Leigh syndrome by definition is (1) a neurodegenerative disease with variable symptoms, (2) caused by mitochondrial dysfunction from a hereditary genetic defect and (3) accompanied by bilateral central nervous system lesions. A genetic etiology is confirmed in approximately 50% of patients, with more than 60 identified mutations in the nuclear and mitochondrial genomes. Here we review the clinical features and imaging studies of Leigh syndrome and describe the neuroimaging findings in a cohort of 17 children with genetically confirmed Leigh syndrome. MR findings include lesions in the brainstem in 9 children (53%), basal ganglia in 13 (76%), thalami in 4 (24%) and dentate nuclei in 2 (12%), and global atrophy in 2 (12%). The brainstem lesions were most frequent in the midbrain and medulla oblongata. With follow-up an increased number of lesions from baseline was observed in 7 of 13 children, evolution of the initial lesion was seen in 6, and complete regression of the lesions was seen in 3. No cerebral white matter lesions were found in any of the 17 children. In concordance with the literature, we found that Leigh syndrome follows a similar pattern of bilateral, symmetrical basal ganglia or brainstem changes. Lesions in Leigh syndrome evolve over time and a lack of visible lesions does not exclude the diagnosis. Reversibility of lesions is seen in some patients, making the continued search for treatment and prevention a priority for clinicians and researchers.

Approximately one-third of all cervical spine injuries involve the craniocervical junction (CCJ). Composed of the occiput and the first two cervical vertebrae, this important anatomic landmark, in conjunction with an intricate ligamentous complex, is essential to maintaining the stability of the cervical spine. The atlantoaxial joint is the most mobile portion of the spine, predominantly relying on the ligamentous framework for stability at that level. As acute onsite management of trauma patients continues to improve, CCJ injuries, which often lead to death onsite where the injury occurred, are increasingly being encountered in the emergency department. Understanding the anatomy of the CCJ is crucial in properly evaluating the cervical spine, allowing the radiologist to assess its stability in the trauma setting. The imaging findings of important CCJ injuries, such as atlanto-occipital dissociation, occipital condyle fractures, atlas fractures with transverse ligament rupture, atlantoaxial distraction, and traumatic rotatory subluxation, are important to recognize in the acute setting, often dictating patient management. Thin-section multidetector computed tomography with sagittal and coronal reformats is the study of choice in evaluating the extent of injury, allowing the radiologist to thoroughly evaluate the stability of the cervical spine. Furthermore, magnetic resonance (MR) imaging is increasingly being used to evaluate the spinal soft tissues and ligaments, and to identify associated spinal cord injury, if present. MR imaging is also indicated in patients whose neurologic status cannot be evaluated within 48 hours of injury. .

The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies.

Objective Our objective is to document the imaging appearance in the intracranial compartment at the time of the infants' first postnatal brain MR imaging after fetal repair for spinal dysraphisms. Methods Twenty-nine patients were evaluated on fetal and postnatal magnetic resonance imaging for a series of features of Chiari II malformation. Results Of the 29 infants, 55% had resolution of tonsillar ectopia, and 62% showed a dorsal outpouching of the near the foramen magnum on postnatal magnetic resonance imaging. The majority had persistence of Chiari II features including: prominent massa intermedia (93%), tectal beaking (93%), towering cerebellum (55%), flattening of the fourth ventricle (90%), hypoplastic tentorium (97%), and tonsillar hypoplasia (59%). Conclusions Normally positioned or minimally descended, oftentimes hypoplastic tonsils in the presence of a posterior fossa configuration typical of Chiari II, was the most common presentation. An additional documented feature was an outpouching of the dorsal thecal sac between the opisthion and the posterior arch of C1.

Hepatic encephalopathy and hyperammonemia are common in the setting of liver disease and have been associated with both generalized and focal neurological deficits. We report a case of hepatic encephalopathy with transaminitis in the setting of hyperammonemia clinically mimicking acute dominant middle cerebral artery (MCA) syndrome. A 59-year-old right-handed woman had new-onset expressive aphasia, left gaze deviation, and right hemiparesis consistent with MCA stroke. Her symptoms began 12 h after transarterial chemoembolization, a procedure to embolize blood supply and provide cytotoxic agents to a hepatocellular carcinoma tumor. Thrombocytopenia and age-indeterminate hypodensities on brain CT precluded intravenous thrombolytic administration. MRI revealed predominantly dominant hemisphere subcortical restricted diffusion with no cortical involvement. Due to a mismatch between the MRI findings and the neurological symptoms, she underwent digital subtraction cerebral angiography to assess candidacy for intra-arterial thrombectomy, which revealed completely patent MCAs with intact filling of the distal branches. Liver enzymes and ammonia were elevated. The patient was treated with lactulose and intravenous fluids. After normalization of liver enzymes, the patient’s neurological deficits resolved. Reversal of this patient’s focal symptoms with medical management could potentially be explained by the recovery of blood flow-metabolic demand mismatch caused by worsening liver dysfunction and hyperammonemia. As acute stroke therapies and interventions increase in utility for large artery acute ischemic stroke, it is vital to recognize hepatic encephalopathy and liver failure as part of the differential diagnosis for patients presenting with MCA syndrome.

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The aim of this study is to evaluate whether we could develop a machine learning method to distinguish models of cerebrospinal fluid shunt valves (CSF-SVs) from their appearance in clinical X-rays. This is an essential component of an automatic MRI safety system based on X-ray imaging. To this end, a retrospective observational study using 416 skull X-rays from unique subjects retrieved from a clinical PACS system was performed. Each image included a CSF-SV representing the most common brands of programmable shunt valves currently used in US which were split into five different classes. We compared four machine learning pipelines: two based on engineered image features (Local Binary Patterns and Histogram of Oriented Gradients) and two based on features learned by a deep convolutional neural network architecture. Performance is evaluated using accuracy, precision, recall and f1-score. Confidence intervals are computed with non-parametric bootstrap procedures. Our best performing method identified the valve type correctly 96% [CI 94–98%] of the time (CI: confidence intervals, precision 0.96, recall 0.96, f1-score 0.96), tested using a stratified cross-validation approach to avoid chances of overfitting. The machine learning pipelines based on deep convolutional neural networks showed significantly better performance than the ones based on engineered image features (mean accuracy 95–96% vs. 56–64%). This study shows the feasibility of automatically distinguishing CSF-SVs using clinical X-rays and deep convolutional neural networks. This finding is the first step towards an automatic MRI safety system for implantable devices which could decrease the number of patients that experience denials or delays of their MRI examinations.

Objective For research and risk factor analysis, a reproducible method quantifying atherosclerosis is necessary. Our aim was to develop a computed tomography (CT) angiography grading system to quantify atherosclerotic disease of the head and neck. Methods Institutional review board–approved, retrospective analysis was performed on 152 patients who underwent head/neck CT angiography. A grading scale was designed to calculate plaque burden at multiple sites with the sum referred to as atherosclerosis score. Three radiologists calculated scores with an overlap of cases to calculate the intraclass correlation coefficient. Results Without any prior training, the intraclass correlation coefficient between readers was considered fair. After a short tutorial, intraclass correlation coefficient was recalculated using separate patients, showing excellent correlation. Statistically significant positive correlation was found between atherosclerosis scale and age, hyperlipidemia, hypertension, and diabetes, but no correlation with sex or smoking status. Conclusions A simple, visual grading scale for atherosclerosis in head/neck CT angiography was used to standardize reporting and better characterize a patient's risk of stroke.