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Overestimation of ischemic core on baseline MRI in acute stroke
M A McArthur1, E Tavakkol1, M Bahr-Hosseini2
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, USA.
Abstract:
Background and PurposeIn patients with acute ischemic stroke (AIS), overestimation of ischemic core on MRI-DWI has been described primarily in regions with milder reduced diffusion. We aimed to assess the possibility of ischemic core overestimation on pretreatment MRI despite using more restricted reduced diffusion (apparent diffusion coefficient (ADC) ≤620 × 10-6 mm2/s) in AIS patients with successful reperfusion.Materials and MethodsIn this retrospective single institutional study, AIS patients who had pretreatment MRI underwent successful reperfusion and had follow-up MRI to determine the final infarct volume were reviewed. Pretreatment ischemic core and final infarction volumes were calculated. Ghost core was defined as overestimation of final infarct volume by baseline MRI of >10 mL. Baseline clinical, demographic, and treatment-related factors in this cohort were reviewed.ResultsA total of 6/156 (3.8%) patients had overestimated ischemic core volume on baseline MRI, with mean overestimation of 65.6 mL. Three out of six patients had pretreatment ischemic core estimation of >70 mL, while the final infarct volume was <70 mL. All six patients had last known well-to-imaging <120 min, median (IQR): 65 (53-81) minutes.ConclusionsOverestimation of ischemic core, known as ghost core, is rare using severe ADC threshold (≤620 × 10-6 mm2/s), but it does occur in nearly 1 of every 25 patients, confined to hyperacute patients imaged within 120 min of symptom onset. Awareness of this phenomenon carries implications for treatment and trial enrollment.
Insights
Ghost core, or overestimated ischemic core on MRI, is rare in acute ischemic stroke (AIS) patients using a strict diffusion threshold. However, it occurs in nearly 4% of hyperacute patients, impacting treatment decisions.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Overestimation of ischemic core on MRI-DWI in acute ischemic stroke (AIS) is primarily observed in areas with less severe diffusion reduction.
- This study investigates ischemic core overestimation using a restricted diffusion threshold in AIS patients with successful reperfusion.
Purpose of the Study:
- To assess the possibility of ischemic core overestimation on pretreatment MRI in AIS patients, even when using a restricted apparent diffusion coefficient (ADC) threshold (≤620 × 10-6 mm2/s).
- To identify the incidence and characteristics of "ghost core" (overestimated ischemic core) in AIS patients who achieved successful reperfusion.
Main Methods:
- Retrospective analysis of AIS patients with pretreatment MRI, successful reperfusion, and follow-up MRI to determine final infarct volume.
- Calculation of pretreatment ischemic core and final infarct volumes, defining "ghost core" as an overestimation of >10 mL.
- Review of baseline clinical, demographic, and treatment-related factors.
Main Results:
- A total of 6 out of 156 (3.8%) patients exhibited overestimated ischemic core volume (ghost core) on baseline MRI, with a mean overestimation of 65.6 mL.
- Three patients had a pretreatment core estimation >70 mL, while their final infarct volume was <70 mL.
- All six patients with ghost core were imaged within 120 minutes of symptom onset (median: 65 minutes).
Conclusions:
- Ghost core, or ischemic core overestimation, is rare but occurs in approximately 1 in 25 hyperacute AIS patients when using a severe ADC threshold (≤620 × 10-6 mm2/s).
- This phenomenon is confined to patients imaged within 120 minutes of symptom onset.
- Awareness of ghost core is crucial for accurate treatment decisions and clinical trial enrollment in AIS management.
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