Opportunities in multimodal neuroimaging for optimizing thrombolytic therapy for ischemic stroke

Abstract

The main purpose of examination of patients before thrombolytic therapy for ischemic stroke (IS) is to timely identify contraindications to the use of recombinant tissue plasminogen activator. Objective: to estimate opportunities and benefits in applying multimodal magnetic resonance imaging (MRI) to improve clinical outcomes in acute stroke, among other processes, by enhancing the efficiency and safety of thrombolytic therapy. Patients and methods . The clinical experience of the S.M. Kirov Military Medical Academy in using multimodal MRI of the brain since 2004 was analyzed in patients with stroke. Results. Comprehensive assessment of the results of perfusion-weighted MRI of the brain and those of transcranial Doppler ultrasound identified five clinically significant variants of perfusion changes in IS: normal perfusion; postischemic hyperemia; persistent hypoperfusion; acute pathological hyperperfusion, and unrecovered perfusion. With an irreversible tissue damage volume of >60 cm3 on day 1 of stroke, as evidenced by diffusion-weighted MRI, the odd ratio for cerebral edema in the acutest period of the disease is 39.4% (95% CI 2.57–2436; p<0.05). The risk of hemorrhagic transformation increases with a measured diffusion coefficient in the area of the nucleus of developing nonlacunar infarct <35×10-5 mm2/sec within the first 24 hours after disease onset (p<0.005). Conclusion. The data of local clinical practice and the results of international clinical trials show that multimodal MRI of the brain is a reliable tool for the detailed evaluation of the expected efficiency and safety of thrombolytic therapy for IS. When persistent hypoperfusion is detected, the determination of perfusion-diffusion mismatch is of no informative value in deciding on whether thrombolytic therapy can be performed. Estimating the volume of pathological changes on diffusion-weighted images and the measured diffusion coefficient in the area of the nucleus of developing nonlacunar infarct in the measured diffusion coefficient maps allows the risk of major intracranial complications due to IS to be identified.