mTICI

mTICI, or modified thrombolysis in cerebral infarction score, is a grading system used to quantify reperfusion of the ischemic brain tissue after endovascular treatment for acute ischemic stroke. It assesses the extent of perfusion restoration in the originally identified target vascular territory on angiographic imaging. The score ranges from 0 to 3: 0 indicates no perfusion; 1 penetration with minimal perfusion; 2a partial reperfusion of less than half of the vascular territory; 2b substantial reperfusion of more than half; 3 complete perfusion. Some definitions also include a 2c category to denote near-complete reperfusion with slow flow or only minor residual defects.

The mTICI score is determined by the interventional radiologist or neurointerventionalist during the procedure or on immediate post-procedure imaging. It is widely used in clinical trials and registries to evaluate the efficacy of reperfusion therapies, particularly mechanical thrombectomy, and to correlate reperfusion quality with functional outcomes measured by the modified Rankin Scale. Achieving mTICI 2b or 3 is generally associated with improved outcomes and lower rates of hemorrhagic transformation, though results depend on infarct size, collateral status, and time to reperfusion.

Limitations include interobserver variability, differences in imaging technique, and the score’s focus on angiographic perfusion rather than tissue viability. The mTICI score remains a standard metric in stroke interventional care but should be interpreted alongside clinical context and other imaging findings.