MR imaging and PET/CT are integrated in the work-up of head and neck cancer patients. The hybrid imaging technology (18)F-FDG-PET/MR imaging combining morphological and functional information might be attractive in this patient population. The aim of the study was to compare whole-body (18)F-FDG-PET/MR imaging and (18)F-FDG-PET/CT in patients with head and neck cancer, both qualitatively in terms of lymph node and distant metastases detection and quantitatively in terms of standardized uptake values measured in (18)F-FDG-avid lesions. Fourteen patients with head and neck cancer underwent both whole-body PET/CT and PET/MR imaging after a single injection of (18)F-FDG. Two groups of readers counted the number of lesions on PET/CT and PET/MR imaging scans. A consensus reading was performed in those cases in which the groups disagreed. Quantitative standardized uptake value measurements were performed by placing spheric ROIs over the lesions in 3 different planes. Weighted and unweighted κ statistics, correlation analysis, and the Wilcoxon signed rank test were used for statistical analysis. κ statistics for the number of head and neck lesion lesions counted (pooled across regions) revealed interreader agreement between groups 1 and 2 of 0.47 and 0.56, respectively. Intrareader agreement was 0.67 and 0.63. The consensus reading provided an intrareader agreement of 0.63. For the presence or absence of metastasis, interreader agreement was 0.85 and 0.70. The consensus reading provided an intrareader agreement of 0.72. The correlations between the maximum standardized uptake value in (18)F-FDG-PET/MR imaging and (18)F-FDG-PET/CT for primary tumors and lymph node and metastatic lesions were very high (Spearman r = 1.00, 0.93, and 0.92, respectively). In patients with head and neck cancer, (18)F-FDG-PET/MR imaging and (18)F-FDG-PET/CT provide comparable results in the detection of lymph node and distant metastases. Standardized uptake values derived from (18)F-FDG-PET/MR imaging can be used reliably in this patient population.

Usefulness of MRI in takotsubo cardiomyopathy: a review of the literature

Purpose: The aims of this study were to perform a comprehensive review and meta-analyses and to report pooled diagnostic results on CXCR4-targeted PET, particularly considering detection, visualization, and prognostication. Patients and Methods: This study followed PRISMA-DTA. A systematic search was conducted on major medical literature databases up to March 1, 2024. The search strategy was designed to include CXCR4 PET studies in hematologic malignancies. A random-effects model combined sensitivity values derived from 2-by-2 contingency tables. Pooled means for SUV_max were computed. Analyses were performed by R software. Results: The initial search resulted in a total of 1428 studies. Ultimately, 18 were eligible for systematic review and meta-analytic calculations. Twelve studies (320 patients) included B-cell lymphoma. The pooled detection rate of CXCR4 PET was 99.4% (95% confidence interval [CI]: 88.3%–100%). Marginal zone lymphoma was investigated in 5 studies (209 patients), with a pooled sensitivity of 97.6% (95% CI: 79.7%–99.8%). In studies on central nervous system lymphoma, CXCR4 PET demonstrated 100% accuracy at both patient and lesion levels. Also, it demonstrated a significantly higher tumor-to-background ratio than ¹⁸F-FDG PET. For multiple myeloma, 5 studies (116 patients) showed a patient-level pooled sensitivity of 77.8% (95% CI: 64.4%–87.2%), whereas ¹⁸F-FDG PET had 65.0% (95% CI: 55.2%–73.7%). The pooled SUV_max for CXCR4 PET was 13.6 (95% CI: 9.3–17.8) versus 9.0 (95% CI: 6.3–11.7) for ¹⁸F-FDG PET. Additionally, CXCR4 PET-derived parameters were significant predictors of survival in multiple myeloma. Conclusions: CXCR4 PET can be a helpful imaging tool for evaluating hematologic malignancies, particularly in B-cell lymphoma and multiple myeloma patients. In specific clinical scenarios, it appears to be superior compared with the current standard-of-care imaging.

The potential of brain imaging has grown rapidly with new modalities, hybrid combinations of existing modalities, and novel metabolic tracers. F-florbetapir is an amyloid plaque-binding molecule labeled to F that allows positron imaging of the amyloid deposition in the brain. This protein deposition is known to be one of the features in Alzheimer disease and therefore can be of interest in the differential diagnosis of dementia. We present 2 cases combining the new hybrid imaging modality PET/MRI, which offers molecular and morphological information, with F-florbetapir in the differential diagnosis of dementia.