RESUMEN
PURPOSE: Current guidelines for sincalide-stimulated cholescintigraphy (SSC) call for a 60-minute sincalide infusion, and a gallbladder ejection fraction (GBEF) ≥38% is considered normal. In this retrospective study, we hypothesize that most patients reach a normal GBEF by 30 minutes. METHODS: Eligible patients had undergone a 60-minute SSC from January to December 2019. The clinical SSC data were previously processed on a Xeleris workstation (GE Healthcare). In subjects with GBEF ≥38% based on standard SSC, the GBEF at 20 minutes and 30 minutes were retrospectively calculated using manual pixel height measurements. Receiving operating characteristic was analyzed to determine the best GBEF cutoff at 30 minutes. RESULTS: Of 302 subjects, mean age of 46 ± 17 years, 33 (10.9%) showed an abnormal GBEF <38% suggestive of functional gallbladder disorder. In the remaining 269 patients (89.1%) with a normal GBEF, 60.6% and 86.6% reached a normal GBEF at 20 minutes and 30 minutes, respectively. Moreover, a GBEF threshold >29.1% at 30 minutes was associated with a negative predictive value of 99.6%, indicating that a 60-minute SSC was not necessary. The GBEF values were not associated with sex, age, patient symptoms, or type of referral. Manually calculated GBEFs on the time-activity curve showed excellent correlation with the primary values. We propose a modified workflow that splits the 60-minute SSC into two 30-minute image sets to allow for a screening GBEF at 30 minutes. If GBEF is >29.1% at 30 minutes, the second image set may be stopped, and the examination is complete. CONCLUSIONS: The majority of patients (77.2%) undergoing the standard 60-minute SSC reach a normal GBEF already by 30 minutes. The proposed workflow shortens the SCC procedure by 30 minutes, while maintaining high diagnostic accuracy and contributing to improved procedure efficiency and reduced patient discomfort as well as symptoms.
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Vaciamiento Vesicular , Sincalida , Adulto , Vesícula Biliar , Humanos , Persona de Mediana Edad , Cintigrafía , Estudios Retrospectivos , Flujo de TrabajoRESUMEN
Hybrid FDG PET/CT plays a vital role in oncologic imaging and has been widely adopted for the staging and restaging of a variety of malignancies. Its diagnostic value in urogenital malignancies is less well-known, not at least because of the variable FDG avidity of these tumor entities, the sites of these tumors, and technical challenges associated with sequential imaging of CT and PET. PET/CT interpretation thus can be especially challenging and is associated with many pitfalls, which can lead to both false-positive and false-negative diagnoses as well as incorrect assessment of metabolic change following therapy. Currently, FDG PET/CT is not the standard of care for the initial diagnosis or staging of early-stage or low-risk urogenital cancers; however, it can help evaluate distant metastatic disease, response to therapy, and disease recurrence in high-risk patients. Knowledge of imaging features of tumor metabolic avidity and pitfalls is essential for accurate interpretation.
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Tomografía Computarizada por Tomografía de Emisión de Positrones , Neoplasias Urogenitales , Fluorodesoxiglucosa F18 , Humanos , Recurrencia Local de Neoplasia , Tomografía de Emisión de Positrones , Neoplasias Urogenitales/diagnóstico por imagenRESUMEN
Neuroendocrine tumors (NETs) constitute a variety of neoplastic entities and exhibit variable degrees of neuroendocrine differentiation and phenotypes, as well as genetic profiles. Ga-DOTATATE PET is a novel imaging technique for NET. Although PET/CT is commonly utilized for oncologic imaging, PET/MRI is particularly suited for NETs, as MRI provides greater soft tissue contrast than CT, allowing for improved detection and characterization of NETs, particularly when liver metastasis is suspected or needs to be ruled out. The current pictorial review aims to illustrate the complementary advantages, as well as pitfalls of Ga-DOTATATE PET/MRI in the evaluation of NETs.
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Imagen por Resonancia Magnética/métodos , Imagen Multimodal/métodos , Tumores Neuroendocrinos/diagnóstico por imagen , Compuestos Organometálicos , Tomografía de Emisión de Positrones/métodos , Humanos , Tumores Neuroendocrinos/patologíaRESUMEN
A 72-year-old man with a history of T1cN0M0 prostate adenocarcinoma and rising prostate-specific antigen underwent a fluciclovine PET/CT scan that showed high uptake in several para-aortic nodes, suspicious for prostate cancer. A right upper lobe single pulmonary nodule (SPN), demonstrated only mild uptake, which raised the suspicion for a lung primary. Subsequent FDG PET/CT showed high uptake in the SPN, revealing poorly differentiated adenocarcinoma at biopsy, but with no abnormal uptake in the para-aortic nodes. This case highlights the complementary potential of fluciclovine and FDG PET in patients with a history of prostate cancer biochemical recurrence and SPN.