RASopathies for Radiologists.

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Neuroimaging of Neonatal Stroke: Venous Focus.

Perinatal venous infarcts are underrecognized clinically and at imaging. Neonates may be susceptible to venous infarcts because of hypercoagulable state, compressibility of the dural sinuses and superficial veins due to patent sutures, immature cerebral venous drainage pathways, and drastic physiologic changes of the brain circulation in the perinatal period. About 43% of cases of pediatric cerebral sinovenous thrombosis occur in the neonatal period. Venous infarcts can be recognized by ischemia or hemorrhage that does not respect an arterial territory. Knowledge of venous drainage pathways and territories can help radiologists recognize characteristic venous infarct patterns. Intraventricular hemorrhage in a term neonate with thalamocaudate hemorrhage should raise concern for internal cerebral vein thrombosis. A striato-hippocampal pattern of hemorrhage indicates basal vein of Rosenthal thrombosis. Choroid plexus hemorrhage may be due to obstruction of choroidal veins that drain the internal cerebral vein or basal vein of Rosenthal. Fan-shaped deep medullary venous congestion or thrombosis is due to impaired venous drainage into the subependymal veins, most commonly caused by germinal matrix hemorrhage in the premature infant and impeded flow in the deep venous system in the term infant. Subpial hemorrhage, an underrecognized hemorrhage stroke type, is often observed in the superficial temporal region, and its cause is probably multifactorial. The treatment of cerebral sinovenous thrombosis is anticoagulation, which should be considered even in the presence of intracranial hemorrhage. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Machine Learning-Based Multiparametric Magnetic Resonance Imaging Radiomics for Prediction of H3K27M Mutation in Midline Gliomas.

OBJECTIVE: H3K27M mutation in gliomas has prognostic implications. Previous magnetic resonance imaging (MRI) studies have reported variable rates of tumoral enhancement, necrotic changes, and peritumoral edema in H3K27M-mutant gliomas, with no distinguishing imaging features compared with wild-type gliomas. We aimed to construct an MRI machine learning (ML)-based radiomic model to predict H3K27M mutation in midline gliomas. METHODS: A total of 109 patients from 3 academic centers were included in this study. Fifty patients had H3K27M mutation and 59 were wild-type. Conventional MRI sequences (T1-weighted, T2-weighted, T2-fluid-attenuated inversion recovery, postcontrast T1-weighted, and apparent diffusion coefficient maps) were used for feature extraction. A total of 651 radiomic features per each sequence were extracted. Patients were randomly selected with a 7:3 ratio to create training (n = 76) and test (n = 33) data sets. An extreme gradient boosting algorithm (XGBoost) was used in ML-based model development. Performance of the model was assessed by area under the receiver operating characteristic curve. RESULTS: Pediatric patients accounted for a larger proportion of the study cohort (60 pediatric [55%] vs. 49 adult [45%] patients). XGBoost with additional feature selection had an area under the receiver operating characteristic curve of 0.791 and 0.737 in the training and test data sets, respectively. The model achieved accuracy, precision (positive predictive value), recall (sensitivity), and F1 (harmonic mean of precision and recall) measures of 72.7%, 76.5%, 72.2%, and 74.3%, respectively, in the test set. CONCLUSIONS: Our multi-institutional study suggests that ML-based radiomic analysis of multiparametric MRI can be a promising noninvasive technique to predict H3K27M mutation status in midline gliomas.

QR Codes: A Simple Tool for Engaging Radiology Audiences.

As the expectations of modern learners change, it is important for educators to adapt. Quick Response codes are an easy way to distribute web-based information to audiences. We familiarize the reader with Quick Response codes and demonstrate a few of the simple ways they can be incorporated into radiology lectures to increase audience engagement including reference dissemination, audience participation, surveys and quizzes.

CHEDDA syndrome: a case report and review of the literature for this newly described entity.

Congenital hypotonia, epilepsy, developmental delay, and digital anomalies (CHEDDA) is a recently identified neurodevelopmental syndrome which has only 8 reported cases to date since its existence was proposed in 2007. We report a case of CHEDDA syndrome identified in a newborn female with congenital anomalies including Pierre-Robin sequence, arthrogryposis, craniosynostosis, cleft palate, and cardiac abnormalities who subsequently developed epilepsy at 1 month of life. Diagnosis was identified by whole-exome sequencing identifying mutations in a conserved histidine-rich motif within the gene Atrophin-1. Radiologic findings of cerebral atrophy, hypoplasia of the cerebellum, and thinning of the corpus callosum were identified in this patient, consistent with other reported cases. Given the rarity of this condition, we report this case and its findings to increase awareness of CHEDDA syndrome as a possible underlying diagnosis for neonates who present with this constellation of symptoms and radiologic findings.

Imaging mimics of chronic recurrent multifocal osteomyelitis: avoiding pitfalls in a diagnosis of exclusion.

Chronic recurrent multifocal osteomyelitis (CRMO) is a pediatric autoinflammatory disorder that is characterized by multiple sterile inflammatory bone lesions with a relapsing and remitting course. CRMO belongs to the autoinflammatory family of rheumatologic disorders based on absence of significant titers of autoantibodies and autoreactive T-lymphocytes. In absence of pathognomonic clinical, radiographic or pathological features, diagnosis can be challenging. CRMO shares imaging features with other diseases. It is important for radiologists to be able to differentiate other diseases from CRMO because prognosis varies from completely benign to frankly malignant. In this article we first present the clinical and imaging features of CRMO to help readers gain an understanding of the disease process, then discuss our imaging approach to CRMO and review other disease processes that sometimes share similar imaging findings to CRMO and review differentiating features to help avoid misdiagnoses.

Conventional Medical Education and the History of Simulation in Radiology.

Simulation is a promising method for improving clinician performance, enhancing team training, increasing patient safety, and preventing errors. Training scenarios to enrich medical student and resident education, and apply toward competency assessment, recertification, and credentialing are important applications of simulation in radiology. This review will describe simulation training for procedural skills, interpretive and noninterpretive skills, team-based training and crisis management, professionalism and communication skills, as well as hybrid and in situ applications of simulation training. A brief overview of current simulation equipment and software and the barriers and strategies for implementation are described. Finally, methods of measuring competency and assessment are described, so that the interested reader can successfully implement simulation training into their practice.

Pulmonary embolism teaching file: a simple pilot study for rapidly increasing pulmonary embolism recognition among new residents using interactive cross-sectional imaging.

RATIONALE AND OBJECTIVES: Chest radiographs can be demanding, making this an area of focus during most first-year resident chest rotations. This often comes at a cost of cross-sectional imaging, and new residents are often not initially comfortable with reading chest computed tomographic angiograms (CTAs) for pulmonary embolisms (PEs). We created a teaching file of CTAs to improve the detection of PEs. MATERIALS AND METHODS: For initial testing, we used videos of 25 cases, which played for 90 seconds (to allow multiple passes) to residents with and without call experience. The presence and location of PEs and the readers' confidence scores were recorded. After initial testing, first-year residents without call experience were given 20 separate known positive CTA videos to scroll through on their own. The goal of this was to allow for individual review and development of individual search strategies. A second testing was done with all levels of residents with the same initial 25 cases, re-randomized to evaluate for improvement. RESULTS: Initially, first-year residents without call experience identified an average of 14.7 of 18 examinations positive for PEs (versus 15.8 for more senior residents; P < .04). After reviewing the 20 known positive cases, the first-year residents improved, averaging 16.6 (versus 14.7 earlier; P < .01). CONCLUSIONS: We created a fast, simple way to expose novice residents to CTA examinations and increase their accuracy in identifying PEs. After using a teaching file, the ability to recognize PEs improved significantly, and scores were no longer significantly different from those of residents with call experience.