Abdominal pediatric cancer surveillance using serial computed tomography: evaluation of organ absorbed dose and effective dose

Validation and Optimization of Proximal Femurs Microstructure Analysis Using High Field and Ultra-High Field MRI

Trabecular bone could be assessed non-invasively using MRI. However, MRI does not yet provide resolutions lower than trabecular thickness and a comparative analysis between different MRI sequences at different field strengths and X-ray microtomography (μCT) is still missing. In this study, we compared bone microstructure parameters and bone mineral density (BMD) computed using various MRI approaches, i.e., turbo spin echo (TSE) and gradient recalled echo (GRE) images used at different magnetic fields, i.e., 7T and 3T. The corresponding parameters computed from μCT images and BMD derived from dual-energy X-ray absorptiometry (DXA) were used as the ground truth. The correlation between morphological parameters, BMD and fracture load assessed by mechanical compression tests was evaluated. Histomorphometric parameters showed a good agreement between 7T TSE and μCT, with 8% error for trabecular thickness with no significative statistical difference and a good intraclass correlation coefficient (ICC > 0.5) for all the extrapolated parameters. No correlation was found between DXA-BMD and all morphological parameters, except for trabecular interconnectivity (R2 > 0.69). Good correlation (p-value < 0.05) was found between failure load and trabecular interconnectivity (R2 > 0.79). These results suggest that MRI could be of interest for bone microstructure assessment. Moreover, the combination of morphological parameters and BMD could provide a more comprehensive view of bone quality.

Detection of Relapse by Tumor Markers Versus Imaging in Children and Adolescents With Nongerminomatous Malignant Germ Cell Tumors: A Report From the Children's Oncology Group

PURPOSE

To investigate relapse detection methods among children and adolescents with nongerminomatous malignant germ cell tumors (MGCTs) and to determine whether tumor markers alone might be sufficient for surveillance.

METHODS

We retrospectively reviewed all patients enrolled in a phase III, single-arm trial for low-risk and intermediate-risk MGCTs. The method used to detect relapse was assessed based on case report forms, tumor markers, imaging, and pathology reports. Relapses were classified into one of two categories on the basis of whether they were (1) detectable by tumor marker elevation or (2) not detectable by tumor markers.

RESULTS

A total of 302 patients were enrolled, and 284 patients had complete data for review. Seven patients had normal tumor markers at initial diagnosis, and none experienced a relapse. At a median follow-up of 5.3 years, 48 patients (16.9%) had experienced a relapse. After central review, 47 of 48 relapses (98%) were detected by tumor marker elevation. Of the 47 patients, 16 (33.3%) had abnormal tumor markers with normal/unknown imaging, 31 patients (64.6%) had abnormal tumor markers with abnormal imaging, and one patient (2.1%) had abnormal imaging with unknown marker levels at relapse.

CONCLUSION

Tumor marker elevation is a highly sensitive method of relapse surveillance, at least among children and adolescents with tumor marker elevation at initial diagnosis. Eliminating exposure to imaging with ionizing radiation may enhance the safety of relapse surveillance in patients treated for MGCT.