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Objective:To explore the diagnostic value of 18F-deoxyglucose (FDG) PET/CT dual-time-point imaging (DTPI) in the diagnosis of aortic grafts infection (AGI). Methods:Forty-two patients with suspected AGI were prospectively recruited in this DTPI study from October 2014 to October 2021. There were 35(83%) males and 7 females, mean age (54±15) years old, range 22-79 years old. PET/CT image quality was scored as 5 grading scale. Semi-quantitative analysis of DTPI data was performed using maximum standardized uptake value (SUVmax) of suspected AGI lesions. The percentage of SUVmax change between initial and delayed images were recorded as retention index (RI). Management of Aortic Graft Infection Collaboration (MAGIC) criteria were used as the diagnostic reference criteria for AGI.Results:According to the MAGIC criteria, 27 patients (64%) were positive for AGI, and 15 patients (36%) were negative. The mean RI of AGI was higher than that of non-AGI ones[(26.7±18.9)% vs. (6.4 ±18.8)%, P<0.01]. The sensitivity, specificity, and accuracy of initial SUVmax ≥6 with the presence of AGI was 88.9%, 73.3%, and 83.3%, respectively. Delayed SUVmax ≥6 improved the sensitivity (96.3%) and accuracy (88.1%) for diagnosing AGI. DTPI with 15% increment as the optimal cut-off value of RI improved the specificity (93.3%) and accuracy (90.5%) for diagnosing AGI. Fifteen (56%, 15/27) AGI patients had improved image quality grading on the delayed images, leading to more accurately delineating the detailed extent of the infected aortic graft. Conclusion:18F-FDG PET/CT DTPI has better diagnostic performance for AGI than conventional Single-time-point PET/CT imaging by improving image quality as well as enhancing delineation of infected aortic graft extent.
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Resumen: La infección sobre injerto protésico a nivel de aorta ascendente se considera una rara complicación con una incidencia de 0,5%-6%, pero de alta mortalidad (88%), incluso con tratamiento quirúrgico. Los factores de riesgo vinculados a este tipo de infección son: diabetes mellitus, insuficiencia renal e insuficiencia cardíaca. El microorganismo más frecuentemente implicado es Staphylococcus aureus. La presentación clínica puede ser muy variada, desde cuadros oligosintomáticos hasta sepsis. En cuanto al diagnóstico, los métodos de imagen clásicos (ecocardiograma, angiotomografía aórtica) resultan de gran relevancia. En la última década, la tomografía por emisión de positrones ha adquirido un rol relevante en las situaciones que presentan dudas diagnósticas, como es el caso del paciente que analizaremos.
Summary: Infection in a prosthetic graft in the ascending aorta is considered an infrequent complication with an incidence of 0.5%-6% but with high mortality (88%), even with surgical treatment. Related risk factors are diabetes mellitus, kidney failure and heart failure. The most frequent microorganism is Staphylococcus aureus. Clinical presentation can be very variable, from oligosymptomatic to sepsis. The classical imaging methods (ultrasonography, aortic angiotomography) are very relevant for diagnosis. In the last decade, positron emission tomography has acquired a relevant role in cases with diagnostic doubts, such as the patient to be analyzed.
Resumo: A infecção em prótese ao nível da aorta ascendente é considerada uma complicação rara, com incidência de 0,5%-6% mas com alta mortalidade (88%), mesmo com tratamento cirúrgico. Os fatores de risco ligados a esse tipo de infecção são: diabetes mellitus, insuficiência renal e insuficiência cardíaca. O microrganismo mais frequentemente implicado é o Staphylococcus aureus. A apresentação clínica pode ser muito variada, desde casos oligossintomáticos até sepse. Com relação ao diagnóstico, os métodos clássicos de imagem (ecocardiografia, angiotomografia aórtica) são altamente relevantes. Nas últimas décadas, a tomografia por emissão de pósitrons tem adquirido papel relevante nos casos que apresentam dúvidas diagnósticas como as do paciente, que será analisado.