Marylin Acuña Hernandez

Autoimmune diseases are on the rise, likely due to many factors such as pollution, infections, dietary changes, climate modifications, and exposure to xenobiotics. These diseases impact individuals, society, and healthcare systems. Some diseases are well-known, such as type 1 diabetes, while others are orphan or rare diseases. According to the WHO, rare diseases affect fewer than five people, 10,000 inhabitants, and over 7,000 diseases. These conditions generally have low prevalence, are mostly chronically debilitating, and typically lack treatment. In 2013, the European Society of Nuclear Medicine and the Society of Nuclear Medicine and Molecular Imaging published guidelines for using [18F]FDG (the main radiotracer) in PET/CT studies of inflammation and infection. The use of this radiotracer has expanded in recent decades. Our objective was to describe the use of PET/CT and its various radiotracers in rare or orphan autoimmune diseases classified in ICD-11. To achieve this, we followed the methodology outlined by the Joanna Briggs Institute for scoping reviews. Seventy-seven articles were included in the thematic analysis; 71 were case reports, while the rest were case series and cross-sectional studies. The predominant finding in the PET/CT scans of the different pathologies was an increase in the uptake of various radiotracers, with [18F]FDG being the most commonly used. This diagnostic tool provided a comprehensive view of the systemic involvement of multiple conditions, such as Castleman disease and Cogan syndrome. It helped to identify the primary tumor and guide therapies for diseases like acromegaly.

Thyroid cancer is a common endocrinological malignancy worldwide, accounting for 3% of the global incidence of all cancers. Meta-analyses, systematic reviews, and descriptive reviews mention the use of positron emission tomography / computed tomography (PET/CT) as an alternative to morphological imaging such as computed tomography or magnetic resonance imaging to clarify the diagnosis. The aim: analysis of positron emission tomography/computed tomography tracers in the differential diagnosis of thyroid carcinomas. Materials and methods: Review about PET/CT tracers different than 2-[18F] fluorodeoxyglucose (FDG) in patients with diagnosed differentiated thyroid carcinoma. Evidence Synthesis: PET/CT is an alternative to morphological diagnosis imaging when is inconclusive or negative due to the suspicion of tumor persistence or recurrence, elevation of tumor markers, dedifferentiation thyroid carcinoma, non-conventional therapeutic options. 2-[18F] FDG is the most uses a tracer, but there are scenarios where can be negative or inconclusive, for this reason, in recent years other PET tracers have been used: [124I] NaI, [18F] Tetrafluoroborate, [68Ga] Ga-NOTE-PRGD2 or [18F] AIF-NOTE-PRGD2, [68Ga] Ga-DOTA-FAPI, [18F] Fluorocholine or [11C] C-Choline, [18F] or [68Ga] Ga-PSMA, [68Ga] Ga DOTA-TATE/TOC/NOC/LAN, [18F]-FAZA, L-[methyl-11C] Methionine and [89Zr] DFO-PAS200-Fab. Conclusions. There are multiple radiopharmaceuticals different than 2-[18F] FDG, which can be adequate in the context of differentiated thyroid carcinoma: 2-[18F] FDG PET/CT negative, TENIS syndrome, radioiodine-refractory thyroid cancer suspected, thyroid dedifferentiated carcinoma, and some cases theragnostic tools.

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. 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.

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.

Li-Fraumeni syndrome is a rare disorder caused by abnormalities of the tumor-suppressor protein P53 gene. We present the case of a 26-years-old female diagnosed with bilateral ductal carcinoma. The genetic panel for breast cancer gene 1 (BRCA1) and BRCA2 mutations was negative and positive heterozygous germline tumor protein P53 gene mutations, considering Li-Fraumeni syndrome. A 2-[18F]-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) was used for postsurgical staging to show the right lung hypermetabolic nodule. A lobectomy was accomplished, and histopathology reported pulmonary adenocarcinoma. A year later, oncological follow-up was conducted with 2-[18F]-FDG PET/CT without evidence of abnormalities.

O transplante renal é o tratamento de escolha para a doença renal em estágio terminal. Podem ocorrer várias complicações médicas e cirúrgicas subsequentes, incluindo vasculares (trombose / estenose da veia e / ou artéria renal) que são raras e resultam em perda do enxerto. Apresentamos o caso de um paciente do sexo masculino que, no terceiro dia após o transplante, persiste com anúria e elevação de azoados, realizando um renograma com 99mTc - MAG3 com achados compatíveis de trombose vascular. El trasplante renal es el tratamiento de elección para la enfermedad renal terminal. Pueden presentarse diversas complicaciones médicas y quirúrgicas posteriores, entre ellas las vasculares (trombosis/estenosis de la vena y/o arteria renal) que son poco frecuentes y resultan en la pérdida del injerto. Presentamos el caso de un paciente masculino que al tercer día posterior al trasplante persisten con anuria y elevación de azoados, realizándose renograma con 99m – Tc MAG3 con hallazgos compatibles de trombosis vascular. Kidney transplantation is the treatment of choice for end-stage renal disease. Various medical and surgical complications can occur later, among them the vascular ones (thrombosis / stenosis of the vein and / or renal artery) that are infrequent and result in the loss of the graft. We present the case of a male patient who persisted with anuria and azoate elevation on the third day after transplantation, performing a renogram with 99m - Tc MAG3 with compatible findings of vascular thrombosis.

Se presenta el caso de un paciente con antecedente de adenocarcinoma de próstata y diagnóstico de ACV isquémico con transformación hemorrágica. La gammagrafía ósea con Tc-99m MDP complementada con SPECT e imágenes de fusión con TC cerebral simple, realizada a los 15 días, muestra hipercaptación en la región temporal izquierda, correspondiente al ACV en etapa subaguda. We present the case of a patient with a history of prostate adenocarcinoma with a diagnosis of ischemic stroke with hemorrhagic transformation. Bone scintigraphy with Tc-99m MDP supplemented with SPECT and fusion images with simple cerebral CT, performed at 15 days, shows uptake in the left temporal region, corresponding to stroke in subacute stage. Apresentamos o caso de um paciente com história de adenocarcinoma de próstata com diagnóstico de acidente vascular cerebral isquêmico com transformação hemorrágica. A cintilografia óssea com Tc-99m MDP suplementada com SPECT e imagens de fusão com TC cerebral simple, realizadas aos 15 dias, mostra captação na região temporal esquerda, correspondente ao ACV na fase subaguda.