Ronald Borra

This study evaluated the performance of the Biograph Vision digital PET/CT system according to the NEMA NU 2-2012 standard (published by the National Electrical Manufacturers Association [NEMA]) to allow for a reliable, reproducible, and intersystem-comparable performance measurement. <b>Methods:</b> The new digital PET/CT system features silicon photomultiplier–based detectors with 3.2-mm lutetium oxyorthosilicate crystals and full coverage of the scintillator area. The PET components incorporate 8 rings of 38 detector blocks, and each block contains 4 × 2 mini blocks. Each mini block consists of a 5 × 5 lutetium oxyorthosilicate array of 3.2 × 3.2 × 20 mm crystals coupled to a silicon photomultiplier array of 16 × 16 mm, resulting in an axial field of view of 26.1 cm. In this study, PET/CT system performance was evaluated for conformation with the NEMA NU 2-2012 standard, with additional measurements described in the new NEMA NU 2-2018 standard. Spatial resolution, sensitivity, count-rate performance, accuracy of attenuation and scatter correction, image quality, coregistration accuracy, and time-of-flight performance were determined. Measurements were directly compared with results from its predecessor, the Biograph mCT Flow, using existing literature. Moreover, feasibility to comply with the European Association of Nuclear Medicine Research Ltd. (EARL) criteria was evaluated, and some illustrative patient PET images were obtained. <b>Results:</b> The Biograph Vision showed a transverse and axial spatial resolution of 3.6 and 3.5 mm, respectively, in full width at half maximum at a 1-cm offset from the center of the field of view (measured with a ²²Na 0.25-mm point source), a NEMA sensitivity of 16.4 kcps/MBq, and a NEMA peak noise-equivalent count-rate of 306 kcps at 32 kBq/mL. Time-of-flight resolution varied from 210 to 215 as count-rate increased up to the peak noise-equivalent count-rate. The overall image contrast seen with the NEMA image quality phantom ranged from 77.2% to 89.8%. Furthermore, the system was able to comply with the current and future EARL performance criteria. <b>Conclusion:</b> The Biograph Vision outperforms the analog Biograph mCT Flow, and the system is able to meet European harmonizing performance standards.

Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception.

In Brief Objective: To prospectively compare the accuracy of combined positron emission tomography/computed tomography using 18F-fluorodeoxyglucose (FDG-PET/CT), multidetector row computed tomography (MDCT), and magnetic resonance imaging (MRI) in the evaluation of patients with suspected pancreatic malignancy. Summary Background Data: FDG-PET/CT imaging is increasingly used for staging of pancreatic cancer. Preliminary data suggest a significant influence of FDG-PET/CT on treatment planning, although its role is still evolving. Methods: Thirty-eight consecutive patients with suspicion of pancreatic malignancy were enrolled. Patients underwent a protocol including FDG-PET/CT, MDCT, and MRI combined with magnetic resonance cholangiopancreatography, all of which were blindly evaluated. The findings were confirmed macroscopically at operation and/or by histopathologic analysis (n = 29) or follow-up (n = 9). Results of TNM classification of different imaging methods were compared with clinical TNM classification. Results: Pancreatic adenocarcinoma was diagnosed in 17 patients, neuroendocrine tumor in 3, mass-forming pancreatitis in 4, cystic lesion in 6, and fibrosis in 2. Six patients had a finding of a normal pancreas. The diagnostic accuracy of FDG-PET/CT for pancreatic malignancy was 89%, compared with 76% and 79% for MDCT and MRI, respectively. In the differential diagnosis of suspected malignant biliary stricture at endoscopic retrograde cholangiopancreaticography (n = 21), FDG-PET/CT had a positive predictive value of 92%. In 17 patients with advanced pancreatic adenocarcinoma, FDG-PET/CT had a sensitivity of 30% for N- and 88% for M-staging. Both MDCT and MRI had sensitivities of 30% for N- and 38% for M-staging. Furthermore, the clinical management of 10 patients (26%) was altered after FDG-PET/CT. Conclusion: FDG-PET/CT was more sensitive than conventional imaging in the diagnosis of both primary pancreatic adenocarcinoma and associated distant metastases. In contrast, the sensitivity of FDG-PET/CT was poor in detecting local lymph node metastasis, which would have been important for an assessment of resectability. We recommend the use of FDG-PET/CT in the evaluation of diagnostically challenging cases, especially in patients with biliary strictures without evidence of malignancy in conventional imaging. The aim of the study was to prospectively compare 18F-fluorodeoxyglucose positron emission tomography or computed tomography, multidetector row computed tomography, and magnetic resonance imaging in the diagnosis of pancreatic cancer. In group of 38 patients, 18F-fluorodeoxyglucose positron emission tomography or computed tomography was more sensitive than conventional imaging in the diagnosis of both primary pancreatic adenocarcinoma and associated distant metastases.