Purpose
In cancer of unknown primary (CUP), positron emission tomography/computed tomography (PET/CT) with the glucose analog [18F]FDG represents the standard imaging approach for localization of the malignant primary. Frequently, however, [18F]FDG PET/CT cannot precisely distinguish between small occult tumors and chronic inflammation, especially in Waldeyer’s tonsillar ring. To improve the accuracy for detecting primary tumors in the Waldeyer’s tonsillar ring, the novel PET tracer [68Ga]Ga-FAPI-4 for specific imaging of fibroblast activation protein (FAP) expression was used as a more specific target for cancer imaging.
Methods
Eight patients with suspicion of a malignant tumor in Waldeyer’s tonsillar ring or a CUP syndrome were examined. PET/CT scans with [18F]-FDG and [68Ga]Ga-FAPI-4 were performed for pre-operative tumor localization. After surgical resection, histopathological and immunohistochemical results were compared to PET/CT findings.
Results
Histopathology revealed a palatine or lingual tonsil carcinoma in all patients. In case of lymph node metastases smaller than 7 mm in size, the [18F]FDG PET/CT detection rate of cervical lymph node metastases was higher than that of [68Ga]FAPI PET/CT, while both tracers identified the primary tumors in all eight cases. The size of the primary and the lymph node metastases was directly correlated to the respective FAP expression, as detected by immunohistochemistry. The mean SUVmax for the primary tumors was 21.29 ± 7.97 for 18F-FDG and 16.06 ± 6.29 for 68Ga-FAPI, respectively (p = 0.2). The mean SUVmax for the healthy contralateral tonsils was 8.38 ± 2.45 for [18F]FDG and 3.55 ± 0.47 for [68Ga]FAPI (p < 0.001). The SUVmax ratio of [68Ga]FAPI was significantly different from [18F] FDG (p = 0.03). Mean TBRmax for the [68Ga]Ga-FAPI-4 tracer was markedly higher in comparison to [18F]FDG (10.90 vs. 4.11).
Conclusion
Non-invasive imaging of FAP expression by [68Ga]FAPI PET/CT resulted in a better visual detection of the malignant primary in CUP, as compared to [18F]FDG imaging. However, the detection rate of lymph node metastases was inferior, presumably due to low FAP expression in small metastases. Nevertheless, by offering a detection method for primary tumors with the potential of lower false positive rates and thus avoiding biopsies, patients with CUP syndrome may benefit from [68Ga]FAPI PET/CT imaging.
Congenital aneurysm or enlargement of the right atrium is a rare condition. Two
children operated on at the age of 14 months and 11 years old for congenital
aneurysm of the right atrium are reported. Both presented cardiomegaly and
symptoms of paroxysmal supraventricular tachycardia. Diagnosis was established
by echocardiography. Surgical resection was successful. Both patients are free
of symptoms and their chest X-ray and echocardiogram are normal. The first
patient is now in her 17
th
postoperative year. The patients'
evolution suggests that the surgery is a curative procedure.
RESUMOIntrodução: O acesso através da punção da artéria axilar (AAx) tem sido utilizado em adultos com bons resultados, porém seu uso em neonatos e lactentes jovens tem sido pouco relatado. Nosso objetivo foi relatar a experiência inicial com o uso desse acesso em diferentes intervenções nessa faixa etária de pacientes. Método: De janeiro de 2009 a setembro de 2010 foram incluídas 11 crianças submetidas a diferentes procedimentos intervencionistas realizados através de punção da AAx. O procedimento foi realizado com agulha 21 G, sendo utilizados introdutores 4 F ou 5 F pediátricos. Resultados: A média de idade foi de 26 ± 12 dias e o peso médio, de 4,2 ± 1,7 kg. Os procedimentos intervencionistas realizados foram: implante de stent no canal arterial (6), valvoplastia aórtica (1), angioplastia aórtica (2), implante de stent em Blalock-Taussig (1), e redilatação do stent do canal arterial (1). A punção da AAx direita foi realizada com sucesso em todos os pacientes e sem dificuldade técnica. Os tempos médios do procedimento e da fluoroscopia foram de, respectivamente, 52 ± 15 minutos e 13 ± 4 minutos. Apenas um paciente teve como complicação um pneumotórax sem repercussão hemodinâmica, e os demais pacientes não apresentaram intercorrências. Não houve complicações isquêmicas nem neurológicas no membro puncionado. O tempo médio de internação na Unidade de Tratamento Intensivo (UTI) foi de 48 ± 16 horas. Não houve mortalidade durante os procedimentos intervencionistas e um paciente faleceu na UTI cinco dias após por sepse. Conclusão: O acesso axilar obtido por punção demonstrou ser uma alternativa segura e eficaz para a realização de diferentes procedimentos intervencionistas em neonatos e lactentes com cardiopatias congênitas.
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