3D DSA在颅内动脉瘤介入诊疗中的应用价值

目的评价3D DSA在颅内动脉瘤诊疗中的作用,并与2D DSA比较。方法50个破裂的颅内动脉瘤均行2D DSA及3DDSA检查。观察2D DSA及3D DSA(VR)对颅内动脉瘤瘤颈和瘤体形态的显示,评估血管内栓塞治疗的可行性。获取血管内栓塞治疗的参考图像。通过对瘤颈和瘤体的测量,正确选择第1枚弹簧圈的直径及长度。结果50个破裂的颅内动脉瘤中,2D DSA能清楚显示14个动脉瘤的瘤颈;VR能清楚显示所有动脉瘤的瘤颈。2D DSA能清楚显示26个动脉瘤的形态;VR能清楚显示所有动脉瘤的形态。2D DSA认为6例不能行血管内栓塞治疗;3D DSA显示全部能行血管内栓塞治疗并栓塞成功。49个颅内动脉瘤行血管内栓塞治疗时均从3D DSA获取参考图像。48个第1枚弹簧圈选择正确。结论3D DSA在评估颅内动脉瘤血管内栓塞治疗的可行性、获得参考图像、动脉瘤精确测量等方面具有重要的临床价值。     

Comparison of 2D and 3D digital subtraction angiography in evaluation of intracranial aneurysms

BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) is considered the criterion standard for depiction of intracranial aneurysms, it is often difficult to determine the relationship of overlapping vessels to aneurysms when using 2D DSA. We compared 2D and 3D DSA in evaluation of intracranial aneurysms. METHODS: Thirty-six consecutive patients with cerebral aneurysms underwent 2D and 3D DSA. After standard 2D DSA, rotational DSA was performed. Maximum intensity projection (MIP) and shaded surface display (SSD) images were created from the rotational DSA data sets. All images were assessed randomly for overall image quality, presence of aneurysm, presence of aneurysmal lobulation, visualization of aneurysmal neck, and relationship to adjacent vessels. Data analysis was conducted for 40 aneurysms treated by clip placement. RESULTS: One aneurysm that was not detected at 2D DSA was classified as uncertain on the basis of rotational DSA. All aneurysms were classified as probably or definitively present on the basis of MIP and SSD findings. Overall image quality of rotational DSA, MIP, and SSD was statistically inferior to that of the standard 2D DSA for visualization of distal arteries. However, MIP and SSD images were significantly superior to those of standard 2D DSA for all other evaluations. For detection of lobulation, SSD images were significantly superior to other images, and for visualization of aneurysmal neck and relationship to neighboring arteries, SSD images were significantly superior to those of rotational DSA. For evaluation of the relationship to neighboring arteries, MIP images were significantly superior to those of rotational DSA. CONCLUSION: Three-dimensional DSA, especially SSD, provided more detailed information for evaluating cerebral aneurysms than did standard 2D and rotational DSA.     

大动脉瘤螺旋CT血管造影与DSA比较研究

目的:探讨大动脉瘤螺旋CT 血管造影(SCTA) 检查技术和应用价值,为合理选择SCTA 和DSA 检查方法提供依据。材料和方法:34 例大动脉瘤,均行SCTA 和DSA 检查,其中29 例经手术证实,术后7 例随访检查用SCTA。SCTA用最大强度投影( MIP) 和表面遮盖显示(SSD) 两种方法重建血管。结果:胸主动瘤10 例,腹主动脉瘤15 例,胸腹主动脉连续性动脉瘤2 例,髂动脉瘤7 例。SCTA 和DSA 均能较好地显示大动脉瘤的部位、形状、范围及夹层情况。MIP 重建图像能显示动脉壁钙化,SSD 重建图像能较好地显示动脉瘤的三维形态,SCTA 结合CT 横断面及多平面重建图像可更清楚显示动脉腔、动脉壁、附壁血栓及动脉周围组织结构。DSA 图像空间分辨力较SCTA 高,但不能清楚显示动脉壁、附壁血栓及动脉周围组织结构。结论:对大动脉瘤可首选SCTA 检查以替代DSA 检查。     

主动脉瘤的CT诊断

目的:探讨螺旋CT血管造影在主动脉瘤中的诊断价值。方法:24例主动脉瘤患者行多层螺旋CT(MSCTA)血管造影并进行二维和三维图像重组,重组方法包括多平面重组(MPR),容积重组(VR),表面遮盖成像(SSD),最大密度投影(MIP)。结果:真性主动脉瘤6例,主动脉夹层动脉瘤17例,1例假性动脉瘤。多种重组图像与轴位图像相结合能清晰地显示动脉瘤的解剖细节及其与周围器官的空间解剖关系。结论:MSCTA对主动脉瘤有较高的临床诊断价值。     

64层3D-CTA与3D-DSA对颅内动脉瘤评价的对比研究

目的 对比评价64层螺旋CT三维血管造影(3D-CTA)与三维数字减影血管造影(3D-DSA)对颅内动脉瘤的诊断价值.方法 28例临床怀疑颅内动脉瘤的患者均行64层螺旋CT血管造影和DSA,CT三维后处理主要包括容积重建(VR)及最大密度投影(MIP).常规二维DSA检查后,对可疑病变血管行旋转DSA检查,应用三维工作软件行3D后处理,比较3D-CTA与3D-DSA对动脉瘤显示的价值.结果 28例病例中22例CTA和DSA均显示动脉瘤并经手术或栓塞证实,其中1例CTA和DSA显示单个动脉瘤,手术证实为2个动脉瘤,1例CTA显示假阳性.3D-CTA与3D-DSA均能清楚显示动脉瘤形状、瘤径指向、瘤体直径、瘤颈、载瘤动脉、瘤体穿动脉情况,两者无明显差异.结论 64层3D-CTA在颅内动脉瘤诊断及细节显示上与3D-DSA无明显差异,一定程度上应能替代血管造影,指导临床治疗.     

MR angiography at 3T versus digital subtraction angiography in the follow-up of intracranial aneurysms treated with detachable coils

BACKGROUND AND PURPOSE: Digital subtraction angiography (DSA) is used to follow-up intracranial aneurysms treated with detachable coils to identify recurrence and determine need for additional treatment. However, DSA is invasive and involves a small risk of neurologic complications. We assessed the feasibility and usefulness of 3D time-of-flight (TOF) MR angiography (MRA) performed at 3T compared with DSA for the follow-up of coil-treated intracranial aneurysms. METHODS: In a prospective study, 20 consecutive patients with 21 intracranial aneurysms treated with coils underwent DSA and nonenhanced and enhanced multiple overlapping thin-slab acquisition 3D TOF MRA at 3T on the same day at a mean follow-up of 6 months (range, 4-14 months) after coil placement. MRA images were evaluated for presence of artifacts, presence and size of aneurysm remnants and recurrences, patency of parent and branch vessels, and added value of contrast material enhancement. MRA and DSA findings were compared. RESULTS: Interobserver agreement of MRA was good, as was agreement between MRA and DSA. All three recurrences that needed additional treatment were detected with MRA. Minor disagreement occurred in four cases: three coil-treated aneurysms were scored on MRA images as having a small remnant, whereas on DSA images these aneurysms were occluded; the other aneurysm was scored on MRA images as having a small remnant, whereas on DSA images this was a small recurrence. Use of contrast material had no additional value. Coil-related MR imaging artifacts were minimal and did not interfere with evaluation of the occlusion status of the aneurysm. CONCLUSION: High-spatial-resolution 3D TOF MRA at 3T is feasible and useful in the follow-up of patients with intracranial aneurysms treated with coil placement.     

螺旋CT血管造影在脑动脉瘤血管内栓塞治疗中的价值

目的 探讨螺旋CT血管造影（SCTA）在指导脑动脉瘤血管内栓塞治疗中的应用价值。方法 脑动脉瘤患者48例,行SCTA明确动脉瘤的部位、形态及与载瘤动脉、邻近其他结构的关系,选择最佳显示动脉瘤与载瘤动脉关系的角度,测量动脉瘤的瘤颈、瘤体大小及动脉瘤与载瘤动脉的夹角,以指导血管内电解可脱弹簧圈（GDC）栓塞治疗。1周内行DSA造影,合适病例行GDC栓塞治疗,将SCTA与DSA结果进行对照比较。结果 （1）SCTA检出了DSA确诊的56个脑动脉瘤中的53个（94．6％）,正确诊断51个（91．1％）。（2）43个脑动脉瘤选择血管内GDC栓塞治疗,SCTA选择的血管内治疗的最佳投照角度与DSA相符41个（95．35）,SCTA测量这41个动脉瘤的瘤体与载瘤动脉夹角、瘤体及瘤颈大小并分别与DSA测量值比较,差异均无显著性意义（P值均＞0．05）。SCTA选择最佳投照角度及测量数值应以最大密度投影（MIP）图像为准,结合表面遮盖法（SSD）图像。结论 SCTA不仅对脑动脉瘤的诊断准确率高,而且对动脉瘤治疗方案的制定、术前准确及血管内栓塞治疗有很高的指导价值。     

16层螺旋CT血管造影诊断颅内动脉瘤

目的:探讨16层螺旋CT血管造影(MSCTA)诊断颅内动脉瘤的准确性。材料和方法:30例临床怀疑颅内动脉瘤的患者分别进行16层螺旋CT脑血管三维成像(3D-MSCTA)和数字减影血管造影(DSA),所有病例均完成多层面重建(MPR)、三维表面遮盖显示(SSD)、容积显示(VR)和薄层块最大密度投影(MIP),并对照手术或介入栓塞结果评估其诊断价值。结果:MSCTA共发现24例28个动脉瘤,其中22例为单个动脉瘤,2例为两个动脉瘤。动脉瘤直径最小2.7mm,最大35mm。MSCTA能清晰显示动脉瘤的瘤体大小、瘤颈、瘤轴指向、载瘤动脉及其动脉瘤与临近血管分支和骨性组织间的空间关系。23例与手术/DSA结果一致。结论:MSCTA诊断颅内动脉瘤有较高准确性,可部分取代DSA造影检查。     

Clinical usefulness of unsubtracted 3D digital angiography compared with rotational digital angiography in the pretreatment evaluation of intracranial aneurysms

BACKGROUND AND PURPOSE: Three-dimensional digital subtraction angiography (DSA) is useful as a supplement to 2D DSA in the pretreatment evaluation of intracranial aneurysms. However, the clinical efficacy of 3D digital angiography (DA) that is generated from unsubtracted rotational images has not been established. The purpose of this study was to assess whether 3D DA provides additional useful information to that of rotational DA in the preoperative evaluation of intracranial aneurysms. METHODS: This prospective study comprised 23 patients (age range, 37-83 years) with ruptured aneurysms who underwent angiography. Two radiologists independently evaluated the rotational DA images and the maximum intensity projection, shaded surface display, and volume-rendering 3D DA images, in combination with 2D DSA images. A four-point scoring system was used to evaluate aneurysm detection and delineation. Referring neurosurgeons were questioned as to whether the information obtained with 3D DA was useful for treatment decisions. RESULTS: Thirty aneurysms were confirmed by surgery or endovascular treatment. In detection and delineation of the 30 confirmed aneurysms, overall mean scores were highest with volume-rendering 3D DA and lowest with rotational DA. Compared with rotational DA, volume-rendering 3D DA demonstrated 27 additional findings in 14 (47%) of 30 aneurysms: detection of an aneurysm (n = 2), and delineation of aneurysm neck, shape, and relationship to adjacent arteries (n = 25). The information provided by 3D DA was useful for following treatment in five (22%) of 23 patients. CONCLUSION: In the preoperative evaluation of intracranial aneurysms, 3D DA can provide additional useful information to that of rotational DA.     

64层螺旋CT脑血管造影在颅内动脉瘤诊断中的应用

目的:与DSA相对照,探讨64层螺旋CT脑血管造影在颅内动脉瘤中的诊断价值。方法:对29例临床怀疑颅内动脉瘤的患者行64层螺旋CT脑血管造影(CTA)和DSA检查,使用GE64层Lightspeed VCT获得原始图像,所有病例均采用多层面重建(multiplanar reconstruction,MPR)、容积再现(volume rendering,VR)、薄层块最大密度投影(thin-slab maximumintensity projectjon,TS MIP)。后处理图像及DSA图像由2位放射科医生共同评估。结果:29例患者中,DSA证实25例共27个动脉瘤,其中2例为2个动脉瘤。与DSA结果相对照,CTA共检出25例26个动脉瘤,漏诊了1个颈出动脉瘤。CTA清晰显示了动脉瘤的形态、大小及载瘤动脉,3例动脉瘤瘤颈DSA未显示,CTA显示了全部动脉瘤的瘤颈。结论:64层CTA在颅内动脉瘤的诊断中具有极高价值,特别在显示动脉瘤瘤颈方面具有独特的优势,对临床治疗具有指导意义。     

螺旋CT血管造影三维成像在脑动脉瘤诊断中的应用

目的:探讨螺旋CT血管造影(SCTA)三维成像及其在脑动脉瘤诊断中的作用。方法:分析23例经手术或血管造影证实的脑动脉瘤,将其术前行螺旋CT血管造影容积扫描所得数据传输到工作站,用表面遮盖法(SSD)、最大密度投影(MIP)等技术进行3D重建。结果:23例患者,共检出脑动脉瘤25个,其中2例为2个。所示病例经SSD、MIP重建处理后能够全面直观地显示动脉瘤的大小、形态、位置,能多方位观察瘤体与载瘤动脉的空间解剖关系。结论:运用多种三维成像技术,能充分显示动脉瘤的空间解剖结构,可部分代替传统脑血管造影,并可作为该病的临床筛选手段。     

Three-dimensional reconstructed rotational digital subtraction angiography in planning treatment of intracranial aneurysms

We evaluated three-dimensional (3D) reconstructions of 200 ° rotational digital subtraction angiography (DSA) images for their contributions to improving the safety of endovascular embolization of intracranial aneurysms. Standard DSA and 200 ° rotational DSA were performed in 40 adult patients (aged 21–77 years) with 45 intracranial aneurysms. Information obtainable from standard DSA and 3D-DSA images about aneurysm shape and size was compared. In 40 (89 %) of the 45 aneurysms 3D-DSA gave additional information about the anatomy of the aneurysm. In 17 (43 %) of these cases aneurysm anatomy could be visualized better on 3D-DSA than on standard DSA images. In three cases only 3D-DSA images showed blood vessels originating from the aneurysm. Reconstructed 3D images were also helpful in visualizing partially clipped aneurysms. On maximum-intensity projection images it was even possible to depict previously embolized aneurysms. Blood vessels originating from the aneurysm are visible on 3D-DSA images, and even previously clipped aneurysms can be visualized well. Rotational DSA with 3D reconstruction is a helpful tool in the assessment of intracranial aneurysms. Received: 7 September 1999; Revised: 26 November 1999; Accepted: 26 November 1999     

Follow-up of intracranial aneurysms selectively treated with coils: Prospective evaluation of contrast-enhanced MR angiography

BACKGROUND AND PURPOSE: The aim of this study was to determine the feasibility and usefulness of contrast-enhanced MR angiography (CE-MRA) for the follow-up of intracranial aneurysms treated with detachable coils, by comparing CE-MRA with digital subtraction angiography (DSA) and 3D time-of- flight (TOF) MRA. METHODS: Thirty-two patients with 42 treated aneurysms were included in the study; 6 had been treated for multiple aneurysms. All MRAs were performed with a 1.5T unit within 48 hours of DSA. We performed 2 types of acquisition: a 3D TOF sequence and CE-MRA. Twenty-eight patients were included 1 year after endovascular treatment, and 4 patients, after 3 years or more. DSA was the technique of reference for the detection of a residual neck or residual aneurysm. RESULTS: Compared with DSA, the sensitivity of MRA was good. For the detection of residual neck, there was no significant difference between the results of 3D TOF MRA (sensitivity, 75%-87.5%; specificity, 92.9%, according to both readers) and CE-MRA (sensitivity, 75%-82.1%; specificity, 85.7%-92.9%). For the detection of residual aneurysm, sensitivity and specificity of both techniques were the same, respectively 80%-100% and 97.3%-100%. Therefore, CE-MRA was not better than 3D TOF MRA for the detection of residual neck or residual aneurysm. For large treated aneurysms, there was no difference between decisions regarding further therapy after CE and 3D TOF MRA, even though CE-MRA with a short echotime and enhancement gave fewer artifacts and better visualization of recanalization than 3D TOF MRA. The interpretation of transverse source images and the detection of coil mesh packing seemed easier with 3D TOF imaging. CONCLUSION: This prospective study did not show that CE-MRA was significantly better than 3D TOF MRA for depicting aneurysm or neck remnants after selective endovascular treatment using coils. For aneurysms treated with coils, 3D TOF MRA seems a valid and useful technique for the follow-up of coiled aneurysms.     

Spiral CT angiography and surgical correlations in the evaluation of intracranial aneurysms

We investigated the accuracy of spiral computed tomography angiography (CTA) in the detection and study of intracranial aneurysms by comparing CTA with selective angiograms and surgical findings. Twenty-six patients (9 men and 17 women; mean age 53.1 ± 1.8 years) with suspected intracranial aneurysms were submitted to CTA (1- to 2-mm slices, pitch 1:1, 24 s, RI = 1) after a conventional CT examination showing subarachnoid hemorrhage (SAH) in 19 cases and during neuroradiological investigations performed for other reasons in 7 cases. One hundred twenty to 150 ml iodate contrast agent (0.3–0.4 gI/ml) were injected intravenously at 5 ml/s rate and with 12- to 25-s delay calculated with a preliminary test bolus. Three-dimensional shaded surface display (3D SSD) and maximum intensity projection (MIP) reconstructions were obtained from axial images. Then, within 48 h, all patients were submitted to digital subtraction angiography (DSA), with separate assessment of CTA and DSA findings. Twenty-two aneurysms shown by CTA were confirmed at DSA and surgery (true positives), whereas the vascular lesion was not confirmed at DSA in 2 cases (false positives). The presence of intracranial aneurysms was excluded at both CTA and subsequent DSA in 7 cases (true negatives) and there were no false negatives; sensitivity was 100 %, specificity 77.8 %, and diagnostic accuracy 93.5 %. Computed tomography angiography aneurysm location was confirmed at surgery in all cases, with very high accuracy in assessing the presence of an aneurysm neck (100 %). Computed tomography angiography accurately depicted the aneurysm shape in 20 of 22 cases, but failed to depict its multilobed nature in 2 cases. The mean aneurysm diameter calculated at CTA was 0.99 ± 0.12 cm vs 1.09 ± 0.11 cm at surgery (p < 0.01). The present results suggest that the high sensitivity of CTA, if confirmed by further studies, might help in avoiding having to resort to arteriography after negative CTA in SAH patients. Received 15 July 1997; Revision received 30 September 1997; Accepted 5 November 1997     

Magnetic resonance angiography with contrast media bolus in the evaluation of aneurysms of the abdominal aorta

PURPOSE: To investigate the potentials of 3D breath-hold contrast-enhanced Magnetic Resonance Angiography (MRA) in the diagnosis, follow-up and treatment planning of abdominal aortic aneurysms. MATERIAL AND METHODS: Twenty-four patients with infrarenal aortic aneurysm underwent MRA. We used a 1.5 T unit (GE Horizon, Echospeed 8.2), a phased array surface coil and 3D Fast SPGR T1-weighted sequences acquired on the coronal plane during patient breath-hold and after contrast agent i.v. administration. A bolus-test was done before angiography to optimize imaging delay time. After 3D MRA a Fast-SPGR T1-weighted sequence was acquired on the axial plane. The 3D MRA source images were processed with the MIP algorithm. Qualitative and quantitative analyses were carried out. Helical CT was performed in 6 cases and DSA in 7 cases. Surgery was the reference standard in 15 patients. RESULTS: MRA depicted aneurysm thrombosis in 22 cases, carrefour involvement in 18 cases and iliac arteries involvement in 3 cases. Accessory renal arteries were shown in 4 cases; iliac artery stenosis was associated in 5 cases. There was agreement between MR and Helical CT and DSA findings: surgery confirmed MRA results in 15/15 cases. CONCLUSIONS: 3D contrast-enhanced MRA can be considered the method of choice in the follow-up and treatment planning of abdominal aortic aneurysms, because it provides both angiographic and tomographic images: this allows to obtain more information, noninvasively and without the use of ionizing radiations.     

螺旋CT血管造影不同重组方法对颅底动脉瘤的诊断研究

目的:研究螺旋CT血管造影(CTA)不同重组方法对颅底动脉瘤的诊断价值。方法:对43例原发性蛛网膜下腔出血(SAH)的动脉瘤疑似患者行CTA和DSA,由2位经验丰富医生阅片,作双盲对照研究。CTA后处理采用容积再现(VR)、最大密度投影(MIP)、表面遮盖法(SSD),辅以调整CT阈值和精细去颅底骨方法。结果:43例SAH中动脉瘤37例40个,均经DSA证实,其中17个手术切除,21个介入栓塞,2个未作处理。CTA发现动脉瘤36例38个。对动脉瘤体径>3mm者,CTA与DSA检出率相仿;VR能发现体径为1.72mm的微小动脉瘤。结论:CTA能精确显示其三维空间形态,对直径>3mm动脉瘤,CTA与DSA效能相仿,在VR、MIP、SSD三种技术中以VR品质最优,能发现颅底微小动脉瘤。     

多层螺旋CT 三维血管造影容积重建成像在颅内动脉瘤中的诊断价值

目的探讨多层面螺旋CT三维血管造影(MS 3D-CTA)容积重建(VR)技术在颅内动脉瘤中的诊断价值.方法对109例临床怀疑颅内动脉瘤的病人行MS 3D-CTA和DSA检查.使用GE Lightspeed pro 16层螺旋CT扫描仪获得原始图像,所有病例均采用VR技术对图像进行三维重建,20例同时有最大密度投影(MIP)辅助检查.VR和MIP后处理图像以及DSA图像由3位放射科医生用双盲法进行分析.结果DSA和手术证实83例共94个动脉瘤,其中单发74例,多发9例(7例2个动脉瘤,2例3个动脉瘤).VR图像上所测动脉瘤大小为1.3～32 mm,与DSA比较无显著性差异(t=1.548,P＞0.05).VR对颅内动脉瘤的敏感度为96.8%,特异度为92.9%,准确度为95.9%,阳性预测值为97.8%,阴性预测值为89.7%;DSA敏感度为97.9%,特异度为96.3%,准确度为97.5%,阳性预测值为98.9%,阴性预测值为92.9%.94个动脉瘤中,89个(94.7%)动脉瘤在VR图像上能清晰显示瘤体、瘤颈与载瘤动脉的三维空间关系,DSA为57个(60.6%).结论MS 3D-CTA VR的敏感度、特异度和准确度均较高,是一种快捷、经济和有效的检查技术.     

Preoperative evaluation of intracranial aneurysms: usefulness of intraarterial 3D CT angiography and conventional angiography with a combined unit--initial experience

PURPOSE: To assess the usefulness of intraarterial computed tomographic (CT) angiography in conjunction with digital subtraction angiography (DSA) by using a combined CT and angiographic unit in the preoperative evaluation of intracranial aneurysms. MATERIALS AND METHODS: Prospectively, 22 patients with or without subarachnoid hemorrhage underwent CT angiography in conjunction with DSA. Two radiologists independently evaluated DSA and CT angiographic images. Referring neurosurgeons were questioned as to how the additional information provided by CT angiography changed patient treatment. RESULTS: Intraarterial CT angiography was superior to DSA for use in aneurysm detection in three (12%) of 26 aneurysms and for delineation of aneurysm shape, neck, and location in more than half. In 14 (64%) of 22 patients, CT angiography demonstrated 18 additional findings: a very small aneurysm (n = 2), aneurysm shape and neck (n = 6), relationship of the aneurysm to adjacent arteries or bone structure (n = 8), and branches deriving from the aneurysm (n = 2). In four (27%) of 15 patients who underwent surgery or embolization, additional information obtained at CT angiography affected the treatment. CT angiography failed to clearly demonstrate an aneurysm adjacent to bone structures and small perforators, which were derived from the parent artery. CONCLUSION: Intraarterial CT angiography is useful for preoperative evaluation of intracranial aneurysms as a supplement to DSA.     

The role of MR angiography in the pretreatment assessment of intracranial aneurysms: a comparative study

BACKGROUND AND PURPOSE: With developments in coil technology, intracranial aneurysms are being treated increasingly by the endovascular route. Endovascular treatment of aneurysms requires an accurate depiction of the aneurysm neck and its relation to parent and branch vessels preoperatively. Our goal was to estimate the clinical efficacy of MR angiography (MRA) in the pretreatment assessment of ruptured and unruptured intracranial aneurysms. We compared MRA source data (axial acquired partitions), multiplanar reconstruction (MPR) of these data, as well as maximum intensity projection (MIP) and 3D-isosurface images with intraarterial digital subtraction angiography (IA-DSA). METHODS: The study was performed in 29 patients with 42 intracerebral aneurysms. The MRA data were examined in four different forms--as axial source data, MPR images of the source data, and MIP and 3D isosurface--rendered images. A composite standard of reference for each aneurysm was then constructed using this information together with the IA-DSA findings by looking at aneurysm detection rate, aneurysm morphology, neck interpretation, and branch vessel relationship to the aneurysm. All techniques, including conventional IA-DSA, were then scored independently on a five-point scale from 1 (non diagnostic) to 5 (excellent correlation with the standard of reference) for each of the aneurysm components as compared with the composite picture. An overall score for each technique was also obtained. RESULTS: Of the 42 aneurysms examined, 34 were small (<10 mm), six were large (10-25 mm), and two were giant (>25 mm). Three aneurysms were not detected with MRA. These were smaller than 3 mm and either in an anatomically difficult location (middle cerebral artery bifurcation) or obscured by adjacent hematoma. Two large aneurysms were depicted as undersized by IA-DSA owing to the presence of intramural thrombus shown by MRA axial source data. IA-DSA received the highest scores overall and in three of the four subgroups. Three-dimensional isosurface reconstructions scored higher than did IA-DSA for depiction of the aneurysm neck, although this difference was not significant. The MPR and 3D-isosurface images were comparable to those of IA-DSA in all categories. MPR images were particularly useful for defining branch vessels and the aneurysm neck. MIP images scored poorly in all subgroups (P < .005) compared with IA-DSA findings, except for in aneurysm detection. Source data images were significantly inferior to those of IA-DSA in all categories (P < .005). CONCLUSION: MRA is currently inferior to IA-DSA in pretreatment assessment of intracranial aneurysms, and can miss small lesions (<3 mm). It can, however, provide complementary information to IA-DSA, particularly in anatomically complex areas or in the presence of intramural thrombus. If MRA is used in aneurysm assessment, a meticulous technique with reference to both axial source data and MPR is mandatory. The axial source data should not be interpreted in isolation. Three-dimensional isosurface images are comparable to those of IA-DSA and are more reliable than are MIP images, which should be interpreted with caution.     

Three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) and contrast-enhanced MRA of intracranial aneurysms treated with platinum coils

Background: Contrast-enhanced magnetic resonance angiography (CE-MRA) is less prone to flow-related signal intensity loss than three-dimensional time-of-flight (3D TOF) MRA and may therefore be more sensitive for detection of residual patency in platinum coil-treated intracranial aneurysms.

Purpose: To compare MRA and CE-MRA in the follow-up of intracranial aneurysms treated with platinum coils.

Material and Methods: CE-MRA and 3D TOF MRA (pre- and postcontrast injection) of the intracranial vasculature was performed at 1.5T in 38 patients (47 aneurysms) referred for DSA in the follow-up of coiled intracranial aneurysms.

Results: DSA showed aneurysm patency in 22/47 investigations. Patent aneurysm components were observed with CE-MRA in 18/22 cases, and with 3D TOF MRA in 21/22 cases. There was no significant difference in patent aneurysm component size between CE-MRA and 3D TOF MRA. In addition, CE-MRA showed six, 3D TOF MRA before contrast injection showed seven, and 3D TOF MRA after contrast injection showed eight cases with patent aneurysm components not observed on DSA.

Conclusion: 3D TOF MRA was highly sensitive for detection of patent aneurysm components, and at least as sensitive as CE-MRA. Residual aneurysm patency seems to be better visualized with MRA than with DSA in some cases.