Relevance of Blood–Brain Barrier Disruption After Endovascular Treatment of Ischemic Stroke

Abstract

E ndovascular therapy (ET) is an increasingly used therapeutic strategy in acute ischemic stroke.1 The administration of contrast material during ET often results in high attenuation areas on postprocedural brain computed tomography (CT) related to blood-brain barrier (BBB) breakdown, although their clinical significance is conflicting.2-8 Early differentiation between contrast enhancement and brain hemorrhage may be of assistance to detect bleeding complications and anticipate the start of antithrombotic therapy after thrombolysis. 9 However, in the early post-ET period, this distinction is not feasible using conventional post-treatment CT. [2][3][4][5]10 Dual-energy CT (DE-CT) is a relatively new technique that allows for a reliable differentiation between tissue high attenuation areas related to iodine contrast material extravasation and parenchymal hemorrhage.11-13 The technique is based on the different attenuation effects of normal brain tissue, iodine, and blood at different irradiation energy levels. In patients receiving ET, DE-CT has shown a good accuracy for early differentiation between hemorrhage and contrast extravasation, but these studies did not address specifically the prognostic implications of this segregation. 12,14,15 Brain ischemia induces time-dependent changes in microvascular integrity and these changes may lead to the extravasation of contrast molecules and cellular blood elements from microvessels leading to hemorrhagic complications. 16,17 Thus, the ability of DE-CT to differentiate between contrast and brain hemorrhage after ET may allow discriminating between different grades BBB disruption. The aim of the study was to evaluate the prognostic significance of the presence of contrast Background and Purpose-Computed tomographic (CT) high attenuation (HA) areas after endovascular therapy for acute ischemic stroke are a common finding indicative of blood-brain barrier disruption. Dual-energy CT allows an accurate differentiation between HA areas related to contrast staining (CS) or to brain hemorrhage (BH). We sought to evaluate the prognostic significance of the presence of CS and BH after endovascular therapy. Methods-A prospective cohort of 132 patients treated with endovascular therapy was analyzed. According to dual-energy CT findings, patients were classified into 3 groups: no HA areas (n=53), CS (n=32), and BH (n=47). The rate of new hemorrhagic transformations was recorded at follow-up neuroimaging. Clinical outcome was evaluated at 90 days with the modified Rankin Scale (poor outcome, 3-6). Results-Poor outcome was associated with the presence of CS (odds ratio [OR], 11.3; 95% confidence interval, and BH (OR, 10.4; 95% confidence interval,

Response to Letter Regarding Article, “Relevance of Blood–Brain Barrier Disruption After Endovascular Treatment of Ischemic Stroke: Dual-Energy Computed Tomographic Study”

“…2 We fully agree that a new therapeutic approach using a combination of rapid reperfusion and neuroprotective/vasculoprotective therapies would be of added value for further improving clinical outcome in comparison with rapid reperfusion alone. Indeed, several clinical trials of patients treated with mechanical thrombectomy have recently shown that this therapy is superior to best medical treatment in selected patients with proximal arterial occlusions but also highlighted that despite a high recanalization rate, less than half of the patients allocated to endovascular therapy showed a good functional outcome at follow-up.…”

Immunomodulation after ischemic stroke: potential mechanisms and implications for therapy

“…Stroke disrupts the blood–brain barrier (BBB), increasing its permeability and the entry of immune cells [10]. Within 24 h after stroke onset, macrophages enter the brain, but their role in infarct development is controversial.…”

MRI Appearance of Intracerebral Iodinated Contrast Agents: Is It Possible to Distinguish Extravasated Contrast Agent from Hemorrhage?

“…2 Recent studies dealing with dual-energy CT imply that it is possible to distinguish contrast extravasation from hemorrhage by using this method. 1,3 However, the limited availability of these scanners remains a relevant hurdle in daily clinical practice. In most institutions, MR imaging may be the technique of choice because it is widely available and hemorrhage causes specific signal changes on MR imaging.…”

“…There is uncertainty about the true nature of postinterventional cerebral hyperattenuation, specifically the extent to which postinterventional cerebral hyperattenuations correspond to hemorrhage or extravasation of iodinated contrast agent into infarcted parenchyma. [1][2][3][4] In theory, hemorrhage can be distinguished from iodinated contrast agents via MR imaging, given that blood degradation products are paramagnetic and cause specific changes on T2WI and T2 * WI, whereas iodine is diamagnetic. However, it has been shown in phantom models that at a field strength of 1.5T, side chains of iodinated contrast agents cause T1 and T2 shortening, which theoretically may mimic the imaging characteristics of intracellular methemoglobin present in early subacute intracerebral hemorrhage.…”