Exploring the Relationship between Lesion Morphology and Pathogenesis in Acute Small Subcortical Infarction

Abstract

<b><i>Introduction:</i></b> Acute small subcortical infarctions (SSIs) result from occlusions of small penetrating arteries, and the underlying pathological factors can have different clinical implications. The objective of this study was to assess the clinical relevance of acute SSIs based on their sizes and morphologies. <b><i>Methods:</i></b> This retrospective case-control study analyzed clinical and imaging data of stroke patients with acute SSIs in penetrating artery territories who underwent magnetic resonance imaging within 5 days of stroke onset, registered between 2016 and 2020. We categorized these patients into three groups based on size and morphology: diameter &lt;20 mm, diameter ≥20 mm, and separated lesions. We then evaluated their clinical characteristics and outcomes. <b><i>Results:</i></b> We analyzed 726 stroke patients with SSIs, among whom 573 had a diameter &lt;20 mm, 99 had a diameter ≥20 mm, and 54 had separated lesions. The patients had a median age of 70 years and a median National Institutes of Health Stroke Scale (NIHSS) score of 4 on arrival. Patients who experienced early neurological deterioration (END) had a significantly lower chance of good functional outcomes (27.3% vs. 64.4%, <i>p</i> &lt; 0.001). Patients with a diameter ≥20 mm had the most severe NIHSS on arrival and at day 3, the highest rate of END, and the lowest rate of good outcome at 3 months. The incidence of cardioembolism did not differ between patients with diameters of ≥20 mm and &lt;20 mm. However, multiple logistic regression analysis revealed that separated lesions were more likely to be associated with cardioembolic stroke (adjusted odds ratio [aOR], 7.6; 95% confidence interval [CI], 2.0–28.5) and parent artery stenosis &gt;50% (aOR, 3.8; 95% CI, 2.1–7.0) than a diameter of &lt;20 mm. Moreover, SSIs with a diameter of ≥20 mm were found to be associated with an increased risk of END compared to those with a diameter of &lt;20 mm (aOR, 2.9; 95% CI, 1.7–5.2). <b><i>Conclusion:</i></b> Our study suggests that the sizes and morphologies of acute SSIs may indicate different underlying pathologies and be linked to diverse clinical outcomes. Our findings also challenge the current imaging criteria for embolic stroke of undetermined source, as we did not find a link between large subcortical infarction and cardioembolic stroke.