Vulnerable plaque imaging using 18F-sodium fluoride positron emission tomography

Positron emission tomography (PET) with (18)F-sodium fluoride ((18)F-NaF) has emerged as a promising non-invasive imaging modality to identify high-risk and ruptured atherosclerotic plaques. By visualizing microcalcification, (18)F-NaF PET holds clinical promise in refining how we evaluate coronary artery disease, shifting our focus from assessing disease burden to atherosclerosis activity. In this review, we provide an overview of studies that have utilized (18)F-NaF PET for imaging atherosclerosis. We discuss the associations between traditional coronary artery disease measures (risk factors) and (18)F-NaF plaque activity. We also present the data on the histological validation as well as show how (18)F-NaF uptake is associated with plaque morphology on intravascular and CT imaging. Finally, we discuss the technical challenges associated with (18)F-NaF coronary PET highlighting recent advances in this area

Quantification of FDG PET studies using standardised uptake values in multi-centre trials: effects of image reconstruction, resolution and ROI definition parameters.

Contains fulltext : 52887.pdf (publisher's version ) (Closed access)PURPOSE: Standardised uptake values (SUVs) depend on acquisition, reconstruction and region of interest (ROI) parameters. SUV quantification in multi-centre trials therefore requires standardisation of acquisition and analysis protocols. However, standardisation is difficult owing to the use of different scanners, image reconstruction and data analysis software. In this study we evaluated whether SUVs, obtained at three different institutes, may be directly compared after calibration and correction for inter-institute differences. METHODS: First, an anthropomorphic thorax phantom containing variously sized spheres and activities, simulating tumours, was scanned and processed in each institute to evaluate differences in scanner calibration. Secondly, effects of image reconstruction and ROI method on recovery coefficients were studied. Next, SUVs were derived for tumours in 23 subjects. Of these 23 patients, four and ten were scanned in two institutes on an HR+ PET scanner and nine were scanned in one institute on an ECAT EXACT PET scanner. All phantom and clinical data were reconstructed using iterative reconstruction with various iterations, with both measured (MAC) and segmented attenuation correction (SAC) and at various image resolutions. Activity concentrations (AC) or SUVs were derived using various ROI isocontours. RESULTS: Phantom data revealed differences in SUV quantification of up to 30%. After application-specific calibration, recovery coefficients obtained in each institute were equal to within 15%. Varying the ROI isocontour value resulted in a predictable change in SUV (or AC) for both phantom and clinical data. Variation of image resolution resulted in a predictable change in SUV quantification for large spheres/tumours (>5 cc) only. For smaller tumours (<2 cc), differences of up to 40% were found between high (7 mm) and low (10 mm) resolution images. Similar differences occurred when data were reconstructed with a small number of iterations. Finally, no significant differences between MAC and SAC reconstructed data were observed, except for tumours near the diaphragm. CONCLUSION: Standardisation of acquisition, reconstruction and ROI methods is preferred for SUV quantification in multi-centre trials. Small unavoidable differences in methodology can be accommodated by performing a phantom study to assess inter-institute correction factors

Intraoperative PTH monitoring during Parathyroidectomy:the need for stricter criteria to detect multiglandular disease

PURPOSE: Usefulness of rapid intraoperative parathyroid hormone assay (RI-PTH) for diagnosis of multiglandular disease during parathyroidectomy is still debated. MATERIALS AND METHODS: Two hundred seven patients were selected for focused parathyroidectomy for a suspicious single adenoma. RI-PTH results were interpreted on the basis of our criteria for prediction of multiglandular disease (a < 50% drop from the highest pre-excision level and/or a T20 concentration higher than reference range and/or >7.5 ng/L higher than the T10). The results of these criteria were compared with the Miami Criterion (MC). RESULTS: One hundred ninety-seven uniglandular disease and ten multiglandular disease were found. Our criteria identified all but one patient with multiglandular disease (false positive (FP) rate 0.5%; specificity 90%). On the basis of MC, RI-PTH monitoring would have resulted in five FP results, with a specificity of 50%. CONCLUSIONS: Despite the higher rate of unnecessary bilateral exploration, our criteria results in a lower FP, markedly reducing the risk of missing multiglandular disease