Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

Objectives: The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Methods: Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Results: Mean T2 of the AMIC-RT and cartilage were 43.1ms and 39.1ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76μm2/ms) was significantly higher compared to normal cartilage (1.46μm2/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28months (p = 0.027). Conclusions: Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. Key Points : • MRI is used to assess morphology of the repair tissue during follow-up. • Quantitative MRI allows an estimation of biochemical properties of the repair tissue. • Differences between repair tissue and cartilage were more significant with dwDESS than T2 mapping

Longitudinal Assessment of Enhancing Foci of Abnormal Signal Intensity in Neurofibromatosis Type1

BACKGROUND AND PURPOSE Patients with neurofibromatosis 1 are at increased risk of developing brain tumors, and differentiation from contrast-enhancing foci of abnormal signal intensity can be challenging. We aimed to longitudinally characterize rare, enhancing foci of abnormal signal intensity based on location and demographics. MATERIALS AND METHODS A total of 109 MR imaging datasets from 19 consecutive patients (7 male; mean age, 8.6 years; range, 2.3-16.8 years) with neurofibromatosis 1 and a total of 23 contrast-enhancing parenchymal lesions initially classified as foci of abnormal signal intensity were included. The mean follow-up period was 6.5 years (range, 1-13.8 years). Enhancing foci of abnormal signal intensity were followed up with respect to presence, location, and volume. Linear regression analysis was performed. RESULTS Location, mean peak volume, and decrease in enhancing volume over time of the 23 lesions were as follows: 10 splenium of the corpus callosum (295 mm$^{3}$, 5 decreasing, 3 completely resolving, 2 surgical intervention for change in imaging appearance later confirmed to be gangliocytoma and astrocytoma WHO II), 1 body of the corpus callosum (44 mm$^{3}$, decreasing), 2 frontal lobe white matter (32 mm$^{3}$, 1 completely resolving), 3 globus pallidus (50 mm$^{3}$, all completely resolving), 6 cerebellum (206 mm$^{3}$, 3 decreasing, 1 completely resolving), and 1 midbrain (34 mm$^{3}$). On average, splenium lesions began to decrease in size at 12.2 years, posterior fossa lesions at 17.1 years, and other locations at 9.4 years of age. CONCLUSIONS Albeit very rare, contrast-enhancing lesions in patients with neurofibromatosis 1 may regress over time. Follow-up MR imaging aids in ascertaining regression. The development of atypical features should prompt further evaluation for underlying tumors

Radiomics of Pediatric Low-Grade Gliomas: Toward a Pretherapeutic Differentiation of BRAF-Mutated and BRAF-Fused Tumors

BACKGROUND AND PURPOSE B-Raf proto-oncogene, serine/threonine kinase (BRAF) status has important implications for prognosis and therapy of pediatric low-grade gliomas. Currently, BRAF status classification relies on biopsy. Our aim was to train and validate a radiomics approach to predict BRAF fusion and BRAF V600E mutation. MATERIALS AND METHODS In this bi-institutional retrospective study, FLAIR MR imaging datasets of 115 pediatric patients with low-grade gliomas from 2 children's hospitals acquired between January 2009 and January 2016 were included and analyzed. Radiomics features were extracted from tumor segmentations, and the predictive model was tested using independent training and testing datasets, with all available tumor types. The model was selected on the basis of a grid search on the number of trees, opting for the best split for a random forest. We used the area under the receiver operating characteristic curve to evaluate model performance. RESULTS The training cohort consisted of 94 pediatric patients with low-grade gliomas (mean age, 9.4 years; 45 boys), and the external validation cohort comprised 21 pediatric patients with low-grade gliomas (mean age, 8.37 years; 12 boys). A 4-fold cross-validation scheme predicted BRAF status with an area under the curve of 0.75 (SD, 0.12) (95% confidence interval, 0.62-0.89) on the internal validation cohort. By means of the optimal hyperparameters determined by 4-fold cross-validation, the area under the curve for the external validation was 0.85. Age and tumor location were significant predictors of BRAF status (P values = .04 and <.001, respectively). Sex was not a significant predictor (P value = .96). CONCLUSIONS Radiomics-based prediction of BRAF status in pediatric low-grade gliomas appears feasible in this bi-institutional exploratory study

The SFCNS Young Clinical Neuroscientists Network Cultivating ties across clinical neuroscience disciplines

Interdisciplinary cooperation and interaction have grown extremely important and will soon become indispensable in clinical neuroscience. The constantly increasing degree of specialization may further compartmentalize the different clinical neuroscience disciplines, potentially altering a unified identity in the field. In 2016, the Swiss Federation of Clinical Neuro-Societies (SFCNS) encouraged the creation of the Young Clinical Neuroscientists (YouCliN) Network bringing together juniors from all specialties united in the SFCNS – that is, biological psychiatry, neurology, neuropathology, neuropediatrics, neuropsychology, neuroradiology and neurosurgery. The main YouCliN mission is to cultivate an interdisciplinary spirit among clinical neuroscience trainees – in order for them to be prepared to face future challenges in a shoulder-to-shoulder manner. Moreover, the YouCliN represents junior interests in current issues of Swiss clinical neuroscience and contributes to shaping interdisciplinary training and courses. Transversality, better integration between fundamental and clinical neuroscience as well as between psychiatry and clinical neuroscience, and equal gender opportunities are further important topics and fields of action. In this article, the YouCliN Steering Committee presents the Network, the disciplines’ specific concerns and hopes, and positions itself with respect to future challenges for clinical neuroscience