P133 Main clinical variables that impact lesion characterization and outcome in ischemic stroke imaging

<h3>Introduction</h3> Stroke remains a leading cause of worldwide morbidity and mortality. Understanding the relation between its clinical and imaging characteristics is crucial for effective management. <h3>Aim of Study</h3> To evaluate how time since stroke onset and clinical variables affect the divergence in stroke size segmentation between non-contrast cranial computed tomography(NCCT) and apparent diffusion coefficient(ADC) imaging, using a self-developed artificial intelligence(AI) software in patients with acute ischemic anterior circulation stroke within 24 hours from symptom onset. <h3>Methods</h3> An anonymized cohort of patients diagnosed with ischemic stroke, in whom brain magnetic resonance imaging(MRI), diffusion-weighted imaging(DWI), ADC, and NCCT were performed, with manual segmentation carried out by two neuro-interventional radiologists using the MRICroGL software to outline the ischemic area in NCCT and MRI. Divergence was established as a lesion visible on MRI but not on NCCT. <h3>Results</h3> Seventy-seven patients with a median age of 77 years (IQR:64-85) were included, with a predominance of female sex(52%). None had a previous history of ischemic stroke, and 69% of the patients had comorbidities, arterial hypertension(62%) being the most prevalent. Lower stroke size volume in each method showed higher volume between the first 5 hours since stroke onset. Spearman’s Rho correlations showed significant association: infarction size in both modalities(0.402), NIHSS at admission and mRS at discharge(0.432), and NCCT infarction volume and segmentation divergence( -0.884). <h3>Conclusion</h3> Stroke size and progression time are crucial for enhancing diagnostic accuracy in AI training. NCCT smaller lesions showed more divergence with MRI. Beyond 5 hours from stroke onset, we found no significant difference between both images.