Enlarging and shrinking focal perivascular spaces.

BACKGROUND AND PURPOSE: Perivascular spaces (PVS) are interstitial fluid-filled spaces surrounding blood vessels traversing the deep gray nuclei and white matter of the brain. These are commonly encountered on CT and MR imaging and are generally asymptomatic and of no clinical significance. However, occasional changes in the size of focal PVS, for example, when enlarging, may mimic pathologies including neoplasms and infections, hence potentially confounding radiological interpretation. Given these potential diagnostic issues, we sought to better characterize common clinical and imaging features of focal PVS demonstrating size fluctuations. MATERIALS AND METHODS: Upon institutional approval, we retrospectively identified 4 cases demonstrating PVS with size changes at our institution. To supplement our cases, we also performed a literature review, which identified an additional 14 cases. Their clinical and imaging data were analyzed to identify characteristic features. RESULTS: Of the 18 total cases (including the 4 institutional cases), 10 cases increased and 8 decreased in size. These focal PVS ranged from 0.4-4.5 cm in size. Whereas a decrease in size did not represent a diagnostic issue, focal increase in size of PVS led to concerning differential diagnoses in at least 30% of the radiology reports. These enlarging PVS were most found in the basal ganglia and temporal lobe, and in patients with previous brain radiation treatment. CONCLUSION: Focal size change of PVS can occur, especially years after brain radiation treatment. Being cognizant of this benign finding is important to consider in the differential diagnosis to avoid undue patient anxiety or unnecessary medical intervention.

Anti-Ma2 Antibody-Mediated Paraneoplastic Cerebellar Degeneration and Myeloneuropathy Secondary to Lymphoma.

ABSTRACT: A 61-year-old woman with a history of untreated low-grade B-cell lymphoma presented with blurry vision, unsteadiness, and worsening pain on touching skin of the upper trunk was enrolled. Blurry vision was attributed to oscillopsia from downbeat nystagmus, which later evolved into macrosaccadic oscillations. MRI brain and spine showed mild, longitudinally extensive T2 hyperintensity in the central gray matter of the spinal cord extending from the medulla to T11 level. Serum paraneoplastic panel was negative; however, she had very high titers of anti-Ma2 antibodies in cerebrospinal fluid. The diagnosis of paraneoplastic neurological syndrome was made. Empiric treatment with high dose of intravenous steroids followed by intravenous immunoglobulin infusions did not improve her symptoms. An extensive search for an underlying tumor commenced and was initially unrevealing. However, two-month follow-up positron emission tomography scan showed increased uptake in a right pulmonary nodule, which when biopsied confirmed diagnosis of extranodal marginal zone lymphoma. The final diagnosis was anti-Ma2 antibody-mediated paraneoplastic cerebellar degeneration and myeloneuropathy secondary to lymphoma.

Carotid Plaque-RADS: A Novel Stroke Risk Classification System.

BACKGROUND: Carotid artery atherosclerosis is highly prevalent in the general population and is a well-established risk factor for acute ischemic stroke. Although the morphological characteristics of vulnerable plaques are well recognized, there is a lack of consensus in reporting and interpreting carotid plaque features. OBJECTIVES: The aim of this paper is to establish a consistent and comprehensive approach for imaging and reporting carotid plaque by introducing the Plaque-RADS (Reporting and Data System) score. METHODS: A panel of experts recognized the necessity to develop a classification system for carotid plaque and its defining characteristics. Using a multimodality analysis approach, the Plaque-RADS categories were established through consensus, drawing on existing published reports. RESULTS: The authors present a universal classification that is applicable to both researchers and clinicians. The Plaque-RADS score offers a morphological assessment in addition to the prevailing quantitative parameter of "stenosis." The Plaque-RADS score spans from grade 1 (indicating complete absence of plaque) to grade 4 (representing complicated plaque). Accompanying visual examples are included to facilitate a clear understanding of the Plaque-RADS categories. CONCLUSIONS: Plaque-RADS is a standardized and reliable system of reporting carotid plaque composition and morphology via different imaging modalities, such as ultrasound, computed tomography, and magnetic resonance imaging. This scoring system has the potential to help in the precise identification of patients who may benefit from exclusive medical intervention and those who require alternative treatments, thereby enhancing patient care. A standardized lexicon and structured reporting promise to enhance communication between radiologists, referring clinicians, and scientists.

Prevalence of Venous Infarction in Patients With Cerebral Venous Thrombosis: Baseline Diffusion-Weighted MRI and Follow-Up MRI.

BACKGROUND: A venous pattern of infarction on neuroimaging is used as a clue to undiagnosed cerebral venous thrombosis (CVT); prevention of venous infarction is a goal of CVT management; and venous infarction is a factor used for clinical prognostication. Despite widespread use of the term venous infarct, the prevalence of true venous infarction is unclear. Our primary aim was to determine the prevalence of venous infarction in patients with CVT. We also measured the prevalence of diffusion abnormality without infarction, vasogenic edema, and intracranial hemorrhage. METHODS: Single-center, retrospective cohort study using a registry of 110 consecutive patients admitted to hospital with cerebral venous thrombosis between 2004 and 2014. Inclusion criteria were brain magnetic resonance imaging (MRI) and contrast-enhanced venography at presentation, and repeat brain MRI ≥1 month later. Exclusion criteria were dural arteriovenous fistula, arteriovenous malformation, cavernous sinus thrombosis, or previous neurosurgical procedure. Main outcome was proportion of patients with venous infarction (irreversible ischemic injury) diagnosed using diffusion-weighted MRI at presentation, confirmed using T2-weighted fluid-attenuated inversion recovery MRI ≥1 month later, and reported with 95% CI using the Wilson score interval method. We also report the prevalence of transient diffusion MRI abnormality without infarction, vasogenic edema, and intracranial hemorrhage. RESULTS: Seventy-three patients met the inclusion criteria, and after exclusions, the final study population was 59 patients with median age 41 years (interquartile range, 32-57). Venous infarction occurred in 12% (7/59 [95% CI, 6%-23%]) of patients, and final infarct volume was >1 mL in only 5.1% (3/59) of patients. An additional 8% (5/59 [95% CI, 4%-18%]) of patients had a transient diffusion MRI abnormality without infarction. Prevalence of cerebral vasogenic edema and intracranial hemorrhage were 66% (39/59 [95% CI, 53%-77%]) and 54% (32/59 [95% CI, 41%-66%]), respectively. CONCLUSIONS: In patients with CVT, venous infarction is uncommon and venous infarcts are typically very small. Vasogenic edema and hemorrhage are more common consequences of CVT.

Surgical left atrial appendage occlusion with concomitant cardiac surgical procedures: exacerbating heart failure or preventing stroke.

PURPOSE OF REVIEW: The left atrial appendage (LAA) is a common source of thromboembolic stroke in patients with atrial fibrillation. Current guidelines recommend consideration of surgical LAA occlusion concomitant with other cardiac surgical procedures based mostly on observational data and a few small trials. Recently published results of several large retrospective studies and one prospective trial are reviewed herein. RECENT FINDINGS: Large retrospective studies using quality and administrative databases show mixed results with regard to efficacy of surgical LAA occlusion in preventing stroke, although most showed stroke reduction in patients with a history of atrial fibrillation (AF). Safety concerns have been raised based on nonrandomized data suggesting increased complications. A recent large, multicenter international randomized study with 3-year follow-up demonstrated significant reduction in stroke following LAA occlusion with no differences in death or heart failure exacerbations. SUMMARY: Most patients with AF undergoing another cardiac surgical procedure should be considered for concomitant LAA occlusion as part of a heart team discussion. The choice of surgical closure technique is critical. There is insufficient data to recommend LAA occlusion as an alternative to anticoagulation.

Reversible neurological and brain MRI changes following COVID-19 vaccination: A case report.

BACKGROUND: Various neurological sequalae have been described following COVID-19 vaccination. Here we describe the first case of untreated post COVID-19 vaccine encephalitis with spontaneous resolution of contrast enhancing hyperintensities on MRI concomitant with clinical improvement. CASE PRESENTATION: A 59-year-old woman presented with a two-day history of unsteady gait, incoordination, visual symptoms, and lethargy. She had received AZD1222 (AstraZeneca) and mRNA-1273 (Moderna) COVID-19 vaccines at 3 months and 12 days, respectively, before presentation. Brain MRI showed no abnormality on the non-enhanced sequences, but numerous enhancing lesions in the cerebral cortex, deep grey matter, brainstem, and cerebellum. Treatment was expectant, the patient improved clinically over 10 days, and repeat MRI showed near complete resolution of the imaging abnormality. CONCLUSIONS: We describe neurological deterioration 12 days after a second dose of COVID-19 vaccine. There was no evidence of edema or demyelinating lesions in the brain on MRI, but there was extensive contrast-enhancement indicating loss of blood-brain barrier (BBB) integrity. This provides a potential in vivo, clinical-imaging correlate of the post-mortem evidence that SARS-CoV-2 spike protein may induce loss of BBB permeability. While this adds to the list of rare adverse neurological reactions to COVID-19 vaccination, the benefits of receiving the vaccine far outweigh these risks.

An Approach to Standard Perioperative Transthoracic Echocardiography Practice for Anesthesiologists-Perioperative Transthoracic Echocardiography Protocols.

The use of intraoperative transesophageal echocardiography (TEE) has become the standard of care for most cardiac surgical procedures. There are guidelines established for training, practice, and quality improvement in perioperative TEE by the joint efforts of the American Society of Echocardiography and Society of Cardiovascular Anesthesiologists. Cardiac point-of-care ultrasound (POCUS) increasingly is being incorporated into anesthesiologists' training and practice. While a special "certification in Critical Care Echocardiography" was created by the National Board of Echocardiography in 2019, there currently exist no guidelines for training, certification, and practice of perioperative TTE by anesthesiologists. In this review, the authors describe the categories, indications and applications of perioperative TTE and provide a recommended sequence for performing an examination tailored to the evaluation of perioperative patients. Although the authors describe a protocol utilized at their institution, there are no standards described in the literature for PTTE. Cardiac anesthesiologists and cardiac anesthesia societies (Society of Cardiovascular Anesthesiologists, European Association of Cardiothoracic Anesthesiologists) must come forward to establish standards working in collaboration with echocardiography societies (American Society of Echocardiography, European Society of Cardiology).

Synthetic auxotrophy remains stable after continuous evolution and in coculture with mammalian cells.

Understanding the evolutionary stability and possible context dependence of biological containment techniques is critical as engineered microbes are increasingly under consideration for applications beyond biomanufacturing. While synthetic auxotrophy previously prevented Escherichia coli from exhibiting detectable escape from batch cultures, its long-term effectiveness is unknown. Here, we report automated continuous evolution of a synthetic auxotroph while supplying a decreasing concentration of essential biphenylalanine (BipA). After 100 days of evolution, triplicate populations exhibit no observable escape and exhibit normal growth rates at 10-fold lower BipA concentration than the ancestral synthetic auxotroph. Allelic reconstruction reveals the contribution of three genes to increased fitness at low BipA concentrations. Based on its evolutionary stability, we introduce the progenitor strain directly to mammalian cell culture and observe containment of bacteria without detrimental effects on HEK293T cells. Overall, our findings reveal that synthetic auxotrophy is effective on time scales and in contexts that enable diverse applications.

Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging.

Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values.

Assessment of Recurrent Stroke Risk in Patients With a Carotid Web.

Importance: A carotid web (CW) is a shelf-like lesion along the posterior wall of the internal carotid artery bulb and an underrecognized cause of young stroke. Several studies suggest that patients with symptomatic CW have a high risk of recurrent stroke, but high-quality data are lacking. Objective: To assess the 2-year risk of recurrent stroke in patients with a symptomatic CW. Design, Setting, and Participants: A comparative cohort study used data from the MR CLEAN trial (from 2010-2014) and MR CLEAN Registry (from 2014-2017). Data were analyzed in September 2020. The MR CLEAN trial and MR CLEAN Registry were nationwide prospective multicenter studies on endovascular treatment (EVT) of large vessel occlusion (LVO) stroke in the Netherlands. Baseline data were from 3439 consecutive adult patients with anterior circulation LVO stroke and available computed tomography (CT)-angiography of the carotid bulb. Two neuroradiologists reevaluated CT-angiography images for presence or absence of CW and identified 30 patients with CW ipsilateral to the index stroke. For these 30 eligible CW participants, detailed follow-up data regarding stroke recurrence within 2 years were acquired. These 30 patients with CW ipsilateral to the index stroke were compared with 168 patients without CW who participated in the MR CLEAN extended follow-up trial and who were randomized to the EVT arm. Main Outcomes and Measures: The primary outcome was recurrent stroke occurring within 2 years after the index stroke. Cox proportional hazards regression models were used to compare recurrent stroke rates within 2 years for patients with and without CW, adjusted for age and sex. The research question was formulated prior to data collection. Results: Of 3439 patients with baseline CT-angiography assessed, the median age was 72 years (interquartile range, 61-80 years) and 1813 (53%) were men. Patients with CW were younger (median age, 57 [interquartile range, 46-66] years vs 66 [interquartile range, 56-77] years; P = .02 and more often women (22 of 30 [73%] vs 67 of 168 [40%]; P = .001) than patients without CW. Twenty-eight of 30 patients (93%) received medical management after the index stroke (23 with antiplatelet therapy and 5 with anticoagulant therapy). During 2 years of follow-up, 5 of 30 patients (17%) with CW had a recurrent stroke compared with 5 of 168 patients (3%) without CW (adjusted hazard ratio, 4.9; 95% CI, 1.4-18.1). Conclusions and Relevance: In this study, 1 of 6 patients with a symptomatic CW had a recurrent stroke within 2 years, suggesting that medical management alone may not provide sufficient protection for patients with CW.

Rothia dentocariosa causing intracranial mycotic aneurysm and ischaemic stroke.

We describe a case of subacute bacterial endocarditis and mycotic brain aneurysm caused by Rothia dentocariosa due to untreated dental caries. R. dentocariosa is a rare cause of endocarditis that has a high incidence of aneurysmal and haemorrhagic complications. All patients with intracranial aneurysms who have signs of systemic infection should be considered to have mycotic aneurysms until proven otherwise. Dental habits should be included in regular medical assessment and dental care should be considered for patients presenting with infectious symptoms.

EGFR-Binding Peptides: From Computational Design towards Tumor-Targeting of Adeno-Associated Virus Capsids.

The epidermal growth factor receptor (EGFR) plays a central role in the progression of many solid tumors. We used this validated target to analyze the de novo design of EGFR-binding peptides and their application for the delivery of complex payloads via rational design of a viral vector. Peptides were computationally designed to interact with the EGFR dimerization interface. Two new peptides and a reference (EDA peptide) were chemically synthesized, and their binding ability characterized. Presentation of these peptides in each of the 60 capsid proteins of recombinant adeno-associated viruses (rAAV) via a genetic based loop insertion enabled targeting of EGFR overexpressing tumor cell lines. Furthermore, tissue distribution and tumor xenograft specificity were analyzed with systemic injection in chicken egg chorioallantoic membrane (CAM) assays. Complex correlations between the targeting of the synthetic peptides and the viral vectors to cells and in ovo were observed. Overall, these data demonstrate the potential of computational design in combination with rational capsid modification for viral vector targeting opening new avenues for viral vector delivery and specifically suicide gene therapy.