平板旋转血管造影及三维重组在主动脉病变中的应用

目的:评价平板旋转血管造影及三维重组在主动脉病变临床应用的价值.方法:对比分析31例主动脉病变患者的CT或MR、二维血管造影、旋转血管造影及三维重组影像学资料,并对其结果对比分析.31例均为男性,年龄18～81岁,平均56.5岁.结果:行胸主动脉造影28例,发现主动脉夹层25例,动脉瘤1例,假性动脉瘤1例,主动脉弓畸形1例.行腹主动脉造影3例,发现动脉瘤2例,1例为腹主动脉动脉硬化性改变并主动脉钙化.所有主动脉夹层、真性及假性动脉瘤造影与CT或MRI对比,病变的形态、大小、位置均相符.其中有2例夹层的造影提示CT诊断破口位置错误.1例主动脉弓畸形,CT误诊为动脉瘤,而造影则可以清晰显示扩张纡曲的畸形主动脉弓.其中23例主动脉夹层和3例真性动脉瘤造影后进行支架主动脉腔内隔绝术的介入治疗,术后均行二维血管造影,支架位置准确,隔绝效果良好,没有出现并发症.结论:平板旋转血管造影及三维重组对主动脉病变的诊断和治疗有较高的临床应用价值,可以提高介入治疗的安全性和成功率.     

CT of thoracic aortic aneurysms

Aneurysms of the thoracic aorta are most often the result of arteriosclerotic disease. Other causes include degeneration of the medial layer of the aortic wall, either idiopathically or due to genetic disorders such as Marfan syndrome; aortic dissection; trauma; syphilis and other bacterial infection; noninfective aortitis; and congenital anomaly. We review normal anatomy of the aorta and discuss our technique and interpretation of computed tomography (CT) in the evaluation of the thoracic aorta. We illustrate the CT appearance of different types of aortic aneurysms as well as discuss the use of CT for assessing complications of aneurysms, for postoperative follow-up, and in the differentiation of aortic aneurysm from a paraaortic mass.     

Accuracy of plastic replica of aortic aneurysm using 3D-CT data for transluminal stent-grafting: experimental and clinical evaluation

PURPOSE: To plan stent-grafting for aortic aneurysms with complicated morphology, we prepared life-sized aortic replicas by laser stereolithography using helical 3D--CT data. The accuracy of the replica was evaluated by measurement of vessel phantoms and clinical 3D--CT data. METHOD: An imaginary aortic wall was created from helical CT images of the aorta, and a hollow plastic replica was produced by laser stereolithography. The accuracy of the replica was evaluated in five abdominal aortic aneurysms by experimental phantom studies and measurements of the replicas. RESULTS: The mean difference in measurements between 3D--CT images and model vessels and between 3D--CT images and aortic replicas was 0.2 mm each. Therefore, the difference in measurements between real aortic aneurysms and the replicas was at most 0.4 mm. CONCLUSION: The accuracy of the replica is satisfactory, making it useful for preoperative evaluation and simulation for stent-grafting.     

CT断层图像和三维重建在主动脉腔内隔绝术术前评估中的价值

目的比较CT断层图像和三维重建在主动脉腔内隔绝术术前评估中的价值。方法将接受主动脉腔内隔绝术的20例主动脉夹层瘤和12例腹主动脉瘤患者作为研究对象,术前分别在CT断层图像与三维重建图像上测量的各相关参数,与主动脉造影所测量的相同参数进行对照分析。结果CT断层图像上所测量的主动脉弓直径及各种长度指标均小于主动脉造影结果;夹层瘤近段主动脉直径及近端瘤颈直径、主动脉中段直径以及左右髂动脉直径均大于主动脉造影结果;三维重建所测量的上述各项参数与主动脉造影结果非常接近,并能清楚显示夹层分离的破裂口,而断层图像上不易发现破裂口;断层图像和三维重建在显示主动脉附壁血栓和测量最大瘤体直径方面优于主动脉造影。以三维重建测量为标准选择覆膜支架,所有患者均成功封闭瘤体。结论主动脉腔内隔绝术术前评估时应结合CT断层图像和三维重建图像综合分析,覆膜支架的选择应以三维重建测量结果为主。     

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。     

Spiral CT angiography of aortic dissection

Spiral CT angiography (CTA) is one of the newest imaging techniques used for the evaluation of aortic dissection. Current spiral CT scanners with high-performance tubes and subsecond scanning allow increased regions of coverage. Large volumes of data are rapidly acquired through the aorta during maximum contrast enhancement. Multiplanar reformat (MPR), curved planar reformat (CPR), and 3-D rendering techniques including shaded surface display (SSD) and maximum intensity projection (MIP) are then applied to the data to generate CT angiographic images of the aorta. Emergent spiral CTA may be performed in patients with suspected aortic dissection who are hemodynamically stable. Postprocessing is performed immediately following data acquisition and can provide additional information for aortic dissection diagnosis and clinical management. The technique, applications, and limitations of spiral CTA for the evaluation of aortic dissection will be discussed relative to the role of other imaging modalities.     

多层螺旋CT血管造影在主动脉瘤腔内带膜内支架置入术后并发症诊断中的应用

目的：探讨多层螺旋CT血管造影（CTA）在主动脉瘤腔内带膜内支架置入术后并发症诊断中的应用。方法：31例腹主动脉瘤和主动脉夹层腔内带膜内支架置入术后行多层螺旋CT血管造影，采用准直2.5mm，层厚3.0mm，螺矩6-8，重建方法为容积显示（VR）、表面遮盖显示（SSD）、最大密度投影法（MIP）及多层面重建法（MPR）。观察图像确定有无术后并发症，并比较4种重建方法对并发症的显示情况。结果：31例中有1例术后内支架出现局限性断裂，VR、MIP及MPR均清晰显示了内支架的变化，SSD未能显示。1例内支架展开不良，4种重建方法均明确显示；5例术后出现渗漏，VR及MPR清晰显示渗漏的部位、形态及内漏量，MIP、SSD仅显示其中的4例。在显示支架内血流情况及瘤周血栓方面，VR及MPR能明确支架内有无血栓形成及腔内带膜内支架置入术后的转归变化，VR及MPR显示1例术后支架内血栓形成，SSD及MIP未能显示。结论：多层螺旋CTA有利于主动脉瘤腔内带膜内支架置考试术后并发症的诊断；VR及MPR图像优于SSD及MIP，能为术后内支架情况作出更准确的判断 。     

Thoracic involvement of type A aortic dissection and intramural hematoma: diagnostic accuracy--comparison of emergency helical CT and surgical findings

PURPOSE: To assess the accuracy of various findings at emergency helical computed tomography (CT) for the evaluation of thoracic involvement of type A aortic dissection (AD) and type A intramural hematoma (IMH) and to compare these findings with those at surgical confirmation. MATERIALS AND METHODS: Fifty-seven patients with acute chest pain underwent emergency helical CT and subsequent surgery for type A AD or IMH. Patients in whom AD or IMH was detected in three segments of the thoracic aorta or those in whom there was a site of any entry tear, arch branch vessel involvement, pericardial effusion, or aortic arch anomaly were examined at helical CT. Sensitivity, specificity, and accuracy of helical CT, along with 95% CIs, were calculated by using surgical confirmation as the reference standard. RESULTS: For the detection of AD or IMH of the thoracic aorta, the accuracy of helical CT was 100%. The sensitivity, specificity, and accuracy, respectively, were 82%, 100%, and 84% for an entry tear; 95%, 100%, and 98% for arch branch vessel involvement; and 83%, 100%, and 91% for pericardial effusion. These values were all 100% for aortic arch anomalies. CONCLUSION: Emergency helical CT of the thorax depicts findings that are highly accurate in the evaluation of acute type A AD and IMH.     

CT in vascular pathologies

Since the introduction of helical scanners, CT angiography (CTA) has achieved an essential role in many vascular applications that were previously managed with conventional angiography. The performance of CTA is based on the accurate selection of collimation width, pitch, reconstruction spacing and scan delay, which must be modulated on the basis of the clinical issue. However, the major improvement of CT has been provided by the recent implementation of many post-processing techniques, such as multiplanar reformatting, shaded surface display, maximum intensity projections, 3D perspectives of surface and volume rendering, which simulate virtual intravascular endoscopy. The integration of the potentialities of the scanner and of the image processing techniques permitted improvement of: (a) the evaluation of aneurysms, dissection and vascular anomalies involving the thoracic aorta; (b) carotid artery stenosis; (c) aneurysms of abdominal aorta; (d) renal artery stenosis; (e) follow-up of renal artery stenting; and (f) acute or chronic pulmonary embolism. Our experience has shown that the assessment of arterial pathologies with CTA requires the integration of 3D post-processing techniques in most applications. Received 23 December 1997; Accepted 2 January 1998     

主动脉瘤多层螺旋CT血管成像的临床应用价值

目的探讨多层螺旋CT血管成像(MSCTA)技术在诊断主动脉瘤中的临床应用价值.资料与方法对32例主动脉瘤和主动脉夹层患者进行MSCTA检查,将原始图像传至工作站进行后处理,运用不同的重建方法对血管进行显示,包括多平面重组(MPR)、最大密度投影(MIP)、表面遮盖法(SSD)和容积再现(VR)技术.结果主动脉瘤13例,主动脉夹层19例,多种重建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技术对主动脉瘤的诊断具有独特的优越性,对于选择治疗方法、观察术后疗效及随访具有重要价值.     

获得性胸主动脉病变的MRI诊断

目的：评价ＭＲＩ对获得性胸主动脉病变的诊断价值。材料和方法：共３０例,２１例在ＧＥＶｅｃｔｒａ０．５Ｔ上行ＳＥ和ＣｉｎｅＭＲＩ检查,９例在ＧＥＳｉｇｎａ１．５Ｔ上行ＳＥ、ＣｉｎｅＭＲＩ、ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ检查。成像采用横断面、主动脉长轴和左室长轴观,部分加扫矢状面和冠状面。结果：共发现升主动脉瘤１０例、主动脉夹层１０例、主动脉扩张９例和降主动脉溃疡１例。经对照表明ＣｉｎｅＭＲＩ对合并的瓣膜病变、夹层真假腔、血栓和瘤内异常血流方式的显示较ＳＥ为佳,而ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ对整个胸主动脉形态及头臂血管的显示最佳。结论：多种ＭＲＩ技术综合运用诊断获得性胸主动脉病变可基本达到心血管造影效果。     

Postoperative evaluation of composite aortic grafts: comparison of angiography and CT

Postoperative angiography and computerised tomography were performed in 10 patients 8 to 57 months after surgical repair (nine composite, one distal graft) of aneurysms of the thoracic aorta (six dissecting, four true aneurysms). Angiography and angio-CT showed chronic dissection of the distal aorta in five of six patients with dissecting aneurysms and detected a pseudoaneurysm originating from the distal suture line in another patient. CT may serve as an initial procedure for postoperative examinations after surgery of aortic aneurysms to demonstrate the state of the false lumen and the formation of pseudoaneurysms. The coronary arteries and aortic valve function have to be evaluated by angiography.     

Dual-slice helical CT of the thoracic aorta

With the advent of helical CT, the capability of noninvasive imaging of the thoracic aorta has been enhanced considerably. In this article, we describe the potential of helical CT using dual-slice technology to evaluate thoracic aortic diseases such dissection, aneurysm, trauma, infection, inflammation, thromboembolic disease, and postoperative complications. Technical considerations for optimal CT imaging as well as limitations of helical CT are highlighted.     

Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation.     

Acute aortic abnormalities

Aneurysm and type B dissections account for most acute abdominal aortic abnormalities. The postsurgical aorta deserves special attention owing to the risk of complications. Most aortic abnormalities presenting acutely are emergencies that carry a high risk of mortality, and imaging plays a critical role in patient evaluation. Modern helical CT scanners provide excellent spatial resolution, are readily available, and allow for rapid imaging. For these reasons, helical CT angiography is the imaging modality of choice for initial evaluation of the acute aorta.     

Imaging of aortic dissection by helical computed tomography (CT)

Aortic dissection is the most frequent cause of aortic emergency, and its outcome is still frequently fatal. The management of this pathology has changed with the development of endovascular means. Nowadays, imaging modalities are helpful in management decision-making by providing information such as identification of entry tears along the aorta and involvement of the visceral branches of the abdominal aorta. Multi-slice CT scanning now appears to be the modality of choice for complete examination of the entire aorta. We review the parameters of image acquisition and contrast injection; appearances on CT of acute and chronic dissection are illustrated. Diagnostic pitfalls in CT imaging of acute dissection are discussed. Imaging of the post-surgical aorta and of chronic dissection is outlined. Intra-mural hematoma and penetrating aortic ulcer are subtypes of aortic dissection, and their appearances on CT scanning are also presented.     

主动脉壁内血肿的多层面螺旋CT诊断

目的:评价多层面螺旋CT诊断主动脉壁内血肿的价值.材料和方法:对23例怀疑主动脉病变的患者进行多层面螺旋CT扫描并诊断为主动脉壁内血肿.两名有经验的心血管放射医师按照CT标准做出诊断.使用16排多层面螺旋CT获得1.25mm层厚(1mm重建间隔)图像,应用多平面重建、曲面重建、最大密度投影和容积重建等方法显示壁内血肿及穿透溃疡.结果:23例主动脉壁内血肿中,1例A型,22例B型;B型壁内血肿中,仅累及降主动脉的8例,胸腹主动脉受累11例,局限于腹主动脉3例;11壁内血肿伴主动脉穿透溃疡,其中2例行带膜内支架治疗.结论:多层面螺旋CT能为主动脉壁内血肿的诊断、鉴别诊断和治疗提供重要信息.     

Abdominal aortic aneurysm. Detection of multilevel vascular pathology by time-resolved multiphase 3D gadolinium MR angiography: initial report.

OBJECTIVE: To evaluate multiphasic 3D gadolinium-enhanced magnetic resonance angiography (3D-Gd-MRA) for detection of vascular pathology at multiple levels of the aorta and iliac arteries. METHODS: In 18 patients with abdominal aortic aneurysm (n = 13), dissection (n = 3), or both (n = 2), multiphase 3D-Gd-MRA was performed acquiring five consecutive (6.8 seconds) 3D data sets in a single breath-hold. In each of the five time-resolved phases, vessel visibility of the abdominal aortic branches and iliac arteries was assessed. The extent of vessel involvement by the aneurysm or dissection seen on multiphase 3D-Gd-MRA was compared with standard imaging and surgical findings. Digital subtraction angiography was available for comparison in 4 cases, CT angiography in 10 cases. RESULTS: Due to the delayed filling of the aortic aneurysm, the proximal aortic branches and the aneurysm neck demonstrated an inversely related enhancement compared with the distal abdominal and iliac vessels (P < 0.001). Review of all five phases of multiphase 3D-Gd-MRA allowed optimal visualization of each vessel segment without any artifacts due to parenchymal or venous overlay. In dissections, review of three phases was required (P < 0.001) for diagnostic evaluation of the true and false lumens. Substantially more vessel involvement was detected on multiphase 3D-Gd-MRA; this was surgically confirmed in 10 of 11 cases and affected therapy management in 11 of 18 cases. CONCLUSIONS: Multiphase 3D-Gd-MRA is a convenient, robust, and safe technique for presurgical anatomic mapping of complex aortic aneurysms and dissections.     

多层螺旋CT血管成像技术诊断主动脉夹层的临床价值

目的:评价多层螺旋CT血管成像对主动脉夹层的临床诊断价值。方法:对29例主动脉夹层患者行多层螺旋CT平扫和增强扫描,将获得的容积数据进行表面覆盖法(SSD)、实时3D(RT-3D)、多平面重组(MPR)及曲面重组(CPR)等多种方式重组。16例经手术证实,8例经造影证实,其中2例术后进行了复查。结果:SSD能直观地显示主动脉夹层的全貌,病变与分支血管的关系,但显示管腔内的情况欠佳;RT-3D图像优于其它方法的重组图像,可清楚显示主动脉壁的钙化、测量各径线参数以及多角度动态观察病变,但重组时间较长。MPR能保留有助于定性诊断的密度CT征象,多方位地显示附壁血栓、真假腔,并能显示主动脉旁血肿等合并症,但缺乏病变与周围解剖结构的立体观。CPR可连续地显示主动脉夹层的范围,弥补MPR的不足。结论:多层螺旋CT血管造影可直观地显示主动脉夹层的特异性征象,综合应用多层螺旋CT的各种重组技术,为临床提供了一种安全可靠的诊断手段。