Unlabelled: In this study, factor analysis of dynamic structures (FADS) was used to extract the "pure" blood-pool time-activity curves (TACs) and to generate parametric myocardial blood flow (MBF) images (pixel unit: ml/min/g).
Methods: Ten dynamic 13N-ammonia dog PET studies (three baseline, five hyperemia and two occlusion) were included. Three factors (TACs) and their corresponding factor images (the right ventricular and left ventricular blood pools and myocardial activities) were extracted from each study. The left ventricular factors matched well with the plasma TACs. The factor images of myocardium were then converted to a parametric images of MBF using a relationship derived from a two-compartment model.
Results: MBF estimates obtained from FADS correlated well with MBF estimates obtained with the two-compartment model (r = 0.98, slope = 0.84) and microsphere techniques (r = 0.96, slope = 0.94). FADS-generated MBF parametric images have better image quality and lower noise levels compared to those generated with Patlak graphical analysis.
Conclusion: Regional MBF can be measured accurately and noninvasively with 13N-ammonia dynamic PET imaging and FADS. The method is simple, accurate and produces parametric images of MBF without requiring blood sampling and spillover correction.
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J Nucl Med
January 2025
Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
Cognitive flexibility is the ability to appropriately adapt one's thinking and behavior to changing environmental demands and is conceptualized as an aspect of executive function. The dopamine system has been implicated in cognitive flexibility; however, a direct, that is, neurochemical, link to cognitive flexibility has not been shown yet. The aim of this study was, therefore, to investigate how cognitive flexibility is mediated by dopaminergic signaling in the ventromedial prefrontal cortex (vmPFC).
View Article and Find Full Text PDFEur Heart J Cardiovasc Imaging
January 2025
Department of Engineering and Architecture, University of Trieste, Trieste, Italy.
Insights Imaging
January 2025
Department of Radiology, The First Affiliated Hospital of Soochow University, Suzhou, China.
Purposes: The presence of clinically significant prostate cancer (csPCa) is equivocal for patients with prostate imaging reporting and data system (PI-RADS) category 3. We aim to develop deep learning models for re-stratify risks in PI-RADS category 3 patients.
Methods: This retrospective study included a bi-parametric MRI of 1567 consecutive male patients from six centers (Centers 1-6) between Jan 2015 and Dec 2020.
Med Phys
January 2025
Deparment of Radiation Oncology, Duke University, Durham, North Carolina, USA.
Background: Stereotactic radiosurgery (SRS) is widely used for managing brain metastases (BMs), but an adverse effect, radionecrosis, complicates post-SRS management. Differentiating radionecrosis from tumor recurrence non-invasively remains a major clinical challenge, as conventional imaging techniques often necessitate surgical biopsy for accurate diagnosis. Machine learning and deep learning models have shown potential in distinguishing radionecrosis from tumor recurrence.
View Article and Find Full Text PDFBMC Pulm Med
January 2025
State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease & National Center for Respiratory Medicine & Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China.
Background: Studies on consistency among spirometry, impulse oscillometry (IOS), and histology for detecting small airway dysfunction (SAD) remain scarce. Considering invasiveness of lung histopathology, we aimed to compare spirometry and IOS with chest computed tomography (CT) for SAD detection, and evaluate clinical characteristics of subjects with SAD assessed by these three techniques.
Methods: We collected baseline data from the Early COPD (ECOPD) study.
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