Emerging Evidence of IgG4-Related Disease in Pericarditis: A Systematic Review

Introduction Immunoglobulin G4-related disease (IgG4-RD) is a recently identified immune-mediated condition that is debilitating and often overlooked. While IgG4-RD has been reported in several organs, this study reviews cases where IgG4-RD caused pericarditis. Methods A systematic search was conducted from inception until March 1, 2025. All age groups and both sexes with confirmed pericarditis were included, along with the following inclusion criteria: 1) Patients with pericardial biopsy showing IgG4/IgG ratio of >40%. 2) Patients with pericardial biopsy revealing IgG4/HPF of >10. 3) Patients who had confirmed IgG4-RD from other organ biopsies through IgG4 staining, or diagnostic imaging suggestive of IgG4-RD, or pericardial biopsy with classic IgG4-RD histopathologic patterns, with elevated serum IgG4 levels, provided no other diagnosis was more likely. Results A total of 50 patients were included, with a mean age of 64.86±15.79 years. There were 36 (72%) males. The most common presenting symptom was dyspnea in 27 (54%) patients. Different pericardial involvements were reported, including pericardial thickening 37 (74%), constrictive pericarditis 28 (56%), pericardial effusion 23 (46%), pericardial calcification 6 (12%), and pericardial nodule 5 (10%). In 28 (56%) patients, only the pericardium was affected. In addition to the pericardium, eight (16%) patients had one other organ affected, and 11 (22%) patients had two additional organs affected. Two (4.5%) cases ended in demise. Conclusion Although rare, IgG4-RD can cause pericarditis, leading to pericardial thickening, effusion, constrictive pericarditis, or the formation of pericardial nodules. Treatment with corticosteroids or pericardiectomy has been associated with favorable outcomes. Introduction Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated, fibroinflammatory condition that affects multiple organs in the body. It is a slowly progressing and often debilitating disease, with the potential to be fatal in some cases [1]. The condition was first suspected in the pancreas where a subset of autoimmune pancreatitis was associated with elevated levels of serum IgG4, now termed autoimmune pancreatitis type I [2]. The discovery that individuals with autoimmune pancreatitis also develop extra-pancreatic fibroinflammatory lesions containing abundant IgG4-bearing cells, in addition to histopathological features consistent with that in the pancreas, which include; dense lymphoplasmacytic infiltration, storiform fibrosis, and either obliterative or non-obliterative phlebitis, contributed to the establishment of the concept of IgG4-RD as a unique clinical entity in 2003 [1-3]. For decades, conditions such as Riedel thyroiditis, sclerosing cholangitis, Mikulicz’s syndrome, hypertrophic pachymeningitis, and retroperitoneal fibrosis were considered distinct entities. However, they are now classified within the spectrum of IgG4-RD, as they have been found to share similar histologic features and present concurrently in some patients [4]. The worldwide prevalence and incidence of IgG4-RD are mostly underreported. Still, studies from Japan have revealed that the incidence of autoimmune pancreatitis increased from 0.8 to 3.1 cases per 100,000 people between 2007 and 2016, suggesting a swift rise in recognition of IgG4-RD within just a decade [4]. There is a higher prevalence among males, with the average age at diagnosis typically ranging from the fifth to sixth decade of life. However, classic presentations have also been documented in pediatric patients [1]. Cigarette smoking is the only well-documented modifiable risk factor associated with the development of IgG4-RD [5]. A genome-wide association study revealed that the FC-γ receptor IIb and HLA-DRB1 regions were associated with an increased susceptibility to IgG4-RD, indicating a potential genetic predisposition to its pathogenesis [6]. The pathophysiology of IgG4-RD remains incompletely understood. However, several critical components have been identified, including the migration of activated B cells to the site of inflammation, where they facilitate the expansion and differentiation of T cells into CD4+ cytotoxic T lymphocytes (CTLs). These CD4+ CTLs subsequently induce apoptosis by releasing perforins and granzymes. In response, activated M2 macrophages clear the apoptotic cells while also contributing to the activation of fibroblasts. This activation is promoted through several mediators, including IFN-γ (interferon-gamma), TGF-β (transforming growth factor-beta), and IL-1 (interleukin-1) from CD4+ CTLs, along with PDGF (platelet-derived growth factor) from activated B cells, and various factors from macrophages. As fibroblasts become activated, they secrete extracellular matrix proteins, leading to tissue remodeling and fibrosis. Over time, the progressive expansion of the extracellular matrix and increased cell proliferation contribute to the development of tumor-like masses and the subsequent enlargement of affected organs, as observed in clinical settings [7]. While IgG4-RD has been reported in multiple organs, this study is the first to comprehensively review cases where it affects the pericardium, leading to pericarditis. Methods Study design The present systematic review was conducted per the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Literature search A thorough systematic search was conducted across Scopus, PubMed, Web of Science, and Google Scholar databases to retrieve studies published from inception until March 1, 2025. The search employed the following keywords: “IgG4 OR IgG4RD OR immunoglobulin AND pericarditis OR tamponade OR pericardial OR pericardium OR serositis OR serosal” Eligibility criteria The inclusion criteria were restricted to English-language publications involving only human subjects, specifically case-control studies, cohort studies, cross-sectional studies, or case reports. Additionally, due to the limited number of studies on this topic, conference papers containing adequate information were also included. All age groups, both sexes, with confirmed pericarditis through a combination of clinical examination, ECG (electrocardiography), diagnostic imaging (including echocardiography, magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET)), laboratory investigations, or histopathological examination of the pericardial tissue or fluid were included. Given the limited number of reports on this entity and a lack of standardized diagnostic criteria for IgG4-RD pericarditis, such as an established IgG4/IgG ratio or IgG4/high power field (HPF) in pericardial specimens or its necessity in the first place when other clues are suggestive of this disease, this review adopted an inclusive approach. With patients of either of the following criteria being included: 1) Patients with pericardial biopsy showing an IgG4/IgG ratio of >40% or reported as “increased”. 2) Patients with pericardial biopsy revealing IgG4/HPF of >10 or reported as “increased”. 3) Patients who had confirmed IgG4-RD from other organ biopsies through IgG4 staining, or diagnostic imaging suggestive of IgG4-RD, or pericardial biopsy with classic IgG4-RD histopathologic patterns, with elevated serum IgG4 levels, provided no other diagnosis was more likely. The exclusion criteria included studies with incomplete information about the patients or the method of diagnosis. Patients who were more likely to have pericarditis due to causes other than IgG4-RD. Studies from journals with inadequate peer review and questionable reliability were excluded [8]. Study selection The screening process commenced with two independent researchers who systematically reviewed the titles and abstracts of all identified studies. Following this initial assessment, a comprehensive full-text evaluation was conducted based on predefined inclusion and exclusion criteria. Studies that satisfied these eligibility criteria were subsequently selected for inclusion. In instances where disagreements emerged between the two researchers, a third author was consulted to mediate and resolve conflicts through discussion and consensus. Data items Data extraction was conducted using Microsoft Office Excel 2016. The following variables were collected for each study: first author’s name, year of publication, study design, country of origin, sample size, patient sex, age, past medical and surgical history, family history, presenting complaint, and duration of symptoms. Additionally, data regarding pericardial involvement were extracted, including the presence of pericardial thickening, constrictive physiology, pericardial calcification, and pericardial nodules. The presence or absence of pleural disease was also recorded. If available, findings from diagnostic imaging modalities such as chest radiography, echocardiography, CT, MRI, PET, and right heart catheterization were documented. Laboratory results, when reported, were extracted for C-reactive protein (CRP), Erythrocyte sedimentation rate (ESR), N-terminal pro-brain natriuretic peptide (NT-proBNP), serum IgG4 levels, serum IgG4/IgG ratio, and any other notable laboratory parameters. Furthermore, the number of organs affected by IgG4-RD, and the histopathological findings were collected. Treatment modalities, including both successful and unsuccessful interventions, were documented, along with follow-up duration and clinical outcomes. Data analysis The data were analyzed using the Statistical Package for Social Sciences (SPSS) version 26.0, which facilitated the quantitative synthesis of the information. Relevant variables were displayed in summary tables, with categorical data represented by frequency and percentage, and quantitative data summarized using the mean and standard deviation. Results Study selection The literature search yielded 87 studies from the databases. During the initial screening, one study was removed due to duplication, four for being in a non-English language, and four were closed access/unretrievable. The 78 studies remained for screening through titles and abstracts. Of these, eleven were excluded from the title and three from the abstract due to irrelevancy. During the full-text screening, two retrospective cohort studies were excluded even though they included patients with IgG4-RD causing pericarditis. As those studies also included patients with IgG4-RD affecting other organs without pericardial involvement. However, they did not provide specific details on the characteristics, diagnostic workup, or histopathological findings of IgG4-RD in the subset of patients with pericarditis. As a result, they did not meet the inclusion criteria for this systematic review. One study was excluded as there was insufficient information to diagnose IgG4-RD. Additionally, two other studies were excluded after the full-text screening because they did not report IgG4-RD as a cause of pericarditis. Letters to the editor and preprints were excluded, with six and one paper removed respectively. Two studies were excluded from journals with inadequate peer review. Ultimately a total of 50 studies were included in the current systematic review for analysis (Figure 1). Characteristics of the studies Of the included studies, 40 (80%) were case reports, and ten (20%) were conference abstracts. Japan 22 (44%) and the United States of America 17 (34%) had the most publications, followed by Korea 3 (6%), the other studies were all from different countries (Table 1, Table 2, Table 3) [9-58]. Table 1. Demographics and clinical presentations of patients. Author Year Country Study type No. cases Age (y) Sex Presenting complaint Duration PMH Pleural disease Pericardial manifestations Extra-pericardial IgG4-RD organ involvement Khodabandeh et al. [9] 2010 USA P 1 54 M Dyspnea N/A No Yes Thickening, constrictive pericarditis No Horie et al. [10] 2012 USA P 1 76 M Dyspnea, peripheral edema 24 N/A Yes Thickening, constrictive pericarditis No Kabara et al. [11] 2012 Japan C 1 69 M Peripheral edema 12 N/A Yes Pericardial effusion No Sekiguchi et al. [12] 2012 USA C 1 29 F Dyspnea, chest pain 60 N/A Yes Thickening, constrictive pericarditis Pleural thickening Sekiguchi et al. [13] 2012 USA C 1 76 M Dyspnea, peripheral edema 24 N/A Yes Thickening, constrictive pericarditis No Kassier et al. [14] 2014 USA P 1 75 M Peripheral edema N/A N/A No Thickening, constrictive pericarditis, effusion, calcification No Morita et al. [15] 2014 Japan C 1 60 F Referred for cardiac tamponade N/A N/A No Thickening, effusion, tamponade Lacrimal and parotid glands, mediastinal lymph nodes Seo et al. [16] 2014 Korea C 1 58 M Dyspnea, fatigue 0.25 Cancer Yes Constrictive pericarditis No Yanagi et al. [17] 2014 Japan C 1 81 M Dyspnea, peripheral edema, anorexia N/A HTN Yes Thickening, constrictive pericarditis No Matsumiya et al. [18] 2015 Japan C 1 50 F Chest pain, fever, fatigue 1 Asthma Yes Thickening Mediastinal lymph nodes Mori et al. [19] 2015 Japan C 1 65 M Nausea, abdominal pain 0.1 Dyslipidemia No Thickening Pancreas, biliary system Sendo et al. [20] 2015 Japan C 1 78 F Dyspnea N/A HTN, pulmonary tuberculosis, asthma No Thickening, effusion Pancreas, multiple lymph nodes Horie et al. [21] 2016 Japan C 1 73 M Dyspnea 2 HTN, DM Yes Thickening, constrictive pericarditis, effusion No Hourai et al. [22] 2016 Japan C 1 75 M Incidental finding N/A HD Yes Thickening, effusion Mediastinal lymph nodes, coronary artery Ibe et al. [23] 2016 Japan C 1 72 M Dyspnea, weight loss 1 No Yes Thickening, constrictive pericarditis, effusion, nodule on the pericardium No Kondo et al. [24] 2016 Japan C 1 78 M Peripheral edema, elevated liver enzymes 24 N/A Yes Thickening, constrictive pericarditis, Pleural thickening/plaques, sclerosing cholangitis Moreno et al. [25] 2016 Spain C 1 70 M Dyspnea 12 HTN, dyslipidemia, HD, COPD, CML, aortitis Yes Pericardial effusion Aorta, bilateral renal sinus fat Terzic et al. [26] 2017 Serbia C 1 53 M Fatigue 12 N/A No Thickening, constrictive pericarditis, effusion, calcification Retroperitoneum Matsuda et al. [27] 2018 Japan C 1 70 F Bilateral lacrimal gland enlargement 24 N/A No Pericarditis Coronary artery, lacrimal glands, retroperitoneum, pancreas and right common iliac artery, ascending aorta Steiner et al. [28] 2018 USA P 1 78 M Dyspnea, peripheral edema, ascites N/A N/A Yes Thickening, constrictive pericarditis, calcification, pericardial mass No Weiss et al. [29] 2018 USA C 1 83 M Incidental finding N/A Cancer, constrictive pericarditis, pericardial effusion, HD No Thickening, constrictive pericarditis No Arao et al. [30] 2019 Japan C 1 64 F Abdominal fulness 1 HTN, Asthma No Pericardial effusion Ureteral wall Gorecka et al. [31] 2019 Ireland C 1 53 F Weight loss, chest pain, fatigue 6 No Yes Thickening, effusion No Sly et al. [32] 2019 USA P 1 37 M Chest pain N/A N/A No Thickening, effusion No Tomoda et al. [33] 2019 Japan C 1 72 F Dyspnea N/A N/A No Pericarditis, nodules on pericardium Mediastinal lymph nodes Wang et al. [34] 2019 China P 1 80 M Dyspnea 3 N/A Yes Thickening, constrictive pericarditis, calcification. No Yassi et al. [35] 2019 USA C 1 36 M Chest pain N/A No No Thickening, constrictive pericarditis No Meier et al. [36] 2020 USA C 1 78 M Acute respiratory failure N/A Recurrent pericardial and pleural effusion Yes Pericardial effusion Aorta, retroperitoneal fibrosis Yamamoto et al. [37] 2020 Japan C 1 75 M Incidental finding N/A DM, HD, dementia No Thickening, pericardial nodule, effusion No Yuriditsky et al. [38] 2020 USA C 1 79 M Dyspnea N/A HD, recurrent pleural effusion Yes Thickening, constrictive pericarditis, pericardial calcification No Corona-Rodarte et al. [39] 2021 Mexico C 1 44 M Cough, peripheral edema, dyspnea, weight loss, fever 4 N/A Yes Constrictive pericarditis, effusion No Doumen et al. [40] 2021 Belgium C 1 76 F Dyspnea, cough 2 DM, HTN, COPD, dyslipidemia Yes Pericarditis No Fujita et al. [41] 2021 Japan C 1 83 M Dyspnea, weight gain 0.25 N/A Yes Thickening, constrictive pericarditis No Majid et al. [42] 2022 USA C 1 54 M Dyspnea, peripheral edema, chest pain, fatigue N/A HTN No Thickening, constrictive pericarditis No Maltes et al. [43] 2022 Portugal C 1 68 M Peripheral edema, ascites N/A HD No Thickening, constrictive pericarditis No Ohman et al. [44] 2022 USA P 1 51 F Jaundice, ascites, weight loss N/A Asthma No Thickening, constrictive pericarditis Omentum, uterus George et al. [45] 2023 USA P 1 41 M Vomiting, weight loss, dyspnea 12 N/A No Thickening, constrictive pericarditis No Kawanami et al. [46] 2023 Japan C 1 66 M Refractory pericarditis N/A N/A Yes Thickening, effusion, pericardial nodule Aortic root, coronary arteries Lildar et al. [47] 2023 USA P 1 79 M Dyspnea N/A Cancer, chronic pancreatitis No Pericardial effusion Pancreas, multiple lymph nodes Saad et al. [48] 2023 Egypt C 1 13 F Dyspnea, hemoptysis, fever, weight loss 2 N/A Yes Thickening, effusion Lungs Sugawara et al. [49] 2023 Japan C 1 67 F Chest pain, palpitation N/A DM, Asthma No Pericardial effusion Submandibular gland Wei et al. [50] 2023 Japan C 1 82 F Chest pain, abdominal fullness 8 N/A Yes Pericardial effusion Submandibular glands, pharyngeal tonsils An et al. [51] 2024 Korea C 1 66 F Dyspnea, peripheral edema 0.5 N/A Yes Thickening, constrictive pericarditis, effusion No Miura et al. [52] 2024 Japan C 1 72 M Incidental finding N/A N/A No Thickening, effusion Aorta, coronary artery, submandibular gland Okabe et al. [53] 2024 Japan C 1 82 M Peripheral edema, sialadenitis 3 DM, HD, idiopathic exophthalmos Yes Constrictive pericarditis, calcification Salivary glands, orbit Ozgur et al. [54] 2024 USA C 1 55 M Dyspnea, peripheral edema, hemoptysis, weight loss 6 DM Yes Thickening, constrictive pericarditis No Shimada et al. [55] 2024 Japan C 1 72 M Scrotal edema, ascites N/A HTN Yes Thickening, constrictive pericarditis Aorta Son et al. [56] 2024 Korea C 1 77 M Anorexia, fever 3 HTN, dyslipidemia Yes Thickening, effusion No Thummala et al. [57] 2024 USA P 1 51 M Dyspnea N/A HD, CKD No Thickening, constrictive pericarditis No Ono et al. [58] 2025 Japan C 1 67 M Dyspnea, peripheral edema, anorexia 6 Liver dysfunction Yes Thickening, constrictive pericarditis No M: Male, F: Female, DM: Diabetes mellitus, HTN: Hypertension, CKD: Chronic liver disease, HD: Heart disease, COPD: Chronic obstructive lung disease, CML: Chronic myeloid leukemia, USA: United States of America, P: Conference abstracts, C: Case report, N/A: Not available. Table 2. Radiological, electrocardiography, and heart catheterization findings of the cases. Author X-ray Echocardiography CT Cardiac MRI PET-CT ECG Right heart catheterization Khodabandeh et al. [9] N/A Constrictive physiology, pericardial thickening Pericardial thickening, bilateral pleural effusion N/A N/A N/A Constrictive physiology Horie et al. [10] Bilateral pleural effusion Constrictive physiology N/A Suggestive of constrictive pericarditis N/A N/A Constrictive physiology Kabara et al. [11] Cardiomegaly Collapsed left atrium, pleural effusion Pericardial effusion, retroperitoneal fibrosis N/A N/A N/A N/A Sekiguchi et al. [12] Bilateral lung opacities Constrictive physiology Pericardial thickening, bilateral pleural thickening, right-sided pleural effusion N/A N/A N/A N/A Sekiguchi et al. [13] Bilateral pleural effusion Constrictive physiology N/A Constrictive physiology N/A N/A Constrictive physiology Kassier et al. [14] N/A Pericardial thickening, pericardial effusion, pericardial calcification N/A Pericardial thickening, pericardial delayed hyperenhancement N/A Atrial flutter Constrictive physiology Morita et al. [15] Cardiomegaly Pericardial thickening Pericardial thickening N/A N/A Normal sinus rhythm N/A Seo et al. [16] Bilateral pleural effusion, cardiomegaly Constrictive physiology, pericardial effusion N/A N/A Pericardial effusion N/A N/A Yanagi et al. [17] Bilateral pleural effusion Pericardial thickening, constrictive physiology Pericardial thickening Constrictive physiology, pericardial thickening N/A Sinus rhythm, low-voltage QRS complexes Constrictive physiology Matsumiya et al. [18] Normal Pericardial thickening Pericardial thickening, left-sided pleural effusion, mediastinal lymphadenopathy N/A Patchy uptake in the pericardium, and a dense uptake in the mediastinal lymph node Normal sinus rhythm N/A Mori et al. [19] Normal Normal Pericardial thickening, pancreatic parenchyma enlargement, common bile duct wall thickening N/A N/A Normal sinus rhythm N/A Sendo et al. [20] Cardiomegaly Pericardial effusion Pericardial effusion, lymphadenopathies in the mediastinum, para-aorta, abdominal cavity, and inguinal region. diffuse enlargement of the pancreas, and bilateral hydronephrosis. N/A N/A N/A N/A Horie et al. [21] Bilateral pleural effusion, cardiomegaly Pericardial effusion N/A N/A Localized uptake in the pericardium N/A Constrictive physiology Hourai et al. [22] Cardiomegaly, bilateral pleural effusion N/A Pericardial thickening, pericardial effusion, and thickening of the perivascular regions of the abdominal aorta N/A Enhanced uptake in mediastinal lymph nodes, pericardium, and perivascular regions of the abdominal aorta and aortic wall N/A N/A Ibe et al. [23] Bilateral pleural effusion Constrictive physiology, pericardial effusion N/A Constrictive physiology, pericardial thickening, pericardial effusion, enhancement of pericardium N/A N/A Constrictive physiology Kondo et al. [24] N/A N/A N/A N/A Bilateral pleural effusion, thickening of the pleuro-pericardial wall, and accumulation in the right pleura N/A Constrictive physiology Moreno et al. [25] N/A Pericardial effusion Pericardial effusion, bilateral pleural effusion, aortitis, and bilateral obliteration of renal sinus fat N/A N/A N/A N/A Terzic et al. [26] Cardiomegaly Pericardial effusion Pericardial effusion, retroperitoneal fibrosis N/A N/A Sinus rhythm, low-voltage QRS complexes N/A Matsuda et al. [27] N/A N/A Left circumflex artery wall thickening N/A Uptake in left ventricular wall, left circumflex artery wall, and ascending aorta. e findings suggested dacryoadenitis, retroperitoneal fibromatosis, pancreatic periarteritis, and right common iliac periarteritis. N/A N/A Steiner et al. [28] N/A Constrictive physiology, anterior pericardial mass Pericardial thickening, pericardial calcification, pericardial nodule, bilateral pleural effusion N/A N/A N/A Not definitive for constrictive physiology Weiss et al. [29] N/A N/A N/A N/A N/A N/A N/A Arao et al. [30] Cardiomegaly Pericardial effusion Pericardial effusion, ureteral wall thickening N/A N/A Sinus rhythm, low-voltage QRS complexes N/A Gorecka et al. [31] Bilateral pleural effusion Pericardial effusion, mild impairment of left ventricular function and moderate mitral regurgitation N/A Pericardial thickening, and active inflammation of the pericardium N/A N/A N/A Sly et al. [32] N/A Constrictive physiology, pericardial effusion Pericardial effusion N/A N/A Diffuse ST elevations and PR depression. Constrictive physiology Tomoda et al. [33] N/A Pericardial effusion Pericardial thickening, mediastinal lymphadenopathy N/A N/A N/A N/A Wang et al. [34] N/A N/A Pericardial thickening, bilateral pleural effusion, ascites N/A N/A N/A Constrictive physiology Yassi et al. [35] N/A N/A N/A N/A N/A Changes consistent with acute pericarditis N/A Meier et al. [36] N/A N/A Pericardial effusion, right-sided pleural effusion, aortitis, pulmonary embolism, retroperitoneal fibrosis. N/A N/A N/A N/A Yamamoto et al. [37] N/A N/A Pericardial thickening, pericardial nodules, and pericardial and paraphrenic lymph node enlargement Pericardial thickening, pericardial effusion, with inhomogeneous gadolinium enhancement Metabolic activity in the pericardial nodular lesions Normal sinus rhythm Normal Yuriditsky et al. [38] N/A Constrictive physiology Pericardial thickening, right-sided pleural effusion Constrictive physiology N/A Sinus rhythm, incomplete right bundle branch block and a left anterior fascicular block Constrictive physiology Corona-Rodarte et al. [39] N/A Constrictive physiology, pericardial effusion Prevascular, and pretracheal mediastinal lymphadenopathies, bilateral pleural effusion, atelectasis, pericardial effusion with contrast enhancement of the pericardium Suggestive of constrictive pericarditis N/A N/A N/A Doumen et al. [40] Bilateral pleural effusion, cardiomegaly Pericardial effusion Normal after treatment Pericardial effusion, pericardial thickening Unspecified pericardial uptake Sinus rhythm, incomplete right bundle branch block N/A Fujita et al. [41] Bilateral pleural effusion, cardiomegaly Pericardial thickening, constrictive physiology Pericardial thickening, pericardial effusion Adhesion between pericardium and myocardium N/A Sinus rhythm, low-voltage QRS complexes Constrictive physiology Majid et al. [42] N/A Constrictive physiology, pericardial effusion N/A Pericardial effusion, constrictive physiology, marked pericardial delayed enhancement N/A N/A N/A Maltes et al. [43] N/A Pericardial thickening, constrictive physiology Pericardial thickening, an anomalous pulmonary venous return Pericardial thickening with diffuse late gadolinium enhancement N/A N/A Constrictive physiology Ohman et al. [44] N/A Constrictive physiology Hepatomegaly, thickening of the uterus, and omentum Constrictive physiology, pericardial thickening N/A N/A N/A George et al. [45] N/A Pericardial thickening, and myocardial-pericardial tethering of left ventricle apical segments Pericardial thickening Constrictive physiology N/A N/A Constrictive physiology Kawanami et al. [46] N/A Pericardial effusion, a hyperechoic lesion around the aortic root, and multiple nodules in the pericardium Pericardial thickening. contrast-enhancing nodules along the pericardium and soft tissue around the aortic root, coronary artery, and dorsal left atrium N/A Focal uptake consistent with the lesions detected by contrast-enhanced CT Normal sinus rhythm N/A Lildar et al. [47] N/A Pericardial effusion with early diastolic RV collapse, suggestive of cardiac tamponade Pancreatic calcification consistent with chronic pancreatitis and fluid localized to the tail suggesting acute uncomplicated pancreatitis N/A N/A Electrical alternans N/A Saad et al. [48] N/A N/A Pericardial thickening, pericardial effusion, left pleural basal thickening in addition to bilateral patchy areas of pulmonary interstitial thickening (consolidation) and ground glass veiling N/A N/A N/A N/A Sugawara et al. [49] N/A N/A Pericardial effusion N/A Uptake in the pericardium and submandibular gland Sinus tachycardia N/A Wei et al. [50] N/A Pericardial effusion Pericardial effusion, bilateral pleural effusion N/A Pericardial effusion corresponds to an increased area of uptake. Bilateral pharyngeal tonsil, submandibular gland, small lymph nodes in the right side of sternal bone and mediastinum and the wall of ascending aorta Sinus rhythm, low T-wave N/A An et al. [51] N/A Constrictive physiology, pericardial effusion Pericardial thickening, pericardial effusion, and left-sided pleural effusions N/A Patchy uptake in the pericardium Sinus rhythm, low-voltage QRS complexes N/A Miura et al. [52] N/A N/A Pericardial thickening, pericardial effusion N/A N/A N/A N/A Okabe et al. [53] N/A Constrictive physiology Pericardial calcification N/A N/A Atrial fibrillation Constrictive physiology Ozgur et al. [54] Right-sided pleural effusion. Constrictive physiology N/A Pericardial thickening with increased enhancement on delayed myocardial enhancement N/A Normal sinus rhythm Constrictive phys