Table 1.

Stroke imaging modalities

Imaging method	Current use in clinical routine	Iodinating radiation	Revascularization vs. reperfusion component	Advantages	Disadvantages	Likelihood of being used for routine post-EVT reperfusion assessment
CT perfusion	Pre-EVT assessment of core and penumbra	+ + +	Substantial revascularization component (purely intravascular contrast agent), intravenous injection	• Widely available • Different parameters • Can be performed on the angio table if hybrid or flat-panel angio suite is available	• Substantial increase in radiation dose • Post-processing necessary • Prone to motion and technical artifacts	Very low
Multiphase CT angiography	Pre-EVT assessment of collateral circulation (helps to estimate core and penumbra)	+	Substantial revascularization component (purely intravascular contrast agent), intravenous injection	• Even more widely available • No need for post-processing • Robust against motion and technical artifacts • Can be performed on the angio table if hybrid or flat-panel angio suite is available	• Slight increase in radiation dose • Less precise (fewer time points) compared to CTP	Very low
Diffusion-weighted MRI and MRP	24-h post-EVT infarct assessment (in some centers also used for pre-EVT assessment)	None	Primarily reperfusion (DWI: cytotoxic edema, represents severe hypoperfusion/infarction, no contrast agent required; MRP: MR contrast agents can leave the intravascular compartment to some extent, intravenous injection)	• No substantial recanalization component (as opposed to all other routinely used imaging methods) • Radiation-free • Additional MR sequences can be performed to gain information about other post-recanalization tissue damage mechanisms	• Less available • Expensive • Contraindications (pacemaker etc.) • Prone to motion artifacts • Patient needs to be transferred from the angio table to the MR scanner	High
DSA perfusion	Not in clinical use yet	None (no additional radiation)	Substantial revascularization component (purely intravascular contrast agent), intra-arterial injection	• Routine intra-arterial injection can be used to generate DSAP maps (no additional steps needed)	• Imaging is obtained on the angio table (no need to transfer the patient)	Unclear

Different imaging modalities that can potentially be used to measure reperfusion post-recanalization/EVT

CTP CT perfusion, MRP MR perfusion, DSAP digital subtraction angiography perfusion, DWI diffusion-weighted imaging, EVT endovascular treatment