Neural basis of interindividual variability in social perception in typically developing children and adolescents using diffusion tensor imaging.

Humans show great interindividual variability in the degree they engage in social relationship. The neural basis of this variability is still poorly understood, particularly in children. In this study, we aimed to investigate the neural basis of interindividual variability in the first step of social behavior, that is social perception, in typically developing children. For that purpose, we first used eye-tracking to objectively measure eye-gaze processing during passive visualization of social movie clips in 24 children and adolescents (10.5 ± 2.9 y). Secondly, we correlated eye-tracking data with measures of fractional anisotropy, an index of white matter microstructure, obtained using diffusion tensor imaging MRI. The results showed a large interindividual variability in the number of fixations to the eyes of characters during visualization of social scenes. In addition, whole-brain analysis showed a significant positive correlation between FA and number of fixations to the eyes,mainly in the temporal part of the superior longitudinal fasciculi bilaterally, adjacent to the posterior superior temporal cortex. Our results indicate the existence of a neural signature associated with the interindividual variability in social perception in children, contributing for better understanding the neural basis of typical and atypical development of a broader social expertise.

Evaluation of the Implementation of the Response Assessment in Neuro-Oncology Criteria in the HERBY Trial of Pediatric Patients with Newly Diagnosed High-Grade Gliomas.

BACKGROUND AND PURPOSE: HERBY was a Phase II multicenter trial setup to establish the efficacy and safety of adding bevacizumab to radiation therapy and temozolomide in pediatric patients with newly diagnosed non-brain stem high-grade gliomas. This study evaluates the implementation of the radiologic aspects of HERBY. MATERIALS AND METHODS: We analyzed multimodal imaging compliance rates and scan quality for participating sites, adjudication rates and reading times for the central review process, the influence of different Response Assessment in Neuro-Oncology criteria in the final response, the incidence of pseudoprogression, and the benefit of incorporating multimodal imaging into the decision process. RESULTS: Multimodal imaging compliance rates were the following: diffusion, 82%; perfusion, 60%; and spectroscopy, 48%. Neuroradiologists' responses differed for 50% of scans, requiring adjudication, with a total average reading time per patient of approximately 3 hours. Pseudoprogression occurred in 10/116 (9%) cases, 8 in the radiation therapy/temozolomide arm and 2 in the bevacizumab arm (P < .01). Increased target enhancing lesion diameter was a reason for progression in 8/86 cases (9.3%) but never the only radiologic or clinical reason. Event-free survival was predicted earlier in 5/86 (5.8%) patients by multimodal imaging (diffusion, n = 4; perfusion, n = 1). CONCLUSIONS: The addition of multimodal imaging to the response criteria modified the assessment in a small number of cases, determining progression earlier than structural imaging alone. Increased target lesion diameter, accounting for a large proportion of reading time, was never the only reason to designate disease progression.

Diffuse intrinsic pontine gliomas (DIPG) at recurrence: is there a window to test new therapies in some patients?

Children with diffuse intrinsic pontine glioma (DIPG) need new and more efficient treatments. They can be developed at relapse or at diagnosis, but therefore they must be combined with radiotherapy. Survival of children after recurrence and its predictors were studied to inform the possibility to design early phase clinical trials for DIPG at this stage. Among 142 DIPG patients treated between 1998 and 2014, 114 had biopsy-proven DIPG with histone H3 status available for 83. We defined as long survivors' patients who survived more than 3 months after relapse which corresponds to the minimal life expectancy requested for phase I/II trials. Factors influencing post-relapse survival were accordingly compared between short and long-term survivors after relapse. Fifty-seven percent of patients were considered long survivors and 70% of them had a Lansky Play Scale (LPS) above 50% at relapse. Patients who became steroids-independent after initial treatment for at least 2 months had better survival after relapse (3.7 versus 2.6 months, p = 0.001). LPS above 50% at relapse was correlated with better survival after relapse (3.8 versus 1.8 months, p < 0.001). Patients with H3.1 mutation survived longer after relapse (4.9 versus 2.7 months, p = 0.007). Patients who received a second radiotherapy at the time of relapse had an improved survival (7.5 versus 4 months, p = 0.001). In the two-way ANOVA analysis, steroid-independence and LPS predicted survival best and the type of histone H3 (H3.1 or H3.3) mutated did not improve prediction. Survival of many DIPG patients after relapse over 3 months would make possible to propose specific trials for this condition. Steroid-independence, H3 mutation status and LPS should be considered to predict eligibility.

Response Assessment in Pediatric Neuro-Oncology: Implementation and Expansion of the RANO Criteria in a Randomized Phase II Trial of Pediatric Patients with Newly Diagnosed High-Grade Gliomas.

Determination of tumor response to treatment in neuro-oncology is challenging, particularly when antiangiogenic agents are considered. Nontumoral factors (eg, blood-brain barrier disruption, edema, and necrosis) can alter contrast enhancement independent of true tumor response/progression. Furthermore, gliomas are often infiltrative, with nonenhancing components. In adults, the Response Assessment in Neuro-Oncology (RANO) criteria attempted to address these issues. No such guidelines exist yet for children. The ongoing randomized phase II trial, A Study of Avastin (bevacizumab) in Combination With Temolozomide (TMZ) and Radiotherapy in Paediatric and Adolescent Patients With High-Grade Glioma (HERBY), will establish the efficacy and safety of the antiangiogenic agent bevacizumab for the first-line treatment of newly diagnosed high-grade glioma in children (n = 121 patients, enrollment complete). The primary end point is event-free survival (tumor progression/recurrence by central review, second primary malignancy, or death). Determination of progression or response is based on predefined clinical and radiographic criteria, modeled on the RANO criteria and supported by expert pseudoprogression review and the use of standardized imaging protocols. The HERBY trial will also compare conventional MR imaging (T1-weighted and T2/fluid-attenuated inversion recovery sequences) with conventional MR imaging plus diffusion/perfusion imaging for response assessment. It is anticipated that HERBY will provide new insights into antiangiogenic-treated pediatric brain tumors. HERBY will also investigate the practicality of obtaining adequate quality diffusion/perfusion scans in a trial setting, and the feasibility of implementing standard imaging protocols across multiple sites. To date, 61/73 (83.6%) patients with available data have completed diffusion-weighted imaging (uptake of other nonconventional techniques has been limited). Harmonization of imaging protocols and techniques may improve the robustness of pediatric neuro-oncology studies and aid future trial comparability.

Cerebral Blood Flow Improvement after Indirect Revascularization for Pediatric Moyamoya Disease: A Statistical Analysis of Arterial Spin-Labeling MRI.

BACKGROUND AND PURPOSE: The severity of Moyamoya disease is generally scaled with conventional angiography and nuclear medicine. Arterial spin-labeling MR imaging is now acknowledged for the noninvasive quantification of cerebral blood flow. This study aimed to analyze CBF modifications with statistical parametric mapping of arterial spin-labeling MR imaging in children undergoing an operation for Moyamoya disease. MATERIALS AND METHODS: We included 15 children treated by indirect cerebral revascularization with multiple burr-holes between 2011 and 2013. Arterial spin-labeling MR imaging and T1 sequences were then analyzed under SPM8, according to the general linear model, before and after the operation (3 and 12 months). Voxel-based analysis was performed at the group level, comparing all diseased hemispheres with all normal hemispheres and, at the individual level, comparing each patient with a control group. RESULTS: Group analysis showed statistically significant preoperative hypoperfusion in the MCA territory in the Moyamoya hemispheres and a significant increase of cerebral perfusion in the same territory after revascularization (P < .05 family-wise error-corrected). Before the operation, individual analysis showed significant hypoperfusion for each patient co-localized with the angiographic defect on DSA. All except 1 patient had improvement of CBF after revascularization, correlated with their clinical status. CONCLUSIONS: SPM analysis of arterial spin-labeling MR imaging offers a noninvasive evaluation of preoperative cerebral hemodynamic impairment and an objective assessment of postoperative improvement in children with Moyamoya disease.

Choroid Plexus Neoplasms: Toward a Distinction between Carcinoma and Papilloma Using Arterial Spin-Labeling.

Pediatric choroid plexus papillomas and carcinomas are highly vascularized neoplasms, which are difficult to distinguish with conventional imaging. We aimed to analyze the diagnostic accuracy of PWI, by using both pseudocontinuous arterial spin-labeling and DSC-PWI. We reviewed the PWI of 13 children with choroid plexus neoplasms (7 papillomas and 6 carcinomas). We quantified CBF, relative CBF, and relative CBV in each lesion and compared papillomas and carcinomas. Relative CBF values by using arterial spin-labeling were significantly higher for carcinomas (P = .028). The median value of relative CBF was 1.7 (range, 1.4-1.9) for carcinomas and 0.4 (range, 0.3-0.6) for papillomas. The CBF median value was 115 mL/min/100 g (range, 90-140 mL/min/100 g) for carcinomas and 41 mL/min/100 g (range, 10-73 mL/min/100 g) for papillomas (P = .056). Measures with DSC-PWI were more variable and not significantly different (P = .393). Arterial spin-labeling is a promising technique to differentiate choroid plexus carcinomas and papillomas.

CT-guided biopsies in lung infections in patients with haematological malignancies.

CT-guided transparietal lung biopsy in imaging makes it possible to find the pathogenic agent in half of all fungal infections and most bacterial infections (sensitivity=55%, specificity=100%). Performance is decreased in consolidations (50% of infections) compared to masses. Complications, pneumothorax, alveolar bleeding and hemoptysis are generally benign and rarely (<5%) require specific treatment. On the other hand, the diagnostic performance increases significantly with the calibre of 18G co-axial systems compared to 20G. The risk is not related to the number of samples or platelet levels.

[CT and MRI imaging in tumoral angiogenesis]. / Imagerie TDM et IRM de l'angiogenèse tumorale.

Angiogenesis is the process of activating dormant endothelial cells to form new vessels, after stimulation and it is essential in tumor growth. In many types of cancer, angiogenesis results from the activation of oncogenes that stimulate the production of Vascular Endothelial Growth Factor (VEGF). However, these newly formed vessels have a great number of abnormalities: increased density of fragile and hyper-permeable microvessels, arterial-venous shunts, caliber abnormalities and flow instabilities susceptible to flow direction inversion according to interstitial pressure. Anti-angiogenic treatments inhibit VEGF activity, perceived as structural and functional normalization of the microvascular pattern, such as reduced density of microvessels and restored morphology of the remaining ones. Conventional imaging techniques are not sensible to these changes, at best they show tumor size stabilization, hence the need of new techniques. Microvascularization imaging can be achieved by detecting functional disturbances to blood flow and not by showing the microvasculature per se. These techniques are based in quantifying the enhancement in tumor due to the passage of contrast agent after injection or protons labeled by a magnetic field. Through these measurements, one can derive interstitial and blood volumes as well as the tissue perfusion and capillary wall permeability. Microvascular imaging has greatly benefited from the improvements seen in CT and MRI equipment allowing large volume coverage with high spatial and temporal resolutions as from the evolutions in the methods to calculate, present and compare maps of the microcirculation and it's heterogeneity. However, software to analyze microvascularization are still rare, limiting the technique's application and validation in large scale. Nevertheless, imaging of the microcirculation is useful throughout the care of the oncological patient: it can reinforce the suspicious nature of a lesion, suggest anti-angiogenic treatment efficacy in hypervascular lesions, and show early treatment response before morphological changes as in RECIST criteria.