Use of PET/CT as a diagnostic tool in various clinical scenarios related to systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic disease mediated by immune complexes of unknown aetiology that generates excessive production of autoantibodies against components of the cell nucleus, generating multisystemic involvement affecting organs or systems such as the central nervous, cardiovascular, haematolymphoid, musculoskeletal, kidney, serous, skin and subcutaneous tissue cells, among others. 2-Fluoro-2-deoxyglucose (FDG) is a glucose analogue that has been shown to be a useful diagnostic tool to establish the initial systemic involvement of this disease and response to the various treatments used.

El lupus eritematoso sistémico (LES) es una enfermedad sistémica mediada por inmunocomplejos de etiología desconocida, la cual genera una producción excesiva de autoanticuerpos contra componentes del núcleo celular. Esto último conlleva un compromiso multisistémico que afecta a órganos o sistemas como el nervioso central, el cardiovascular, el hematolinfoide, el musculoesquelético, el rinón, las serosas, la piel y el tejido celular subcutáneo, entre otros. La 2-fluoro-2-desoxiglucosa (FDG) es un análogo de la glucosa que ha mostrado ser una herramienta diagnostica útil para establecer el compromiso sistémico inicial de esta enfermedad y la respuesta a los diversos tratamientos.

Findings in [99mTc]MAA SPECT/CT in the diagnosis and follow-up of pulmonary embolism after infection by SARS-CoV-2 (COVID-19).

SARS-CoV-2 (COVID-19) infection is a current public health problem that has been shown to cause multiple complications, including pulmonary thromboembolism. The first presented case is a 59-year-old woman with a history of COPD, paroxysmal atrial fibrillation and COVID-19 infection in September 2020, consultation in December 2020 for atypical chest pain with suspected PE, AngioCT of pulmonary vessels was performed negative for emboli, subsequently [99mTc]Tc MAA SPECT/CT was indicated with a report of multiple triangular defects concerning acute pulmonary thromboembolism. A second case is a 70-year-old man with a history of dyslipidaemia, presented COVID-19 infection in September 2020 with a complication of PE with involvement of the left pulmonary artery, followed by [99mTc]Tc MAA SPECT/CT report multiple triangular and not triangles defects concerning pulmonary thromboembolism with signs of reperfusion.

Is there a consensus between clinical practice guidelines for conventional and molecular nuclear medicine studies in parathyroid pathology?

Hyperparathyroidism is a common calcium metabolic disorder, characterized by the presence of high concentrations or inappropriately normal concentrations of parathyroid hormone (PTH) in the context of high calcium. Pharmacological and surgical management is available as treatment. The objective of diagnostic imaging is to determine the location of the causal lesion. For these purposes, non-invasive methods can be divided into anatomical or functional studies, with nuclear medicine studies being in the latter category. The objective of this review, is to establish the similarities and differences that exist in the clinical practice guidelines on conventional and molecular nuclear medicine studies in parathyroid disease.

Encefalitis límbica asociada a anti-Caspr2: contribución del análisis visual ayudado de las imágenes PET con 18F-FDG mediante comparación con una base de datos de normalidad / Caspr2 antibody-associated limbic encephalitis: contribution of visual aided analysis of 18F-FDG PET images using normal database comparison

Un inicio temprano de la inmunoterapia es fundamental para mejorar el pronóstico de los pacientes con encefalitis aguda de origen autoinmune (EAI). Se ha propuesto un nuevo abordaje clínico para el diagnóstico temprano basado en aspectos clínicos y pruebas complementarias, pero estas pueden tener una sensibilidad limitada principalmente en las primeras semanas. Mientras que las formas más comunes de EAI (anti-LGI-1 y anti-NMDAR), muestran frecuentemente patrones de PET con 18Flúor-fluordeoxiglucosa (PET-FDG) consistentes, las anti-Caspr2 son menos frecuentes y los patrones de PET-FDG no están establecidos. En nuestra experiencia la PET-FDG en la EAI anti-Caspr2 presenta un hipermetabolismo temporal medial y un déficit difuso cortical, incluso con pruebas complementarias negativas. No obstante, es necesaria la estandarización del análisis de las imágenes PET mediante métodos basados en vóxeles con comparación con bases de datos de normalidad para definir con claridad las áreas de metabolismo alterado que pueden pasar desapercibidas al análisis visual

Early immunotherapy is of paramount importance for a positive outcome in patients suffering acute encephalitis of autoimmune origin (AIE). A new approach for early diagnosis based on clinical presentation and complementary tests has been proposed, but not all these tests show positive findings in the first weeks. While common forms of AIE (anti-LGI-1 and anti-NMDAR antibodies) exhibit consistent 18Fluor-fluorodeoxiglucose (FDG-PET) patterns in many cases, the anti-Caspr2 form of AIE is infrequent and FDG-PET patterns have not been well characterized. In our experience, FDG-PET in anti-Caspr2 limbic encephalitis shows medial temporal hypermetabolism and diffuse cortical hypometabolism, even in the absence of findings in these tests. However, it is necessary to standardize PET image analysis by means of visual and voxel-based methods compared to normal databases to define the areas of pathological metabolism that may go unnoticed when using visual analysis exclusively

Caspr2 antibody-associated limbic encephalitis: contribution of visual aided analysis of 18F-FDG PET images using normal database comparison. / Encefalitis límbica asociada a anti-Caspr2: contribución del análisis visual ayudado de las imágenes PET con 18F-FDG mediante comparación con una base de datos de normalidad.

Early immunotherapy is of paramount importance for a positive outcome in patients suffering acute encephalitis of autoimmune origin (AIE). A new approach for early diagnosis based on clinical presentation and complementary tests has been proposed, but not all these tests show positive findings in the first weeks. While common forms of AIE (anti-LGI-1 and anti-NMDAR antibodies) exhibit consistent 18Fluor-fluorodeoxiglucose (FDG-PET) patterns in many cases, the anti-Caspr2 form of AIE is infrequent and FDG-PET patterns have not been well characterized. In our experience, FDG-PET in anti-Caspr2 limbic encephalitis shows medial temporal hypermetabolism and diffuse cortical hypometabolism, even in the absence of findings in these tests. However, it is necessary to standardize PET image analysis by means of visual and voxel-based methods compared to normal databases to define the areas of pathological metabolism that may go unnoticed when using visual analysis exclusively.

Pertinencia de la gammagrafia de tiroides en un servicio de medicina nuclear de referencia del oriente colombiano / Relevância da cintilografia da tireoide em um centro de referência de medicina nuclear no leste colombiano / Pertinence of Thyroid Scan in a Nuclear Medicine Department in Eastern Colombia

Introducciَn: La gammagrafia de tiroides es un examen frecuentemente empleado en el estudio de la enfermedad tiroidea. Se recomienda su realizaciَn en el paciente con tirotoxicosis, nَdulo tiroideo con citologيa indeterminada y en la bْsqueda de tiroides ectَpica. Objetivo: Determinar la pertinencia de la solicitud de la gammagrafia tiroidea en un servicio de medicina nuclear de referencia del oriente colombiano. Metodologia: Estudio observacional, corte transversal retrospectivo tipo descriptivo. Se evaluaron las gammagrafias de tiroides realizadas en la unidad de medicina nuclear de la clيnica Carlos Ardila Lulle durante 3 meses consecutivos que en la hoja de solicitud incluyeran todas las variables de interés. Se registrَ la indicaciَn del estudio, formaciَn académica del médico que solicitaba el examen, sexo del paciente, presencia concomitante de TSH con su valor respectivo y el consumo de levotiroxina previo al examen. Adicionalmente se registrَ el resultado gammagrلfico. Resultados: 277 gammagrafيas fueron analizadas, 244 (88%) eran mujeres. EL 67% no estaban correctamente indicadas y de estas el 32% de los pacientes estaban recibiendo suplencia hormonal, la cual fue suspendida 25 dيas antes de la realizaciَn del examen. Los médicos generales y médicos especialistas no endocrinَlogos tienen la probabilidad de 9.08 veces y 9.37 veces respectivamente de no indicar adecuadamente la gammagrafيa tiroidea respecto a los médicos endocrinَlogos. Conclusiones: Dos de cada 3 gammagrafيas tiroideas que se realizaron en un servicio de medicina nuclear de referencia del oriente colombiano no estلn adecuadamente indicadas, teniendo esto un impacto en la salud pْblica.

Introduction: Thyroid scan is a test frequently used in the study of thyroid diseases. It is recommended to perform it in patients presenting thyrotoxicosis, thyroid nodules with indeterminate cytology and when diagnosing ectopic thyroid. Our objective was to determine the pertinence of ordering thyroid scan in a nuclear medicine department in eastern Colombia. Methodology: Observational, retrospective, and cross-sectional descriptive study. Thyroid scans including relevant variables performed in the nuclear medicine department at Carlos Ardila Lulle hospital were evaluated during 3 consecutive months. The indication of the study, academic background of physician requesting the test, patient’s gender, concomitant presence of TSH with its respective value, and intake of Levothyroxine before test. Test results were also taken into account. Results: Out of the 277 performed scans, 244 (88%) were women. 67% of them were not correctly indicated, and 32% of these patients were taking hormonal supplements, which was suspended 25 days before performing the test. General practitioners and consultants without specialization in endocrinology have a 9.08 and 9.37 probability respectively, of not indicating correctly the thyroid scan compared to endocrinologists. Conclusions: Two out of 3 thyroid scans performed in a nuclear medicine department in Eastern Colombia are not correctly indicated, producing a big impact in public health.(au)

Introduçمo: A cintilografia da tireَide é um teste muito usado no estudo de doenças da glândula tireَide. O monitoramento é recomendado em doentes com tireotoxicose, nَdulos de tireَide com citologia indeterminada e suspeita de tireَide ectَpica. Objetivo: Nosso objetivo foi determinar a pertinência do pedido de cintilografia da tireَide em um centro de referência de medicina nuclear no leste da Colômbia. Metodologia: Estudo de observaçمo, com corte transversal retrospectivo e descritivo. As cintilografias realizadas na unidade de medicina nuclear da clيnica Carlos Ardila Lulle foram avaliados por 3 meses consecutivos, incluindo no formulلrio todas as variلveis de interesse. Registrou-se a indicaçمo do estudo, a formaçمo acadêmica do médico que pediu o exame, o sexo do paciente, a presença concomitante de TSH com seu respectivo valor e o uso de levotiroxina antes de fazer o teste. Além disso foi registrado o resultado da cintilografia. Resultados: 277 cintilografias foram analisadas, 244 (88%) eram de mulheres. 67% nمo foram devidamente identificados e, destes, 32% dos pacientes estavam recebendo substituiçمo hormonal, que foi suspensa 25 dias antes do exame. Os clيnicos gerais e os especialistas nمo endocrinologistas têm a probabilidade de 9,08 vezes e 9,37 vezes, respectivamente, de nمo indicar corretamente o exame da tireَide, em relaçمo aos médicos endocrinologistas. Conclusُes: Dois de cada três exames de tireَide que sمo feitos num centro de referência de medicina nuclear no leste colombiano nمo estمo corretamente solicitados, o que gera grande impacto na saْde pْblica.