Search

1036 Objectives The objective of this study was to develop a mSiO2/PSS/PDDA@BSA-Gd2O3-AS1411 molecular magnetic resonance imaging (mMRI) probe, which could recognize ccRCC sensitively and specifically. Methods For the fabrication of mMRI nanoprobes, BSA-Gd2O3 NPs were employed as MRI contrast agents and nanocarriers as well as AS1411 aptamer as target molecule. BSA-Gd2O3 NPs were assemblied onto mSiO2 with the help of anionic polyelectrolyte PSS and cationic polyelectrolyte PDDA layer by layer. FT-IR spectra and Zeta potential determination were used to monitor such assembly. In vitro cytotoxicity was evaluated by the MTT assay on a 786-0 cell line and a normal human umbilical vein endothelial cell line. For MRI diagnosis, 786-0 cells were incubated with PBS, mSiO2/PSS/PDDA@BSA-Gd2O3 and mSiO2/PSS/PDDA@BSA-Gd2O3-AS1411, respectively. NIH-3T3 cells were treated the same as control. The MR imaging was performed using 3.0-Tesla MRI. Results The successful assembly of this nanoprobe was confirmed by transmission electron microscopic (TEM), FT-IR spectroscopy and Zeta- potential analysis. The presence of PDDA and PSS could increase loading amount of BSA-Gd2O3 on mSiO2. The MTT assay showed no significant cytotoxicity on both 786-0 renal carcinoma cells and normal human umbilical vein endothelial cells. T1-weighted and T1-map imagings demonstrated that AS1411-Gd2O3@PDDA/PSS/mSiO2 nanoprobes could specifically targeted 786-0 cell lines. Conclusions In this study, mSiO2/PSS/PDDA@BSA-Gd2O3-AS1411 nanocomplex were prepared for the sensitive and specific mMRI probes of ccRCC. With our fabricated nanoprobes, ccRCC could be recognized specifically by MRI in vitro. Research Support Figure (a) Schematic illustration of the fabrication process of AS1411-Gd2O3@PDDA/PSS/mSiO2 nanoprobes. (b) T1-weighted and T1-map image of double distilled water, supernatant of Gd2O3@ mSiO2 nanoparticles, Gd2O3@ mSiO2 nanoparticles, Gd2O3@PDDA/PSS/mSiO2 nanoparticles with different concentrations at 3.0 T.(c) FT-IR spectra of AS1411/Gd2O3@PSS/PDDA/mSiO2 nanoprobes (red line), Gd2O3@PSS/PDDA/mSiO2 nanoparticles (black line), and AS1411 (red line). (d) T1-weighted(coronal, axial) and T1-map(axial) MR images of 786-0 renal carcinoma cells treated with AS1411-Gd2O3@PDDA/PSS/mSiO2 nanoprobe(200, 500, 1000µg/mL ), Gd2O3@PDDA/PSS/mSiO2 nanoparticles(200, 500, 1000µg/mL).

Accurate diagnosis of the nature of pancreatic cysts is challenging but more important than ever, in part because of the increasing number of incidental cystic findings in the pancreas. Preliminary data suggest that (18)F-FDG PET/CT may have a significant influence on clinical decision making, although its role is still evolving. Our aim was to prospectively compare the accuracy of combined (18)F-FDG PET and contrast-enhanced CT ((18)F-FDG PET/CT), multidetector CT (MDCT), and MR imaging in differentiating malignant from benign pancreatic cysts.Thirty-one consecutive patients with pancreatic cysts were enrolled in the study. They underwent a protocol including (18)F-FDG PET/CT, MDCT, and MR imaging combined with MR cholangiopancreatography, all of which were evaluated in a masked manner. The findings were confirmed macroscopically at surgery or histopathologic analysis (n = 22) or at follow-up (n = 9).Of the 31 patients, 6 had malignant and 25 had benign lesions. The diagnostic accuracy was 94% for (18)F-FDG PET/CT, compared with 77% and 87% for MDCT (P0.05) and MR imaging, respectively. (18)F-FDG PET/CT had a negative predictive value of 100% and a positive predictive value of 75% for pancreatic cysts. The maximum standardized uptake value was significantly higher in malignant (7.4 ± 2.6) than in benign lesions (2.4 ± 0.8) (P0.05). When the maximum standardized uptake value was set at 3.6, the sensitivity and specificity were 100% and 88%, respectively. Furthermore, when compared with MDCT and MR imaging, respectively, (18)F-FDG PET/CT altered the clinical management of 5 and 3 patients, respectively.(18)F-FDG PET/CT is an accurate imaging modality for differentiating between benign and malignant pancreatic cysts. We recommend the use of (18)F-FDG PET/CT in the evaluation of diagnostically challenging pancreatic cysts.

Although 6-(18)F-fluoro-L-dopa ((18)F-FDOPA) has been available to study the striatal dopaminergic system for more than 2 decades, the full potential of the tracer was not realized before the introduction of (18)F-FDOPA PET and PET/CT to image a variety of neuroendocrine tumors (NETs) and pancreatic beta-cell hyperplasia. Together with receptor-based imaging, (18)F-FDOPA offers a formerly unforeseen means to assist in the management of NETs and infants with persistent hyperinsulinemic hyperplasia. Institutions with special expertise in surgical, oncologic, and radiologic therapeutic modalities for NETs derive the highest benefit from (18)F-FDOPA PET/CT. (18)F-FDOPA-guided therapy may add to NET control by ensuring maximal cytoreduction.

The aim of this study was to evaluate 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5) labeled with 18F-fluorine to image hypoxia in patients with squamous cell carcinoma of the head and neck (HNSCC). Methods: Fifteen patients with HNSCC were studied. Measurement of tumor blood flow was followed by an 18F-EF5 PET/CT scan. On a separate day, 18F-FDG PET/CT was performed to determine the metabolically active tumor volume. In 6 patients, dynamic 18F-EF5 images of the head and neck area were acquired, followed by static images acquired at 1, 2, and 3 h after injection. In the remaining 9 patients, only static images were obtained. 18F-EF5 uptake in tumors was compared with that in neck muscle, and the 18F-EF5 findings were correlated with the 18F-FDG PET/CT studies. Results: A total of 13 primary tumors and 5 lymph node metastases were evaluated for their uptake of 18F-EF5. The median tumor-to-muscle 18F-EF5 uptake ratio (T/M) increased over time and was 1.38 (range, 1.1–3.2) 3 h after tracer injection. The median blood flow in tumors was 36.7 mL/100 g/min (range, 23.3–78.6 mL/100 g/min). Voxel-by-voxel analysis of coregistered blood flow and 18F-EF5 images revealed a distinct pattern, resulting in a T/M of 1.5 at 3 h to be chosen as a cutoff for clinically significant hypoxia. Fourteen of 18 tumors (78%) had subvolumes within the metabolically active tumor volumes with T/M greater than or equal to 1.5. Conclusion: On the basis of these data, the potential of 18F-EF5 to detect hypoxia in HNSCC is encouraging. Further development of 18F-EF5 for eventual targeting of antihypoxia therapies is warranted.