Improved diagnosis of vascular dissection by ultrasound B-flow: a comparison with color-coded Doppler and power Doppler sonography

The purpose was to evaluate the diagnostic results of different ultrasound techniques: color-coded Doppler (CCD), power Doppler (PD) and B-flow in the diagnosis of vascular dissection. Findings from 68 patients with arterial dissection proven either by vascular ultrasound (US) or by magnetic resonance angiography (MRA), computed tomographic angiography (CTA) or intra-arterial digital subtraction angiography (DSA) were reviewed in retrospect. The study compared results from three different modes of ultrasound, i.e., CCD, PD and B-flow, in dissections of the carotid artery (n=11), of the vertebral artery (n=9), of the abdominal aorta (n=13), of the iliac artery (n=12) and of the femoral artery (n=23). MRA, CTA and DSA were considered as reference standard. The sensitivity of CCD for detecting all dissections was 78%, 84% for the PD and 98% for B-flow. For carotid artery dissection, the sensitivity of CCD, PD and B-flow was 82, 91 and 98%, for the vertebral artery 67, 78 and 98%, for the abdominal aorta 85, 85 and 98%, for the iliac artery 67, 75 and 98%, for the femoral artery 83, 87 and 98%, respectively. Intima flaps, fissures of membranes and residual flow within the true and false lumen were better detected by B-flow than by CCD and PD. The lack of angle dependence of the US probe in B-flow made the examination procedure easier. In the cine mode of B-flow, the pulse synchronic movement of the membrane was more apparent than in any other imaging method. With B-flow, accuracy for the diagnosis of arterial dissection is improved compared to CCD and PD. Flow within the true and false lumen, low-echo thrombi, intramural hematoma and even movements of the dissection membrane are clearly distinguished.     

主动脉不典型夹层的多层螺旋CT诊断

目的:探讨多层螺旋CT(MSCT)对主动脉不典型夹层的诊断和临床应用价值.方法:采用东芝Aquilion 16层螺旋CT扫描机,对21例主诉急性胸背痛患者进行MSCT检查并诊断为主动脉不典型夹层.结果:21例按Stanford分型,A型5例,B型16例.MSCT所见主动脉壁内血肿的直接征象:主动脉壁呈新月形或环形增厚≥5mm,无内膜破裂形成的双腔主动脉征象.间接征象:钙化内移5例,穿透性溃疡征9例,主动脉壁粥样硬化改变13例,内膜渗漏5例.并发征象:心包积液3例,胸腔积液10例,主要分支血管受累3例,主动脉夹层6例,主动脉瘤2例.结论:MSCT是一种快速、无创的检查方法,能为主动脉不典型夹层的诊断和治疗提供重要信息.MSCT可作为主动脉不典型夹层的首选诊断及随访检查手段.     

彩超在诊断主动脉夹层中的应用

目的评价彩超诊断主动脉夹层的临床价值。方法采用HP—Image Point Hx和PH—HD11彩超，对2000年2月至2007年1月间诊断的21例主动脉夹层患者进行总结分析。结果19例主动脉夹层患者均经彩超确诊，2例可疑病例经尸检证实。结论彩超对主动脉夹层的诊断、治疗方案选择及预后判断具有重要的临床价值。     

Bloodless aortic dissection

“Bloodless aortic dissection” is a rare cause of sudden death due to an aortic dissection without intimal tears and with no blood present within the dissected aortic wall. The first case was described in 1993. Death was considered to be caused by acute myocardial ischemia from dissection involving the left coronary artery. Further cases have been described where death was thought to originate from increasing hypertension during progressive extension of the dissection followed by a sudden irritation of the subendothelially localized conduction system of the heart. The presented case involves a rapidly fatal aortic dissection in a 64 year old man without any intimal tears and no blood in the dissected aortic wall, although the dissection involved the entire aorta. Death was considered due to myocardial ischemia since the dissection had reached the aortic root and the origins of the coronary arteries.     

主动脉夹层的低场强磁共振成像研究

目的研究主动脉夹层在低场强磁共振SE(自旋回波)序列和GE(梯度回波)序列上磁共振成像(MRI)的特点.材料与方法使用0.3T永磁型MR仪检查了7例主动脉夹层患者,做SE序列(包括T1加权轴位和左前斜位,质子密度/T2加权轴位)和GE序列轴位.盲法分析病变在各序列上的显示情况和MRI表现.结果各序列均能清楚显示主动脉夹层的双腔(真腔和假腔),但以T1加权轴位和左前斜位为优,后者可显示病变的累及范围;显示剥脱的内膜片以GE序列轴位为优,且需时短.结论尽管在显示内膜片破口和假腔内血栓方面不及高场强MR仪,低场强MR仪SE序列T1加权轴位和左前斜位,结合GE序列轴位也可清楚显示主动脉夹层的真假腔、内膜片和病变累及范围;可作为检查主动脉夹层的基本序列.     

Diagnosis of acute thoracic aortic dissection using combined echocardiography and computed tomography.

Acute dissection of the thoracic aorta is a life-threatening emergency requiring a diagnosis which is rapid, accurate and safe, and which will distinguish between dissections involving the ascending and descending aorta. In the absence of any general agreement on the best method of making this diagnosis we studied the use of combined echocardiography and contrast-enhanced computed tomography (CT) to diagnose acute aortic dissection. Over a 3 year period 23 patients were investigated in this way. Aortic dissection was demonstrated in 18 cases, involving the ascending aorta in 15, and the descending aorta alone in three. The diagnosis of aortic dissection was confirmed in 13 patients at surgery, in one at aortography and in one at autopsy. Three patients died without surgery or autopsy being performed to confirm the diagnosis and the subsequently which accounted for their symptoms. This combined approach has proved a valuable and safe means of investigating aortic dissection.     

Endoluminal treatment of aortic dissection

Aortic dissection is most often a catastrophic medical emergency which, if untreated, can be potentially fatal. The intention of therapy in patients with aortic dissection is to prevent aortic rupture or aneurysm formation as well as to relieve branch vessel ischaemia. Patients with aortic dissection are often poor candidates for anaesthesia and surgery and the surgical procedure itself is challenging requiring thoracotomy, aortic cross clamping, blood transfusion as well as prolonged hospital stay in some cases. Operative mortality is especially high in patients with critical mesenteric or renal ischaemia. The past decade has experienced the emergence of a number of interventional radiological or minimally invasive techniques which have significantly improved the management of patients with aortic dissection. These include stent grafting for entry site closure to prevent aneurysmatic widening of the false lumen as well as percutaneous techniques such as balloon fenestration of the intimal flap and aortic true lumen stenting to alleviate branch vessel ischaemia. False lumen thrombosis following entry closure with stent grafts has been observed in 86–100% of patients, whereas percutaneous interventions are able to effectively relieve organ ischaemia in approximately 90% of the cases. In the years to come, it is to be expected that these endoluminal techniques will become the method of choice for treating most type-B dissections and will assist in significantly reducing the number of open surgical procedures required for type-A dissections. The intention of this article is to provide an overview of the current status of these endoluminal techniques based on our own experience as well as on a review of the relevant literature.     

Radiologic evaluation of aortic dissection

The radiologic assessment of patients suspected of having an aortic dissection must be based on an understanding of the treatment options and how these are to be employed in any clinical setting. The appropriate selection and timing of imaging studies is crucial. The diagnosis of dissection must be quickly confirmed, other diseases that mimic dissection must be excluded, and the type and extent of dissection must be established so that appropriate therapy can be instituted. Although computed tomography, magnetic resonance (MR) imaging, and echocardiography greatly enhanced the ability to evaluate the aorta by noninvasive means, aortography remains the examination of choice for defining the vascular anatomy, especially when surgical intervention is considered. MR imaging may become the primary examination for the initial and subsequent evaluation of acute and chronic dissections as MR angiographic techniques improve and changes are made in monitoring equipment to allow the safe examination of acutely ill patients.     

主动脉夹层的MRI诊断

目的：评价MPd对主动脉夹层的诊断价值。方法：回顾性分析7例主动脉夹层的MRI表现。采用Siemens Impact 1．0T CTMR成像仪，行轴位、冠状位及平行主动脉弓斜位扫描，SE序列T1WI、T2WI成像。扫描范围自肺尖至左右髂血管分叉处。结果：按DeBakey分型：Ⅰ型2例，Ⅱ型2例，Ⅲ型3例。按Stanford分型：A型2例，B型5例。MPI表现：直接征象：①主动脉管腔内的内膜片，7例显示内膜片呈线样螺旋状稍高信号；②双腔主动脉，7例显示真腔较假腔小，呈三角形或半圆形，假腔宽大，信号较真腔高；③1例显示内膜破口。间接征象：①主动脉增宽5例；②胸腔积液3例，呈长T1长T2信号，1例腹膜后渗出，表现为肾筋膜增厚；③累及动脉瓣和主要大血管分支，2例主动脉瓣受累，2例累及头臂血管，1例腹腔动脉受累，2例累及肾动脉，2例累及髂血管。受累血管内信号增高，内壁不光整。结论：主动脉夹层具有典型MPI征象。MRI对主动脉夹层的诊断具有较高的敏感性和特异性，是一种无创、安全、有效的检查方法。     

Unusual manifestations of aortic dissection

Two unusual manifestations of aortic dissection, rupture into the main pulmonary artery and rupture into the inferior vena cava, are presented. The latter complication has not been reported previously in the literature. The value of inferior vena caval oximetry to delineate the site of fistulous communication is stressed.     

The contribution of color-coded Doppler in early vascular complications of kidney transplantation

Ultrasound techniques and radionuclide studies are very often used to assess vascularization of renal transplants. Although, in acute tubular necrosis or acute rejection, it is difficult to choose between these two techniques, in 3 recent cases of renal artery thrombosis, we conclude that color coded Doppler is preferable to nuclear medicine or duplex system to diagnose this form of thrombosis.     

Complex thoracic aortic dissection treated by aorto-biiliac bypass and juxta-renal removal of aortic fenestrations

Thoracic aortic dissections are a life-threatening pathology. They occur when there is an intimal tear causing separation of the layers of the aorta. Thoracic aortic dissections can be acute or chronic and depending on the pattern of the dissection can be difficult to treat. No acute dissections are the same, and herein we describe a case of a 62-male presenting with an acute thoracic aortic dissection requiring acute aorto-biiliac bypass and juxta-renal removal of aortic fenestrations.     

CT characteristics of aortic atherosclerotic aneurysm versus aortic dissection

In an attempt to better define criteria for the diagnosis of atherosclerotic aneurysm (AA) and aortic dissection (AD) using CT the scans of 60 documented aortic lesions were reviewed. Hyperdensity of the aortic wall at multiple levels was found to be specific for AD. Central displacement of atheromatous calcification and deformity of the residual aortic lumen were more common in AD than in AA. Peripheral location of aortic wall calcification and a round aortic lumen in cross section were more common in AA than in AD. Central calcification in AA appeared to be associated with a serious short-term prognosis in several cases. A thickened aortic wall of low density was more common in AA than in acute AD, but this relationship was not significant when acute and chronic ADs were considered as a single group. Wall thickness correlated with cross-sectional size of the aortic lesion in AA but not in AD. The mean maximum wall thickness exceeded 1 cm for both AA and AD and was not significantly different between the two; contrary statements have been made in the angiographic literature.     

螺旋CT在主动脉夹层诊断中的临床应用

急性主动脉夹层属危重急症,发病急,预后差,尽管外科手术及药物治疗有长足进步,但围手术期病死率仍很高.应用螺旋CT扫描、螺旋CT血管造影(spiral CT angiography)及影像后处理功能,使图像分辨率明显提高,能够明确主动脉夹层的类型并了解其形态变化,为临床内科及外科制定手术计划提供精确的影像信息,从而减少病死率.本文对22例螺旋CT诊断的主动脉夹层作了回顾性分析,并探讨螺旋CT扫描及SCTA的诊断价值.