ABSTRACT
Aim/Introduction: The aim of the study was to assess the presence of lymph node uptake (LNU) in patients who had received a COVID-19 vaccine and to evaluate its association with patient characteristics, type of vaccines, and PET/CT radiotracers. Material(s) and Method(s): 361 patients who underwent a PET/CT scan with 18F-FDG (FDG), 68Ga-PSMA (PSMA), or 11C-Choline (CHOL) performed in two EARL PET/CT accredited centers, from May to July 2021, and who had received single or double dose of COVID-19 vaccine (mRNA-based and viral-vector) were selected. Data from age, tumor histology, type of vaccine, location of LNU and time from vaccination (time- Vacc) were prospectively collected. A retrospective analysis of scans was conducted evaluating the presence/absence of LNU (chisquare test). Additionally we performed a semiquantitative analysis (SUVmax of LNU), to explore possible differences according to type and number of vaccination doses, time-Vacc, patient age and tumor hystologies (independent t-tests). Result(s): From the 361 eligible subjects (median age: 67 years), 319 (88%) underwent PET/CT with FDG, 23 (6.3%) with PSMA, 19 (5,2%) with CHOL. 296 (82%) subjects received mRNA-based vaccine, 62 (17%) viral-vector (V-V) and 3 (1%) received mixed vaccines. Positive LNU was seen in 203 subjects (56.2%) independently of vaccine types (mRNA=59.68, V-V=55.7, p=0.74) and number of doses (1 dose: V-V=56.76%, mRNA=58.62 p=0.83;2 doses: mRNA=55%). Similar frequency of LNU positivity was observed using FDG and CHOL (57.6% and 57.8%, respectively), while with PSMA only 34.8% showed LNU positivity. LNU limited to ipsilateral axillar region was the most frequent location (global: 70.44%;FDG:69.6%;CHOL:63.6%;PSMA:100%), followed by both ipsilateral axillar and retropectoral region (global: 18.72%;CHOL: 36.4%). Positive LNU was less frequent in older patients (p=0.007), and ranged between 40 to 68% among the neoplastic pathologies, with the exception of multiple myeloma (15.8%;p=0.001). Positive LNU appeared in most cases in the first week post-vaccination (82%), persisted in second and third week (68.49%, 62.64%), and decreased after the fourth week (38.8%). Moreover, an inverse correlation between the time-Vacc and the SUVmax value calculated in the LNU using FDG (2.82 +/- 1.44;p=0.008) was observed. Conclusion(s): Patients referred to a FDG or CHOL PET scan due to diverse neoplastic diseases displayed high percentage of axillar LNU one week after COVID-19 vaccination, independently of vaccine type and number of doses. Our results also suggest a lower percentage of positive LNU in older subjects, patients with multiple myeloma, and when using PSMA-PET.
ABSTRACT
Introduction: Due to the harmful economic and social effects caused by the confinement of people, the Colombian government entities have planned an intelligent quarantine based on the interpretation of the behavior in the curve data, from which they affirm that it has shown a reduction during the last days. Objective: To highlight the importance of the analysis of non-linear correlation models and all the statistical inference procedures for the design of a mathematical model that allows the prediction of data based on the age of positive cases of COVID-19 in Colombia. Material and Methods: The daily results are based on the information obtained from the official website of the Colombian National Resultados: Con un R2 de 0,9969 muy cercano a 1, y una prueba de hipótesis que garantiza la veracidad de la hipótesis alternativa, el modelo matemático de regresión que más se aproxima al comportamiento real de los datos de crecimiento de la COVID-19 es cuadrático. Conclusiones: El modelo cuadrático es positivo y creciente, mientras el número de contagios siga creciendo, por lo tanto, este momento no es ideal de hablar de un aplanamiento de la curva. Si el crecimiento es constante, el modelo podría tener una tendencia exponencial. Palabras claves: Predicción, curva de crecimiento, modelos de regresión, número de contagios. Institute of Health. The total data are analyzed through the R-Kward free software (R Library). The aim of the analysis is to show the value of the correlation matrix, hypothesis test, r2 and the ideal correlation model, with which prediction is made. Results: With an R2 value of 0.9969 very close to 1 and a hypothesis test that guarantees the veracity of the alternative hypothesis, the ideal mathematical model that aligns the growth data of COVID-19 is quadratic. Conclusions: The quadratic model is positive and increasing as long as the number of infections continue to grow;therefore, it is not an ideal moment to speak of a flattening of the curve. If the growth is constant, the model could have an exponential trend. © 2020 Universidad de Ciencias Medicas de La Hab. All rights reserved.