Dignostic Value And Investigation Of Double Energy Computed Tomography Angiography In Intracranial Aneurysms

ObjectiveTo explore the methods of dual-energy computed tomography angiography(DE-CTA) in the detection of intracranial aneurysms.To evaluate the value of dual-energy computed tomography angiography in the diagnosis of intracranial aneurysms.Materials and MethodsBetween April 2009 and April 2010,54 patients from the Heping Hospital of changzhi medical college were enrolled in this project. The patients included 31 females and 23 males ranging in age from 15 to 72 years,with an mean age of 48.2±15.7 years.All the patients were underwent CTA with dual-source CT and digital subtraction angiography (DSA).9 patients were performed operation.42 patients with intracranial aneurysms were detected by both digital subtraction angiography (DSA).The clinical manifestation:31 patients had initially presented with abrupt headache,9 patients with nausea and vomit,11 patients with coma, 7 patients with vertigo,2 with vision degression,3 patients with chronic intermittent headache from 2 to 6 months.34 patients accopaning with subarachnoid hemorrhage(SAH),3 patients with SAH history.3 patients with intracranial haematoma.The patients were individually scanned from 3 hours to 6 months since falled ill.All cases were performed DSA within 1 week after DE-CTA.The patients were scanned by using DE-CTA with DSCT(Somatom Definition,Siemens Medical Systems,Germany).Patients were examined in supine position with submaxilla adducting,and head were fixed.Firstly,the site-specific image was obtained,and the scan range was selected in different orientations.Then enhanced DE-CTA mode was performed.The volume of nonionic iodinated contrast medium(Iopromide, Ultravist,370mgI/ml,Schering)were injected in opisthenar vein with a power injector(Ulrich Missouri, Ulrich Medical,Germany)at a rate of 4.2ml/s for a total of 85 milliliters,and 30 milliliters of saline flush was applied to maintain a compact bolus.Scan delay was adapted by using a bolus-tracking technique.Individual contrast timing was based on bolus tracking options of the scanner(CARE Bolus).Aortic arch was selected as Premonitioring,and the threshold was 110Hu.Scanning was started after a 4-second delay.The scan range included aortic arch up to the vertex. Scanning time was about 6s.The scanning parameters:Tube voltages were set to 140kV and 80kV for both tubes,effective current were adjusted to 49mA and 200mA,with 64×0.6mm acquisition slice width,with a 512×512 matrix.A reconstruction slice of 0.6mm,interval of 0.3mm. Gantry rotation time was 0.33s,pitch 0.65 adapted to the head.Extended field of view was 219mm.The total of scanning time was 10.13s.The data of 3 groups were transferred to a workstation(syngo CT 2008G)and automatically reconstructed,individually 140KV,80KV and composite ampho-data.The reconstruted images were processed into Volume Rendering(VR),Maximun Intensity Projection(MIP), Multiplanar Reconstruction(MPR),Curved Planar Reconstruction(CPR )for Visualizating intractanial aneurysms.Two radiologists interpreted CTA images to detect intracranial aneurysms and compared the effect of visualization between different reconstruction methods.If an aneurysm was detected,the relationship between the aneurysms predefined vessel locations for the presence of an aneurysm,and osseous surrounding structures were observed. Several morphologic characteristics were evaluated:the aneurysm maximal diameter(D) and neck(N) were measured. The diagnostic sensitivity and specificity of aneurysms were evalued compared with DSA and the finding of operations.The difference and correlation of the quantitative determination of aneurysms were compared between DE-CTA and DSA.Results1.Using enhanced DE-CTA mode,the scanned data of 54 patients were processed into reconstruction.Individually the data was 140KV,80KV and composite ampho-data.All kinds of excellent DE-CTA reconstructed imagings were gained including excellent bone elimination imagings.2.Using DSA and the finding of operations as the standard of reference,sensitivity and specificity of DE-CTA to detect intracranial aneurysms were 93.0% and 100% on a per-patient basis,91.8% and 100% on a per-aneurysm basis.3.Excellent correlation was found between DSA and DE-CTA in the quantitative diagnosis of intracranial aneurysms(r= 0.962,0.970,0.859,P<0.01)on the long,short axis and size of neck.There was no statistical difference between DE-CTA and DSA(t= 1.721,1.993,1.915,P>0.05).4.There was no statistical difference between the 4 processing methods of DE-CTA for visualizating intracranial aneurysms and adjacent structures(P>0.05).There were statistical difference between VR and MPR/CPR for visualizating osseous surrounding structures(P<0.01). The osseous surrounding structures could not displaied by using MIP.Conclusions1.There were higher diagnostic sensitivity and specificity for intracranial aneurysms by using DE-CTA technique. Excellent correlation was found between DSA and DE-CTA in the quantitative diagnosis of intracranial aneurysms.All kinds of excellent DE-CTA reconstructed imagings were gained simultaneously by using a single contrast-enhanced DE-CTA.The excellent bone elimination imagings were gained on energy subtraction principal basis.As an noninvasive and volant method,a single contrast-enhanced DE-CTA has higher achievement ratio for diagnosing intracranial aneurysms.2.The methods of VR were more integrative for visualizating osseous surrounding structures compared with the others.The methods of VR,MIP,MPR/CPR were excellent for visualizating aneurysmas and relationship between the aneurysms predefined vessel locations for the presence of an aneurysm.