Right Atrial Fluorodeoxyglucose Uptake Is a Risk Factor for Stroke and Improves Prediction of Stroke Above the CHA2DS2-VASc Score in Patients With Atrial Fibrillation

Atrial FDG uptake and atrial fibrillation: A systematic review and meta-analysis

Background

Atrial inflammatory and metabolic derangements have been reported in patients with atrial fibrillation (AF).

Objective

We sought to evaluate the association of 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) in the left and right atria and AF.

Methods

We conducted a systematic review and meta-analysis, using the PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, of studies involving patients undergoing FDG-PET scans with reported atrial or ventricular uptake and outcomes of AF. Data were pooled and analyzed, and FDG uptake in AF and non-AF patients was compared using odds ratios (ORs).

Results

Six studies (4 retrospective, 1 prospective, and 1 case-control) were included in the meta-analysis of studies on patients not meeting diagnostic criteria for cardiac sarcoidosis (CS): 832 patients with a mean age of 67 years, 62% male, and 53% with hypertension. AF patients demonstrated higher odds of FDG uptake in the left atrium (pooled OR 14.50, 95% confidence interval 6.78-31.02; P < .0001, I 2 = 0) and right atrium (pooled OR 51.98, 95% confidence interval 22.77-118.63, P < .0001, I 2 = 0). Two studies on patients met diagnostic criteria for CS: one did not report atrial uptake and the other did not demonstrate a statistically significant association between right or left atrial uptake in AF patients.

Conclusion

In patients undergoing FDG-PET without meeting CS diagnostic criteria, FDG uptake in the atria was strongly associated with AF, suggesting altered metabolism or inflammation in AF pathophysiology and risk assessment.

Associations of subclinical microcalcification and inflammation with carotid atheroma development: a dual-tracer PET/CT study

PURPOSE

Carotid artery atherosclerosis, a significant manifestation of cardiovascular disease (CVD) and leading cause of stroke, develops through a gradual process of arterial inflammation and calcification. This study explores the relationship between arterial inflammation (18 F-FDG PET/CT) and vascular calcification (18 F-NaF PET/CT) in the left and right common carotid arteries (LCC/RCC) and their association with CVD and thromboembolic risk in patients with subclinical atherosclerosis.

METHODS

A cohort of 115 subjects (73 healthy volunteers, 42 at-risk for CVD) underwent 18 F-NaF and 18 F-FDG PET/CT imaging. Radiotracer uptake was quantitatively assessed by measuring the average blood-pool-corrected mean standardized uptake value (aSUVmean).

RESULTS

Relative to healthy volunteers, at-risk subjects had greater uptake of NaF and FDG (10-22% and 16-27% higher, respectively, in both arteries, p < 0.05). On multivariate regression, NaF aSUVmean correlated with age and BMI (p < 0.01), and FDG aSUVmean correlated with BMI (p ≤ 0.01), fibrinogen (p < 0.01 in LCC only), and total cholesterol (p = 0.02 in RCC only). NaF aSUVmean increased with elevated 10-year CVD risk (p = 0.003 in LCC only), while no significant trend was seen for FDG. NaF and FDG aSUVmean increased with elevated thromboembolic risk in both arteries (p < 0.05). No correlations between NaF and FDG aSUVmean were observed (p > 0.05).

CONCLUSION

18 F-NaF PET/CT may serve as a prognostic tool for carotid microcalcification and subclinical atherosclerosis, while the utility of 18 F-FDG PET/CT remains uncertain.

CLINICAL TRIAL REGISTRATION

"Cardiovascular Molecular Calcification Assessed by 18F-NaF PET CT (CAMONA)", NCT01724749, https://clinicaltrials.gov/study/NCT01724749 .

Atrial FDG Uptake: Etiologies, Clinical Significance, and Implications

PURPOSE OF REVIEW

This review aims to explore the clinical significance of atrial fluorodeoxyglucose (FDG) uptake observed in positron emission tomography (PET) scans, focusing on its association with atrial fibrillation (AF), cardiac sarcoidosis, and myocarditis. We discuss the implications of atrial uptake for patient management and prognosis.

RECENT FINDINGS

Recent studies have demonstrated that atrial FDG uptake is frequently present in patients with AF, particularly those with persistent AF, and is linked to increased risks of stroke and poorer outcomes after ablation. In cardiac sarcoidosis, atrial uptake correlates with inflammation and an elevated risk of AF. Additionally, non-granulomatous myocarditis has been associated with localized atrial FDG uptake, necessitating careful differentiation from other causes. : Atrial FDG uptake reflects underlying pathological processes such as inflammation, which can significantly impact patient management and outcomes across various cardiovascular diseases. Recognizing these findings can facilitate early intervention, improve prognosis, and support the development of clear guidelines for clinical practice, emphasizing the need for continued research in this area.

Assessment of Pulmonary Arteries Hemodynamics and Its Relationship With Cardiac Remodeling and Myocardial Fibrosis in Athletes With Four-Dimensional Flow MRI

BACKGROUND

Exercise-induced cardiac remodeling (CR) and myocardial fibrosis (MF) can increase cardiovascular risk in athletes. Early detection of pulmonary arterial hemodynamics parameters among athletes may be beneficial in optimizing the frequency of clinical follow-ups.

PURPOSE

To analyze the hemodynamics of pulmonary arteries and its relationship with CR and MF in athletes using four-dimensional (4D) flow MRI.

STUDY TYPE

Prospective.

POPULATION

One hundred twenty-one athletes (median age, 24 years; mean exercise per week 10 hours, for mean of 5 years) and twenty-one sedentary healthy controls (median age, 25 years; exercise per week <3 hours, irregular pattern).

FIELD STRENGTH/SEQUENCE

True fast imaging with steady state free precession, time-resolved 3D Cartesian phase-contrast, and phase sensitive inversion recovery late gadolinium enhancement sequences at 3.0 T.

ASSESSMENT

CR was defined as any cardiac parameters exceeding the 99th percentile upper reference limits, encompassing ventricular function, bi-atrium and bi-ventricle diameters, and ventricular wall thickness. MF was visually evaluated by three independent radiologists. 4D flow parameters were assessed in the main, right, and left pulmonary arteries (MPA, RPA, and LPA, respectively) and compared between different groups. Four machine learning (ML) models were developed to differentiate between athletes with and without CR and/or MF.

STATISTICAL TESTS

Univariate analysis was used to compare groups. Area under the receiver operating characteristic curve (AUC) was used to assess the performance of the ML models.

RESULTS

Athletes had significantly higher WSSmax in the MPA, RPA, and LPA than controls. Athletes with CR and/or MF (N = 30) had significantly lower RPmax from MPA to RPA than those without (N = 91). Among the ML models, the gradient boosting machine model had the highest performance, with an AUC of 0.90.

CONCLUSION

The pulmonary arterial hemodynamics parameters could differentiate CR and/or MF in athletes, which may be potential to assist in optimizing frequency of follow-up.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

The relationship between right atrial wall inflammation and poor prognosis of atrial fibrillation based on 18F-FDG positron emission tomography/computed tomography

Background

Atrial fibrillation (AF) has been identified to increase stroke risk, even after oral anticoagulants (OACs), and the recurrence rate is high after radiofrequency catheter ablation (RFCA). Inflammation is an essential factor in the occurrence and persistence of AF. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is an established molecular imaging modality to detect local inflammation. We aimed to investigate the relationship between atrial inflammatory activity and poor prognosis of AF based on 18F-FDG PET/CT.

Methods

A total of 204 AF patients including 75 with paroxysmal AF (ParAF) and 129 with persistent AF (PerAF) who underwent PET/CT before treatment were enrolled in this prospective cohort study. Clinical data, electrocardiograph (ECG), echocardiography, and cardiac 18F-FDG uptake were collected. Follow-up information was obtained from patient clinical case notes or telephone reviews, with the starting point being the time of PET/CT scan. The follow-up deadline was either the date of AF recurrence after RFCA, new-onset stroke, or May 2023. Cox proportional hazards regression models were used to identify predictors of poor prognosis and hazard ratios (HRs) with 95% confidence intervals (CIs) was calculated.

Results

Median follow-up time was 29 months [interquartile range (IQR), 22-36 months]. Poor prognosis occurred in 52 patients (25.5%), including 34 new-onset stroke patients and 18 recrudescence after RFCA. The poor prognosis group had higher congestive heart failure, hypertension, age ≥75 years (doubled), diabetes mellitus, prior stroke or transient ischemic attack (TIA) or thromboembolism (doubled), vascular disease, age 65-74 years, sex category (female) (CHA2DS2-VASc) score [3.0 (IQR, 1.0-3.75) vs. 2.0 (IQR, 1.0-3.0), P=0.01], right atrial (RA) wall maximum standardized uptake value (SUVmax) (4.13±1.82 vs. 3.74±1.58, P=0.04), higher percentage of PerAF [39 (75.0%) vs. 90 (59.2%), P=0.04], left atrial (LA) enlargement [45 (86.5%) vs. 104 (68.4%), P=0.01], and RA wall positive FDG uptake [40 (76.9%) vs. 79 (52.0%), P=0.002] compared with the non-poor prognosis group. Univariate and multivariate Cox proportional hazard regression analysis concluded that only CHA2DS2-VASc score (HR, 1.29; 95% CI: 1.06-1.57; P=0.01) and RA wall positive FDG uptake (HR, 2.68; 95% CI: 1.10-6.50; P=0.03) were significantly associated with poor prognosis.

Conclusions

RA wall FDG positive uptake based on PET/CT is tightly related to AF recurrence after RFCA or new-onset stroke after antiarrhythmic and anticoagulation treatment.

Right atrial wall inflammation detected by 18F-FDG PET/CT may be significantly associated with persistent atrial fibrillation: a prospective case-control study

AIM

Atrial fibrillation (AF) is a progressive disease from paroxysmal to persistent, and persistent AF (PerAF) had worse prognosis. AF has potential link with inflammation, but it is not clear whether PerAF or paroxysmal AF (ParAF) is more closely related to inflammation. On the basis of inhibiting myocardial physiological uptake, 18F-fluorodeoxyglucosepositron emission tomography/computed tomography (18F-FDG PET/CT) is an established imaging modality to detect cardiac inflammation. We aimed to decipher the association between AF and atrial inflammatory activity by 18F-FDG PET/CT.

METHODS

Thirty-five PerAF patients were compared to age and sex matched ParAF group with baseline 18F-FDG PET/CT scans prior to radiofrequency catheter ablation (RFCA) in the prospective case-control study. High-fat and low-carbohydrate diet and prolonged fast (HFLC+Fast) was applied to all AF patients before PET/CT. Then 22 AF patients with positive right atrial (RA) wall FDG uptake (HFLC+Fast) were randomly selected and underwent HFLC+Fast+heparin the next day. The CHA2DS2-VASc score was calculated to evaluate the risk of stroke. Clinical data, ECG, echocardiography, and atrial 18F-FDG uptake were compared.

RESULTS

PerAF patients had significantly higher probability of RA wall positive FDG uptake and higher SUVmax than ParAF group [91.4% VS. 28.6%, P < 0.001; SUVmax: 4.10(3.20-4.90) VS. 2.60(2.40-3.10), P < 0.001]. Multivariate logistic regression analyses demonstrated that RA wall SUVmax was the independent influencing factor of PerAF (OR = 1.80, 95%CI 1.02-3.18, P = 0.04). In 22 AF patients with RA wall positive FDG uptake (HFLC+Fast), the "HFLC+Fast+Heparin" method did not significantly change RA wall FDG uptake evaluated by either quantitative analysis or visual analysis. High CHA2DS2-VASc score group had higher RA wall 18F-FDG uptake [3.35 (2.70, 4.50) vs, 2.8 (2.4, 3.1) P = 0.01].

CONCLUSIONS

RA wall FDG positive uptake was present mainly in PerAF. A higher RA wall 18F-FDG uptake was an independent influencing factor of PerAF. RA wall FDG uptake based on 18F-FDG PET/CT may indicate pathological inflammation.

TRIAL REGISTRATION

http://www.chictr.org.cn , ChiCTR2000038288.

Stroke and molecular imaging: a focus on FDG-PET

Stroke is the leading cause of disability worldwide, the second most common cause of dementia and the third leading cause of death. Though the etiology of stroke has been explored extensively, there remains open questions in the scientific and clinical study of stroke. Traditional imaging techniques, such as magnetic resonance imaging and computed tomography, have been applied extensively and remain mainstays in clinical practice. Nevertheless, positron emission tomography has proven to be a powerful molecular imaging tool in exploring the scientific aspects of neurological disease, and stroke remains an area of great interest. This review article examines the role of positron emission tomography in the study of stroke including its contributions to elaborating related pathophysiology and delving into possible clinical applications.