Detection of cerebral artery fenestrations by computed tomography angiography

Background and purposeCerebral artery fenestrations (CAF) are rare congenital variations usually diagnosed by digital subtraction angiography (DSA). The aim of this study was to examine the frequency of occurrence of fenestrations in cerebral arteries and their coexistence with cerebral aneurysms in computed tomography angiography (CTA).Material and methodsAll reports of cerebral CTA (1140) performed in one institution from March 2005 to December 2007 were analysed. We found 40 patients with single fenestrations of the intracranial arteries. All 40 examinations were retrospectively reviewed for location of vascular malformations and presence of aneurysms or subarachnoid haemorrhage (SAH). Medical histories of those patients were then analysed for evidence of SAH and referral reasons for CTA.ResultsForty fenestrated arteries were found in CTA: 18 basilar arteries (45%), 16 anterior cerebral arteries (40%), 4 anterior communicating arteries (10%) and one middle cerebral artery (2.5%). Only one vertebral artery fenestration was found due to the technique of the examination. Six patients (15%) with fenestrated arteries had a total of 8 aneurysms, although only one aneurysm was ipsilateral to the fenestration. In 8 cases of SAH, two were with no evidence of vascular malformation. The coexistence of CAF and aneurysms in CTA amounted to 15% (6/40), but the incidence of ipsilateral aneurysm was only 2.5% (1/40) and it affected the anterior cerebral artery.ConclusionsBasilar artery fenestration is the most frequent observed fenestration in CTA, followed by anterior cerebral artery and anterior communicating artery fenestrations. Coexistence of fenestration and aneurysm is uncommon in CTA examination.     

Contralateral Transradial Access for Coil Embolization of Distal Anterior Cerebral Artery Aneurysm Associated With a Steep Ipsilateral A1-A2 Angle

ObjectiveEndovascular treatment of distal anterior cerebral artery aneurysms is commonly addressed via the ipsilateral A1 segment of the anterior cerebral artery. However, when the parent pericallosal artery has a sharp ipsilateral A1-A2 angle, catheterization through the ipsilateral A1 segment can potentially result in vessel injury, catheter kinking, and/or compromised/stagnant anterior cerebral artery flow. Here, we present a case of a distal anterior cerebral artery aneurysm associated with a steep ipsilateral A1-A2 angle treated with contralateral transradial coil embolization.Case presentationA 91-year-old woman presented with a ruptured left distal anterior cerebral artery aneurysm at the A3 segment. The parent pericallosal artery had a steep ipsilateral A1-A2 angle. To safely achieve coil embolization of the aneurysm, a contralateral transradial system via the right A1 segment was employed. Although a secondary ipsilateral transradial system was required for contrast injection, aneurysm obliteration was successfully achieved without vessel injury or system instability.ConclusionThe A1-A2 angle can be a key anatomical factor in the endovascular treatment of distal anterior cerebral artery aneurysms. The contralateral transradial system is a useful treatment option for distal anterior cerebral artery aneurysms associated with sharp ipsilateral A1-A2 angles. However, if the distal anterior cerebral artery aneurysm cannot be clearly visualized through the contralateral system, an ipsilateral system will be required for contrast injection.     

Superficial Temporal Artery to Anterior Cerebral Artery Hemi-bonnet Bypass Using Radial Artery Graft for Prevention of Complications after Surgical Treatment of Partially Thrombosed Large/Giant Anterior Cerebral Artery Aneurysm

Background

Partially thrombosed large/giant aneurysm of the anterior cerebral artery is still challenging because this complex aneurysm requires arterial revascularization in the deep operation field. Therefore, direct neck clipping is often impossible. We describe our experiences with extracranial-intracranial bypass as an insurance bypass prior to clipping of partially thrombosed anterior cerebral artery aneurysms, and discuss the microsurgical technique and strategy.

Traumatic aneurysm of the peripheral cerebral artery]

Two cases of traumatic aneurysm of peripheral cerebral artery were reported. Case 1. A 6-year-old girl was severely injured on her head by automobile accident. Plain skull films showed depressed fracture in the left frontal region. Left common carotid angiogram 25 days after the injury revealed small aneurysm of a cortical branch of the anterior cerebral artery. Cranioplasty and removal of the aneurysm was performed. Postoperative course of this patient was uneventful. Case 2. A 4-year-old girl fell downstaris and struck her left temporal region. On admission, she was unconscious and plain skull films showed multiple linear fractures. No aneurysm was demonstrated in the right common carotid angiogram immediately after the head trauma. Since her general condition gradually improved, she discharged 23 days after the head trauma. 63 days after the injury, she developed sudden onset of severe headache, vomiting, and status epilepticus. Right common carotid angiogram showed a large aneurysm arising from a branch of right pericallosal artery at the free edge of the falx. Parent artery of the aneurysm was clipped. Postoperatively, the patient made uneventful recovery. 60 reported cases of traumatic aneurysm of peripheral cerebral artery were reviewed and analyzed in etiology, diagnosis, clinical course, treatment and pathogenesis.     

A case of agenesis of the corpus callosum accompanied by a ruptured azygos anterior cerebral artery aneurysm and lipoma--a case report

A 53-year-old woman suffered from sudden onset of severe headache on February 28 in 1982. She was admitted to our hospital soon after onset. On admission, she had a severe headache and nausea, and her consciousness was drowsy. CT scan showed a marked subarachnoid hemorrhage with intracerebral and intraventricular hematoma, a separation of the lateral ventricles with enlargement of posterior horns, and deformity of anterior horn. By these findings, the patient was diagnosed as an agenesis of the corpus callosum with subarachnoid hemorrhage. Left carotid arteriogram revealed an azygos anterior cerebral artery and an aneurysm at the terminal portion of this artery. Surgery was performed on the 24 th day after subarachnoid hemorrhage. Operative finding revealed a little finger's head-sized tumor was situated over the right frontobasal artery. An azygos anterior cerebral artery aneurysm was clipped and tumor was removed. Pathological diagnosis of the tumor was a lipoma. Namely, she had an agenesis of the corpus callosum, an azygos anterior cerebral artery, an aneurysm and a lipoma. There are some reports in which an agenesis of the corpus callosum is accompanied with a lipoma and an azygos anterior cerebral artery is accompanied with an aneurysm. But a case of agenesis of the corpus callosum with an azygos anterior cerebral artery was rarely reported. So this rare case with these anomalies was reported and pathogenesis about the development of 4 anomalies was also discussed.     

Saccular bilobed aneurysm of an azygos anterior cerebral artery.

An azygos anterior cerebral artery is an anatomical variant in which the anterior communicating artery is absent and both the A1 segments unite to form a single A2 segment of the artery. This anatomical variant may be associated with holoprosencephaly and may predispose to aneurysm formation, however the association of such an anomaly with an aneurysm is rare. When associated with an aneurysm, it poses management difficulties due to the single distal anterior cerebral artery. Most of the reported aneurysms with such an anomaly are saccular and located in the distal part of the artery. We report a patient with a wide neck saccular multilobed aneurysm who presented after a grade 3 subarachnoid haemorrhage. A right pterional craniotomy and clipping of the aneurysm was performed following cerebral angiography. The mechanism of formation and difficulties in management of such an aneurysm is discussed.     

Absent anterior communicating artery and varied distribution of anterior cerebral artery

During the cerebral dissection of a 67-year-old male cadaver, a unique combination of variations at the circle of Willis and anterior cerebral artery (ACA) distribution were encountered. The A1 segment of both ACA were fused without an anterior communicating artery (ACoA), forming an X shape and giving rise to a common pericallosal artery (CPA), an incomplete distal ACA, and an incomplete distal anterior cerebral artery (IACA). The IACA had an unusual course, which may be important from the surgical point of view. The CPA continued as the A2 and A3 segments, and bifurcated into 2 pericallosal arteries. Branching patterns of the varied arteries to the interhemispheric region were evaluated, and results were discussed. Additionally, both posterior communicating arteries were hypoplastic. There was no aneurysm formation at the circle of Willis and its branches.     

3.0T磁共振MRA在蛛网膜下腔出血颅内动脉瘤筛查中的应用价值

目的探讨3.0T磁共振MRA在蛛网膜下腔出血颅内动脉瘤筛查中的应用价值。方法利用3.0T磁共振对31例因蛛网膜下腔出血而筛查出脑动脉瘤患者进行回顾性分析,31例脑动脉瘤患者均行常规T1WI、T2WI及3D TOF MRA检查,对检查的信息进行MIP、MPR及VR后处理并结合原始薄层图像进行分析诊断。所有病例均由DSA最后确诊后治疗。结果小动脉瘤(<5 mm)11个,中动脉瘤(>5 mm)13个,大动脉瘤(>10 mm)9个。动脉瘤的分布:大脑中动脉瘤8个,大脑前动脉瘤7个,大脑后动脉瘤3个,前交通动脉瘤5个,后交通动脉瘤6个,基底动脉瘤1个,颈内动脉海绵窦段动脉瘤2个,椎动脉瘤1个。结论 3.0T磁共振MRA可成为蛛网膜下腔出血颅内动脉瘤筛查的有效检查方法,值得临床推广。     

翼点微骨孔入路治疗颅内前循环动脉瘤

目的探讨应用微骨孔入路治疗颅内前循环动脉瘤的临床效果。方法2000年11月～2001年12月采用翼点微骨孔入路治疗前循环动脉瘤病人83例,共86个动脉瘤。其中颈内动脉眼段动脉瘤3例,颈内动脉C2段动脉瘤40例,颈内动脉分叉部动脉瘤4例,前交通动脉瘤19例,前动脉水平段动脉瘤2例,中动脉水平段5例,中动脉分叉部动脉瘤13例。结果成功治疗前循环动脉瘤病人83例,共夹闭86个动脉瘤。术后出现肢体活动障碍4例,占4.8%;无手术死亡。术后80例复查脑血管造影,显示动脉瘤消失。无与开颅入路相关的并发症。本组均未输异体血液,术中采用自体血回收后输血26例。结论翼点微骨孔入路夹闭颅内前循环动脉瘤,可以降低手术中的医源性损伤并获得满意的手术效果。     

A rare anatomical variant: median anterior cerebral artery fenestration associated with an azygous infra-optic anterior cerebral artery

We present a patient who had a median anterior cerebral artery fenestration with a congenital azygous infra-optic anterior cerebral artery. This rare combination of abnormalities was an incidental finding in a patient who suffered spontaneous subarachnoid haemorrhage from a ruptured anterior cerebral artery aneurysm.     

Microanatomy of the perforators of the anterior communicating artery complex

We describe the microanatomy of the perforating arteries arising from the anterior communicating artery complex (5 mm distal of the anterior cerebral artery, the anterior communicating artery, and 5 mm proximal of the distal anterior cerebral artery). Thirteen unfixed human brains were used in this study. The origin and number of perforators are described, as is the site of brain penetration, and results are correlated with previous studies. The hemodynamics of blood flow ib relation to the formation of an anterior communicating artery aneurysm and different surgical approaches are mentioned. The neuropsychological outcome after aneurysm clipping with regards to the pattern of blood supply from the anterior cerebral artery complex is also discussed. [Neural Res 1997; 19: 577-587]     

Early operation of ruptured basilar artery aneurysm associated with bilateral carotid occlusion (moyamoya disease)

A 34-year-old Caucasian man presented with subarachnoid hemorrhage. Angiography revealed bilateral carotid occlusion at the cavernous sinus and an aneurysm at the basilar artery bifurcation. The whole brain was supplied with blood from the basilar artery and posterior cerebral arteries through a large number of collateral vessels to the internal carotid artery bifurcation, middle cerebral and anterior cerebral arteries: the moyamoya phenomenon. The aneurysm was clipped within hours of the subarachnoid hemorrhage. The relation between moyamoya disease and basilar artery aneurysms is discussed and some surgical and management considerations are given.     

Wall shear stress in intracranial aneurysms and adjacent arteries

Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.     

Possible participation of clip rotation in the formation of de novo aneurysm.

During long term follow-up after successful treatment of ruptured intracranial aneurysms, a few patients develop newly formed (de novo) aneurysms, which account for 0.9-1.1% of all cerebral aneurysms. As for the etiology of de novo cerebral saccular aneurysms, hemodynamic stress is considered to be the most important factor. The woman whose case we present here had developed a ruptured anterior communicating aneurysm at the age of 52, and the aneurysm with its anterior projection was completely clipped. Eight years later, she suffered intraventricular hemorrhage. Angiogram showed a newly formed anterior communicating artery aneurysm, which projected to the side opposite the clip. Surgical exploration found the head of the clip had rotated and become trapped between optic nerves. We speculated the rotation of the clip used for the aneurysm at the first operation was one of the possible mechanisms, which caused a change in the direction of hemodynamics to the anterior communicating artery, leading to the development of de novo aneurysm. Every neurosurgeon should pay attention to the clip position until dural closure has been completed.     

Infraoptic Course of Both Anterior Cerebral Arteries

A 28-year-old woman was referred to our hospital with a sudden, very severe headache. Brain computed tomographic angiography showed a saccular cerebral aneurysm at the bifurcation of the left middle cerebral artery and infraoptic courses of both anterior cerebral arteries. The anterior cerebral arteries were seen to arise from the ipsilateral internal cerebral arteries at the level of the origin of the ophthalmic artery, passed underneath the ipsilateral optic nerve, and turned upward at ventral portion of the optic chiasm.Infraoptic course of the proximal anterior cerebral artery is an extremely rare anomaly and is often associated with cerebral aneurysms. We report the clinical features, radiological findings, and possible genesis of this anomaly with a literature review.     

前循环破裂动脉瘤伴颅内血肿的诊断与显微手术治疗(附21例分析)

目的探讨前循环动脉瘤破裂伴颅内血肿的诊断方法和显微手术治疗要点。方法回顾性分析21例前循环动脉瘤破裂合并颅内血肿病人的临床资料,其中前交通动脉瘤6例,后交通动脉瘤4例,眼动脉瘤1例,大脑中动脉瘤10例。均经3D-CTA检查确诊并急诊行显微外科手术治疗。结果夹闭术后随访3～18个月,死亡1例,重残1例,中残2例,其余17例病人恢复良好。结论对前循环破裂动脉瘤并颅内血肿病人应及早确诊并积极采取显微手术治疗。     

颅内破裂动脉瘤合并脑内血肿的复合手术治疗

目的 探讨复合手术治疗颅内破裂动脉瘤合并脑内血肿的疗效。方法 回顾性分析簧圈栓塞术后行颅骨钻孔血肿腔引流术治疗的5例颅内破裂动脉瘤合并脑内血肿的临床资料。结果 5例头颅CT均表现为典型蛛网膜下腔出血（SAH）合并脑内血肿;DSA发现动脉瘤位于大脑前动脉A2段分叉部1例、大脑前动脉A2段1例、前交通动脉1例、颈内动脉后交通动脉1例、大脑中动脉分叉部1例;术前Hunt-Hess分级Ⅱ级2例,Ⅲ级2例,Ⅳ级1例。引流术后3~4 d血肿大部分引流干净,无再出血、感染及脑梗死。术后6个月GOS评分3分1例,4分1例,5分3例。结论 对合并脑内血肿的自发性SAH,首先应考虑动脉瘤破裂出血可能,需尽早行DSA检查明确诊断;复合手术对于部分未发生脑疝又合并脑内血肿的破裂动脉瘤是可行的,能取得良好的疗效。     

270例动脉瘤性蛛网膜下腔出血积血部位与动脉瘤部位相关性分析

目的研究动脉瘤性蛛网膜下腔出血的积血部位与动脉瘤部位之间的相关性。方法回顾性分析270例动脉瘤性蛛网膜下腔出血患者的影像学资料,以了解积血部位与动脉瘤部位之间的相关性。结果 270例患者中前交通动脉瘤86例,大脑前动脉瘤19例,头颅CT均显示前纵裂积血;脉络膜前动脉瘤40例,后交通动脉瘤82例,多数在CT上显示广泛鞍上池积血,病变同侧积血多于对侧;大脑中动脉瘤32例,CT多显示病变同侧外侧裂积血;后循环动脉瘤11例,头颅CT多见鞍上池及脑室系统积血;出血量较大时,除具备上述特征外,积血部位更广泛,特异性相对较小。结论动脉瘤性蛛网膜下腔出血的积血部位与动脉瘤部位存在一定的对应关系,根据头颅CT所示积血部位可初步判断动脉瘤的部位,对数字减影血管造影时血管检查顺序的选择及治疗方法的预估有重要价值。     

Intraaneurysmal embolization of an unruptured basilar tip aneurysm associated with moyamoya disease.

We describe a patient with moyamoya disease associated with an unruptured basilar tip aneurysm which was treated by endovascular embolization using Guglielmi detachable coils (GDCs). A 53-year-old man presented with left hemiparesis persisting for 3 mon ths before admission. Cerebral angiography revealed occlusion of the bilateral middle cerebral arteries and the left anterior cerebral artery, stenosis of the right anterior cerebral artery, and basal moyamoya vessels. In addition, a saccular small aneurysm was seen at the top of the basilar artery. The aneurysm was completely embolized by intraaneurysmal GDCs. Direct surgical clipping is often selected for the treatment of posterior fossa aneurysms in moyamoya disease. However, complete clipping is usually difficult due to the difficulties in operative technique associated with moyamoya disease. We suggest that the endovascular treatment using GDCs is comparatively safe and effective for the treatment of surgically difficult aneurysms in patients with moyamoya disease.     

Involvement of internal elastic lamina in development of induced cerebral aneurysms in rats

To elucidate the role of the internal elastic lamina in the development of cerebral aneurysm, the bifurcation of the anterior cerebral artery and olfactory artery was histologically studied in control and experimental rats treated with unilateral carotid ligation and renal hypertension. Various stages of aneurysm formation were compared, and it was found that early aneurysmal changes were always present just distal to the apical intimal pad on the anterior cerebral artery side. The internal elastic lamina was thinned and fragmented just distal to the pad even in the very early stage of aneurysm formation when the medial layer was still present. In control rats, the internal elastic lamina had a tendency to thin and fragment at the site where aneurysms would develop in experimental rats. Our study shows that changes of the internal elastic lamina were present just distal to the pad even in control rats, which never develop cerebral aneurysms. Under hemodynamic stress augmented by experimental treatments, further degenerative changes of the internal elastic lamina and involvement of the medial layer are considered to occur and result in aneurysm formation there.