Diffusion-perfusion MRI characterization of post-recanalization hyperperfusion in humans

Area of Science:

• Neuroimaging
• Cerebrovascular Diseases
• Interventional Neurology

Background:

• Post-ischemic hyperperfusion is a known phenomenon in both animal and human studies following acute cerebral ischemia.
• This hyperperfusion can manifest at both early and late time points after the initial ischemic event.

Purpose of the Study:

• To characterize post-thrombolysis hyperperfusion in human patients using diffusion-perfusion MRI.
• To investigate the temporal patterns and characteristics of hyperperfusion following intra-arterial thrombolysis for acute cerebral ischemia.

Main Methods:

• Diffusion-perfusion MRI scans were acquired before treatment, several hours post-recanalization, and at day 7 in patients who underwent successful intra-arterial thrombolysis.
• Analysis focused on identifying and quantifying regions of hyperperfusion and comparing them with surrounding tissues and contralateral homologous regions.

Main Results:

• Hyperperfusion was observed in approximately 40% of patients within hours and 50% by day 7 after recanalization.
• Regions of hyperperfusion showed significantly increased cerebral blood flow (2.1x early, 3.1x late) compared to contralateral regions.
• Tissues developing hyperperfusion exhibited greater pretreatment impairment in apparent diffusion coefficient (ADC) and blood flow measures, and were more likely to infarct by day 7.

Conclusions:

• Post-thrombolysis hyperperfusion is detectable with perfusion MRI in humans, occurring in a significant portion of patients.
• Hyperperfusion predominantly develops in brain areas that subsequently infarct, suggesting a link to severe ischemic injury.
• Pretreatment imaging markers indicate that tissues destined for hyperperfusion experience profound bioenergetic compromise.