Utilidad de la 18f-colina pet/tc en hiperparatiroidismo primario persistente o recurrente: experiencia inicial / Usefulness of 18f-choline pet / tc in persistent or recurrent primary hyperparathyroidism: initial experience

El hiperparatiroidismo persistente/recurrente representa un desafío en la localización del tejido paratiroideo hiperfuncionante. En esta subpoblación, los métodos convencionales ofrecen un menor rédito diagnóstico. La 18F-colina PET/TC podría ser una buena alternativa dada su mejor resolución espacial, capacidad de detectar glándulas ectópicas y la conjunción de la imagen molecular y anatómica. Sin embargo, la evidencia en este subgrupo de pacientes es escasa. Objetivo: evaluar la utilidad de la 18F-colina PET/TC como método de localización en el hiperparatiroidismo persistente o recurrente. Materiales y métodos: se analizaron los pacientes con 18F-colina PET/TC para hiperparatiroidismo entre diciembre de 2015 y enero de 2018 en un centro terciario de alto volumen. Se analizaron el número de lesiones, su localización, tamaño y el Standard Uptake Value máximo (SUV max) en las imágenes tempranas y tardías. Se compararon los resultados con los métodos convencionales. Resultados: 7 de 15 pacientes habían sido operados previamente (persistentes/recurrentes). La 18F-colina PET/TC detectó 6/7 casos (83,33%), la ecografía cervical 1/4 (25%) y el SPECT de paratiroides y la resonancia nuclear magnética 2/5 (40%). El SUV max obtenido fue variable, en la mitad de los casos a los 10 minutos y en los restantes a la hora; el tamaño promedio de las lesiones fue 8,61 mm (6-12 mm). Conclusiones: la 18F-colina PET/TC muestra una alta tasa de detección en los pacientes con hiperparatiroidismo persistente/recurrente. La combinación del comportamiento biológico del PET con los hallazgos morfológicos aportados por la TC con contraste endovenoso le ofrecería ventajas sobre otros estudios que podrían posicionarlo como método de primera línea en esta subpoblación. (AU)

Persistent or recurrent hyperparathyroidism represents a challenge regarding the localization of the hyper-functioning parathyroid tissue. In this subpopulation of hyperpharathyroid patients, conventional methods have a low diagnostic yield. The 18F-choline PET /CT could be a good alternative given its better spatial resolution, ability to detect ectopic glands, and the conjunction of the molecular and anatomical image. However, the evidence in this subgroup of patients is limited. Objective: to evaluate the utility of 18F-choline PET/ CT as a localization method in persistent or recurrent hyperparathyroidism. Materials and methods: patients with 18F-choline PET / CT for hyperparathyroidism between December 2015 and January 2018 in a high-volume tertiary center were included. The number of lesions, and their location, size, and maximum Standard Uptake Value (SUV) in the early and late images were analyzed. The results were compared to conventional methods. Results: 7 of 15 patients had been previously operated (persistent/recurrent). 18F-choline PET / CT detected 6/7 cases (83,33%), cervical ultrasound 1/4 (25%) and parathyroid SPECT and magnetic resonance 2/5 (40%). The maximum SUV was variable, one half at 10 minutes and the other half at 60 minutes; the average size of the lesions was 8.61 mm (6-12 mm). Conclusions: 18F-Choline PET / CT shows a high detection rate in patients with persistent / recurrent hyperparathyroidism. The combination of the biological behavior of PET with the morphological findings provided by CT with intravenous contrast would offer advantages over other studies that could position it as a first line method in this subpopulation. (AU)

Estudo da permeabilidade vascular pulmonar e das junções interendoteliais na malária experimental / Study of pulmonary vascular permeability and interendothelial junctions in experimental malaria

Infecções por Plasmodium spp. podem acarretar em complicações pulmonares (1 a 40% dos casos), que podem resultar no desenvolvimento da síndrome do desconforto respiratório agudo (SDRA). Esta síndrome é caracterizada por inflamação aguda, lesão do endotélio alveolar e do parênquima pulmonar, disfunção e aumento da permeabilidade da barreira alvéolo-capilar pulmonar e, consequente, formação de efusão pleural. Neste sentido, os mecanismos de regulação da permeabilidade das células endoteliais e as junções interendoteliais têm papel crítico na manutenção do endotélio pulmonar. O objetivo do estudo foi determinar precocemente o desenvolvimento da SDRA associada à malária por tomografia computadorizada por emissão de fóton único (SPECT/CT), além de identificar alterações nas junções interendoteliais das células endoteliais pulmonares primárias de camundongos DBA/2 (CEPP-DBA/2), após contato com os eritrócitos parasitados de Plasmodium berghei ANKA (EP-PbA). Os nossos resultados demonstraram que é possível identificar alterações na aeração pulmonar no 5° e 7° dia após a infecção e, consequentemente, diferenciar os animais que desenvolveriam SDRA daqueles que evoluiriam para hiperparasitemia (HP). Além disso, observamos em CEPP-DBA/2 que o contato direto com EP-PbA aumenta da abertura das junções interendoteliais e da permeabilidade vascular. Assim, avaliamos a diminuição da expressão das proteínas das junções interendoteliais que contribuem para o aumento da permeabilidade vascular, por imunofluorescência e Western Blot. Apesar da SDRA ter sido identificada há mais de 50 anos, ainda não se conhece formas de diagnóstico precoce e os mecanimos efetivos de desenvolvimento desta enfermidade, que permitam um tratamento efetivo e que evite a morte do paciente. Portanto, sugere-se que a técnica de SPECT/CT seja uma importante ferramenta de diagnóstico para identificação precoce de SDRA associado a malária

Infections by Plasmodium spp. can lead to pulmonary complications (1 to 40% of the cases), that can result in the development of acute respiratory distress syndrome (ARDS). This syndrome is characterized by the acute inflammation, injury of the alveolar endothelium and pulmonary parenchyma, dysfunction and increased permeability of the pulmonary alveolar-capillary barrier and, consequently, formation of pleural effusion. In this aspect, mechanisms of regulation of endothelial cell permeability and interendothelial junctions play a critical role in the maintenance of the pulmonary endothelium. The present study aimed to determine the early development of single-photon emission computed tomography (SPECT/CT) associated malaria ARDS in addition to identifying changes in the interendothelial junctions of the primary pulmonary endothelial cells of DBA/2 mice (CEPP-DBA/2) after contact with erythrocytes infected with Plasmodium berghei ANKA (EP-PbA). Our results demonstrated that is possible to identify changes in lung aeration on the 5th and 7th day after infection and, consequently, differentiate the animals that should develop ARDS from those that would evolve to hyperparasitemia (HP). In addition, we observed in CEPP-DBA/2 that direct contact with EP-PbA increases the opening of the interendothelial junctions and vascular permeability. Thus, we evaluated that decrease the expression of interendothelial junction proteins contribute to the increase of vascular permeability, by immunofluorescence and Western Blot. Although ARDS was identified more than 50 years ago, it is not yet known what forms of early diagnosis, and the effective mechanisms of development of this disease, that allow an effective treatment and that prevent the death of the patient. Therefore, it is suggested that the SPECT/CT technique is a valuable tool to promote the early identification of ARDS associated with malaria

Technetium-99m-labelled sulesomab [Leukoscan] in the evaluation of soft tissue infections

To perform a retrospective review of all patients receiving technetium-99m [[99m]Tc]-labelled sulesomab over a 4-year period to determine if soft tissue infections can be accurately identified. We reviewed the results of 124 99mTc-sulesomab studies performed over a 4-year period. Of these, 34 were performed for undiagnosed fever in which soft tissue infection was suspected to be the main cause. The patients' clinical notes, microbiology reports and other imaging findings were reviewed to determine the clinical outcome following the scan. The scans were regarded as being true-positives if [i] uptake correlated with the site from which fluid or tissue was obtained and which grew bacteria, and/or [ii] the site of abnormality was reported as having an infection on other imaging or [iii] there was a clinical correlation with the referring clinician's evaluation of the patient. Planar imaging was performed using standard protocols, together with single-photon emission computed tomography [if required] at 1 and 4 h after injection of 20-30 mCi [740-1,110 MBq] 99mTc-sulesomab. Three patients were unevaluable. In the remaining 31 patients, 21 99mTc-sulesomab studies were regarded as true-positives and 6 patients had true-negative scans. One patient had a false-positive scan [abnormal uptake with negative microbiology] and 3 had false-negative scans [infection confirmed but a negative scan]. In suspected soft tissue infection, 99mTc-sulesomab imaging has a sensitivity of 88% with a specificity of 86% and overall accuracy of 87%. 99mTc-sulesomab provides an accurate method of imaging for suspected soft tissue infection, which is also fast and convenient, as cell labelling is not required

Tomografía computada de emisión fotón único (SPECT) encefálica, en el diagnóstico diferencial de las demencias / Cerebral single photon emission computed tomography (SPECT) in the differential diagnosis of dementias

Introducida hace ya dos décadas atrás, la tomografía de emisión de fotón único SPECT, ha tenido su mayor auge en éste último decenio, empleándose con éxito en la evaluación del flujo sanguíneo cerebral (FSC), ya sea en forma global como regional de sus diferentes territorios, permitiendo así una mejor comprensión, tanto de su fisiología como los cambios que allí ocurren en diferentes entidades clínicas. Esta técnica se desarrolló a partir de la experiencia adquirida en el uso de la tomografía de emisión de positrones (PET), que utiliza radiofármacos de vida media ultracorta como el oxígeno 15, carbono 11, clucosa marcada con flúor 18 entre otros, con los cuales es posible el estudio del metabolismo cerebral. Dado su alto costo y complejidad, el PET está disponible en pocos centros a nivel muldial. Estos hechos, junto con una mayor disponibilidad de gammacámaras SPECT, condujeron a producción de trazadores de flujo cerebral que se pueden marcar con emisores de fotones simples, en la base que el FSC y el metabolismo se modifican paralelamente. Mientras los métodos de diagnósticos por imágenes como la tomografía axial computada (TAC) y la resonancia nuclear magnética (RNM) nos entregan esencialmente información de carácter morfológico, el SPECT proporciona información principalmente funcional

SPECT-99mTc-HMPAO en un caso de epilepsia parcial continua y encefalitis focal / Single photon emission computed tomography in a case of epilepsia partialis continua and chronic encephalitis

Describimos el caso de una niña de 8 años de edad con epilepsia parcial continua (EPC) con sacudidas clónicas del hemicuerpo izquierdo y con deterioro neurológico progresivo. Los tratamientos antiepilépticos fracasaron en mejorar el cuadro convulsivo. La paciente fue estudiada con SPECT-99mTc-HMPAO, además de electroencefalograma (EEG), tomografía computada (TCC) y resonancia magnética de cráneo (IRM). Durante el periodo ictal, los estudios de SPECT demostraron un aumento del flujo sanguíneo cerebral en el hemisferio cerebral derecho, y durante el periodo interictal, una disminución del flujo sanguíneo en el mismo hemisferio, particularmente en lóbulo temporal y área rolándica. El EEG mostró descargas epileptógenas continuas caracterizadas por puntas y puntas onda en el hemisferio cerebral. La TCC fue normal y la IRM mostró incremento de la señal en el hemisferio cerebral derecho especialmente en región rolándica y lóbulos temporal y frontal. Se programó para lobectomía temporal y corticectomía frontal derecha. Un estudio histopatológico reveló cambios compatibles con encefalitis viral (síndrome de Rasmussen). La paciente ha continuado sin crisis convulsivasa 10 meses de seguimiento y con programa de rehabilitación intensivo. Regresó a la escuela tres meses después de la cirugía caminando con apoyo de un bastón y su IQ fue normal. Este estudio muestra la utilidad del SPECT en el diagnóstico y manejo de la EPC