Clinical Evaluation Of Dual-energy CT Cerebral Angiography In Diagnosis Of Intracranial Aneurysm

ObjectiveTo assess clinical value of dual-energy CT angiography in diagnosis of intracranial aneurysm.Materials and MethodsBetween May 2008 and October 2009,Seventy-two patients suspected with intracranial aneurysm were performed on a dual-source CT in dual energy mode.The Patients included 32 females and 40 males ranging age from 21—76 years,with a mean age of 48±11 years. All the patients underwent CTA with dual-source CT.49 patients were performed digital subtraction angiography(DSA).11 patients were performed DSA and operations.7 patients were performed operations.All the patients were scanned by using DE-CTA with DSCT(Somatom Definition, Siemens Medical Systems, Germany).Patients were examined in supine position,with their heads fixed. Firstly,the scout view image was obtained.The scan range was from lower jawbone to calvarium. Then the volume of nonionic iodinated contrast medium(Omnipaque,350mgI/ml).were injected via opisthenar vein with a power injector at a rate of 3.5-4ml/s for a total of 70-80ml,followed by a 30ml saline flush at the same rate.The delay time of the CT data acquisition after the injection was determined using a bolus tracking software located the basilar artery or internal carotid artery(ICA).The raw data were obtained and transferred to the workstation (Leonardo, Siemens Medical Solutions) for postprocessing, combined the axial slices and maximum intensity projection (MIP), multiplanar reformation (MPR), volume rendering (VR) images to make the diagnosis,and the prototype of a commercial softwar (Syngo 2008G) was used to create a dual-energy direct bone removal CTA(DE-BR-CTA).Two neuroradiologists blinded to all clinical information independently reviewed the CTA images on a 3D workstation.Both of them evaluated the quality of the images,and made diagnosis. If an aneurysm was detected, the aneurysm maximal diameter and neck length were measured,and they observed the relationship between the aneurysm and its parent artery. Compared with DSA and/or operation, the characters of aneurysms were evaluated.Result1. Seventy-two patients were performed successfully on the dual-source CT in dual energy mode.A total of 39 intracranial aneurysms(32 patients) were discovered by the DE-CTA,and they were all confirmed by DSA or/and operation.40 intracranial aneurysms were discovered by DSA or operation. Because of the small aneurysm size,one of the aneurysms was not observed by DE-CTA. The accuracy of DE-CTA was 97.5%.28 patients have only one aneurysm,3 patients have two aneurysms.1 patient have five aneurysms. DE-CTA can clearly show its size,morphology,neck and relationship with parent artery.Location:3 aneurysms on ACA,6 aneurysms on MCA,10 aneurysm on ACoA,7 aneurysms on PCoA,6 aneurysms on the terminal portions of the bilateral internal carotid arteries(TICA),4 aneurysms on BA,2 aneurysms on VA,1 aneurysm on posterior inferior cerebellar artery(PICA).Size:the maximum diameter was 55.23mm,the minimum diameter was 2.12mm.Morphology:13 spindle aneurysms,26 round or ellipses aneurysms.The intra-aneurysm situation:3 aneurysms have thrombus the relationship with parent artery:11 aneurysms involved the important branch artery of the parent artery.2. Compared with DSA/or operation,the characters(the size of long axis,short axis and neck) were evaluated by paired-samples t test. There was no statistical difference between them.DE-CTA can show the size and neck of aneurysms, clearly, and it is a noninvasive, safe and credible method for diagnosis of intracranial aneurysm.ConclusionsThe methods of VR,MIP,MPR were excellent for visualizating aneurysms and relationships between the aneurysms and their parent vessels.All kinds of excellent DE-CTA reconstructed images have their own characters separately.DE-CTA is a sensitive,rapid and noninvasive method for detecting intracranial aneurysms.