Imaging options, advantages, and limitations at primary stroke centers
| Imaging Modality | Pros | Cons |
|---|---|---|
| Plain CT only | Highly time-efficient | Detection of LVO is not reliable. |
| Dense MCA sign is not reliable20 | ||
| Variability in ASPECTS reading, especially in the very early time window21 | ||
| CT plus single-phase CTA (arch to vertex) | Exact occlusion site Basic assessment of collaterals | Considerable risk of collateral underestimation if acquisition timed too early |
| Roadmap for EVT procedure | Distal occlusions might be missed; challenges with training and maintaining competence for technologists in low-volume community settings | |
| CT plus multiphase CTA | Robust collateral assessment (independent of timing) | Collateral assessment may require training |
| Diagnosis of LVO in inexperienced readers | ||
| Easier detection of distal occlusions7 | ||
| No additional contrast needed | ||
| Can be done on any modern scanner | ||
| CT plus CTP | Easier identification of patients eligible for EVT | More sensitive to patient motion |
| Easier identification of stroke mimics in the absence of LVO22 | Time-consuming; may create a bottleneck in a workflow wherein the paramedic team that brings the patient in is the same team that takes the patient to the CSC | |
| Limited comparability of CTP results across protocols and postprocessing software23,24 | ||
| Higher contrast and radiation dose needed | ||
| CTP pitfalls25 | ||
| Cost of additional postprocessing software, optional |