Measuring waning protection from seasonal influenza vaccination during nine influenza seasons, Ontario, Canada, 2010/11 to 2018/19.

BackgroundWaning immunity from seasonal influenza vaccination can cause suboptimal protection during peak influenza activity. However, vaccine effectiveness studies assessing waning immunity using vaccinated and unvaccinated individuals are subject to biases.AimWe examined the association between time since vaccination and laboratory-confirmed influenza to assess the change in influenza vaccine protection over time.MethodsUsing linked laboratory and health administrative databases in Ontario, Canada, we identified community-dwelling individuals aged ≥ 6 months who received an influenza vaccine before being tested for influenza by RT-PCR during the 2010/11 to 2018/19 influenza seasons. We estimated the adjusted odds ratio (aOR) for laboratory-confirmed influenza by time since vaccination (categorised into intervals) and for every 28 days.ResultsThere were 53,065 individuals who were vaccinated before testing for influenza, with 10,264 (19%) influenza-positive cases. The odds of influenza increased from 1.05 (95% CI: 0.91-1.22) at 42-69 days after vaccination and peaked at 1.27 (95% CI: 1.04-1.55) at 126-153 days when compared with the reference interval (14-41 days). This corresponded to 1.09-times increased odds of influenza every 28 days (aOR = 1.09; 95% CI: 1.04-1.15). Individuals aged 18-64 years showed the greatest decline in protection against influenza A(H1N1) (aORper 28 days = 1.26; 95% CI: 0.97-1.64), whereas for individuals aged ≥ 65 years, it was against influenza A(H3N2) (aORper 28 days = 1.20; 95% CI: 1.08-1.33). We did not observe evidence of waning vaccine protection for individuals aged < 18 years.ConclusionsInfluenza vaccine protection wanes during an influenza season. Understanding the optimal timing of vaccination could ensure robust protection during seasonal influenza activity.

Intimate Partner Violence-Related Brain Injury: Unmasking and Addressing the Gaps.

Intimate partner violence (IPV) is a significant, global public health concern. Women, individuals with historically underrepresented identities, and disabilities are at high risk for IPV and tend to experience severe injuries. There has been growing concern about the risk of exposure to IPV-related head trauma, resulting in IPV-related brain injury (IPV-BI), and its health consequences. Past work suggests that a significant proportion of women exposed to IPV experience IPV-BI, likely representing a distinct phenotype compared with BI of other etiologies. An IPV-BI often co-occurs with psychological trauma and mental health complaints, leading to unique issues related to identifying, prognosticating, and managing IPV-BI outcomes. The goal of this review is to identify important gaps in research and clinical practice in IPV-BI and suggest potential solutions to address them. We summarize IPV research in five key priority areas: (1) unique considerations for IPV-BI study design; (2) understanding non-fatal strangulation as a form of BI; (3) identifying objective biomarkers of IPV-BI; (4) consideration of the chronicity, cumulative and late effects of IPV-BI; and (5) BI as a risk factor for IPV engagement. Our review concludes with a call to action to help investigators develop ecologically valid research studies addressing the identified clinical-research knowledge gaps and strategies to improve care in individuals exposed to IPV-BI. By reducing the current gaps and answering these calls to action, we will approach IPV-BI in a trauma-informed manner, ultimately improving outcomes and quality of life for those impacted by IPV-BI.

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.

Extracranial carotid artery atherosclerotic plaque and APOE polymorphisms: a systematic review and meta-analysis.

Introduction: Carotid atherosclerotic plaque is an important independent risk factor for stroke. Apolipoprotein E (APOE) influences cholesterol levels and certain isoforms are associated with increased carotid atherosclerosis, though the exact association between APOE and carotid plaque is uncertain. The study aimed to evaluate the association between APOE and carotid plaque. Methods: A systematic review was performed to retrieve all studies which examined the association between carotid plaque and APOE. This study was conducted in accordance with the PRISMA guidelines. Independent readers extracted the relevant data from each study including the type of imaging assessment, plaque definition, frequency of APOE E4 carrier status and type of genotyping. Meta-analyses with an assessment of study heterogeneity and publication bias were performed. Results were presented in a forest plot and summarized using a random-effects model. Results: After screening 838 studies, 17 studies were included for systematic review. A meta-analysis of 5 published studies showed a significant association between ε4 homozygosity and carotid plaque [odds ratio (OR), 1.53; 95% CI, 1.16, 2.02; p = .003]. Additionally, there was a significant association between patients possessing at least one ε4 allele, heterozygotes or homozygotes, and carotid plaque (OR, 1.25; 95% CI, 1.03, 1.52; p = .03). Lastly, there was no association between ε4 heterozygosity and carotid plaque (OR, 1.08; 95% CI, 0.93, 1.26; p = .30). Conclusion: APOE ε4 allele is significantly associated with extracranial carotid atherosclerotic plaque, especially for homozygous individuals.

Evaluation of methemoglobin as an intravascular contrast agent: T1 relaxation time effect in a rabbit model.

OBJECTIVE: Alternative contrast agents for MRI are needed for individuals who may respond adversely to gadolinium, and need an intravascular agent for specific indications. One potential contrast agent is intracellular methemoglobin, a paramagnetic molecule that is normally present in small amounts in red blood cells. An animal model was used to determine whether methemoglobin modulation with intravenous sodium nitrite transiently changes the T1 relaxation of blood. METHODS: Four adult New Zealand white rabbits were treated with 30 mg intravenous sodium nitrite. 3D TOF and 3D MPRAGE images were acquired before (baseline) and after methemoglobin modulation. T1 of blood was measured with 2D ss EPl acquisitions with inversion recovery preparation performed at two-minute intervals up to 30 min. T1 maps were calculated by fitting the signal recovery curve within major blood vessels. RESULTS: Baseline T1 was 1758 ± 53 ms in carotid arteries and 1716 ± 41 ms in jugular veins. Sodium nitrite significantly changed intravascular T1 relaxation. The mean minimum value of T1 was 1126 ± 28 ms in carotid arteries 8 to 10 min after the injection of sodium nitrite. The mean minimum value of T1 was 1171 ± 52 ms in jugular veins 10 to 14 min after the injection of sodium nitrite. Arterial and venous T1 recovered to baseline after a period of 30 min. CONCLUSION: Methemoglobin modulation produces intravascular contrast on T1-weighted MRI in vivo. Additional studies are needed to safely optimize methemoglobin modulation and sequence parameters for maximal tissue contrast.

Estimating the Incidence of First RSV Hospitalization in Children Born in Ontario, Canada.

BACKGROUND: Respiratory syncytial virus (RSV) contributes significantly to morbidity in children, placing substantial burdens on health systems, thus RSV vaccine development and program implementation are a public health priority. More data on burden are needed by policymakers to identify priority populations and formulate prevention strategies as vaccines are developed and licensed. METHODS: Using health administrative data, we calculated incidence rates of RSV hospitalization in a population-based birth cohort of all children born over a six-year period (May 2009 to June 2015) in Ontario, Canada. Children were followed until their first RSV hospitalization, death, 5th birthday, or the end of the study period (June 2016). RSV hospitalizations were identified using a validated algorithm based on International Classification of Diseases, 10th Revision, and/or laboratory-confirmed outcomes. We calculated hospitalization rates by various characteristics of interest, including calendar month, age groups, sex, comorbidities, and gestational age. RESULTS: The overall RSV hospitalization rate for children <5 years was 4.2 per 1000 person-years (PY) with a wide range across age groups (from 29.6 to 0.52 per 1000 PY in children aged 1 month and 36-59 months, respectively). Rates were higher in children born at a younger gestational age (23.2 per 1000 PY for those born at <28 weeks versus 3.9 per 1000 PY born at ≥37 weeks); this increased risk persisted as age increased. While the majority of children in our study had no comorbidities, rates were higher in children with comorbidities. For all age groups, rates were highest between December and March. CONCLUSIONS: Our results confirm the high burden of RSV hospitalization and highlight young infants are at additional risk, namely premature infants. These results can inform prevention efforts.

Evaluating the Impact of Statin Use on Influenza Vaccine Effectiveness and Influenza Infection in Older Adults.

BACKGROUND: Older adults are recommended to receive influenza vaccination annually, and many use statins. Statins have immunomodulatory properties that might modify influenza vaccine effectiveness (VE) and alter influenza infection risk. METHODS: Using the test-negative design and linked laboratory and health administrative databases in Ontario, Canada, we estimated VE against laboratory-confirmed influenza among community-dwelling statin users and nonusers aged ≥66 years during the 2010-2011 to 2018-2019 influenza seasons. We also estimated the odds ratio for influenza infection comparing statin users and nonusers by vaccination status. RESULTS: Among persons tested for influenza across the 9 seasons, 54 243 had continuous statin exposure before testing and 48 469 were deemed unexposed. The VE against laboratory-confirmed influenza was similar between statin users and nonusers (17% [95% confidence interval, 13%-20%] and 17% [13%-21%] respectively; test for interaction, P = .87). In both vaccinated and unvaccinated persons, statin users had higher odds of laboratory-confirmed influenza than nonusers (odds ratios for vaccinated and unvaccinated persons 1.15 [95% confidence interval, 1.10-1.21] and 1.15 [1.10-1.20], respectively). These findings were consistent by mean daily dose and statin type. VE did not differ between users and nonusers of other cardiovascular drugs, except for ß-blockers. We did not observe that vaccinated and unvaccinated users of these drugs had increased odds of influenza, except for unvaccinated ß-blocker users. CONCLUSIONS: Influenza VE did not differ between statin users and nonusers. Statin use was associated with increased odds of laboratory-confirmed influenza in vaccinated and unvaccinated persons, but these associations might be affected by residual confounding.

A Pilot Study of a Screening Program for Human Papillomavirus-Related Squamous Intraepithelial Lesion and Malignancy in Gynecologic Oncology Patients.

OBJECTIVE: Human papillomavirus (HPV)-related squamous intraepithelial lesion (SIL) or malignancy is associated with a significantly increased risk of second-site SIL or malignancy. The primary objective of this study was to determine the feasibility and acceptability of concurrent anal, cervical, and vulvovaginal screening in patients with a history of HPV-related gynecologic high-grade SIL or malignancy. The secondary objective was to assess subjects' knowledge regarding HPV screening and risks. METHODS: Women with high-grade cervical, vulvar, or vaginal SIL or malignancy were enrolled during a 1-year pilot period. Subjects with cervical SIL or malignancy underwent vulvar examination and anoscopy. Subjects with vulvovaginal SIL or malignancy underwent Pap test if indicated and anoscopy. Appropriate referrals were made for abnormal findings. Feasibility was assessed by compliance using study acceptance rate, screening procedure adherence, and referral adherence. Acceptability was assessed using a Likert-scaled question after completion of screening procedures. RESULTS: One hundred three women with a diagnosis of high-grade vulvovaginal or cervical SIL or carcinoma were approached regarding study enrollment; of these, 74 (71.8%) enrolled. The median score on the HPV knowledge assessment was 8.1 ± 1.6 (max score 10). Seventy-three (98.6%) of 74 patients rated the screening procedures as acceptable (score of 5/5). On examination, 14 (18.9%) subjects had abnormalities noted; 7 (9.5%) were referred for colorectal surgical evaluation, and 6/7 (85.7%) were compliant with their referral appointments. CONCLUSIONS: Screening examinations for other HPV-related SILs and malignancies, including Pap tests, vulvovaginal inspection, and anoscopy, are acceptable to patients, with abnormal findings in almost 1 in 5 women.

A comparison of simultaneous multislice and conventional diffusion tensor imaging techniques for ischemic stroke evaluation at 1.5T.

OBJECTIVE: Diffusion tensor imaging (DTI) is a promising technique for ischemic stroke evaluation; however, acquisition time is longer than DWI. Simultaneous multislice (SMS) imaging acquires multiple slices together and reduces scan time. This study compared conventional and SMS DTI for ischemic stroke workup. METHODS: Following IRB approval, the departmental stroke protocol was supplemented with SMS DTI on a clinical 1.5T MRI. Cases suspicious for ischemic stroke outside the treatment window were included. Standard DTI (STD-DTI, 20-direction, b = 2000 s/mm2), was followed by SMS-2-DTI (two slices simultaneously imaged). Two blinded neuroradiologists independently assessed image quality and DTI-trace status (positive/negative = stroke/other). Average image quality, interrater reliability (κ), receiver operating characteristic area under the curve (AUC), signal-to-noise ratio (SNR = DTI-source min/max/average), coefficient of variation (CV), mean diffusivity (MD), and fractional anisotropy (FA, of DTI-trace) were compared using two-tailed t-tests and a p < .05. RESULTS: 41 patients were evaluated. SMS-2-DTI decreased DTI time by 132.17 ± 15.33 s, a 45% reduction. SMS-2-DTI reduced image quality (STD-DTI 4.7 ± 0.5 vs SMS-2-DTI 3.8 ± 0.6, p < .001). Diagnostic accuracy persisted, AUC was high for observer 1 (STD-DTI 0.95, 95%CI = 0.88-1.00 vs SMS-2-DTI 0.94, 95%CI = 0.87-1.00, p = .86) and observer 2 (STD-DTI 0.89, 95%CI = 0.79-0.99 vs SMS-2-DTI 0.86, 95%CI = 0.76-0.97, p = .66). Interrater reliability was high for STD-DTI (κ = 0.80, 95%CI = 0.61-0.98) and SMS-2-DTI (κ = 0.84, 95%CI = 0.67-1.00). SMS-2-DTI significantly decreased average SNR (STD-DTI 42.85 ± 4.44 vs SMS-2-DTI 32.58 ± 4.30, p < .001), and CV MD (STD-DTI 0.23 ± 0.03 vs 0.20 ± 0.04, p < .001). CV FA and CV DTI-trace were not statistically different. CONCLUSIONS: This study supports using SMS to accelerate DTI for ischemic stroke workup at 1.5T in the non-hyper-acute setting. ADVANCES IN KNOWLEDGE: This study highlights the feasibility of accelerated multislice DTI for faster diagnostic DTI-trace images capable of ischemic stroke detection.

Association between high-risk extracranial carotid plaque and covert brain infarctions and cerebral microbleeds.

PURPOSE: Covert brain infarctions (CBIs) and cerebral microbleeds (CMBs) represent subclinical sequelae of ischemic and hemorrhagic cerebral small vessel disease, respectively. In addition to thromboembolic stroke, carotid atherosclerosis has been associated with downstream vascular brain injury, including inflammation and small vessel disease. The specific plaque features responsible for this are unknown. We aimed to determine the association of specific vulnerable carotid plaque features to CBIs and CMBs to better understand the relation of large and small vessel disease in a single-center retrospective observational study. METHODS: Intraplaque hemorrhage (IPH) and plaque ulceration were recorded on carotid MRA and total, cortical, and lacunar CBIs and CMBs were recorded on brain MR in 349 patients (698 carotid arteries). Multivariable Poisson regression was performed to relate plaque features to CBIs and CMBs. Within-subject analysis in those with unilateral IPH and ulceration was performed with Poisson regression. RESULTS: Both IPH and plaque ulceration were associated with total CBI (prevalence ratios (PR) 3.33, 95% CI: 2.16-5.15 and 1.91, 95% CI: 1.21-3.00, respectively), after adjusting for stenosis, demographic, and vascular risk factors. In subjects with unilateral IPH, PR was 2.83, 95% CI: 1.76-4.55, for CBI in the ipsilateral hemisphere after adjusting for stenosis. Among those with unilateral ulceration, PR was 1.82, 95% CI: 1.18-2.81, for total CBI ipsilateral to ulceration after adjusting for stenosis. No statistically significant association was seen with CMBs. CONCLUSION: Both IPH and plaque ulceration are associated with total, cortical, and lacunar type CBIs but not CMBs suggesting that advanced atherosclerosis contributes predominantly to ischemic markers of subclinical vascular injury.

MRI Detection of Carotid Intraplaque Hemorrhage and Postintervention Cognition.

BACKGROUND AND PURPOSE: Cognitive improvement has been reported after carotid revascularization and attributed to treating stenosis and correcting hypoperfusion. This study investigated the effect of carotid intraplaque hemorrhage on postintervention cognition. MATERIALS AND METHODS: In this institutional review board-approved single-center study, consecutive patients scheduled for carotid surgery were recruited for preoperative carotid MR imaging (MPRAGE) and pre- and postintervention cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status. Pre- and postintervention scores were compared using t tests and multivariable linear regression. RESULTS: Twenty-three participants were included, with endarterectomy performed in 20 (87%) and angioplasty/stent placement, in 3 (13%). Overall, statistically significant improvements occurred in the pre- versus postintervention mean Total Scale score (92.1 [SD, 15.5] versus 96.1 [SD, 15.8], P = .04), immediate memory index (89.4 [SD, 18.2] versus 97.7 [SD, 14.9], P < .001), and verbal index (96.1 [SD, 14.1] versus 103.0 [SD, 12.0], P = .002). Intraplaque hemorrhage (+) participants (n = 11) had no significant improvement in any category, and the attention index significantly decreased (99.4 [SD, 18.0] versus 93.5 [SD, 19.4], P = .045). Intraplaque hemorrhage (-) participants (n = 12) significantly improved in the Total Scale score (86.4 [SD, 11.8] versus 95.5 [SD, 12.4], P = .004), immediate memory index (82.3 [SD, 14.6] versus 96.2 [SD, 14.1], P = .002), delayed memory index (94.3 [SD, 14.9] versus 102.4 [SD, 8.0], P = .03), and verbal index (94.3 [SD, 13.2] versus 101.5 [SD, 107.4], P = .009). Postintervention minus preintervention scores for intraplaque hemorrhage (+) versus (-) groups showed statistically significant differences in the Total Scale score (-0.4 [SD, 6.8] versus 8.0 [SD, 8.5], P = .02), attention index (-5.9 [SD, 8.5] versus 4.3 [SD, 11.9], P = .03), and immediate memory index (4.2 [SD, 6.7] versus 12.2 [SD, 10.2], P = .04). CONCLUSIONS: Cognitive improvement was observed after carotid intervention, and this was attributable to intraplaque hemorrhage (-) plaque. MR imaging detection of intraplaque hemorrhage status may be an important determinant of cognitive change after intervention.

Emergent neurovascular imaging in patients with blunt traumatic injuries.

Blunt cerebrovascular injuries (BCVIs) are commonly encountered after blunt trauma. Given the increased risk of stroke incurred after BCVI, it is crucial that they are promptly identified, characterized, and treated appropriately. Current screening practices generally consist of computed tomography angiography (CTA), with escalation to digital subtraction angiography for higher-grade injuries. Although it is quick, cost-effective, and readily available, CTA suffers from poor sensitivity and positive predictive value. A review of the current literature was conducted to examine the current state of emergent imaging for BCVI. After excluding reviews, irrelevant articles, and articles exclusively available in non-English languages, 36 articles were reviewed and included in the analysis. In general, as CTA technology has advanced, so too has detection of BCVI. Magnetic resonance imaging (MRI) with sequences such as vessel wall imaging, double-inversion recovery with black blood imaging, and magnetization prepared rapid acquisition echo have notably improved the utility for MRI in characterizing BCVIs. Finally, transcranial Doppler with emboli detection has proven to be associated with strokes in anterior circulation injuries, further allowing for the identification of high-risk lesions. Overall, imaging for BCVI has benefited from a tremendous amount of innovation, resulting in better detection and characterization of this pathology.

Imaging spectrum of extracranial arterial vascular pathology: pearls for the radiologist.

Non-invasive imaging plays an increasingly important role in assessing the extracranial vasculature. The applications of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) continue to expand with growing demand for stroke imaging and anatomical assessment preceding vascular intervention. Imaging of the neck is performed for a variety of clinical indications with different imaging protocols. Even on non-dedicated vascular imaging, such as soft-tissue studies, the neck vessels and the proximal aortic arch are readily evaluable, providing an opportunity to promptly identify critical vascular abnormalities with significant therapeutic implications. Vascular abnormalities can have non-specific clinical signs and symptoms resulting in delays in both diagnosis and treatment. Understanding the common locations and appearances of vascular pathologies will help the radiologist to develop a systematic search strategy for evaluating neck imaging. Not only is identifying the pathology of paramount importance but also understanding how imaging further prognosticates and determines treatment options. As imaging techniques advance, further vascular radiological features are recognised with therapeutic implications, particularly for stroke. Such features include plaque morphology and vulnerability with imaging helping to identify those at high risk of stroke and recurrent strokes. Using clinical cases from a quaternary care academic medical centre a spectrum of clinically relevant arterial pathologies and associated features that could add further benefit to the radiology report are illustrated. A suggested systematic approach to evaluating the vasculature on neck imaging is also presented.

Carotid Compliance and Parahippocampal and Hippocampal Volume over a 20-Year Period.

INTRODUCTION: We evaluated the association between carotid compliance, a measure of arterial stiffness, to parahippocampal volume (PHV) and hippocampal volume (HV) over 20 years later in the Atherosclerosis Risk in the Community study. METHODS: We included participants with common carotid compliance measurements at visit 1 (1987-1989) and volumetric brain MRI at visit 5 (2011-2013). The primary outcomes are pooled bilateral PHV and HV. We performed linear regression models adjusting for age, sex, vascular risk factors, and total brain volume. RESULTS: Of the 614 participants, higher compliance was correlated with higher PHV (R = 0.218[0.144-0.291], p < 0.001) and HV (R = 0.181 [0.105-0.255, p < 0.001]). The association was linear and significant after adjusting for confounders. At follow-up MRI, 30 patients with dementia had lower PHV and HV than patients without dementia (p < 0.001 and p < 0.001, respectively). CONCLUSION: Carotid compliance is associated with higher PHV and HV when measured 20 years later, further supporting the link between arterial stiffness and cognitive decline.

MR Angiography Series: Neurovascular MR Angiography.

Neurovascular MR angiography (MRA) is an evolving imaging technique and is crucial for the workup of numerous neurologic disorders. While CT angiography (CTA) provides a more rapid imaging assessment, in select patients it can impart a small risk of contrast material-induced nephrotoxicity or radiation-associated cancers. In addition, MRA offers some advantages over CTA for neurovascular evaluation, including higher temporal resolution and the capability for vessel wall imaging. This module is the third in a series created on behalf of the Society for Magnetic Resonance Angiography (SMRA), a group of researchers and clinicians who are passionate about the benefits of MRA but understand its challenges. The full digital presentation is available online. Work of the U.S. Government published under an exclusive license with the RSNA.

Health care costs of hospitalization of young children for respiratory syncytial virus infections: a population-based matched cohort study.

BACKGROUND: Respiratory syncytial virus (RSV) infection poses a substantial clinical burden among infants and young children. We sought to determine the health care costs of hospitalizations attributable to RSV in Ontario, Canada, from the health care payer perspective. METHODS: For this population-based matched cohort study, we identified children younger than 24 months who were or were not hospitalized with RSV infections in 2006-2016. We performed a cost-of-illness analysis using linked administrative health data, with subjects stratified by gestational age and congenital heart disease, and propensity score-matched on established risk factors. The primary outcome was attributable health care costs per patient, reflecting the difference in direct medical costs between the groups, calculated to 12 months postdischarge in 2020 Canadian dollars. RESULTS: We identified 14 608 RSV-infected children, matched to 72 040 controls. The adjusted attributable cost of hospitalized RSV was $134 931 900 over 10 years, or $9240 per patient (95% confidence interval [CI] $8790-$9690). Health care costs escalated 3 days before hospitalization, and persisted up to 12 months after discharge. Increased costs were associated with major comorbidities, but not extreme premature birth. The highest mean attributable cost per patient was in the presence of hemodynamically significant heart disease ($60 110, 95% CI $26 700-$93 060). Infants born at 36-43 weeks' gestation constituted the greatest overall cost burden at $117 886 720. INTERPRETATION: Although the greatest direct medical costs per patient hospitalized with RSV infection are among children with cardiac disease, the greatest overall cost burden is from children born at or near term, who are not targeted by current prophylaxis strategies. The substantial attributable health care costs of RSV can inform cost-effectiveness analyses of novel RSV vaccines and prioritization of health care resources.

MR Perfusion in the Evaluation of Mechanical Thrombectomy Candidacy.

ABSTRACT: Stroke is a leading cause of disability and mortality, and the incidence of ischemic stroke is projected to continue to rise in coming decades. These projections emphasize the need for improved imaging techniques for accurate diagnosis allowing effective treatments for ischemic stroke. Ischemic stroke is commonly evaluated with computed tomography (CT) or magnetic resonance imaging (MRI). Noncontrast CT is typically used within 4.5 hours of symptom onset to identify candidates for thrombolysis. Beyond this time window, thrombolytic therapy may lead to poor outcomes if patients are not optimally selected using appropriate imaging. MRI provides an accurate method for the earliest identification of core infarct, and MR perfusion can identify salvageable hypoperfused penumbra. The prognostic value for a better outcome in these patients lies in the ability to distinguish between core infarct and salvageable brain at risk-the ischemic penumbra-which is a function of the degree of ischemia and time. Many centers underutilize MRI for acute evaluation of ischemic stroke. This review will illustrate how perfusion-diffusion mismatch calculated from diffusion-weighted MRI and MR perfusion is a reliable approach for patient selection for stroke therapy and can be performed in timeframes that are comparable to CT-based algorithms while providing potentially superior diagnostic information.

COVID-19-Associated Myelitis Involving the Dorsal and Lateral White Matter Tracts: A Case Series and Review of the Literature.

Coronavirus disease 2019 (COVID-19) myelitis is a rare condition, most commonly presenting with nonenhancing central expansile cord T2 signal changes. A single case report has also described longitudinal involvement of the dorsal columns. We present 5 cases of COVID-19-associated myelitis with tract-specific involvement of the dorsal and lateral columns and discuss potential pathophysiologic pathways for this unique pattern.

Differentiation of symptomatic and asymptomatic carotid intraplaque hemorrhage using 3D high-resolution diffusion-weighted stack of stars imaging.

Ischemic events related to carotid disease are far more strongly associated with plaque instability than stenosis. 3D high-resolution diffusion-weighted (DW) imaging can provide quantitative diffusion measurements on carotid atherosclerosis and may improve detection of vulnerable intraplaque hemorrhage (IPH). The 3D DW-stack of stars (SOS) sequence was implemented with 3D SOS acquisition combined with DW preparation. After simulation of signals created from 3D DW-SOS, phantom studies were performed. Three healthy subjects and 20 patients with carotid disease were recruited. Apparent diffusion coefficient (ADC) values were statistically analyzed on three subgroups by using a two-group comparison Wilcoxon-Mann-Whitney U test with p values less than 0.05: symptomatic versus asymptomatic; IPH-positive versus IPH-negative; and IPH-positive symptomatic versus asymptomatic plaques to determine the relationship with plaque vulnerability. ADC values calculated by 3D DW-SOS provided values similar to those calculated from other techniques. Mean ADC of symptomatic plaque was significantly lower than asymptomatic plaque (0.68 ± 0.18 vs. 0.98 ± 0.16 x 10-3  mm2 /s, p < 0.001). ADC was also significantly lower in IPH-positive versus IPH-negative plaque (0.68 ± 0.13 vs. 1.04 ± 0.11 x 10-3  mm2 /s, p < 0.001). Additionally, ADC was significantly lower in symptomatic versus asymptomatic IPH-positive plaque (0.57 ± 0.09 vs. 0.75 ± 0.11 x 10-3  mm2 /s, p < 0.001). Our results provide strong evidence that ADC measurements from 3D DW-SOS correlate with the symptomatic status of extracranial internal carotid artery plaque. Further, ADC improved discrimination of symptomatic plaque in IPH. These data suggest that diffusion characteristics may improve detection of destabilized plaque leading to elevated stroke risk.

Vessel Wall Enhancement on Black-Blood MRI Predicts Acute and Future Stroke in Cerebral Amyloid Angiopathy.

BACKGROUND AND PURPOSE: Cerebral amyloid angiopathy (CAA) is a known risk factor for ischemic stroke though angiographic imaging is often negative. Our goal was to determine the relationship between vessel wall enhancement (VWE) in acute and future ischemic stroke in CAA patients. MATERIALS AND METHODS: This was a retrospective study of patients with new-onset neurologic symptoms undergoing 3T vessel wall MR imaging from 2015 to 2019. Vessel wall enhancement was detected on pre- and postcontrast flow-suppressed 3D T1WI. Interrater agreement was evaluated in cerebral amyloid angiopathy-positive and age-matched negative participants using a prevalence- and bias-adjusted kappa analysis. In patients with cerebral amyloid angiopathy, multivariable Poisson and Cox regression were used to determine the association of vessel wall enhancement with acute and future ischemic stroke, respectively, using backward elimination of confounders to P < .20. RESULTS: Fifty patients with cerebral amyloid angiopathy underwent vessel wall MR imaging, including 35/50 (70.0%) with ischemic stroke and 29/50 (58.0%) with vessel wall enhancement. Prevalence- and bias-corrected kappa was 0.82 (95% CI, 0.71-0.93). The final regression model for acute ischemic stroke included vessel wall enhancement (prevalence ratio = 1.5; 95% CI, 1.1-2.2; P = .022), age (prevalence ratio = 1.02; 95% CI, 1.0-1.05; P = .036), time between symptoms and MR imaging (prevalence ratio = 0.9; 95% CI, 0.8-0.9; P < .001), and smoking (prevalence ratio = 0.7; 95% CI, 0.5-1.0; P = .042) with c-statistic = 0.92 (95% CI, 0.84-0.99). Future ischemic stroke incidence with cerebral amyloid angiopathy was 49.7% (95% CI, 34.5%-67.2%) per year over a total time at risk of 37.5 person-years. Vessel wall enhancement-positive patients with cerebral amyloid angiopathy demonstrated significantly shorter stroke-free survival with 63.9% (95% CI, 43.2%-84.0%) versus 32.2% (95% CI, 14.4%-62.3%) ischemic strokes per year, chi-square = 4.9, P = .027. The final model for future ischemic stroke had a c-statistic of 0.70 and included initial ischemic stroke (hazard ratio = 3.4; 95% CI, 1.0-12.0; P = .053) and vessel wall enhancement (hazard ratio = 2.5; 95% CI, 0.9-7.0; P = .080). CONCLUSIONS: Vessel wall enhancement is associated with both acute and future stroke in patients with cerebral amyloid angiopathy.