Schlein, Alexandra

The diagnosis, treatment, and management of gynecologic malignancies benefit from both positron emission tomography/computed tomography (PET/CT) and MRI. PET/CT provides important information on the local extent of disease as well as diffuse metastatic involvement. MRI offers soft tissue delineation and loco-regional disease involvement. The combination of these two technologies is key in diagnosis, treatment planning, and evaluating treatment response in gynecological malignancies. This review aims to assess the performance of PET/MRI in gynecologic cancer patients and outlines the technical challenges and clinical advantages of PET/MR systems when specifically applied to gynecologic malignancies.

BackgroundMagnetic resonance elastography (MRE) can determine the presence and stage of liver fibrosis. Data on normative MRE values, while reported in adults, are limited in children.PurposeTo determine the distribution of MRE‐measured liver stiffness in children without liver disease.Study TypeProspective, observational.PopulationEighty‐one healthy children (mean 12.6 ± 2.6 years, range 8–17 years).Field Strength/Sequence3.0T Signa HDxt, General Electric MR Scanner; 2D GRE MRE sequence.AssessmentHistory, examination, laboratory evaluation, and (MR) exams (proton density fat fraction, PDFF, and MRE) were performed. MR elastograms were analyzed manually at two reading centers and compared with each other for agreement and with published values in healthy adults and thresholds for fibrosis in adult and pediatric patients.Statistical TestsDescriptive statistics, Bland–Altman analysis, t‐test to compare hepatic stiffness values with reference standards.ResultsStiffness values obtained at both reading centers were similar, without significant bias (P = 0.362) and with excellent correlation (intraclass correlation coefficient [ICC] = 0.782). Mean hepatic stiffness value for the study population was 2.45 ± 0.35 kPa (95th percentile 3.19 kPa), which was significantly higher than reported values for healthy adult subjects (2.10 ± 0.23 kPa, P < 0.001). In all, 74–85% of subjects had stiffness measurements suggestive of no fibrosis.Data ConclusionMean liver stiffness measured with MRE in this cohort was significantly higher than that reported in healthy adults. Despite rigorous screening, some healthy children had stiffness measurements suggestive of liver fibrosis using current published thresholds. Although MRE has the potential to provide noninvasive assessment in patients with suspected hepatic disease, further refinement of this technology will help advance its use as a diagnostic tool for evidence of fibrosis in pediatric populations.Level of Evidence: 1Technical Efficacy: 5J. Magn. Reson. Imaging 2020;51:919–927.

Magnetic resonance elastography (MRE) is a promising technique for noninvasive assessment of fibrosis, a major determinant of outcome in nonalcoholic fatty liver disease (NAFLD). However, data in children are limited. The purpose of this study was to determine the accuracy of MRE for the detection of fibrosis and advanced fibrosis in children with NAFLD and to assess agreement between manual and novel automated reading methods. We performed a prospective, multicenter study of two‐dimensional (2D) MRE in children with NAFLD. MR elastograms were analyzed manually at two reading centers, and using a new automated technique. Analysis using each approach was done independently. Correlations were determined between MRE analysis methods and fibrosis stage. Thresholds for classifying the presence of fibrosis and of advanced fibrosis were computed and cross‐validated. In 90 children with a mean age of 13.1 ± 2.4 years, median hepatic stiffness was 2.35 kPa. Stiffness values derived by each reading center were strongly correlated with each other (r = 0.83). All three analyses were significantly correlated with fibrosis stage (center 1, ρ = 0.53; center 2, ρ = 0.55; and automated analysis, ρ = 0.52; P < 0.001). Overall cross‐validated accuracy for detecting any fibrosis was 72.2% for all methods (95% confidence interval [CI], 61.8%‐81.1%). Overall cross‐validated accuracy for assessing advanced fibrosis was 88.9% (95% CI, 80.5%‐94.5%) for center 1, 90.0% (95% CI, 81.9%‐95.3%) for center 2, and 86.7% (95% CI, 77.9%‐92.9%) for automated analysis. Conclusion : 2D MRE can estimate hepatic stiffness in children with NAFLD. Further refinement and validation of automated analysis techniques will be an important step in standardizing MRE. How to best integrate MRE into clinical protocols for the assessment of NAFLD in children will require prospective evaluation. (H epatology 2017;66:1474–1485)