Dose Reduction in Pediatric Oncology Patients with Delayed Total-Body [18F]FDG PET/CT.

Our aim was to define a lower limit of reduced injected activity in delayed [18F]FDG total-body (TB) PET/CT in pediatric oncology patients. Methods: In this single-center prospective study, children were scanned for 20 min with TB PET/CT, 120 min after intravenous administration of a 4.07 ± 0.49 MBq/kg dose of [18F]FDG. Five randomly subsampled low-count reconstructions were generated using », ⅛, [Formula: see text], and [Formula: see text] of the counts in the full-dose list-mode reference standard acquisition (20 min), to simulate dose reduction. For the 2 lowest-count reconstructions, smoothing was applied. Background uptake was measured with volumes of interest placed on the ascending aorta, right liver lobe, and third lumbar vertebra body (L3). Tumor lesions were segmented using a 40% isocontour volume-of-interest approach. Signal-to-noise ratio, tumor-to-background ratio, and contrast-to-noise ratio were calculated. Three physicians identified malignant lesions independently and assessed the image quality using a 5-point Likert scale. Results: In total, 113 malignant lesions were identified in 18 patients, who met the inclusion criteria. Of these lesions, 87.6% were quantifiable. Liver SUVmean did not change significantly, whereas a lower signal-to-noise ratio was observed in all low-count reconstructions compared with the reference standard (P < 0.0001) because of higher noise rates. Tumor uptake (SUVmax), tumor-to-background ratio, and total lesion count were significantly lower in the reconstructions with [Formula: see text] and [Formula: see text] of the counts of the reference standard (P < 0.001). Contrast-to-noise ratio and clinical image quality were significantly lower in all low-count reconstructions than with the reference standard. Conclusion: Dose reduction for delayed [18F]FDG TB PET/CT imaging in children is possible without loss of image quality or lesion conspicuity. However, our results indicate that to maintain comparable tumor uptake and lesion conspicuity, PET centers should not reduce the injected [18F]FDG activity below 0.5 MBq/kg when using TB PET/CT in pediatric imaging at 120 min after injection.

Balloon-Expandable Cheatham-Platinum Stents Versus Self-Expandable Nitinol Stents in Coarctation of Aorta: A Randomized Controlled Trial.

OBJECTIVES: This study sought to compare the safety and efficacy of the balloon-expandable stent (BES) and the self-expandable stent (SES) in the endovascular treatment of coarctation of aorta. BACKGROUND: Coarctoplasty with stents has conferred promising results. Although several nonrandomized studies have approved the safety and efficacy of the BES and the SES, no high-quality evidence exists for this comparison. METHODS: In the present open-label, parallel-group, blinded endpoint randomized pilot clinical trial, adult patients with de novo native aortic coarctation were randomized into Cheatham-platinum BES and uncovered nitinol SES groups. The primary outcome of the study was a composite of procedural and vascular complications. The secondary outcomes of the study consisted of the incidence of aortic recoarctation, thoracic aortic aneurysm/pseudoaneurysm formation, and residual hypertension at a 12-month follow-up. RESULTS: Among 105 patients who were screened between January 2017 and December 2019, 92 eligible patients (32 women [34.8%]) with a median age of 30 years (IQR: 20-36 years) were randomized equally into the BES and SES groups. The composite of procedural and vascular complications occurred in 10.9% of the BES group and 2.2% of the SES group (odds ratio: 0.18; 95% CI: 0.02-1.62; P = 0.20). Aortic recoarctation occurred in 5 patients (5.4%), 3 patients (6.5%) in the BES group and 2 patients (4.3%) in the SES group (odds ratio: 0.65; 95% CI: 0.10-4.09; P = 0.64). Only 1 patient (1.1%) was complicated by aortic pseudoaneurysm. Hypertension control was achieved in 50% of the study population, with an equal distribution in the 2 study groups at the 12-month follow-up. CONCLUSIONS: Both the BES and the SES were safe and effective in the treatment of native coarctation.

Rivaroxaban in patients undergoing surgical mitral valve repair.

In patients undergoing mitral valve repair (MVre), a 3-month course of anticoagulation is currently recommended. The role of the non-vitamin K antagonist oral anticoagulants has here been scarcely studied. In the present mixed cohort study, the safety and efficacy of rivaroxaban (prospective analysis) were compared with those of warfarin (retrospective analysis) in patients undergoing MVre. Anticoagulation therapy was continued for at least 3 months, and the patients were followed for 1 year following surgery. The present study recruited 736 patients undergoing MVre with or without concomitant coronary artery bypass or surgical repair on the other valves. Concomitant valvular replacement and severe chronic kidney diseases were the most important exclusion criteria. The final analysis was conducted on 153 patients treated with rivaroxaban and 144 patients treated with warfarin. Dissimilarities in baseline characteristics necessitated propensity score matching, in which 104 patients in each group were compared. No major bleeding or cerebrovascular accident occurred during the 1-year follow-up. Clinically relevant non-major bleeding was reported in 2 patients in the rivaroxaban group and 4 patients in the warfarin group, a difference non-statistically significant before and after propensity score matching (P = 0.371 and P = 0.407, respectively). The type of anticoagulation did not predict the 1-year outcome (HR 2.165, 95% CI 0.376 to 12.460; P = 0.387). In this mixed cohort study, rivaroxaban was both safe and efficient in patients with MVre. Such preliminary results should prompt larger randomized controlled trials.