Ghost infarct core following endovascular reperfusion: A risk for computed tomography perfusion misguided selection in stroke

Abstract

Background Computed tomography perfusion (CTP) has been increasingly used for patient selection in mechanical thrombectomy for stroke. However, previous studies suggested that CTP might overestimate the infarct size. The term ghost infarct core (GIC) has been used to describe an overestimation of the final infarct volumes by pre-treatment CTP of >10 ml. Aim We sought to study the frequency and predictors of GIC. Methods A prospectively collected mechanical thrombectomy database at a comprehensive stroke center between September 2010 and August 2020 was reviewed. Patients were included if they had a successful reperfusion (mTICI2b-3), a pre-procedure CTP, and final infarct volume measured on follow-up magnetic resonance imaging. Uni- and multivariable analyses were performed to identify predictors of GIC. Results Among 923 eligible patients (median [IQR] age, 64 [55–75] years; NIHSS, 16 [11–21]; onset to reperfusion time, 436.5 [286–744.5] min), GIC was identified in 77 (8.3%) of the overall patients and in 14% (47/335) of those reperfused within 6 h of symptom onset. The median overestimation volume was 23.2 [16.4–38.3] mL. GIC was associated with higher NIHSS score, larger areas of infarct core and tissue at risk on CTP, unfavorable collateral scores, and shorter times from onset to image acquisition and to reperfusion as compared to non-GIC. Patients with GIC had smaller median final infarct volumes (10.7 vs. 27.1 ml, p < 0.001), higher chances of functional independence (76.2% vs. 55.5%, adjusted odds ratio (aOR) 3.829, 95% CI [1.505–9.737], p = 0.005), lower disability (one-point-mRS improvement, aOR 1.761, 95% CI [1.044–2.981], p = 0.03), and lower mortality (6.3% vs. 15%, aOR 0.119, 95% CI [0.014–0.984], p = 0.048) at 90 days. On multivariable analysis, time from onset to reperfusion ≤6 h (OR 3.184, 95% CI [1.743–5.815], p < 0.001), poor collaterals (OR 2.688, 95% CI [1.466–4.931], p = 0.001), and higher NIHSS score (OR 1.060, 95% CI [1.010–1.113], p = 0.018) were independent predictors of GIC. Conclusion GIC is a relatively common entity, particularly in patients with poor collateral status, higher baseline NIHSS score, and early presentation, and is associated with more favorable outcomes. Patients should not be excluded from reperfusion therapies on the sole basis of CTP findings, especially in the early window.

Accuracy of CT Perfusion–Based Core Estimation of Follow-up Infarction

“…Our results are compatible with prior studies that suggested that ischemic core thresholds may be time-dependent [22][23][24] and stricter core thresholds should be used for patients who received perfusion imaging very early after symptom onset. 25 Ischemic core overestimation is a potential concern that has been controversial in the stroke community, with recent articles 14,21,26 suggesting that patients may be excluded from receiving EVT based on CTP overestimation of irreversible injury. The purpose of this study was to evaluate whether infarct core overestimation is frequent with the currently established rCBF <30% threshold, the effect of time from LKW and time from imaging to successful reperfusion on the incidence of potential overestimation, and whether the core overestimation can be eliminated with a more stringent rCBF <20% threshold.…”

CT Brain Perfusion in the Prediction of Final Infarct Volume: A Prospective Study of Different Software Settings for Acute Ischemic Core Calculation

“…Overestimation of the FIV on initial CTP, especially in patients with a short time window from LKW to CTP, has been proven in some recent studies [ 15 , 20 , 21 , 22 , 23 ]. The term ghost infarct core (GIC) was established for this phenomenon and it is considered to be one of the greatest limitations of CTP, which could lead to the erroneous exclusion of some patients from causative treatment, which is in the case of LVO EVT [ 18 , 20 , 21 , 24 ].…”

Core overestimation of CT perfusion in patients with cardiac insufficiency who had a stroke is mediated by impaired collaterals

“…However, over the past few years, the accuracy of CTP for core estimation has been challenged owing to continuous improvements in both the quality and speed of reperfusion treatments. Recent publications suggest that the use of the CTP-cerebral blood flow (CBF) technique may overestimate the infarct core volume in the very early window when fast and complete reperfusion is achieved 7 8. Collaterals are considered the key elements that set the pace of the ischemic process, and patients with failing collaterals may have rapid infarct growth and a larger hypoperfusion volume at admission 9 10.…”