Computed tomography perfusion as an early predictor of malignant cerebral infarction

Abstract

Introduction: Malignant middle cerebral artery infarction (MCI) needs rapid intervention. This study aimed to enhance the prediction of MCI using computed tomography perfusion (CTP) with varied quantitative benchmarks.

Materials and methods: We retrospectively analyzed 253 patients from a single-center registry presenting with acute, severe, proximal large vessel occlusion studied with whole-brain CTP imaging at hospital arrival within the first 24 h of symptoms-onset. MCI was defined by clinical and imaging criteria, including decreased level of consciousness, anisocoria, death due to cerebral edema, or need for decompressive craniectomy, together with midline shift ⩾6 mm, or infarction of more than 50% of the MCA territory. The predictive accuracy of baseline ASPECTS and CTP quantifications for MCI was assessed by receiver operating characteristic (ROC) area under the curve (AUC) while F-score was calculated as an indicator of precision and sensitivity.

Results: Sixty-three out of 253 patients (25%) fulfilled MCI criteria and had worse clinical and imaging results than the non-MCI group. The capacity to predict MCI was lower for baseline ASPECTS (AUC 0.83, F-score 0.52, Youden's index 6), than with perfusion-based measures: relative cerebral blood volume threshold <40% (AUC 0.87, F-score 0.71, Youden's index 34 mL) or relative cerebral blood flow threshold <35% (AUC 0.87, F-score 0.62, Youden's index 67 mL). CTP based on rCBV measurements identified twice as many MCI as baseline CT ASPECTS.

Discussion and conclusion: CTP-based quantifications may offer enhanced predictive capabilities for MCI compared to non-contrast baseline CT ASPECTS, potentially improving the monitoring of severe ischemic stroke patients at risk of life-threatening edema and its treatment.

Keywords: Computed tomography perfusion; acute stroke; brain edema; malignant cerebral infarction.

Graphical abstract

Figure 1.

Non-contrast CT scan (a), rCBF (b), and rCBV (c) maps of a 63-year-old man with an acute stroke due to an occlusion of the M1 segment of the right middle cerebral artery. Complete recanalization was obtained with mechanical thrombectomy. CT performed 24 h later (d) showed malignant cerebral edema with 12 mm midline shift. Non-contrast CT scan (e), rCBF (f), and rCBV (g) maps of a 60-year-old female with an acute stroke due to right MCA M1 occlusion and complete recanalization after mechanical thrombectomy. CT performed 24 h later (h) showed mild edema without a midline shift. Note the difference in the perfusion maps, with a greater decrease in CBF and, especially, CBV in the first case, that developed malignant cerebral infarction.

Figure 2.

Flow chart of the patients included in the study.

Figure 3.

Heatmap summarizing the predictive performance of ASPECTS and several perfusion-based metrics ordered by decreasing F1-scores. rCBF: relative cerebral blood flow; rCBV: relative cerebral blood volume.

Figure 4.

Diagram of the distribution of true positives, false negatives, false positives, and true negatives using ASPECTS cut-off values <6 and CTP rCBV 40% >34 mL. Considering the 25% prevalence of MCI in our study cohort, ASPECTS identified 8 true positives, with 17 false negatives and 5 false positives. The rCBF cut-off identified 16 true positives, with 9 false negatives, and 8 false positives.

Figure 5.

ROC curve of ASPECTS and CT-perfusion rCBV 40% in the whole cohort, patients who underwent mechanical thrombectomy and patients not treated with mechanical thrombectomy.