Visualization of Activated BAT in Mice, with FDG-PET and its relation to UCP1

The visualization of symmetric structure by [18F]-FluoroDeoxyGlucose-Positron Emission Tomography (FDG-PET), corresponding to adipose density in computed tomography (CT), has led to the idea that Brown Adipose Tissue (BAT) could be present in adult human. This article studies the FDG uptake in a mice model deficient on Uncoupling Protein 1 (UCP1), in a simple thermal activation protocol. Methods: FDG were injected in mice, control and knock out (K.O.) for the UCP1. Before imaging mice were placed either in cold or warm environment. BAT uptake was evaluated by ratio named RISC. Results: In warm condition, mean value of the Ratio of Inter-Scapular uptake (RISC) was 1.34 +/﹣ 0.27. After cold exposure, RISC increased 2 fold for control mice, male K.O. did not increase their RISC, female K.O. increased their RISC up to 2.45. Conclusion: Our study brought a further confirmation that FDG-PET visualised activated Brown Adipose Tissue. It gives a direct proof of the role of UCP1 in this process. The FDG uptake by cold female K.O. mice was unexpected

Impact of 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) in recurrent colorectal cancer

Purpose: The aim of the study was to evaluate the diagnostic performance, the prognosis factors and the therapeutic impact of 18F-FDG positron emission tomography (FDG-PET) in the detection of recurrent colorectal cancers. Methods: Sixty PET/CT with 18F-FDG and CT were performed in 52 patients, at the Paul Papin cancer center between 2003 and 2005, following suspicion of colorectal cancer relapse. The FDG-PET impact on the clinical management was studied by examination of multidisciplinary concertations results. Survival analysis were realized with a mean follow up of 2.2 years. Results: Recurrence was confirmed for 50 explorations by histologic (n = 32), radiologic (n = 14) or clinical (n = 4) findings. Twenty patients died during the time of the study. On a patient based analysis, FDG-PET sensitivity, specificity and overall accuracy were 90, 90, 90% respectively compared with 74, 50 and 70% for CT. FDG-PET changed the clinical management in 18 cases (30%). A positive FDG-PET signal, more than one hepatic lesion, more than two lymph node lesions detected on FDG-PET and more than two hepatic lesions on CT were characterized as bad prognostic factors for survival. Multivariate analysis showed that the only independent bad prognostic factor was the FDG-PET detection of more than two liver lesions. Conclusion: These results confirmed the important impact of FDG-PET in the clinical management of patients with a suspected recurrence of colorectal cancer

Clinical evaluation of General Electric new Swiftscan solution in bone scintigraphy on NaI-camera: A head to head comparison with Siemens Symbia.

PurposeThe General Electric (GE) Swiftscan solution combines a new Low Energy High Resolution and Sensitivity collimator (LEHRS) with image processing (Clarity 2D) and tomographic step and shoot continuous mode. The aim of this study was to compare clinical and physical performances of this new technology in bone scintigraphy.MethodsPhysical phantom measurements were performed using GE LEHRS, GE Low Energy High Resolution (LEHR) and Siemens LEHR collimators. These measurements were associated with a prospective clinical study. Sixty-seven patients referred for bone scintigraphy were enrolled from February to July 2018. Each patient underwent two acquisitions consecutively on GE and Siemens gamma camera, using respectively Swiftscan solution and LEHR collimator.ResultsOn planar acquisitions, maximum sensitivity was 100 cts/MBq for Siemens LEHR. GE SwiftScan LEHRS and GE LEHR maximum sensitivity were respectively 9% and 22% lower. Using Clarity 2D, GE Swiftscan LEHRS spatial resolution was the best with 9.2 mm versus 10.1 mm and 10.6 mm for GE LEHR and Siemens LEHR collimators. In tomographic mode, the sensitivity of GE Swiftscan solution was superior to both LEHR systems (16% and 25% respectively for Siemens and GE). There was no significant difference in spatial resolution. In clinical use, signal was higher on Siemens system and noise was lower on GE Swiftscan solution. Contrast-to-noise ratios were not significantly different between the two systems. There was a significant image quality improvement with GE SwiftScan in planar images and in whole body scan. No significant difference in image quality was observed on SPECT images.ConclusionNew GE SwiftScan collimator design improved sensitivity compared to "classical" GE LEHR collimator without compromising resolution. GE SwiftScan solution enhances planar image quality with a better Clarity 2D resolution recovery and noise treatment. In SPECT mode, GE SwiftScan solution improves volumetric sensitivity without significant impact on image quality, and could lead to time or dose reduction