Is limited-coverage CT perfusion helpful in treatment decision-making in patients with acute ischemic stroke?

Abstract

Background: The initial core infarct volume predicts treatment outcome in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). According to the literature, CT perfusion (CTP) is able to evaluate cerebral parenchymal viability and assess the initial core in AIS. We prospectively studied whether limited-coverage CTP with automated core calculation correlates with the final infarct volume on follow-up non-enhanced CT (NECT) in patients successfully treated by mechanical thrombectomy.Methods: We enrolled 31 stroke patients (20 women aged 74.4±12.9 years and 11 men aged 66±15.4 years; median initial NIHSS score 15.5) with occlusion of the medial cerebral artery and/or the internal carotid artery that were treated by successful mechanical thrombectomy. CTP performed in a 38.6 mm slab at the level of basal ganglia was included in the CT stroke protocol, but was not used to determine indication for mechanical thrombectomy. The infarction core volume based on CTP was automatically calculated using dedicated software with a threshold defined as cerebral blood flow <30% of the value in the contralateral healthy hemisphere. The final infarction volume was measured on 24-hour follow-up NECT in the same slab with respect to CTP. Pearson and Spearman correlation coefficients and robust linear regression were used for comparison of both volumes, P values <0.05 were considered as statistically significant.Results: The median time from stroke onset to CT was 77 minutes (range, 31-284 minutes), and the median time from CT to vessel recanalization was 95 minutes (range, 55-215 minutes). The mean CTPcalculated core infarct volume was 24.3±19.2 mL (median 19 mL, range 1-79 mL), while the mean final infarct volume was 21.5±39.5 mL (median 8 mL; range 0-210 mL). Only a weak relationship was found between the CTP-calculated core and final infarct volume [Pr (29) =0.32, P=0.078; rho =0.40, P=0.028].Regression analysis showed CTP significantly overestimated lower volumes.Conclusions: In our prospective study, the infarction core calculated using limited-coverage CTP only weakly correlated with the final infarction volume measured on 24-hour follow-up NECT; moreover, CTP significantly overestimated lower volumes. Our results do not support the use of limited-coverage CTP for guiding treatment recommendations in patients with AIS.

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 ].…”

“…We have been studying diagnostic and therapeutic possibilities in AIS patients for several years [ 15 , 16 , 17 ]. In the present study, we evaluated the accuracy of three different syngo.via settings in the estimation of the acute ischemic core on CTP.…”

Diagnosis of Ischemic Stroke: As Simple as Possible

“…However, the DAWN and DEFUSE 3 trials figuratively resuscitated CTP, as they used CTP-calculated penumbra volume as a predictive factor for clinical outcome in patients treated with EVT in the late time window [ 10 , 11 ]. However, as was mentioned above, there is evidence that the ischemic core on CTP poorly correlates with the definitive ischemic volume in patients with AIS with LVO after successful urgent EVT, at least in the time window up to 6 h from AIS onset [ 43 , 45 , 46 ]. Moreover, some authors have reported significant overestimation of initial core volume on CTP, which was romantically called a “ghost infarct” ( Figure 4 ) [ 47 , 48 ].…”

Thin-slab maximum intensity projection of CT angiography for collateral score and clot burden score evaluation: comparison with conventional CT angiography

“…The flowchart in Figure 1 outlines the process used for inclusion and exclusion of patients. Baseline median admission National Institutes of Health Stroke Scale (NIHSS) score was 14 (IQR, [10][11][12][13][14][15][16][17][18]. Mean admission systolic blood pressure was 145.5±19.5 mmHg.…”

“…However, it is difficult to quantify collateral supply due to its diminutive and complex routes. As we all know, CTA can be used to screen acute ischemic stroke for determining the occlusion site (15), and it can also provide a simple and reproducible assessment method for collateral supply evaluation to confirm the association between collateral supply and clinical outcome. Up to now, several CTAbased collateral grading systems have been proposed for patients with acute LVO strokes, including the ASITN/SIR, ASPECTS, Christoforidis and Miteff collateral grading systems (13,(16)(17)(18), however, there is no consensus on which one is the best.…”