Lectin-like oxidized low-density lipoprotein receptor 1 and matrix metalloproteinase expression in ruptured and unruptured multiple dissections of distal middle cerebral artery: case report

Purpose

Oxidized low-density lipoprotein receptor 1 (LOX1) is a critical factor for atherosclerosis in a variety of vascular diseases; however, its major role in cerebral arterial dissecting aneurysm is unclear.

Clinical presentation

We present a case of remarkable contrast of LOX1 expression in ruptured and unruptured multiple middle cerebral artery dissections and discuss the correlation of LOX1 with matrix metalloproteinases (MMPs). A 59-year-old woman presented with subarachnoid hemorrhage associated with left temporal subcortical hematoma. Emergent cerebral angiography demonstrated aneurysmal dilatation at the origin of the left anterior temporal artery (ATA) and occlusion on the distal side of ATA. Infectious aneurysm was excluded. Intraoperative findings showed ruptured dissection of the left ATA and unruptured aneurysmal dilatation of another temporal branch of the left M1 portion. Both lesions were trapped by clips and resected. Histopathological examination confirmed that both ruptured and unruptured aneurysmal dilatations were diagnosed as arterial dissections. Immunohistochemical examination demonstrated remarkable expressions of LOX1, MMP-2, and MMP-9 in hypertrophic media outside the intima in ruptured dissection, on the other hand, those expressions in the intima and inside hypertrophic media in the unruptured dissection.

Conclusions

This is the first report to reveal immunohistochemical findings of LOX1 and MMPs in multiple dissections of MCA. The contrast localization of LOX1 and MMPs might contribute to the fragility of the arterial wall layer of ruptured/unruptured arterial dissections.     

Acute surgery for ruptured dissecting aneurysm of the M3 portion of the middle cerebral artery

A 65-year-old woman presented with a ruptured dissecting aneurysm of the M3 portion of the middle cerebral artery (MCA) manifesting as disturbance of consciousness and motor aphasia. Computed tomography revealed subarachnoid hemorrhage. Emergent angiography demonstrated segmental aneurysmal dilatation of the M3 portion of the left MCA. Infectious aneurysm was excluded. Surgery was performed to prevent repeated hemorrhage from the aneurysm. The lesion was excised and flow to the distal MCA was preserved with an anastomosis of the superficial temporal artery to the MCA. Histological examination confirmed that the aneurysmal dilatation was due to arterial dissection caused by disruption of the internal elastic lamina. Distal dissecting aneurysm may occur in the absence of infectious disease. Such ruptured distal dissecting aneurysm should preferably be treated surgically in the acute stage, immediately after detection of the aneurysm. The parent artery of the proximal and distal sides of the aneurysm should be trapped because of the probable weakness of the arterial wall, and bypass surgery performed to preserve the distal circulation.     

Embolization for aneurismal dilatation associated with ruptured dissecting anterior inferior cerebellar artery aneurysm with preservation of the parent artery: case report

We report a rare case of a ruptured dissecting anterior inferior cerebellar artery (AICA) aneurysm treated by endosaccular embolization with a Guglielmi detachable coil (GDC). An 85-year-old female presented with headache. Computed tomographic (CT) scan showed subarachnoid hemorrhage and intraventricular hemorrhage in the fourth ventricule. Cerebral angiography and 3D-CT angiography revealed an aneurysmal dilatation at the anterior pontine segment of the right AICA with a diagnosis of arterial dissection. The right posterior inferior cerebellar artery (PICA) was absent and the right AICA supplied the territory normally nourished by the right PICA. The aneurismal dilatation was occluded by endosacullar embolization with preservation of the AICA. The distal AICA aneurysm is rare and only seven cases treated with endovascular embolization have been reported. In these, six cases were treated by parent artery occlusion with coil and the subsequent three cases presented with ischemic complications. Only one case was treated by endosaccular embolization with GDC. To our knowledge, this is the second report of the distal AICA aneurysm treated by endosaccular embolization with GDC. Distal AICA aneurysms are briefly discussed while reviewing the literature.     

Spontaneous dissecting aneurysms of anterior and middle cerebral artery associated with brain infarction: a case report and review of the literature

BACKGROUND

Intracranial dissecting aneurysms have been reported with increasing frequency and are recognized as a common cause of stroke. In some reviews and case reports, attempts have been made to compare the outcomes of surgical and medical treatments. However, the appropriate management of dissecting aneurysms in the anterior circulation remains controversial, especially in patients who also manifest cerebral infarction.

CASE DESCRIPTION

A 45-year-old male was diagnosed as having a dissecting aneurysm of the right middle cerebral artery (MCA) with cerebral infarction. In the course of conservative treatment, he developed a new cerebral infarction in the territory of the right anterior cerebral artery (ACA). Repeat cerebral angiograms revealed an increase in the aneurysmal dilatation of the right M2 and the appearance of a segmental dilatation of the right A2. He continued to be treated conservatively and his course was satisfactory. On subsequent angiograms, we observed resolution of the right A2 dissection and no further progression of the dilatation of the right M2.

CONCLUSION

This is the first reported case of simultaneous idiopathic dissecting aneurysms of different major arterial branches in the anterior circulation. Our review of the literature disclosed 36 and 23 cases, respectively, of dissecting aneurysms of the ACA and MCA. Many previously reported patients with these dissecting aneurysms involving subarachnoid hemorrhage (SAH) underwent surgery, which resulted in better outcome. More than half of the patients with ACA and MCA dissecting aneurysms had cerebral infarction. All ACA dissecting aneurysms involving ischemia occurred in the A2 region. The outcomes of both surgical and conservative management were equally satisfactory. On the other hand, in patients with MCA dissecting aneurysms, the area of ischemia frequently involved the M1 region; in these patients, conservative treatment resulted in poor outcomes. Therefore, revascularization distal to the compromised artery should be considered in patients with MCA-dissecting aneurysms who have ischemia. Careful interpretation of serial angiograms and/or magnetic resonance (MR) images is necessary because of the possibility of disease progression. If the aneurysmal size increases or there is progression of ischemic symptoms in the course of conservative treatment, surgery must be urgently evaluated.     

Subarachnoid hemorrhage in the presence of both intracranial dissecting and saccular aneurysms--two case reports

Two patients presented with subarachnoid hemorrhage (SAH) associated with both intracranial dissecting and saccular aneurysms. Case 1, a 48-year-old woman, had a saccular aneurysm of the right internal carotid artery and dissecting aneurysms of the bilateral vertebral arteries. Case 2, a 52-year-old man, had three saccular aneurysms in the anterior circulation and a dissecting aneurysm of the unilateral vertebral artery. A saccular aneurysm was responsible for the SAH in both patients. Ruptured saccular aneurysms were treated with surgical clipping and unruptured dissecting aneurysms remained untreated. SAH recurred due to bleeding from an untreated dissecting aneurysm 4 days after the initial SAH in Case 1. Triple-H therapy, which causes increased hemodynamic stress, was not administered for symptomatic cerebral vasospasm after SAH in Case 2, because of the risk of bleeding from the untreated dissecting aneurysm, and the patient suffered cerebral infarction. The risk factors for this rare association are unclear, but both patients were smokers and had hypocholesterolemia including low apolipoprotein E levels. The clinical management of patients with SAH and both dissection and saccular aneurysms is complicated. Asymptomatic dissecting aneurysm has a benign clinical course in general, but hemodynamic stress related to stroke may induce abrupt development of dissecting aneurysms. Prophylactic obliteration during the acute stage of SAH may provide better outcomes if the unruptured dissecting lesion appears as obvious aneurysmal dilatation or pearl-and-string sign and is safely treatable with endovascular trapping.     

Dissecting aneurysm of the anterior choroidal artery: angiographical and MR imaging findings

BACKGROUND: Intracranial dissecting aneurysms are relatively rare. We present a rare case of a dissecting aneurysm originating from the anterior choroidal artery; this is the first reported case.CASE DESCRIPTION: A 42-year-old man suffered sudden onset of right hemiparesis and dysarthria. Computed tomography on admission revealed a small low density area in the posterior limb of the internal capsule. MR imaging revealed aneurysmal dilatation of the anterior choroidal artery, and angiography revealed aneurysmal dilatation and stasis of dye in the venous phase at the anterior choroidal artery, which resolved in the chronic stage.CONCLUSION: We describe a rare case of a dissecting aneurysm of the anterior choroidal artery. The radiological findings were characteristic of dissecting aneurysms in spite of the rare location.     

Postoperative discitis due to Propionibacterium acnes: a case report and review of the literature

BACKGROUND: A rare case of a growing dissecting aneurysm, which was located at the horizontal (A1) segment of the anterior cerebral artery (ACA), is reported. CASE DESCRIPTION: A 53-year-old woman experienced left hemiparesis and alien hand syndrome. A computerized tomography scan showed an infarction in the right frontal lobe, and cerebral angiography revealed a false lumen and intimal flap at the A1 segment of the ACA. Magnetic resonance angiography demonstrated that the stenosis progressed 6 months later and improved 1 year later. Cerebral angiography showed a saccular-like aneurysm 2 years later. The surgery was planned for prevention of aneurysmal rupture. The aneurysm, which was cocoon shaped, was exposed surgically and was resected. Histological examination of the aneurysm showed arterial dissection. The postoperative course was uneventful without additional neurological deficits. CONCLUSION: This is the first case report of A1 dissecting aneurysm presenting with an ischemic event in the literature. The sequential change of the configuration was curious to develop aneurysmal dilatation in 2 years. Long-term follow-up is necessary even after disappearance of the arterial dissection.     

Serial angiographical changes of a ruptured dissecting vertebral aneurysm

A 54-year-old woman presented a subarachnoid hemorrhage from a ruptured dissecting aneurysm on the right vertebral artery. A right vertebral angiogram revealed a fusiform dilatation distal to the right posterior inferior cerebellar artery and "pseudo lumen" was observed in a delayed arterial phase. Conservative treatment was carried out, and the patient condition gradually improved. An angiographical examination for planned endovascular treatment 46 days after the onset, revealed the normalization of the formerly dilated caliber of the right vertebral artery with only a minor luminal irregularity. However, 83 days after the onset, right vertebral angiogram showed reappearance of the fusiform dilatation. The right vertebral angiogram obtained 204 days after the onset showed that the dilated segment of the dissecting aneurysm had become normalized to a slight degree. The serial angiographical changes of the dissecting site might have been due to regression and organization following transient thrombosis of intramural hematoma. Such drastic changes within a short period have not been reported yet. In conclusion, careful repeated follow-up is recommended in monitoring aneurysmal formation during the early to chronic phase after rupture of a dissecting aneurysm. The repetition of angiography is important, because later, if angiography has been performed only once, aneurysmal dilatation may be overlooked. One has to be aware of such changes, because such changes may alter the clinician's decision about treatment, as they did in our case.     

Aneurysm growth and enlargement of pre-aneurysmal lesions

Three patients with cerebral aneurysms newly growing and enlarging for 2 to 10 years are reported. Case 1, a 54-year-old woman, had subarachnoid hemorrhage due to rupture of an intracranial aneurysm, growing from a small residual aneurysmal neck on the left internal carotid artery 10 years after the repair of the aneurysm. Case 2, a 63-year-old man, had a junctional dilatation on the left internal carotid-posterior communicating artery, developing into ruptured aneurysm about 10 years after the first hemorrhage. Case 3, a 52-year-old man, had multiple aneurysms on the bilateral bifurcations of middle cerebral arteries and left anterior cerebral artery-frontopolar artery junction. Angiography 2 years after the repair of the aneurysms revealed the new growth of a small aneurysm on the anterior cerebral artery at the junction of the fronto-orbital artery, developing from a localized vascular dilatation which had been recognized by the preoperative angiography. The existence of pre-aneurysmal lesions in arterial wall and the addition of hemodynamic impingement were thought to be one of the precipitating factors of aneurysmal formation. The pre-aneurysmal lesions in our study are as follows; a small part of thin wall of residual aneurysmal neck, a junctional dilatation, and a small evagination of arterial wall. It is necessary to discriminate a junctional dilatation and a small evagination of arterial wall from a small aneurysm with observation from multiple directions by the preoperative angiographic study. Our observations suggest that preaneurysmal lesions of the cerebral artery may develop into aneurysm and rupture, and hence the follow-up angiography is recommended for the cases with a preaneurysmal lesion or a small aneurysm for many years.     

Huge popliteal arterial aneurysms in Behçet's syndrome: is ligation an alternative treatment?

Beh?et's syndrome is a multisystemic disease characterized by relapsing uveitis, oral and genital ulcerations, and vascular system involvement. The vascular involvement is seen as venous occlusion, arterial occlusion, and aneurysm formation in this disease, and the surgical treatment of a Beh?et's aneurysm has technical difficulties. In this report, we suggest that the huge popliteal artery aneurysm in Beh?et's syndrome can be treated by ligation of the popliteal artery. A 58-year-old male patient was admitted to our clinic because of an infrapopliteal great mass at the left leg. Color Doppler ultrasonography and arteriography revealed a 71 x 54 mm aneurysmal dilatation at the distal popliteal artery. Surgery did not reveal any suitable arterial formation for bypass to the distal area of the popliteal artery and tibial arteries. For this reason, we applied ligation of aneurysmal dilatation at the distal popliteal artery. The patient tolerated the operation well and had no signs of ischemia during the postoperative period. In conclusion, especially in aneurysm of arteries such as the popliteal artery, which has critical importance for maintaining distal perfusion, ligation may be a treatment method if there are no other alternatives.     

Dissecting aneurysm of the anterior cerebral artery requiring surgical treatment--case report

A 45-year-old male presented with spontaneous dissecting aneurysm in the anterior cerebral artery manifesting as headache persisting for several days and speech disturbance. Neurological and laboratory examinations showed no abnormalities. Magnetic resonance imaging revealed infarction in the right cingulate gyrus. Angiography revealed occlusion of the right A2. Repeat angiography 8 months later showed a saccular aneurysm had developed. The interhemispheric approach exposed the aneurysm at the junction between the right frontopolar artery and the pericallosal artery. The aneurysm was fusiform due to the right A2 dissection. The aneurysm was trapped and resected. One month after the operation, the patient was discharged without neurological deficits. Cases of dissecting aneurysms in the anterior cerebral artery with ischemic onset are usually treated conservatively. Cases requiring surgery include those due to trauma, growing aneurysms, giant aneurysms, and uncontrolled hypertension. Some dissecting aneurysms of the distal anterior cerebral artery require only resection without bypass surgery.     

Autopsied case of an extracranial internal carotid artery dissecting aneurysm

An autopsy case of extracranial internal carotid artery (ICA) dissecting aneurysm due to atherosclerosis was reported. A 74-year-old man was admitted to our hospital with the chief complaints of hoarseness and a pulsatile mass below the left mandibular angle. Neurological examination showed no obvious deficits except left recurrent laryngeal nerve palsy. Angiography revealed narrowing of the original segment of left ICA with dissection and aneurysmal dilation at the level of C3 vertebra. Seven days after admission, the patient had a sudden onset of consciousness disturbance. The second angiography showed no obvious changes compared with the first findings except slight narrowing in the distal portion above the aneurysmal dilation. The possible mechanism was thought to be recanalization following transient occlusion of the left ICA caused by extension of dissection or intracranial embolism due to a thrombus within the aneurysm. He was managed conservatively, but unfortunately he died of pneumonia. Macroscopic autopsy showed that the aneurysm was fusiform. Histologically, it demonstrated dissection of the hematoma between the media and adventitia layer. Hemorrhage in the atheromatous plaque with disruption of the elastic lamina were observed along with severe degenerative changes of the intima, media and, in part, adventitia layer due to atherosclerosis. In addition, a dissecting aneurysm of the right iliac artery and severe arteriosclerosis were observed in the systemic arteries. On the basis of these findings, the dissecting aneurysm presumably developed after disruption of a weak portion of the atherosclerotic wall, where intraplaque hemorrhage occurred earlier. We suggest that atherosclerosis be regarded as one of the pathogenic factors capable of causing dissecting aneurysm of the extracranial ICA in elderly patients.     

Middle cerebral artery dissecting aneurysm causing intracerebral hemorrhage 4 years after the non-hemorrhagic onset: a case report

BACKGROUND: We report a case of dissecting middle cerebral artery (MCA) aneurysm causing intracerebral hemorrhage 4 years after the non-hemorrhagic onset. CASE DESCRIPTION: A 30-year-old male was diagnosed with an unruptured dissecting MCA aneurysm after a severe pulsating headache in August 1993. Angiography revealed dilatation of the distal portion of the temporo-occipital artery. During 2 years of follow-up, there were no significant changes on magnetic resonance imaging. In August 1997, he became comatose because of massive intracerebral hemorrhage caused by a dilated fusiform dissecting aneurysm. Emergency surgery and postoperative mild hypothermia resulted in full recovery. CONCLUSION: To date only 30 cases of dissecting MCA aneurysm have been reported and for unruptured aneurysms, surgical intervention was not chosen. However, the present case strongly suggests that long-term follow-up is necessary in patients with unruptured dissecting aneurysms of the anterior circulation, especially those with ectatic components.     

Endovascular treatment of ruptured axillary and large internal mammary artery aneurysms in a patient with Marfan syndrome

Marfan syndrome is an autosomally inherited disorder affecting the synthesis of connective tissues. Vascular manifestations of Marfan syndrome include aneurysmal dilatation of the aortic root, aortic dissection, and rupture. Peripheral aneurysms are mostly reported in the iliac, femoral, and subclavian arteries. We report a Marfan patient with a ruptured axillary artery aneurysm and a large left internal mammary artery aneurysm. The axillary aneurysm was successfully excluded using covered stent grafts, and the left internal mammary artery aneurysm was effectively coiled. Duplex ultrasound imaging at 4 months and computed tomography at 9 months demonstrated complete thrombosis and exclusion of both aneurysms with patent subclavian-axillary stent grafts.     

A dissecting aneurysm of the posterior inferior cerebellar artery was reduced spontaneously during conservative therapy: case report

We report here a case of a patient with a dissecting aneurysm of the anterior medullary segment of the posterior inferior cerebellar artery (PICA) which presented with Wallenberg's syndrome. A 32-year-male presented with an unusual case of Wallenberg's syndrome due to a dissecting aneurysm of the PICA manifesting as a sensation of heaviness in the occipital region and vertigo. The occipital symptoms persisted and vertigo and vomiting developed after 6 days. Numbness developed on the left side of the patient's face, and hyperalgesia on the right side of the body. The diagnosis of Wallenberg's syndrome was based on the above findings. MRI revealed infarction of the lateral aspect of the medulla oblongata and MR angiography revealed dilatation in the proximal portion of the left PICA. Digital subtraction angiography revealed that the left vertebral artery was essentially normal, but there was a spindle-shaped dilatation in the proximal portion of the left PICA. We carried out conservative therapy at the patient's request and 3D-CTA revealed that the dissecting aneurysm was markedly reduced in size seven months after the onset. Dissecting aneurysms of the intracranial posterior circulation have been shown to be less uncommon than previously thought. However, those involving the PICA without involvement of the vertebral artery at all are extremely rare. The natural history of the dissecting PICA aneurysm was unknown, and the indication for surgical treatment of such aneurysms remains controversial. Management options are conservative treatment, open surgical treatment including wrapping, trapping, and resection with reconstruction, but almost all of the patients underwent radical treatment to prevent rupture of the aneurysm. However we had no knowledge of the risk of rupture of a PICA dissecting aneurysm presenting with ischemic symptoms. We have reviewed the well-documented 15 cases of dissecting aneurysms of the PICA reported in the literature and we discuss the management of the dissecting PICA aneurysm presenting with ischemic symptoms.     

Case of spontaneous bilateral VA dissecting aneurysm presenting with SAH

We report a case of bilateral vertebral artery (VA) dissecting aneurysm presenting subarachnoid hemorrhage (SAH). It was difficult to decide which side was responsible for SAH because the patient's symptom and head CT suggested that the left VA aneurysm had ruptured, but angiography and MRA showed an irregular pearl and string sign on the right side. He was successfully treated by trapping of the right VA dissecting aneurysm and we confirmed by intraoperative evaluation that the right VA dissecting aneurysm had ruptured. The left unruptured aneurysm decreased its size spontaneously. In the treatment of the bilateral VA dissecting aneurysms, angiography needs to be performed over and over again because contralateral unruptured aneurysm may grow or rupture due to increased hemodynamic stress. Various combinations of direct sugery with or without arterial reconstruction and endovascular treatment should be considered when treating bilateral VA dissecting aneurysms.     

Giant, fusiform and dissecting aneurysms at the vertebro-basilar junction--report of five cases and their clinical pathophysiological aspects

Five cases of giant, fusiform, and dissecting aneurysms of the vertebro-basilar junction, in which direct surgical treatment was not feasible, are reported. Their initial symptoms were as follows: 3 subarachnoid hemorrhages (2 fusiform aneurysms, 1 giant aneurysm), 1 mass sign (giant aneurysm), and 1 ischemic sign (dissecting aneurysm). In two patients, one with a giant and one with a dissecting aneurysm, preoperative proximal vertebral occlusion was carried out by inflated balloon for 30 to 100 minutes, under observation of clinical signs and measurement of distal arterial pressure. This catheter technique with an inflated balloon provides the means to assess the effect of vertebral artery occlusion in the alert patient, and to determine if occlusion is tolerated or not. In one case with a giant aneurysm, the proximal vertebral artery was occluded extracranially with no complications and no recurrent subarachnoid hemorrhage for 1 year. The other four patients (1 thrombosed giant aneurysm, 2 fusiform aneurysms, 1 dissecting aneurysm) whose contralateral vertebral arteries were hypoplastic, and who refused to operation, were treated conservatively for 6 months to 6 years. Their outcomes were better than expected, with no recurrent subarachnoid hemorrhage nor aggravation of clinical symptoms except for the one case with a dissecting aneurysm whose deterioration was presumed attributable to late cerebellar cortical atrophy.     

Endovascular coil trapping for ruptured vertebral artery dissecting aneurysms by using double microcatheters technique in the acute stage

Summary ?Background. In the treatment of vertebral artery (VA) dissecting aneurysms, only proximal occlusion of the VA does not necessarily prevent rerupture. We evaluated the efficacy of coil trapping for the ruptured VA dissecting aneurysms using the double microcatheters technique. Methods. We treated 11 patients who presented with subarachnoid haemorrhage (SAH) due to rupture of a VA dissecting aneurysm which did not involve the posterior inferior cerebellar artery at the site of dissection. All patients tolerated the balloon occlusion test. Within 3 days of the SAH, the dissection site was trapped with a Guglielmi detachable coil (GDC) using the double microcatheters technique. The proximal and distal sites of the dissecting aneurysm were embolized simultaneously. Findings. GDC trapping at the affected site was successful in all 11 patients. Radiographic findings showed complete occlusion of the dissection site and patency of the unaffected artery. Although one patient experienced transient dysphagia, there were no major complications. Interpretation. The double microcatheters technique is effective for coil trapping of ruptured VA dissecting aneurysms in selected patients. The risks posed by this simple technique are minimal, even in the acute stage. Published online May 26, 2003     

Antegrade recanalization of a completely embolized vertebral artery after endovascular treatment of a ruptured intracranial dissecting aneurysm. Report of two cases

Occlusion of the parent artery is a traditional method of treatment of unclippable cerebral aneurysms. Surgical or endovascular occlusion of the parent artery proximal to the aneurysm has been recommended for the treatment of dissecting aneurysms located in the vertebrobasilar circulation. Nevertheless, occlusion of the parent artery may not result in permanent exclusion of the aneurysm from the systemic circulation because, occasionally, postoperative rebleeding occurs after proximal occlusion. Alternatively, endovascular occlusion of the affected site, including the aneurysmal dilation, and parent artery, is a safe and reliable treatment for dissecting aneurysms. The authors present two rare cases of ruptured vertebral artery (VA) dissecting aneurysms that were treated by endovascular occlusion of the affected site including the aneurysm and parent artery by using Guglielmi detachable coils. In both cases the VA recanalized in an antegrade fashion during the follow-up period. Based on these unique cases, the authors suggest that a careful angiographic follow up of dissecting aneurysms is required, even in patients successfully treated with endovascular occlusion of the affected artery and aneurysm.     

Diagnosis and treatment of vertebral aneurysms

The intracranial vertebral artery and its branches are a common site of aneurysms in the posterior fossa. Ninety-four aneurysms in 86 patients were analyzed for their clinical manifestation, diagnosis, and treatment. There were three distinct varieties of aneurysm in this group: 56 (60%) saccular aneurysms, 26 (28%) dissecting aneurysms, and 12 (13%) atherosclerotic fusiform aneurysms. Of the 26 dissecting aneurysms, 81% bled and 24% of these rebled. None of the atherosclerotic fusiform aneurysms bled. Angiographic differentiation between dissecting aneurysms and atherosclerotic fusiform aneurysms was difficult. The dissecting aneurysms were characterized by a "narrowed segment" proximal and/or distal to a "fusiform dilatation" of the affected artery and by the presence of contrast medium in the intramural false lumen until the late phase. Poor postoperative outcome and the lateral medullary syndrome were seen only in dissecting aneurysms. Small atherosclerotic fusiform aneurysms seemed to be benign lesions that do not require any surgical treatment.