Positron emission tomography predicted recovery of complete A-V nodal dysfunction in a patient with cardiac sarcoidosis

FDG-PET/CT and rest myocardial perfusion imaging to predict high-degree atrioventricular block recovery in cardiac sarcoidosis

BACKGROUNDS

High-degree atrioventricular block (AVB) recovery in CS has been shown to be highly variable despite immunosuppressive treatment, with no reliable tool available to predict odds of reversibility. This study sought to evaluate the potential of combined fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and resting myocardial perfusion imaging (rMPI) to predict reversibility of newly diagnosed high-grade AVB in cardiac sarcoidosis (CS).

METHODS

We performed a single-center, retrospective analysis of patients with CS presenting with high-grade AVB who underwent combined FDG-PET/CT and rMPI. The 2016 JCS and the 2014 HRS diagnostic criteria were used for the diagnosis of CS. Patients with a history of coronary artery disease or prior immunosuppressive treatment were excluded. Patients were divided into AVB recovery and non-recovery subgroups. CS disease staging was based on FDG-PET and rMPI findings: (Stage 0) normal FDG-PET and rMPI (Stage 1) positive FDG-PET and normal rMPI (Stage 2) positive FDG-PET with perfusion deficits on rMPI (Stage 3) normal FDG-PET with perfusion deficits on rMPI.

RESULTS

Twenty-seven patients, including 13 demonstrating AVB recovery, were identified. Eleven out of fourteen (78.6%) patients presenting with stage 1 CS demonstrated AVB recovery. Stage 1 CS was significantly more present in the recovery group compared to the non-recovery group (84.6% vs 21.4%, P = .002). Eleven presented with stage 2 CS, with only 2 (18.2%) recovering AV nodal conduction. Stage 2 CS presented more frequently in the non-recovery group (64.3% vs 15.4%, P = .020).

CONCLUSIONS

Combined FDG-PET and rMPI employed to stage CS disease presenting with high-degree AVB appears to have good performance for predicting likelihood of recovery.

Cardiac sarcoidosis: a comprehensive review of risk factors, pathogenesis, diagnosis, clinical manifestations, and treatment strategies

Cardiac Sarcoidosis (CS) is a deadly consequence of systemic sarcoidosis that inflames all three layers of the heart, especially the myocardium-clinical signs of CS range from asymptomatic disease to abrupt cardiac death. CS generally remains undiagnosed secondary to a lack of definitive diagnostic criteria, a high percentage of false negative results on endomyocardial biopsy, and ill-defining clinical manifestations of the disease. Consequently, there is a lack of evidence-based recommendations for CS, and the present diagnostic and therapeutic management depend on expert opinion. The aetiology, risk factors, clinical symptoms, diagnosis, and therapy of CS will be covered in this review. A particular emphasis will be placed on enhanced cardiovascular imaging and early identification of CS. We review the emerging evidence regarding the use of Electrocardiograms (ECGs), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) imaging of the heart to identify and quantify the extent of myocardial inflammation, as well as to guide the use of immunotherapy and other treatment regimens, such as ablation therapy, device therapy, and heart transplantation, to improve patient outcomes.

Clinical valuables related to resolution of complete or advanced atrioventricular block after steroid therapy in patients with cardiac sarcoidosis

BACKGROUND

Prediction of atrioventricular block (AVB) resolution after steroid therapy in patients with cardiac sarcoidosis (CS) is difficult.

METHODS

We identified 24 patients with CS and complete or advanced AVB receiving steroid therapy. AVB resolution was assessed by reviewing surface electrocardiogram and the percentage of ventricular pacing required on subsequent device interrogation reports.

RESULTS

AVB resolution was noted in eight (33%) patients 1 year after receiving steroid therapy. Univariate Cox regression analysis demonstrated that left ventricular ejection fraction (LVEF) (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.01-1.14, P = .016), interval from recognized AVB to start of steroid therapy (HR 0.98, 95% CI 0.95-0.99, P < .001), and lysozyme (HR 1.51, 95% CI 1.12-2.19, P = .013) were significantly associated with resolution of AVB. Combination of area under the curve (AUC) of each variable that was significantly related to resolution of AVB (AUC, 0.969; 95% CI 0.921-1.000, P < .001) was tended to be higher compared with each variable alone.

CONCLUSIONS

A shorter interval from recognition of AVB to start of steroid therapy, higher LVEF, and higher lysozyme levels were significantly associated with resolution of AVB after steroid therapy in patients with CS. The combination of each variable could be able to distinguish patients with resolution of AVB from those without.

Arrhythmias in Cardiac Sarcoidosis Bench to Bedside: A Case-Based Review

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and ¹⁸F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included.

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.

Sarcoidosis from Head to Toe: What the Radiologist Needs to Know

Sarcoidosis is a multisystem granulomatous disorder characterized by development of noncaseating granulomas in various organs. Although the etiology of this condition is unclear, environmental and genetic factors may be substantial in its pathogenesis. Clinical features are often nonspecific, and imaging is essential to diagnosis. Abnormalities may be seen on chest radiographs in more than 90% of patients with thoracic sarcoidosis. Symmetric hilar and mediastinal adenopathy and pulmonary micronodules in a perilymphatic distribution are characteristic features of sarcoidosis. Irreversible pulmonary fibrosis may be seen in 25% of patients with the disease. Although sarcoidosis commonly involves the lungs, it can affect virtually any organ in the body. Computed tomography (CT), magnetic resonance imaging, and positron emission tomography/CT are useful in the diagnosis of extrapulmonary sarcoidosis, but imaging features may overlap with those of other conditions. Familiarity with the spectrum of multimodality imaging findings of sarcoidosis can help to suggest the diagnosis and guide appropriate management. ^©RSNA, 2018.

Image fusion between 18F-FDG PET and MRI in cardiac sarcoidosis: A case series

BACKGROUND

Sarcoidosis is a systemic disorder of unknown etiology. It is distinguished by the presence of noncaseating epithelioid granulomas. This study demonstrates the use of image fusion between (18)F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) and magnetic resonance imaging (MRI) to diagnose patients with cardiac sarcoidosis (CS).

METHODS

Seven patients diagnosed with sarcoidosis were retrospectively included. All patients underwent 18F-FDG PET/CT and cardiac MRI.

RESULTS

On the MRI scan, late gadolinium enhancement (LGE) was observed in five patients. T2-weighted images revealed areas with an increased signal consistent with myocardial edema in two patients and with hypointensity suggesting fibrosis in one patient. Increased 18F-FDG uptake was seen in the myocardial wall in three patients, indicating active inflammation.

CONCLUSION

18F-FDG PET and MRI image fusion allows clinicians to obtain complete morphofunctional cartography in patients with sarcoidosis. Our data show that 18F-FDG PET/MRI image fusion imaging can be useful in the diagnosis of CS.

Update on Treatment in Cardiac Sarcoidosis

OPINION STATEMENT

The prevalence of cardiac sarcoidosis has exponentially increased over the past decade, primarily due to increased awareness and diagnostic modalities for the disease entity. Despite an expanding patient cohort, the optimal management of cardiac sarcoidosis remains yet to be established with a significant lack of prospective trials to support current practice. Corticosteroids remain first-line treatment of this disorder, and we recommend that immunosuppressive therapy should be initiated in all patients diagnosed with cardiac sarcoidosis. Additional pharmacotherapy may be necessary based on disease manifestations and response to treatment. The use of nuclear imaging with ¹⁸fluorodeoxyglucose (¹⁸FDG) positron emission tomography (PET) to guide treatment has become more common, but lacks rigorous data from larger cohorts. Whether an improvement in inflammatory burden as assessed by ¹⁸FDG-PET is correlated with clinical outcomes is as yet unproven. Device therapy with implantable-cardioverter defibrillators should be considered in all cardiac sarcoidosis patients for either primary or secondary prevention of ventricular arrhythmias and cardiac death.

Disease-specific cardiovascular positron emission tomography/magnetic resonance imaging: a brief review of the current literature

The hybrid positron emission tomography/magnetic resonance (PET/MR) is a new imaging tool that has garnered immense research interest for its potentials to assist clinical investigations. PET/MR combines the quantitative measurement of PET with dynamic functional and anatomic assessment of MR and can deliver a robust clinical examination. Currently, simultaneous cardiovascular PET/MR imaging remains in the pre-clinical research stage, and most institutions have not adopted a clinical PET/MR clinical imaging service. Nevertheless, PET/MR examination has unique promises in several areas of cardiovascular medicine, and in recent years more and more research publications have become available to lend us insight into its utility in cardiovascular imaging. Here we review the existing literature on simultaneous cardiovascular PET/MR imaging, with an emphasis on organizing the current literature into disease-specific discussions. These areas include coronary artery disease (CAD), carotid atherosclerosis, various infiltrative, inflammatory and hereditary heart diseases, myocarditis, vasculitis, and cardiac mass assessment. The purpose of this review is to provide an overview of the current understanding of cardiovascular PET/MR clinical imaging, in a disease-specific manner, from a clinician's perspective. Potential limitations of simultaneous PET/MR, such as cost effectiveness, artifacts, contraindications, and radiation exposure, are briefly discussed.

Cardiac applications of PET

Routine use of cardiac positron emission tomography (PET) applications has been increasing but has not replaced cardiac single-photon emission computerized tomography (SPECT) studies yet. The majority of cardiac PET tracers, with the exception of fluorine-18 fluorodeoxyglucose (18F-FDG), are not widely available, as they require either an onsite cyclotron or a costly generator for their production. 18F-FDG PET imaging has high sensitivity for the detection of hibernating/viable myocardium and has replaced Tl-201 SPECT imaging in centers equipped with a PET/CT camera. PET myocardial perfusion imaging with various tracers such as Rb-82, N-13 ammonia, and O-15 H2O has higher sensitivity and specificity than myocardial perfusion SPECT for the detection of coronary artery disease (CAD). In particular, quantitative PET measurements of myocardial perfusion help identify subclinical coronary stenosis, better define the extent and severity of CAD, and detect ischemia when there is balanced reduction in myocardial perfusion due to three-vessel or main stem CAD. Fusion images of PET perfusion and CT coronary artery calcium scoring or CT coronary angiography provide additional complementary information and improve the detection of CAD. PET studies with novel 18F-labeled perfusion tracers such as 18F-flurpiridaz and 18F-FBnTP have yielded high sensitivity and specificity in the diagnosis of CAD. These tracers are still being tested in humans, and, if approved for clinical use, they will be commercially and widely available. In addition to viability studies, 18F-FDG PET can also be utilized to detect inflammation/infection in various conditions such as endocarditis, sarcoidosis, and atherosclerosis. Some recent series have obtained encouraging results for the detection of endocarditis in patients with intracardiac devices and prosthetic valves. PET tracers for cardiac neuronal imaging, such as C-11 HED, help assess the severity of heart failure and post-transplant cardiac reinnervation, and understand the pathogenesis of arrhytmias. The other uncommon applications of cardiac PET include NaF imaging to identify calcium deposition in atherosclerotic plaques and β-amyloid imaging to diagnose cardiac amyloid involvement. 18F-FDG imaging with a novel PET/MR camera has been reported to be very sensitive and specific for the differentiation between malignant and nonmalignant cardiac masses. The other potential applications of PET/MR are cardiac infectious/inflammatory conditions such as endocarditis.

F-18-fluorodeoxyglucose positron emission tomography-guided sampling of mediastinal lymph nodes in the diagnosis of cardiac sarcoidosis

Histologic proof of granulomatous inflammation is prerequisite for the diagnosis of cardiac sarcoidosis (CS). Because of the limited sensitivity of endomyocardial biopsy (EMB), confirmation of sarcoidosis often has to be acquired from extracardiac biopsies. We set out to review our experience of F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG PET) in guiding extracardiac tissue biopsies in suspected CS. We included in this work 68 consecutive patients with proved CS who had undergone cardiac F-18-FDG PET with (n = 57) or without whole-body imaging as part of initial diagnostic evaluation. Their hospital charts, imaging studies, and diagnostic biopsies were reviewed in retrospect. Whole-body PET images showed extracardiac foci of abnormally high F-18-FDG uptake in 39 of 57 patients, of whom 38 had involvement of mediastinal lymph nodes (MLN). Parallel F-18-FDG uptake was found in other lymph nodes (n = 10), lungs (n = 9), liver (n = 3), spleen (n = 2), and thyroid gland (n = 1). Adding the mediastinal findings at cardiac PET without whole-body imaging, abnormal F-18-FDG uptake in MLN was found in totally 43 of the 68 patients with CS (63%). Histology of systemic sarcoidosis was known at presentation of cardiac symptoms in 8 patients. Of the 60 patients with missing histology, 24 patients underwent mediastinoscopy for sampling of PET-positive MLN, most often (n = 20) after nondiagnostic EMB; microscopy revealed diagnostic noncaseating granulomatous inflammation in 24 of the 24 cases (sensitivity 100%). In the remaining 36 patients, sarcoidosis histology was confirmed by EMB (n = 30), by biopsy of lungs (n = 2) or peripheral lymph nodes (n = 2), or at autopsy (n = 1) or post-transplantation (n = 1). In conclusion, MLN accumulate F-18-FDG at PET in most patients with CS and provide a highly productive source for diagnostic biopsies either primarily or subsequent to nondiagnostic EMB.

Circulating CD14++CD16+ Monocyte Subsets as a Surrogate Marker of the Therapeutic Effect of Corticosteroid Therapy in Patients With Cardiac Sarcoidosis

BACKGROUND

We aimed to evaluate whether specific monocyte subsets could serve as surrogate markers of disease activity in cardiac sarcoidosis (CS) evaluated by 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET).

METHODS AND RESULTS

We studied 28 patients with CS (8 men; mean age: 61±9 years) diagnosed according to consensus criteria. We divided the patients into 2 groups: known CS receiving corticosteroid therapy (Rx(+); n=13) and new-onset CS (Rx(-); n=15), and analyzed 3 distinct monocyte subsets (CD14+CD16-, CD14++CD16+, and CD14+ -CD16+). Monocyte subsets were also analyzed in 10 Rx(-) patients before and 12 weeks after starting corticosteroid therapy. Inflammatory activity was quantified by 18F-FDG PET using the coefficient of variation (COV) of the standardized uptake value (SUV). The proportion of CD14++CD16+ monocytes in Rx(+) patients (10.8 [0.2-23.5] %) was significantly lower than in Rx(-) patients (23.0 [11.5-38.4] %, P=0.001). After corticosteroid therapy, the COV of the SUV was significantly improved from 0.32 [0.14-0.62] to 0.17 [0.04-0.43] (P=0.017). The proportion of CD14++16+ monocytes showed a significant decrease from 22.2 [8.8-38.4] % to 8.4 [1.8-16.8] % (P=0.001). The decrease in the proportion of CD14++16+ monocytes significantly correlated with the decrease in the COV of the SUV (r=0.495, P=0.027).

CONCLUSIONS

CD14++16+ monocytes are a possible surrogate marker of the therapeutic effect of corticosteroid therapy in CS.

Cardiac sarcoidosis: clinical manifestations, imaging characteristics, and therapeutic approach

Sarcoidosis is a multi-system disease pathologically characterized by the accumulation of T-lymphocytes and mononuclear phagocytes into the sine qua non pathologic structure of the noncaseating granuloma. Cardiac involvement remains a key source of morbidity and mortality in sarcoidosis. Definitive diagnosis of cardiac sarcoidosis, particularly early enough in the disease course to provide maximal therapeutic impact, has proven a particularly difficult challenge. However, major advancements in imaging techniques have been made in the last decade. Advancements in imaging modalities including echocardiography, nuclear spectroscopy, positron emission tomography, and magnetic resonance imaging all have improved our ability to diagnose cardiac sarcoidosis, and in many cases to provide a more accurate prognosis and thus targeted therapy. Likewise, therapy for cardiac sarcoidosis is beginning to advance past a “steroids-only” approach, as novel immunosuppressant agents provide effective steroid-sparing options. The following focused review will provide a brief discussion of the epidemiology and clinical presentation of cardiac sarcoidosis followed by a discussion of up-to-date imaging modalities employed in its assessment and therapeutic approaches.

Quantitative interpretation of FDG PET/CT with myocardial perfusion imaging increases diagnostic information in the evaluation of cardiac sarcoidosis

BACKGROUND

FDG PET/CT with myocardial perfusion imaging is a useful method for evaluating cardiac sarcoidosis (CS), but interpretation is not standardized. We developed a method for quantification of cardiac FDG PET/CT and evaluated its relationship to conventional interpretation, perfusion defects, clinical events, and immunosuppressive treatment.

METHODS AND RESULTS

FDG PET/CT with MPI studies performed for CS (n = 38) were retrospectively compared to negative control studies acquired for oncologic indications (n = 10). Quantitative measures of FDG volume-intensity (Cardiac Metabolic Activity, CMA) was performed using standardized uptake values (SUVs). CMA (477.7 ± 909 vs 0.55 ± 2.1 vs 0.3 ± 0.3 g glucose, P = .02) was significantly greater in visually FDG-positive studies compared to visually negative and oncologic negative studies. Among patients with CS, CMA was greater in studies with an EF < 50% (760.3 ± 1,148 vs 87.4 ± 161 g glucose, P = .03) and preceding an adverse clinical event (1,095 ± 1,253 vs 73 ± 144 g glucose, P = .006). CMA was the only independent predictor of events by multivariate analysis. In patients with repeat examinations (n = 7), CMA decreased with prednisone treatment in 5 of 6 patients.

CONCLUSIONS

Quantification of FDG uptake in CS correlates with lower EFs, clinical events, and immunosuppression treatment.

Assessment of cardiac sarcoidosis with advanced imaging modalities

Sarcoidosis is a chronic systemic disease of unknown etiology that is characterized by the presence of noncaseating epithelioid granulomas, usually in multiple organs. Several studies have shown that sarcoidosis might be the result of an exaggerated granulomatous reaction after exposure to unidentified antigens in genetically susceptible individuals. Cardiac involvement may occur and lead to an adverse outcome: the heart mechanics will be affected and that causes ventricular failure, and the cardiac electrical system will be disrupted and lead to third degree atrioventricular block, malignant ventricular tachycardia, and sudden cardiac death. Thus, early diagnosis and treatment of this potentially devastating disease is critically important. However, sensitive and accurate imaging modalities have not been established. Recent studies have demonstrated the promising potential of cardiac magnetic resonance imaging (MRI) and (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) in the diagnosis and assessment of cardiac sarcoidosis (CS). In this review, we discuss the epidemiology, etiology, histological findings, and clinical features of sarcoidosis. We also introduce advanced imaging including (18)F-FDG PET and cardiac MRI as more reliable diagnostic modalities for CS.

Deterioration of cardiac function during the progression of cardiac sarcoidosis: diagnosis and treatment

The cardiac involvement of sarcoidosis causes progressive heart failure symptoms and is a life-threatening condition; thus, an early and appropriate diagnosis of this condition is crucial. On the other hand, the decline in the cardiac function is rapid; therefore, patients usually have moderate-severe left ventricular dysfunction when diagnosed with cardiac sarcoidosis, which may decrease the effectiveness of therapies. We herein report three illustrative cases of heart failure due to cardiac sarcoidosis in patients who were or were not diagnosed with preceding systemic sarcoidosis. We also discuss the currently available diagnostic modalities and possible biomarkers for the diagnosis of cardiac sarcoidosis.

Clinical value of a high-fat and low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis

BACKGROUND

We hypothesized that a high-fat and low-carbohydrate (HFLC) diet before FDG-PET/CT could identify patients with active cardiac sarcoidosis (CS).

METHODS

Fifty-eight sarcoidosis patients with a suspicion of CS consumed a HFLC diet before FDG-PET/CT. Clinical, electrical, and other imaging investigations were compared to PET results.

RESULTS

Using Japanese Ministry of Health and Welfare (JMHW) criteria as a gold standard, 21% (12/58) of patients had a CS. Sensitivity and specificity of PET (visual analysis) were 83% (10/12) and 78% (36/46), respectively, with a very good interobserver agreement (k = 0.86). 70% (7/10) of the patients with a positive PET and negative JMHW criteria exhibited abnormalities suggestive of CS either on MR (n = 3) or SPECT (n = 4). Comparison with the presence of delayed enhancement on magnetic resonance imaging helped to classify patients with active (PET positive) or non-active CS (PET negative). In addition, when MR and PET were both negative, none of the patients met the JMHW criteria. PET response under treatment was concordant with clinical evolution in 11/13 patients.

CONCLUSIONS

FDG-PET/CT after HFLC diet is a sensitive tool for the diagnosis of active CS. Combined use of PET and MR is promising for the detection and characterization of CS lesions.

Arrhythmias in cardiac sarcoidosis: diagnosis and treatment

PURPOSE OF REVIEW

Sarcoidosis is a granulomatous disease of unclear cause and variable presentation. Cardiac involvement can result in life-threatening conditions including heart block, ventricular tachycardia, sudden cardiac death, and heart failure. There is no consensus on the diagnosis and management of cardiac sarcoidosis and a practical update is needed to provide clinicians with guidance.

RECENT FINDINGS

Three recent studies have described cardiac manifestations as the first presentation of sarcoidosis. In one study, cardiac sarcoidosis was found to be the underlying cause in 19% of adults aged less than 55 years presenting with new onset unexplained atrioventricular block. Also, there are increasing reports of patients with isolated cardiac sarcoidosis (i.e., without sarcoid in other organs). Finally, advances in imaging have enhanced our ability to detect myocardial involvement and perhaps follow response to treatment.

SUMMARY

Cardiac sarcoidosis should be considered in patients aged less than 55 years presenting with unexplained atrioventricular block and in patients with idiopathic cardiomyopathy and sustained ventricular tachycardia. Much remains to be learned about the condition, including the role of steroids and devices in treatment, and the place of advanced imaging in following the response to treatment. Collaborative multicenter studies are required to answer these important clinical questions.

¹⁸F-Fluoro-2-deoxyglucose positron emission tomography in cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a rare and potentially life-threatening disease that causes conduction disturbance, systolic dysfunction, and most notably sudden cardiac death. Accurate diagnosis of CS is thus mandatory; however, a reliable approach that enables diagnosis of CS with high sensitivity and specificity has yet to be established. Recent studies have demonstrated the promising potential of (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) in the diagnosis and assessment of CS. Indeed, (18)F-FDG PET provides a wide variety of advantages over previous imaging modalities; however, there are pitfalls and limitations that should be recognized. In this review article, (1) the rationale for (18)F-FDG PET application in CS, (2) suitable pretest preparations, and (3) evaluation protocols for the (18)F-FDG PET images obtained will be addressed. In particular, sufficient suppression of physiological (18)F-FDG uptake in the heart is essential for accurate assessment of CS. Also, (4) recent studies addressing the diagnostic role of (18)F-FDG PET and (5) the clinically important differences between (18)F-FDG PET and other imaging technologies will be reviewed. For example, active sarcoid lesions and their response to steroid treatment will be better detected by (18)F-FDG PET, whereas fibrotic lesions might be shown more clearly by magnetic resonance imaging or other nuclear myocardial perfusion imaging. In the last decade, (18)F-FDG PET has substantially enhanced detection of CS; however, CS would be better evaluated by a combination of multiple modalities. In the future, advances in (18)F-FDG PET and other emerging imaging modalities are expected to enable better management of patients with sarcoidosis.

Early detection of cardiac sarcoid lesions with (18)F-fluoro-2-deoxyglucose positron emission tomography

In April 2005, a 72-year-old woman with pulmonary sarcoidosis exhibited focal (18)F-fluoro-2-deoxyglucose ((18)F-FDG) uptake in her heart on (18)F-FDG positron emission tomography (PET). Although Japanese guidelines for diagnosing cardiac sarcoidosis were not met at this point, electrocardiography, echocardiography, and magnetic resonance imaging became diagnostic for cardiac sarcoidosis 1 year later. In the present case report, the potential of (18)F-FDG PET in the early recognition of cardiac sarcoidosis in comparison with other imaging modalities is discussed.

Cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a rare but potentially fatal condition that may present with a wide range of clinical manifestations including congestive heart failure, conduction abnormalities, and most notably, sudden death. Recent advances in imaging technology allow easier detection of CS, but the diagnostic guidelines with inclusion of these techniques have yet to be written. It has become clear that minimally symptomatic or asymptomatic cardiac involvement is far more prevalent than previously thought. Because of the potential life-threatening complications and potential benefit of treatment, all patients diagnosed with sarcoidosis should be screened for cardiac involvement. Patients with CS and symptoms such as syncope need an aggressive workup for a potentially life-threatening etiology, and often require implantable cardioverter-defibrillator therapy. CS patients without arrhythmic symptoms are still at risk for sudden death and may warrant an implantable cardioverter-defibrillator for primary prevention reasons. Although corticosteroids are regarded as the first-line drug of choice, therapy for CS is not yet standardized, and it is unclear at this point whether asymptomatic patients require therapy. Randomized clinical trials are clearly warranted to answer these very important patient care questions, and are endorsed fully by the authors.

Myocardial imaging with 18F-fluoro-2-deoxyglucose positron emission tomography and magnetic resonance imaging in sarcoidosis

PURPOSE

Despite accumulating reports on the clinical value of (18)F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) and magnetic resonance imaging (MRI) in the assessment of cardiac sarcoidosis, no studies have systematically compared the images of these modalities.

METHODS

Twenty-one consecutive patients with suspected cardiac sarcoidosis underwent cardiac examinations that included 18F-FDG PET and MRI. The association of 18F-FDG PET and MRI findings with blood sampling data such as serum angiotensin converting enzyme levels was also evaluated.

RESULTS

Eight of 21 patients were diagnosed as having cardiac sarcoidosis according to the Japanese Ministry of Health and Welfare Guidelines for Diagnosing Cardiac Sarcoidosis. Sensitivity and specificity for diagnosing cardiac sarcoidosis were 87.5 and 38.5%, respectively, for 18F-FDG PET, and 75 and 76.9%, respectively, for MRI. When the 18F-FDG PET and MRI images were compared, 16 of 21 patients showed positive findings in one (n = 8) or both (n = 8) of the two modalities. In eight patients with positive findings on both images, the distribution of the findings differed among all eight cases. The presence of positive findings on 18F-FDG PET was associated with elevated serum angiotensin-converting enzyme levels; this association was not demonstrated on MRI.

CONCLUSIONS

Both 18F-FDG PET and MRI provided high sensitivity for diagnosing cardiac sarcoidosis in patients with suspected cardiac involvement, but the specificity of (18)F-FDG PET was not as high as previously reported. The different distributions of the findings in the two modalities suggest the potential of 18F-FDG PET and MRI in detecting different pathological processes in the heart.

Relationship between arrhythmogenesis and disease activity in cardiac sarcoidosis

BACKGROUND

In patients with cardiac sarcoidosis, ventricular arrhythmias and/or conduction disturbances are frequently observed and sometimes fatal. However, few reports on disease activity and arrhythmic events in cardiac sarcoidosis are available.

OBJECTIVE

The purpose of this study was to investigate the relationship between disease activity and arrhythmic events in cardiac sarcoidosis and the effect of corticosteroid therapy.

METHODS

The study population consisted of 15 cardiac sarcoidosis patients with new-onset symptomatic arrhythmia, including eight patients admitted once for complete atrioventricular block (CAVB), five patients admitted once for sustained ventricular tachycardia (VT), and two patients admitted twice for two arrhythmic events (one for CAVB and the other for sustained VT). Disease activity was evaluated by gallium-67 citrate (Ga) scintigraphy. All patients with positive Ga uptake were treated with corticosteroids, and arrhythmic events were evaluated by repeat Holter recordings.

RESULTS

Positive uptake of Ga was observed in 8 (80%) of the 10 CAVB events and in 1 (14%) of the 7 sustained VT events (80% vs 14%, P = .02). Corticosteroids abolished myocardial Ga uptake in all nine patients with positive Ga uptake. After corticosteroid therapy was started, AV conduction improved in 5 of 9 CAVB patients (including 8 patients with new-onset CAVB and one patient with history of CAVB). However, ventricular arrhythmias were not improved after corticosteroid therapy.

CONCLUSION

In cardiac sarcoidosis patients, CAVB develops mainly during the active phase of the disease. Early treatment with corticosteroids might improve AV conduction disturbance. However, sustained VT is not closely linked with disease activity and frequently develops in the advanced stage of disease.

Evaluation of the relationship between physiological FDG uptake in the heart and age, blood glucose level, fasting period, and hospitalization

OBJECTIVE

Positron emission tomography (PET) with fluorodeoxyglucose (FDG) is widely used for evaluation of cancer and ischemic heart disease. Recently, increased myocardial FDG uptake has been reported to be related to some types of heart disease, such as sarcoidosis. However, the physiological increased FDG uptake in the heart often mimics the abnormal high uptake in these cases. In this study, we investigated the relationships between myocardial uptake and age, blood glucose level, fasting period, and hospitalization status (inpatient vs. outpatient).

METHODS

A total of 159 non-diabetic patients were enrolled in the present study. Patients were imaged on a PET/CT scanner, and a three-dimensional region of interest (ROI) was drawn on the fused PET/CT image to measure the maximum standardized uptake value (SUV(max)) of the whole left ventricle.

RESULTS

No significant relationships were observed between myocardial uptake and age or fasting period. Blood glucose level showed a significant relationship (p = 0.025) with myocardial uptake, but the R-square was extremely small (r2 = 0.03). With an SUV(max) threshold of 3.0, there was no significant difference between inpatients and outpatients. However, outpatients showed a significantly higher frequency of myocardial uptake over SUV(max) of 5.0 (chi2 test: p = 0.046).

CONCLUSION

It is difficult to predict the degree of physiological uptake in the heart from data regarding age, fasting period, or blood glucose level. Outpatients tend to show higher myocardial uptake than inpatients, which may make it difficult to detect abnormally increased uptake in the heart. A long fasting period, such as overnight fasting, is an inadequate means to reduce the physiological uptake of FDG in the heart.

18F-Fluorodeoxyglucose Positron Emission Tomography in a Case of Retroperitoneal Fibrosis

A patient with recurrent abdominal pain was admitted to our hospital. Computed tomography showed a soft dense mass surrounding the abdominal aorta at the infrarenal level, which was compatible with retroperitoneal fibrosis. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography showed abnormal uptake of (18)F-FDG into these lesions. Two months after the initiation of corticosteroid therapy, the abnormal uptake of (18)F-FDG had ceased along with a reduction in the fibrous mass surrounding the abdominal aorta.

Usefulness of Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography in a Patient With Takayasu's Arteritis Associated With Antiphospholipid Syndrome

A 36-year-old woman was admitted for recurring chest pain and hemoptysis. Blood pressure in the right and left arms was equal, and no murmurs or bruits were heard. Body temperature was normal on admission and remained within the normal range during the hospital stay. C-reactive protein was slightly elevated (2.3 mg/dL) and lupus anticoagulant was positive. Angiography showed no abnormality of the aorta or its branches, but the left pulmonary artery showed occlusion at the proximal portion. Computed tomography (CT) revealed segmental wall thickening of the thoracic aorta. Fluorine-18-fluorodeoxyglucose positron emission tomography (18FDG PET) showed high uptake in the proximal portion of the left pulmonary artery and in the thoracic aorta with wall thickening on CT. Based on these findings, a diagnosis of Takayasu's arteritis associated with antiphospholipid syndrome was made and high-dose steroid therapy (prednisolone 30 mg/day) was started. Two months later, the C-reactive protein level had decreased from 2.3 mg/dL to 1.1 mg/dL, and both the focal wall thickening and (18)FDG uptake of the thoracic aorta were decreased. 18FDG PET was useful for evaluating the efficacy of the steroid therapy in addition to making a diagnosis of Takayasu's arteritis associated with antiphospholipid syndrome.

Detection of cardiac sarcoidosis using cardiac markers and myocardial integrated backscatter

BACKGROUND

It is not known whether cardiac markers and cyclic variations of integrated backscatter can be used to detect cardiac sarcoidosis.

METHODS

We studied 62 patients with sarcoidosis affecting the lung, eyes, skin, or heart (27 patients with cardiac involvement and 35 patients without). The cyclic variation of integrated backscatter and wall thickening was evaluated in the left ventricular anterior septum and posterior wall. Plasma A-type natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) concentrations and serum cardiac troponin T were also determined.

RESULTS

Plasma natriuretic peptide concentrations were higher in the cardiac involvement group (ANP: 15.5 [interquartile range (IQR) 2.5-34.0] vs. 12.0 [10.0-16.5] pg/ml, P=0.25; BNP: 28.6 [5.9-141] vs. 10.1 [4.8-15.4] pg/ml, P=0.049). However, cardiac troponin T concentration was <0.01 ng/ml in all patients. Receiver-operator characteristic (ROC) analysis showed that both ANP and BNP could identify patients with high-degree atrioventricular block, ventricular tachyarrhythmias, or symptomatic heart failure (the areas under the ROC curve were 0.94 and 0.97, respectively). The cardiac involvement group could be distinguished from the noninvolvement group by combining cutoff values for the magnitude of integrated backscatter cyclic variation (5.5 dB) and wall thickening (30%), albeit only for the posterior wall.

CONCLUSION

Both ANP and BNP are useful markers for identifying patients with sarcoidosis and cardiac complication(s). Moreover, evaluation of integrated backscatter cyclic variation combined with wall thickening may be of help in detecting cardiac involvement in the posterior wall.

Can revascularization restore sinus rhythm in patients with acute onset atrioventricular block?

BACKGROUND

We studied patients with coronary artery disease (CAD) and complete atrioventricular (AV) block of acute onset that were treated with coronary artery bypass grafting (CABG) to see whether revascularization can restore the sinus rhythm.

METHODS

CABG was performed on eight patients with newly developed complete AV block and severe CAD. The distribution of coronary artery lesions showed a type IV pattern in six patients and a type II pattern in two patients. Complete revascularization was performed in six patients. Left anterior descending artery was revascularized in all eight patients. The patients were followed-up after operation for approximately 10 days before the implantation of a permanent pacemaker to see if they recover from AV block.

RESULTS

The mean interval from development of complete AV block to operation was 3.63 +/- 1.3 days. There was no operative and/or early mortality. None of the patients recovered from complete AV block after coronary revascularization. Early morbidity was not detected. The mean hospital stay (12.75 +/- 1.49 days) and intensive care unit stay (30.25 +/- 19.39 hours) were relatively long because of the delay in permanent pacemaker implantation. All patients were asymptomatic at the end of their follow-up period (23.38 +/- 18.41 months).

CONCLUSIONS

Preoperatively developed complete AV block did not adversely affect the operative and early postoperative outcome of CABG operations. Recovery from complete AV block cannot be achieved by coronary revascularization performed 3.63 +/- 1.3 days after the onset of complete AV block.

Early detection of cardiac involvement in patients with sarcoidosis by a non-invasive method with ultrasonic tissue characterisation

OBJECTIVES

To clarify the value of cycle dependent variation of myocardial integrated backscatter (CV-IB) analysis, which non-invasively measures acoustic properties of the myocardium, for early detection of cardiac involvement in patients with sarcoidosis.

METHODS

The study population consisted of 22 consecutive patients with biopsy proven sarcoidosis who did not have any abnormal findings on conventional two dimensional echocardiogram. Cardiac sarcoidosis was diagnosed by radionuclide testing including thallium-201 scintigraphy, gallium-67 scintigraphy, and cardiac fluorine-18-deoxyglucose positron emission tomography. The magnitude and delay of the CV-IB were analysed in the basal mid septum and the basal mid posterior wall of the left ventricle of all patients.

RESULTS

The patients were divided into two groups: 8 patients with cardiac involvement and 14 patients without cardiac involvement. In the basal septum, a major reduction in the magnitude (mean (SD) 1.8 (4.4) v 6.6 (1.3), p = 0.012) and an increase in the time delay (1.3 (0.5) v 1.0 (0.1), p = 0.038) of CV-IB were observed in patients with cardiac sarcoidosis even in the absence of two dimensional echocardiographic abnormalities. The sensitivity for detecting cardiac involvement was such that the magnitude of CV-IB in the basal septum discriminated 75% of patients with cardiac sarcoidosis from those with non-cardiac sarcoidosis, whereas two dimensional echocardiographic parameters did not discriminate between these two groups.

CONCLUSIONS

The CV-IB is decreased in the basal septum in patients with cardiac sarcoidosis even in the absence of two dimensional echocardiographic abnormalities. Analysis of CV-IB may be a useful method to detect early myocardial involvement in patients with sarcoidosis.

Sarcoid heart disease: clinical course and treatment

Sarcoidosis is a rare granulomatous disease of unknown etiology that can affect any organ. Cardiac involvement, although uncommon, has a wide spectrum of clinical manifestations and is potentially fatal. Although there is no agreement upon a strategy for the diagnosis (which is difficult to make based on clinical information alone), the introduction of newer technology is promising and may be useful both for the early diagnosis of cardiac involvement and for the evaluation of response to therapy. Early treatment is crucial in improving symptoms and prognosis. ICD implantation and cardiac transplantation may offer improvements in management, as steroid therapy and pacemaker implantation has led to improved outcomes over the past three decades.

Diagnosis de localisations cardiaques et suivi longitudinal de 24 sarcoïdoses

PURPOSE

Cardiac sarcoidosis is responsible for 50% of deaths which mainly occur by ventricular arrhythmia or conduction disorders. The aim of this study is to determine the value of cardiac explorations for an early diagnosis of these localizations, which are often underestimated and can cause sudden death.

PATIENTS AND METHODS

We prospectively studied 24 consecutive patients, aged 33 +/-10 years, presenting with a sarcoidosis. Nine (38%) were asymptomatic and had no treatment. Fifteen (62%) were symptomatic: two (8%) had only pulmonary lesions and 13 (54%) had a polyvisceral disease. Seven (30%) were treated. Thirteen (54%) had an elevation of the disease activity markers. The patients had a 12-lead ECG, an echocardiography (TTE), a Holter ECG and a Magnetic Resonance Imaging (MRI) at inclusion.

RESULTS

Realization rate was: 100% ECG (24), 83% TTE (20), 75% Holter ECG (18) and 62% MRI (15). Only two patients (8%) had a cardiac involvement. The first one had a polyvisceral sarcoidosis presenting with a hypokinetic cardiomyopathy and a complete AV block and the second one presented with a complete AV block which revealed sarcoidosis. Both patients had a MRI septal hypersignal and disease activity markers. They were treated with cardiac stimulation and corticotherapy: the first patient died suddenly, the second one remains asymptomatic after a 14 months follow-up. The 22 patients (92%) with normal explorations did not present any cardiac involvement during the follow-up (3.7 +/-1.6 years).

CONCLUSIONS

This study confirms the rarity of cardiac involvement in sarcoidosis. An exhaustive cardiac check-up does not seem very productive even for patients presenting with polyvisceral disease or an elevation of disease markers. A systematic 12-lead ECG seems to be the most useful and simple tool for the early diagnosis of cardiac sarcoidosis. The other explorations will be realized according to clinical data. The absence of abnormal findings seems to have a good negative predictive value allowing to rule out a cardiac problem.