Value Of Dual-energy CT For Early Diagnosis And Prediction Of Intracranial Hemorrhage After Stent Thrombectomy For Acute Ischemic Stroke

Objective:Intracranial hemorrhage is one of the most common and serious complications in patients with acute ischemic stroke after mechanical thrombectomy,which may affect patients’ treatment and prognosis.The aim of our study was to assess the value of dual-energy CT(DECT)in early diagnosis of the intracranial hemorrhage and the risk prediction of hemorrhagic transformation/increased bleeding in patients with acute ischemic stroke after thrombectomy with Solitaire stent.Methods:Patients with acute ischemic stroke who had undergone thrombectomy with Solitaire stent and DECT within 1 hour were collected.In this method,the concentration of370mg/ml iodinated contrast agent was being adopted.After the reconstruction,linear fusion images,virtual plain scans and iodine maps were obtained.The diagnosis was confirmed by comprehensive analysis.Routine CT scan was performed as the standard of making a definite diagnosis at 24 hours postoperatively.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of early diagnosis for intracranial hemorrhage with DECT were respectively evaluated.The iodine concentration of intracranial lesions was measured on the iodine map.The follow-up results were used as standard data.The receiver operating characteristic(ROC)analysis was used to obtain the threshold of hemorrhagic transformation or increased bleeding,and the specificity,accuracy and area under the curve were evaluated.Results:Forty-four patients were enrolled.Among them there were 25 cases with purely iodinated contrast agent extravasation for DECT comprehensive analysis and diagnosis,19 cases with combined intracranial hemorrhage.It has been proven that patient with DECT diagnosed for iodinated contrast agent extravasation will occur intracranial hemorrhage,23 remaining proven to be correct in diagnose.Those 19 cases with iodinated contrast agent extravasation combined intracranial hemorrhage were correctly diagnosed.Compared with 24 hour postoperative follow-up CT,the early diagnosis postoperative intracranial hemorrhage with DECT had 90.5% sensitivity,100% specificity,100% positive predictive rate,92.0% negative predictive rate and 95.5% accuracy,respectively.Eighty-sixintracranial lesions were measured for iodine concentration.During follow up,19 lesions showed hemorrhagic transformation/increased bleeding,with the average iodinated concentration of(3.5±1.6)mg/ml,67 lesions without hemorrhagic transformation/increased bleeding,with the average iodinated concentration of(3.5±1.6)mg/ml.The difference between the two groups was enormous,which is the high iodinated extravasation area was easily occurring the bleeding transformation and increase.Two groups in the ROC analysis marks 2.7 mg/ml cut-off value,and the DECT estimates that the after the thrombectomy with Solitaire stent,the sensitivity and specificity for bleeding transformation and increase were 73.7% and 92.5%,respectively.Conclusion:DECT plays an important role in the early diagnosis and prediction of intracranial hemorrhage after stent thrombectomy in acute ischemic stroke.