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INTRODUCTION: The aim of the study was to assess the impact of collaterals on the evolution of hypodensity on non-contrast CT (NCCT) in anterior circulation stroke with reperfusion by mechanical thrombectomy (MT). METHODS: We retrospectively included stroke patients with middle cerebral artery occlusion who were reperfused by MT in early and late time window. Artificial intelligence (AI)-based software was used to calculate of hypodensity volumes at baseline NCCT (V1) and at follow-up NCCT 24 h after MT (V2), along with the difference between the two volumes (V2-V1) and the follow-up (V2)/baseline (V1) volume ratio (V2/V1). The same software was used to classify collateral status by using a 4-point scale where the score of zero indicated no collaterals and the score of three represented contrast filling of all collaterals. The volumetric values were correlated with the collateral scores. RESULTS: Collateral scores had significant negative correlation with V1 (p = 0.035), V2, V2- V1 and V2/V1 (p < 0.001). In cases with collateral score = 3, V2 was significantly smaller or absent compared to V1; in those with collateral score 2, V2 was slightly larger than V1, and in those with scores 1 and 0 V2 was significantly larger than V1. These relationships were observed in both early and late time windows. CONCLUSIONS: The collateral status determined the evolution of the baseline hypodensity on NCCT in patients with anterior circulation stroke who had MT reperfusion. Damage can be stable or reversible in patients with good collaterals while in those with poor collaterals tissues that initially appear normal will frequently appear as necrotic after 24 h. With good collaterals, it is stable or can be reversible while with poor collaterals, normal looking tissue frequently appears as necrotic in follow-up exam. Hence, acute hypodensity represents different states of the ischemic brain parenchyma.
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BACKGROUND: In patients with SAH and multiple aneurysms, the ruptured lesion must be identified to prevent recurrent bleeding. AIM OF THE STUDY: To assess the diagnostic value of non-enhanced computed tomography (NECT) in identifying the rupture site in patients with subarachnoid haemorrhage (SAH) and multiple aneurysms. MATERIAL AND METHODS: We included patients with SAH revealed by NECT and multiple aneurysms detected on computed tomography angiography (CTA) in whom a ruptured aneurysm was identified during neurosurgery. Two radiologists predicted the location of the ruptured aneurysm based on the distribution of the SAH and location of intracerebral haematoma (ICH) by NECT. RESULTS: Eighty-three patients with a mean age of 55.7 ± 14.4 years were included. Ruptured aneurysms were significantly larger (mean size 7.7 ± 4.7 mm) than unruptured aneurysms (mean size 5.9 ± 4.5 mm; p = 0.014). Interobserver agreement was 0.86 (p < 0.001). Overall sensitivity and specificity of radiological prediction were 78.3% (95% CI, 68.6%-87.1%) and 96.4% (95% CI, 94.3%-97.8%) respectively. Overall PPV and NPV were 78.3% (95% CI, 67.6%-86.3%) and 96.8% (95% CI, 94.8%-98.1%) respectively. The sensitivity and PPV for aneurysms in the anterior communicating, anterior, and middle cerebral arteries appeared to be significantly higher than in other locations (p = 0.015 and 0.019 respectively). Analysis of independent predictive factors of correct radiological location revealed that ICH predisposes to a correct radiological diagnosis with an odds ratio of 8.57 (95% CI, 1.07-68.99; p = 0.03). CONCLUSIONS: NECT has a high diagnostic value in identifying the source of bleeding in patients with multiple aneurysms for anterior circulation aneurysms, especially with coexisting ICH. For other locations, NECT is not reliable enough to base treatment decisions upon.