RESUMEN
BACKGROUND: 18F-Fluoride positron emission tomography (PET) and computed tomography (CT) can measure disease activity and progression in aortic stenosis. Our objectives were to optimize the methodology, analysis, and scan-rescan reproducibility of aortic valve 18F-fluoride PET-CT imaging. METHODS AND RESULTS: Fifteen patients with aortic stenosis underwent repeated 18F-fluoride PET-CT. We compared nongated PET and noncontrast CT, with a modified approach that incorporated contrast CT and ECG-gated PET. We explored a range of image analysis techniques, including estimation of blood-pool activity at differing vascular sites and a most diseased segment approach. Contrast-enhanced ECG-gated PET-CT permitted localization of 18F-fluoride uptake to individual valve leaflets. Uptake was most commonly observed at sites of maximal mechanical stress: the leaflet tips and the commissures. Scan-rescan reproducibility was markedly improved using enhanced analysis techniques leading to a reduction in percentage error from ±63% to ±10% (tissue to background ratio MDS mean of 1.55, bias -0.05, limits of agreement -0·20 to +0·11). CONCLUSIONS: Optimized 18F-fluoride PET-CT allows reproducible localization of calcification activity to different regions of the aortic valve leaflet and commonly to areas of increased mechanical stress. This technique holds major promise in improving our understanding of the pathophysiology of aortic stenosis and as a biomarker end point in clinical trials of novel therapies. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02132026.
Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/patología , Calcinosis/diagnóstico por imagen , Fluorodesoxiglucosa F18/administración & dosificación , Tomografía Computarizada por Tomografía de Emisión de Positrones , Radiofármacos/administración & dosificación , Anciano , Anciano de 80 o más Años , Válvula Aórtica/fisiopatología , Estenosis de la Válvula Aórtica/fisiopatología , Calcinosis/fisiopatología , Técnicas de Imagen Sincronizada Cardíacas , Medios de Contraste/administración & dosificación , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Estudios Prospectivos , Reproducibilidad de los Resultados , Escocia , Índice de Severidad de la EnfermedadRESUMEN
We present a case of cardiac sarcoidosis of insidious onset mimicking arrhythmogenic right ventricular cardiomyopathy. Our patient initially presented with systemic sarcoidosis but later developed palpitations. The similarity in clinical presentation and cardiac magnetic resonance findings in both conditions posed a challenge in differentiating between the two in the absence of histological diagnosis. We highlighted the role of positron emission tomography in aiding a diagnosis.