Clinical importance of thoracal lymphadenopathy in COVID-19.

BACKGROUND: Thoracal lymphadenopathy may predict prognosis in patients with coronavirus disease 2019 (COVID-19), albeit the reported data is inconclusive. The aim of the present analysis was to analyze the affected lymph node stations and the cumulative lymph node size derived from computed tomography (CT) for prediction of 30-day mortality in patients with COVID-19. METHODS: The clinical database was retrospectively screened for patients with COVID-19 between 2020 and 2022. Overall, 177 patients (63 female, 35.6%) were included into the analysis. Thoracal lymphadenopathy was defined by short axis diameter above 10 mm. Cumulative lymph node size of the largest lymph nodes was calculated and the amount of affected lymph node stations was quantified. RESULTS: Overall, 53 patients (29.9%) died within the 30-day observation period. 108 patients (61.0%) were admitted to the ICU and 91 patients needed to be intubated (51.4%). Overall, there were 130 patients with lymphadenopathy (73.4%). The mean number of affected lymph node levels were higher in non-survivors compared to survivors (mean, 4.0 vs 2.2, p < 0.001). The cumulative size was also higher in non-survivors compared to survivors (mean 55.9 mm versus 44.1 mm, p = 0.006). Presence of lymphadenopathy was associated with 30-day mortality in a multivariable analysis, OR = 2.99 (95% CI 1.20 - 7.43), p = 0.02. CONCLUSIONS: Thoracal lymphadenopathy comprising cumulative size and affected levels derived from CT images is associated with 30-day mortality in patients with COVID-19. COVID-19 patients presenting with thoracic lymphadenopathy should be considered as a risk group.

COVID-19 vaccine related hypermetabolic lymph nodes on PET/CT: Implications of inflammatory findings in cancer imaging.

We observed several patients presenting 2-[18F]FDG uptake in the reactive axillary lymph node at PET/CT imaging, ipsilateral to the site of the COVID-19 vaccine injection. Analog finding was documented at [18F]Choline PET/CT. The aim of our study was to describe this source of false positive cases. All patients examined by PET/CT were included in the study. Data concerning patient anamnesis, laterality, and time interval from recent COVID-19 vaccination were recorded. SUVmax was measured in all lymph nodes expressing tracer uptake after vaccination. Among 712 PET/CT scans with 2-[18F]FDG, 104 were submitted to vaccination; 89/104 patients (85%) presented axillary and/or deltoid tracer uptake, related to recent COVID-19 vaccine administration (median from injection: 11 days). The mean SUVmax of these findings was 2.1 (range 1.6-3.3). Among 89 patients with false positive axillary uptake, 36 subjects had received chemotherapy due to lymph node metastases from somatic cancer or lymphomas, prior to the scan: 6/36 patients with lymph node metastases showed no response to therapy or progression disease. The mean SUVmax value of lymph nodal localizations of somatic cancers/lymphomas after chemotherapy was 7.8. Only 1/31 prostate cancer patients examined by [18F]Choline PET/CT showed post-vaccine axillary lymph node uptake. These findings were not recorded at PET/CT scans with [18F]-6-FDOPA, [68Ga]Ga-DOTATOC, and [18F]-fluoride. Following COVID-19 mass vaccination, a significant percentage of patients examined by 2-[18F]FDG PET/CT presents axillary, reactive lymph node uptake. Anamnesis, low-dose CT, and ultrasonography facilitated correct diagnosis. Semi-quantitative assessment supported the visual analysis of PET/CT data; SUVmax values of metastatic lymph nodes were considerably higher than post-vaccine lymph nodes. [18F]Choline uptake in reactive lymph node after vaccination was confirmed. After the COVID-19 pandemic, nuclear physicians need to take these potential false positive cases into account in daily clinical practice.

Type I IFN stimulates lymph node stromal cells from adult and old mice during a West Nile virus infection.

Advanced age is a significant risk factor during viral infection due to an age-associated decline in the immune response. Older individuals are especially susceptible to severe neuroinvasive disease after West Nile virus (WNV) infection. Previous studies have characterized age-associated defects in hematopoietic immune cells during WNV infection that culminate in diminished antiviral immunity. Situated amongst immune cells in the draining lymph node (DLN) are structural networks of nonhematopoietic lymph node stromal cells (LNSCs). LNSCs are comprised of numerous, diverse subsets, with critical roles in the coordination of robust immune responses. The contributions of LNSCs to WNV immunity and immune senescence are unclear. Here, we examine LNSC responses to WNV within adult and old DLNs. Acute WNV infection triggered cellular infiltration and LNSC expansion in adults. Comparatively, aged DLNs exhibited diminished leukocyte accumulation, delayed LNSC expansion, and altered fibroblast and endothelial cell subset composition, signified by fewer LECs. We established an ex vivo culture system to probe LNSC function. Adult and old LNSCs both recognized an ongoing viral infection primarily through type I IFN signaling. Gene expression signatures were similar between adult and old LNSCs. Aged LNSCs were found to constitutively upregulate immediate early response genes. Collectively, these data suggest LNSCs uniquely respond to WNV infection. We are the first to report age-associated differences in LNSCs on the population and gene expression level during WNV infection. These changes may compromise antiviral immunity, leading to increased WNV disease in older individuals.

Fine needle aspiration in COVID-19 vaccine-associated lymphadenopathy.

AIMS: With ongoing intensive vaccination programme against COVID-19, numerous cases of adverse reactions occur, some of which represent rare events. Enlargement of the injection site’s draining lymph nodes is increasingly reported, but is not yet widely recognised as being possibly associated with recent vaccination. As patients at risk of a severe course of COVID-19, indicated by their medical history such as a previous diagnosis of malignancy, receive priority vaccination, newly palpable lymph nodes raise concerns of disease progression. In this case series, we report on five patients who presented with enlarged lymph nodes after COVID-19 vaccination. METHODS: Sonography guided fine needle aspiration (FNA) was performed in five patients presenting with PET-positive and/or enlarged lymph nodes after COVID-19 vaccination with either the Pfizer-BioNTech or Moderna vaccine. RESULTS: COVID-19 vaccination had been carried out in all cases, with an interval of between 3 and 33 days prior to FNA. Three of five patients had a history of neoplasms. The vaccine was administered into the deltoid muscle, with subsequent enlargement of either the cervical, supra-, infra- or retroclavicular, or axillary lymph nodes, in four out of five cases ipsilaterally. In all cases, cytology and additional analyses showed a reactive lymphadenopathy without any sign of malignancy. CONCLUSIONS: Evidence of newly enlarged lymph nodes after recent COVID-19 vaccination should be considered reactive in the first instance, occurring owing to stimulation of the immune system. A clinical follow-up according to the patient’s risk profile without further diagnostic measures is justified. In the case of preexisting unilateral cancer, vaccination should be given contralaterally whenever possible. Persistently enlarged lymph nodes should be re-evaluated (2 to) 6 weeks after the second dose, with additional diagnostic tests tailored to the clinical context. Fine needle aspiration is a well established, safe, rapid and cost-effective method to investigate an underlying malignancy, especially metastasis. Recording vaccination history, including date of injection, site and vaccine type, as well as communicating this information to treating physicians of different specialties is paramount for properly handling COVID-19 vaccine-associated lymphadenopathy.

Radiological and clinicopathological findings of breast cancer during the COVID-19 pandemic: a comparative study with the pre-pandemic era.

PURPOSE: The diagnosis and surgical treatment delays that occurred during the coronavirus disease-2019- (COVID-19) pandemic may have affected breast cancer presentation. This study aimed to determine whether there was a difference in the clinicopathological characteristics of breast cancers during the pandemic by comparing them with similar cases from the previous year. The study also aimed to determine the radiological findings of breast cancers during the pandemic. METHODS: A retrospective review was made of patients who underwent surgery for breast cancer between March 11, 2020, and December 11, 2020 (the pandemic group). These patients were compared with similar patients from the previous year (the pre-pandemic group). The postoperative histopathology results of both groups were compared, and the preoperative radiological findings of the pandemic group were defined. RESULTS: There were 71 patients in the pandemic group and 219 patients in the pre-pandemic group. The tumor size was significantly greater, lymph node involvement was more frequent, and waiting time for surgery was longer in the pandemic group (P < 0.001, P = 0.044, P = 0.001, respectively). There was no significant difference between the groups in respect of in situ/invasive tumor distribution, histological type and histological grade of tumor, the presence of lymphovascular/perineural invasion, multifocal/multicentric focus, and Breast Imaging Reporting and Data System Classification (P > 0.15). The radiologic findings of breast cancer during the pandemic typically showed characteristics of malignancy. CONCLUSION: Patients diagnosed with breast cancer during the COVID-19 pandemic had larger tumor sizes, more frequent lymph node involvement and longer waiting time for surgical treatment. Screening programs should be continued as soon as possible by taking necessary precautions.

Is advanced bipolar v anced bipolar vessel sealing de essel sealing device really eff eally effective in decreasing the pelvic lymphocele ratio in open surgery for endometrial cancer?

BACKGROUND: We aim to show pelvic lymphocele (PL) rates in patients who were operated for endometrial cancer (EC) and underwent systematic paraaortic bilateral pelvic lymph node dissection (PABPLND) with advanced bipolar vessel sealing device (ABVSD). METHODS: The medical files of all patients who underwent open surgery for EC between January 2017 and December 2021 were retrospectively analyzed. One hundred three patients who operated with the diagnosis of high-intermediate and high-risk endometrial cancer were included. Systematic PABPLND was performed with total abdominal hysterectomy with or without bilateral salpingo-oophorectomy during surgery to all patients. All operations were performed by same three surgeons who were expert in their field. While the lymph packages were removed during surgical dissection, the distal afferent and proximal efferent lymphatic channels were sealed with LigaSure™ blunt tip sealer/divider (Medtronic, Covidien, USA). The patients were scanned with computed tomography (CT) between 8 and 12 weeks postoperatively. Lymphocele diagnosis was confirmed by radiologists and largest diameter was recorded. Clinical-pathological findings of all patients were recorded. RESULTS: Mean age and body mass index (BMI) of all participants were 58.6 ±10.2 years and 28.1± 5.6 kg/m2 . The most histopathological findings were endometrioid type (84.5%) and grade 2 (44.2%) ECs. The pelvic lymphocele (PL) was detected with CT in 24 of 103 patients at 8 to 12 weeks postoperatively. Only two PL patients were symptomatic. The first patient had symptoms of pelvic fullness and compression while the second patient had infected image. PL was located to right pelvic area in first case while the second was located on the vaginal cuff. DISCUSSION: The dissection and sealing of major lymph vessels were achieved during the removal of all lymph packages with LigaSure™ blunt tip laparoscopic sealer/divider. The use of advanced bipolar systems can reduce the formation of PL in lymph node dissection in endometrial cancer.

Contrast-enhanced Ultrasound Using Intradermal Microbubble Sulfur Hexafluoride for Identification of Sentinel Lymph Nodes During Breast Cancer Surgery: A Clinical Trial.

BACKGROUND/AIM: Sentinel lymph node (SLN) procedures have gained popularity in early breast cancer thanks to the reduction of surgical side-effects. The standard SLN mapping procedure uses 99mTc-nanocolloid human serum albumin with/without blue dye; limitations include logistical challenges and adverse reactions. Recently, contrast-enhanced ultrasound (CEUS) using sulfur hexafluoride has emerged as a promising technique for SLN mapping. Our study aimed to compare the CEUS technique with the standard isotope method. MATERIALS AND METHODS: AX-CES, a prospective, monocentric, single-arm phase-3 study was designed (EudraCT: 2020-000393-20). Inclusion criteria were histologically diagnosed early breast cancer eligible for upfront surgery and SLN resection, bodyweight 40-85 kg, and no prior history of ipsilateral surgery or radiotherapy. All patients underwent CEUS prior to surgery and blue dye injection was performed in areas with contrast accumulation. After the experimental procedure, all patients underwent the standard mapping procedure and SLN frozen section assessment was performed. Data on the success rate, systemic reactions, mean procedure time, CEUS appearance, SLN number, and concordance with standard mapping procedure were collected. RESULTS: Among 16 cases, a median of two SLNs were identified during CEUS. In all cases, at least one SLN was identified by CEUS (100%). In six cases, SLNs were classified during CEUS as abnormal, which was confirmed by definitive staining in four cases. After the standard mapping technique, in 15 out of the 16 cases (87.50%), at least one SLN from the standard mapping procedure was marked with blue dye in the CEUS procedure. In our series, sensitivity and specificity of SLN detection by CEUS were 75% and 100%, respectively. CONCLUSION: CEUS is a safe and manageable intraoperative procedure. When compared with standard techniques, US appearance during CEUS may provide additional information when associated with histological assessment.

SARS-CoV-2-fertozés okozta Kikuchi-Fujimoto-betegség sikeres gyógyítása.

The Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis) is an autolimited process, which can be caused by viral agents like Epstein-Barr virus, human herpes virus, HIV, B19 parvovirus, paromyxoviruses, SARS-CoV-2, Toxoplasma and Yersinia. The correct diagnosis is based on histological findings. A 45-year-old female patient presented in our ambulatory room with a unilateral neck mass, fever, dysphonia and dysphagia. The patient was double-tested positive for SARS-CoV-2 approximately 1 month before the symptoms started. Before examination, the nasopharyngeal rapid test for SARS-CoV-2 resulted negative. After hospitalization, intravenous antibiotic (Augmentin, 3 × 1.2 g; Klion, 2 × 100 mg) and steroid (Solu-Medrol, 2 × 125 mg) therapy were administered. The neck and chest CT described a right-sided retropharyngeal abscess with bilateral neck lympadenopathy. Urgent tracheotomy, neck dissection and lymph node biopsy were made. The intraoperative findings excluded the presence of the abscess. The histological findings confirmed the necrotizing histiocytic lymphadenitis. Despite of the fact that the Kikuchi-Fujimoto disease is autolimited, we can see that, in this particular case, the lymphadenopathy after the SARS-CoV-2 infection caused a life-threatening situation. The formed extratissular liquid imitated the image of a retropharyngeal abscess. In the searched worldwide literature, similar intervention for this type of process was not described. Tracheotomy, neck dissection and removing the lymph nodes as ,,trigger zones" caused the full recovery of the patient. In the future, we consider important proving and clarifying the correlation between SARS-CoV-2 and Kikuchi-Fujimoto disease. Orv Hetil. 2022; 163(27): 1061-1065.

Persons with HIV Develop Spike-Specific Lymph Node Germinal Center Responses following SARS-CoV-2 Vaccination.

COVID-19 disproportionately affects persons with HIV (PWH) in worldwide locations with limited access to SARS-CoV-2 vaccines. PWH exhibit impaired immune responses to some, but not all, vaccines. Lymph node (LN) biopsies from PWH demonstrate abnormal LN structure, including dysregulated germinal center (GC) architecture. It is not clear whether LN dysregulation prevents PWH from mounting Ag-specific GC responses in the draining LN following vaccination. To address this issue, we longitudinally collected blood and draining LN fine needle aspiration samples before and after SARS-CoV-2 vaccination from a prospective, observational cohort of 11 PWH on antiretroviral therapy: 2 who received a two-dose mRNA vaccine series and 9 who received a single dose of the Ad26.COV2.S vaccine. Following vaccination, we observed spike-specific Abs, spike-specific B and T cells in the blood, and spike-specific GC B cell and T follicular helper cell responses in the LN of both mRNA vaccine recipients. We detected spike-specific Abs in the blood of all Ad26.COV2.S recipients, and one of six sampled Ad26.COV2.S recipients developed a detectable spike-specific GC B and T follicular helper cell response in the draining LN. Our data show that PWH can mount Ag-specific GC immune responses in the draining LN following SARS-CoV-2 vaccination. Due to the small and diverse nature of this cohort and the limited number of available controls, we are unable to elucidate all potential factors contributing to the infrequent vaccine-induced GC response observed in the Ad26.COV2.S recipients. Our preliminary findings suggest this is a necessary area of future research.

18F-Fluciclovine-Avid Axillary Lymph Nodes After COVID-19 Vaccination on PET/CT for Suspected Recurrence of Prostate Cancer.

Abnormally increased 18F-FDG avidity of axillary lymph nodes has become a frequent diagnostic dilemma on PET/CT in the current climate of global vaccinations directed against severe acute respiratory syndrome coronavirus 2. This avidity is due to the inflammatory response evoked by vaccines and the nonspecific nature of 18F-FDG uptake, which is increased in both malignant and inflammatory processes. Similarly, 18F-fluciclovine, an amino acid analog indicated for the assessment of biochemical recurrence of prostate cancer, may also demonstrate nonspecific inflammatory uptake. We report a case of 18F-fluciclovine PET/CT obtained for concern about prostate cancer. In this case, isolated avid lymph nodes were seen in the left axilla. A screening questionnaire revealed that the patient had recently received the second dose of the Pfizer-BioNTech coronavirus disease 2019 vaccine in his left shoulder, and hence, the uptake was determined to be reactive.

Influence of circadian clocks on adaptive immunity and vaccination responses.

The adaptive immune response is under circadian control, yet, why adaptive immune reactions continue to exhibit circadian changes over long periods of time is unknown. Using a combination of experimental and mathematical modeling approaches, we show here that dendritic cells migrate from the skin to the draining lymph node in a time-of-day-dependent manner, which provides an enhanced likelihood for functional interactions with T cells. Rhythmic expression of TNF in the draining lymph node enhances BMAL1-controlled ICAM-1 expression in high endothelial venules, resulting in lymphocyte infiltration and lymph node expansion. Lymph node cellularity continues to be different for weeks after the initial time-of-day-dependent challenge, which governs the immune response to vaccinations directed against Hepatitis A virus as well as SARS-CoV-2. In this work, we present a mechanistic understanding of the time-of-day dependent development and maintenance of an adaptive immune response, providing a strategy for using time-of-day to optimize vaccination regimes.

Eosinophilic lymph node abscesses following a COVID-19 vaccination: A case report.

In this paper, we reported a 37-year-old man who developed several lymphadenopathies after using the second dose of Pfizer-BioNtech vaccination against SARS-CoV-2. The excisional lymph node biopsy showed eosinophil-rich inflammation with micro-abscesses. Although eosinophilic dermatosis and eosinophilic myocarditis have been described previously following COVID-19 vaccinations, eosinophilic lymph node abscess was not reported in the literature. In our case, all lesions were completely recovered with steroid treatment. The patient has been doing well and no recurrence has been observed for six months.

The location of unilateral axillary lymphadenopathy after COVID-19 vaccination compared with that of metastasis from breast cancer without vaccination.

PURPOSE: Unilateral axillary lymphadenopathy is known to occur after coronavirus disease (COVID-19) vaccination. Post-vaccination lymphadenopathy may mimic the metastatic lymph nodes in breast cancer, and it is challenging to distinguish between them. This study investigated whether the localization of axillary lymphadenopathy on magnetic resonance imaging (MRI) could be used to distinguish reactive lymphadenopathy after COVID-19 vaccines from metastatic nodes. MATERIALS AND METHODS: We retrospectively examined preoperative MRI images of 684 axillae in 342 patients who underwent breast cancer surgery from June to October 2021. Lymphadenopathy was defined as cortical thickening or short axis ≥ 5 mm. The axilla was divided into ventral and dorsal parts on the axial plane using a perpendicular line extending from the most anterior margin of the muscle group, including the deltoid, latissimus dorsi, or teres major muscles, relative to a line along the lateral chest wall. We recorded the presence or absence of axillary lymphadenopathy in each area and the number of visible lymph nodes. RESULTS: Of 80 axillae, 41 and 39 were included in the vaccine and metastasis groups, respectively. The median time from the last vaccination to MRI was 19 days in the vaccine group. The number of visible axillary lymph nodes was significantly higher in the vaccine group (median, 15 nodes) than in the metastasis group (7 nodes) (P < 0.001). Dorsal lymphadenopathy was observed in 16 (39.0%) and two (5.1%) axillae in the vaccine and metastasis groups, respectively (P < 0.001). If the presence of both ventral and dorsal lymphadenopathy is considered indicative of vaccine-induced reaction, this finding has a sensitivity of 34.1%, specificity of 97.4%, and positive and negative predictive values of 93.3％ and 58.5%, respectively. CONCLUSION: The presence of deep axillary lymphadenopathy may be an important factor for distinguishing post-vaccination lymphadenopathy from metastasis. The number of axillary lymph nodes may also help.

Multispectral optoacoustic tomography to differentiate between lymph node metastases and coronavirus-19 vaccine-associated lymphadenopathy.

INTRODUCTION: Worldwide mass vaccination for COVID-19 started in late 2020. COVID-19 vaccines cause benign hypermetabolic lymphadenopathies. Clinical stratification between vaccine-associated benign lymphadenopathies and malignant lymphadenopathies through ultrasound, MRI or FDG PET-CT is not feasible. This leads to unnecessary lymph node biopsies, excisions and even radical lymph node dissections. Therefore, to avoid unnecessary surgeries, we assessed whether noninvasive multispectral optoacoustic tomography (MSOT) enables a better differentiation between benign and malignant lymphadenopathies. PATIENTS AND METHODS: All patients were vaccinated for COVID-19. We used MSOT to image deoxy- and oxyhaemoglobin levels in lymph nodes of tumour patients to assess metastatic status. MSOT imaging results were compared with standard ultrasound and pathological lymph node analysis. We also evaluated the influences of gender, age and time between vaccination and MSOT measurement of lymph nodes on the measured deoxy- and oxyhaemoglobin levels in patients with reactive lymph node changes. RESULTS: Multispectral optoacoustic tomography was able to identify cancer-free lymph nodes in vivo without a single false negative (33 total lymph nodes), with 100% sensitivity and 50% specificity. A statistically significant higher deoxyhaemoglobin content was detected in patients with tumour manifestations in the lymph node (p = 0.02). There was no statistically significant difference concerning oxyhaemoglobin (p = 0.65). Age, sex and time between vaccination and MSOT measurement had statistically non-significant impact on deoxy- and oxyhaemoglobin levels in patients with reactive lymph nodes. CONCLUSION: Here, we show that MSOT measurement is an advantageous clinical approach to differentiate between vaccine-associated benign lymphadenopathy and malignant lymph node metastases based on the deoxygenation level in lymph nodes.

Prevalence of Adenopathy at Chest Computed Tomography After Vaccination for Severe Acute Respiratory Syndrome Coronavirus 2.

OBJECTIVE: This study aimed to determine the prevalence of axillary and subpectoral (SP) lymph nodes after ipsilateral COVID-19 vaccine administration on chest computed tomography (CT). METHODS: Subjects with chest CTs between 2 and 25 days after a first or second vaccine dose, December 15, 2020, to February 12, 2021, were included. Orthogonal measures of the largest axillary and SP nodes were recorded by 2 readers blinded to vaccine administration and clinical details. A mean nodal diameter discrepancy of ≥6 mm between contralateral stations was considered positive for asymmetry. Correlation with the side of vaccination, using a Spearman rank correlation, was performed on the full cohort and after excluding patients with diseases associated with adenopathy. RESULTS: Of the 138 subjects (81 women, 57 men; mean [SD] age, 74.4 ± 11.7 years), 48 (35%) had asymmetrically enlarged axillary and/or SP lymph nodes, 42 (30%) had ipsilateral, and 6 (4%) had contralateral to vaccination ( P = 0.003). Exclusion of 29 subjects with conditions associated with adenopathy showed almost identical correlation, with asymmetric nodes in 32 of 109 (29%) ipsilateral and in 5 of 109 (5%) contralateral to vaccination ( P = 0.002). CONCLUSIONS: Axillary and/or SP lymph nodes ipsilateral to vaccine administration represents a clinical conundrum. Asymmetric nodes were detected at CT in 30% of subjects overall and 29% of subjects without conditions associated with adenopathy, approximately double the prevalence rate reported to the Centers for Disease Control and Prevention by vaccine manufacturers. When interpreting examinations correlation with vaccine administration timing and site is important for pragmatic management.

Evaluation of metabolic changes in FDG PET/CT imaging after mRNA-based COVID-19 vaccination.

BACKGROUND: It isimportant to evaluate the vaccine-related metabolic changes on FDG PET/CT to avoid confusing results. We here aimed to assess the frequency and intensity of regional and systemic metabolic PET/CT changes of patients who received the mRNAbased COVID-19 vaccine (BNT162b2-Pfizer/BioNTech) and to analyze possible factors affecting these changes. METHODS: Among the patients who underwent FDG PET/CT for any indication in our department between July 2021 and December 2021, 129 volunteer patients with a history of COVID-19 vaccination were included in this prospective observational study. Bilateral axillary lymph nodes, ipsilateral deltoid muscle, bone marrow, spleen, thyroid, and liver FDG uptakes were evaluated visually and semiquantitatively for each examination. RESULTS: The frequencies of positive axillary lymph nodes after vaccination were 40%, 44.4%, 32.6%, and 44.7% in all, 1st dose, 2nd dose, and heterologous vaccination regimens groups, respectively. Maximum standardized uptake values of spleen, liver, and bone marrow were statistically high in patients with positive axillary lymph nodes than with negative ones (p < 0.05). Positive deltoid muscle uptake and diffusely increased thyroid uptake findings were observed in 10 and 8 patients, respectively. The median time interval between vaccination and imaging was 9.5 days for patients with positive axillary lymph nodes and 17 days for patients with negative nodes. In our study group, only 8 patients had a positive documented history of COVID-19 infection. DISCUSSION: Regional and systemic metabolic changes were occasionally found on FDG PET/CT imaging in patients who received the mRNA-based COVID-19 vaccine. To avoid these timely decreasing changes, we recommend managing the ideal timing of imaging or vaccination and taking a careful history.

Multisystem Inflammatory Syndrome in Adults Accompanied with Kikuchi-Fujimoto Disease.

We herein report a case of multisystem inflammatory syndrome in adults (MIS-A) complicated with Kikuchi-Fujimoto disease (KFD). A previously healthy 41-year-old man presented with painful swelling of the cervical lymph nodes, fever, diarrhea, conjunctivitis, edema, and hypotension one month after the onset of asymptomatic coronavirus disease 2019. Laboratory investigations revealed an elevation of CRP, and echocardiography indicated diastolic dysfunction. We diagnosed the patient to have MIS-A. Histopathology of the lymph nodes showed necrotizing lymphadenitis. After the initiation of hydrocortisone and diuretics, his symptoms resolved immediately. This case suggested that post-viral immune dysregulation in MIS-A could play a role in the etiology of KFD.

Novel intraoperative near-infrared imaging strategy to identify abnormalities in the anterior mediastinum.

Thoracic surgeons are frequently asked to biopsy suspicious tissues in the anterior mediastinum to discriminate between a reactive versus malignant pathology such as lymph nodes. The most common benign cause of a mediastinal lymph node is a reactive lymph node from a prior infection or inflammatory process such as post-COVID or granulomatous disease. The most common malignant cause is a lymphoproliferative disorder but also metastatic disease from neck, breast and other regional cancers. Biopsies in this location are challenging because they are far from the trachea and the sternum is a barrier to most diagnostic procedures. Thus, a surgical biopsy is frequently required and a common procedure for Thoracic surgeons. Technically, identifying these lesions can be challenging, particularly for small lesions or those in patients with high body mass index. In order to improve contrast between diseased tissue in the anterior mediastinum and surrounding adipose tissue, we have been studying near-infrared imaging during surgery using indocyanine green (ICG) to give contrast to the abnormal tissues and to avoid an unnecessary extended resection. We developed a modified technique to give ICG to a patient during a biopsy in the anterior mediastinum to specifically highlight abnormal tissues. As a proof-of-principle, we present a case of a young woman with a suspicious 2 cm mediastinal lymph node that required surgical biopsy.

CEST MRI and MALDI imaging reveal metabolic alterations in the cervical lymph nodes of EAE mice.

BACKGROUND: Multiple sclerosis (MS) is a neurodegenerative disease, wherein aberrant immune cells target myelin-ensheathed nerves. Conventional magnetic resonance imaging (MRI) can be performed to monitor damage to the central nervous system that results from previous inflammation; however, these imaging biomarkers are not necessarily indicative of active, progressive stages of the disease. The immune cells responsible for MS are first activated and sensitized to myelin in lymph nodes (LNs). Here, we present a new strategy for monitoring active disease activity in MS, chemical exchange saturation transfer (CEST) MRI of LNs. METHODS AND RESULTS: We studied the potential utility of conventional (T2-weighted) and CEST MRI to monitor changes in these LNs during disease progression in an experimental autoimmune encephalomyelitis (EAE) model. We found CEST signal changes corresponded temporally with disease activity. CEST signals at the 3.2 ppm frequency during the active stage of EAE correlated significantly with the cellular (flow cytometry) and metabolic (mass spectrometry imaging) composition of the LNs, as well as immune cell infiltration into brain and spinal cord tissue. Correlating primary metabolites as identified by matrix-assisted laser desorption/ionization (MALDI) imaging included alanine, lactate, leucine, malate, and phenylalanine. CONCLUSIONS: Taken together, we demonstrate the utility of CEST MRI signal changes in superficial cervical LNs as a complementary imaging biomarker for monitoring disease activity in MS. CEST MRI biomarkers corresponded to disease activity, correlated with immune activation (surface markers, antigen-stimulated proliferation), and correlated with LN metabolite levels.