Clinical value of three-dimensional digital subtraction angiography in the endovascular treatment of intracranial aneurysms

Tianxiao Li; Dengwei Zong

摘要：BACKGROUND: The endovascular treatment of intracranial aneurysms requires clearly displayed anatomic structures of the aneurysm and the reference image of the aneurysm neck, the images of the form and struc ture of the aneurysm and the three-dimensional (3D) intracranial vascular structure are very important for the diagnosis and treatment of cerebral aneurysms. OBJECTIVE: To investigate the value of 3D digital subtraction angiography (3D DSA) in diagnosing intracra nial aneurysm, and compare the reliability with two-dimensional (2D) DSA in evaluating the intracranial aneurysm suitable for the endovascular occlusion: DESIGN: A double-blind case observation. SETTING: Department of Interventional Radiology, Henan People's Hospital. PARTICIPANTS: The patients, who were suspected to have intracranial aneurysms, were examined with 2D DSA and 3D DSA in Henan People's Hospital from October 2004 to October 2005. Fifty intracranial aneurysms were detected in 44 patients (19 males and 25 females) of 30-75 years, with an average of 51 years, including 5 cases were multiple aneurysms, including 2 aneurysms in 4 cases and 3 aneurysms in 1 case. The aneurysms located respectively at internal carotid artery (n =19), anterior cerebral artery (n =16), middle cerebral artery (n =8), basilar artery (n =6), and posterior inferior cerebellar artery (n =1 ). METHODS: The 50 ruptured intracranial aneurysms were examined with 2D DSA and 3D DSA. The method of volume reconstruction was applied to reconstruct the 3D DSA images, and the automatically generated images could be shifted, rotated and magnified, besides, the corresponding processing could also be performed, including resecting the unnecessary structure and sharpening margin of the images. Observations: ① Display of aneurysm neck: The site and range of the aneurysm neck, and the involvement of branches originated from the aneurysm arteries; ② Display of aneurysm form: The displays of aneurysm form and with or without arteries originated from the aneurysm; ③ Feasibility of endovascular occlusion: Whether the feasibility of endovascular occlusion could be judged based on the vascular anatomic form. The evaluative standards for the former two were cannot display, reluctantly display and clearly display, and those for the latter one were uncertain, possible but uncertain; certainly could not or certainly could be treated with endovascular occlusion. MAIN OUTCOME MEASURES: The images of 2D DSA and 3D DSA were observed and compared; The differences in the display of aneurysm neck, display of aneurysm form and feasibility of endovascular occlusion were compared between 2D DSA and 3D DSA. RESULTS: All the 44 patients with intracranial aneurysm (50 aneurysms) were involved in the analysis. ① Aneurysm necks displayed by 2D DSA and 3D DSA: Among the 50 ruptured aneurysms, the necks of 14 aneurysms could be clearly displayed by 2D DSA; 3D DSA could display the necks of all the aneurysm. ② Comparison of the the forms of aneurysm displayed by 2D DSA and 3D DSA: 2D DSA could clearly display the forms of 26 (36%) aneurysms; Whereas the 3D DSA with volume reconstruction clearly displayed the forms of all the aneurysms. ③ Feasibility of endovascular occlusion evaluated by 2D DSA and 3D DSA: 2D DSA believed that 6 cases were certainly unable to be treated with endovascular occlusion. 3D DSA showed that all the aneurysms were certainly able to be treated with endovascular occlusion, which was successfully performed. The reference images were obtained from the 3D DSA images in all the 49 aneurysms at the occlusion. The first spring ring was correctly selected for 48 aneurysms. CONCLUSION: 3D DSA can clearly display the form of the aneurysm, and the relationship between the aneurysm neck and the neighboring vessels, and it is helpful for obtaining the reference images in the endovascular occlusion of intracranial aneurysm; The diameter and length of the first spring ring can be correctly selected by the accurate measurement of aneurysm. 3D DSA has important instructive value in the occlusion of cerebral aneurysms.