Background/Objectives: The aim of this study was to evaluate brain metabolism using MR spectroscopy (MRS) after recovery from Coronavirus disease (COVID-19) and to test the impact of disease severity on brain metabolites. Methods: We performed MRS on 81 individuals (45 males, 36 females, aged 40–60), who had normal MRI findings and had recovered from COVID-19, classifying them into mild (17), moderate (36), and severe (28) groups based on disease severity during the acute phase. The study employed two-dimensional spectroscopic imaging above the corpus callosum, focusing on choline (Cho), creatine (Cr), and N-acetylaspartate (NAA). We analyzed Cho/Cr and NAA/Cr ratios as well as absolute concentrations using water as an internal reference. Results: Results indicated that the Cho/Cr ratio was higher with increasing disease severity, while absolute Cho and NAA/Cr ratios showed no significant differences across the groups. Notably, absolute Cr and NAA levels were significantly lower in patients with severe disease. Conclusions: These findings suggest that the severity of COVID-19 during the acute phase is associated with significant changes in brain metabolism, marked by an increase in Cho/Cr ratios and a reduction in Cr and NAA levels, reflecting substantial metabolic alterations post-recovery.

Background and Objectives: Carotid artery stenosis is a significant risk factor for ischemic stroke due to impaired cerebral blood flow (CBF). Even asymptomatic unilateral stenosis can induce subclinical cerebrovascular changes, potentially affecting both hemispheres through collateral circulation. This study aimed to systematically assess cerebral perfusion in asymptomatic individuals with unilateral carotid artery stenosis by comparing ipsilateral and contralateral hemispheres with healthy controls, challenging the assumption that the contralateral hemisphere remains unaffected. Materials and Methods: This cross-sectional study included 114 participants, comprising 54 asymptomatic individuals (mean age 65.5) with significant unilateral carotid stenosis and 60 age-matched controls (mean age 64.8). Cerebral perfusion was assessed using 1.5T Magnetic Resonance Imaging (MRI) with pseudo-continuous arterial spin labeling (pCASL). CBF was measured bilaterally in four predefined middle cerebral artery (MCA) regions: precentral gyrus, lentiform nucleus, insular cortex, and temporal cortex. Statistical analyses included multivariate analysis of variance (MANOVA), analysis of variance (ANOVA), paired t-tests, and discriminant analysis (DA). Results: Significant bilateral reductions in CBF were observed in individuals with carotid stenosis compared to controls (MANOVA and ANOVA, p < 0.001). The greatest perfusion deficit was in the ipsilateral insular cortex (49.88 ± 10.83 mL/100 g/min), followed by intermediate contralateral perfusion (51.49 ± 8.86 mL/100 g/min) and higher control values (58.78 ± 10.44 mL/100 g/min). DA indicated the insular cortex as the region with the highest discriminative contribution (64.7%). Conclusions: Unilateral carotid artery stenosis in asymptomatic individuals is associated with significant bilateral cerebral hypoperfusion, suggesting widespread hemodynamic effects. Pronounced perfusion deficits in the insular cortex underline its vulnerability. The observed contralateral perfusion reductions challenge the traditional use of the contralateral hemisphere as a reference standard, underscoring the need for comprehensive perfusion assessment in carotid artery disease.

Introduction. Tumor embolism is a recognized but uncommon cause of cancer-related stroke. Unlike systemic emboli from left atrial myxomas, tumor emboli large enough to cause symptomatic cerebral ischemia are rare. Lung carcinoma may lead to embolization through spontaneous vascular invasion or secondary to surgical manipulation, with the latter being more frequent. Case Report. We present a 60-year-old woman with a history of lung adenocarcinoma but no active metastatic disease, who was admitted to our Clinic with acute right middle cerebral artery syndrome. On admission, a head computed tomography scan showed an Alberta Stroke Program Early Computed Tomography score of 8 in the right hemisphere. A computed tomography angiogram of the head and neck revealed occlusion of the right internal carotid artery, prompting administration of intravenous tissue plasminogen activator. The following day, a routine carotid ultrasound detected an atypical heterogeneous mass on the posterior wall of the right internal carotid artery, suggestive of a metastatic embolus with distal occlusion. Further evaluation with a contrast-enhanced chest computed tomography confirmed regional metastatic dissemination, showing adenocarcinoma progression to the superior mediastinum with satellite metastatic lesions. Conclusion. This case highlights spontaneous internal carotid artery occlusion due to tumor embolus spreading from lung cancer, leading to ischemic stroke. Our findings suggest that carotid ultrasound may be superior to computed tomography angiography in identifying tumor emboli, which could influence therapeutic decision-making in similar cases.