Age-related differences in diffusion-weighted imaging lesion volume and reversal in patients with successful recanalization after mechanical thrombectomy

Background With the advancement of mechanical thrombectomy (MT), post-treatment diffusion-weighted imaging (DWI) lesion reversal (DWIR) has been reported. This study aimed to compare the volumes of DWI lesions and the frequencies of DWIR between younger and elderly patients who underwent successful recanalization with MT. Methods The study retrospectively analyzed 177 consecutive patients who underwent successful recanalization with MT for anterior large vessel occlusion (LVO) at our hospital between April 2011 and September 2022. Patients were categorized into two age groups: <70 years and >= 70 years. MRI was performed before treatment and 24 hours after treatment. The DWI lesion volumes and DWIR frequencies were compared between the two groups. Results The median age of the patients was 78 years and 19.8% were in the <70 years group. No significant differences were found between the groups in terms of occluded vessel sites and recanalization time. The baseline DWI lesion was significantly larger in the <70 years group (16.0 mL vs 4.0 mL, P<0.001). The frequency of DWIR did not significantly differ between the groups (65.7% vs 55.6%). DWI lesion volume significantly decreased after treatment in the <70 years group but showed no significant change in the >= 70 years group. Conclusions In patients who underwent successful recanalization after MT for anterior LVO, baseline DWI lesions were significantly larger in younger patients compared with elderly patients. Although more than half of the patients in both age groups experienced DWIR, a significant reduction in DWI lesion volume was only observed in younger patients.