Dual-energy CT in assessment of thrombus perviousness and its application in predicting outcomes after intravenous thrombolysis in acute ischemic stroke.

PURPOSE

To evaluate the feasibility of using iodine overlay maps reconstructed from dual-energy CT (DECT) to assess thrombus perviousness and investigate its value in predicting outcomes after intravenous thrombolysis in patients with acute ischemic stroke.

METHOD

86 patients with proximal intracranial occlusions of the anterior circulation who underwent intravenous thrombolysis were included in this study. Thrombus iodine concentrations (IC) and normalized iodine concentrations (NIC) were compared to conventional perviousness parameters (thrombus attenuation increase, TAI; void fraction, ε and CTA-index). The associations between perviousness parameters and outcomes were analyzed by Spearman's correlation and regression analysis.

RESULTS

IC and NIC were significantly correlated with conventional perviousness parameters (P < 0.001). The median IC was 6.81 (interquartile range [IQR], 4.76-8.73) mg/ml in the favorable functional outcome group, which was higher than 3.52 (IQR, 2.08-6.86) mg/ml in the unfavorable outcome group (P = 0.001). The median NIC was 0.095 (IQR, 0.068-0.116) and 0.054 (IQR, 0.031-0.083) in the favorable and unfavorable outcome groups, respectively (P < 0.001). NIC predicted favorable outcome with a higher area under the curve (AUC) of 0.755 than any conventional perviousness parameter (P < 0.05). In the multivariable regression model, IC was independently associated with favorable outcome (odds ratio [OR] = 1.472, 95 % CI: 1.154-1.877, P = 0.002) and successful recanalization (OR = 1.356, 95 % CI: 1.093-1.681, P = 0.006). IC was negatively correlated with the final infarct volume (FIV) (r = -0.262, P = 0.020). Results for NIC were similar.

CONCLUSIONS

DECT is of great value in assessing thrombus perviousness. NIC is a meaningful predictor of stroke prognosis and recanalization after intravenous thrombolysis in acute ischemic stroke.