Value of high-density sign on CT images after mechanical thrombectomy for large vessel occlusion in predicting hemorrhage and unfavorable outcome

Abstract

Purpose Cerebral hyperdensities can appear on head computed tomography (CT) images performed early after endovascular treatment (EVT) in patients with acute ischemic stroke and may be secondary to contrast staining or hemorrhagic transformation. The aim of this study was to determine how the high-density sign on CT affects mortality and clinical outcome and whether CT parameters predict hemorrhagic conversion or unfavorable outcome. Methods We retrospectively reviewed a database of patients who underwent EVT with mechanical thrombectomy for acute ischemic stroke over 7 years. Included were acute stroke patients with a CT examination within 24 h post-EVT with mechanical thrombectomy, demonstrating areas of hyperdensity. We evaluated morphologic characteristics of these lesions, location, CT Hounsfield units and largest area, as well as patient demographics, EVT methods and patient outcome. Results A total of 29 patients met the strict inclusion criteria. Complete recanalization was achieved in 58.6% (17/29). Seventeen (58.6%) cases of post-intervention cerebral hyperdensities were related to contrast staining and 12 (41.4%) cases to contrast staining and hemorrhage. Patient mortality was significantly higher in the hemorrhagic group (50.0% versus 5.9%, p = 0.003). The increased density on CT was associated with higher hemorrhagic risk (odds ratio 1.05, p = 0.036). Conclusion Patients with the high-density sign on CT images after mechanical thrombectomy for acute ischemic stroke demonstrated increased mortality and worse clinical outcome, primarily when these hyperdensities were related to hemorrhage. CT imaging parameters as higher density areas can help in the differentiation of hemorrhage from contrast staining.

Contrast enhancement by location and volume is associated with long-term outcome after thrombectomy in acute ischemic stroke

“…Some studies found that the presence of a high-density lesion on NCCT had no prognostic value to clinical outcome 8 – 10 . In contrast, Portela et al 3 found that the total size of the hyperdense area had a positive correlation with 90-day mRS after EVT. As previously reported, the hyperdensity may be related to the contrast agent, hemorrhagic transformation or a combination 9 , 11 , 13 , 17 , which may be caused by varying degrees of BBB disruption.…”

“…CE has been commonly found on the NCCT obtained immediately after EVT in patients with AIS 3 – 10 , which has been attributed to the disruption of the blood brain barrier 4 , 11 – 13 . In the present study, the incidence of CE on NCCT was 71.5%, which was comparable to prior reports (30.7–87.5% 3 – 10 ).…”

“…CE has been commonly found on the NCCT obtained immediately after EVT in patients with AIS 3 – 10 , which has been attributed to the disruption of the blood brain barrier 4 , 11 – 13 . In the present study, the incidence of CE on NCCT was 71.5%, which was comparable to prior reports (30.7–87.5% 3 – 10 ). Our work is novel in that we adapted the methodology of ASPECTS score to CE combined with volume measurement to assess the extent and location of CE, and found that CE based on this quantitative method after EVT was an independent and strong predictor of clinical functional outcome after excluding definite hemorrhage by 24-h follow up CT.…”

“…Some studies have reported that the presence of CE was a risk factor of functional outcomes 3 – 5 , while others did not find prognostic value 8 – 10 . We argue that the controversial results may be due to heterogeneous definitions of hyperdensity, the different computed tomography equipment used after EVT, or the lack of quantitative assessment of CE.…”

“…Endovascular thrombectomy (EVT) is recognized to be an effective therapeutic strategy to restore blood flow in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) 1 , 2 . Contrast enhancement (CE), defined as a visually distinct hyper-density on non-contrast computed tomography (NCCT) obtained immediately after the procedure, is commonly found with a reported incidence of 30.7–87.5% 3 – 10 . CE is believed to be due to disruption of the blood brain barrier (BBB) 4 , 11 – 13 , resulting in extravascular leakage of contrast medium, some of which may be mixed with extravascular blood.…”