Current and Emerging Roles of Whole-Body MRI in Evaluation of Pediatric Cancer Patients.

Imaging is fundamental to diagnosis and management of pediatric patients with cancer and cancer predisposition syndromes (CPSs). Whole-body MRI has emerged as a versatile tool for pediatric oncologic imaging, with the potential to spare children from ionizing radiation imparted by conventional modalities such as CT and PET. Whole-body MRI also enables simultaneous high-resolution local-regional staging and wide field-of-view distant staging in the same imaging session, with superior evaluation of the brain, spine, liver, and marrow. Recent technical advances have reduced imaging times and enhanced image quality, with continued advances on the near horizon. Pulse sequences such as whole-body diffusion-weighted imaging have also broadened the range of diagnostic information obtainable. In addition, increasing identification of children with CPSs has compelled efforts to establish surveillance imaging strategies for affected individuals, with whole-body MRI playing a pivotal role in screening algorithms for several CPSs. In light of these emerging trends, a working knowledge of oncologic whole-body MRI applications and evolving CPS surveillance algorithms is vital to providers who participate in the care of pediatric patients affected by or predisposed to cancer. Recognizing both the strengths and limitations of whole-body MRI not only enables more thoughtful implementation but also improves the accuracy of image interpretation. ©RSNA, 2019 See discussion on this article by Khanna .

Patient Outcomes and Predictors of Success After Revision Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Patient outcomes and predictors of success after revision anterior cruciate ligament (ACL) reconstruction are currently limited in the literature. Existing studies either have a small study size or are difficult to interpret because of the multiple surgeons involved in the care of the study sample. PURPOSE: To determine patient outcomes and predictors of success or failure after a single-stage revision ACL reconstruction by a single fellowship-trained senior surgeon at a single institution. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 78 patients who underwent revision ACL reconstruction by a single surgeon from 2010 to 2014 were contacted and available for follow-up. The mean time from revision procedure to follow-up was 52 months. Those patients who were able to participate in the study sent in a completed Tegner activity level scale, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, and IKDC Current Health Assessment Form. The patients' medical records were also thoroughly reviewed. RESULTS: Five patients had subsequent failure after revision surgery. The median Tegner score was 6 at follow-up, and the mean subjective IKDC score was 72.5. There was no statistically significant difference in outcome scores when comparing revision graft type, body mass index, sex, need for bone grafting, and time from failure to revision. Patients with failures after primary ACL reconstruction secondary to a traumatic event were found to have statistically significantly higher IKDC scores (mean, 76.6) after revision when compared with nontraumatic failures (mean, 67.1), even when controlling for confounders (P < .017). CONCLUSION: Revision ACL reconstruction is effective in improving patient activity levels and satisfaction. However, the subjective IKDC results are quite variable and likely based on multiple factors. Patients with traumatic injuries contributing to graft failure after primary ACL reconstruction had a statistically significantly, although not clinically significant, higher IKDC score after revision surgery compared with nontraumatic failures. These data may be useful when counseling a patient on whether to pursue revision ACL reconstruction surgery.

Superresolution STED microscopy reveals differential localization in primary cilia.

The primary cilium is an organelle that serves as a signaling center of the cell and is involved in the cAMP, Wnt, and hedgehog signaling pathways. Adenylyl cyclase type III (ACIII) is enriched in primary cilia and acts as a marker that is involved in cAMP signaling, while also playing an important role in regulating ciliogenesis and sensory functions. Ciliary function relies on the transportation of molecules between the primary cilium and the cell, which is facilitated by intraflagellar transport (IFT). The detailed localization and interactions of these important proteins remain unclear due to the limited resolution of conventional microscopy. We conducted superresolution imaging of immunostained ACIII and IFT88 in human fibroblasts using stimulated emission depletion (STED) microscopy. Instead of a homogeneous distribution along a primary cilium, our STED images revealed that ACIII formed a periodic punctate pattern with a roughly equal spacing between groups of puncta. Superresolution imaging of IFT88, an important protein of the IFT complexes, demonstrated two novel distinct distribution patterns at the basal end: a triangle of three puncta with similar fluorescence intensities, and a Y-shaped configuration of a bright punctum connected to two branches. We also performed STED imaging of IFT88 in mouse inner medullary collecting duct cells and mouse embryonic fibroblasts. The similar three-puncta and Y-shape patterns were observed in these cells, suggesting that these distribution patterns are common among primary cilia of different cell types. Our results demonstrate the ability of superresolution STED microscopy to reveal novel structural characteristics in primary cilia.