Ct-Perfusion Absolute Ghost Infarct Core Is a Rare Phenomenon Associated with Poor Collateral Status in Acute Ischemic Stroke Patients

Abstract

Background: CT perfusion (CTP) overestimation of core volume >10 mL compared to the final infarct volume (FIV) size is the current definition of the ghost infarct core (GIC) phenomenon. However, subsequent infarct growth might influence FIV. We aimed to report a more reliable assessment of GIC occurrence, defined as no evidence of infarct at 24 h follow-up imaging, compared to CTP core volume at admission. This phenomenon was named absolute GIC (aGIC), and we investigated its prevalence and predictors. Methods: A total of 652 consecutive stroke patients with large vessel occlusion who achieved successful recanalization (mTICI 2b-3) after endovascular treatment (EVT) and non-contrast CT (NCCT) follow-up imaging at 24 h were retrospectively analyzed. Ischemic core volume was automatically generated from CTP, and FIV was manually determined on follow-up NCCT. Multivariable logistic regression was used to explore aGIC predictors. Results: We included 652 patients (53.3% female, median age 75 years), of whom 35 (5.3%) had an aGIC. The aGIC group showed higher ASPECTS (p < 0.001), shorter (<3 h) onset-to-imaging time (p < 0.016), poorer collaterals (p < 0.001), and higher hypoperfusion intensity ratio (p < 0.001) compared to the non-aGIC group. In multivariate analysis, ASPECTS (odds ratio (OR), 2.37; p <0.001), onset-to-imaging time (OR, 0.99; p = 0.034), collateral score (OR, 0.24; p < 0.001), and hypoperfusion intensity ratio (OR, 23.2; p < 0.001) were independently associated with aGIC. Conclusions: aGIC is a more reliable evaluation of infarct core volume overestimation assessed on admission CTP and represents a rare phenomenon, associated with ultra-early presentation and poor collaterals.

Keywords: CT perfusion; absolute ghost infarct core; acute ischemic stroke; collaterals; endovascular treatment; large vessel occlusion.

Figure 1

Flowchart of study population selection.

Figure 2

Illustrative case of absolute ghost infarct core (aGIC). A 64-year-old patient with acute ischemic stroke (AIS) suffering from the occlusion of left M1 segment of middle cerebral artery (MCA), which occurred within 3 h of stroke onset. (A) No visible hypodensity on non-contrast computed tomography (NCCT) resulted in ASPECTS = 10 with (B) poor multi-phase CT–angiography collaterals (Menon score = 2). CT perfusion shows the presence of 14.5 mL of core volume and 83.6 mL of penumbra volume in left hemisphere (C) and high hypoperfusion intensity ratio (HIR) = 0.7 (D). After successful recanalization, follow-up NCCT performed at 24 h (E) revealed no evidence of hypoattenuated areas, indicating the absence of final infarct volume.