特殊类型主动脉夹层的电子束CT表现及诊断

目的探讨表现特殊的主动脉夹层的电子束CT(EBCT)影像特征及诊断.材料和方法20例表现特殊的主动脉夹层,其中不典型夹层13例,三腔以上夹层动脉瘤3例,合并升主动脉壁内血肿的Stanford B型夹层2例,动脉瘤样夹层1例,外伤性主动脉夹层1例.结果主动脉不典型夹层为主动脉壁新月形或环形的低密度血肿包绕,常可见穿透性溃疡或钙化内移等征象;三腔以上夹层动脉瘤有2～3个内膜片,3～4个腔,瘤体管径较大;合并升主动脉壁内血肿的B型夹层见升主动脉管壁低密度新月形或环形增厚,降主动脉则见内膜片及真假两腔形成;动脉瘤样主动脉夹层见降主动脉局限性瘤样扩张,破口大,内膜片不易发现.1例外伤性夹层于主动脉弓峡部及降部起始见破裂内膜片.结论特殊类型的主动脉夹层表现各具特征,EBCT可清晰显示,是极适用于胸部急症的快速、无创的检查方法.     

Atherosclerotic penetrating ulcer of the aorta: typical morphology on CT. A review of five cases

Multiple penetrating atherosclerotic ulcers of the abdominal and thoracic aorta were detected in five elderly patients with well-known cardiovascular risk factors who were referred to our department for the investigation of an unrelated disease or acute chest pain. Penetrating ulcers of the aorta are defined as atherosclerotic intimal aortic plaques that ulcerate and penetrate into the media, allowing haematoma formation within the media. The progression of the disease is often limited by the presence of an associated fibrosis within the aortic media (medial fibrosis), but secondary formation of a pseudoaneurysm or very rarely a spontaneous perforation into the pleural space, mediastinum or peritoneal cavity have been observed. In our restrospective study we describe the morphology of the penetrating aortic ulcer on CT and in one case on sonography and angiography. A review of the literature is included.     

Orthogonal measurement of thoracic aorta luminal diameter using ECG-gated high-resolution contrast-enhanced MR angiography

PURPOSE: To compare orthogonal measurements of the thoracic aortic luminal diameter to standard axial measurements within the same patient population using ECG-gated high-resolution contrast-enhanced MR angiography (CE-MRA). MATERIALS AND METHODS: In all, 45 consecutive patients who had undergone CE-MRA for suspected disease of the thoracic aorta were evaluated retrospectively. Two diameter measurement techniques were performed for each patient's thoracic aorta: standard axial and orthogonal to the aorta. Seven anatomic locations along the thoracic aorta were used for measurement. The data obtained were compared using a paired, two-tailed t-test. RESULTS: We found that the aorta diameter measurements acquired from axial MRA images were significantly greater (P < 0.05) than those acquired from images orthogonal to the course of the aorta at six of seven anatomic sites. Overall, standard axial measurements were found to overestimate luminal diameter of the thoracic aorta by 0.24 cm (95% confidence interval [CI]: 0.14, 0.33) compared to orthogonal measurements. 13.3% of the patients were placed into a greater aorta size classification based on the axial versus the orthogonal measurements. CONCLUSION: Standard axial measurements can overestimate vessel size of the thoracic aorta. ECG-gated high-resolution CE-MRA can be used to measure orthogonal diameters of the thoracic aorta.     

85例Stanford B型主动脉夹层腔内修复治疗体会

目的 探讨胸主动脉腔内修复术(TEVAR)治疗Stanford B型主动脉夹层(AD)方法与疗效.方法 回顾性分析2010年1月至2016年4月采用TEVAR治疗的85例Stanford B型AD患者临床资料.85例患者均常规行左肱动脉穿刺,右侧股动脉直切口,升主动脉DSA造影明确AD破口位置、真假腔及与重要器官血管开口位置关系;置入覆膜血管内支架,封堵原发破口,升主动脉造影复查观察近端破口封闭情况及主动脉弓部分支血管、真假腔血流变化情况.结果 84例患者TEVAR手术成功,成功率100％;1例术前麻醉过程中突发AD破裂死亡.9例部分覆盖左锁骨下动脉,1例左锁骨下动脉“烟囱”支架完全封闭左颈总动脉和左锁骨下动脉,2例行无名动脉至左颈总动脉和左锁骨下动脉转流.Ⅰ型内漏2例,无住院期间死亡.术后随访3个月至3年,患者均存活,远端再发新破口2例.结论 TEVAR术治疗Stanford B型AD安全有效,严格把握手术指征、术中精细操作及加强术后院外管理是手术成功、提高远期生存率关键.     

Utility of computed tomography in the diagnosis of thoracic aneurysm in childhood

For an unusual case of saccular aneurysm of the thoracic aorta in a child, the computed tomographic demonstration of a totally vascular mass led directly to the definitive diagnosis by angiocardiography and eliminated the need for many additional imaging or chemical tests. This case illustrates how computed tomography can be beneficial in the potentially difficult diagnostic evaluation of pediatric medistinal masses.     

Long-Term Follow-Up After Endovascular Treatment of Acute Aortic Emergencies

Purpose To investigate the long-term outcome and efficacy of emergency treatment of acute aortic diseases with endovascular stent-grafts. Methods From September 1995 to April 2007, 37 patients (21 men, 16 women; age 53.9 ± 19.2 years, range 18–85 years) with acute complications of diseases of the descending thoracic aorta were treated by endovascular stent-grafts: traumatic aortic ruptures (n = 9), aortobronchial fistulas due to penetrating ulcer or hematothorax (n = 6), acute type B dissections with aortic wall hematoma, penetration, or ischemia (n = 13), and symptomatic aneurysm of the thoracic aorta (n = 9) with pain, penetration, or rupture. Diagnosis was confirmed by contrast-enhanced CT. Multiplanar reformations were used for measurement of the landing zones of the stent-grafts. Stent-grafts were inserted via femoral or iliac cut-down. Two procedures required aortofemoral bypass grafting prior to stent-grafting due to extensive arteriosclerotic stenosis of the iliac arteries. In this case the bypass graft was used for introduction of the stent-graft. Results A total of 46 stent-grafts were implanted: Vanguard/Stentor (n = 4), Talent (n = 31), and Valiant (n = 11). Stent-graft extension was necessary in 7 cases. In 3 cases primary graft extension was done during the initial procedure (in 1 case due to distal migration of the graft during stent release, in 2 cases due to the total length of the aortic aneurysm). In 4 cases secondary graft extensions were performed—for new aortic ulcers at the proximal stent struts (after 5 days) and distal to the graft (after 8 months) and recurrent aortobronchial fistulas 5 months and 9 years after the initial procedure—resulting in a total of 41 endovascular procedures. The 30-day mortality rate was 8% (3 of 37) and the overall follow-up was 29.9 ± 36.6 months (range 0–139 months). All patients with traumatic ruptures demonstrated an immediate sealing of bleeding. Patients with aortobronchial fistulas also demonstrated a satisfactory follow-up despite the necessity for reintervention and graft extension in 3 of 6 cases (50%). Two patients with type B dissection died due to mesenteric ischemia despite sufficient mesenteric blood flow being restored (but too late). Two suffered from neurologic complications, 1 from paraplegia and 1 from cerebral ischemia (probably embolic), 1 from penetrating ulcer, and 1 from persistent ischemia of the kidney. Five of 9 (56%) patients with symptomatic thoracic aneurysm demonstrated endoleaks during follow-up and there was an increase in the aneurysm in 1. Conclusion Endovascular treatment is safe and effective for emergency treatment of life-threatening acute thoracic aortic syndromes. Results are encouraging, particularly for traumatic aortic ruptures. However, regular follow-up is mandatory, particularly in the other pathologies, to identify late complications of the stent-graft and to perform appropriate additional corrections as required.     

Comparison of retrospectively ECG-gated and nongated MDCT of the chest in an emergency setting regarding workflow, image quality, and diagnostic certainty

Purpose This study aims to assess the influence of ECG-gated acquisition on workflow and to compare image quality and diagnostic certainty for retrospectively ECG-gated and nongated multidetector computed tomography of the chest in the emergency suite. Materials and methods Thirty-two consecutive patients were referred for both an ECG-gated and a nongated CT to rule out traumatic thoracic injury (n=15) or acute aortic dissection (n=17). The time from the start of the transportation from the emergency suite to the CT room until the start of the CT scan was recorded. Using a scoring system, the image quality of axial images and multiplanar reformats, the presence of disease, and the subjective diagnostic certainty were assessed with regard to the vascular structures, the bone structures, and the lung parenchyma. Results The time needed for transportation and patient preparation was 12.1±1.7 min (8.1–14.5 min). The motion artifacts of the thoracic aorta and the supra-aortic vessels were significantly reduced in the ECG-gated data acquisition compared with the nongated technique (P<0.001). Subjective diagnostic certainty for assessment of the aorta was significantly better using ECG gating. The image quality of the lung parenchyma (P<0.005), the spine (P<0.005), and the ribs (P<0.002) was inferior in the ECG-gated data sets but did not compromise the detection rate of traumatic lesions and fractures. Conclusion Performing ECG gating in the emergency room did not slow down the diagnostic workup. ECG-gated acquisition performed better in the assessment of the aorta, but image quality for lung and bone structures was slightly reduced. Further studies are required to assess the influence of the imaging technique on the diagnostic outcome.     

Regional variance of visually lossless threshold in compressed chest CT images: lung versus mediastinum and chest wall

Purpose

The purpose of this study was to characterize the heartbeat-related displacement of the thoracic aorta in patients with chronic aortic dissection type B (CADB).

Materials and methods

Electrocardiogram-gated computed tomography angiography was performed during inspiratory breath-hold in 11 patients with CADB: Collimation 16 mm × 1 mm, pitch 0.2, slice thickness 1 mm, reconstruction increment 0.8 mm. Multiplanar reformations were taken for 20 equidistant time instances through both ascending (AAo) and descending aorta (true lumen, DAoT; false lumen, DAoF) and the vertex of the aortic arch (VA). In-plane vessel displacement was determined by region of interest analysis.

Results

Mean displacement was 5.2 ± 1.7 mm (AAo), 1.6 ± 1.0 mm (VA), 0.9 ± 0.4 mm (DAoT), and 1.1 ± 0.4 mm (DAoF). This indicated a significant reduction of displacement from AAo to VA and DAoT (p < 0.05). The direction of displacement was anterior for AAo and cranial for VA.

Conclusion

In CADB, the thoracic aorta undergoes a heartbeat-related displacement that exhibits an unbalanced distribution of magnitude and direction along the thoracic vessel course. Since consecutive traction forces on the aortic wall have to be assumed, these observations may have implications on pathogenesis of and treatment strategies for CADB.     

Prognostic factors and indications for surgical treatment of acute aortic dissections: A report based on 191 observations

A total of 191 acute aortic dissections were examined to define prognostic factors for surgical intervention. Overall survival rate reached 40% in the 94 patients operated upon and 8% in the 97 patients not operated upon. Among the 122 patients with involved ascending aorta, survival rate was 2% in the 42 nonoperated patients versus 42% in 80 patients undergoing surgery. Since 1977, overall survival rate has reached 60% in the surgical group (21 of 35 patients and 20% in the nonsurgical group (5 of 25 patients). Factors that showed a significant correlation with postoperative death include: (1) persistent shock; (2) persistent anuria; (3) persistent neurologic deficit; (4) diffuse intravascular coagulation; and (5) involvement of either the celiac trunk, superior mesenteric artery. or both renal arteries at angiography. With the exception of those patients exhibiting any of these high-risk factors, emergency surgical treatment is recommended for all dissections that involve the ascending aorta.     

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。     

Artifact in SE phase images can mimic aortic dissection

Phase images of cardiac-triggered thoracic spin-echo scans can present an artifactual border-like feature across the aorta. This may be misinterpreted as a dissection. The artifact results from helical flow in the aorta; cause and appearance of the artifact are discussed.     

Treatment of a Persistent False Lumen with Aneurysm Formation Following Surgical Repair of Type A Dissection

We describe the case of a 68-year-old man who developed aneurysmal dilatation of the proximal descending thoracic aorta 8 years after repair of a type A dissection. The aneurysm was due to an anastomotic leak at the distal end of the previous repair in the ascending aorta with antegrade perfusion of the false lumen. Surgical repair of the anastomotic leak partially obliterated the false lumen and computed tomography scan demonstrated thrombosis in a large proportion of the false lumen aneurysm. Follow-up with surveillance scans showed persistent filling of this aneurysm due to retrograde flow of blood within the false lumen. Coil embolization of the false lumen within the thoracic aorta was performed which successfully thrombosed the aneurysm with a reduction in diameter. Late aneurysm formation may complicate type A dissection repairs during follow-up due to a persistent false lumen, especially if there is an anastomotic leak. This case report describes a strategy to deal with this difficult clinical problem.     

Computer tomography versus aortography in diagnosis of aortic dissection

The use of computed tomography (CT) versus aortography is evaluated in a limited study of 17 cases of aortic dissection (AD). With the constraints of the present state of the technology and lack of availability of CT scanners at some centers, aortography remains the premier and often the only diagnostic test to choose in an emergency. CT, however, may be an asset in the diagnosis of AD when: (1) atypical or misleading clinical presentations are evident that do not require aortography; (2) aortography is contraindicated in a weakened patient, when there is no emergency; (3) aortography is a risk while there is a strong suggestion of AD; (4) patency of a false channel must be confirmed. These circumstances were encountered in five patients. In addition, a localized infrarenal AD was fortuitously discovered in two patients presenting with abdominal visceral cancer. On patient follow-up, CT is less invasive and may be performed in asymptomatic patients undergoing treatment, thereby facilitating the early detection of complications. Detailed computed tomograms often yield superior diagnostic information only if the CT study includes rapid sequential scans immediately following a fast intravenous bolus of contrast material.     

Age‐related changes of regional pulse wave velocity in the descending aorta using Fourier velocity encoded M‐mode

Aortic pulse wave velocity (PWV) is an independent determinant of cardiovascular risk. Although aortic stiffening with age is well documented, the interaction between aging and regional aortic PWV is still a debated question. We measured global and regional PWV in the descending aorta of 56 healthy subjects aged 25–76 years using a one‐dimensional, interleaved, Fourier velocity encoded pulse sequence with cylindrical excitation. Repeatability across two magnetic resonance examinations (n = 19) and accuracy against intravascular pressure measurements (n = 4) were assessed. The global PWV was found to increase nonlinearly with age. The thoracic aorta was found to stiffen the most with age (PWV [thoracic, 20–40 years] = 4.7 ± 1.1 m/s; PWV [thoracic, 60–80 years] = 7.9 ± 1.5 m/s), followed by the mid‐ (PWV [mid‐abdominal, 20–40 years] = 4.9 ± 1.3 m/s; PWV [mid‐abdominal, 60–80 years] = 7.4 ± 1.9 m/s) and distal abdominal aorta (PWV [distal abdominal, 20–40 years] = 4.8 ± 1.4 m/s; PWV [distal abdominal, 60–80 years] = 5.7 ± 1.4 m/s). Good agreement was found between repeated magnetic resonance measurements and between magnetic resonance PWVs and the gold‐standard. Fourier velocity encoded M‐mode allowed to measure global and regional PWV in the descending aorta. There was a preferential stiffening of the thoracic aorta with age, which may be due to progressive fragmentation of elastin fibers in this region. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Endovascular Repair of Localized Pathological Lesions of the Descending Thoracic Aorta: Midterm Results

The endoluminal stent-graft represents an attractive and a less invasive technique for treatment of various diseases of the descending thoracic aorta. The purpose of this study was to evaluate the Talent endovascular stent-graft for the treatment of various localized diseases of the descending thoracic aorta. Over a 3-year period, Talent thoracic endografts were placed in 40 patients with a high surgical risk, presenting a localized lesion of the descending thoracic aorta: degenerative aneurysm (n = 13), acute traumatic rupture (n = 11), acute Stanford type B aortic dissection (n = 6), false aneurysm (n = 7), and penetrating atherosclerotic ulcer (n = 3). Fifteen patients (37.5%) were treated as emergencies. The feasibility of endovascular treatment and sizing of the aorta and stent-grafts were determined preoperatively by magnetic resonance angiography (MRA) and intraoperative angiography. Immediate and mid-term technical and clinical success was assessed by clinical and MRA follow-up. Endovascular treatment was completed successfully in all 40 patients, with no conversion to open repair or intraoperative mortality. The mean operative time was 37.5 ± 7 min. The overall 30-day mortality rate was 10% (n = 4), all in emergency cases, for causes not related to the endograft. The primary technical success was 92.5%. The mean follow-up period was 15 ± 5 months. The survival rate was 95% (n = 35). Diminution of the aneurismal size was observed in 47.5% (n = 19). We conclude that endovascular treatment of the various localized diseases of the descending thoracic aorta is a promising, feasible, alternative technique to open surgery in well-selected patients.     

Stanford B型主动脉夹层腔内修复术治疗体会

目的:探讨腔内修复术治疗Stanford B型主动脉夹层的效果。方法:对2005-09~2010-02期间18例Stanford B型主动脉夹层患者实行血管造影和血管腔内带膜支架植入手术治疗,术后3、6、12个月行CTA检查,观察手术疗效以及有无狭窄、移位和扭曲等术后并发症。结果:无中转开胸手术。除1例再发Stanford A型夹层破裂死亡外,其余患者均顺利出院。结论:主动脉夹层腔内修复术治疗Stanford B型主动脉夹层是一种安全有效的方法,早期结果满意,中远期效果还有待观察。     

急性主动脉综合征高风险MDCT特征评估及研究进展

急性主动脉综合征(AAS)包括主动脉夹层、壁内血肿、穿透性主动脉溃疡、创伤性主动脉撕裂及不稳定的胸主动脉瘤,是一组病情进展迅速,具有较高病死率的病变。采用多层螺旋CT可对AAS高风险影像特征进行动态定量评估。综述各类病变的病理机制及典型CT表现,从病灶位置、大小、累及范围、有无并发症及随访中的变化等角度介绍AAS高风险影像特征,分析其中哪些征象可为临床选择治疗方案提供依据。     

Thoracic aortic disease: Spectrum of multidetector computed tomography imaging findings

The clinical presentation of diseases involving the thoracic aorta ranges from a large number of asymptomatic patients with clinically undetectable thoracic aortic aneurysm to patients with symptoms of severe chest pain as a result of acute aortic dissection. Thoracic aortic disease often remains undiagnosed until a life-threatening complication occurs or the disease is discovered serendipitously on imaging studies performed for other purposes. Multidetector row computed tomography (MDCT) imaging of the aorta is used to diagnose various acute and chronic conditions, including aortic aneurysms, aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, traumatic injury, rupture, inflammatory disorders, and congenital malformations. This review illustrates the wide range of MDCT imaging findings of thoracic aortic disease.     

Correlation between thoracic aorta 18F-natrium fluoride uptake and cardiovascular risk

AIM: To investigating the relationship between thoracic and cardiac ¹⁸F-Natrium-Fluoride (18F-NaF) uptake, as a marker of ongoing calcification and cardiovascular risk factors.METHODS: Seventy-eight patients (44 females, mean age 63, range 44-83) underwent whole body 18F-NaF positron emission tomography/computed tomography. Cardiovascular risk (CVR) was used to divide these patients in three categories: Low (LR), medium (MR) and high risk (HR). 18F-NaF uptake was measured by manually drawing volumes of interest on the ascending aorta, on the aortic arch, on the descending aorta and on the myocardium; average standardized uptake value was normalized for blood-pool, to obtain target-to-background ratio (TBR). Values from the three aortic segments were then averaged to obtain an index of the whole thoracic aorta.RESULTS: A significant difference in whole thoracic aorta TBR was detected between HR and LR (1.84 ± 0.76 vs 1.07 ± 0.3, P < 0.001), but also between MR and HR-LR (1.4 ± 0.4, P < 0.02 and P < 0.01, respectively). Significance of this TBR stratification strongly varied among thoracic aorta subsegments and the lowest P values were reached in the descending aorta (P < 0.01). Myocardial uptake provided an effective CVR classes stratification (P < 0.001).Correlation between TBR and CVR was appreciable when the whole thoracic aorta was considered (R = 0.67), but it peaked when correlating the descending thoracic segment (R = 0.75), in comparison with the aortic arch and the ascending segment (R = 0.55 and 0.53, respectively).CONCLUSION: Fluoride uptake within the thoracic aorta wall effectively depicts patients’ risk class and correlates with cardiovascular risk. Descending aorta is the most effective in CVR determination.     

Obstruction of the Aorta and Left Pulmonary Artery After Gianturco Coil Occlusion of Patent Ductus Arteriosus

We report an unusual case of simultaneous obstruction of the left pulmonary artery and descending thoracic aorta after Gianturco coil occlusion in a 15-month-old boy. The diagnosis was made by echocardiography and cardiac angiography. At surgery, thrombi coating on the protruded parts of the Gianturco coil in the pulmonary artery and aorta were found.