Benign arterial dissections of the posterior circulation

Spectrum of Posterior Cerebral Artery Dissection: A Retrospective Observational Study and a Critical Review

Background and Aims

Intracranial arterial dissections commonly involve the vertebrobasilar system leading to subarachnoid hemorrhage (SAH) or cerebral infarction attributable to a dissecting aneurysm of the vessel or occlusion of the lumen depending on the depth of dissection. However, isolated posterior cerebral artery dissections (PCADs) are rare and sparsely reported in the literature.

Methodology

A retrospective multicentric observational study was carried out after collecting data from 14 patients admitted with PCAD in three hospitals of Kolkata, Jaipur, and Patna within the period of July 2021 to June 2022.

Results

The median age of the population was 48.5 years, and 64.28% were females. SAH was the most common presentation with dissecting aneurysms in all patients barring one, who presented with a left occipital infarct consequent to ipsilateral PCAD. Among the 14 patients, three patients denied endovascular intervention and were lost to follow-up; one patient with an occipital infarct and another patient with a dissecting left P3 aneurysm, which underwent spontaneous thrombosis, were managed conservatively. Among the nine patients scheduled for endovascular coiling, one patient succumbed before intervention and one patient succumbed to sepsis in the postoperative period. A complete recovery was noted in six patients, whereas residual neurodeficits were present in three patients. Among the six patients who had an uneventful recovery at the end of 3 months, five patients had an endovascular intervention.

Conclusion

PCAD may present with large-scale neurodeficits and is associated with high morbidity and mortality, hence necessitating prompt management. Conservative management is preferable for consequent infarcts, whereas endovascular management is desirable in cases of dissecting aneurysms, which usually tend to have a favorable outcome if intervened early.

Microsurgical Treatment Strategy of Vertebral Artery Fusiform Aneurysm-From the Standpoint of Hemodynamic Integrity and Perforator Preservation

During treatment of vertebral artery (VA) fusiform aneurysms, it is critical to preserve peripheral perforators and anterograde blood flow of the VA and to reduce hemodynamic load to the contralateral VA. Even in the era of endovascular treatment, there are still many benefits to using microsurgical treatments with appropriate clip application and preservation of the perforators around the aneurysm, in conjunction with various bypass techniques. The ideal microsurgical technique involves reconstructive clipping that obliterates the aneurysm but preserves anterograde blood flow of the VA, followed by isolation of the aneurysm and VA reconstruction. If these two methods are unavailable, proximal clipping of the aneurysm combined with flow-augmentation bypass to the distal branch can be considered as an alternative surgical management. We discuss the microsurgical treatment of unruptured VA fusiform aneurysms in our surgical cases on the basis of a review of the current literature.

Radical treatment of ruptured dissecting aneurysm on the P1 segment with monotherapy using multiple LVIS stents

The standard endovascular treatment for ruptured dissecting aneurysm is a parent artery occlusion. However, this treatment is unsuitable when the artery of the lesion gives off perforating vessels that supply blood to critical regions or when the collateral flow cannot be expected due to the sacrifice of the parent artery. Here, we present an infrequent case of ruptured dissecting aneurysm on P1 segment of the posterior cerebral artery. The aneurysm had little sac for coiling and the artery of the lesion had some perforator branches; thus, we selected the monotherapy with three overlapping low-profile visualised intraluminal support stents as radical treatment, which resulted in prompt obliteration of the aneurysm. The patient was fully recovered at 3 months after the procedure. Previous studies have reported the effectiveness of multiple stents alone for dissecting aneurysms, whereas this case showed that overlapping stents may also be effective on the P1 segment.

Optional Endovascular Therapy of Dissecting Posterior Cerebral Artery Aneurysm

BACKGROUND

Posterior cerebral artery aneurysms are uncommon, with an occurrence rate of less than 1% of intracranial aneurysms. They have various shapes, including saccular and fusiform. Dissecting aneurysms may occur in distal posterior cerebral artery and they may affect the whole artery. Endovascular therapy is considered as a safe method of treatment and there are different techniques for endovascular therapy.

SUMMARY

Posterior cerebral artery aneurysms are uncommon. Endovascular therapy is considered as a safe method of treatment and there are different techniques for endovascular therapy. We present here three cases collected from Maison Blanche Hospital (Intervention Neuroradiology Department, CHU Reims, France) during 2011-2012; they were females, at a young age and the affected side was on the right. The first case was affected at the P2-P3 segment, the aneurysm was fusiform in shape and she presented with ischemic stroke, while the second and third cases were affected at the P2 segment, the aneurysms being saccular in shape; one of them presented with subarachnoid hemorrhage with a history of migraine and the other patient presented with ischemic stroke. All of them had no history of trauma, hypertension or other diseases. One patient was treated by coiling and sacrificing the parent artery, the second patient was treated with stent-assisted coils, and the third one was treated by coiling without sacrificing the parent artery.

Dissecting intracranial aneurysm in pregnancy: A rare association

We report a case of dissecting aneurysm of the right posterior cerebral artery presenting with sudden onset headache and altered behavior during labor. A 26-year-old P1001 with uncomplicated antenatal period, except history of headache off and on since 32 weeks of pregnancy, developed sudden onset headache and altered behavior during 3^rd stage of labor. She had vaginal delivery and a live born male baby was delivered with good Apgar score. The CT was suggestive of subarachnoid hemorrhage and DSA was suggestive of dissecting aneurysm of the right P2 segment with hypoplasia of right P1 segment and A1 segment of posterior and anterior cerebral artery, respectively. The patient was managed conservatively. At 4-month follow-up, the patient was doing well. We discuss about the rare association of a dissecting aneurysm and pregnancy, especially dissection of the posterior cerebral artery.

Endovascular Treatment of Spontaneous Intracranial Fusiform and Dissecting Aneurysms: Outcomes Related to Imaging Classification of 309 Cases

OBJECTIVE

To propose a modified classification system for spontaneous intracranial dissecting aneurysms (IDAs) that can guide treatment decisions.

METHODS

Between January 2010 and December 2015, 3183 consecutive patients were referred to our department for endovascular treatment of a cerebral aneurysm. Among this group, 309 patients harboring a total of 323 spontaneous IDAs were identified. Based on a modified imaging classification system, spontaneous IDAs were classified into 4 subtypes: classic dissecting aneurysm, segmental ectasia, dolichoectatic dissecting aneurysm, and large mural bleeding ectasia. A logistic regression analysis was conducted to identify predictors of clinical outcomes.

RESULTS

Of the 323 IDAs, 216 (66.87%) were treated with stent-assisted coiling, 47 (14.55%) with internal trapping, and 60 (18.58%) with sole stenting. Of the 309 patients, 8 (2.59%) suffered intraoperative complications, 40 (12.94%) experienced postoperative complications, 9 died (2.79%), and 1 (0.32%) had severe disability. The mean duration of clinical follow-up of the 309 patients was 10.40 months (range, 3-72 months). Imaging follow-up was available for 262 patients (274 IDAs), with a mean duration of 7.10 months (range, 3-60 months), and 24 aneurysm recurrences (9.16%) were noted. Aneurysm type was the sole independent predictor of different outcomes on logistic regression analysis (P = 0.004).

CONCLUSIONS

There was a strong relationship between the subtypes of spontaneous IDAs and clinical course. Our classification system is confirmed to be helpful in assessing patients' prognosis and guiding their treatment.

Spontaneous Resolution of a Ruptured Dissecting PICA Aneurysm

Spontaneous dissecting aneurysms (SDAs) seldom involve the intradural vertebral artery VA, the posterior cerebral, basilar or postero inferior cerebellar arteries (PICAs), where they produce subarachnoid haemorrhage and/or ischaemia.

These lesions may develop spontaneously or occasionally after minor trauma and occur in young people in whom there is no underlying abnormality to explain the appearance of the dissection in most cases.

Spontaneous dissecting aneurysm of the PICA is rare and its natural history is not well understood. Surgery or endovascular treatment for PICA dissection remain controversial because they suggest vessel occlusion. Only in a few cases is the bypass between the occipital artery and the PICA possible with trapping of the dissected segment. Reinforcement of the arterial wall does not seem efficient and the surgical approach per se with sole exclusion of the aneurysm may be disastrous.

We describe two cases of SDA of PICA that presented with subarachnoid haemorrhage (SAH), treated conservatively, with spontaneous cure of the lesions, angiographically confirmed at mid-time follow-up of five and four months. These favourable spontaneous thromboses, like 11 other similar case reported in the literature, did not show any rebleed. The possibility of a benign clinical course of this lesion exists; clinical and angiographic management of the patient before a decision for a aggressive treatment is proposed.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

Basilar extension and posterior inferior cerebellar artery involvement as risk factors for progression of the unruptured spontaneous intradural vertebral artery dissection

BACKGROUND AND PURPOSE

Spontaneous intradural vertebral artery dissection (siVAD) primarily causes stroke in young and middle-aged individuals; however, data on the relationship between vertebrobasilar morphology and the progression of siVAD are limited.

METHODS

We retrospectively reviewed the data of 77 adult patients who were diagnosed with unruptured siVAD and treated conservatively. We analysed the clinical characteristics, vertebrobasilar morphologies and progression. Progression was defined as siVAD-induced stroke or morphological worsening of the siVAD.

RESULTS

Twenty patients experienced progression. Recurrent ischaemic events that occurred in the vertebrobasilar territory were seen in three patients (3.9%). Two of these three patients and other 17 patients showed morphological worsening. None of the patients presented with subarachnoid haemorrhage. The log-rank test showed male sex, migraine, basilar extension and the posterior inferior cerebellar artery involvement were associated with the progression. Multivariate analysis using the Cox proportional hazards model showed that only basilar extension and the posterior inferior cerebellar artery involvement were significantly related to the progression (p=0.012 and 0.019). In addition, patients with these two vertebrobasilar morphologies had a significantly shorter period of progression of siVAD than those without these morphologies (both, median 242 days; one of two, median 1292 days; none, median 2445 days).

CONCLUSIONS

Thus, some vertebrobasilar morphologies might be markers of the progression of unruptured siVAD. Although all unruptured siVAD patients should be closely monitored, those with basilar extension and posterior inferior cerebellar artery involvement should perhaps be more carefully followed than those without such morphologies.

Natural course of dissecting vertebrobasilar artery aneurysms without stroke

BACKGROUND AND PURPOSE

The natural history and therapeutic management of dissecting vertebrobasilar aneurysms without ischemic or hemorrhagic stroke (nonstroke dissecting vertebrobasilar aneurysms) are not well-established. We conservatively followed patients with nonstroke dissecting vertebrobasilar aneurysms and evaluated the factors related to clinical and morphologic deterioration.

MATERIALS AND METHODS

One hundred thirteen patients were enrolled and divided by clinical presentation at diagnosis: asymptomatic (group 1, n = 52), pain only (group 2, n = 56), and mass effect (group 3, n = 5). Patients were conservatively managed without intervention and antithrombotic therapy. Clinical outcomes and morphologic changes were analyzed.

RESULTS

A total of 113 patients who were diagnosed with nonstroke dissecting vertebrobasilar aneurysm had a mean follow-up of 2.9 years (range, 27 days to 8 years). Throughout that period, 1 patient in group 1 (1.9%) and 1 patient in group 2 (1.8%) showed clinical deterioration due to mass effect, and 1 patient in group 3 (20%) developed ischemic stroke followed by subarachnoid hemorrhage. Most patients (97.3%) were clinically unchanged. Three patients who had clinical deterioration showed aneurysm enlargement (P < .001). Aneurysms remained morphologically unchanged in 91 patients (80.5%). Aneurysm enlargement was seen in 5 patients (4.4%); risk of enlargement was significantly associated with either maximum diameter (hazard ratio = 1.30; 95% CI, 1.11-11.52; P = .001) or aneurysm ≥10 mm (hazard ratio = 18.0; 95% CI, 1.95-167; P = .011).

CONCLUSIONS

The natural course of these lesions suggests that acute intervention is not always required and close follow-up without antithrombotic therapy is reasonable. Patients with symptoms due to mass effect or aneurysms of >10 mm may require treatment.

Long-term follow up of antegrade recanalization of vertebral artery dissecting aneurysm after internal trapping: case report

A 34-year-old female presented with subarachnoid hemorrhage caused by the rupture of a right vertebral artery (VA) dissecting aneurysm. The affected site, including the aneurysm and parent artery, was successfully occluded with detachable coils. Follow-up angiography performed 28 days after the endovascular treatment revealed recanalization of the parent artery. We decided to treat the patient conservatively without further intervention because the aneurysm had been completely occluded. Magnetic resonance imaging showed a normal VA configuration with a minor irregularity of the affected wall at 6 years after onset. Rebleeding tends to occur during the acute stage because spontaneous healing of the dissecting vascular wall typically occurs within one month after onset. Our case suggests that additional intervention is unnecessary during the chronic stage once the aneurysm has been occluded and no further signs of the development of VA dissection are found.

Endovascular treatment of intracranial artery dissection: clinical and angiographic follow-up

Background. Intracranial artery dissections are rare and many controversies exist about treatment options. The aim of this study was to evaluate the efficacy and safety of the endovascular approach in patients with an intracranial dissection presenting with different symptoms. Methods. We prospectively evaluated the clinical features and treatment outcomes of 30 patients who had angiographically confirmed nontraumatic intracranial dissections over 4 years. Patients were followed up for 17 months, and their final outcomes were assessed by the modified Rankin Score (mRS) and angiography. Results. Sixteen (53.3%) patients had a dissection of the anterior circulation, whereas 14 (46.7%) had a posterior circulation dissection. Overall, 83.3% of the patients suffered a subarachnoid hemorrhage (SAH). Grade IV Hunt and Hess score was seen in 32% of the SAH presenting cases. Parent artery occlusion (PAO) with coil embolization was used in 70% of the cases. The prevalence of overall procedural complications was 23.3%, and all were completely resolved at the end of follow-up. No evidence of in-stent occlusion/stenosis or rebleeding was observed in our cases during follow-up. Angiography results improved more frequently in the PAO with coil embolization group (100%) than in the stent-only-treated group (88.9%) (P = 0.310) and the unruptured dissection group (5/5, 100%) in comparison with the group that presented with SAH (95.8%) (P = 0.833). Conclusion. Favorable outcomes were achieved following an endovascular approach for symptomatic ruptured or unruptured dissecting aneurysms. However, the long-term efficacy and durability of these procedures remain to be determined in a larger series.

Traumatic dissecting posterior cerebral artery aneurysm. A case report and review of the literature

Dissecting posterior cerebral artery (PCA) aneurysms are among rare cerebrovascular malformations accounting for 2% to 6% of all aneurysms. Herein we describe a case of pediatric dissecting aneurysm located in the PCA with documentation of aneurysm development. In addition, we discuss its treatment with a new therapeutic method involving glue injection.

Recanalisation of spontaneously occluded vertebral artery dissection after subarachnoid haemorrhage

Spontaneous occlusion is a rare manifestation of ruptured vertebral artery dissection (VAD). Its natural history and treatment strategy have yet to be established due to its rarity. Here, we report five lesions involving spontaneous occlusion of VAD after subarachnoid haemorrhage, among which three lesions showed recanalisation. Based on our experience and previous reports, spontaneous occlusion of ruptured VAD can be classified into two groups-one group with occlusion in the acute stage with a high incidence of recanalisation and another group with occlusion in the chronic stage with a relatively low incidence of recanalisation. The underlying mechanism is likely different in each group, and treatment strategies should also be tailored depending on the pathophysiology.

Dissecting aneurysms of the vertebral artery--angiographic patterns at the dissecting site on balloon test occlusion

Introduction

At present, the risk of future hemorrhage or ischemic insult from vertebral artery (VA) dissection cannot be estimated from available imaging data. We investigated the relationship between symptoms and the angiographic patterns of the dissecting site on balloon test occlusion (BTO) to develop guidelines for clinical decision-making.

Methods

We retrospectively reviewed 18 patients with unilateral VA dissection who presented with subarachnoid hemorrhage (SAH) or cerebral infarction. We analyzed the angiographic findings at the dissecting site on contralateral VA angiograms during BTO of the affected VA, classified the angiographic patterns into two types, and compared the symptoms they presented.

Results

Patients with dissection opacified from the distal to the proximal side are more likely to present with cerebral infarction than SAH. Conversely, patients with dissection opacified from the proximal to the distal side had a significantly higher incidence of SAH.

Conclusions

Angiographic findings at the dissecting site on contralateral VA angiograms during BTO of the affected VA are helpful for considering the treatment and prognosis of patients with VA dissecting aneurysms.

Basi-parallel anatomical scanning magnetic resonance imaging in patients with bilateral vertebrobasilar artery dissections

A 31-year-old man presented with bilateral unruptured vertebral artery (VA) dissections. The temporal course of the dissected arteries was successively evaluated using brain surface imaging modality basi-parallel anatomical scanning (BPAS) magnetic resonance (MR) imaging in combination with the conventional modalities of MR angiography and three-dimensional computed tomography (3D-CT) angiography. Initially, BPAS-MR imaging clearly demonstrated bilateral fusiform dilatations of the arterial wall, whereas MR angiography and 3D-CT angiography showed irregular, dilated, or interrupted inner contour of the arteries. Finally, BPAS-MR imaging demonstrated resolution of both aneurysms, and MR angiography demonstrated obstruction of the left VA and normal contours of the right VA. Combination of diagnostic tools such as BPAS-MR imaging and MR angiography is useful for evaluating the exact nature of dissected arteries and determining the temporal course.

Comparison of clinical characteristics and MR angiography appearance in patients with spontaneous intradural vertebral artery dissection with or without subarachnoid hemorrhage

Object

It is well known that spontaneous intradural vertebral artery dissection (siVAD) is an important cause of nontraumatic subarachnoid hemorrhage (SAH). The factors that influence whether SAH develops, however, remain unclear. The aim of this study was to investigate whether clinical characteristics and imaging findings are different in patients with siVAD with SAH compared to those with siVAD without SAH.

Methods

The authors conducted a retrospective, single-institution study involving patients in whom siVAD developed with or without SAH, between July 2003 and November 2010. Univariate and multivariate analyses were performed to evaluate clinical characteristics and MR angiography findings. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between line of the basilar artery trunk and line of the vertebral angle (VA) at the vertebral union on 3D MR angiograms.

Results

Among 58 patients with siVAD, 21 developed SAH. The presence of siVAD and SAH was significantly associated with higher rates of current smoking (OR 13; 95% CI 3.6–38; p < 0.0001), dissection of the dominant VA (OR 9.2; 95% CI 2.5–19; p = 0.0004), and unruptured supratentorial nondissecting saccular aneurysms (OR 11; 95% CI 2.1–19; p = 0.0025), and the VUBA of the dominant VA was significantly larger (p < 0.0001, univariate analysis). Multivariate analysis showed that these differences were still significant (p < 0.05).

Conclusions

A larger VUBA of the dominant VA, the presence of unruptured supratentorial nondissecting saccular aneurysms, and current smoking may be factors that predict which patients with siVAD will develop SAH by dominant VAD.

Dissecting aneurysms of posterior cerebral artery: clinical presentation, angiographic findings, treatment, and outcome

BACKGROUND

The dissecting posterior cerebral artery (PCA) aneurysms are very rare. These aneurysms pose significant treatment challenge and need careful evaluation to formulate an optimal treatment plan in case of ruptured or un-ruptured presentations.

METHODS

Retrospective review of a prospectively collected data.

RESULTS

Seven patients with dissecting aneurysms of the PCA were identified. Six out of seven presented with subarachnoid hemorrhage (SAH) and one with ischemic stroke. Three out of seven were treated with endovascular coil embolization without sacrifice of the parent artery and the rest had parent artery occlusion (PAO) with coil embolization. None of the patients developed new neurological deficits post-procedure. Aneurysm re-occurred in two patients that were treated without PAO.

CONCLUSION

Endovascular treatment of the dissecting PCA aneurysm is safe and feasible. It can be performed with or without PAO. Recurrence is more common without PAO and close follow-up is warranted.

Strategy for Treating Unruptured Vertebral Artery Dissecting Aneurysms

BACKGROUND

The natural course of unruptured vertebral artery dissecting aneurysms (VADAs) remains unclear.

OBJECTIVE

The purpose of this retrospective study was to develop a strategy for treating unruptured VADAs based on long-term follow-up.

METHODS

Our study population consisted of 100 patients with unruptured VADAs; in 66, the initial symptom was headache only, 30 presented with ischemic symptoms and 4 with mass effect. All underwent magnetic resonance imaging and magnetic resonance angiography at the time of admission and 2 weeks and 1, 3, 6, 12, and 24 months after the onset. If the dissection site was demonstrated to be enlarged on magnetic resonance imaging and magnetic resonance angiography without the manifestation of new symptoms, the patients received additional treatment to prevent bleeding.

RESULTS

Of the 100 patients, 4 underwent early intervention because of symptom exacerbation. The other 96 were initially treated conservatively; during follow-up, 5 manifested lesion enlargement on magnetic resonance angiography. Nine patients received additional treatment; 1 underwent direct surgery with trapping of the dissection site, and 8 underwent coil embolization. The other 91 patients continued to be treated conservatively; the dissection site remained unchanged in 70, improved or healed in 18, and disappeared in 3 patients. We treated 38 patients with recurrent ischemic attacks with antiplatelet therapy. No patients experienced bleeding or permanent neurological deficits during follow-up.

CONCLUSION

The nature of an unruptured VADA is not highly aggressive. However, if the dissection site enlarges without the manifestation of new symptoms, it should be occluded. In patients with recurrent ischemic attacks antiplatelet therapy should be considered.

Intracranial arterial dissections in ischemic stroke assessed by 3D rotational angiography

BACKGROUND

Dissections involving intracranial arteries are sometimes difficult to assess using conventional digital subtraction angiography (DSA). We evaluated the value of three-dimensional rotational angiography (3D-RA) for the assessment of intracranial arterial dissections (ICADs).

METHODS

The subjects were 39 patients (26 males, 13 females; average age 50+/-15years) who were diagnosed as having ICADs and who underwent both DSA and 3D-RA in our hospital between April 1999 and March 2005. We retrospectively compared 3D-RA images to conventional DSA images in a blinded manner with respect to double lumen sign, pearl and string sign, string sign, and aneurysmal dilatation. On the basis of the caliber size of the artery affected by dissections, we divided patients into two groups: smaller artery group (S group) and larger artery group (L group).

RESULTS

The detection rate of double lumen sign with 3D-RA (79%) was significantly higher than with conventional DSA (18%; P<0.001). Reliable findings of arterial dissections (double lumen sign and/or pearl and string sign) were observed more often with 3D-RA (90%) than with conventional DSA (36%; P<0.001). In S group, the double lumen sign was detected only with 3D-RA.

CONCLUSIONS

3D-RA allows increased conspicuity of ICADs findings with conventional DSA, especially in smaller-caliber intracranial arteries.

Application of covered stent grafts for intracranial vertebral artery dissecting aneurysms

Object

Utilization of covered stent grafts in treating neurovascular disorders has been reported, but their efficacy and safety in vertebral artery (VA) dissecting aneurysms needs further investigation.

Methods

Six cases are presented involving VA dissecting aneurysms that were treated by positioning a covered stent graft. Two aneurysms were located distal to the posterior inferior cerebellar artery, and 4 were located proximal to the posterior inferior cerebellar artery. Aspirin as well as ticlopidine or clopidogrel were administered after the procedure to prevent stent-related thrombosis. All patients were followed up both angiographically and clinically.

Results

Five of the 6 patients underwent successful placement of a covered stent graft. The covered stent could not reach the level of the aneurysm in 1 patient with serious vasospasm who died secondary to severe subarachnoid hemorrhage that occurred 3 days later. Patient follow-up ranged from 6 to 14 months (mean 10.4 months), and demonstrated complete stabilization of the obliterated aneurysms, and no obvious intimal hyperplasia. No procedure-related complications such as stenosis or embolization occurred in the 5 patients with successful stent graft placement.

Conclusions

Although long-term follow-up studies using a greater number of patients is required for further validation of this technique, this preliminary assessment shows that covered stent graft placement is an efficient, safe, and microinvasive technique, and is a promising tool in treating intracranial VA dissecting aneurysms.

Management of posterior fossa dissecting aneurysms

SUMMARY

Treatment and prognosis of 14 patients of posterior fossa arterial dissections (AD) and dissecting aneurysms (DA) in one institution was reviewed. Internal trapping of aneurysm was performed for six patients presenting with SAH (three Vertebral, one posterior cerebral, one posterior inferior cerebellar, one anterior inferior cerebellar DA). The patency of the parent arteries was preserved in four DA patients with SAH (two Vertebral, two Basilar DA), 1 incidental vertebral DA, and one DA patient with brainstem infarction using stents and coils (four patients) or coils only (two patient). Proximal occlusion of parent artery was performed in a vertebral DA with SAH. One patient with a superior cerebellar DA presented with a midbrain infarct developed SAH with spontaneous occlusion of the aneurysm two weeks later. Of the 14 cases, ten were angiographically stable or cured during a follow up period of four to 70 months. one spontaneously resolved and two recurred. There was one death.

Conservative treatment of ruptured vertebrobasilar dissecting aneurysm

Ruptured vertebrobasilar dissecting aneurysm is usually treated surgically because rebleeding negatively affects outcome. However, the risk of rebleeding decreases markedly once several hours have passed from the initial bleeding. Moreover, surgery-related complications are not rare. We describe seven patients with ruptured vertebrobasilar dissecting aneurysm. To prevent rebleeding during the acute stage, we treated all seven patients conservatively with fentanyl instead of emergency surgery. During the follow-up period (mean 20 months), no patient suffered rebleeding. Conservative treatment with fentanyl administration may be a good option for management of ruptured vertebrobasilar dissecting aneurysm during the acute stage.

Dissecting aneurysms limited to the basilar artery: report of two cases and review of the literature

Spontaneous dissecting aneurysms limited to the basilar artery are rare. We describe two patients who presented to our institution with different clinical problems, one with brain stem infarction and the other with subarachnoid hemorrhage. We describe the clinical and imaging features in these patients, their treatment, and outcome. We also reviewed the literature concerning this entity, and we have identified 32 patients (including our two patients) with angiographically confirmed dissecting aneurysms limited to the basilar artery. Of these, 40.6% presented with brain stem infarction, 50.0% presented with subarachnoid hemorrhage, and 9.4% presented with both infarction and subarachnoid hemorrhage. Patients who presented with basilar artery dissecting aneurysms and brain stem infarction tended to be younger (mean age, 38 +/- 7 years) than those who presented with subarachnoid hemorrhage (48 +/- 12 years) and were more likely to be male. We discuss the natural history of this entity and suggest an approach to clinical management for these patients.

Postpartum dissecting aneurysm of the posterior cerebral artery

Intracranial dissecting aneurysm may cause subarachnoid hemorrhage (SAH) or infarction, and postpartum dissecting aneurysm is rare. A 30-year-old 6 days postpartum woman presented with posterior cerebral artery (PCA) dissection evolving dramatically over a short period. She had been well until 6 days after delivery when she suffered sudden onset of headache, vomiting, and unconsciousness. CT scan demonstrated SAH and digital subtraction angiography (DSA) revealed a fusiform dilatation of the left PCA (P3/P4 segment). The initial diagnosis was ruptured dissecting aneurysm, and conservative management was recommended in the acute period. DSA showed smoothening of the vascular wall 6 days after onset, and obliteration of the left P3/P4 segment was observed 13 days after onset. She was discharged without neurological deficits 26 days after onset. Postpartum SAH due to dissecting aneurysm of the PCA is rare, but should be considered in the differential diagnosis of postpartum headache.

3T MRI - 3D DSA Fusion Technique on Posterior Cerebral Artery Dissecting Aneurysm: Understanding a Potential Pathophysiologic Mechanism

SUMMARY

We aimed to show the anatomical relationship between a dissecting aneurysm of the posterior cerebral artery (PCA) and tentorial free edge to understand the pathophysiologic mechanism. A 52-year-old woman with a history of head trauma presented with dizziness and numbness in her left fingers. 3D DSA showed a dissecting aneurysm of the right P2-P3 segment of PCA. The fusion of 3D DSA and 3T MRI was performed at the dedicated workstation using three pairs of landmarks including the ICA termination, MCA bifurcation and A1-A2 junction of the right ACA. Fusion of 3D DSA and 3T MRI clearly demonstrated the dissected segment of PCA crossed the tentorial free edge twice. The fusion images support the direct trauma hypothesis of dissecting aneurysm of the P2-P3 segment of PCA. This novel imaging technique shows future potential to be used to understand the anatomical relationships between various vascular lesions and surrounding structures.

Prediction of rebleeding from angiographic features in vertebral artery dissecting aneurysms

To identify patient characteristics and angiographic features that predict high risk for rebleeding in vertebral artery (VA) dissecting aneurysms. We analyzed 62 patients treated for subarachnoid hemorrhage (SAH) from VA dissecting aneurysms (male: female, 46:16; mean age, 51.7 +/- 8 years). Univariate and multivariate stepwise logistic regression analyses were performed to assess relationships between rebleeding rate and age, gender, history of hypertension, sidedness of the aneurysm, angiographic configuration, and location relative to the origin of the posterior inferior cerebellar artery (PICA). Rebleeding occurred in 22 patients (37%), mostly within 24 h. Patients without rebleeding had favorable outcomes, while patients with rebleeding showed higher mortality. Angiographic patterns with high rebleeding rates included "stenosis and dilation" (50%), and "lateral protrusion" (43%), contrasting with "dilation and stenosis" (20%) and other types. Rebleeding also was likely in aneurysms proximal to or at the PICA origin (rate, 47% or 46%) than distal to the PICA origin (21%). Multivariate logistic regression analysis found two factors independently associated with rebleeding: angiographic pattern of the aneurysm (odds ratio 1.88:1, P=0.0366), and location relative to the PICA origin (odds ratio 4.93:1, P=0.028). High risk of rebleeding in VA dissecting aneurysms can be predicted by angiographic configurations such as "stenosis and dilation" and "lateral protrusion" and by location at or proximal to the PICA origin.

Paediatric dissecting posterior cerebral aneurysms: report of two cases and review of the literature

INTRODUCTION

Intracranial aneurysms in the paediatric population are uncommon, accounting for 2% to 6% of all aneurysms, and spontaneous arterial dissection is rarely reported as the cause of aneurysms in children, especially in the posterior cerebral artery.

METHODS

Two cases of paediatric spontaneous posterior cerebral artery dissecting aneurysms are reported, one in a 33-month-old male child presenting with aneurysmal rupture and subarachnoid haemorrhage and the other in a 9-year-old boy with an unruptured aneurysm.

RESULTS

The first child was successfully treated by endovascular parent vessel occlusion without neurological deficit and in the second a spontaneous thrombosis of the aneurysm and its parent artery occurred associated with hydrocephalus and a favourable outcome.

CONCLUSION

Dissecting aneurysms are dynamic lesions with variable and unpredictable evolution and close follow-up and/or early treatment is warranted. Spontaneous arterial dissection is a rare, probably still under-recognized, cause of intracranial aneurysms that may be responsible for a significant number of aneurysms and spontaneous aneurysmal thromboses in children.

Clinical analysis of vertebrobasilar dissection

BACKGROUND

The natural history of vertebrobasilar artery dissection (VAD) is not fully known. The purpose of this study was to review the clinical outcome of the patients with VAD, then to propose an appropriate management strategy for VAD.

METHOD

From 1992 to 2004, 35 VAD patients admitted to our institutes were retrospectively reviewed. There were 28 men and 7 women, whose age ranged from 4 to 67 years with a mean age of 44 years. Angiography was assessed to document the shape, and location of the dissecting aneurysm with respect to the posterior inferior cerebellar artery (PICA). A modified Rankin score was assigned for functional outcome. The functional outcome scores were analyzed according to the patient's age, gender, hypertension history, the pattern of initial manifestation, angiographic shape of VAD, angiographic location of VAD, treatment modality.

FINDINGS

There was no statistically significant difference between the functional outcome with age, gender, trauma history and past medical history of hypertension. Of 35 patients, 22 presented with SAH, 11 with ischemic symptoms and 2 were incidentally detected. The patients without SAH had a better functional outcome than those with SAH (p = 0.029). There was statistical significance between Hunt-Hess (H-H) grade and clinical outcome (p = 0.032). The shape and location of VAD was not significantly related to the functional outcome (p = 0.294, 0.840). But all the cases of rebleeding and mortality (except one case with initially poor H-H grade) developed exclusively in patients with aneurysms. There was no statistically significant correlation between the treatment modality and the outcome (p = 0.691).

CONCLUSION

The VAD patients with SAH would be recommended to be managed by either surgical or endovascular treatment, but those without SAH, could be managed conservatively with antiplatelet therapy and/or anticoagulation.

Clinically occult chronic dissecting aneurysm of the superior cerebellar artery in a child

An isolated chronic dissecting aneurysm of the left superior cerebellar artery was discovered incidentally in a 12-year-old girl. There was no history of any previous trauma or witnessed abnormal neurological incident at any stage during her life. She was and has since remained asymptomatic and the aneurysm has remained radiologically stable for over 3 years. A conservative approach to the management of such incidental asymptomatic lesions is thus suggested.

Late morphological progression of a dissecting basilar artery aneurysm after staged bilateral vertebral artery occlusion: case report

BACKGROUND

The authors present a patient who experienced late (5-year follow-up) morphological progression of a dissecting aneurysm of the distal basilar artery after treatment with a combined microsurgical and neuroendovascular Hunterian strategy. In addition to postulating about the possible reasons underlying the evolution of this lesion, the role of stenting is discussed.

CASE DESCRIPTION

The patient was 37 years old when she suffered a subarachnoid hemorrhage from spontaneous basilar artery dissection. At the time of the hemorrhage, minimal aneurysmal enlargement was noted angiographically, and she was therefore treated nonoperatively. On reimaging 5 months later, massive enlargement of the aneurysm was noted. The patient was treated with staged bilateral vertebral artery sacrifice using a combination of microsurgical and neuroendovascular techniques. The dominant vertebral artery was clip-ligated distal to the posteroinferior cerebellar artery, whereas the contralateral vertebral artery was coil-occluded cervically 1 week later.

CONCLUSIONS

Despite the patient remaining asymptomatic, follow-up angiography 5 years after the initial hemorrhage revealed further enlargement of the aneurysm as well as a newly discovered inferiorly projecting daughter sac measuring 5 mm in diameter. Clearly, certain aneurysms exist for which indirect approaches involving hemodynamic attenuation fail to prevent progression. With greater refinements in stent technology, such lesions may be more effectively treated.

Two cases of dissecting aneurysm of the distal posterior inferior cerebellar artery: possible involvement of segmental mediolytic arteriopathy in the pathogenesis

BACKGROUND

Dissecting aneurysm of the posterior inferior cerebellar artery (PICA) uninvolved with the vertebral artery is rare. The exact pathohistological diagnosis might result in 'unknown' because the underlying pathoanatomical features are, for a variety of reasons, not always identified.

CASE DESCRIPTION

We report herein two cases of dissecting aneurysm harbored in different segments of the distal posterior inferior cerebellar artery. In our cases, after trapping the PICA at both just proximal and distal to the aneurysm, the abnormal portion was successfully resected with/without an end-to-end anastomosis. The first patient made a good recovery, while the other died 2 days after the surgery. Although its pathogenetic etiology was unidentified in the second case, the formation of dissecting aneurysm had resulted from a segmental mediolytic arteriopathy in the first case.

CONCLUSION

This is the first report of a segmental mediolytic arteriopathy possibly being identified as causing an isolated dissecting aneurysm at this site.

Ruptured traumatic vertebral artery pseudoaneurysm in a child treated with trapping and posterior inferior cerebellar artery reimplantation

The authors present the case report of a pediatric patient with a ruptured traumatic pseudoaneurysm of the intracranial vertebral artery (VA) from which the posterior inferior cerebellar artery (PICA) emerged. After considering multiple therapeutic options, the patient was treated surgically by trapping of the aneurysm segment and direct reimplantation of the PICA distal to the rupture site. In addition to presenting this unique case, the authors discuss the treatment of VA pseudoaneurysms and the various techniques for PICA revascularization. A review of the literature on PICA reimplantation is provided as an adjunct in the treatment of complex VA aneurysms.

Successful treatment of a ruptured dissecting basilar artery aneurysm

✓ Dissecting basilar artery (BA) aneurysms in patients presenting with subarachnoid hemorrhage are life threatening, especially in those who experience subsequent bleeding or progressive dissection, and immediate surgical or endovascular intervention may be necessary. The authors report on a 52-year-old woman whose dissecting BA aneurysm was treated successfully with proximal occlusion and flow reversal. Clipping of the proximal BA above the level of the anterior inferior cerebellar arteries facilitated retrograde flow from a radial artery graft placed between the left vertebral artery and the left posterior cerebral artery, thereby providing continuous perfusion of the BA and its branches. Postoperative angiograms obtained 1 year later revealed good retrograde flow through the BA and dilation of the radial arterial graft. There were no episodes of recurrent hemorrhage.

Ischemic Basilar Artery Dissecting Aneurysm Treated by Stenting Only-Case Report-

A 45-year-old man presented with enlargement of basilar artery dissecting aneurysm 10 months after suffering brain stem infarction. Combined stenting and placement of Guglielmi detachable coils (GDCs) was planned to obliterate the aneurysm sac. Stent deployment was performed but the procedure was halted to avoid overdosing with contrast material. Cerebral angiography 10 days later showed thrombosis of the aneurysm sac and normalization of the blood flow in the basilar artery. The patient has been followed up for 2 years and showed good clinical and angiographic outcome. Stenting results in obliteration of the aneurysm sac, so a two-stage procedure is recommended.

Non-traumatic recurrent dissection and its spontaneous repair in the circle of Willis: report of two autopsy cases

Post-mortem examinations of the circle of Willis in two cases of subarachnoid hemorrhage disclosed a wide spectrum of vasculopathy ranging from a minimal tear between the intima and media, and between the media and adventitia, to complete transmural disruption leading to the formation of pseudoaneurysms. The presence of coexistence of the focal lesions with complete replacement of the entire arterial wall with thick fibrous connective tissues and the vasculopathy was suggestive of the spontaneous repair of recurrent non-traumatic dissection of intracranial arteries. The patients were 58-year-old and 43-year-old females. There was no history of injury to the head or neck in either case. They were hypertensive, but the degree of atherosclerotic changes in the circle of Willis was compatible with age. There was no histological evidence of vasculitis. The role of hypertension and medial mucoid degeneration in the genesis of non-traumatic dissection of intracranial arteries was discussed.

Isolated dissections and dissecting aneurysms of the posterior inferior cerebellar artery: topic and literature review

Isolated dissections of the posterior inferior cerebellar artery (PICA) are rare. Thus, no large series of cases have been reported in the literature. Due to limited knowledge regarding the natural history of these lesions and the lack of high-quality evidence supporting various treatment options, management is controversial and practice parameters are ill defined. In order to offer a comprehensive reference for the diagnosis and management of isolated PICA dissections, the authors reviewed the National Library of Medicine from 1966 to October 2001. Twenty-seven patients averaging 43.6 years of age and including 14 males and 13 females were reported. Subarachnoid hemorrhage occurred in 20 patients, and two died. Dissections were located in the proximal PICA in 22 patients and were three times more common on the left side (left:right=3:1). Six patients were managed conservatively, and four with endovascular techniques. Seventeen had open surgery: five underwent resection, two went through trapping, and two had proximal clipping. Wrapping with muscle was performed in two patients, encasement with Sundt clips in two, and four had occipital artery (OA)-PICA bypass surgery. A meticulous analysis of reported cases with regard to clinical and pathological features, management strategies, and outcomes is presented.

Arterial reconstruction by direct surgical clipping of a basilar artery dissecting aneurysm after failed vertebral artery occlusion: technical case report and literature review

OBJECTIVE AND IMPORTANCE

Dissecting aneurysms of the basilar artery are rare lesions with significant morbidity and mortality. Their management is controversial and often difficult. Although the rebleeding rate is high, clip reconstruction carries prohibitive risk because of the damage to the parent vessel induced by the dissection and the lack of tissue to gather. An enlarging pseudoaneurysm in the chronic phase, however, may have sufficient tissue for clip reconstruction. We present a case in which this strategy was used successfully.

CLINICAL PRESENTATION

A 45-year-old woman presented 3 months after an initial presentation with a subarachnoid hemorrhage from a dissecting aneurysm of the basilar trunk at an outside institution. The aneurysm had grown compared with previous angiograms.

INTERVENTION

The dominant vertebral artery was sacrificed. Despite this, the aneurysm continued to enlarge. Given the progressive enlargement of the aneurysm, the decision was made to proceed with arterial reconstruction by direct surgical clipping of the saccular component of the dissecting aneurysm. The patient made an excellent recovery with a durable result.

CONCLUSION

Although clipping an intracranial pseudoaneurysm in the acute phase may carry a prohibitive risk, clipping such an aneurysm in the chronic phase may occasionally be warranted. To our knowledge, this is the first case reported in the literature in which direct surgical clipping was used as the primary mode of treatment for a basilar artery dissecting aneurysm that enlarged despite occlusion of the dominant vertebral artery. We review the literature on this rare pathological entity and discuss our management strategy.

Dissecting giant vertebro-basilar aneurysms

OBJECT

Vertebro-basilar dissecting aneurysms (VDAs) are very rare in children. Strokes or subarachnoid hemorrhage are characteristic clinical manifestations, but often only non-specific symptoms are found. Radiological diagnosis may be difficult to obtain and therapy hard to perform. We report on a child who presented with an intracranial mass effect due to a giant VDA.

METHODS

The patient was a 8-year-old girl with right hemiparesis, ataxia, dysphagia and dysphonia and worsening of her neurological deficits. Neuroimaging discovered a giant dissecting aneurysm arising from the left vertebral artery and involving the vertebro-basilar junction. Endovascular treatment by coil embolization was performed. The post-operative course initially showed a remarkable improvement in her clinical condition. Afterwards, she developed cerebral hemorrhage and died.

CONCLUSION

VDAs may have an unusual presentation and their therapy still remains a challenge. Endovascular embolization is a valid option but, as it is surgery, it may cause the death of the patient.

Dissecting aneurysms of the middle cerebral artery: neuroradiological and clinical features

There are few reported cases of nontraumatic dissecting aneurysms of the middle cerebral artery (MCA), and their neuroradiological and clinical features have not been analysed. We looked at these aspects in a collaborative study. We reviewed 13 patients diagnosed as having a dissecting aneurysm of the MCA based on clinical signs and neuroradiological findings in 46 stroke centres between 1995 and 1999. There were four patients who presented with cerebral ischaemia, and nine who presented with bleeding. Of the former group, three were aged less than 15 years. Cerebral angiography showed extensive stenosis and a double lumen of the M1 portion in all four patients. High signal on T1-weighted images around the arterial flow void, due to intramural haematoma, was often seen in the second week. MR angiography showed findings corresponding those of intra-arterial angiography in all four cases. We saw an infarct on CT or MRI in territory of the perforating branches of the M1 segment in all four patients. In the patients presenting with bleeding, pure subarachnoid haemorrhage or a sylvian fissure haematoma was seen on initial CT, and the predominant angiographic finding was dilatation with stenosis, but the site of the lesions was not uniform. A double lumen or intimal flap was seen in about half the cases. Rebleeding occurred within 14 days of the onset in five of the nine patients, with a poor prognosis.