Neuromyelitis Optica Spectrum Disorders and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease.

For over two centuries, clinicians have been aware of various conditions affecting white matter which had come to be grouped under the umbrella term multiple sclerosis. Within the last 20 years, specific scientific advances have occurred leading to more accurate diagnosis and differentiation of several of these conditions including, neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody disease. This new understanding has been coupled with advances in disease-modifying therapies which must be accurately applied for maximum safety and efficacy.

Toxic and Drug-Related White Matter Diseases of the Brain and Spine.

Toxic leukoencephalopathy and myelopathy are common neurologic complications of a wide range of chemotherapeutic and substance abuse agents. During the last decade, there has been a significant change in the profile of white matter toxins, primarily driven by the development and usage of new chemotherapeutic and immunotherapeutic agents and by the continuous increase in illicit drug abuse with contaminants. Neuroimaging in the form of MR imaging forms the cornerstone in the diagnosis of these entities, many of which are reversible and amenable to rapid correction. Chronic white matter changes are also seen with these toxins with gradually progressive clinicoradiological findings.

Glioblastoma with a primitive neuroectodermal component: two cases with implications for glioblastoma cell-of-origin.

BACKGROUND: Glioblastoma (GBM) is the most common primary brain malignancy, but much remains unknown about the histogenesis of these tumors. In the great majority of cases, GBM is a purely glial tumor but in rare cases the classic-appearing high-grade glioma component is admixed with regions of small round blue cells with neuronal immunophenotype, and these tumors have been defined in the WHO 2016 Classification as "glioblastoma with a primitive neuronal component." METHODS: In this paper, we present two cases of GBM-PNC with highly divergent clinical courses, and review current theories for the GBM cell-of-origin. RESULTS AND CONCLUSIONS: GBM-PNC likely arises from a cell type competent to give rise to glial or neuronal lineages. The thesis that GBM recapitulates to some extent normal neurodevelopmental cellular pathways is supported by molecular and clinical features of our two cases of GBM-PNC, but more work is needed to determine which cellular precursor gives rise to specific cases of GBM. GBM-PNC may have a dramatically altered clinical course compared to standard GBM and may benefit from specific lines of treatment.

Iodinated Contrast Extravasation on Post-Revascularization Computed Tomography Mimics Magnetic Resonance Hyperintense Acute Reperfusion Marker: A Case Study.

Hyperintense reperfusion marker (HARM) on post-contrast magnetic resonance imaging (MRI) fluid attenuated inversion recovery (FLAIR) represents gadolinium contrast extravasation in the setting of acute ischemic stroke and is a common finding after revascularization therapies. Clinically, it is a marker of blood brain barrier (BBB) disruption, predictor of hemorrhagic transformation, and predictor of poor clinical outcome in ischemic stroke. Here, we describe a case where a patient underwent mechanical thrombectomy and was later found to have evidence of contrast extravasation on CT imaging, in the same locations found on the post-contrast FLAIR MRI, demonstrating that MRI-HARM and CT contrast extravasation may mimic similar phenomena. Thus, this case demonstrates that we may be able to extrapolate what we know about HARM detected on MRI to a CT imaging biomarker that would be more readily obtainable in most stroke patients.

Full Resolution Simulation for Evaluation of Critical Care Imaging Interpretation; Part 2: Random Effects Reveal the Interplay Between Case Difficulty, Resident Competence, and the Training Environment.

RATIONALE AND OBJECTIVES: To further characterize empirical data from a full-resolution simulation of critical care imaging coupled with post hoc grading of resident's interpretations by senior radiologists. To present results from estimating the random effects terms in a comprehensive mixed (hierarchical) regression model. MATERIALS AND METHODS: After accounting for 9 fixed effects detailed in Part 1 of this paper, we estimated normally distributed random effects, expressed in terms of score offsets for each case, resident, program, and grader. RESULTS: The fixed effects alone explained 8.8% of score variation and adding the random effects increased explanatory power of the model to account for 36% of score variation. As quantified by intraclass correlation coefficient (ICC = 28.5%; CI: 25.1-31.6) the majority of score variation is directly attributable to the case at hand. This "case difficulty" measure has reliability of 95%. Individual residents accounted for much of the remaining score variation (ICC = 5.3%; CI: 4.6-5.9) after adjusting for all other effects including level of training. The reliability of this "resident competence" measure is 82%. Residency training program influence on scores was small (ICC = 1.1%; CI: 0.42-1.7). Although a few significantly high and low ones can be identified, reliability of 73% militates for caution. At the same time, low intraprogram variation is very encouraging. Variation attributable to differences between graders was minimal (ICC = 0.58%; CI: 0.0-1.2) which reassures us that the method of scoring is reliable, consistent, and likely extensible. CONCLUSION: Full resolution simulation based evaluation of critical care radiology interpretation is being conducted remotely and efficiently at large scale. A comprehensive mixed model of the resulting scores reliably quantifies case difficulty and resident competence.

Full Resolution Simulation for Evaluation of Critical Care Imaging Interpretation; Part 1: Fixed Effects Identify Influences of Exam, Specialty, Fatigue, and Training on Resident Performance.

RATIONALE AND OBJECTIVES: To describe our full-resolution simulation of critical care imaging coupled with posthoc grading of resident's interpretations and present results from the fixed effects terms in a comprehensive mixed regression model of the resulting scores. MATERIALS AND METHODS: The system delivered full resolution DICOM studies via clinical-grade viewing software integrated with a custom built web-based workflow and reporting system. The interpretations submitted by participating residents from 47 different programs were graded (scores of 0-10) on a case by case basis by a cadre of faculty members from our department. The data from 5 yearly (2014-2018) cycles consisting of 992 separate 65 case, 8 hour simulation sessions were collated from the transaction records. We used a mixed (hierarchical) statistical model with nine fixed and four random independent variables. In this paper, we present the results from the nine fixed effects. RESULTS: There were 19,916/63,839 (27.0%, CI 26.7%-27.4%) scores in the 0-2 range (i.e., clinically significant miss). Neurological cases were more difficult with adjusted scores 2.3 (CI 1.9-3.2) lower than body/musculoskeletal cases. There was a small (0.3, CI 0.20-0.38 points) but highly significant (p<0.0001) decrease in score for the final 13/65 cases (fifth quintile) as evidence of fatigue during the last hour of an 8 hour shift. By comparing adjusted scores from mid-R1 (quarter 3) to late-R3 (quarter 12) we estimate the training effect as an increase of 2.2 (CI 1.90-2.50) points. CONCLUSION: Full resolution simulation based evaluation of critical care radiology interpretation is being conducted remotely and efficiently at large scale. Analysis of the resulting scores yields multiple insights into the interpretative process.

Patterns of contrast enhancement in the brain and meninges.

Contrast material enhancement for cross-sectional imaging has been used since the mid 1970s for computed tomography and the mid 1980s for magnetic resonance imaging. Knowledge of the patterns and mechanisms of contrast enhancement facilitate radiologic differential diagnosis. Brain and spinal cord enhancement is related to both intravascular and extravascular contrast material. Extraaxial enhancing lesions include primary neoplasms (meningioma), granulomatous disease (sarcoid), and metastases (which often manifest as mass lesions). Linear pachymeningeal (dura-arachnoid) enhancement occurs after surgery and with spontaneous intracranial hypotension. Leptomeningeal (pia-arachnoid) enhancement is present in meningitis and meningoencephalitis. Superficial gyral enhancement is seen after reperfusion in cerebral ischemia, during the healing phase of cerebral infarction, and with encephalitis. Nodular subcortical lesions are typical for hematogenous dissemination and may be neoplastic (metastases) or infectious (septic emboli). Deeper lesions may form rings or affect the ventricular margins. Ring enhancement that is smooth and thin is typical of an organizing abscess, whereas thick irregular rings suggest a necrotic neoplasm. Some low-grade neoplasms are "fluid-secreting," and they may form heterogeneously enhancing lesions with an incomplete ring sign as well as the classic "cyst-with-nodule" morphology. Demyelinating lesions, including both classic multiple sclerosis and tumefactive demyelination, may also create an open ring or incomplete ring sign. Thick and irregular periventricular enhancement is typical for primary central nervous system lymphoma. Thin enhancement of the ventricular margin occurs with infectious ependymitis. Understanding the classic patterns of lesion enhancement--and the radiologic-pathologic mechanisms that produce them--can improve image assessment and differential diagnosis.

The value of allogeneic bone marrow transplant in patients with acute myeloid leukaemia at differing risk of relapse: results of the UK MRC AML 10 trial.

Patients under 55 years in the United Kingdom Medical Research Council Acute Myeloid Leukaemia 10 trial who entered complete remission were tissue typed (n = 1063). Four hundred and nineteen had a matched sibling donor and 644 had no match. When compared on a donor versus no donor basis the relapse risk was reduced in the donor arm (36%vs 52%; P = 0.001) and the disease-free survival (DFS) improved (50%vs 42%; P = 0.01), but overall survival (OS) was not different (55%vs 50%; P = 0.1). Sixty-one per cent of patients with a donor underwent transplantation. When patients were subdivided into risk groups based on cytogenetics alone or with the addition of blast response to course 1, a reduction in relapse risk was seen in all risk groups and in three age cohorts (0-14, 15-34 and 35+ years). Significant benefit in DFS was only seen in the intermediate-risk cytogenetic group (50%vs 39%; P = 0.004). The OS benefit was only seen in intermediate-risk patients (55%vs 44%; P = 0.02). The reduction in relapse risk in good-risk patients was attributable to patients with t(15;17) and not to patients with t(8;21) or inv(16). Allogeneic transplantation given after intensive chemotherapy was able to reduce relapse in all risk and age groups. However, due to the competing effects of procedural mortality and an inferior response to chemotherapy if relapse does occur, there was a survival advantage only in patients of intermediate risk. This trial found no survival advantage in children, patients over 35 years or good-risk disease.