TICI

TICI, short for Thrombolysis in Cerebral Infarction, is a grading system used in neuroradiology to quantify the extent of cerebral reperfusion after endovascular therapy or thrombolysis for acute ischemic stroke. The scale assesses the degree of blood flow restoration within the ischemic cerebral territory and is commonly applied after mechanical thrombectomy or intra-arterial thrombolysis.

The original Thrombolysis in Cerebral Infarction scale ranges from 0 to 3: 0 indicates no measurable perfusion; 1 indicates penetration with minimal perfusion; 2a represents partial filling of less than half of the vascular territory; 2b indicates substantial filling of more than half but less than complete; and 3 denotes complete perfusion of the territory.

A modified version, the modified TICI (mTICI) scale, is widely used in contemporary practice. In addition to 0–3, it introduces 2c to describe near-complete perfusion with only slow flow or minor distal defects, while 3 remains complete perfusion. The mTICI scale is often favored in clinical trials and captures subtler distinctions in reperfusion quality.

Applications and interpretation: TICI/mTICI grades are reported after reperfusion therapy to gauge treatment success and are associated with patient outcomes. In many studies, achieving mTICI 2b or better is considered successful reperfusion and correlates with improved functional prognosis at follow-up. The exact threshold for favorable outcome can vary by trial and protocol.

Limitations include interobserver variability, dependency on the imaging modality and timing, and the fact that a high grade of reperfusion does not guarantee a good clinical outcome. The scale measures perfusion but not tissue viability or collateral status, and it should be interpreted alongside clinical and imaging data.