Multitracer PET/CT with [18F]Fluorodeoxiglucose and [18F]Fluorocholine in the Initial Staging of Multiple Myeloma Patients Applying the IMPeTus Criteria: A Pilot Study.

Initial staging of patients diagnosed with multiple myeloma (MM) can lead to negative results using conventional diagnostic imaging workup, including [18F]Fluorodesoxiglucose ([18F]FDG) PET/CT. The aim of this prospective pilot study was to evaluate the diagnostic efficacy of [18F]Fluorocholine ([18F]FCH) PET/CT in the initial staging of MM patients who were candidates for autologous bone marrow transplant. Materials and Methods: The inclusion criteria of our study were: (a) patients diagnosed with MM; (b) candidates for autologous bone marrow transplant (AT); and (c) studied with [18F]FCH PET/CT and [18F]FDG PET/CT for initial staging less than 4 weeks apart. Imaging analysis included the presence of: bone marrow infiltration, focal bone lesions, and para-medullary or extra-medullary disease, according to the proposed IMPeTus criteria. The analysis was performed per lesion, per patient, and per location. Results: The study population included ten patients. Globally, [18F]FCH PET/CT showed bone marrow uptake in all the patients and visualised 16 more focal lesions than [18F]FDG PET/CT. One patient presented a plasmacytoma, detected by both tracers. Extra-medullary and para-medullary disease was identified with different degrees of uptake by both tracers. In summary, [18F]FCH PET seemed to be superior to [18F]FDG PET/CT in detecting focal bone lesions. SUVmax values were slightly higher in [18F]FCH PET/CT than in [18F]FDG PET/CT. Conclusions: Taking into account the small study population, according to our results, [18F]FCH PET/CT could be a useful tool for staging MM patients.

[18F]FDG PET/CT in the Evaluation of Melanoma Patients Treated with Immunotherapy.

Immunotherapy is based on manipulation of the immune system in order to act against tumour cells, with growing evidence especially in melanoma patients. The challenges faced by this new therapeutic tool are (i) finding valid evaluation criteria for response assessment; (ii) knowing and distinguishing between "atypical" response patterns; (iii) using PET biomarkers as predictive and response evaluation parameters and (iv) diagnosis and management of immunorelated adverse effects. This review is focused on melanoma patients analysing (a) the role of [18F]FDG PET/CT in the mentioned challenges; (b) the evidence of its efficacy. For this purpose, we performed a review of the literature, including original and review articles. In summary, although there are no clearly established or globally accepted criteria, modified response criteria are potentially appropriate for evaluation of immunotherapy benefit. In this context, [18F]FDG PET/CT biomarkers appear to be promising parameters in prediction and assessment of response to immunotherapy. Moreover, immunorelated adverse effects are recognized as predictors of early response to immunotherapy and may be associated with better prognosis and clinical benefit.

Unusual Uptake of [131I] in a Tenosynovial Giant Cell Tumour Relapse in a Patient with Differentiated Thyroid Cancer.

A 77-year-old woman with follicular thyroid cancer underwent total thyroidectomy and subsequent Iodine-131 remnant ablation. She had a history of a wide tenosynovial giant cell tumor (TGCT) of the right wrist and hand that had been resected thirteen years ago. Post-therapeutic scintigraphy and single photon emission computed tomography showed mild uptake on the distal right forearm, wrist and hand. Magnetic resonance imaging and posterior histopathology confirmed a relapse of TGCT. No radioiodine adverse effects were reported after a one-year follow-up. As far as we know, this report is the first in the literature to a TGCT visualized on post-therapy radioiodine scan.

[18F]-FDG PET/CT in oncologic patients with unsuspected asymptomatic infection with SARS-CoV-2.

PURPOSE: Spain has been one of the most affected countries by the COVID-19 pandemic, being among the countries with worse numbers, including the death rate. However, most patients are asymptomatic, although they are very contagious. The objective of this study was to investigate the incidence in oncological patients infected with SARS-CoV-2 that are asymptomatic for COVID-19 and at home and that undergo PET/CT for oncologic indications, nonrelated to COVID-19, finding in the PET/CT lung alterations that are suggestive of SARS-CoV-2 infection. METHODS: During the period of maximum incidence of the global pandemic in one of the most affected regions of Spain, there were 145 patients that met inclusion and exclusion criteria and were included in the study. Imaging findings previously described such as ground-glass opacities with low [18F]-FDG uptake were considered images suspicious for SARS-CoV-2 infection. Patients with these findings were referred to RT-PCR testing and close follow-up to confirm the presence or absence of COVID-19. RESULTS: Suspicious lung imaging findings were present in 7 of 145 patients (4.8%). Five of these 7 patients were confirmed as presenting SARS-CoV-2 infection, this is, COVID-19. In the remaining two, it was not possible to confirm the presence of COVID-19 with RT-PCR, although in one of them, PET/CT allowed an early diagnosis of a lung infection related to a bacterial pneumonic infection that was promptly and adequately treated with antibiotics. CONCLUSION: These results confirm that the prevalence of SARS-CoV-2 infection is higher than suspected and that there are asymptomatic patients that are attending imaging departments to be explored for their baseline oncologic processes. In these patients, PET/CT allows an early diagnosis of COVID-19.

Venous Air Embolism Identified by 18F-Fluorocholine Dual-Phase PET/CT.

ABSTRACT: A 60-year-old woman with primary hyperparathyroidism with previous nonconclusive imaging studies was referred for 18F-fluorocholine (18F-FCH) PET/CT as part of the preoperative diagnostic imaging workup to localize the adenoma before minimally invasive surgery. 18F-FCH PET/CT with dual time point was performed, acquiring immediately and 60 minutes after 18F-FCH administration. The early images demonstrated possible hyperfunctioning parathyroid tissue in the mediastinum, located in the right upper paratracheal space (region 2R), with an incidental iatrogenic subclavian venous air bubble embolism presenting as high uptake in the early images that disappeared in the late images. No symptomatology was reported during the examination.