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Objectives: In the Covid-19 era, there was a surge in the cases of a life-threatening infection of rhinosinonasal mucormycosis. Mucormycosis, popularly known as black fungus, is an infection caused by mycetes mucorales, an aseptate hyphae. Presently, computed tomography (CT) and magnetic resonance imaging (MRI) are commonly used imaging modalities for the management of patients with rhinosinonasal mucormycosis. The present study was aimed to evaluate the role of 18F- FDG PET/CT in the detection of recurrent or residual disease in post-surgical or post antifungal therapy in these patients for further management. Method(s): A total of 10 patients were included in this pilot study of Covid-19 positive patients and histologically proven mucormycosis (by KOH mount). 18F- FDG PET/CT was performed to assess the disease status in 6 postoperative/ post debridement patients and response to antifungal therapy in 4 patients, at an interval of 40 (range = 27-66) days post intervention. Result(s): The mean age of the patients was 45.0 +/- 11.65 years. The male: female ratio was 9:1. The common clinical presentation was ipsilateral facial or orbital pain and swelling. Covid-19 infection was positive in all the patients except one who had CT finding with HRCT score of 10/25 and hence was considered as post Covid-19 infection. Six out of 10 patients were diabetic on oral hypoglycaemic agents or insulin. All patients had a baseline CT/MRI for staging the initial extent of the disease. Surgical debridement was done in 6 out of the 10 patients followed by antifungal therapy (Liposomal Amphotericin B and Pozaconazole). Remaining four patients were treated with antifungal therapy. PET/CTwas performed after an average of 40 days of surgical/medical intervention, in whom clinical symptoms persisted or worsened even on antifungal therapy. 18F-FDG PET/CT showed metabolically active residual disease in all the patients with a mean SUVmax of 9.78 +/- 4.03. Conclusion(s): In the era of ongoing Covid-19 infection, black fungus has been a debilitating disease with high mortality and morbidity. Present study demonstrated that 18F-FDG PET/CT can be an efficient imaging tool for an early surgical/ medical treatment response assessment and restaging.
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Background: Sydenham chorea, or rheumatic chorea, is a movement disorder that is more prevalent among young people, with a mean age at symptom onset between 8 and 9 years. The condition is more common in females. Sydenham chorea is associated with rheumatic fever and is considered the most common cause of acute chorea in children. We believe that the present case is worth reporting since the occurrence of Sydenham chorea as a post-COVID-19 sequela has not been described in Brazil. Case Presentation: We report here the case of a 14-year-old girl with symptoms of acute chorea that emerged 15 days after treatment resolution of COVID-19 (SARS-CoV-2 or severe acute respiratory syndrome coronavirus 2). Brain computed tomography (CT) and magnetic resonance imaging scans showed no changes, and the laboratory tests revealed no signs of an active infectious process. In contrast, neurological positron-emission tomography/CT showed mild glycolytic hypometabolism in the bilateral mesial frontal region. Administration of an oral anticonvulsant resulted in a marked improvement in her symptoms. Conclusion(s): Despite major efforts of the scientific community for discovering treatments, preventive methods, mechanisms of action, and possible sequelae of SARS-CoV-2, there is still a long way to go to better understand this devastating pathological agent that has affected the global population.Copyright © 2023 Camargo and Morcillo.
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Aim: Arterial involvement has been implicated in the coronavirus disease of 2019 (COVID-19). Fluorine 18-fluorodeoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) imaging is a valuable tool for the assessment of aortic inflammation and is a predictor of outcome. We sought to prospectively assess the presence of aortic inflammation and its time-dependent trend in patients with COVID-19. Method(s): Between November 2020 and May 2021, in this pilot, casecontrol study, we recruited 20 patients with severe or critical COVID-19 (mean age of 59+/-12 years), while 10 age and sex-matched individuals served as the control group. Aortic inflammation was assessed by measuring 18F-FDG uptake in PET/CT performed 20-120 days post-admission. Global aortic target to background ratio (GLA-TBR) was calculated as the sum of TBRs of ascending and descending aorta, aortic arch, and abdominal aorta divided by 4. Index aortic segment TBR (IAS-TBR) was designated as the aortic segment with the highest TBR. Result(s): There was no significant difference in aortic 18F-FDG PET/CT uptake between patients and controls (GLA-TBR: 1.46 [1.40-1.57] vs. 1.43 [1.32-1.70], respectively, p=0.422 and IAS-TBR: 1.60 [1.50-1.67] vs. 1.50 [1.42-1.61], respectively, p=0.155). There was a moderate correlation between aortic TBR values (both GLA and IAS) and time distance from admission to 18F-FDG PET-CT scan (Spearman's rho=-0.528, p=0.017 and Spearman's rho=-0.480, p=0.032, respectively), Figure 1. Patients who were scanned less than or equal to 60 days from admission (n=11) had significantly higher GLA-TBR values compared to patients that were examined more than 60 days post-admission (GLA-TBR: 1.53 [1.42-1.60] vs. 1.40 [1.33-1.45], respectively, p=0.016 and IAS-TBR: 1.64 [1.51-1.74] vs. 1.52 [1.46-1.60], respectively, p=0.038). There was a significant difference in IAS-TBR between patients scanned <=60 days and controls (1.64 [1.51-1.74] vs. 1.50 [1.41-1.61], p=0.036), Figure 2. Conclusion(s): This is the first study suggesting that aortic inflammation, as assessed by 18F-FDG PET/CT imaging, is increased in the early post-COVID phase in patients with severe or critical COVID-19 and largely resolves over time. Our findings may have important implications for the understanding of the course of the disease and for improving our preventive and therapeutic strategies.
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SESSION TITLE: Issues After COVID-19 Vaccination Case Posters SESSION TYPE: Case Report Posters PRESENTED ON: 10/19/2022 12:45 pm - 01:45 pm INTRODUCTION: Sarcoidosis and sarcoid-like reactions tend to be diagnoses of exclusion when evaluating patients with malignancy, and have a number of inciting causes. This is a unique case of a patient diagnosed with non-necrotizing granulomatous inflammation on biopsy of mediastinal lymph nodes and skin lesions after receiving SARS-CoV-2 vaccine, while also being on Temozolamide (TMZ). Biopsy-proven sarcoid has rarely been reported in the literature following SARS-CoV-2 vaccine or TMZ. CASE PRESENTATION: 66-year-old female with a history of prolactinoma complicated by recurrence and progression of disease despite surgery, radiation, and medical therapy, who started her first cycle of TMZ and received her first SARS-CoV-2 vaccine 9 days later. About 2 weeks later, she noted numerous painless "bumps” on her bilateral upper and lower extremities with erythema, without fevers, joint pains, or other symptoms. She underwent a positron emission tomography (PET) scan which demonstrated multiple hypermetabolic subcutaneous lesions, along with intensely hypermetabolic bilateral hilar lymphadenopathy. She underwent punch biopsy notable for sparse inflammation. She underwent her second SARS-CoV-2 vaccine and second cycle of TMZ. After 1 week, she noticed increased induration and erythema over her lesions, and held her TMZ. She underwent incisional biopsy of her thigh which demonstrated granulomatous panniculitis. She also underwent bronchoscopy with endobronchial ultrasound (EBUS) and transbronchial needle aspiration (TBNA) of her paratracheal and subcarinal lymph nodes, which demonstrated non-necrotizing granulomatous inflammation. Labs were only significant for ACE level of 60u/L (normal<40u/L). With a relative paucity of symptoms and no other obvious vital organ involvement, she was not treated, continued her TMZ without flares, and her symptoms self-resolved after opting out of the third SARS-CoV-2 vaccine. DISCUSSION: Sarcoid-like inflammatory reactions have rarely been reported in the literature following SARS-CoV-2 vaccine or TMZ. One case of panniculitis secondary to TMZ administration was reported that improved after discontinuation of TMZ [1]. Our patient continued TMZ therapy without further symptoms, which makes TMZ less likely as her inciting cause. Three cases of sarcoid-like reactions secondary to SARS-CoV-2 vaccine have been reported [2, 3] but two of these cases were diagnosed clinically as Löfgren syndrome without biopsy [3], making this case the second reported case of biopsy-proven de novo sarcoid reaction in the setting of SARS-CoV-2 vaccine. CONCLUSIONS: Sarcoid-like inflammatory reactions following SARS-CoV-2 vaccine have not been well-reported in the literature. This case, among the other limited cases reported, underscores the need to consider sarcoid on the differential of vaccine-related side effects, especially in those with bilateral hilar lymphadenopathy and cutaneous lesions. Reference #1: Virmani P., Chung E., Marchetti M. A. (2015). Cutaneous adverse drug reaction associated with oral temozolomide presenting as dermal and subcutaneous plaques and nodules. Jaad. Case. Rep. 1, 286–288. 10.1016/j.jdcr.2015.06.012 Reference #2: Bauckneht, M., Aloè, T., Tagliabue, E. et al. Beyond Covid-19 vaccination-associated pitfalls on [18F]Fluorodeoxyglucose (FDG) PET: a case of a concomitant sarcoidosis. Eur J Nucl Med Mol Imaging 48, 2661–2662 (2021). https://doi.org/10.1007/s00259-021-05360-w Reference #3: Rademacher JG, Tampe B, Korsten P. First Report of Two Cases of Löfgren's Syndrome after SARS-CoV-2 Vaccination-Coincidence or Causality? Vaccines (Basel). 2021 Nov 11;9(11):1313. doi: 10.3390/vaccines9111313. PMID: 34835244;PMCID: PMC8619392 DISCLOSURES: no disclosure on file for Alexander Geyer;No relevant relationships by Mustafa Jafri
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Background: Lymphoma is one of the most common primary malignancies of the hematopoietic system. Lymphoid neoplasms are classified into Hodgkin’s and Non-Hodgkin’s lymphoma. Non-Hodgkin lymphoma accounts for about 5% of all cases of malignancies, It is less predictable than Hodgkin lymphoma and more liable for extra-nodal spread. Males are slightly more affected than females with higher incidence in white population. B-cell lymphomas have higher incidence in adults while T-cell lymphomas have higher incidence in children. With many imaging modalities that can describe the morphological changes in lymph nodes, it’s almost exclusive for the PET/CT to describe the biological changes in those lymph nodes through their uptake of FDG which has a great value in determining whether those lymph nodes are affected or not, which in turn will play an important role in treatment & management plan. What gives PET/CT scan the upper hand is that it acts on the biological level of the cells which permit early discovering of the affected lymph nodes, much earlier than standard C.T or MRI scan.
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Introduction: We aimed to analyse the effect of coronavirus disease 2019 (COVID-19) vaccination on F-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging findings in cancer patients. Methods: A total of 165 oncology patients who underwent FDG PET/CT between 1 May 2021 and 30 September 2021 after their first or second COVID-19 vaccination with were included in this retrospective study. The occurrence and pattern of FDG uptake at the injection site (usually deltoid), ipsilateral axillary and other regional lymph nodes, were measured. Results: Overall, the incidence of FDG-avid ipsilateral regional nodal uptake was 26.7% (44/165), with a median maximal standardised uptake value of 3.2 (range, 1.7-13.8). Vaccine-associated hypermetabolic lymphadenopathy (VAHL) was found in 11.4% (5/44) of the subjects beyond 6 weeks after vaccination. VAHL was more common in patients receiving BioNTech-Fosun mRNA vaccine (compared with patients receiving the Sinovac CoronaVac inactivated vaccine), and in women (p < 0.05). Conclusion: VAHL is common and can be observed beyond 6 weeks after vaccination. It was seen more frequently in women and in patients receiving the mRNA-based vaccine. Proper vaccination history documentation, locating the vaccination site contralateral to the primary cancer, and appropriate scheduling of FDG PET/CT are advisable for correct image interpretation.
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Background-Aim: 18F-FDG PET/CT currently represents the nuclear medicine imaging procedure of choice for staging and posttreatment response assessment in patients with Hodgkin lymphoma (HL). It is well known that 18F-FDG also accumulates in sites of inflammation and infection. Here we report a case of a patient affected by lung HL and concomitant incidental COVID-19 interstitial pneumonia. Methods: The case refers to a 67 years old female patient affected by nodular sclerosing classical HL involving left axillary lymph nodes and both lungs. The patient came to our attention to perform wholebody 18F-FDG PET/CT at initial staging (scan 1), after two cycles of ABVD (scan 2) and at the end of treatment (scan 3). All 18F-FDG PET/CT examinations were performed according to standard acquisition protocols, starting approximately 60 min after i.v. injection of 3.7 MBq/kg of 18F-FDG. Results: At scan 1, 18F-FDG-PET/CT showed hypermetabolic left axillary lymph nodes and multiple disseminated avid lesions in both lungs. Scan 2 demonstrated complete metabolic response associated to almost complete resolution of axillary lymphadenopathy and lung lesions at CT scan. At the end of treatment, scan 3 showed hypermetabolic mediastinal lymph nodes and multiple areas of increased 18F-FDG uptake in both lungs, mostly in pulmonary regions other than those of the basal scan, and in correspondence of multiple ground-glass opacities and consolidations at CT. These findings were more suggestive for interstitial pneumonia than for HL residual disease;in addition, contrast-enhancement CT performed 1 week before scan 3, resulted completely negative. Given the ongoing SARS-CoV- 2 pandemic, the patient, although asymptomatic, was scheduled to perform nasopharyngeal molecular swab test for COVID-19;the test resulted positive, corroborating the hypothesis of early interstitial pneumonia. The patient was clinically monitored and 3 months later underwent a further 18F-FDG PET/CT scan which was negative, definitively confirming the absence of lymphomatous disease. Conclusions: In this patient affected by lung HL, an incidental early COVID-19 pneumonia was detected by 18F-FDG PET/CT. The comparison of basal and post-treatment PET/CT scans in combination with lung CT patterns have led to a correct assessment of chemotherapy response.
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Background-Aim: A 46 years old housewife patient with a bachelor's degree in Law contracted Covid-19 at the end of March 2021. She had a flu-like form with associated asthenia and drowsiness and no lack of sense of smell. It has been resolved in 25 days. Later, she developed progressive immediate memory loss, word-finding issues, motor and thinking slowing down. Methods: CT brain scan appeared as within the norm as well as liver enzymes, TSH, Vitamin B12, Folate and Rapid Plasma Reagine. Anti- ENA DNA ANA HIV TPO TG were negative too. In October, the patient had a further neuropsychological assessment that showed an overall picture characterized by partial orientation to space, working memory disorders, writing and comprehension (of complex tasks) issues, and immediate memory loss (possible sign both of attention span and concentration reduction). The auto-antibodies were assessed in November and they resulted negative. Moreover, the brain MRI scan and EEG (dated at the end of November) were both within the range. CSF neurodegenerative biomarkers and anti-neuronal antibodies appeared in the norm too. Results: Ultimately, in December 2021 she underwent an 18F-FDG PET brain scan and the SPM analysis showed an extensive hypometabolism in the bilateral frontal cortex and bilateral straight gyrus. Spared the cingulate cortex. Conclusions: The patient contracted Covid in March 2021. She developed neurological deterioration identified by FDG-PET. Negative autoantibodies and CSF biomarkers. PET scan was the only exam to define the brain damage in the patient above. Symmetrical bilateral frontal cortex and bilateral straight gyrus hypo-metabolism have been observed, the last one at the direct level of the olfactory bulb. In this area, in patients who died from Covid-19 it has been histologically demonstrated (data to be published) the presence of cellular inclusions named Corpore Amylacea. They would be a small hyaline mass that functions as a waste container that accumulates in the human brain in aging and in neurodegenerative and infectious processes. It is hypothesized to be that it can be involved in a sort of brain cleaning process1. Recently it has been described that they contain some neoepitopes that are recognized by natural IgMs, revealing a possible link between them and the natural immune system2. However, to now in our patient, the only diagnostic tool to evaluate the brain condition has been the 18F-FDG PET.
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Background-Aim: Vaccination is an established but uncommon cause of unilateral axillary lymphadenopathy. Early clinical experience with coronavirus disease (COVID-19) vaccination suggests that such vaccines cause a significantly higher incidence of lymphadenopathy detected on 18F-FDG PET/CT than other vaccines. Guidelines are needed to properly manage unilateral axillary lymphadenopathy in the era of COVID-19 vaccination and to avoid benign reactive node biopsies. The differential diagnosis for unilateral axillary lymphadenopathy is broad and includes benign and malignant etiologies: among the malignant causes, most cases are due to lymphoma or breast cancer. Methods: Shortly after the initiation of vaccination of frail cancer patients, a significant number of cases of unilateral axillary lymphadenopathy were incidentally detected in asymptomatic cancer patients who underwent 18F-FDG PET/CT for disease diagnosis or follow-up. Results: After deltoid vaccination, significant uptake of 18F-FDG can be observed in the axillary (level 1, 2 and 3), supraclavicular and cervical lymph nodes. The extent of FDG absorption varies with temporal proximity to vaccination, from intense immediately after administration to barely noticeable after a longer period of time (SUVmax range: 2.1-16.2). Also, after vaccination, lymph nodes may show variable morphology on CT, although they are usually normal or show only a slightly thickened cortex with retained fat hilum. In our department, we have added questions regarding the date and laterality of COVID-19 vaccine administration to our intake form prior to all PET/CT exams, to avoid misjudgment in cancer patients. Conclusions: We believe that isolated unilateral axillary lymphadenopathy detected on PET and associated with the ipsilateral vaccine arm is related to the COVID-19 vaccine, if within a few weeks of either dose. As data from clinical trials of the COVID-19 vaccine suggest that the first two FDA-approved vaccines are highly immunogenic, there is a higher percentage of patients who notice both local and systemic reactions than other vaccines. Careful management should avoid unnecessary biopsies of vaccine-related benign reactive lymphadenopathy. Vaccine ipsilateral axillary adenopathy of the arm should be considered as a potential reactive process that nuclear physicians should be familiar with. If a patient has known cancer with laterality, such as breast cancer, most melanomas, sarcoma of the extremities, lung cancer (particularly in the upper lobe), or head and neck cancer, the vaccine should be given in the arm. contralateral to avoid potentially confounding FDG uptake into lymph nodes on the cancer side. However, if active axillary lymph nodes are identified in the ipsilateral vaccinated arm, axillary ultrasound at 4 weeks is recommended.
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Background: Fever of unknown origin (FUO) is a challenging clinical problem in medicine that needs collaboration of various diagnostic techniques to establish the accurate diagnosis. We evaluated the diagnostic performance of 18F-FDG PET/CT in patients who presented themselves with FUO. Our study included 40 patients with FUO who underwent PET/CT examination and their results were compared to the results of laboratory, histopathological, microbiological investigations and/or response to therapy. Results: The final diagnosis included malignancy in 20 patients (50%), infectious causes in 7 patients (17.5%) and non-infectious inflammatory causes in 6 patients (15%). Fever resolved without diagnosis in 4 patients (10%), while no definite diagnosis was reached in 3 patients (7%). PET/CT successfully contributed to diagnosis of 35 out of 40 patients with diagnostic accuracy of 87.5%. The sensitivity, specificity, positive predictive value and negative predictive value of PET/CT in our study were 93.5%, 66.7%, 90.6% and 75%, respectively. Conclusion: PET/CT is a useful tool to investigate and diagnose the cause of FUO. It provides information that can guide the treatment strategy of the patients.
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Introduction: Epistaxis and gingival bleeding are among the most common presentation to the emergency department for patients with thrombocytopenia. Here, we present a case who was admitted to the emergency department with thrombocytopenia and was diagnosed with metastatic cancer of unknown primary origin. Case Report: A 26-year-old male patient was admitted to the emergency department with gingival bleeding and epistaxis. The body temperature was 38.3 °C. Petechial rash, ecchymosis or organomegaly was not detected on physical examination. Laboratory results revealed thrombocytopenia as 31 × 103 (159-388 × 103/μL). Although hemoglobin and leukocyte counts were normal, no band or precursor cell was observed in the patient's peripheral blood smear. There was no history of weight loss, night sweats, arthritis, malar rash, photosensitivity, contact with ticks, animals, or a COVID-19 patient. Serological tests performed for infections such as HIV, EBV, HCV, Crimean-Congo hemorrhagic fever were negative. Bone marrow biopsy was performed due to the unexplained cytopenia, reported as "signet ring cell metastatic adenocarcinoma". Gastrointestinal system endoscopy was performed to detect primary cancer. A biopsy was taken from the antrum and corpus revealed gastritis. An FDG PET-CT was revealed heterogeneously pathologically increased FDG attitude in all axial and appendicular bones. Despite all the modalities of diagnosis, the origin was not found and the patient was transferred to the oncology department for treatment with a diagnosis of cancer of unknown origin with bone marrow infiltration. Conclusion: Bone marrow metastases should be kept in mind in patients presenting with thrombocytopenia.
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Background: Human epidermal growth factor receptor 2 (HER2) status is an important predictive biomarker in breast cancer (BC). Tumor heterogeneity has been described, with changes in HER2 expression levels between lesions and over the disease course. HER2 expression is assessed on tissue biopsies, at primary diagnosis and in metastatic lesions. A whole-body imaging technique such as PET/CT could help understand expression levels in different lesions. A 68Ga-labeled single domain antibody (sdAb) targeting the HER2 receptor has been developed and proven safe (Keyaerts et al., 2016). Imaging is performed at 90 min post-injection (pi). We report results of a phase II trial to assess the repeatability of the technique in 20 patients and the correlation of tracer uptake with HER2 tissue expression of the lesions present at the time of imaging. Methods: Twenty patients (pts) with a locally advanced or metastatic BC with at least one lesion of minimum 12 mm were included. Pts were injected intravenously with a typical protein mass of 100 μ g and a radioactive dose ranging from 98-168 MBq 68GaNOTA-anti-HER2 sdAb. PET/CT images were Sobtained at 90 min pi. A second tracer injection followed by PET/CT was done with a maximal interval of 8 days. To assess repeatability, up to 5 lesions per pt were selected, with no more than 2 in a single organ. Peak Standard Uptake Values (SUVpeak) of the lesions were measured on both scans and compared with a t-test and Bland-Altman Plots. Images were compared to other available medical or imaging data and interpreted considering the subject's disease course. Serum and plasma samples were collected before injection and between 60 and 365 days pi and stored for future detection of anti-drug antibodies (ADA) and liquid biopsies analysis for the presence of HER2 amplification. Tissue samples were assessed by central labs using mass spectrometry, immunohistochemistry and in fluorescence situ hybridization. Results: Twenty women with BC (6 HER2+, 14 HER2-) with a mean age of 58.6 y (37-81) were included. Three pts were scanned only once (2 due to withdrawal of consent, 1 due to covid pandemic). Repeatability of the technique was visually scored as excellent. For quantification, 50 lesions were compared on both scans in 17 pts without significant differences between the two measurements (p=0.40). The repeatability coefficient (RC) was 38.2%. The mean absolute percentage difference (MAPD) was 13.6%, comparable to repeat values reported for 18F-FDG. In 3 out of 6 HER2-positive (HER2+) patients, lesions showed high uptake, even better visible than using 18F-FDG in 2 of them. In 2 HER2+ subjects with a negative scan, lesions were confirmed to be true negatives: one patient did not relapse from BC but had tuberculosis;the other was confirmed to have a radiopneumonitis after radiotherapy and no relapse. In 1 HER2+ patient, the uptake was unexpectedly low. However, the HER2 status was also not reconfirmed in the metastatic setting for this subject. In 1 HER2-negative patient, the tumor HER2 status was changed from negative to positive based on a subsequent image-guided biopsy performed in this study. High tracer uptake was also seen in many of the patients presenting with HER2-low BC (IHC 1+ or 2+), indicating the potential of the tracer to detect low-level HER2 expression. Additional correlation to centrally performed tissue and blood analysis is ongoing. Conclusion: 68GaNOTA-Anti-HER2 PET/CT shows high uptake in HER2-expressing BC lesions but also in HER2-low lesions. The technique shows good repeatability and, in some cases, even better sensitivity than 18F-FDG PET/CT. Specificity was confirmed in relapse-free lesions such as tuberculosis and radiopneumonitis. Its sensitivity makes it a promising technique to assess HER2+ and HER2-low lesions in BC patients.
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Introduction: Multisystem Inflammatory Syndrome in Children (MISC) is an emerging clinical condition, similar to the hyperinflammatory response seen in adults with COVID-191. To date, little is known about the natural history of the disease and the long-term monitoring of MIS-C patients. Positron emission tomography PET/MRI is actually used to identify active inflammatory or neoplastic sites using [18F]fluorodeoxyglucose (FDG) due to the high glycolytic metabolism of inflammatory/neoplastic tissues2. Therefore, it could be indicated to evaluate and monitor the inflammatory disease state2. Objectives: To describe the PET/MRI findings for the evaluation of the minimal residual disease in a cohort of patients with MIS-C. Methods: Consecutive patients with MIS-C underwent a whole body FDG PET/MRI by 2 weeks, when possible, and at 6 weeks after the onset of fever. Each patient, after a 36 hours of fasting and high-fat low carbohydrate (<5g/day) diet preparation, was scanned using 3 MBq/kg FDG to minimize the radiation exposure. Clinical and laboratory data were also collected at onset and during follow up. Results: Ten patients (7M, 3F), mean age 10.2 years (range 5.4-17.7), all with positive clinical and/or serological evidence of previous SARS-COV2 infection, entered the study. All presented high degree fever, gastrointestinal symptoms and rash. Conjunctivitis and cardiovascular involvement, as hypotension, significant myocardial dysfunction and increased myocardiolysis markers, were also present in half of them. Only one patient needed intensive care support for five days. Systemic inflammatory and prothrombotic markers were elevated in all patients on admission (mean CRP 166.3 mg/L;procalcitonin 11.8 ug/L;D-dimer 2348 ug/L, ferritin 1135 ng/L). All patients were treated, 4.5 (± 1.5) days from fever onset with pulse IVIG (2 g/ kg) and IV methyprednisone (MPDN 2 mg/kg/day, max 80 mg) for 2 weeks then with oral PDN tapered down to 0 in further 4 weeks. PET/MRI was performed 13.3 days (± 1.5) after fever onset in three patients and 48 days (± 10.6) in 8. During the acute phase, all patients showed pelvic effusion and edema of the abdominal wall tissues at the total body MRI, not seen in patients during the late phase. Lymph node involvement was present in 81% of MRI findings. The cervical district appeared to be the most involved one as compared to the thoracic, mesenteric and retroperitoneal ones (72% vs 45, 36 and 45% respectively). However, a residual mesenteric lymphadenopathy was exclusive to the late phase (5/8 patients). Conclusion: PET/MRI confirms the good metabolic response to treatment in patients with MIS-C. The abdominal region is more intensively involved in the early stage of the disease, likely related to the hyperinflammatory state. A slow normalization through the lymph node compartment is present in the late stage. PET/MRI is a highly sensitive and specific tool for assessing minimal residual disease in MIS-C and should be indicated for patients with incomplete clinical response to treatment.
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OBJECTIVES: To assess the frequency, intensity, and clinical impact of [18F]FDG-avidity of axillary lymph nodes after vaccination with COVID-19 vaccines BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) in patients referred for oncological FDG PET/CT. METHODS: One hundred forty patients referred for FDG PET/CT during February and March 2021 after first or second vaccination with Pfizer-BioNTech or Moderna were retrospectively included. FDG-avidity of ipsilateral axillary lymph nodes was measured and compared. Assuming no knowledge of prior vaccination, metastatic risk was analyzed by two readers and the clinical impact was evaluated. RESULTS: FDG PET/CT showed FDG-avid lymph nodes ipsilateral to the vaccine injection in 75/140 (54%) patients with a mean SUVmax of 5.1 (range 2.0 - 17.3). FDG-avid lymph nodes were more frequent in patients vaccinated with Moderna than Pfizer-BioNTech (36/50 [72%] vs. 39/90 [43%] cases, p < 0.001). Metastatic risk of unilateral FDG-avid axillary lymph nodes was rated unlikely in 52/140 (37%), potential in 15/140 (11%), and likely in 8/140 (6%) cases. Clinical management was affected in 17/140 (12%) cases. CONCLUSIONS: FDG-avid axillary lymph nodes are common after COVID-19 vaccination. The avidity of lymph nodes is more frequent in Moderna compared to that in Pfizer-BioNTech vaccines. To avoid relatively frequent clinical dilemmas, we recommend carefully taking the history for prior vaccination in patients undergoing FDG PET/CT and administering the vaccine contralateral to primary cancer. KEY POINTS: ⢠PET/CT showed FDG-avid axillary lymph nodes ipsilateral to the vaccine injection site in 54% of 140 oncological patients after COVID-19 vaccination. ⢠FDG-avid lymphadenopathy was observed significantly more frequently in Moderna compared to patients receiving Pfizer-BioNTech-vaccines. ⢠Patients should be screened for prior COVID-19 vaccination before undergoing PET/CT to enable individually tailored recommendations for clinical management.