43 research outputs found
CT-perfusion in peripheral arterial disease - Correlation of baseline with post-interventional perfusion parameters
No full textCT-perfusion in pheripheral arterial disease-Correlation of baseline with post-interventional perfusion parameters
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Deep learning–based time-of-flight (ToF) image enhancement of non-ToF PET scans
No full textPurpose
To improve the quantitative accuracy and diagnostic confidence of PET images reconstructed without time-of-flight (ToF) using deep learning models trained for ToF image enhancement (DL-ToF).
Methods
A total of 273 [18F]-FDG PET scans were used, including data from 6 centres equipped with GE Discovery MI ToF scanners. PET data were reconstructed using the block-sequential-regularised-expectation–maximisation (BSREM) algorithm with and without ToF. The images were then split into training (n = 208), validation (n = 15), and testing (n = 50) sets. Three DL-ToF models were trained to transform non-ToF BSREM images to their target ToF images with different levels of DL-ToF strength (low, medium, high). The models were objectively evaluated using the testing set based on standardised uptake value (SUV) in 139 identified lesions, and in normal regions of liver and lungs. Three radiologists subjectively rated the models using testing sets based on lesion detectability, diagnostic confidence, and image noise/quality.
Results
The non-ToF, DL-ToF low, medium, and high methods resulted in − 28 ± 18, − 28 ± 19, − 8 ± 22, and 1.7 ± 24% differences (mean; SD) in the SUVmax for the lesions in testing set, compared to ToF-BSREM image. In background lung VOIs, the SUVmean differences were 7 ± 15, 0.6 ± 12, 1 ± 13, and 1 ± 11% respectively. In normal liver, SUVmean differences were 4 ± 5, 0.7 ± 4, 0.8 ± 4, and 0.1 ± 4%. Visual inspection showed that our DL-ToF improved feature sharpness and convergence towards ToF reconstruction. Blinded clinical readings of testing sets for diagnostic confidence (scale 0–5) showed that non-ToF, DL-ToF low, medium, and high, and ToF images scored 3.0, 3.0, 4.1, 3.8, and 3.5 respectively. For this set of images, DL-ToF medium therefore scored highest for diagnostic confidence.
Conclusion
Deep learning–based image enhancement models may provide converged ToF-equivalent image quality without ToF reconstruction. In clinical scoring DL-ToF-enhanced non-ToF images (medium and high) on average scored as high as, or higher than, ToF images. The model is generalisable and hence, could be applied to non-ToF images from BGO-based PET/CT scanners.</p
Feasibility and preliminary results of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction
No full textPrevalence and prognostic value of increased uptake in bone SPECT/CT in asymptomatic wrists
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A new SPECT/CT reconstruction algorithm: reliability and accuracy in clinical routine for non-oncologic bone diseases
No full text[18F]Fluorocholine Uptake of Parathyroid Adenoma Is Correlated with Parathyroid Hormone Level
No full textPURPOSE: The aim of the study was to investigate the relationship between [F]fluoromethyl-dimethyl-2-hydroxyethylammonium ([F]FCh) positron emission tomography (PET) parameters, laboratory parameters, and postoperative histopathological results in patients with primary hyperparathyroidism (pHPT) due to parathyroid adenomas.
PROCEDURES: This retrospective study was conducted in 52 patients with biochemically proven pHPT. [F]FCh-PET parameters (maximum standardized uptake value: SUV in early phase (after 2Â min) and late phase (after 50Â min), metabolic volume, and adenoma-to-background ratio (ABR), preoperative laboratory results (PTH and serum calcium concentration), and postoperative histopathology (location, size, volume, and weight of adenoma) were assessed. Relationship of PET parameters, laboratory parameters, and histopathological parameters was assessed using the Mann-Whitney U test and Spearman correlation coefficient. MRI characteristics of parathyroid adenomas were also analyzed.
RESULTS: The majority of patients underwent a PET/MR scan, 42 patients (80.7 %); 10 patients (19.3 %) underwent PET/CT. We found a strong positive correlation between late-phase SUV and preoperative PTH level (r = 0.768, p < 0.001) and between late-phase ABR and preoperative PTH level (r = 0.680, p < 0.001). The surgical specimen volume was positively correlated with the PET/MR lesion volume (r = 0.659, p < 0.001). No significant association was observed between other [F]FCh-PET parameters, laboratory parameters, and histopathological findings. Cystic adenomas were larger than non-cystic adenomas (p = 0.048).
CONCLUSIONS: [F]FCh uptake of parathyroid adenomas is strongly correlated with preoperative PTH serum concentration. Therefore, the preoperative PTH level might potentially be able to predict success of [F]FCh-PET imaging in hyperparathyroidism, with higher lesion-to-background ratios being expected in patients with high PTH. PET/MR is accurate in estimating the volume of parathyroid adenomas
