Axillary lymph node accumulation on FDG-PET/CT after influenza vaccination

Vaccine-associated axillary lymphadenopathy with a focus on COVID-19 vaccines

Axillary lymphadenopathy (LA) after COVID-19 vaccination is now known to be a common side effect. In these cases, malignancy cannot always be excluded on the basis of morphological imaging criteria.Narrative review for decision-making regarding control and follow-up intervals for axillary LA according to currently published research. This article provides a practical overview of the management of vaccine-associated LA using image examples and a flowchart and provides recommendations for follow-up intervals. A particular focus is on patients presenting for diagnostic breast imaging. The diagnostic criteria for pathological lymph nodes (LN) are explained.Axillary LA is a common adverse effect after COVID-19 vaccination (0.3-53%). The average duration of LA is more than 100 days. LA is also known to occur after other vaccinations, such as the seasonal influenza vaccine. Systematic studies on this topic are missing. Other causes of LA after vaccination (infections, autoimmune diseases, malignancies) should be considered for the differential diagnosis. If the LA persists for more than 3 months after COVID-19 vaccination, a primarily sonographic follow-up examination is recommended after another 3 months. A minimally invasive biopsy of the LA is recommended if a clinically suspicious LN persists or progresses. In the case of histologically confirmed breast cancer, a core biopsy without a follow-up interval is recommended regardless of the vaccination, as treatment appropriate to the stage should not be influenced by follow-up intervals. For follow-up after breast cancer, the procedure depends on the duration of the LA and the woman's individual risk of recurrence.Vaccination history should be well documented and taken into account when evaluating suspicious LN. Biopsy of abnormal, persistent, or progressive LNs is recommended. Preoperative staging of breast cancer should not be delayed by follow-up. The risk of false-positive findings is accepted, and the suspicious LNs are histologically examined in a minimally invasive procedure. · The vaccination history must be documented (vaccine, date, place of application).. · If axillary LA persists for more than 3 months after vaccination, a sonographic follow-up examination is recommended after 3 months.. · Enlarged LNs that are persistent, progressive in size, or are suspicious on control sonography should be biopsied.. · Suspicious LNs should be clarified before starting oncological therapy, irrespective of the vaccination status, according to the guidelines and without delaying therapy.. · Wilpert C, Wenkel E, Baltzer PA et al. Vaccine-associated axillary lymphadenopathy with a focus on COVID-19 vaccines. Fortschr Röntgenstr 2024; DOI 10.1055/a-2328-7536.

Examination of iatrogenic FDG accumulation after COVID-19 vaccination

PURPOSE

This study aimed to investigate the frequency of COVID-19 vaccine-induced reactive change and potential factors including blood type correlated with increased FDG uptake on positron emission tomography (PET)/computed tomography (CT).

MATERIALS AND METHODS

We evaluated 284 patients who underwent PET/CT between June and September 2021 and had a known history of COVID-19 vaccination. Information on the injection site, vaccine type, and adverse reactions was obtained. We visually assessed the presence or absence of accumulation in the axillary and supraclavicular lymph nodes and the deltoid muscles. We measured the maximum standardized uptake value (SUVmax) using semi-quantitative analysis.

RESULTS

Our study included 158 males and 126 females aged 16-94. The median time between vaccination and PET/CT was 9 and 42 days for patients who had received their first and second doses, respectively. We observed axillary lymph node accumulation, supraclavicular lymph node accumulation, and deltoid muscle accumulation in 98 (SUVmax 1.07-25.1), nine (SUVmax 2.28-14.5), and 33 cases (SUVmax 0.93-7.42), respectively. In cases with axillary lymph node (P = 0.0057) or deltoid muscle (P = 0.047) accumulation, the shorter the time since vaccination, the higher the FDG accumulation. Patients with axillary lymph node accumulation were significantly younger (P < 0.0001) and had a significantly higher frequency of adverse reactions such as fever (P < 0.0001) and myalgia (P = 0.002). No significant relationship was observed between blood type and the frequency of FDG accumulation. Logistic regression analysis also showed that age, gender, days since vaccination, and adverse reactions such as fever and myalgia were important factors for axillary lymph node accumulation.

CONCLUSION

Our study found that FDG accumulation in the axillary lymph nodes and deltoid muscle was higher within a shorter time after vaccination, and axillary lymph node accumulation was higher in young patients, females, and those with adverse reactions of fever and myalgia. No significant relationship was observed between blood type and the frequency of FDG accumulation. Confirming the vaccination status, time since vaccination, and the presence of adverse reactions before PET may reduce false positives.

Incidence, Timing, and Long-Term Outcomes of COVID-19 Vaccine-Related Lymphadenopathy on Screening Mammography

OBJECTIVE

To determine the incidence, timing, and long-term outcomes of unilateral axillary lymphadenopathy ipsilateral to vaccine site (UIAL) on screening mammography after COVID-19 vaccination.

METHODS

This retrospective, multisite study included consecutive patients undergoing screening mammography February 8, 2021, to January 31, 2022, with at least 1 year of follow-up. UIAL was typically considered benign (BI-RADS 1 or 2) in the setting of recent (≤6 weeks) vaccination or BI-RADS 0 (ultrasound recommended) when accompanied by a breast finding or identified >6 weeks postvaccination. Vaccination status and manufacturer were obtained from regional registries. Lymphadenopathy rates in vaccinated patients with and without UIAL were compared using Pearson's χ2 test.

RESULTS

There were 44,473 female patients (mean age 60.4 ± 11.4 years) who underwent screening mammography at five sites, and 40,029 (90.0%) received at least one vaccine dose. Ninety-four (0.2%) presented with UIAL, 1 to 191 days postvaccination (median 13.5 [interquartile range: 5.0-31.0]). Incidence declined from 2.1% to 0.9% to ≤0.5% after 1, 2, and 3 weeks and persisted up to 36 weeks (P < .001). UIAL did not vary across manufacturer (P = .15). Of 94, 77 (81.9%) were BI-RADS 1 or 2 at screening. None were diagnosed with malignancy at 1-year follow-up. Seventeen (18.1%) were BI-RADS 0 at screening. At diagnostic workup, 13 (76.5%) were BI-RADS 1 or 2, 2 (11.8%) were BI-RADS 3, and 2 (11.8%) were BI-RADS 4. Both BI-RADS 4 patients had malignant status and ipsilateral breast malignancies. Of BI-RADS 3 patients, at follow-up, one was biopsied yielding benign etiology, and one was downgraded to BI-RADS 2.

DISCUSSION

Isolated UIAL on screening mammography performed within 6 months of COVID-19 vaccination can be safely assessed as benign.

The systemic impact of different COVID-19 vaccines in 2-[18F] FDG-PET/CT

Austria started its COVID-19-vaccination program in December 2020 with three different vaccines. As the vaccination program continues, we encountered increased 2-[18F] FDG-activity not only in axillary lymph nodes ipsilateral to the injection site but also in other organs. The aim of this retrospective study is to present results of the metabolic activity of ipsilateral axillary lymph nodes, liver, blood pool, spleen, and bone marrow after three different vaccines. To our knowledge, this is the first study to examine systemic response changes in relation to time after COVID-19 vaccination using three different vaccines. The collected data of 220 eligible vaccinated patients (127 with BioNTech/Pfizer BNT162b2, 61 with Moderna, and 32 with AstraZeneca) examined with 2-[18F] FDG-PET/CT were enrolled. The PET/CT examinations were evaluated from day 1 to day 135 (SD: 23.2, median: 26) after different vaccinations. Seventy-one out of these 220 patients underwent a pre-vaccination 2-[18F] FDG -PET/CT. SUVmax of axillary node(s), and blood pool, liver, spleen, and bone marrow as reference organs were calculated. The ratio of SUVmax activity of axillary lymph node to reference organs was also compared in all patients. The tracer activity dynamics were investigated in three different vaccines. After BioNTech/Pfizer vaccination 2-[18F] FDG activity in axillary lymph nodes shows a steady decrease in all patients. Ten days after vaccination the 2-[18F] FDG uptake was at its highest activity. Seventy days after vaccination, tracer activity is not different from the background activity of 2-[18F] FDG in the axillary region. This result also applies to other two vaccines; however, in the 4th week after Moderna vaccination SUVmax in lymph nodes showed the highest peak of tracer activity. With AstraZeneca the highest activity was at the earlier days. There was no significant statistical difference of SUVmax of lymph nodes or its ratios to other reference organs between three groups of vaccines. SUVmax in lymph nodes was statistically significant lower than SUVmax in the liver, spleen, and bone marrow with p-values of < 0.001, 0.044, and 0.001, respectively. In the group of 71 patients with a pre-vaccination PET/CT examination, the median SUVmax of lymph nodes increased significantly after vaccination from 0.82 (IQR 0.59-1.38) to 1.80 (IQR 1.07-3.89)(p < 0.001). In contrast median tracer activity in the liver decreased from 3.37 (IQR 2.83-3.91) to 3.11 (2.56-3.70) (p = 0.032). There was no significant change of tracer activity after vaccination in other reference regions (mediastinum, spleen, and bone marrow). In this group of 71 patients, there was also no significant difference in tracer activity in different types of vaccines. Local site and ipsilateral axillary lymph node activity in 2-[18F] FDG PET/CT after COVID19-vaccination is suggested in many studies. The main challenge is recognizing the changes in lymph nodes during time after vaccination to minimize false interpretation, foremost in patients with oncological diagnoses. Moreover, different vaccines cause different system metabolic changes. The knowledge of vaccine type, the time interval between vaccination and PET/CT scan is essential, especially in therapy evaluation.

Comparison of post-COVID-19 vaccination hypermetabolic lymphadenopathy on 18F-fluorodeoxyglucose PET/CT between virus-vector vaccine and mRNA vaccine

PURPOSE

We compared hypermetabolic lymphadenopathy (HLN) on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after virus-vector and mRNA vaccines for coronavirus disease 2019 (COVID-19).

METHODS

This retrospective study included 573 participants who underwent FDG PET/CT after receiving a virus-vector vaccine (ChAdOx1, AstraZeneca [AZ] group) or an mRNA vaccine (mRNA-1273, Moderna [M] group) from July 2021 to October 2021. The incidence and avidity of HLN were evaluated and correlated with clinical features and vaccine type. The final analysis was conducted with 263 participants in the AZ group and 310 participants in the M group.

RESULTS

The HLN incidence was significantly lower in the AZ group than in the M group (38/263 [14%] vs. 74/310 [24%], p = 0.006). The FDG avidity of HLN was comparable between the two groups. The HLN incidence in both groups was significantly higher within 4 weeks after the vaccination compared with more than 4 weeks. The HLN incidence within 4 weeks of the vaccination was significantly higher in the M group than in the AZ group (p = 0.008), whereas a difference in HLN incidence between the two groups was not observed after the same duration (p = 0.11).

CONCLUSIONS

The mRNA mRNA-1273 COVID-19 vaccine was found to be associated with higher glucose hypermetabolism in regional lymph nodes within the first 4 weeks compared with the virus-vector vaccine, as indicated by the presence of HLN on FDG PET/CT. The degree of glucose hypermetabolism was comparable between the two vaccines.

Prediction of effective humoral response to SARS-CoV-2 vaccines in healthy subjects by cortical thickness of post-vaccination reactive lymphadenopathy

PURPOSE

To study the association between ultrasound cortical thickness in reactive post-vaccination lymph nodes and the elicited humoral response and to evaluate the performance of cortical thickness as a predictor of vaccine effectiveness in patients with and without a previous history of COVID-19 infection.

METHODS

A total of 156 healthy volunteers were recruited and followed prospectively after receiving two COVID-19 vaccination doses using different protocols. Within a week after receiving the second dose, an axillary ultrasound of the ipsilateral vaccinated arm was performed, and serial post-vaccination serologic tests (PVST) were collected. Maximum cortical thickness was chosen as a nodal feature to analyze association with humoral immunity. Total antibodies quantified during consecutive PVST in previously-infected patients and in coronavirus-naïve volunteers were compared (Mann-Whitney U test). The association between hyperplastic-reactive lymph nodes and effective humoral response was studied (odds ratio). The performance of cortical thickness in detecting vaccination effectiveness was evaluated (area under the ROC curve).

RESULTS

Significantly higher values for total antibodies were observed in volunteers with a previous history of COVID-19 infection (p < 0.001). The odds ratio associating immunized coronavirus-naïve volunteers after 90 and 180 days of the second dose with a cortical thickness ≥ 3 mm was statistically significant (95% CI 1.52-6.97 and 95% CI 1.47-7.29, respectively). The best AUC result was obtained comparing antibody secretion of coronavirus-naïve volunteers at 180 days (0.738).

CONCLUSIONS

Ultrasound cortical thickness of reactive lymph nodes in coronavirus-naïve patients may reflect antibody production and a long-term effective humoral response elicited by vaccination.

CLINICAL RELEVANCE STATEMENT

In coronavirus-naïve patients, ultrasound cortical thickness of post-vaccination reactive lymphadenopathy shows a positive association with protective antibody titers against SARS-CoV-2, especially in the long term, providing new insights into previous publications.

KEY POINTS

• Hyperplastic lymphadenopathy was frequently observed after COVID-19 vaccination. • Ultrasound cortical thickness of reactive post-vaccine lymph nodes may reflect a long-term effective humoral response in coronavirus-naïve patients.

Imaging of COVID-19 Vaccine-Related Axillary Lymphadenopathy: Initial Outcomes Based on US Features of Axillary Lymph Nodes

OBJECTIVE

The purpose of this study is to describe the imaging characteristics and outcomes of COVID-19 vaccine-related axillary adenopathy and subsequent follow-up.

METHODS

This was an IRB-approved, retrospective study of patients with imaging evidence of axillary lymphadenopathy who had received at least one dose of a COVID-19 vaccine and presented between January 1, 2021, and February 28, 2021. Sonographic cortical thickness and morphology was evaluated. A mixed effects model was used to model lymph node cortical thickness decrease over time.

RESULTS

A total of 57 women were identified with lymphadenopathy and a COVID vaccination during the study period with 51 (89.5%) women completing imaging surveillance or undergoing tissue sampling of a lymph node. Three women (5.9%) were diagnosed with metastatic breast cancer to an axillary node. There was a statistically significant correlation with cortical thickness at initial US evaluation and malignancy (7.7 mm [SD ± 0.6 mm] for metastatic nodes and 5 mm [SD ± 2 mm] for benign nodes, P = 0.02). Suspicious morphological features (effacement of fatty hilum, P = 0.02) also correlated with malignancy. Time to resolution of lymphadenopathy can be prolonged with estimated half-life of the rate of decrease in cortical thickness modeled at 77 days (95% CI, 59-112 days). Diffuse, smooth cortical thickening over 3 mm was the most common lymph node morphology.

CONCLUSION

Malignant lymph node morphology and cortical thickness best predicted malignancy. Benign hyperplastic lymph nodes were the most common morphology observed after COVID-19 vaccination. Lymphadenopathy after vaccination is slow to resolve.

Immune Response Related to Lymphadenopathy Post COVID-19 Vaccination

Mass vaccination against coronavirus disease 2019 (COVID-19) is a global health strategy to control the COVID-19 pandemic. With the increasing number of vaccinations, COVID-19 vaccine-associated lymphadenopathy (C19-VAL) has been frequently reported. Current findings emphasize the characteristics of C19-VAL. The mechanism of C19-VAL is complicated to explore. Accumulated reports separately show that C19-VAL incidence is associated with receiver age and gender, reactive change within lymph nodes (LN), etc. We constructed a systematic review to evaluate the associated elements of C19-VAL and provide the mechanism of C19-VAL. Articles were searched from PubMed, Web of Science and EMBASE by using the processing of PRISMA. The search terms included combinations of the COVID-19 vaccine, COVID-19 vaccination and lymphadenopathy. Finally, sixty-two articles have been included in this study. Our results show that days post-vaccination and B cell germinal center response are negatively correlated with C19-VAL incidence. The reactive change within LN is highly related to C19-VAL development. The study results suggested that strong vaccine immune response may contribute to the C19-VAL development and perhaps through the B cell germinal center response post vaccination. From the perspective of imaging interpretation, it is important to carefully distinguish reactive lymph nodes from metastatic lymph node enlargement through medical history collection or evaluation, especially in patients with underlying malignancy.

MRI/PET multimodal imaging of the innate immune response in skeletal muscle and draining lymph node post vaccination in rats

The goal of this study was to utilize a multimodal magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging approach to assess the local innate immune response in skeletal muscle and draining lymph node following vaccination in rats using two different vaccine platforms (AS01 adjuvanted protein and lipid nanoparticle (LNP) encapsulated Self-Amplifying mRNA (SAM)). MRI and ¹⁸FDG PET imaging were performed temporally at baseline, 4, 24, 48, and 72 hr post Prime and Prime-Boost vaccination in hindlimb with Cytomegalovirus (CMV) gB and pentamer proteins formulated with AS01, LNP encapsulated CMV gB protein-encoding SAM (CMV SAM), AS01 or with LNP carrier controls. Both CMV AS01 and CMV SAM resulted in a rapid MRI and PET signal enhancement in hindlimb muscles and draining popliteal lymph node reflecting innate and possibly adaptive immune response. MRI signal enhancement and total ¹⁸FDG uptake observed in the hindlimb was greater in the CMV SAM vs CMV AS01 group (↑2.3 - 4.3-fold in AUC) and the MRI signal enhancement peak and duration were temporally shifted right in the CMV SAM group following both Prime and Prime-Boost administration. While cytokine profiles were similar among groups, there was good temporal correlation only between IL-6, IL-13, and MRI/PET endpoints. Imaging mass cytometry was performed on lymph node sections at 72 hr post Prime and Prime-Boost vaccination to characterize the innate and adaptive immune cell signatures. Cell proximity analysis indicated that each follicular dendritic cell interacted with more follicular B cells in the CMV AS01 than in the CMV SAM group, supporting the stronger humoral immune response observed in the CMV AS01 group. A strong correlation between lymph node MRI T2 value and nearest-neighbor analysis of follicular dendritic cell and follicular B cells was observed (r=0.808, P<0.01). These data suggest that spatiotemporal imaging data together with AI/ML approaches may help establish whether in vivo imaging biomarkers can predict local and systemic immune responses following vaccination.

Role of [18F] FDG PET-CT in detection of COVID-19 vaccine-associated hypermetabolic lymphadenopathy (VAHL) in lymphoma patients: with serologic testing correlation

Background

COVID-19 vaccination of the population has a great importance, especially in oncological patients. The high incidence of vaccine-associated hypermetabolic lymphadenopathy (VAHL) makes a difficulty in the diagnosis of PET-CT of oncological patients. They should be vaccinated in the side opposite to the expected malignant LNs to avoid unnecessary biopsy and change in therapy. The aim of this study was to assess the role of PET-CT in detection of VAHL after the 2nd dose of Pfizer-BioNTech vaccine in lymphoma patients and compare the incidence of VAHL among lymphoma patients treated with B cell depletion therapy during the 6 months prior to vaccination and those treated > 6 months before vaccination.

Results

This study comprised 120 lymphoma patients, referred for FDG PET/CT 1–3 weeks after the 2nd dose of Pfizer-BioNTech COVID-19 vaccine. Hypermetabolic LNs were identified in 55%. The incidence of VAHL in lymphoma patients treated with anti-CD20 antibody rituximab during the 6 months prior to vaccination (9%) was significantly lower compared with other lymphoma patients treated with anti-CD20 antibody rituximab > 6 months before vaccination (91%). The incidence and grades of VAHL are significantly high within the 1st week after the 2nd dose of Pfizer-BioNTech vaccine in patients younger than 60 years of age. Only 7 of 37 patients with negative serology had VAHL on PET-CT, whereas 10 of 26 patients with decreased anti-spike titers and 49 of 57 patients with increased anti-spike titers had VAHL on PET-CT.

Conclusions

VAHL makes challenges in the interpretation of FDG PET/CT in oncology patients. Accurate data collection, regarding the time and site of COVID vaccination, is important to help radiologists in identifying the cause of abnormal nodal FDG uptake. We suggest to schedule FDG PET-CT for lymphoma patients at least 3 weeks after the 2nd dose of Pfizer-BioNTech vaccine.

FDG-PET findings associated with various medical procedures and treatments

[¹⁸F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-established modality with high sensitivity for the diagnosis and staging of oncologic patients. FDG is taken up by the glucose transporter of the cell membrane and becomes trapped within the cell. In addition to malignant neoplasms, active inflammatory lesions and some kinds of benign tumors also accumulate FDG. Moreover, the degree of uptake into normal organs and tissues depends on various physiological conditions, which is affected by various medical procedures, treatments, and drugs. To avoid misleading interpretations, it is important to recognize possible situations of unexpected abnormal accumulation that mimic tumor lesions. In this review, we present various FDG findings associated with surgical or medical procedures and treatments. Some findings reflect the expected physiological reaction to treatment, and some show inflammation due to prior procedures. Occasionally, FDG-PET visualizes other disorders that are unrelated to the malignancy, which may be associated with the adverse effects of certain drugs that the patient is taking. Careful review of medical records and detailed interviews of patients are thus necessary.

Hypermetabolic Ipsilateral Supraclavicular and Axillary Lymphadenopathy: Optimal Time Point for Performing an 18F-FDG PET/CT after COVID-19 Vaccination

Background: We aimed to evaluate the incidence of severe acute respiratory syndrome coronavirus type-2 (SARS-CoV2) vaccine-related hypermetabolic lymphadenopathy (HLA) and evaluate which time point produces the least number of false-positive findings in an 18F-2-Fluor-2-desoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT). Methods: For this retrospective, multi-center imaging study, patients with any form of SARS-CoV2 vaccination prior to an 18F-FDG-PET/CT were included between January 2021 and December 2021. Patients were divided into six groups according to the time point of vaccination prior to their 18F-FDG-PET/CT imaging, e.g., group one (0−6 days) and group six (35−80 days). As the reference standards, the SUVmax of the mediastinal blood pool (MBP) and the SUVmax contralateral reference lymph node (RL) were determined. (A) The absolute SUVmax of HLA, (B) the ratio of SUVmaxHLA/SUVmax mediastinal blood pool (rHLA/MBP), (C) the ratio SUVmax HLA vs. SUVmax contralateral reference lymph node (rHLA/RL), (D) and the incidence of HLA defined as rHLA/MBP > 1.5 were assessed. Results: Group one (days 0−6) showed the highest incidence of HLA 16/23 (70%) and rHLA/MBP (2.58 ± 2.1). All three parameters for HLA reduced statistically significantly in the comparison of Groups 1−3 (days 0−20) versus Groups 4−6 (days 21−80) (p-values < 0.001). Conclusions: If feasible, an FDG PET should be postponed by at least 3 weeks after SARS-CoV2 vaccination, especially if an accurate evaluation of axillary status is required.

Cancer Patients and the COVID-19 Vaccines: Considerations and Challenges

Few guidelines exist for COVID-19 vaccination amongst cancer patients, fostering uncertainty regarding the immunogenicity, safety, and effects of cancer therapies on vaccination, which this review aims to address. A literature review was conducted to include the latest articles covering the immunogenicity and safety of COVID-19 vaccination in patients with solid and hematologic cancers receiving various treatments. Lower seropositivity following vaccination was associated with malignancy (compared to the general population), and hematologic malignancy (compared to solid cancers). Patients receiving active cancer therapy (unspecified), chemotherapy, radiotherapy, and immunosuppressants generally demonstrated lower seropositivity compared to healthy controls; though checkpoint inhibition, endocrine therapy, and cyclin dependent kinase inhibition did not appear to affect seropositivity. Vaccination appeared safe and well-tolerated in patients with current or past cancer and those undergoing treatment. Adverse events were comparable to the general population, but inflammatory lymphadenopathy following vaccination was commonly reported and may be mistaken for malignant etiology. Additionally, radiation recall phenomenon was sporadically reported in patients who had received radiotherapy. Overall, while seropositivity rates were decreased, cancer patients showed capacity to generate safe and effective immune responses to COVID-19 vaccination, thus vaccination should be encouraged and hesitancy should be addressed in this population.

Axillary lymph node imaging in mRNA, vector-based, and mix-and-match COVID-19 vaccine recipients: ultrasound features

OBJECTIVES

To assess ultrasound characteristics of ipsilateral axillary lymph nodes after two doses of four different COVID-19 vaccination protocols, to determine whether these parameters differed with age, and to describe how they changed on follow-up imaging.

METHODS

A total of 247 volunteer employees from our center who had received two doses of COVID-19 vaccination were recruited and followed prospectively. Axillary ultrasound of the ipsilateral vaccinated arm was performed the week after receiving the second dose to analyze lymph node features (number, long-axis, cortical thickness, morphology, and vascular imaging). Axillary lymphadenopathy resulting from four vaccination protocols-mRNA (BNT162b2, mRNA-1273), ChAdOx1-S, and mix-and-match-was compared. Analysis was conducted using the Kruskal-Wallis test and post hoc analysis with Bonferroni corrections. Nodal reactogenicity was evaluated for two age groups: young (< 45 years old) and middle-aged ( ≥ 45 years old). All parameters were compared between both groups using an unpaired-sample Student t test. A p value < 0.05 was considered statistically significant.

RESULTS

Significantly higher values for total number of visible nodes, cortical thickness, Bedi's classification (p < 0.001), and vascularity (p < 0.05) were observed in mRNA vaccine recipients compared to full ChAdOx1-S protocol recipients. Moreover, mix-and-match protocol recipients showed greater nodal cortical thickness and higher Bedi's classification than full ChAdOx1-S recipients (p < 0.001). Analyses between age groups revealed greater cortical thickness, Bedi's classification, and color Doppler signal in younger patients (p < 0.05).

CONCLUSIONS

Nodal parameters of Bedi's classification and cortical thickness were more often increased in mRNA and mix-and-match vaccine recipients when compared to ChAdOx1-S vaccine alone, especially in younger patients.

KEY POINTS

• Hyperplastic lymphadenopathy was observed more frequently in mRNA and mix-and-match vaccine protocols compared to full vector-based vaccination. • Higher values for cortical thickness, Bedi's classification, and color Doppler signal parameters were identified in younger patients. • Observed lymph node findings normalized in greater than 80% of patients by the third month following vaccination.

Limiting Screening Mammography Recalls for Vaccine-Induced Adenopathy, a Single Institution Experience

RATIONALE AND OBJECTIVES

Reported incidence of vaccine-induced adenopathy varies widely, with higher estimates in early reports and small series. Objective was to evaluate a large sample of vaccinated patients undergoing screening mammography, to determine callback rates associated with vaccine-induced adenopathy and their outcomes.

MATERIALS AND METHODS

Single-institution retrospective review of patients who received at least 1 dose of a COVID-19 vaccine prior to presentation for screening mammography from January 15 through May 31, 2021. Patient-related vaccination information (dose, brand, arm, date) was obtained by mammography technologists and available for interpreting radiologists. Patients recalled for axillary adenopathy were included; other causes for recall were excluded. Follow-up imaging and outcomes were tracked. Wilcoxon rank-sum test, Fisher exact test, multivariable logistic regression modeling, and receiver operating characteristic curve analyses were utilized. All tests were two-sided; p < 0.05 considered statistically significant.

RESULTS

Total of 2304 vaccinated patients underwent screening mammography; 24 (1.0%) recalled for ipsilateral adenopathy. There was no significant difference in presence of adenopathy associated with patient age, dose, or brand of vaccine. Presence of adenopathy significantly decreased as days from vaccination increased (p < 0.001). Receiver operating characteristic curve suggested 28.5 days as the best cutoff point to distinguish presence or absence of adenopathy on mammogram. Of 24 callbacks, 13 (54.2%) had benign results, 2 (8.3%) are still undergoing surveillance, and 9 (37.5%) are overdue for subsequent follow-ups. No cases resulted in biopsy or malignancy.

CONCLUSION

Low recall rates related to vaccine-induced adenopathy are achievable and can limit unnecessary workups, improve access, and promote flexible timing of vaccinations and screening exams.

Lymphadenopathy subsequent to Covishield (ChAdOx1 nCoV-19) Corona virus vaccine: ultrasound findings and clinical implications

Introduction

Post anti-COVID-19 vaccine lymphadenopathies have been recently described in literature, from different parts of the world. Although there have been studies on lymphadenopathy following mRNA vaccines, there is a paucity of studies on lymphadenopathy following inactivated viral vaccines, such as Covishield.

Aim

In this study, we explored lymphadenopathy subsequent to Covishield vaccine in terms of its various ultrasound parameters in the Indian population.

Methods

This hospital-based longitudinal study was conducted among 50 adult beneficiaries of Covishield vaccine. Sociodemographic details and relevant clinical history were recorded using a semi-structured performa. Detailed ultrasound (USG) examination of the bilateral axillae was done on the day of vaccination and after 6-12 days post vaccination. Vaccine beneficiaries were evaluated for the presence of any vaccine-associated lymphadenopathy and described the presence, number, size, morphology, cortical thickness, and presence or absence of echogenic hilum.

Results

Out of total (63) lymph nodes evaluated sonologically, majority (80.9%) of lymph nodes showed the features of benign lymphadenopathy. However, 12.6% (8/63) lymph nodes showed diffusely thickened cortex with preserved central echogenic hilum, 4.76% (3/63) lymph nodes showed eccentric cortical thickness with preserved hilar pattern, while only one lymph node showed diffuse cortical thickening with loss of central echogenic hilum.

Conclusion

With an increase in vaccination coverage, clinicians are likely to confront increasing cases of vaccine-associated axillary lymphadenopathy. Therefore, they should exercise care, that contemporary anti-COVID-19 vaccination can present an aetiology of axillary lymph nodes with suspicious USG features.

Understanding COVID Vaccination and Its Implication in Cancer Patients’ Imaging of Lymph Nodes by PET-CT

(1) Background: The appearance of enlarged lymph nodes on imaging adds another layer of complexity to the differential diagnosis of disease progression versus immune response to COVID-19 vaccines. Our aim was to find an optimal timing between the vaccination and the PET-CT scan. (2) Methods: 25 cancer patients with ¹⁸F-FDG PET-CT evaluations and a history of COVID-19 vaccination between September 2021 and December 2021 were retrospectively analyzed to characterize the lymph nodes related to the time interval from COVID vaccination. (3) Results: All patients presented one or more adenopathies localized in the ipsilateral axilla (96%), ipsilateral cervical area (20%), ipsilateral retropectoral (20%) and pulmonary hilum (8%). The median value of SUVmax was 3.5 ± 0.5. There was a significant indirect correlation between SUVmax and the time passed between the vaccination and the PET CT (Pearson Correlation r = −0.54, p = 0.005). There was no significant difference (p = 0.19) in the SUVmax value in patients receiving Moderna mRNA-1273 vaccine vs. BNT162b2 mRNA Pfizer vaccine. (4) Conclusions: Lymph node enlargement is commonly seen in patients post-vaccination for COVID-19 and must be differentiated from disease progression. The data from our study strongly suggests that the minimum interval of time between an mRNA vaccine and a PET-CT should be more than six weeks.

Axillary Lymphadenopathy in the COVID-19 Era: What the Radiologist Needs to Know

Axillary lymphadenopathy caused by the high immunogenicity of messenger RNA (mRNA) COVID-19 vaccines presents radiologists with new diagnostic dilemmas in differentiating vaccine-related benign reactive lymphadenopathy from that due to malignant causes. Understanding axillary anatomy and lymphatic drainage is key to radiologic evaluation of the axilla. US plays a critical role in evaluation and classification of axillary lymph nodes on the basis of their cortical and hilar morphology, which allows prediction of metastatic disease. Guidelines for evaluation and management of axillary lymphadenopathy continue to evolve as radiologists gain more experience with axillary lymphadenopathy related to COVID-19 vaccines. General guidelines recommend documenting vaccination dates and laterality and administering all vaccine doses contralateral to the site of primary malignancy whenever applicable. Guidelines also recommend against postponing imaging for urgent clinical indications or for treatment planning in patients with newly diagnosed breast cancer. Although conservative management approaches to axillary lymphadenopathy initially recommended universal short-interval imaging follow-up, updates to those approaches as well as risk-stratified approaches recommend interpreting lymphadenopathy in the context of both vaccination timing and the patient’s overall risk of metastatic disease. Patients with active breast cancer in the pretreatment or peritreatment phase should be evaluated with standard imaging protocols regardless of vaccination status. Tissue sampling and multidisciplinary discussion remain useful in management of complex cases, including increasing lymphadenopathy at follow-up imaging, MRI evaluation of extent of disease, response to neoadjuvant treatment, and potentially confounding cases.

An invited commentary by Weinstein is available online.

^©RSNA, 2022

SARS-CoV-2 vaccination site as possible pitfall on somatostatin receptor imaging

SARS-CoV-2 (COVID-19) vaccination numbers are globally increasing. Therefore, an increased chance exists that patients undergoing Peptide Receptor Radionuclide Therapy (PRRT) or diagnostic radionuclide imaging for Neuroendocrine Tumours (NETs) may have recently received vaccination. We report the imaging findings of two NETs patients, A—following [¹⁷⁷Lu] Lu-DOTATATE PRRT post therapy planar scintigraphy and single photon emission computed tomography with computed tomography (SPECT/CT), and B—following [⁶⁸ Ga]Ga-DOTA-NOC positron emission tomography with computed tomography (PET/CT) respectively. Both studies were done few days after COVID-19 vaccination. Patient A showed a new focus of uptake in the left deltoid muscle; and Patient B showed uptake in the left deltoid and a left axillary lymph node. Nuclear Physicians need to be aware of pitfalls with somatostatin receptor radionuclide imaging post-vaccination to ensure accurate interpretation, as well as dosimetric considerations with vaccine-related post-therapy uptake.

Mammographic findings of diffuse axillary tail trabecular thickening following immunization with mRNA COVID-19 vaccines: Case series study

Axillary lymphadenopathy has been reported after ipsilateral COVID-19 vaccination and can cause confusion for possible malignancy [1]. Intrinsic findings isolated to the breast has not been previously reported. This is the first case series of ipsilateral reversible changes of diffuse axillary tail trabecular thickening on screening mammography in totally asymptomatic patients in connection with COVID vaccination, 3 of which were isolated findings, confirmed by complete resolution of all imaging findings on follow up. In all instances, imaging was performed within 1 week of the first or third dose of an mRNA COVID-19 vaccine. These findings can be confused with breast cancer. Spontaneous resolution distinguishes vaccine-related findings from breast cancer.

Outcomes of COVID-19 Vaccination-Related Incidental Axillary Adenopathy in Women Undergoing Breast MRI

OBJECTIVE

To assess the frequency, management, and early outcomes of COVID-19 vaccine-related adenopathy on breast MRI.

METHODS

This IRB-exempt retrospective study reviewed patients who underwent breast MRI following COVID-19 vaccine approval in the U.S. from December 14, 2020, to April 11, 2021 (N = 1912) and compared patients who underwent breast MRI the year prior to the pandemic, March 13, 2019, to March 12, 2020 (N = 5342). Study indication, patient age, date of study, date and type of vaccination(s), time difference between study and vaccinations, lymph node-specific and overall management recommendations, and outcomes of additional examinations were recorded. Differences in the final assessment categories between the subjects scanned pre-pandemic and post-vaccine were compared using the Fisher exact test.

RESULTS

Vaccine-related adenopathy was mentioned in 67 breast MRI reports; only 1 in the pre-pandemic group. There were no clinically relevant differences in patient demographics between groups. There was a statistically significant increase in BI-RADS 0 assessments between the pre-pandemic and post-vaccine approval groups-0.8% (45/5342) versus 1.8% (34/1912) (P = 0.001) and BI-RADS 3 assessments-6.5% (348/5342) versus 9.2% (176/1912) (P < 0.0001). Of the 29 patients who underwent additional imaging (range, 2-94 days following MRI) and the 2 patients who underwent biopsy, 47% (31/66), none were found to have malignant adenopathy.

CONCLUSION

COVID-19 vaccination is associated with transient axillary adenopathy of variable duration. This leads to additional imaging in women undergoing breast MRI, so far with benign outcomes, and this may affect audits of outcomes of MRI.

Axillary lymph node characteristics in breast cancer patients versus post-COVID-19 vaccination: Overview of current evidence per imaging modality

BACKGROUND

Axillary lymph node characteristics on axillary ultrasound (US), breast MRI and 18F-FDG PET/CT are relevant at breast cancer diagnosis. Axillary lymphadenopathy after COVID-19 vaccination has been frequently reported. This may cause a diagnostic dilemma, particularly in the ipsilateral axilla in women who have a either a recent diagnosis of breast cancer or a history of breast cancer. This review provides an overview of the current evidence regarding axillary lymph node characteristics at breast cancer diagnosis versus "post-COVID-19 vaccination".

METHODS

A non-systematic narrative review was performed. Studies describing axillary lymph node characteristics per imaging modality (axillary US, breast MRI and 18F-FDG PET/CT) in breast cancer patients versus post-COVID-19 vaccination were selected and used for the current study.

RESULTS

The morphologic characteristics and distribution of abnormal nodes on US may differ from the appearance of metastatic adenopathy since diffuse cortical thickening of the lymph nodes is the most observed characteristic after vaccination, whereas metastases show as most suspicious characteristics focal cortical thickening and effacement of the fatty hilum. Current evidence on MRI and 18F-FDG on morphologic characteristics of axillary lymphadenopathy is missing, although it was suggested that vaccine related lymphadenopathy is more likely to be present in level 2 and 3 nodes than metastatic nodes. Reported frequencies of lymphadenopathy post-COVID-19 vaccination range from 49% to 85% (US), 29% (breast MRI) and 14.5% to 53.9% (18F-FDG PET/CT). Several factors may impact the presence or extent of lymphadenopathy post-COVID-19 vaccination: injection site, type of vaccine (i.e., mRNA versus vector), time interval (days) between vaccination and imaging, previous history of COVID-19 pneumonia, and first versus second vaccine dose.

CONCLUSION

Although lymph node characteristics differ at breast cancer diagnosis versus post-COVID-19 vaccination, clinical information regarding injection site, vaccine type and vaccination date needs to be documented to improve the interpretation and guide treatment towards the next steps of action.

Time for Resolution of COVID-19 Vaccine-Related Lymphadenopathy and Associated Factors

Background. The variable clinical course of subclinical lymphadenopathy detected on breast imaging after COVID-19 vaccination creates management challenges and has led to evolving practice recommendations. Objective. To assess the duration of axillary lymphadenopathy ipsilateral to COVID-19 vaccination detected by breast imaging and to assess factors associated with the time until resolution. Methods. This retrospective single-center study included 111 patients (mean, 52±12 years) with unilateral axillary lymphadenopathy ipsilateral to Pfizer or Moderna COVID-19 vaccine administration performed within the prior 8 weeks that was detected on breast ultrasound performed between January 1st, 2021, and October 1st, 2021 and that underwent follow-up ultrasound examinations at 4-12 week intervals until resolution of the lymphadenopathy. Patient information was extracted from medical records. Cortical thickness of the largest axillary lymph node on ultrasound was retrospectively measured and was considered enlarged when greater than 3 mm. Multivariable linear regression analysis was used to identify independent predictors of the time until resolution. Results. The mean cortical thickness on the initial ultrasound was 4.7±1.2 mm. The lymphadenopathy resolved a mean of 97±44 days after the initial ultrasound and 127±43 days after the first vaccine dose, as well as after a mean of 2.4±0.6 follow-up ultrasound examinations. Significant independent predictor of shorter time to resolution was Pfizer (rather than Moderna) vaccination [coefficient=-18.0 (95% CI: -34.3, -1.7); p=.03], and significant independent predictors of longer time to resolution were receipt of the second dose after the initial ultrasound [coefficient=19.2 (95% CI: 3.1, 35.2); p=.02] and greater cortical thickness on the initial ultrasound [coefficient=8.0 (95% CI: 1.5, 14.5); p=.02]. Patient age, prior history of breast cancer, and axillary symptoms were not significantly associated with time to resolution (all p>.05). Conclusion. Axillary lymphadenopathy detected by breast ultrasound after COVID-19 mRNA vaccination lasts longer than reported in initial vaccine clinical trials. Clinical Impact. The prolonged time for resolution supports not delaying screening mammography due to recent COVID-19 vaccination as well as the recent professional society recommendation of a follow-up interval of at least 12 weeks for suspected vaccine-related lymphadenopathy.

COVID-19 vaccine-induced lymphadenopathies: incidence, course and imaging features from an ultrasound prospective study

Aims

lymphadenopathy can occur after COVID-19 vaccination and when encountered at ultrasound examinations performed for other reasons might pose a diagnostic challenge. Purpose of the study was to evaluate the incidence, course and ultrasound imaging features of vaccine-induced lymphadenopathy.

Methods

89 healthy volunteers (median age 30, 76 females) were prospectively enrolled. Vaccine-related clinical side effects (e.g., fever, fatigue, palpable or painful lymphadenopathy) were recorded. Participants underwent bilateral axillary, supraclavicular and cervical lymph node stations ultrasound 1–4 weeks after the second dose and then again after 4–12 weeks in those who showed lymphadenopathy at the first ultrasound. B-mode, color-Doppler assessment, and shear-wave elastography (SWE) evaluation were performed. The correlation between lymphadenopathy and vaccine-related side effects was assessed using the Fisher’s exact test.

Results

Post-vaccine lymphadenopathy were found in 69/89 (78%) participants (37 single and 32 multiple lymphadenopathy). Among them, 60 presented vaccine-related side effects, but no statistically significant difference was observed between post-vaccine side effect and lymphadenopathy. Ultrasound features of vaccine-related lymphadenopathy consisted of absence of fatty hilum, round shape and diffuse or asymmetric cortical thickness (median cortical thickness of 5 mm). Vascular signal was mainly found to be increased, localized in both central and peripheral regions. SWE showed a soft cortical consistence in all cases (median value 11 Kpa). At follow-up, lymph-node morphology was completely restored in most cases (54/69, 78%) and in no case lymphadenopathy had worsened.

Conclusion

A high incidence of vaccine-induced lymphadenopathy was found in a population of healthy subjects, with nearly complete regression within 4–12 weeks.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40477-022-00674-3.

Outcomes of single dose COVID-19 vaccines: Eight month follow-up of a large cohort in Saudi Arabia

BACKGROUND

Two vaccines for COVID-19 have been approved and administered in the Kingdom of Saudi Arabia (KSA); Pfizer-BioNtech BNT162b2 and AstraZeneca-Oxford AZD1222 vaccines. The purpose of this study was to describe the real-world data on the outcome of single dose of these COVID-19 vaccines in a large cohort in KSA and to analyse demographics and co-morbidities as risk factors for infection post one-dose vaccination.

METHODS

In this prospective cohort study, a total of 18,543 subjects received one dose of either of the vaccines at a vaccination centre in KSA, and were followed up for three to eight months. Data were collected from three sources; clinical data from medical records, adverse events (AEs) from a self-reporting system, and COVID-19 infection data from the national databases. The study was conducted during the pandemic restrictions on travel, mobility, and social interactions.

RESULTS

The median age of participants was 33 years with an average body mass index of 27.3. The majority were males (60.1%). Results showed that 92.17% of the subjects had no COVID-19 infection post-vaccination as infection post-vaccination was documented for 1452 (7.83%). Diabetes mellitus 03), organ transplantation (p = 0.02), and obesity (p < 0.01) were associated with infection post-vaccination. Unlike vaccine type, being Saudi, male, or obese was associated with the occurrence breakthrough infections more than other parameters. AEs included injection site pain, fatigue, fever, myalgia, headache and was reported by 5.8% of the subjects.

CONCLUSION

Single dose COVID-19 vaccines showed a protection rate of 92.17% up to eight months follow-up in this cohort. This rate in AZD1222 was higher than what have been previously reported in effectiveness studies and clinical trials. Obese, male, and Saudi were at higher risk of contracting the infection post-vaccination, Saudi and male might have more social interaction with the public when mobility and social interactions were limited during the pandemic. Side effects and AEs were within what has been reported in clinical trials.

Unilateral Axillary Lymphadenopathy After COVID-19 Vaccine Causing Medial Cord Plexopathy: A Case Report

CASE

The global reach of coronavirus disease 2019 has led to the rollout of new generation messenger ribonucleic acid (mRNA) vaccines. As populations are vaccinated, some side effects will become more apparent. We present a case of unilateral lymphadenopathy resulting in a transient plexopathy presenting as neuralgic pain, paresthesia, and numbness in the hand.

CONCLUSION

Multiple image modalities and electrodiagnostic studies were used to infer the diagnosis. This condition was expectantly managed, and the patient's symptoms resolved within weeks.

Frequency of Ipsilateral Axillary Lymphadenopathy After the Inactivated COVID-19 Vaccine

OBJECTIVE

During COVID-19 vaccine development studies, vaccines' efficacy and safety profiles should be carefully investigated. Only a few studies have shown that the COVID-19 vaccine can cause axillary lymphadenopathy on the injection arm. This study aimed to investigate the incidence of axillary lymphadenopathy and imaging findings using B-mode and Doppler ultrasonography (US) examinations in volunteers who had recently been vaccinated against COVID-19.

METHODS

The ipsilateral and contralateral axillae of 101 volunteers who received the COVID-19 vaccine were evaluated using B-mode and Doppler US examinations. The volunteers were asked when and to which arm the vaccine had been applied, and the type and dose of the vaccine were recorded. It was also questioned whether the individual experienced any side effects after vaccination, such as pain, tenderness, fever, and redness at the injection site. In addition, the demographic data of the participants, such as age and gender were recorded.

RESULTS

The B-mode US examinations revealed that the long- and short-axis diameters, size, cortical thickness and asymmetric cortical thickening of the left axillary lymph nodes were significantly higher compared to the right side in individuals having received the CoronaVac vaccine (p<0.05). When the individuals were evaluated separately according to gender, the frequency of cortical thickness and asymmetric cortical thickening in the left axillary lymph nodes was higher than on the right side in both males and females (p=0.011).

CONCLUSION

It should be kept in mind that ipsilateral reactive lymphadenopathy may develop after the COVID-19 vaccine. This knowledge can prevent unnecessary axillary lymph node biopsies.

Breastfeeding Mother and Child Clinical Outcomes After COVID-19 Vaccination

BACKGROUND

Pre-approval clinical trials of the Pfizer/BioNTech messenger RNA COVID-19 vaccine, BNT162b2 did not include participants who were breastfeeding. Therefore, there is limited evidence about outcomes of breastfeeding mother-child dyads and effects on breastfeeding after vaccination.

RESEARCH AIMS

To determine: (1) solicited adverse effects (e.g., axillary lymphadenopathy, mastitis, and breast engorgement), which are unique to lactating individuals; and (2) systemic and local adverse effects of COVID-19 mRNA vaccine on mothers and potential effects on their breastfed infants.

METHOD

This was a prospective cohort study of lactating healthcare workers (N = 88) in Singapore who received two doses of BNT162b2 vaccination (Pfizer/BioNTech). The outcomes of mother-child dyads within 28 days after the second vaccine dose were determined through a participant-completed questionnaire.

RESULTS

Minimal effects related to breastfeeding were reported by this cohort; three of 88 (3.4%) participants had mastitis, one (1.1%) participant experienced breast engorgement, five of 88 (5.7%) participants reported cervical or axillary lymphadenopathy. There was no change in human milk supply after vaccination. The most common side effect was pain/redness/swelling at the injection site, which was experienced by 57 (64.8%) participants. There were no serious adverse events of anaphylaxis or hospital admissions. There were no short-term adverse effects reported in the infants of 67 lactating participants who breastfed within 72 hr after BNT162b2 vaccination.

CONCLUSIONS

BNT162b2 vaccination was well tolerated in lactating participants and was not associated with short-term adverse effects in their breastfed infants.

STUDY PROTOCOL REGISTRATION

The study protocol was registered at clinicaltrials.gov (NCT04802278).

Lung Cancer Screening Considerations During Respiratory Infection Outbreaks, Epidemics or Pandemics: An International Association for the Study of Lung Cancer Early Detection and Screening Committee Report

After the results of two large, randomized trials, the global implementation of lung cancer screening is of utmost importance. However, coronavirus disease 2019 infections occurring at heightened levels during the current global pandemic and also other respiratory infections can influence scan interpretation and screening safety and uptake. Several respiratory infections can lead to lesions that mimic malignant nodules and other imaging changes suggesting malignancy, leading to an increased level of follow-up procedures or even invasive diagnostic procedures. In periods of increased rates of respiratory infections from severe acute respiratory syndrome coronavirus 2 and others, there is also a risk of transmission of these infections to the health care providers, the screenees, and patients. This became evident with the severe acute respiratory syndrome coronavirus 2 pandemic that led to a temporary global stoppage of lung cancer and other cancer screening programs. Data on the optimal management of these situations are not available. The pandemic is still ongoing and further periods of increased respiratory infections will come, in which practical guidance would be helpful. The aims of this report were: (1) to summarize the data available for possible false-positive results owing to respiratory infections; (2) to evaluate the safety concerns for screening during times of increased respiratory infections, especially during a regional outbreak or an epidemic or pandemic event; (3) to provide guidance on these situations; and (4) to stimulate research and discussions about these scenarios.

Which Type of the Promising COVID-19 Vaccines Produces Minimal Adverse Effects? A Retrospective Cross-Sectional Study

Since the declaration of Coronavirus-2019 (COVID-19) as a pandemic by the World Health Organization (WHO), it was clear that vaccination is the best way to overcome it. Sinopharm, AstraZeneca and Pfizer were the first vaccines introduced to defeat it. To recognize the short-term adverse effects among Iraqi health care workers (HCWs) after vaccination, the three COVID-19 vaccines that are currently available in Iraq were compared. An online survey was distributed to Iraqi HCWs who had received at least one of the COVID-19 vaccines as part of a retrospective cross-sectional study. Data were statistically analyzed using SPSS. The total number of participants was 843. The majority of the participants (85.9%) were under 39 years old, with 78.8% of them being females. Around 60% of individuals had received the Pfizer vaccine. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had infected 46.7% of the total participants. A total of 628 out of 843 participants experienced adverse effects after receiving the vaccine, accounting for 74.49% of the overall respondents. After receiving the COVID-19 vaccine, the vast majority of respondents who received the three vaccines experienced pain at the injection site (n = 800), while other side effects like headache, myalgia, tiredness and fever mainly appeared with Pfizer and AstraZeneca vaccines. Most of the reported adverse effects were tolerable and self-limited and they were linked to the AstraZeneca and Pfizer vaccines.

PET/CT variants and pitfalls in malignant melanoma

¹⁸F-FDG PET/CT plays an increasingly pivotal role in the staging and post-treatment monitoring of high-risk melanoma patients, augmented by the introduction of therapies, including tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICIs), that have novel modes of action that challenge conventional response assessment. Simultaneously, technological advances have been regularly released, including advanced reconstruction algorithms, digital PET and motion correction, which have allowed the PET community to detect ever-smaller cancer lesions, improving diagnostic performance in the context of indications previously viewed as limitations, such as detection of in-transit disease and confirmation of the nature of small pulmonary metastases apparent on CT.This review will provide advice regarding melanoma-related PET protocols and will focus on variants encountered during the imaging of melanoma patients. Emphasis will be made on pitfalls related to non-malignant diseases and treatment-related findings that may confound accurate interpretation unless recognized. The latter include signs of immune activation and immune-related adverse events (irAEs). Technology-related pitfalls are also discussed, since while new PET technologies improve detection of small lesions, these may also induce false-positive cases and require a learning curve to be observed. In these times of the COVID 19 pandemic, cases illustrating lessons learned from COVID 19 or vaccination-related pitfalls will also be described.

COVID-19 mRNA Vaccination: Age and Immune Status and Its Association with Axillary Lymph Node PET/CT Uptake

With hundreds of millions of coronavirus disease 2019 (COVID-19) messenger RNA (mRNA)-based vaccine doses planned to be delivered worldwide in the upcoming months, it is important to recognize PET/CT findings in recently vaccinated immunocompetent or immunocompromised patients. We aimed to assess PET/CT uptake in the deltoid muscle and axillary lymph nodes of patients who received a COVID-19 mRNA-based vaccine and to evaluate its association with patient age and immune status. Methods: All consecutive adults who underwent PET/CT scans with any radiotracer at our center during the first month of a national COVID-19 vaccination rollout (between December 23, 2020, and January 27, 2021) and had received the vaccination were included. Data on clinical status, laterality, and time from vaccination were prospectively collected, retrospectively analyzed, and correlated with deltoid muscle and axillary lymph node uptake. Results: Of 426 eligible subjects (median age, 67 ± 12 y; 49% female), 377 (88%) underwent PET/CT with 18F-FDG, and positive axillary lymph node uptake was seen in 45% of them. Multivariate logistic regression analysis revealed a strong inverse association between positive 18F-FDG uptake in ipsilateral lymph nodes and patient age (odds ratio [OR], 0.57; 95% CI, 0.45-0.72; P < 0.001), immunosuppressive treatment (OR, 0.37; 95% CI, 0.20-0.64; P = 0.003), and presence of hematologic disease (OR, 0.44; 95% CI, 0.24-0.8; P = 0.021). No such association was found for deltoid muscle uptake. The number of days from the last vaccination and the number of vaccine doses were also significantly associated with increased odds of positive lymph node uptake. Conclusion: After mRNA-based COVID-19 vaccination, a high proportion of patients showed ipsilateral lymph node axillary uptake, which was more common in immunocompetent patients. This information will help with the recognition of PET/CT pitfalls and may hint about the patient's immune response to the vaccine.

Intensity of hypermetabolic axillary lymph nodes in oncologic patients in relation to timeline following COVID-19 vaccination

Purpose

First discovered in Wuhan, China in December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is a highly contagious and deadly novel virus that quickly wreaked havoc throughout the world. As mass vaccination are now underway worldwide, clinicians have started to encounter a new clinical entity, COVID-19 vaccine-associated axillary lymphadenopathy. This presents a unique challenge to medical imagers, particularly in oncologic patients.

Methods

In this retrospective study, we assessed metabolic activity, size, and timeline of COVID-19 vaccine-associated axillary hypermetabolic lymph nodes in 202 oncologic patients post vaccination with 18-fluorodeoxyglucose positron emission tomography (18-FDG PET).

Results

When present, COVID-19 vaccine-associated hypermetabolic lymph nodes demonstrate a mean maximum standard uptake value (SUV_max) of 2.5 ± 0.3, and more common in younger patients. The metabolic activity is the most intense in the first two weeks post vaccination and diminishes over time. By approximately 5-6 weeks, only about half of the patients demonstrated appreciable, low grade uptake compared to background.

Conclusion

Based on our preliminary results, we would recommend correlation with a history and time of vaccination and routine use of a pre-study patient questionnaire to guide interpretation to prevent over-diagnosis of axillary nodal metastases and/or unnecessary work-up in oncologic patients.

Ipsilateral Malignant Axillary Lymphadenopathy and Contralateral Reactive Lymph Nodes in a COVID-19 Vaccine Recipient With Breast Cancer

Vaccine-related axillary nodal enlargement is a common benign condition that many mRNA vaccine receivers experience. However, a false attribution of axillary swelling to vaccination may result in delay in cancer care and potential disease progression, particularly in breast cancer patients presenting with ipsilateral axillary lymphadenopathy. We report the case of a 41-year-old pre-menopausal female who presented with suspicious axillary nodal enlargement and a right breast lump (triple-negative invasive ductal carcinoma) after recent administration of the second dose of Moderna mRNA coronavirus disease 2019 (COVID-19) vaccine. On imaging, bilateral axillary lymph nodes were detected. The ipsilateral right-sided node was proven to be metastatic, whereas contralateral nodes were related to a recent mRNA COVID-19 vaccination. Right-sided lymph node had intense uptake (maximum standardized uptake value [SUVmax] = 5), while the contralateral reactive nodes were mildly avid (SUVmax = 2.6). On magnetic resonance imaging, the right-sided node revealed asymmetric cortical thickening and marked cortical enhancement as opposed to normal-appearing left-sided nodes.

FDG-PET/CT of COVID-19 and Other Lung Infections

While not conventionally used as the first-line modality, [¹⁸F]-2-fluoro-2-deoxy-D-glucose (FDG) - positron emission tomography/computed tomography (PET/CT) can identify infection and inflammation both earlier and with higher sensitivity than anatomic imaging modalities [including chest X-ray (CXR), computed tomography (CT), and magnetic resonance imaging (MRI)]. The extent of inflammation and, conversely, recovery within the lungs, can be roughly quantified on FDG-PET/CT using maximum standardized uptake value (SUVmax) values. The Coronavirus disease 2019 (COVID-19) pandemic has highlighted the value of FDG-PET/CT in diagnosis, elucidation of acute pulmonary and extrapulmonary manifestations, and long-term follow up. Similarly, many other pulmonary infections such as previously documented coronaviruses, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, mucormycosis, and typical/atypical mycobacterial infections have all been identified and characterized using FDG-PET/CT imaging. The goal of this review is to summarize the actual and potential benefits of FDG-PET/CT in the imaging of COVID-19 and other lung infections. Further research is necessary to determine the best indications and clinical applications of FDG-PET/CT, improve its specificity, and ultimately ascertain how this modality can best be utilized in the diagnostic work up of infectious pathologies.

COVID Lessons Continue: Postvaccination Somatostatin Receptor-Positive Axillary Nodes on DOTATATE Imaging

ABSTRACT

COVID vaccination has begun in most of the countries. Older population and high-risk groups are prioritized for vaccination. Postvaccination imaging in cancer patients may show effects of the immune response to the vaccine. As such, it is important to know the timing and laterality of the vaccination as the reactive lymph nodes in the ipsilateral axilla can be seen on the imaging. We present a case of DOTATATE-avid nonpathologically enlarged lymph nodes in ipsilateral axilla and linear tracer uptake in the deltoid muscle on a patient imaged for a recent diagnosis of rectal neuroendocrine neoplasm.

Management Strategies for Patients Presenting With Symptomatic Lymphadenopathy and Breast Edema After Recent COVID-19 Vaccination

Ipsilateral axillary lymphadenopathy is a well-documented finding associated with COVID-19 vaccination. Varying guidelines have been published for the management of asymptomatic patients with history of recent vaccination who present with incidental lymphadenopathy on screening mammography. Some experts recommend follow-up imaging, while others suggest that clinical management, rather than repeat imaging or biopsy, is appropriate. Patients with symptomatic lymphadenopathy and/or additional abnormal imaging findings should be managed differently depending on risk factors and clinical scenarios. While ipsilateral lymphadenopathy is well documented, ipsilateral breast edema after COVID-19 vaccination has been rarely reported. The combination of ipsilateral lymphadenopathy and diffuse breast edema after COVID-19 vaccination presents a clinical management challenge, as edema may obscure underlying abnormalities on imaging. We propose that, in patients with symptomatic lymphadenopathy and associated breast parenchymal abnormality, prompt action is appropriate, including diagnostic evaluation and consideration for tissue sampling. This approach may prevent delays in diagnosis and treatment for patients with malignancy masked by symptoms from the vaccination.

COVID-19 vaccine-related axillary edema in breast imaging setting

Worldwide, many vaccines have been developed in response to the COVID-19 pandemic. Unilateral reactive axillary adenopathy related to the COVID-19 vaccine is a well-known occurrence. In addition, axillary edema has also been observed following COVID-19 vaccinations in patients undergoing breast MRI, and radiologists need to be aware of this possibility to avoid performing unnecessary work-up that can be costly to the health care system and be stressful for patients.

The incidence and duration of COVID-19 vaccine-related reactive lymphadenopathy on 18F-FDG PET-CT

OBJECTIVES

Reactive axillary lymph nodes (ALN) may occur post-COVID-19 vaccination. This may be confused with malignant nodal metastases on oncological imaging. We aimed to determine the reactive ALN incidence and duration on ¹⁸F-fluorodeoxyglucose positron emission tomography - computed tomography (¹⁸F-FDG PET-CT), and its relationship with gender, age and vaccine type.

METHODS

A retrospective study was performed. Two-hundred and four eligible patients had ¹⁸F-FDG PET-CT between 01 January 2021 and 31 March 2021, post-vaccination with Pfizer-BioNTech or Oxford-AstraZeneca vaccine. Image analysis was performed on dedicated workstations. SPSS was used for statistical analysis.

RESULTS

Thirty-six per cent of patients had reactive ALN until 10 weeks post-vaccination; reducing in frequency and intensity with time. Women were more likely to have reactive ALN compared with men. The frequency and intensity were higher in patients aged <65 years compared with those aged ≥65 years. However, no difference was found between both vaccine types in our study cohort.

CONCLUSIONS

Physicians' awareness of COVID-19 vaccine-related reactive ALN on ¹⁸F-FDG PET-CT is important to avoid inappropriate upstaging of cancers.

Melanoma Management during the COVID-19 Pandemic Emergency: A Literature Review and Single-Center Experience

Simple Summary

COVID-19 is a highly contagious infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In March 2020, the World Health Organization (WHO) declared that COVID-19 had become a pandemic; since then, several elective clinical and surgical activities have been postponed to reduce the risk of nosocomial infection. This has influenced the diagnosis and management of many diseases, including melanoma. The aim of our literature review was to evaluate whether the management of melanoma has been changed by the outbreak of COVID-19, and if so, what the consequences of these changes are. The main topics in this literature review are the screening of suspicious lesions, diagnosis of primary melanoma, and the management of early-stage and advanced melanomas in the COVID-19 era. We also reported the experience of our dermatological clinic in Turin, one of the most affected areas in Italy.

Abstract

Background: The current COVID-19 pandemic has influenced the modus operandi of all fields of medicine, significantly impacting patients with oncological diseases and multiple comorbidities. Thus, in recent months, the establishment of melanoma management during the emergency has become a major area of interest. In addition to original articles, case reports and specific guidelines for the period have been developed. Purpose: This article aims to evaluate whether melanoma management has been changed by the outbreak of COVID-19, and if so, what the consequences are. We summarized the main issues concerning the screening of suspicious lesions, the diagnosis of primary melanoma, and the management of early-stage and advanced melanomas during the pandemic. Additionally, we report on the experience of our dermatological clinic in northern Italy. Methods: We performed a literature review evaluating articles on melanomas and COVID-19 published in the last two years on PubMed, as well as considering publications by major healthcare organizations. Concerning oncological practice in our center, we collected data on surgical and therapeutic procedures in patients with a melanoma performed during the first months of the pandemic. Conclusions: During the emergency period, the evaluation of suspicious skin lesions was ensured as much as possible. However, the reduced level of access to medical care led to a documented delay in the diagnosis of new melanomas. When detected, the management of early-stage and advanced melanomas was fully guaranteed, whereas the follow-up visits of disease-free patients have been postponed or replaced with a teleconsultation when possible.

False-Positive Axillary Lymph Nodes on FDG PET/CT Resulting From COVID-19 Immunization

ABSTRACT

World-wide mass COVID-19 vaccination has been deployed starting with those most vulnerable, including the elderly and cancer patients. A 70-year-old man with right lung cancer underwent staging FDG PET/CT, which demonstrated an avid right lung mass with avid hilar and mediastinal nodes. Avid left axillary nodes of benign configuration were also noted. The patient had the Oxford-AstraZeneca COVID-19 vaccination in the left arm a week earlier. On reflection, the axillary nodes were concluded to be reactive related to this. This is a potential COVID-19 vaccination associated pitfall on PET/CT that should be considered when interpreting FDG PET/CT images.

COVID-19 vaccine-related axillary lymphadenopathy in breast cancer patients: Case series with a review of literature

Purpose

Lymphadenopathy (LAP) after COVID-19 vaccination in patients with a diagnosis of cancer has been challenging. We analyzed imaging and clinical features from early cases of axillary LAP in six COVID-19 vaccine recipients with a history of breast cancer.

Method

Among the patients with a history of breast cancer and recent COVID-19 vaccine administration, six patients who showed isolated axillary LAP were gathered. Radiologic features were reviewed from breast ultrasound, chest computed tomography, and breast magnetic resonance imaging. Clinical and pathological information were obtained for analysis.

Results

The interval between ultrasound detection of LAP and last COVID-19 vaccine administration ranged from 14 to 28 days (mean 21.67 days). Round shape of the lymph node and irregular cortex were noted in 2 and 0 cases, respectively. Mean maximum cortical thickness, length to width ratio and interval aggravation in maximum cortical thickening were 4.2 mm, 1.34, and 2.81-fold with cut-off value of 3 mm, 1.5, 2.0-fold, respectively.

Conclusion

We observed axillary LAP ipsilateral to a recent vaccine administration persisting longer than what the Centers for Disease Control and Prevention announced. In our patients, COVID-19 vaccine-related LAP tended to show increased cortical thickness without cortical irregularity. Oncologist as well as radiologist should be familiar with the fact that COVID-19 vaccines, regardless of vaccine type or dosage, can frequently cause ipsilateral axillary LAP, showing some suspicious features more often than others, and can persist longer than anticipated so that both over- and underdiagnosis can be avoided. We report our observations in six patients and provide an exhaustive review of the published literature

COVID-19 Vaccine-Related Axillary and Cervical Lymphadenopathy in Patients with Current or Prior Breast Cancer and Other Malignancies: Cross-Sectional Imaging Findings on MRI, CT, and PET-CT

Breast radiologists are increasingly seeing patients with axillary adenopathy related to COVID-19 vaccination. Vaccination can cause levels I–III axillary as well as cervical lymphadenopathy. Appropriate management of vaccine-related adenopathy may vary depending on clinical context. In patients with current or past history of malignancy, vaccine-related adenopathy can be indistinguishable from nodal metastasis. This article presents imaging findings of oncology patients with adenopathy seen in the axilla or neck on cross-sectional imaging (breast MRI, CT, or PET-CT) after COVID-19 vaccination. Management approach and rationale is discussed, along with consideration on strategies to minimize false positives in vaccinated cancer patients. Time interval between vaccination and adenopathy seen on breast MRI, CT, or PET-CT is also reported.

DOTATATE -Avid Bilateral Axilla and Subpectoral Lymphadenopathy Induced From COVID-19 mRNA Vaccination Visualized on PET/CT

ABSTRACT

A 64-year-old woman with malignant carcinoid tumor of the ileum received right ileocolectomy 9 years ago. Series follow-up imaging studies including most recent 68Ga-DOTATATE PET/CT scan in June 2020 have been negative for disease. Current 68Ga-DOTATATE PET/CT scan showed new cluster of bilateral axillary and subpectoral lymphadenopathy with normal CT morphology, but with avid DOTATATE uptake. There was no other abnormal DOTATATE-avid lesion or suspicious CT image findings. The medical history revealed that the patient received 2 doses of COVID-19 (coronavirus disease 2019) mRNA vaccine at bilateral upper arm deltoid muscles at 21 and 42 days prior to the PET/CT examination, respectively.

Temporal metabolic response to mRNA COVID-19 vaccinations in oncology patients

BACKGROUND

mRNA COVID-19 vaccines are known to provide an immune response seen on FDG PET studies. However, the time course of this metabolic response is unknown. We here present a temporal metabolic response to mRNA COVID-19 vaccination in oncology patients undergoing standard of care FDG PET.

METHODS

262 oncology patients undergoing standard of care FDG PET were included in the analysis. 231 patients had at least one dose of mRNA COVID-19 vaccine while 31 patients had not been vaccinated. The SUVmax of the lymph nodes ipsilateral to the vaccination was compared to the contralateral to obtain an absolute change in SUVmax (ΔSUVmax).

RESULTS

ΔSUVmax was more significant at shorter times between FDG PET imaging and COVID-19 mRNA vaccination, with a median ΔSUVmax of 2.6 (0-7 days), 0.8 (8-14 days), and 0.3 (> 14 days), respectively.

CONCLUSION

Consideration should be given to performing FDG PET at least 2 weeks after the COVID-19 vaccine.

Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Hodgkin's Lymphoma: Diagnostic Challenge during COVID Vaccination

Benign metabolic uptake on fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) is not uncommonly seen after immunization. We report a case of 30-year-old man with Hodgkin's lymphoma who underwent two cycles of chemotherapy. Interim ¹⁸F-FDG PET/computed tomography demonstrated complete metabolic response of prior hypermetabolic bilateral supraclavicular and mediastinal lymph nodes. Although multiple new normal-sized hypermetabolic left axillary and subpectoral lymph nodes are noted, relevant history revealed COVID vaccine 7 days prior scan with mild FDG uptake at the left deltoid muscle. These new findings at the left axilla are likely related to recent vaccination. ¹⁸F-FDG PET uptake in the lymph nodes is not so uncommon after immunization; relevant history is very important especially in the phase of massive immunization to avoid false interpretation.