Right ventricular (18)F-FDG uptake is an important indicator for cardiac involvement in patients with suspected cardiac sarcoidosis

Extrapulmonary sarcoidosis

Sarcoidosis is a chronic disease of unknown origin that develops when a genetically susceptible host is exposed to an antigen, leading to an exuberant immune response characterized by granulomatous inflammation. Although lung involvement is almost universal as well as the leading cause of morbidity and mortality, virtually any organ can be affected. In particular, sarcoidosis of the heart, nervous system, and eyes can be devastating, leading to death, debilitation and blindness, and a multidisciplinary approach involving expert specialists is required for prompt diagnosis and appropriate treatment. Sarcoidosis of the skin can be disfiguring, thus posing a substantial psychologic and social impact on the patients. The diagnosis is often straightforward in the presence of compatible clinical manifestations in patients with biopsy-proven sarcoidosis, but is challenging when extrapulmonary signs/symptoms occur in isolation. Corticosteroids remain the first line therapy, with immunosuppressive or biologic agents being reserved to patients failing or experiencing side effects from steroids or developing refractory disease.

Syncope in an Otherwise Healthy 74-Year-Old Woman

CASE PRESENTATION

A 74-year-old woman with a history of hypertension and peripheral artery disease and a reported diagnosis of sarcoidosis presents for an episode of syncope and shortness of breath. She had a history of sarcoidosis diagnosed on chest radiography that showed lymphadenopathy. There were no associated symptoms, and she was not previously treated for sarcoidosis. She previously smoked and had quit smoking 9 years earlier.

Management of cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a form of inflammatory cardiomyopathy associated with significant clinical complications such as high-degree atrioventricular block, ventricular tachycardia, and heart failure as well as sudden cardiac death. It is therefore important to provide an expert consensus statement summarizing the role of different available diagnostic tools and emphasizing the importance of a multidisciplinary approach. By integrating clinical information and the results of diagnostic tests, an accurate, validated, and timely diagnosis can be made, while alternative diagnoses can be reasonably excluded. This clinical expert consensus statement reviews the evidence on the management of different CS manifestations and provides advice to practicing clinicians in the field on the role of immunosuppression and the treatment of cardiac complications based on limited published data and the experience of international CS experts. The monitoring and risk stratification of patients with CS is also covered, while controversies and future research needs are explored.

Prednisone vs methotrexate in treatment naïve cardiac sarcoidosis

BACKGROUND

Side effects limit the long-term use of glucocorticoids in cardiac sarcoidosis (CS), and methotrexate has gained attention as steroid sparing agent although the supporting evidence is poor. This study compared prednisone monotherapy, methotrexate monotherapy or a combination of both, in the reduction of myocardial Fluorine-18 fluorodeoxyglucose (FDG) uptake and clinical stabilization of CS patients.

METHODS AND RESULTS

In this retrospective cohort study, 61 newly diagnosed and treatment naïve CS patients commenced treatment with prednisone (N = 21), methotrexate (N = 30) or prednisone and methotrexate (N = 10) between January 2010 and December 2017. Primary outcome was metabolic response on FDG PET/CT and secondary outcomes were treatment patterns, major adverse cardiovascular events, left ventricular ejection fraction, biomarkers and side effects. At a median treatment duration of 6.2 [5.7-7.2] months, 71.4% of patients were FDG PET/CT responders, and the overall myocardial maximum standardized uptake value decreased from 6.9 [5.0-10.1] to 3.4 [2.1-4.7] (P < 0.001), with no significant differences between treatment groups. During 24 months of follow-up, 7 patients (33.3%; prednisone), 6 patients (20.0%; methotrexate) and 1 patient (10.0%; combination group) experienced at least one major adverse cardiovascular event (P = 0.292). Left ventricular ejection fraction was preserved in all treatment groups.

CONCLUSIONS

Significant suppression of cardiac FDG uptake occurred in CS patients after 6 months of prednisone, methotrexate or combination therapy. There were no significant differences in clinical outcomes during follow-up. These results warrant further investigation of methotrexate treatment in CS patients.

The Role of Echocardiography in the Contemporary Diagnosis and Prognosis of Cardiac Sarcoidosis: A Comprehensive Review

Cardiac sarcoidosis (CS) is a rare inflammatory disorder characterised by the presence of non-caseating granulomas within the myocardium. Contemporary studies have revealed that 25-30% of patients with systemic sarcoidosis have cardiac involvement, with detection rates increasing in the era of advanced cardiac imaging. The use of late gadolinium enhancement cardiac magnetic resonance and 18fluorodeoxy glucose positron emission tomography (FDG-PET) imaging has superseded endomyocardial biopsy for the diagnosis of CS. Echocardiography has historically been used as a screening tool with abnormalities triggering the need for advanced imaging, and as a tool to assess cardiac function. Regional wall thinning or aneurysm formation in a noncoronary distribution may indicate granuloma infiltration. Thinning of the basal septum in the setting of extracardiac sarcoidosis carries a high specificity for cardiac involvement. Abnormal myocardial echotexture and eccentric hypertrophy may be suggestive of active myocardial inflammation. The presence of right-ventricular involvement as indicated by free-wall aneurysms can mimic arrhythmogenic right-ventricular cardiomyopathy. More recently, the use of myocardial strain has increased the sensitivity of echocardiography in diagnosing cardiac involvement. Echocardiography is limited in prognostication, with impaired left-ventricular (LV) ejection fraction and LV dilatation being the only established independent predictors of mortality. More research is required to explore how advanced echocardiographic technologies can increase both the diagnostic sensitivity and prognostic ability of this modality in CS.

Diagnostic Accuracy of Cardiac MRI versus FDG PET for Cardiac Sarcoidosis: A Systematic Review and Meta-Analysis

Background There is limited consensus regarding the relative diagnostic performance of cardiac MRI and fluorodeoxyglucose (FDG) PET for cardiac sarcoidosis. Purpose To perform a systematic review and meta-analysis to compare the diagnostic accuracy of cardiac MRI and FDG PET for cardiac sarcoidosis. Materials and Methods Medline, Ovid Epub, Cochrane Central Register of Controlled Trials, Embase, Emcare, and Scopus were searched from inception until January 2022. Inclusion criteria included studies that evaluated the diagnostic accuracy of cardiac MRI or FDG PET for cardiac sarcoidosis in adults. Data were independently extracted by two investigators. Summary accuracy metrics were obtained by using bivariate random-effects meta-analysis. Meta-regression was used to assess the effect of different covariates. Risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2 tool. The study protocol was registered a priori in the International Prospective Register of Systematic Reviews (Prospero protocol CRD42021214776). Results Thirty-three studies were included (1997 patients, 687 with cardiac sarcoidosis); 17 studies evaluated cardiac MRI (1031 patients) and 26 evaluated FDG PET (1363 patients). Six studies directly compared cardiac MRI and PET in the same patients (303 patients). Cardiac MRI had higher sensitivity than FDG PET (95% vs 84%; P = .002), with no difference in specificity (85% vs 82%; P = .85). In a sensitivity analysis restricted to studies with direct comparison, point estimates were similar to those from the overall analysis: cardiac MRI and FDG PET had sensitivities of 92% and 81% and specificities of 72% and 82%, respectively. Covariate analysis demonstrated that sensitivity for FDG PET was highest with quantitative versus qualitative evaluation (93% vs 76%; P = .01), whereas sensitivity for MRI was highest with inclusion of T2 imaging (99% vs 88%; P = .001). Thirty studies were at risk of bias. Conclusion Cardiac MRI had higher sensitivity than fluorodeoxyglucose PET for diagnosis of cardiac sarcoidosis but similar specificity. Limitations, including risk of bias and few studies with direct comparison, necessitate additional study. © RSNA, 2022 Online supplemental material is available for this article.

Advances in Diagnostic Imaging for Cardiac Sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology, and its clinical presentation depends on the affected organ. Cardiac sarcoidosis (CS) is one of the leading causes of death among patients with sarcoidosis. The clinical manifestations of CS are heterogeneous, and range from asymptomatic to life-threatening arrhythmias and progressive heart failure due to the extent and location of granulomatous inflammation in the myocardium. Advances in imaging techniques have played a pivotal role in the evaluation of CS because histological diagnoses obtained by myocardial biopsy tend to have lower sensitivity. The diagnosis of CS is challenging, and several approaches, notably those using positron emission tomography and cardiac magnetic resonance imaging (MRI), have been reported. Delayed-enhanced computed tomography (CT) may also be used for diagnosing CS in patients with MRI-incompatible devices and allows acceptable evaluation of myocardial hyperenhancement in such patients. This article reviews the advances in imaging techniques for the evaluation of CS.

The Role of Multimodality Imaging in Cardiac Sarcoidosis

The etiology and the progression of sarcoidosis remain unknown. However, cardiac sarcoidosis (CS) is significantly associated with a poor prognosis due to the associated congestive heart failure, arrhythmias (such as an advanced atrioventricular block), and ventricular tachyarrhythmia. Novel imaging modalities are now available to detect CS lesions secondary to active inflammation, granuloma formation, and fibrotic changes. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and cardiac magnetic resonance imaging (CMR) play essential roles in diagnosing and monitoring patients with confirmed or suspected CS. The following focused review will highlight the emerging role of non-invasive cardiac imaging techniques, including FDG PET/CT and CMR.

Prognostic value of phase analysis on gated single photon emission computed tomography in patients with cardiac sarcoidosis

BACKGROUND

We aimed to determine the correlation between phase analysis, reflecting the heterogeneity of perfusion defects, and the dyssynchrony of the left ventricle wall motion, and adverse cardiac events in cardiac sarcoidosis (CS) patients.

METHODS

Fifty-seven consecutive patients with diagnosed CS (64 [IQR 55-71] years old, 14 males), who underwent 18F-FDG PET/CT and ECG-gated SPECT, were studied. FDG PET was analysed to measure cardiac metabolic volume (CMV), and total lesion glycolysis (TLG). The SPECT findings, such as LVEF, Summed Rest Score (SRS), bandwidth (BW) were evaluated.

RESULTS

The median of BW was 56° (IQR 40-95). BW showed a strong inverse correlation with LVEF (r = - 0.60, P < 0.0001), and positive correlation with SRS (r = 0.82, P < 0.0001). However, there were no significant correlations between BW and CMV or TLG. The Kaplan-Meier curves revealed a significantly higher rate of MACE in the high BW group (BW > 56°) than the low BW group (BW ≤ 56°) (15.1%/years vs. 4.4%/years, P = 0.025). In multivariable analysis, BW was a significant independent predictor of MACE (P = 0.015).

CONCLUSION

Phase analysis on gated SPECT was a significant and independent predictor of MACE in patients with CS.

Diagnostic performance of F-18 FDG PET for detection of cardiac sarcoidosis; A systematic review and meta-analysis

OBJECTIVE

The purpose of the current study was to investigate the diagnostic performance of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for diagnosis of cardiac sarcoidosis (CS) through a systematic review and meta-analysis.

METHODS

The PubMed and EMBASE database, from the earliest available date of indexing through 31 March 31, 2018, were searched for studies evaluating the diagnostic performance of F-18 FDG PET or PET/CT for CS. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic (SROC) curves.

RESULTS

Across 17 studies (891 patients), the pooled sensitivity was 0.84 [95% confidence interval (95% CI) 0.71-0.91] with heterogeneity (I2 = 77.5) and a pooled specificity of 0.83 (95% CI 0.74-0.89) with heterogeneity (I2 = 80.0). Likelihood ratio (LR) syntheses gave an overall LR+ of 4.9 (95% CI 3.3-7.3) and LR- of 0.2 (95% CI 0.11-0.35). The pooled diagnostic odds ratio was 27 (95% CI 14-55). Hierarchical SROC curve indicates that the area under the curve was 0.90 (95% CI 0.87-0.92). Meta-regression showed that combined myocardial perfusion imaging was the source of heterogeneity.

CONCLUSION

The current meta-analysis showed the moderate sensitivity and specificity of F-18 FDG PET or PET/CT for diagnosis of CS. The presence of combined myocardial perfusion imaging could improve diagnostic accuracy of F-18 FDG PET or PET/CT for diagnosis of CS. At present, the literature regarding the use of F-18 FDG PET for detection of CS remains limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of F-18 FDG PET for diagnosis of CS.

18F-FDG uptake of the right ventricle is an important predictor of histopathologic diagnosis by endomyocardial biopsy in patients with cardiac sarcoidosis

BACKGROUND

The aim of this study was to determine whether right ventricle (RV) 18F-fluorodeoxyglucose (FDG) uptake can predict positive findings of endomyocardial biopsy (EMB) in patients with cardiac sarcoidosis (CS).

METHODS

70 consecutive patients with clinically diagnosed CS who had undergone FDG PET were registered in the present study. Patients without EMB (n = 42) were excluded. Ultimately, 28 patients were studied. EMB samples were obtained from the RV septum. We evaluated the FDG uptake on six segments (RV, left ventricle anterior, septal, lateral, inferior, and apex).

RESULTS

Positive EMB was found in six patients (21%). Patients were divided into two groups according to positive (n = 12 [43%]) or negative (n = 16 [57%]) RV FDG uptake. Patients with positive RV FDG uptake had a significantly higher frequency of positive EMB than those without (42% vs. 6%, P = 0.024). On the other hand, there was no EMB-predictive value for the FDG uptakes in the other five segments, the cardiac metabolic volume, total lesion glycolysis, left ventricular ejection fraction, or any electrocardiogram findings.

CONCLUSIONS

FDG uptake of the RV but no other heart segment was associated with positive EMB in CS patients. The presence of RV FDG uptake could improve the rate of positive EMB up to 42% in patients with CS.

Lower left ventricular ejection fraction and higher serum angiotensin-converting enzyme activity are associated with histopathological diagnosis by endomyocardial biopsy in patients with cardiac sarcoidosis

BACKGROUND

The histopathological diagnosis of cardiac sarcoidosis (CS) is challenging because of sampling error in endomyocardial biopsy (EMB) and the determinants of positive EMB are unclear. Reduced left ventricular ejection fraction (LVEF) is a simple parameter of the extent of myocardial damage, and higher serum angiotensin-converting enzyme (ACE) activity would indicate the spread of disease activity in CS patients. Thus, we sought to examine whether these parameters are related to the histopathological diagnosis of CS by EMB.

METHODS

A total of 94 consecutive clinically diagnosed CS patients between August 1986 and March 2019 who were admitted to two academic hospitals were examined. We determined EMB as positive if non-caseating epithelioid granulomas were confirmed in the myocardial tissue. Patients were divided into two groups according to positive (n = 37) and negative (n = 57) EMB. We assessed the relationship between LVEF, serum ACE activity and positive EMB.

RESULTS

Multivariable analysis revealed that both LVEF and serum ACE were independently associated with positive EMB (OR 0.83, 95% CI 0.70-0.99; OR 1.39, 95% CI 1.02-1.90, respectively). Moreover, patients with both lower LVEF (<37%, median) and higher ACE activity (≥13.5 IU/L, median) had the highest frequency of positive EMB (p = .003). The combination of lower LVEF and higher serum ACE showed better specificity (91.2%) and positive predictive value (73.7%) than either LVEF or serum ACE alone for positive EMB.

CONCLUSIONS

Lower LVEF and higher serum ACE activity were associated with positive EMB, suggesting that these parameters might be useful for predicting positive EMB in CS patients.

Right Ventricular Abnormalities on Cardiovascular Magnetic Resonance Imaging in Patients With Sarcoidosis

OBJECTIVES

This study aimed to determine the prevalence on cardiac magnetic resonance (CMR) of right ventricular (RV) systolic dysfunction and RV late gadolinium enhancement (LGE), their determinants, and their influences on long-term adverse outcomes in patients with sarcoidosis.

BACKGROUND

In patients with sarcoidosis, RV abnormalities have been described on many imaging modalities. On CMR, RV abnormalities include RV systolic dysfunction quantified as an abnormal right ventricular ejection fraction (RVEF), and RV LGE.

METHODS

Consecutive patients with biopsy-proven sarcoidosis who underwent CMR for suspected cardiac involvement were studied. They were followed for 2 endpoints: all-cause death, and a composite arrhythmic endpoint of sudden cardiac death or significant ventricular arrhythmia.

RESULTS

Among 290 patients, RV systolic dysfunction (RVEF <40% in men and <45% in women) and RV LGE were present in 35 (12.1%) and 16 (5.5%), respectively. The median follow-up time was 3.2 years (interquartile range [IQR]: 1.6 to 5.7 years) for all-cause death and 3.0 years (IQR: 1.4 to 5.5 years) for the arrhythmic endpoint. On Cox proportional hazards regression multivariable analyses, only RVEF was independently associated with all-cause death (hazard ratio [HR]: 1.05 for every 1% decrease; 95% confidence interval [CI]: 1.01 to 1.09; p = 0.022) after adjustment for left ventricular EF, left ventricular LGE extent, and the presence of RV LGE. RVEF was not associated with the arrhythmic endpoint (HR: 1.01; 95% CI: 0.96 to 1.06; p = 0.67). Conversely, RV LGE was not associated with all-cause death (HR: 2.78; 95% CI: 0.36 to 21.66; p = 0.33), while it was independently associated with the arrhythmic endpoint (HR: 5.43; 95% CI: 1.25 to 23.47; p = 0.024).

CONCLUSIONS

In this study of patients with sarcoidosis, RV systolic dysfunction and RV LGE had distinct prognostic associations; RV systolic dysfunction but not RV LGE was independently associated with all-cause death, whereas RV LGE but not RV systolic dysfunction was independently associated with sudden cardiac death or significant ventricular arrhythmia. These findings may indicate distinct implications for the management of RV abnormalities in sarcoidosis.

18-FDG-PET in a patient cohort suspected for cardiac sarcoidosis: Right ventricular uptake is associated with pathological uptake in mediastinal lymph nodes

INTRODUCTION

In up to 65% of cardiac sarcoidosis patients, the disease is confined to the heart. Diagnosing isolated cardiac sarcoidosis is challenging due to the low sensitivity of endomyocardial biopsy. If cardiac sarcoidosis is part of biopsy-confirmed systemic sarcoidosis, the diagnosis can be based on cardiac imaging studies. We compared the imaging features of patients with isolated cardiac FDG uptake on positron emission tomography with those who had findings indicative of systemic sarcoidosis.

MATERIALS AND METHODS

137 consecutive cardiac FDG-PET/CT studies performed on subjects suspected of having cardiac sarcoidosis were retrospectively analyzed.

RESULTS

33 patients had pathological left ventricular FDG uptake, and 12 of these also had pathological right ventricular uptake. 16/33 patients with pathological cardiac uptake had pathological extracardiac uptake. 10/12 patients with both LV- and RV-uptake patterns had extracardiac uptake compared to 6/21 of those with pathological LV uptake without RV uptake. SUVmax values in the myocardium were higher among patients with abnormal extracardiac uptake. The presence of extracardiac uptake was the only imaging-related factor that could predict a biopsy indicative of sarcoidosis.

CONCLUSION

Right ventricular involvement seems to be more common in patients who also have findings suggestive of suspected systemic sarcoidosis, compared with patients with PET findings indicative of isolated cardiac disease.

The role of positron emission tomography in the assessment of cardiac sarcoidosis

The myocardium and the cardiovascular system are often involved in patients with sarcoidosis. As therapy should be started as early as possible to avoid complications such as left ventricular dysfunction, a prompt and reliable diagnosis by means of non-invasive tests would be highly warranted. Among other techniques, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has emerged as a high sensitive tool to detect sites of inflammation before morphological changes are visible to conventional imaging techniques. We therefore aim at summarizing the most relevant findings in the literature on the use of 18F-fluorodeoxyglucose PET in the diagnostic workup of cardiac sarcoidosis and to underline future perspectives.

Diagnosing complications and co-morbidities of fibrotic interstitial lung disease

Introduction: Interstitial lung diseases (ILDs) represent a heterogeneous group of rare disorders that include more than 200 entities, mostly associated with high mortality. In recent years, the progress regarding the understanding of the pathogenesis of these diseases led to the approval of specific treatments. In ILDs, the presence of comorbidities has a significant impact on the quality of life and the survival of patients and, therefore, their diagnosis and treatment has a pivotal role in management and could improve overall outcome. Areas covered: We discuss key diagnostic issues with regard to the most frequent comorbidities in ILDs. Treatment options are also discussed as the decision to investigate more definitively in order to identify specific comorbidities (including lung cancer, pulmonary hypertension, GE reflux, and obstructive sleep apnoea) is critically dependent upon whether comorbidity-specific treatments are likely to be helpful in individual patients, judged on a case by case basis. Expert opinion: The extent to which clinicians proactively pursue the identification of comorbidities depends on realistic treatment goals in individual patients.

18F-FDG-PET in Finnish patients with clinical suspicion of cardiac sarcoidosis: Female sex and history of atrioventricular block increase the prevalence of positive PET findings

INTRODUCTION

Fluorodeoxyglucose positron emission tomography (FDG-PET) is a non-invasive imaging modality that has been shown to be a feasible method to demonstrate myocardial inflammation. The aim of this study was to identify the patients suspected of having cardiac sarcoidosis (CS), who are most likely to benefit from PET imaging.

MATERIALS AND METHODS

137 patients suspected of having CS underwent a dedicated cardiac FDG-PET examination at Tampere University Hospital between August 2012 and September 2015. These examinations were retrospectively analyzed.

RESULTS

33 and 12 of the 137 patients had abnormal left and right ventricular (LV and RV) FDG-uptake, respectively. Abnormal LV-uptake and RV-uptake were significantly associated with female sex and a history of advanced AV-block (P < 0.05). Abnormal RV-uptake was also associated with ventricular tachycardia and atrial fibrillation (P < 0.05). 56% of the 27 female patients with a history of AV-block had a pathological PET finding compared to only 6% of the 49 male patients without a history of AV-block. There were 17 female patients with history of both AV-block and ventricular tachycardia, 71% of them had abnormal PET finding.

CONCLUSIONS

Abnormal FDG-PET findings were associated with female sex, AV-block, and arrhythmias in this clinical cohort.

Multimodality Cardiac Imaging for the Assessment of Left Atrial Function and the Association With Atrial Arrhythmias

Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function at the current moment. Numerous studies, however, have shown that functional measures may be superior to the maximal LA volume in several aspects and to possess clinical value even in the absence of structural abnormalities. Such functional measures could prove particularly useful in the setting of predicting atrial fibrillation, which will be a point of focus in this review. Pivotal cardiac magnetic resonance imaging studies have revealed high correlation between LA fibrosis and risk of atrial fibrillation recurrence after catheter ablation, and subsequent multimodality imaging studies have uncovered an inverse relationship between LA reservoir function and degree of LA fibrosis. This has sparked an increased interest into the application of advanced imaging modalities, including both speckle tracking echocardiography and tissue tracking by cardiac magnetic resonance imaging. Even though increasing evidence has supported the use of functional measures and proven its superiority to the maximal LA volume, they have still not been adopted in clinical guidelines. The reason for this discrepancy may rely on the fact that there is little to no agreement on how to technically perform deformation analysis of the LA. Such technical considerations, limitations, and alternate imaging prospects will be addressed in this review.

Comorbidities in interstitial lung diseases

Fibrosing lung disorders include a large number of diseases with diverse behaviour. Patients can die because of the progression of their illness, remain stable or even improve after appropriate treatment has been instituted. Comorbidities, such as acute and chronic infection, gastro-oesophageal reflux, pulmonary hypertension, lung cancer, cardiovascular diseases, and obstructive sleep apnoea, can pre-exist or develop at any time during the course of the disease and, if unidentified and untreated, may impair quality of life, impact upon the respiratory status of the patients, and ultimately lead to disease progression and death. Therefore, early identification and accurate treatment of comorbidities is essential.

Severe Sarcoidosis

In sarcoidosis, reduction in mortality and the prevention of disability due to major organ involvement are treatment goals. Thus, it is important to recognize severe disease and identify patients at higher risk of progression to severe disease. In this article, fibrotic lung disease and cardiac sarcoidosis are reviewed as the major contributors to sarcoidosis mortality and morbidity. In the absence of a standardized definition of severe pulmonary disease, a multidisciplinary approach to clinical staging is suggested, based on symptoms, pulmonary function tests, and imaging findings at presentation, integrated with the duration of disease and longitudinal disease behavior during early follow-up.

Advances in radionuclide imaging of cardiac sarcoidosis

INTRODUCTION

Radionuclide imaging for the diagnosis and monitoring of cardiac involvement in sarcoidosis has advanced significantly in recent years.

SOURCES OF DATA

This article is based on published clinical guidelines, literature review and our collective clinical experience.

AREAS OF AGREEMENT

Gallium-67 scintigraphy is among the diagnostic criteria for cardiac involvement in systemic sarcoidosis, and it is strongly associated with response to treatment. However, fluorine-18, 2-fluoro-deoxyglucose (FDG) positron emission tomography (PET) is now preferred both for diagnosis and for assessing prognosis.

AREAS OF CONTROVERSY

Most data are from small observational studies that are potentially biased.

GROWING POINTS

Quantitative imaging to assess changes in disease activity in response to treatment may lead to FDG-PET having an important routine role in managing cardiac sarcoidosis.

AREAS TIMELY FOR DEVELOPING RESEARCH

Larger prospective studies are required, particularly to assess the effectiveness of radionuclide imaging in improving clinical management and outcome.

Incidence of abnormal positron emission tomography in patients with unexplained cardiomyopathy and ventricular arrhythmias: The potential role of occult inflammation in arrhythmogenesis

BACKGROUND

The incidence of myocardial inflammation in patients with unexplained cardiomyopathy referred for ventricular arrhythmias (VAs) is unknown.

OBJECTIVE

The purpose of this study was to report fasting positron emission tomographic (PET) scan findings in consecutive patients referred with unexplained cardiomyopathy and VA.

METHODS

Fluorine-18 fluoro-2-deoxyglucose (18-FDG) PET/computed tomographic (CT) scans with a >16-hour fasting protocol were prospectively ordered for patients referred for VA and unexplained cardiomyopathy (ejection fraction <55%). Patients with focal myocardial FDG uptake were labeled as arrhythmogenic inflammatory cardiomyopathy (AIC) and classified into 4 groups based on the presence of lymph node uptake (AIC+) and perfusion abnormalities (early vs late stage).

RESULTS

Over a 3-year period, 103 PET scans were performed, with 49% (AIC+ 17, AIC 33) exhibiting focal FDG uptake. Mean patient age was 52 ± 12 years (ejection fraction 36% ± 16%). Patients with AIC were more likely to have a history of pacemaker (32% vs 6%, P = .002) compared to those with normal PET. When biopsy was performed, histologic diagnosis revealed nongranulomatous inflammation in 6 patients and sarcoidosis in 18 patients. Ninety percent of patients with AIC/AIC+ were prescribed immunosuppressive therapy, and 58% underwent ablation. Correlation between low voltage regions on electroanatomic mapping and FDG uptake was observed in 74%. Magnetic resonance imaging findings matched abnormal PET regions in only 40%.

CONCLUSION

Nearly 50% of patients referred with unexplained cardiomyopathy and VA demonstrate ongoing focal myocardial inflammation on FDG PET. These data suggest that a significant proportion of patients labeled "idiopathic" may have occult AIC, which may benefit from early detection and immunosuppressive medical therapy.

Current status of nuclear cardiology in Japan: Ongoing efforts to improve clinical standards and to establish evidence

Nuclear cardiology imaging tests are widely performed in Japan as clinical practice. The Japanese nuclear cardiology community has developed new diagnostic imaging tests using (123)I-beta-methyl-p-iodophenyl-pentadecanoic acid, (123)I-metaiodobenzylguanidine, and (18)F-fluorodeoxyglucose PET for detecting cardiac involvement in sarcoidosis. These tests have become popular worldwide. The Japanese Circulation Society and the Japanese Society of Nuclear Cardiology have published clinical imaging guidelines showing indications and standards for the new imaging tests. JSNC is currently striving to improve the standard of clinical practice and is promoting research activities.

Historical transition of management of sarcoidosis

Sarcoidosis is a systemic granulomatous disease of undetermined etiology, and it primarily affects the lungs and lymphatic system but may involve other organs. Recently, there have been several new insights in Japanese patients. The frequency of cardiac, ocular, and cutaneous sarcoidosis has increased in Japan, whereas, the proportion of patients with bilateral hilar lymphadenopathy decreased from 1960 to 2004. Propionibacterium acnes (P. acnes) has been studied extensively as one of the causative microorganism for granuloma formation, particularly in Japan. P. acnes-specific monoclonal antibodies are useful for diagnosing sarcoidosis. The potential association between smoking and sarcoidosis has been evaluated in a Japanese study, which found a higher prevalence of sarcoidosis among young smokers than that in previous reports. Recently, ¹⁸F-fluorodeoxyglucose positron-emission tomography, which permits visualization of activated inflammation, and endobronchial ultrasonography-guided transbronchial needle aspiration have been increasingly used to diagnose sarcoidosis. Cardiac sarcoidosis is found to be the main cause of death in Japan. The 2006 revised Japanese guidelines for diagnosing cardiac sarcoidosis are useful, particularly for subclinical cardiac sarcoidosis patients. Further studies and international communication and evaluation are needed to determine the causes of sarcoidosis, identify the risk factors for progressive disease, and develop new and effective treatments.