RadteraCT Brain Perfusion (Stroke)
CT+ ContrastNeuroverify
Indications
- Acute ischemic stroke triage / large vessel occlusion (LVO) selection for thrombectomy
- Identification of ischemic core vs salvageable penumbra (mismatch) in extended/late window (6-24 h, DAWN/DEFUSE-3 criteria)
- Evaluation of cerebral hemodynamics (e.g., vasospasm after SAH, chronic steno-occlusive disease)
Patient prep
- Typically emergent; renal function not required to delay in acute stroke per ACR
- 18-20G IV in antecubital vein for power injection
- Coordinate with non-contrast CT head and CTA head/neck as a single stroke protocol package
- Remove metal/hairpins from head
Contrast
Agentiodinated (iohexol 350 or iopamidol 370)
RouteIV
Dose35-50 mL at 4-6 mL/s, followed by 20-40 mL saline chase
TimingDynamic cine acquisition begun ~3-5 s after injection; total acquisition 45-70 s to capture arterial inflow through venous washout
Technique
- Supine, head in head holder, gantry parallel to skull base
- Z-axis coverage 80-160 mm depending on detector width (wide-detector 256/320 covers whole brain; narrower scanners use toggling/shuttle)
- Low kV (70-80 kV) to maximize iodine contrast and reduce dose; 100-250 mAs per pass
- Dynamic/cine mode, ~25-35 passes, ~1-3 s temporal sampling
- Post-process on automated software (RAPID, vendor perfusion package) for CBF, CBV, MTT, Tmax maps
- Done after non-contrast head; usually before or interleaved with CTA
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Source dynamic axial | axial | 5-10 mm (reconstructed) | Cine source data for deconvolution |
| 2 | CBF map | axial | color map | Core = CBF <30% of normal |
| 3 | CBV map | axial | color map | Core surrogate |
| 4 | MTT map | axial | color map | Prolonged in ischemia |
| 5 | Tmax map | axial | color map | Penumbra = Tmax >6 s; mismatch volume/ratio reported |
Key points
- Core = relative CBF <30%; penumbra (at-risk) = Tmax >6 s; mismatch ratio and volumes drive thrombectomy decisions
- Motion is the main pitfall; immobilize and coach patient
- Truncation of the time-density curve (acquisition too short) overestimates core; ensure adequate venous-phase sampling
- Use low kV and automated dose modulation; perfusion is the highest-dose component of the stroke workup
- Whole-brain coverage preferred to avoid missing posterior fossa/border-zone ischemia
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.