Purpose:To demonstrate the feasibility of 129 Xe MR in evaluating the pulmonary physiological changes caused by PM 2.5 in animal models. Methods: Six rats were treated with PM 2.5 solution (16.2 mg/kg) by intratracheal instillation twice a week for 4 weeks, and another six rats treated with normal saline served as the control cohort. Pulmonary function tests, hyperpolarized 129 Xe multi-b diffusion-weighted imaging, and chemical shift saturation recovery MR spectroscopy were performed on all rats, and the pulmonary structure and functional parameters were obtained from hyperpolarized 129 Xe MR data. Additionally, histological analysis was performed on all rats to evaluate alveolar septal thickness. Statistical analysis of all the obtained parameters was performed using unpaired 2-tailed t tests. Results: Compared with the control group, the measured exchange time constant increased from 11.74 ± 2.39 to 14.00 ± 2.84 ms (P < .05), and the septal wall thickness increased from 6.17 ± 0.48 to 6.74 ± 0.52 μm (P < .05) in the PM 2.5 cohort by 129 Xe MR spectroscopy, which correlated well with that obtained using quantitative histology (increased from 5.52 ± 0.32 to 6.20 ± 0.36 μm). Additionally, the mean TP/GAS ratio increased from 0.828 ± 0.115 to 1.019 ± 0.140 in the PM 2.5 cohort (P = .021). Conclusions: Hyperpolarized 129 Xe MR could quantify the changes in gas exchange physiology caused by PM 2.5 , indicating that the technique has the potential to be a useful tool for evaluation of pulmonary injury caused by air pollution in the future. K E Y W O R D Sair pollution, gas exchange, hyperpolarized 129 Xe, lung injury, PM 2.5 570 | ZHANG et Al.

Aims: Our purpose is to assess the role of cerebral small vessel disease (SVD) in prediction models in patients with different subtypes of acute ischemic stroke (AIS). Methods:We enrolled 398 small-vessel occlusion (SVO) and 175 large artery atherosclerosis (LAA) AIS patients. Functional outcomes were assessed using the modified Rankin Scale (mRS) at 90 days. MRI was performed to assess white matter hyperintensity (WMH), perivascular space (PVS), lacune, and cerebral microbleed (CMB). Logistic regression (LR) and machine learning (ML) were used to develop predictive models to assess the influences of SVD on the prognosis. Results:In the feature evaluation of SVO-AIS for different outcomes, the modified total SVD score (Gain: 0.38, 0.28) has the maximum weight, and periventricular WMH (Gain: 0.07, 0.09) was more important than deep WMH (Gain: 0.01, 0.01) in prognosis.In SVO-AIS, SVD performed better than regular clinical data, which is the opposite | 1025 WANG et al.

BACKGROUND AND PURPOSE: The ability of the ivy sign on contrast-enhanced T1-weighted MR imaging (CEMR) to reflect cerebral perfusion and postoperative revascularization in Moyamoya disease remains largely unknown. We aimed to compare the capabilities of CEMR and FLAIR. MATERIALS AND METHODS: CEMR, FLAIR, arterial spin-labeling, and DSA were performed in 44 patients with Moyamoya disease. The ivy sign was scored separately on CEMR and FLAIR using the Alberta Stroke Program Early CT Score. The status of leptomeningeal collaterals was scored on DSA. The postoperative Matsushima grade was evaluated at least 3 months after surgical revascularization. RESULTS: Scoring of the ivy sign on CEMR showed excellent interrater reliability, and FLAIR vascular hyperintensity showed moderate interrater reliability. Correlation analyses revealed that DSA scores were more consistent with the CEMR-based ivy sign score (r ¼ 0.25, P ¼ .03) than with FLAIR vascular hyperintensity (r ¼ 0.05, P ¼ .65). The CEMR-based ivy sign score was significantly correlated with CBF in late-Suzuki stage Moyamoya disease (t ¼ À2.64, P ¼ .02). The CEMR-based ivy sign score at baseline was significantly correlated with the postoperative Matsushima grade (r ¼ 0.48, P ¼ .03). CONCLUSIONS: In this study, CEMR outperformed FLAIR in capturing the ivy sign in Moyamoya disease. In addition, the CEMR-based ivy sign score provided adequate information on hemodynamic status and postoperative neovascularization. The current study suggested that CEMR could be considered as an alternative to FLAIR in future studies investigating leptomeningeal collaterals in Moyamoya disease. ABBREVIATIONS: CEMR ¼ contrast-enhanced T1-weighted MR imaging; FVH ¼ FLAIR vascular hyperintensity; MMD ¼ Moyamoya disease; PCA ¼ posterior cerebral artery; EDAS ¼ encephaloduroarteriosynangiosis; FOV ¼ field of view M oyamoya disease (MMD) is an uncommon cerebrovascular disease characterized by chronic progressive occlusion of the terminal portion of the internal carotid artery and its main branches within the circle of Willis. 1,2 In MMD, the perfusion of brain tissue originates from the narrowed ICA, basal moyamoya vessels, leptomeningeal collaterals derived chiefly from the posterior circulation, and transdural collaterals from the external carotid

Background Glioma genotypes are of importance for clinical decision‐making. This data can only be acquired through histopathological analysis based on resection or biopsy. Consequently, there is a need for alternative biomarkers that noninvasively provide reliable information for preoperatively identifying molecular characteristics. Purpose To investigate apparent diffusion coefficient (ADC) as imaging biomarker for preoperatively identifying glioma genotypes based on the 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors. Study Type Retrospective. Subjects One hundred and fifty‐nine patients (47.6 ± 14.4 years) diagnosed with WHO grade 2–4 glioma including 93 males and 66 females. Field Strength/Sequence A 3 T/spin echo echo planner imaging. Assessment The ADC measurements were assessed by two neuroradiologists (both with 6 years of experience). Three different lowest portions inside the tumors without overlap were manually drawn on the ADC maps as regions of interest (ROIs). The mean ADC value of the three ROIs was defined as the minimum ADC value (ADCmin). An ROI was placed in the contralateral normal appearing white matter (NAWM) to obtain the ADC value (ADCNAWM). The ADCmin to ADCNAWM ratio (ADCratio) was calculated. Genetics results were retrospectively recorded from pathologic and genetic test reports. Statistical Tests Two‐sample independent t‐tests, receiver operating characteristic curve analysis, and intraclass correlation coefficient analysis were used. Statistical significance was set at P < 0.05. Results Isocitrate dehydrogenase (IDH)‐mutated glioma showed higher ADCmin and ADCratio than IDH wild‐type glioma. Among IDH‐mutated glioma, higher ADCmin and ADCratio were found in 1p19q intact glioma than in 1p19q codeletion glioma. ADC parameters enabled differentiation of IDH mutation status with area under the curve (AUC) of 0.84 and 0.86. Data Conclusion ADC has potential discriminative value for IDH mutation and 1p19q codeletion status. Evidence Level 3. Technical Efficacy Stage 2.

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