Dissecting aneurysms at the A1 segment of the anterior cerebral artery--two case reports

Two rare cases of dissections which involve the anterior cerebral artery (ACA) are reported. A 58-year-old woman presented with a ruptured dissecting aneurysm manifesting as sudden onset of severe headache and consciousness disturbance followed by aphasia, right hemiparesis, paresis of the left lower extremity, and choreoathetotic movements of the upper arms and face. Computed tomography and angiography revealed subarachnoid hemorrhage due to a dissecting aneurysm at the left A1 segment. The dissecting aneurysm was trapped surgically on the day of onset. Her neurological deficits disappeared within a month. A 39-year-old woman experienced continuous dull headache from the day before onset, and then suffered right hemiparesis. Magnetic resonance (MR) imaging revealed cerebral infarction at the left globus pallidus. Angiography and MR imaging revealed a dissecting aneurysm at the left A1 segment and occlusion of the left Heubner's artery. She received conservative treatment and her neurological findings were improved. Dissections or dissecting aneurysms involving the ACA can be classified into three types: Extension of a dissection to the ACA from the internal carotid artery, dissection at the A1 segment, and dissection at the A2-A4 segments. These types of dissection have distinct uniform clinical features.     

Dissecting aneurysm of the anterior temporal artery: case report

A 65-year-old woman presented a rare dissecting aneurysm of the anterior temporal artery (ATA) manifesting as headache. Computed tomography and magnetic resonance imaging revealed a mixed-density mass in the horizontal segment of the middle cerebral artery. Emergent angiography demonstrated aneurysmal dilatation and a thrombosed mass in the sylvian fissure. Infectious aneurysm was excluded. She underwent emergent surgery to reduce the risk of repeated infarction and hemorrhage. The distal side of the ATA manifested occlusive changes suggestive of arterial dissection. The proximal side of the ATA was ligated and the lesion was excised. Histological examination confirmed that the aneurysmal dilatation was attributable to arterial dissection due to disruption of the internal elastic lamina. Distal dissecting aneurysms may occur in the absence of infectious disease. We recommend that ruptured distal dissecting aneurysms be treated surgically in the acute stage immediately after detection.     

Dissecting aneurysm of the anterior cerebral artery with persistent pearl & string sign on cerebral angiograms over a period of eight years]

We present a rare case of a dissecting aneurysm of the left anterior cerebral artery (ACA) with persistent pearl & string sign on cerebral angiograms over a period of 8 years. A 43-year-old woman with disturbance of consciousness and right sided hemiparesis was conservatively treated. Computed tomographic (CT) scan revealed a low-density area in the left frontal lobe. Initial angiography, which was performed at 6 months after the onset, showed a pearl & string sign at the A2 portion of the left ACA. After 8 years, repeat angiography again showed persistent pearl & string sign at the same portion of the left ACA. We discussed the changes in findings usually obtained in cerebral angiography concerning dissecting aneurysms in ACA.     

Subarachnoid hemorrhage in a case of segmental arterial mediolysis with coexisting intracranial and intraabdominal aneurysms

The authors report the rare case of a 58-year-old man with segmental arterial mediolysis (SAM) with associated intracranial and intraabdominal aneurysms, who suffered subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. This disease primarily involves the intraabdominal arterial system, resulting in intraabdominal and retroperitoneal hemorrhage in most cases. The patient presented with severe headache and vomiting. The CT scans of the head revealed SAH. Cerebral angiography revealed 3 aneurysms: 1 in the right distal anterior cerebral artery (ACA), 1 in the distal portion of the A(1) segment of the right ACA, and 1 in the left vertebral artery. The patient had a history of multiple intraabdominal aneurysms involving the splenic, gastroepiploic, gastroduodenal, and bilateral renal arteries. He underwent a right frontotemporal craniotomy and fibrin coating of the dissecting aneurysm in the distal portion of the A(1) segment of the right ACA, which was the cause of the hemorrhage. Follow-up revealed no significant changes in the residual intracranial and intraabdominal aneurysms. An SAH due to SAM with associated multiple intraabdominal aneurysms is extremely rare. The authors describe their particular case and review the literature pertaining to SAM with associated intracranial and intraabdominal aneurysms.     

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.     

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.     

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.     

Multiple spontaneous dissecting aneurysms of the anterior cerebral and vertebral arteries

A 50-year-old woman presented with rare multiple dissecting aneurysms that appeared first in the anterior cerebral artery (ACA) and shortly afterwards in the vertebral artery (VA). She initially suffered sudden motor weakness in the left lower limb due to acute brain infarction. Angiography revealed diffuse string sign in the right ACA. Conservative treatment resulted in resolution of the deficits. Follow-up angiography performed 1 year later revealed recovery of the ACA stenosis. Fourteen days later, she complained of sudden headache and became comatose. Computed tomography showed diffuse subarachnoid hemorrhage. Angiography revealed a new right VA dissecting aneurysm involving the posterior inferior cerebellar artery (PICA). The orifice of the dissection was not apparent in the operative field and the dissection extended to the median. The patient underwent extracranial right VA ligation, clipping of the proximal PICA, and revascularization between the right occipital artery and distal PICA. Her postoperative course was uneventful and she was discharged without neurological deficits. VA dissecting aneurysms involving the PICA without evident orifice or extending over the median can be treated by extracranial ligation with clipping of the PICA, followed by revascularization.     

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.     

A rare case of cerebral aspergillus aneurysm at the site of temporary clip application

Anterior communicating artery aneurysm was shown in a 48-year-old man who had suffered from subarachnoid hemorrhage (SAH) by cerebral angiography. Right pterional approach was performed on the 40th day after SAH. Premature ruptured occurred during aneurysmal manipulation and temporary clip (Scoville clip) was placed at the middle of the right A1 segment for fifteen minutes. the anterior communicating artery aneurysm was successfully clipped and postoperative course was uneventful. But, four days after the operation, the patient fell into coma following generalized tonic convulsion. Lumbar puncture showed fresh SAH. Consciousness recovered gradually to a lethargic state. A newly formed berry aneurysm was revealed on the righ A1 segment at the site of the temporary clip application by cerebral angiography performed on the seventh day after aneurysmal surgery. Second attack occurred on the 12th postoperative day and the patient died on the 16th day after the operation. Postmortem findings disclosed massive subarachnoid and intraventricular hemorrhage from the ruptured aneurysm at the right A1 segment. Microscopic examination of the aneurysm and the right A1 segment. microscopic examination of the aneurysm and the right A1 segment showed the extensive destruction of the artery and massive proliferation of aspergillus in the arterial wall which was prominent of its outer layer. The mechanism of the formation of the new aneurysm in this case was considered as follows: the arterial wall was primarily damaged by the temporary clip and was weakened rapidly by the invasion of aspergillus, probably producing thrombosis of the vast vasorum, hemorrhage, and necrosis in it.     

Dissecting aneurysms of the anterior cerebral artery and accessory middle cerebral artery. Case report

A 66-year-old woman presented with dissecting aneurysms of the anterior cerebral artery (ACA) and accessory middle cerebral artery (MCA) manifesting as subarachnoid hemorrhage but without radiological evidence of the dissecting aneurysms. Intraoperative observation revealed that the vessel walls were dark purple in color, a typical finding of dissecting aneurysm. The abnormal A1 segment was trapped and the dissecting aneurysm of the accessory MCA was wrapped. In the case of SAH of unknown origin, dissecting aneurysm should always be kept in mind even if the angiogram does not show any abnormal finding. This is the first reported case of dissecting aneurysm of the accessory MCA.     

Dissecting aneurysm of the anterior cerebral artery with later development of collateral circulation: a case report

Intracranial dissecting aneurysm (DA) is much less frequent than berry aneurysm. Such dissection involves mostly the vertebral and basilar arteries, followed by the internal carotid and middle cerebral arteries. DA of the anterior cerebral artery (ACA) is relatively rare and little is known about its natural Development. Only 23 cases have been reported previously. Our present patient, a 44-year-old man, suddenly developed paresis of the left leg while bathing. Diffusion magnetic resonance imaging indicated an area of high signal intensity in the territory of the ACA. Angiography on day 3 following onset showed a DA involving the left A2 segment. Antiplatelet therapy was administered. Further luminal narrowing in the lesion was demonstrated by repeat angiography on day 17. Occlusion of the distal A2 segment was demonstrated together with sufficient collateral supply on day 41. Symptoms resolved completely. DA of the ACA usually presents with ischemic attacks. Its etiology remains uncertain, and its natural course is unclear. Surgical intervention is recommended for patients with intracranial hemorrhage, while non surgical therapies have achieved good outcomes in ischemic cases.     

Giant aneurysm of the pericallosal artery causing acute subdural hematoma--case report

A 66-year-old female presented with a very rare giant aneurysm of the distal pericallosal artery. She lost consciousness and was admitted. Computed tomography demonstrated a subdural hematoma over the left cerebral convexity and a mass in the frontal lobe. Cerebral angiography disclosed a giant aneurysm located on the distal segment of the right pericallosal artery. The subdural hematoma was removed and the aneurysmal neck was clipped, but she died 15 days after the operation. Autopsy found the giant aneurysm (33 x 30 x 27 mm) on the distal segment of the right pericallosal artery. Highly atheromatous changes were recognized in part of the aneurysmal wall, the arteries near the circle of Willis, and the distal anterior cerebral artery (ACA) adjacent to the aneurysm. There were no anomalous vessels such as azygos ACA. Giant aneurysms situated beyond the genu of the corpus callosum are extremely rare. Atherosclerosis was probably a major etiological factor in this case.     

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.     

Ruptured aneurysm arising from the proximal end of an azygos anterior cerebral artery--case report

A 59-year-old woman presented with subarachnoid hemorrhage. Conventional angiography and three-dimensional computed tomography (3-D CT) angiography showed a saccular aneurysm at the junction of the azygos anterior cerebral artery (ACA) and the left A1 segment. This aneurysm was associated with a fenestration of the right hypoplastic A1 segment. The aneurysm neck was completely clipped, preserving the azygos ACA and other perforators. Aneurysm of the azygos ACA is almost always located at the distal bifurcation, and rarely at the proximal end. Proximal azygos ACA aneurysm can mimic anterior communicating artery aneurysm. Therefore, accurate preoperative diagnosis is critical using 3-D CT angiography as well as conventional angiography, and close follow up of patient is necessary to monitor for development of a de novo aneurysm at the distal bifurcation of the azygos ACA.     

Dilated outer diameter of the dissected artery: acute bilateral anterior cerebral artery dissection evaluated by repeat magnetic resonance cisternography. Case report

A 42-year-old male patient presented with an anterior cerebral artery (ACA) dissection manifesting as sudden onset of severe headache. Initial computed tomography revealed faint subarachnoid hemorrhage in the frontal region. Initial angiography showed tapering stenosis at the A(2) segment of right ACA. The patient was admitted to our hospital and treated conservatively. Magnetic resonance (MR) imaging and angiography did not detect intramural hematoma, intimal flap, or double lumen at the stenotic right A(2) segment. The ACA dissection was difficult to confirm based on the findings on day 0. ACA dissection was confirmed by improvement of the right ACA stenosis on follow-up angiography on day 14. On the other hand, MR cisternography revealed a fusiform dilatation of the vascular outer contour at the right A(2) on day 0, which had resolved on day 14. Cerebral angiography and MR cisternography similarly suggested asymptomatic contralateral (left) A(2) dissection on day 14. Fusiform dilatation of the vascular outer contour at the affected segment on MR cisternography may be indicative of arterial dissection in the acute phase.     

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.     

Serial angiography and endovascular treatment of dissecting aneurysms of the anterior cerebral and vertebral arteries. Case report.

This 47-year-old man was admitted to the hospital with disturbance of consciousness due to subarachnoid hemorrhage caused by a ruptured dissecting aneurysm of the left anterior cerebral artery (ACA). Conservative treatment resulted in improvement in the patient's consciousness; however, repeated rupture occurred during the chronic stage. Endovascular coil embolization of the parent artery was successful. Serial angiography demonstrated all stages in the development of the aneurysm. Follow-up angiography demonstrated an incidental dissecting aneurysm of the right vertebral artery. This aneurysm was also treated by endovascular embolization. No new neurological deficit appeared during or after the treatment. Multiple dissecting aneurysms are rare, especially those involving both supra- and infratentorial regions. A ruptured dissecting aneurysm of the ACA is also an uncommon vascular disorder. This case shows that rebleeding may occur, even during the chronic stage, and thus appropriate treatment for the prevention of subsequent bleeding is essential. Incidental dissecting aneurysms can be treated using the endovascular technique, but further study is necessary.     

Spontaneous dissection of the anterior cerebral artery presenting subarachnoid hemorrhage and cerebral infarction: a case report

A case is reported of anterior cerebral artery dissecting aneurysm presenting with subarachnoid hemorrhage and cerebral infarction. A 50-year-old man presented with sudden onset of weakness of the left lower limb was admitted to our hospital. CT scan on admission showed a subarachnoid hemorrhage in the interhemispheric fissure and CT on the 6th day demonstrated a cerebral infarction on the right medial frontal lobe. A carotid angiogram 12 hours after the onset showed no aneurysmal lesion, but, the angiogram repeated 11 days after the onset revealed an aneurysmal dilatation with distal narrowing at the right A2-A3 segment. To prevent rebleeding, we performed a wrapping procedure through the interhemispheric route on the 18th day after onset. The postoperative course was uneventful. We reviewed 27 previously reported cases with symptomatic dissecting aneurysm confined to the anterior cerebral artery.     

Ruptured dissecting aneurysms of the A1 segment of the anterior cerebral artery: three case reports and a review of the literature

Dissecting aneurysms in the anterior cerebral artery (ACA), although rare, can cause ischemic and/or hemorrhagic stroke. Hemorrhagic dissecting aneurysms in the A1 portion of the ACA are often associated with a poor prognosis. We retrospectively investigated three rare cases of hemorrhagic dissecting aneurysms in the A1 portion. Dissecting aneurysms were diagnosed by carotid angiography or computed tomography angiography to visualize morphological changes in the vessel. All patients presented with diffuse subarachnoid hemorrhage. In one case, computed tomography angiography performed at the onset of the subarachnoid hemorrhage revealed fusiform dilatation at the right ACA (A1), which did not appear on a magnetic resonance angiogram obtained 1 year prior to the onset of the subarachnoid hemorrhage. In the other two cases, A1 dissecting aneurysms were diagnosed from a growing aneurysmal bulge revealed at a non-bifurcated site via repeated carotid angiography. Two patients underwent surgical intervention (trapping or clipping), and their outcome was favorable, whereas the third patient died of delayed rebleeding before receiving surgical treatment. Hemorrhagic dissecting aneurysms in the A1 portion cause severe subarachnoid hemorrhage. Surgical treatments that include revascularization are necessary to prevent rebleeding, and direct surgery is recommended, particularly at the A1 portion.