Potential of dual-layer spectral CT for the differentiation between hemorrhage and iodinated contrast medium in the brain after endovascular treatment of ischemic stroke patients

Abstract

Background: One possible complication after mechanical thrombectomy is hemorrhage. In conventional CT it is often difficult to differ between extravasation of iodinated contrast medium and blood. This differentiation, however, is essential for treatments with anticoagulants and antiplatelets.

Purpose: To evaluate dual-layer spectral Computed Tomography (DLSCT) for the differentiation between intracranial hemorrhage and iodinated contrast medium in ischemic stroke patients after mechanical thrombectomy.

Materials and methods: First, in vitro experiments were performed. Then, head CT images of 47 patients after mechanical thrombectomy were analyzed. Virtual non-contrast (VNC) images and iodine density maps (IDM) were calculated and evaluated. Region of interests (ROIs) analyses were performed. Sensitivity and specificity as well as ROC curves were calculated.

Results: IDM and VNC images enabled clear differentiation between blood and iodine and reliable quantification of different iodine concentrations in vitro. A total of 23 hyperdense areas were detected in 13 patients, classified as hemorrhage (n = 7), iodinated contrast medium (n = 4) and a mixture of both (n = 12). Sensitivity and specificity for the detection of blood was 100%.

Conclusion: DLSCT enables differentiation between intracranial hemorrhage and iodinated contrast medium in patients after mechanical thrombectomy and might improve diagnostic imaging in post-interventional stroke patients.

Keywords: Contrast medium; Hemorrhage; Spectral computed tomography; Stroke.