem causada por uma lesão no hemisfério ipsilateral da mão dominante. Objetivo: Relatamos um caso de afasia cruzada em uma paciente de 60 anos, canhota, com um quadro clínico de afasia progressiva primária variante não fluente (idade de início=52), evidenciada por assimetria no SPECT cerebral à esquerda. Métodos: Foram realizados para o diagnóstico do caso: história clínica e familiar, o Inventário de Dominância de Edinburgh, a Escala de Atividades Funcionais de Pfeffer, o Miniexame do Estado Mental, o Teste das Trilhas, o Teste da Torre de Londres, a Avaliação Neuropsicológica Adequada às Demências e exames de neuroimagem. Resultados: A avaliação neuropsicológica mostrou comprometimento cognitivo severo, principalmente sobre a linguagem; a ressonância magnética do crânio mostrou sinais de involução córtico-subcortical, com predominância nos lobos frontal e temporal e a cintilografia cerebral por emissão de fóton único mostrou hipoperfusão moderada a severa no hemisfério cerebral esquerdo, incluindo o hipocampo. Conclusão: Registramos um caso clínico de afasia cruzada em uma paciente canhota com afasia progressiva primária variante não fluente com assimetria no SPECT cerebral, principalmente à esquerda, seguida há sete anos.

Crossed aphasia in a left-handed patient with non-fluent variant of primary progressive aphasia with left asymmetric brain SPECT / Afasia cruzada em paciente canhota com afasia progressiva primária variante não fluente com SPECT cerebral assimétrico à esquerda

ABSTRACT Primary progressive aphasia is a clinical syndrome caused by neurodegeneration of areas and neural networks involved in language, usually in the left hemisphere. The term "crossed aphasia" denotes an acquired language dysfunction caused by a lesion in the ipsilateral hemisphere to the dominant hand. Objective: To describe a case of crossed aphasia in a 60-year-old left-handed patient with a non-fluent variant of primary progressive aphasia diagnosis (age of onset=52), evidenced by a left asymmetry on brain SPECT scan. Methods: Clinical and family history, the Edinburgh Handedness Inventory, Measurement of Functional Activities in Older Adults in the Community, the "Mini-Mental State Examination", the Trail Making Test, the Tower of London, and the Neuropsychological assessment for dementia, and neuroimaging studies were carried out. Results: Neuropsychological assessment showed severe cognitive impairment, especially regarding language. The magnetic resonance imaging showed important signs of cortico-subcortical atrophy, with predominance in the frontal and temporal lobes. The single-photon emission computed tomography scan showed moderate to severe hypoperfusion in the left cerebral hemisphere, including the hippocampus. Conclusion: We described a clinical case of crossed aphasia in a left-handed woman with a non-fluent variant of primary progressive aphasia with asymmetry on brain SPECT, mainly on the left, followed up for seven years.

RESUMO A afasia progressiva primária é uma síndrome clínica causada por uma neurodegeneração de áreas e redes neurais envolvidas na linguagem, geralmente no hemisfério esquerdo. O termo "afasia cruzada" denota uma disfunção adquirida de linguagem causada por uma lesão no hemisfério ipsilateral da mão dominante. Objetivo: Relatamos um caso de afasia cruzada em uma paciente de 60 anos, canhota, com um quadro clínico de afasia progressiva primária variante não fluente (idade de início=52), evidenciada por assimetria no SPECT cerebral à esquerda. Métodos: Foram realizados para o diagnóstico do caso: história clínica e familiar, o Inventário de Dominância de Edinburgh, a Escala de Atividades Funcionais de Pfeffer, o Miniexame do Estado Mental, o Teste das Trilhas, o Teste da Torre de Londres, a Avaliação Neuropsicológica Adequada às Demências e exames de neuroimagem. Resultados: A avaliação neuropsicológica mostrou comprometimento cognitivo severo, principalmente sobre a linguagem; a ressonância magnética do crânio mostrou sinais de involução córtico-subcortical, com predominância nos lobos frontal e temporal e a cintilografia cerebral por emissão de fóton único mostrou hipoperfusão moderada a severa no hemisfério cerebral esquerdo, incluindo o hipocampo. Conclusão: Registramos um caso clínico de afasia cruzada em uma paciente canhota com afasia progressiva primária variante não fluente com assimetria no SPECT cerebral, principalmente à esquerda, seguida há sete anos.

Calidad de la imagen de tomografía computarizada versus dosis en estudios híbridos: resultados preliminares en maniquí

RESUMEN Fundamento: los estudios híbridos producen una dosis total de radiación que es resultado de la dosis proveniente del radiofármaco y la emitida por la tomografía computarizada, por eso la optimización es indispensable. Objetivo: evaluar la relación de la dosis de tomografía computarizada con algunos parámetros de calidad de la imagen en protocolos de estudios híbridos. Métodos: para evaluar la calidad de la imagen se emplearon los maniquíes de Catphan y de Livermore en 12 protocolos preestablecidos de un equipo de tomografía por emisión del fotón único Mediso. Los datos de los descriptores de dosis de cada estudio se obtuvieron del cabezal DICOM. Se compararon los parámetros de calidad de imagen clásicos como ruido y la MTF 50 % para el maniquí de Catphan, y otros como la relación contraste ruido, el promedio de números de Hounsfield y su desviación estándar en las regiones de interés de los órganos correspondientes, en el maniquí de Livermore. Se analizó la relación de estos parámetros de calidad con los descriptores de dosis de los diferentes protocolos. Resultados: los parámetros relacionados con la calidad en el maniquí de Catphan no mostraron diferencias significativas (p<0,05) entre los diferentes protocolos para estudios híbridos. Se encontraron diferencias significativas entre los protocolos clínicos con diferentes calidades y el protocolo clínico estándar, para el maniquí antropomórfico, en la desviación estándar de los números de Hounsfield y en la relación contraste ruido (p<0,05). Conclusiones: el estudio de la relación contraste ruido y la desviación de los números de tomografía computarizada en las regiones de interés pueden servir de parámetro cuantitativo para la optimización de dosis en escenario clínico.

ABSTRACT Background: hybrid studies produce a total radiation dose that is the result of the dose imparted by the radiopharmaceutical and that emitted by the computed tomography, therefore optimization is essential. Objective: to evaluate the relationship of the computed tomography dose with some image quality parameters in hybrid study protocols. Methods: to evaluate the image quality, the Catphan and Livermore Phantom were used in 12 pre-established protocols of a Mediso single photon emission tomography equipment. The data for the dose descriptors for each study were obtained from the DICOM head. The classic image quality parameters such as noise and the MTF 50% for the Catphan manikin, and others such as the contrast-noise ratio, the average of Hounsfield numbers and their standard deviation in the regions of interest of the corresponding organs were compared, in Livermore's mannequin. The relationship of these quality parameters with the dose descriptors of the different protocols was analyzed. Results: the quality-related parameters in the Catphan manikin did not show significant differences (p <0.05) between the different protocols for hybrid studies. Significant differences were found between the clinical protocols with different qualities and the standard clinical protocol, for the anthropomorphic manikin, in the standard deviation of the Hounsfield numbers and in the contrast-to-noise ratio (p <0.05). Conclusions: the study of the contrast noise ratio and the deviation of the computed tomography numbers in the regions of interest can serve as a quantitative parameter for the optimization of doses in the clinical setting.

Correlation between 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET in patients with Parkinson's disease: a pilot study.

OBJECTIVE: To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (18F-FDOPA PET) in the setting of a movement disorders clinic. MATERIALS AND METHODS: In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson's disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed. RESULTS: The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when 99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between 18F-FDOPA PET and 99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01). CONCLUSION: It appears that 99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.

OBJETIVO: Determinar se a 99mTc-TRODAT-1 SPECT fornece resultados comparáveis aos da 18F-FDOPA PET, ferramenta menos acessível e menos amplamente disponível, no contexto de uma clínica de distúrbios do movimento. MATERIAIS E MÉTODOS: Neste estudo prospectivo, oito indivíduos com diagnóstico clínico de doença de Parkinson foram selecionados aleatoriamente entre pacientes em tratamento em uma clínica de distúrbios do movimento e submetidos a 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET. Os resultados foram lidos por dois observadores experientes e uma análise semiquantitativa foi realizada. RESULTADOS: As análises visual e semiquantitativa foram concordantes para todos os estudos, mostrando que a captação do radiotraçador no estriado contralateral do lado mais afetado foi menor quando a 99mTc-TRODAT-1 SPECT foi empregada. A análise semiquantitativa demonstrou uma correlação significativa entre 18F-FDOPA PET e 99mTc-TRODAT-1 SPECT (r = 0,73; p < 0,01). CONCLUSÃO: A 99mTc-TRODAT-1 SPECT parece ser uma opção válida para o estudo da função dopaminérgica em um ambiente clínico.

Correlation between 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET in patients with Parkinson's disease: a pilot study / Correlação entre 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET em pacientes com doença de Parkinson: um estudo piloto

Abstract Objective: To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (18F-FDOPA PET) in the setting of a movement disorders clinic. Materials and Methods: In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson's disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed. Results: The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when 99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between 18F-FDOPA PET and 99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01). Conclusion: It appears that 99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.

Resumo Objetivo: Determinar se a 99mTc-TRODAT-1 SPECT fornece resultados comparáveis aos da 18F-FDOPA PET, ferramenta menos acessível e menos amplamente disponível, no contexto de uma clínica de distúrbios do movimento. Materiais e Métodos: Neste estudo prospectivo, oito indivíduos com diagnóstico clínico de doença de Parkinson foram selecionados aleatoriamente entre pacientes em tratamento em uma clínica de distúrbios do movimento e submetidos a 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET. Os resultados foram lidos por dois observadores experientes e uma análise semiquantitativa foi realizada. Resultados: As análises visual e semiquantitativa foram concordantes para todos os estudos, mostrando que a captação do radiotraçador no estriado contralateral do lado mais afetado foi menor quando a 99mTc-TRODAT-1 SPECT foi empregada. A análise semiquantitativa demonstrou uma correlação significativa entre 18F-FDOPA PET e 99mTc-TRODAT-1 SPECT (r = 0,73; p < 0,01). Conclusão: A 99mTc-TRODAT-1 SPECT parece ser uma opção válida para o estudo da função dopaminérgica em um ambiente clínico.

Does Tight Glucose Control During the First 24 hours of Hospitalization Reduce Scintigraphic Infarct Size in STEMI Patients?

Abstract Background Hyperglycemia at the time of admission is related to increased mortality and poor prognosis in patients diagnosed with ST-segment elevation myocardial infarction (STEMI). Objective We aimed to investigate whether tight glucose control during the first 24 hours of STEMI decreases the scintigraphic infarct size. Methods The study population consisted of 56 out of 134 consecutive patients hospitalized with STEMI in a coronary care unit. Twenty-eight patients were treated with continuous insulin infusion during the first 24 hours of hospitalization, while the other 28 patients were treated with subcutaneous insulin on an as-needed basis. The final infarct size was evaluated with single-photon emission computed tomography (SPECT) in all patients on days 4 to 10 of hospitalization. The groups were compared and then predictors of final infarct size were analyzed with univariate and multivariate linear regression analysis. A p-value < 0.05 was considered statistically significant. Results The mean glucose level in the first 24 hours was 130 ± 20 mg/dL in the infusion group and 152 ± 31 mg/dL in the standard care group (p = 0.002), while the mean final infarct size was 20 ± 12% and 27 ± 15% (p = 0.06), respectively. The multivariate linear regression analysis demonstrated that the mean 24-hour glucose level was an independent predictor of the final infarct size (beta 0.29, p = 0.026). Conclusion Tight glucose control with continuous insulin infusion was not associated with smaller infarct size when compared to standard care in STEMI patients. (Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0)

Neumoconiosis / Pneumoconiosis

RESUMEN La neumoconiosis es una enfermedad, con características radiológicas similares a la silicosis, que afecta a los trabajadores dedicados al trasporte de carbón que se exponen durante los procesos de extracción y depósito de polvo de carbón en las centrales térmicas, la industria siderúrgica, la industria química e incluso en la venta y uso de equipos electrodomésticos. Se presenta un paciente de 65 años, con antecedentes de reiterados ingresos por neumonía extra hospitalaria, que presentaba falta de aire después de realizar cualquier esfuerzo físico. La tomografía de tórax confirmó que el paciente había sufrido una exposición prolongada al humo del carbón. Se diagnosticó la presencia de un fibroenfisema bulloso y adenopatías mediastinales. La prevención es la medida más eficaz para la lucha contra esta enfermedad. Se debe implementar el estricto cumplimiento de las medidas técnicas y la vigilancia constante de los niveles de polvo permitidos.

ABSTRACT Pneumoconiosis is a disease, with radiological characteristics similar to silicosis, which affects coal workers during coal dust deposition and extraction in thermal power plants, steel and chemical industry, and even in the sale and use of household appliances. We present a 65-year-old patient with a history of recurrent admissions for community-acquired pneumonia who had shortness of breath on exertion. Chest computed tomography confirmed that the patient had suffered a prolonged exposure to charcoal smoke. The presence of bullous fibroemphysema and mediastinal adenopathies was diagnosed. Prevention is the most effective measure to fight this disease. Strict compliance with technical measures and constant monitoring of permitted dust levels should be implemented.

Myocardial Perfusion by Coronary Computed Tomography in the Evaluation of Myocardial Ischemia: Simultaneous Stress Protocol with SPECT / Perfusão Miocárdica por Angiotomografia de Coronárias na Avaliação da Isquemia Miocárdica: Protocolo de Estresse Simultâneo com SPECT

Abstract Background: Functional assessment to rule out myocardial ischemia using coronary computed tomography angiography (CCTA) is extremely important and data on the Brazilian population are still limited. Objective: To assess the diagnostic performance of myocardial perfusion by CCTA in the detection of severe obstructive coronary artery disease (CAD) compared with single-photon emission computerized tomography (SPECT). To analyze the importance of anatomical knowledge to understand the presence of myocardial perfusion defects on SPECT imaging that is not identified on computed tomography (CT) scan. Method: A total of 35 patients were evaluated by a simultaneous pharmacologic stress protocol. Fisher's exact test was used to compare proportions. The patients were grouped according to the presence or absence of significant CAD. The area under the ROC curve was used to identify the diagnostic performance of CCTA and SPECT in perfusion assessment. P < 0.05 values were considered statistically significant. Results: For detection of obstructive CAD, CT myocardial perfusion analysis yielded an area under the ROC curve of 0.84 [a 95% confidence interval (CI95%): 0.67-0.94, p < 0.001]. SPECT myocardial perfusion imaging, on the other hand, showed an AUC of 0.58 (95% CI 0.40 - 0.74, p < 0.001). In this study, false-positive results with SPECT are described. Conclusion: Myocardial perfusion analysis by CTA displays satisfactory results compared to SPECT in the detection of obstructive CAD. CCTA can rule out false-positive results of SPECT.

Resumo Fundamento: A avaliação funcional para descartar a isquemia miocárdica utilizando a angiotomografia computadorizada (angio-TC) de coronárias é de extrema importância e dados na população brasileira ainda são escassos. Objetivo: Avaliar o desempenho diagnóstico da perfusão miocárdica pela angio-TC de coronárias na detecção de doença arterial coronariana (DAC) obstrutiva significativa em comparação com a tomografia computadorizada por emissão de fóton único (SPECT; do inglês, single photon emission computerized tomography). Analisar a importância do conhecimento anatômico para entender a presença de defeito de perfusão miocárdica pela SPECT que não é identificado pela tomografia computadorizada (TC). Método: Trinta e cinco pacientes foram avaliados por um protocolo de estresse farmacológico simultâneo. O teste exato de Fisher foi utilizado para comparação entre as proporções. Os pacientes foram agrupados de acordo com a presença ou não de DAC significativa. A área sob a curva foi utilizada para identificar o desempenho diagnóstico da avaliação da perfusão pela angio-TC de coronárias e pela SPECT. Os valores de p < 0,05 foram considerados estatisticamente significativos. Resultados: Para detecção de DAC obstrutiva a avaliação da perfusão miocárdica pela TC teve uma área sob a curva de 0,84 [intervalo de confiança de 95% (IC95%): 0,67 a 0,94, p < 0,001]. Já o estudo da perfusão miocárdica pela SPECT foi de 0,58 (IC95%: 0,40 a 0,74, p < 0,001). Neste estudo, foram descritos falso-positivos pela SPECT. Conclusão: A avaliação da perfusão miocárdica pela angio-TC apresenta resultados satisfatórios em comparação com os da SPECT na detecção de DAC obstrutiva. A angio-TC de coronárias tem capacidade de afastar falso-positivos da SPECT.

Infarto de la arteria de Percheron y temblor de Holmes. Presentación de caso / Infarction of Percheron artery and Holmes tremor. Case presentation

RESUMEN INTRODUCCIÓN: La arteria de Percheron suministra irrigación sanguínea a la región paramediana de ambos tálamos. El temblor de Holmes es un diagnóstico poco frecuente, más aún como resultado de un infarto talámico bilateral. CASO CLÍNICO: Paciente de 72 años de edad a quien se le diagnosticó un temblor de Holmes secundario a un infarto de la arteria de Percheron. El estudio de perfusión cerebral con 99mTc-ECD evidenció marcada hipoperfusión del caudado, cuerpo estriado y tálamo derecho. CONCLUSIÓN: Los estudios funcionales con 99mTc-ECD resultaron útiles para evidenciar la diferencia de captación entre los tálamos con la consecuente disrupción de la vía rubro-tálamo-estriada derecha en este paciente con temblor de Holmes.

SUMMARY INTRODUCTION: Percheron artery supplies blood to the paramedian region of both thalami. Holmes' tremor is an infrequent diagnosis, even more because of a bilateral thalamic infarction. CLINICAL CASE: A 72-year-old patient who was diagnosed of Holmes' tremor secondary to a Percheron artery infarction. The study of brain perfusion with 99mTc-ECD showed marked hypoperfusion of the right caudate, striatum and thalamus. CONCLUSION: Functional studies with 99mTc-ECD were useful to demonstrate the difference in uptake between the thalamus and the consequent disruption of the right-thalamus-striate pathway in this patient with Holmes' tremor.

SPECT/CT with 99mTc-sestamibi for the evaluation of skeletal muscle perfusion after electrical muscle stimulation in athletes.

OBJECTIVE: The purpose of this study was to evaluate the effects of electrical muscle stimulation (EMS) on muscles, using 99mTc-sestamibi SPECT/CT. MATERIALS AND METHODS: We prospectively enrolled 20 consecutive male professional water polo players. The mean age was 25 years (range, 18-36 years). All athletes underwent 99mTc-sestamibi SPECT/CT of the thigh (rectus femoris and vastus medialis muscle groups) before and after EMS. Images were quantified to identify increases in perfusion after EMS. RESULTS: Before EMS, there were no significant differences between the right and left thigh (rectus femoris and vastus medialis muscles) in terms of perfusion (p = 0.4). However, the comparison between the pre- and post-EMS analyses of the same muscle groups showed significant differences in radiotracer uptake (p < 0.001), with a mean increase in perfusion of 128% for the rectus femoris muscle group (95% CI: 0.86-1.61) and 118% for the vastus medialis muscle group (95% CI: 0.96-1.79). CONCLUSION: 99mTc-sestamibi SPECT/CT is an objective means of evaluating blood flow in muscles submitted to EMS, which appears to promote significant increases in such blood flow.

OBJETIVO: O objetivo deste estudo foi avaliar o efeito da estimulação elétrica transcutânea na musculatura esquelética utilizando-se SPECT/CT com 99mTc- sestamibi. MATERIAIS E MÉTODOS: Foram prospectivamente avaliados 20 atletas masculinos de polo aquático (18-36 anos de idade; média de 25 anos). Todos os atletas foram submetidos a SPECT/CT com 99mTc- sestamibi das coxas antes e após estimulação elétrica transcutânea dos grupos musculares reto femoral e vasto medial. As imagens foram quantificadas para identificar aumento da perfusão. RESULTADOS: A comparação da perfusão dos grupos musculares (reto femoral e vasto medial) direito versus esquerdo durante o repouso não demonstrou diferença significativa (p = 0,4). Entretanto, quando comparados esses mesmos grupos musculares antes e após a estimulação elétrica, observou-se diferença significativa na captação do traçador (p < 0,001), com aumento perfusional médio de 128% do grupo reto femoral (IC 95%: 0,86-1,61) e 118% do grupo vasto medial (IC 95%: 0,96-1,79) no grupo estimulado. CONCLUSÃO: A SPECT/CT com 99mTc- sestamibi é capaz de demonstrar de forma objetiva que a estimulação elétrica transcutânea aumenta significativamente o fluxo sanguíneo muscular.

SPECT/CT with 99mTc-sestamibi for the evaluation of skeletal muscle perfusion after electrical muscle stimulation in athletes / SPECT/CT com sestamibi-99mTc para avaliação da perfusão após estímulo elétrico da musculatura esquelética em atletas

Abstract Objective: The purpose of this study was to evaluate the effects of electrical muscle stimulation (EMS) on muscles, using 99mTc-sestamibi SPECT/CT. Materials and Methods: We prospectively enrolled 20 consecutive male professional water polo players. The mean age was 25 years (range, 18-36 years). All athletes underwent 99mTc-sestamibi SPECT/CT of the thigh (rectus femoris and vastus medialis muscle groups) before and after EMS. Images were quantified to identify increases in perfusion after EMS. Results: Before EMS, there were no significant differences between the right and left thigh (rectus femoris and vastus medialis muscles) in terms of perfusion (p = 0.4). However, the comparison between the pre- and post-EMS analyses of the same muscle groups showed significant differences in radiotracer uptake (p < 0.001), with a mean increase in perfusion of 128% for the rectus femoris muscle group (95% CI: 0.86-1.61) and 118% for the vastus medialis muscle group (95% CI: 0.96-1.79). Conclusion: 99mTc-sestamibi SPECT/CT is an objective means of evaluating blood flow in muscles submitted to EMS, which appears to promote significant increases in such blood flow.

Resumo Objetivo: O objetivo deste estudo foi avaliar o efeito da estimulação elétrica transcutânea na musculatura esquelética utilizando-se SPECT/CT com 99mTc- sestamibi. Materiais e Métodos: Foram prospectivamente avaliados 20 atletas masculinos de polo aquático (18-36 anos de idade; média de 25 anos). Todos os atletas foram submetidos a SPECT/CT com 99mTc- sestamibi das coxas antes e após estimulação elétrica transcutânea dos grupos musculares reto femoral e vasto medial. As imagens foram quantificadas para identificar aumento da perfusão. Resultados: A comparação da perfusão dos grupos musculares (reto femoral e vasto medial) direito versus esquerdo durante o repouso não demonstrou diferença significativa (p = 0,4). Entretanto, quando comparados esses mesmos grupos musculares antes e após a estimulação elétrica, observou-se diferença significativa na captação do traçador (p < 0,001), com aumento perfusional médio de 128% do grupo reto femoral (IC 95%: 0,86-1,61) e 118% do grupo vasto medial (IC 95%: 0,96-1,79) no grupo estimulado. Conclusão: A SPECT/CT com 99mTc- sestamibi é capaz de demonstrar de forma objetiva que a estimulação elétrica transcutânea aumenta significativamente o fluxo sanguíneo muscular.

Estratificación de riesgo de muerte a mediano plazo de pacientes evaluados por enfermedad coronaria con SPECT de perfusión miocárdica bajo efecto de dipiridamol / Predictive value of dipyridamole myocardial perfusion tomography on survival

Background: Dipyridamole (DIP) is the most commonly employed pharmacological stressor for myocardial perfusion tomography (SPECT) in patients unable to reach an adequate work load. Aim: To assess the predictive capacity of DIP SPECT on survival. Material and Methods: We included 985 adults aged 66 ±11 years (45% women) with rest and DIP-SPECT. The main indications for the procedure were coronary artery disease (CAD) screening in 66% and known CAD in 33%. Participants were followed up for a median of 65 months (interquartile range 54 to 86 months). During the follow up, 261 deaths were recorded and 98% had a specified cause in their death certificate. Results: Myocardial SPECT was abnormal in 44% of participants. Transient ischemic defects were observed in 34%, fixed defects concordant with infarction in 27% and post-stress systolic dysfunction in 23%. Twenty five percent of deaths were attributable to cardiac or ischemic cause and 22% to cancer. In a bivariate analysis, the hazard ratio (HR) of death of any cause was lower in females and higher in the presence of CAD. The multivariate analysis showed that being older than 46 years increased the HR of death of any cause. In a bivariate analysis, the HR for cardiac death was higher when the myocardial SPECT showed ischemia, necrosis or left ventricular dilation. In the multivariate analysis, post-stress left ventricular systolic function was associated with a lower risk of cardiac death. Conclusions: An abnormal myocardial SPECT, perfusion abnormalities, left ventricular systolic function or dilation are independent predictors of cardiac death in these participants.

Seguimiento clínico en pacientes con buena capacidad metabólica en la prueba de esfuerzo con SPECT miocárdico / Follow-up of patients with good exercise capacity in stress test with myocardial single-photon emission computed tomography (SPECT)

Background: The evaluation of coronary artery disease (CAD) can be performed with stress test and myocardial SPECT tomography. Aim: To assess the predictive value of myocardial SPECT using stress test for cardiovascular events in patients with good exercise capacity. Material and Methods: We included 102 males aged 56 ± 10 years and 19 females aged 52 ± 10 years, all able to achieve 10 METs and ≥ 85% of the theoretical maximum heart rate and at least 8 min in their stress test with gated 99mTc-sestamibi SPECT. Eighty two percent of patients were followed clinically for 33 ± 17 months. Results: Sixty seven percent of patients were studied for CAD screening and the rest for known disease assessment. Treadmill stress test was negative in 75.4%; 37% of patients with moderate to severe Duke Score presented ischemia. Normal myocardial perfusion SPECT was observed in 70.2%. Reversible defects appeared in 24.8% of cases, which were of moderate or severe degree (> 10% left ventricular extension) in 56.6%. Only seven cases had coronary events after the SPECT. Two major (myocardial infarction and emergency coronary revascularization) and 5 minor events (elective revascularization) ere observed in the follow-up. In a multivariate analysis, SPECT ischemia was the only statistically significant parameter that increased the probability of having a major or minor event. Conclusions: Nearly a quarter of our patients with good exercise capacity demonstrated reversible defects in their myocardial perfusion SPECT. In the intermediate-term follow-up, a low rate of cardiac events was observed, being the isotopic ischemia the only significant predictive parameter.

The Benefits of Prone SPECT Myocardial Perfusion Imaging in Reducing Both Artifact Defects and Patient Radiation Exposure / Benefício da Aquisição de Imagem na Posição Prona em Perfusão Miocárdica com SPECT para Redução de Artefatos e Exposição do Paciente à Radiação

AbstractBackground:Prone imaging has been demonstrated to minimize diaphragmatic and breast tissue attenuation.Objectives:To determine the role of prone imaging on the reduction of unnecessary rest perfusion studies and coronary angiographies performed, thus decreasing investigation time and radiation exposure.Methods:We examined 139 patients, 120 with an inferior wall and 19 with an anterior wall perfusion defect that might represented attenuation artifact. Post-stress images were acquired in both the supine and prone position. Coronary angiography was used as the “gold standard” for evaluating coronary artery patency. The study was terminated and rest imaging was obviated in the presence of complete improvement of the defect in the prone position. Quantitative interpretation was performed. Results were compared with clinical data and coronary angiographic findings.Results:Prone acquisition correctly revealed defect improvement in 89 patients (89/120) with inferior wall and 12 patients (12/19) with anterior wall attenuation artifact. Quantitative analysis demonstrated statistically significant difference in the mean summed stress scores (SSS) of supine and mean SSS of prone studies in patients with disappearing inferior wall defect in the prone position and patent right coronary artery (true negative results). The mean difference between SSS in supine and in prone position was higher with disappearing than with remaining defects.Conclusion:Technetium-99m (Tc-99m) tetrofosmin myocardial perfusion imaging with the patient in the prone position overcomes soft tissue attenuation; moreover it provides an inexpensive, accurate approach to limit the number of unnecessary rest perfusion studies and coronary angiographies performed.

ResumoFundamento:Já foi demonstrado que a imagem na posição prona minimiza a atenuação dos tecidos diafragmáticos e da mama.Objetivos:Determinar o papel da imagem na posição prona na redução de estudos de perfusão em repouso e angiografias coronárias realizadas de forma desnecessária, assim diminuindo o tempo de investigação e exposição à radiação.Métodos:Foram examinados 139 pacientes, 120 com um defeito de perfusão da parede inferior e 19 com defeito de perfusão da parede anterior que pudessem representar um artefato de atenuação. Imagens pós-estresse foram adquiridas nas posições supina e prona. A angiografia coronária foi usada como o “padrão ouro” para avaliar a patência da artéria coronária. O estudo foi encerrado e a imagem em repouso não foi necessária na presença de melhoria completa do defeito na posição prona. Uma interpretação quantitativa foi realizada. Os resultados foram comparados com os dados clínicos e achados angiográficos.Resultados:A aquisição de imagem na posição prona revelou corretamente a melhoria do defeito em 89 pacientes (89/120) com artefato de atenuação na parede inferior e 12 pacientes (19/12) na parede anterior. A análise quantitativa demonstrou diferença estatisticamente significante nas somas dos escores de estresse (SSS) médios nos estudos da posição supina e SSS médios dos estudos na posição prona em pacientes com desaparecimento do defeito da parede inferior na posição prona e artéria coronária patente (resultados negativos verdadeiros). A diferença média dos SSS nas posições supina e prona foi maior com os defeitos desaparecidos do que com os que permaneceram.Conclusão:A cintilografia de perfusão miocárdica com Tecnécio-99m (Tc-99m) tetrofosmin com o paciente na posição prona supera a atenuação de tecidos moles; Além disso, oferece uma abordagem precisa e de baixo custo para limitar o número de estudos de perfusão em repouso e realização de angiografias coronárias desnecessárias.

The use of spect/ct in the evaluation of heterotopic ossification in para/tetraplegics.

OBJECTIVE: To evaluate the stage of maturation and the metabolism of neurogenic heterotopic ossification by using SPECT/CT. METHODS: A total of 12 medical records of patients with spinal cord injury, all of them classified according to the ASIA protocol (disability scale from the American Spinal Injury Association) in complete lesion (A) and partial lesions (B, C and D) and registered at the Laboratory of Biomechanics and Rehabilitation of the Locomotor System, were submitted to SPECT/CT evaluation. RESULTS: Sixteen hips with heterotopic ossification observed in X-ray were studied and only two (12.5%) had high osteoblastic activity. Five hips showed medium activity, three (18.75%) low activity and six (37.5%) did not present any activity detected by SPECT/CT. CONCLUSION: SPECT/CT helps to determinate which patients have a greater risk of relapse after surgical resection, proving to be a useful imaging study in preoperative evaluation that can be used to determinate the postoperative prognosis of these patients. Level of Evidence III, Investigating a Diagnostic Test.

The use of spect/ct in the evaluation of heterotopic ossification in para/tetraplegics

Objective: To evaluate the stage of maturation and the metabolism of neurogenic heterotopic ossification by using SPECT/CT. Methods: A total of 12 medical records of patients with spinal cord injury, all of them classified according to the ASIA protocol (disability scale from the American Spinal Injury Association) in complete lesion (A) and partial lesions (B, C and D) and registered at the Laboratory of Biomechanics and Rehabilitation of the Locomotor System, were submitted to SPECT/CT evaluation. Results: Sixteen hips with heterotopic ossification observed in X-ray were studied and only two (12.5%) had high osteoblastic activity. Five hips showed medium activity, three (18.75%) low activity and six (37.5%) did not present any activity detected by SPECT/CT. Conclusion: SPECT/CT helps to determinate which patients have a greater risk of relapse after surgical resection, proving to be a useful imaging study in preoperative evaluation that can be used to determinate the postoperative prognosis of these patients. Level of Evidence III, Investigating a Diagnostic Test. .

Imagem Molecular / Molecular Imaging

Imagem molecular é denominação relativamente recente para procedimentos diagnósticos por imagem que envolvem reações entre agentes de imagem e moléculas-alvo específicas, como enzimas e receptores celulares. Essencialmente, um agente de imagem se constitui de uma porção que interage com um alvo específico, enzima ou receptor celular e uma porção que permite a sua detecção, como, por exemplo, um elemento radioativo, uma partícula magnética ou uma molécula fluorescente. A imagem molecular permite abordar processos biológicos nos níveis celular e subcelular, em organismos vivos intactos. Embora a Medicina Nuclear seja o método, de longe, mais utilizado na área do diagnóstico por imagem que se enquadra na imagem molecular, novas abordagens envolvendo a fluorescência, a ressonância magnética e a ultrassonografia, entre outros, despontam com grande potencial para emprego clínico e pré-clínico. São apresentados exemplos de abordagens pelos diversos métodos de imagem.

Molecular Imaging is a relatively new denomination for diagnostics by imaging procedures that involve reactions between imaging agents and targeting molecules such as enzymes and cellular receptors. Essentially, an imaging agent has a targeting component that interacts with the enzyme or cellular receptors and a component that can be detected, for example, a radioactive element, a magnetic particle or a fluorescent molecule. Molecular Imaging is used to study biological processes at the cellular and sub-cellular levels within intact living organisms. Although Nuclear Medicine has been by far the method more utilized in diagnostic imaging that can be considered Molecular Imaging, new approaches with fluorescence, Magnetic Resonance Imaging and Ultrasound, among others, have a great potential for clinical and preclinical studies. Examples of studies with these methods are presented.

Análisis de los estudios de perfusión posangioplastia: El tiempo entre angioplastia y perfusión. Reestenosis e isquemia / Analysis of Perfusion Studies following Coronary Angioplasty: Time Interval between Angioplasty and Perfusion. Restenosis and Ischemia

Introducción Los consensos internacionales coinciden en señalar que el mejor momento para analizar pacientes posangioplastia con estudios de perfusión es alrededor del sexto mes. Sin embargo, por diversos motivos, los cardiólogos los indican más anticipadamente. Objetivos Determinar los defectos de perfusión reversibles (DPR), el tiempo transcurrido entre la angioplastia (ATC) y la perfusión, los resultados “falsos positivos”, el monto isquémico en pacientes sin lesiones y con ellas en otros vasos no tratados con ATC y el motivo del pedido del SPECT. Material y métodos La población del estudio asignada a dos grupos estuvo conformada por un total de 64 pacientes consecutivos con primer SPECT en el año subsiguiente a una ATC. Grupo 1: 44/64 pacientes (68,8%) sin lesiones en otros vasos distintos del de la ATC y grupo 2: 20/64 pacientes (31,2%) con lesiones en otros vasos distintos del de la ATC. La edad promedio fue de 57,3 ± 10 años. Se investigaron los defectos de perfusión sobre la base del análisis visual semicuantitativo con un modelo de 17 segmentos ya validado. Resultados Del total de 64 pacientes, se detectaron DPR en 12 (18,7%): 9/44 (20,4%) del grupo 1 y 3/20 (15%) del grupo 2. Hubo 3/12 (25%) falsos positivos que correspondieron al primer mes posangioplastia, dos con balón y uno con stent. Dos se confirmaron con estudio SPECT tardío y uno con cinecoronariografía, todos del grupo 1. El tiempo entre ATC y SPECT fue: en el primer trimestre en 33 pacientes, en el segundo trimestre en 22 pacientes y en el tercer trimestre o después en 9 pacientes. El triple puntaje (score) no reveló diferencias significativas entre ambos grupos. PSE: 5,3 ± 3,07 en el grupo 1 y 7 ± 4,5 en el grupo 2; p > 0,99. PSR: 1,66 ± 1,73 en el grupo 1 y 0,6 ± 1,15 en el grupo 2; p > 0,99. PSD: 4,3 ± 1,7 en el grupo 1 y 6,3 ± 3,5 en el grupo 2; p > 0,99. Los motivos fueron: control en 49/64 (76,5%) y síntomas en 15/64 (23,4%). El angor se correlacionó con DPR en 1/9 pacientes (11,1%). Conclusiones En el 51,5% de los pacientes, el SPECT se efectuó en los primeros 3 meses posangioplastia. No hubo diferencias en monto isquémico entre individuos sin lesiones y con ellas en otros vasos. En el 25% de los pacientes con DPR, los resultados fueron falsos positivos y los estudios se efectuaron durante el primer mes posangioplastia. En el 76,5% de los estudios SPECT, el motivo fue el control y hubo baja correlación entre presencia de síntomas y estudios con isquemia.

Background International guidelines coincide in recommending that the best time to perform perfusion studies in patients undergoing coronary angioplasty is about six months following the procedure. However, cardiologists order these studies earlier, for several reasons. Objectives To determine reversible perfusion defects (RPDs), time interval between percutaneous transluminal coronary angioplasty (PTCA) and perfusion test, “false positive” results, ischemic burden in patients without coronary lesions and with coronary lesions in other vessels that were not treated with PTCA, and reasons for ordering a SPECT. Material and Methods Sixty four consecutive patients undergoing a first SPECT during the first year following a PTCA were included in two groups. Group 1: 44/64 patients (68.8%) without lesions in other coronary arteries that had not been treated with PTCA and group 2: 20/64 patients (31.2%) with lesions in other coronary arteries that had not been treated with PTCA. Mean age was 57.3±10 years. Perfusion defects were assessed based on a semiquantitative visual analysis using a validated model of 17 segments. Results A total of 12 patients (18.7%) out of 64 presented RPDs: 9/44 (20.4%) in group 1 and 3/20 (15%) in group 2. There were 3/12 (25%) false positive results during the first month following two balloon angioplasties and one stent implant. Two of these results were confirmed by SPECT performed later and one by coronary angiography; all patients belonged to group 1. Time interval between PTCA and SPECT was as follows: first trimester in 33 patients, second trimester in 22 patients and third trimester or later in 9 patients. There were no significant differences between both groups in the triple score. SSS: 5.3±3.07 in group 1 and 7±4.5 in group 2; p >0.99. SRS: 1.66±1.73 in group 1 and 0.6±1.15 in group 2; p >0.99. SDS: 4.3±1.7 in group 1 and 6.3±3.5 in group 2; p >0.99. Reasons for test ordering were: control study in 49/64 (76.5%) and presence of symptoms in 15/64 (23.4%). A positive correlation between angina and RPDs was seen in 1/9 patients (11.1%). Conclusions SPECT was performed in 51.5% of patients within 3 months following angioplasty. No differences in ischemic burden among patients without coronary lesions or with lesions in other vessels were reported. False positive results were observed in 25% of patients with RPDs who were evaluated during the first month following angioplasty. SPECT was ordered as a control study in 76.5% of cases and there was low correlation between the presence of symptoms and studies positive for ischemia.