Establishment of an African green monkey model for COVID-19 and protection against re-infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for an unprecedented global pandemic of COVID-19. Animal models are urgently needed to study the pathogenesis of COVID-19 and to screen vaccines and treatments. We show that African green monkeys (AGMs) support robust SARS-CoV-2 replication and develop pronounced respiratory disease, which may more accurately reflect human COVID-19 cases than other nonhuman primate species. SARS-CoV-2 was detected in mucosal samples, including rectal swabs, as late as 15 days after exposure. Marked inflammation and coagulopathy in blood and tissues were prominent features. Transcriptome analysis demonstrated stimulation of interferon and interleukin-6 pathways in bronchoalveolar lavage samples and repression of natural killer cell- and T cell-associated transcripts in peripheral blood. Despite a slight waning in antibody titers after primary challenge, enhanced antibody and cellular responses contributed to rapid clearance after re-challenge with an identical strain. These data support the utility of AGM for studying COVID-19 pathogenesis and testing medical countermeasures.

Paraneoplastic Syndromes from Head to Toe: Pathophysiology, Imaging Features, and Workup.

Patients often have symptoms due to the mass effect of a neoplasm on surrounding tissues or the development of distant metastases. However, some patients may present with clinical symptoms that are not attributable to direct tumor invasion. In particular, certain tumors may release substances such as hormones or cytokines or trigger an immune cross-reactivity between malignant and normal body cells, resulting in characteristic clinical features that are broadly referred to as paraneoplastic syndromes (PNSs). Recent advances in medicine have improved the understanding of the pathogenesis of PNSs and enhanced their diagnosis and treatment. It is estimated that 8% of patients with cancer develop a PNS. Diverse organ systems may be involved, most notably the neurologic, musculoskeletal, endocrinologic, dermatologic, gastrointestinal, and cardiovascular systems. Knowledge of various PNSs is necessary, as these syndromes may precede tumor development, complicate the patient's clinical presentation, indicate tumor prognosis, or be mistaken for metastatic spread. Radiologists should be familiar with the clinical presentations of common PNSs and the selection of appropriate imaging examinations. Many of these PNSs have imaging features that can assist with arriving at the correct diagnosis. Therefore, the key radiographic findings associated with these PNSs and the diagnostic pitfalls that can be encountered during imaging are important, as their detection can facilitate early identification of the underlying tumor, reveal early recurrence, and enable monitoring of the patient's response to therapy. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Utility of Repeat MRI in Patients With Degenerative Cervical Disease.

Existing guidelines regarding indications for initial cervical spine magnetic resonance imaging (MRI) do not indicate when to perform repeat MRI in patients with previously documented degenerative disease. This study evaluates the efficacy of repeat MRI in patients with previously diagnosed degenerative cervical disease. Between 2013 and 2018, 153 patients (102 women, 51 men; mean age, 55 years; range, 19-81 years) without a history of trauma or surgery underwent cervical spine MRI 2 or more times at our institution indicated for symptoms of neck pain with or without radiculopathy. The MRI reports of repeat studies were reviewed and compared with index studies for notable changes. Notable radiographic changes were defined as any progression of the existing degenerative disease. Fifty-three of 153 (35%) patients demonstrated progression on repeat MRI. Forty-nine of the 53 patients demonstrating progression had new or worsening symptoms prior to their follow-up study (P=.03). Twenty-nine of 35 (83%) patients with new or worsening radiculopathy progressed on MRI (P<.01). Nine of 10 (90%) patients with new upper motor neuron findings demonstrated progression (P=.01). Axial neck pain alone was not statistically linked to MRI progression (P=.1). Twenty-five (16.3%) patients underwent operative management for their disease. Only 12 (48.0%) of the surgical patients presented MRI progression (P=.1). In the absence of new or worsening degenerative cervical symptoms, additional MRI studies are unlikely to reveal any radiographic progression or change clinical management from nonoperative to operative. [Orthopedics. 2023;46(2):98-102.].

Attending Reviews of Residents Correlate with ABR Qualifying (Core) Examination Failure.

RATIONALE AND OBJECTIVES: Since the American Board of Radiology (ABR) instituted the new system of board certification, there has been much discussion as to the test's validity. We decided to evaluate if subjective evaluation of resident performance correlated with ABR Qualifying (Core) Examination performance at this single institution. MATERIALS AND METHODS: Data regarding resident evaluation scores by attending physicians and passage of board examinations was gathered regarding residents who had taken the ABR Qualifying (Core) Examination from 2013 through 2019 for a total of 42 residents, eight of whom failed the ABR Qualifying (Core) Examination on their first attempt. A univariate analysis comparing scores with resident passage or failure of the ABR Qualifying (Core) Examination on the first attempt and analyses correcting for class year only and class year and number of evaluations was performed. RESULTS: The non-weighted average evaluation score of years 1, 2, and 3 was 80.24% for those who failed the ABR Qualifying (Core) Examination and 83.71 % for those who passed. On univariate analysis along with analyses correcting for class year only and class year along with number of evaluations, there was a statistically significant correlation with decreased evaluation scores averaged over the three years of residency and failure of the ABR Qualifying (Core) Examination (p = 0.0102, p = 0.003, and p = 0.0043). The statistical significance held for the average numerical score in each individual year of training in all analyses except for year 1 of the univariate analysis (p = 0.1264). CONCLUSION: At the studied institution, there was a statistically significant correlation between lower subjective faculty evaluation scores and failure of the ABR Qualifying (Core) Examination.

Establishment of an African green monkey model for COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for an unprecedented global pandemic of COVID-19. Animal models are urgently needed to study the pathogenesis of COVID-19 and to screen candidate vaccines and treatments. Nonhuman primates (NHP) are considered the gold standard model for many infectious pathogens as they usually best reflect the human condition. Here, we show that African green monkeys support a high level of SARS-CoV-2 replication and develop pronounced respiratory disease that may be more substantial than reported for other NHP species including cynomolgus and rhesus macaques. In addition, SARS-CoV-2 was detected in mucosal samples of all animals including feces of several animals as late as 15 days after virus exposure. Importantly, we show that virus replication and respiratory disease can be produced in African green monkeys using a much lower and more natural dose of SARS-CoV-2 than has been employed in other NHP studies.

Novel finding of optic nerve central T2 hypointensity utilizing 3 Tesla MR imaging.

We sought to report a central T2 hypointensity within the optic nerve on 3 T MRI studies obtained as part of the NASA Flight Medicine Visual Impairment Intracranial Pressure Protocol that had not been described previously. Twenty-one astronauts, who had undergone MRI of both orbits with direct coronal T2 sequences between 2010 and 2012, were retrospectively included. Two of the astronauts did not have previous exposure to microgravity at the time of their scans. A central T2 hypointensity was observed in 100% of both right and left eyes. It was completely visualized throughout the nerve course in 15 right eyes (71.4%) and in 19 left eyes (90.5%).We describe a new finding seen in all study participants: a central T2 hypointensity in the epicenter of the optic nerve. We speculate that this T2 hypointensity may represent flow voids caused by the central retinal vessels.