Neurology最新文献

Background and objectives: In recent years, researchers have sought to address the challenges of obtaining informed consent for participation in acute stroke trials. We studied outcomes related to the use of deferral of consent in the phase 3 Alteplase Compared to Tenecteplase (AcT) trial.

Methods: As part of our protocol, we captured methods of consent, participant withdrawals, door-to-randomization times, and door-to-needle times. Participants at 3 sites were invited to complete a survey of attitudes regarding consent for AcT and for acute stroke trials generally.

Results: The AcT trial enrolled 1,600 participants from 22 centers across Canada of whom 1,537 were enrolled through deferral of consent (96.0%) and 63 (4.0%) were enrolled by prospective verbal consent followed by written informed consent. Of those enrolled by deferral of consent, 95% (1,454/1,537) consented to ongoing participation. Door-to-randomization times were similar regardless of method of consent, with an overall median of 30 minutes (interquartile range [IQR] 22-42): 29 minutes (IQR 22-42) in the deferral of consent group vs 32 minutes (IQR 25-44) in the prospective consent group (p = 0.1602). Survey respondents overwhelming agreed or strongly agreed with the use of deferral of consent in AcT (86%) and in any acute stroke trial (76%).

Discussion: Deferral of consent was broadly acceptable to participants in the AcT trial as demonstrated by low rates of withdrawal and by survey results. Door-to-randomization times using deferral of consent in AcT were short, although a system of prospective verbal consent used at 1 center took only slightly longer. These results support the importance of innovation around consent for acute stroke trials.

Background and objectives: Disentangling brain aging from disease-related neurodegeneration in patients with multiple sclerosis (PwMS) is increasingly topical. The brain-age paradigm offers a window into this problem but may miss disease-specific effects. In this study, we investigated whether a disease-specific model might complement the brain-age gap (BAG) by capturing aspects unique to MS.

Methods: In this retrospective study, we collected 3D T1-weighted brain MRI scans of PwMS to build (1) a cross-sectional multicentric cohort for age and disease duration (DD) modeling and (2) a longitudinal single-center cohort of patients with early MS as a clinical use case. We trained and evaluated a 3D DenseNet architecture to predict DD from minimally preprocessed images while age predictions were obtained with the DeepBrainNet model. The brain-predicted DD gap (the difference between predicted and actual duration) was proposed as a DD-adjusted global measure of MS-specific brain damage. Model predictions were scrutinized to assess the influence of lesions and brain volumes while the DD gap was biologically and clinically validated within a linear model framework assessing its relationship with BAG and physical disability measured with the Expanded Disability Status Scale (EDSS).

Results: We gathered MRI scans of 4,392 PwMS (69.7% female, age: 42.8 ± 10.6 years, DD: 11.4 ± 9.3 years) from 15 centers while the early MS cohort included 749 sessions from 252 patients (64.7% female, age: 34.5 ± 8.3 years, DD: 0.7 ± 1.2 years). Our model predicted DD better than chance (mean absolute error = 5.63 years, R² = 0.34) and was nearly orthogonal to the brain-age model (correlation between DD and BAGs: r = 0.06 [0.00-0.13], p = 0.07). Predictions were influenced by distributed variations in brain volume and, unlike brain-predicted age, were sensitive to MS lesions (difference between unfilled and filled scans: 0.55 years [0.51-0.59], p < 0.001). DD gap significantly explained EDSS changes (B = 0.060 [0.038-0.082], p < 0.001), adding to BAG (ΔR² = 0.012, p < 0.001). Longitudinally, increasing DD gap was associated with greater annualized EDSS change (r = 0.50 [0.39-0.60], p < 0.001), with an incremental contribution in explaining disability worsening compared with changes in BAG alone (ΔR² = 0.064, p < 0.001).

Discussion: The brain-predicted DD gap is sensitive to MS-related lesions and brain atrophy, adds to the brain-age paradigm in explaining physical disability both cross-sectionally and longitudinally, and may be used as an MS-specific biomarker of disease severity and progression.

Background and objectives: Cerebral amyloid angiopathy (CAA) is common in older adults and is associated with dementia. Less is known whether this association is mediated by Alzheimer disease (AD) neuropathologic changes, the examination of which was the objective of this study.

Methods: This was a retrospective cross-sectional examination of the Kaiser Permanente Washington database of the Adult Changes in Thought (ACT) autopsy cohort with information on CAA, dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) (amyloid neuritic plaques), and Braak (tau neurofibrillary tangles). CAA was diagnosed by immunohistochemistry and dementia by ACT Consensus Diagnostic Conference. AD neuropathology was categorized by CERAD scores and Braak stages. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% CIs of the associations of CAA with dementia, adjusting for age at death and sex, and with additional adjustments separately for CERAD scores (moderate-severe vs mild-absent), Braak stages (V-VI vs 0-IV), APOE ε4, and stroke. Formal mediation analyses were conducted to estimate age-sex-adjusted OR (95% CI) for natural indirect effects (NIEs) of CERAD scores and Braak stages.

Results: The 848 participants had a mean age of 86.7 ± 4.6 years at death, and 57.6% were female. CAA was present in 322 participants (38.0%), of whom 152, 145, and 25 had mild, moderate, and severe CAA, respectively. Dementia was present in 384 participants (45.3%), of whom 317 had AD. Dementia was more common in those with CAA than without (53.7% vs 40.1%; age-sex-adjusted OR 1.57, 95% CI 1.18-2.10). This association remained significant after separate adjustment for other covariates but lost significance when adjusted for CERAD scores (OR 1.27, 95% CI 0.93-1.71) and Braak stages (OR 0.96, 95% CI 0.69-1.33). Findings from our formal mediation analyses show that ORs (95% CIs) for NIE of CERAD scores and Braak stages were 1.25 (1.13-1.37) and 1.63 (1.38-1.88), respectively, and CERAD scores and Braak stages mediated 53% and 111% of the total association, respectively.

Discussion: We observed a significant association between CAA and dementia that disappeared when adjusted for CERAD or Braak stages. Findings from our mediation analyses suggest that the CAA-dementia association may be potentially mediated by AD neuropathologic changes. This hypothesis needs to be tested in future mechanistic studies in AD accounting for unmeasured confounders.

Background and objectives: Although most spontaneous intracerebral hemorrhages (ICHs) are due to cerebral small vessel diseases (SVDs), between 1 in 7 and 1 in 10 are due to a macrovascular cause. Rapid diagnosis has important therapeutic and prognostic implications but sometimes requires digital subtraction angiography (DSA), an invasive procedure which cannot be performed in all patients. MRI provides optimal sensitivity for markers of SVD but was not included in previous risk stratification scores. We aimed to create and validate a risk stratification score for macrovascular causes of ICH including MRI findings to guide diagnosis and further investigations.

Methods: We pooled data from 2 large observational study cohorts (London/United Kingdom and Graz/Austria) of consecutive patients with ICH who had brain MRI and at least 1 angiographic modality within 90 days of symptom onset. The primary outcome was a macrovascular cause of ICH (arteriovenous malformation/dural arteriovenous fistula, aneurysm, cavernoma, or cerebral venous thrombosis), with the diagnosis based on neurovascular multidisciplinary meetings. Using lasso logistic regression, we built the MRI Assessment of the Causes of intRacerebral haemOrrhage (MACRO) score to assess the probability of a macrovascular cause. We performed internal validation using bootstrapping and external validation in an independent cohort (Bern/Switzerland).

Results: We included 1,043 patients with ICH (mean age 66 years, 42% female), 78 of whom had a macrovascular cause (7.5%). The final score includes age (0-39, 40-69, or ≥70), location of ICH (lobar, deep, or infratentorial), and SVD markers on MRI (≥1 microbleed, ≥1 lacune, presence of cortical superficial siderosis, or white matter hyperintensities using the Fazekas scale). The MACRO score showed an optimism-adjusted c-statistic of 0.90 (95% CI 0.88-0.93), superior to existing CT-based scores (p < 0.001). In external validation, the c-statistic was 0.87 (95% CI 0.80-0.94). MACRO scores ≥6 (59.5% of patients) indicated a very low risk of a macrovascular cause (0.2%), while scores ≤2 (9% of patients) indicated a high risk (48.9%).

Discussion: The MRI-based MACRO score shows excellent performance in predicting the likelihood of macrovascular causes of spontaneous intracerebral hemorrhage, making it useful in guiding further investigations. Important limitations include the observational study design and the performance of DSA in a minority of patients.