RESUMO
A Schmorl's node is a common incidental finding encountered during radiologic imaging. Despite the vertebral body being a common site of metastatic disease, a lytic lesion adjacent to an endplate with typical imaging features can often confidently be called a Schmorl's node. This is a case report of a patient with a single well-defined FDG-avid papillary thyroid carcinoma metastasis to the spine that had imaging findings characteristic of a Schmorl's node on CT and MRI. This case is important to consider as it demonstrates that the imaging characteristics of metastatic disease and Schmorl's nodes can overlap.
RESUMO
Fluorine-18 labeled 2-fluoro-8-hydroxyquinoline ([(18)F]CABS13) is a promising positron emission tomography (PET) radiopharmaceutical based on a metal chelator developed to probe the "metal hypothesis of Alzheimer's disease". Herein, a practical radiosynthesis of [(18)F]CABS13 was achieved by radiofluorination followed by deprotection of an O-benzyloxymethyl group. Automated production and formulation of [(18)F]CABS13 resulted in 19 ± 5% uncorrected radiochemical yield, relative to starting [(18)F]fluoride, with ≥95% chemical and radiochemical purities, and high specific activity (>2.5 Ci/µmol) within 80 min. Temporal PET neuroimaging studies were carried out in female transgenic B6C3-Tg(APPswe,PSEN 1dE9)85Dbo/J (APP/PS1) and age-matched wild-type (WT) B6C3F1/J control mice at 3, 7, and 10 months of age. [(18)F]CABS13 showed an overall higher uptake and retention of radioactivity in the central nervous system of APP/PS1 mice versus WT mice with increasing age. However, PET/magnetic resonance imaging in normal nonhuman primates revealed that the tracer had low uptake in the brain and rapid formation of a hydrophilic radiometabolite. Identification of more metabolically stable (18)F-hydroxyquinolines that can be readily accessed by the radiochemical strategy presented herein is underway.
Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Envelhecimento , Doença de Alzheimer/fisiopatologia , Precursor de Proteína beta-Amiloide/genética , Animais , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Feminino , Radioisótopos de Flúor/química , Humanos , Imageamento por Ressonância Magnética , Camundongos , Camundongos Transgênicos , Imagem Multimodal , Papio anubis , Tomografia por Emissão de Pósitrons , Presenilina-1/genética , Quinolinas/síntese química , Quinolinas/química , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/químicaRESUMO
PURPOSE: This study attempts to establish a quantitative link between a patient's body mass index (BMI), the delivered radiation dose, and the image noise. METHODS: The CARE Dose4D computed tomography (CT) acquisitions from 206 patients undergoing "eyes-to-thighs" contrast-enhanced positron emission tomography/CT studies were retrospectively examined. Computed tomography dose index volume (CTDIVOL), mAs, and dose-length product were recorded from the dose report card. The image noise was quantified by evaluating the SD of regions of interest placed over the contrast enhanced aorta. RESULTS: The multivariate regressions f(BMI, mAs) and f(BMI, CTDIVOL) had R values of 0.4840 and 0.4802, respectively. Unpaired t tests demonstrate that statistically significant difference in image noise required more than 12.17 kg/m of separation between the average BMI values for the groups compared. CONCLUSIONS: The evaluation of image noise with BMI and CTDIVOL or mAs is a means to evaluate the consistency of dose modulation software. There is considerable variability in the radiation dose generated by the CARE Dose4D software.
