True aneurysms

Endotension (or type V endoleak) corresponds to continued aneurysm expansion in the absence of a confirmed endoleak [12, 13], The expansion of the aneurysm in a type V endoleak may be due to an undiagnosed endoleak, presumably with very slow flow and suboptimal imaging (e.g. no delayed helical CT acquisition). Endotension has been reported up to 18% in [14] a study evaluating the significance of endotension in 658 patients. The authors demonstrated that endotension is rare and concluded that it may represent missed endoleak rather than true aneurysm expansion in the absence of perigraft flow [15]. 

AAAs present in three different types or shapes. Fusiform aneurysms, the most typical, are mostly symmetrical bulges that occur around the entire circumference of the aorta. These are sometimes referred to as false aneurysms or pseudoaneurysms, because layers of the wall of the aorta are missing (as opposed to the presence of all three layers in a true aneurysm). An aortic dissection, on the other hand, is when blood penetrates the inner layer of the aortic wall, and flows between the layers, similar to delamination. This typically occurs in the thoracic region of the aorta, but can sometimes occur in the abdominal region. Figure 21.3 shows these various types of aneurysms. 

Classification of intracranial aneurysms may be based on morphology, size, location and etiology. The majority of intracranial aneurysms are true aneurysms containing all layers or components of the normal vessel wall. In contrast, in false aneurysms or pseudoaneurysms, the vascular lumen does not enlarge, although the external diameter of the abnormal segment may be increased. These aneurysms are rare within the skull. 

Iatrogenic lesions tend to be simple traumatic disruptions of the artery, so unlike true aneurysms, the... 

The arterial wall is composed of three layers. The outer serosal covering is the adventitia, the muscular middle layer is the media, and the inner lining is the intima. True aneurysms are distinguished from false or pseudoaneurysms based on which layers of the arterial wall are present in the aneurysm itself. In order to classify an aneurysm as being true, it must be comprised of all three layers. Pseudoaneurysms have any combination less than all three of the arterial wall components. 

Feijoo-Cano C Giant true aneurysm of the radial artery following ligation of an arteriovenous fistula for haemodialysis. Neffologia 2012 32 404M06. 

Aneurysms may complicate 2-10% of all types of VA [14]. These may be false aneurysms (also called pseudoaneurysms from the Greek word pseudos false) and true aneurysms caused by degeneration and subsequent dilatation of the... 

True aneurysms can be repaired with aneurysmorrhaphy (fig. 4), where the excess sac of the aneurysm is resected, and a new autogenous access is reconstructed by plicating the excess free wall [17]. 

PJ is a 60-year-old woman with a history of an abdominal aortic aneurysm who is taking niacin for her dyslipidemia. Her LDL-C is 120 mg/dL, so a statin is added to her therapy. Which of the following are true for statins ... 

Fig.7.9a,b. A 52-year-old woman with a recent history of gall stone pancreatitis was admitted with further abdominal pain. A CECT scan suggested an aneurysm of uncertain origin. Angiography revealed a true (Type la) aneurysm of an aberrant right hepatic artery (a). CECT had revealed a patent portal vein and so proximal and distal coil embolization was performed (b). There were no further complications and the patient is alive and well at 36 months... 

The same holds true for the visualization of the abdominal aorta and for stent graft planning and for post-operative control for endo-leakage (Bartolozzi et al. 1998). Prior to surgery, CTA may be able to display the origin of the renal arteries and the distance from the abdominal aneurysm, as well as the course of the iliac arteries. 

As outlined by Houdart et al. (1993), the depiction of intranidal aneurysms is difficult it is often performed at the time of superselective angiography. Moreover, true arterial intranidal aneurysms have to be distinguished from pseudoaneurysms, which are at the point of rupture of the nidus or of the venous drainage. 

Thus, we can postulate with Berenstein and Lasjaunias (1992) that intranidal aneurysms represent a weakness of the angioarchitecture and should influence treatment strategy. This is prohahly also true for other associated aneurysms. 

Intracranial aneurysms do not fall precisely into the category of true vascular malformations they are usually acquired. However, we included them because any neuroradiologist with an interest in vascular malformations and/or endovascular therapy clearly expects this entity to be covered extensively... 

The course of infectious aneurysms is unpredictable. Under antibiotic or antimycotic therapy they may shrink, or completely disappear. However, enlargement during treatment has also been reported (Brust et al. 1990). Septic aneurysms can be obliterated surgically or by endovascular treatment (Chapot et al. 2002 Phuong et al. 2002 Steinberg et al. 1992). The theoretical assumption that implantation of foreign material - like platinum coils - into an infectious lesion might worsen the problem is not true for infectious intracranial aneurysms. Mortality due to rupture of bacterial cerebral aneurysms is reported to be up to 60% (Barrow and Prats 1990 Bohmfalk et al. 1978 Clare and Barrow 1992). 

Most arterial aneurysms arise at the bifurcation of major arteries, and this is also true for the intracranial location. Around 85% of all intracranial aneurysms originate from the anterior circulation. The most common location (30%-35%) is the anterior communicating artery (Acorn). However, many of these so-called Acorn aneurysms do have their origin at the A1/A2 junction of the anterior cerebral artery and do not involve the anterior communicating artery. Internal carotid and posterior communicating artery aneurysms account for 30% and middle cerebral artery (MCA) bifurcation aneurysms for 20%. Around 15% of intracranial aneurysms arise at the vertebrobasilar circulation. Half of them develop at the basilar tip (with various degrees of involvement of the PI segments) and the other 50% from other posterior fossa vessels. Aneurysms of the anterior inferior cerebellar artery (AICA) and vertebral artery (VA) aneurysms without involvement of the VA-PICA junction or the vertebrobasilar site are extremely rare. 

The majority of posterior communicating artery (Pcom) aneurysms arise from the ICA at the origin of the Pcom. True Pcom aneurysms are rare and might be more difficult to catheterize. About 30%-40% of... 

The main technical challenge of the endovascular procedure depends on the shape of the aneurysm and not on its location. But since the introduction of very flexible neurostents and the development of different coil designs most of the basilar tip aneurysms are now treatable with the endovascular approach. This is also true for broad-based aneurysms which... 

It is clear that in case of true positive findings, such as the early diagnosis of abdominal aortic aneurysm or renal cell carcinoma, patients will benefit from incidental extracolonic findings. 

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