Morphological Analysis of Cerebral Artery Fenestrations and Their Correlation with Intracranial Aneurysms

Fenestration of the anterior and posterior cerebral arteries in coexistence with a contralateral posterior cerebral artery of fetal origin

PURPOSE

The present case report aims to describe the rare coexistence of three variants of the cerebral arterial system diagnosed by computed tomography angiography (CTA).

METHODS

A retrospective study on head and neck CTAs was performed on a Greek adult population from the Department of Radiology, University Hospital of Larissa. An interesting case of an 80-year-old male was further investigated.

RESULTS

The cerebral arterial circle presented with a combination of three variations. The left anterior cerebral artery (ACA) was fenestrated 1.4 mm proximally to the anterior communicating artery formation. The left posterior cerebral artery (PCA) was also fenestrated, 5.5 mm distally to its origin from the basilar artery. Lastly, the right PCA originated from the ICA supraclinoid segment.

CONCLUSIONS

This case report highlights an unusual coexistence of A1 and P1 segments fenestration with a fetal PCA, resulting in a unique cerebral circle. A1 segment fenestration has been previously reported as rare, while the PCA fenestration as extremely rare variant. Awareness of these rare variations could aid interventionists in their preoperative assessments.

Anatomical Variations and Anomalies of the Middle Cerebral Artery

OBJECTIVE

Intracranial arteries have a high rate of variation, but a clear schematic overview is lacking. In this pictorial review we classify and depict all the variations and anomalies within the middle cerebral artery (MCA).

METHODS

PubMed was searched with the MeSH-term "Middle Cerebral Artery." Articles were selected based on their description of variants within the MCA. Cross-referencing was used to broaden the range of articles. The anatomical variants were then schematically drawn using the anteroposterior and lateral view during angiography of the internal carotid artery.

RESULTS

A total of 29 unique medical illustrations were made, depicting variation in number of vessels; variation in vessel origin; and variation in morphology.

CONCLUSIONS

The MCA provides vital blood supply to the frontal, parietal, temporal, and central brain structures. An overview of these variations is important to diagnose and treat patients with MCA-related pathology correctly and safely. They can aid in distinguishing pathology from normal anatomical variance; aid neurosurgeons during aneurysmal clipping or arteriovenous malformation resections; and aid interventional radiologists during thrombectomy or coiling. This article provides a summary regarding current knowledge of anatomical variations within the MCA, their prevalence and clinical relevance. A total of 29 unique illustrations were made, depicting currently known variants. We encourage all who diagnose, treat, and study the MCA to use this overview for a uniform and better understanding of its anatomy.

Fenestration of the superior cerebellar artery diagnosed by magnetic resonance angiography

We herein report a case of fenestration of the superior cerebellar artery (SCA), which was incidentally diagnosed by magnetic resonance (MR) angiography. A 65-year-old woman was referred to our hospital for unruptured cerebral aneurysms. MR angiography revealed 2 unruptured aneurysms. It also showed fenestration of the left SCA near its origin from the basilar artery, as well as several other vascular variations: a left common carotid artery arising from the brachiocephalic trunk, and a right vertebral artery terminating to the right posterior inferior cerebellar artery. Yearly observation was chosen as a treatment strategy due to the small size of the cerebral aneurysms. According to previous reports, SCA fenestration is an extremely rare variation. This is the second case of SCA fenestration diagnosed by MR angiography in the relevant English-language literature.

Funnel Shaped Anterior Communicating Artery Fenestration Mistaken for an Aneurysm: A Cautionary Tale

This report portrays a case of a funnel shaped anterior communicating artery (ACoA) fenestration which was mistaken as a small A1 aneurysm in a subarachnoid hemorrhage case. Although tridimensional rotational digital subtraction angiography improves aneurysm diagnosis specially at the ACoA complex, current spatial resolution might leave behind a considerable percentage of ACoA fenestrations. This may lead to diagnostic errors and unnecessary treatments risking iatrogenic complications. Luckily for our patient, a concomitant aneurysm warranted clipping and subsequent surgical exploration of the ACoA complex revealed the pitfall, thus preventing further action. Interestingly, another group of authors who reported similar misdiagnosis with ACoA aneurysms were able to prevent a third error, thanks to the experience acquired with 2 prior cases. Therefore, this clinical image aims to raise wider awareness of the need for very cautious consideration of imaging depicting small and/or atypical aneurysms in the ACoA complex.

Stenting-assisted embolization of a saccular aneurysm of the azygos anterior cerebral artery associated with fenestration at its beginning

Aneurysms of the azygos anterior cerebral artery (AACA) associated with fenestration are exceptional. We reported such a case. A 61-year-old woman presented with subarachnoid hemorrhage. Computed tomography angiography and digital subtraction angiography showed an aneurysm at the distal end of the AACA with a fenestration at its beginning. Stenting-assisted coiling of the aneurysm was performed. The postoperative recovery was uneventful. Follow-up DSA showed complete coiling of the aneurysm. By this case report and review of the literature, we found that the coexistence of the aneurysm and fenestration on the AACA was exceptional. Endovascular treatment of saccular AACA aneurysms is an appealing option.

Retrospective analysis of image characteristics of 76 cases of cerebral vascular fenestrations

Objectives

This study aims to summarize the clinical and imaging features of cerebral vascular fenestration and to explore the association between cerebral vascular fenestration and cerebral infarction and aneurysm.

Materials and methods

The computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) imaging data of 76 cases of cerebral vascular fenestration from January 2021 and December 2021 in the Yantai Yuhuangding Hospital Affiliated to Qingdao University were analyzed. The general information was described. The location, morphology, and size of cerebral vascular fenestration were described. The association between cerebral vascular fenestration and infarction and aneurysm was analyzed.

Results

Among 76 patients, a total of 80 fenestrations were detected (two patients had three fenestrations), and basilar artery fenestration was the most common (28/80). The fenestration <5 mm was 43/80, 5-10 mm was 12/80, and ≥10 mm was 25/80. Moreover, 19 patients had other vascular diseases: 10 with aneurysms, 5 with moyamoya diseases, and 4 with cerebral artery dissections. Except for one aneurysm at the site of the fenestration, other aneurysms were separate from the fenestrations. In addition, 37 patients had cerebral infarctions, of which 16 had cerebral infarctions in the blood supply area of the arterial fenestration. Among these 16 patients, there was more cerebral infarction in posterior circulation than in anterior circulation. However, no statistically significant differences were detected in the risk factors between the fenestration-relevant cerebral infarctions group and the non-fenestration-relevant cerebral infarctions group.

Conclusion

In our study, cerebral vascular fenestration occurred most frequently in the basilar artery and may be combined with other vascular diseases. Fenestration in posterior circulation may be related to cerebrovascular diseases. Nonetheless, no clear clinical relevance was observed between fenestration and cerebral infarction. Also, we did not find a definite association between fenestration and aneurysm. For fenestration patients with cerebral infarctions, long-term antiplatelet and statin therapy may be safe and effective.

The Incidence, Localization and Clinical Relevance of Arterial Fenestrations and Their Association to Brain Aneurysms: A Case-Control Study Based on the STROBE Guidelines

Background: Fenestrations are rare, but well-known, vascular variations of the cerebral arteries. They are mostly incidental, asymptomatic angiographic findings and might precipitate vascular lesions such as AVM, aneurysmal dilatation, or even ischemic symptoms. However, association between arterial fenestration and brain aneurysms has not been clearly established. Objective: To evaluate whether incidence of arterial fenestrations are associated with brain aneurysm development and investigate the prevalence and most-common localizations of arterial fenestrations of the human brain. Design: Case−control study. Setting: All patients examined by CT angiography in University Hospital No. 4 in Lublin from 2009 to 2019. Patients: Each patient showing at least one cerebral aneurysm was included in the case group and each patient without cerebral aneurysm on CT angiography was included in the control group. Measurements: CT angiography examinations were conducted using the standard protocol used in the 1st Department of Radiology, Medical University of Lublin, Poland. The database and statistical research were conducted by use of the Statistica software (ver. 13.3, Tibco Software Inc., Palo Alto, CA, USA). Results: A total of 6545 CTA examinations were included in the study. Most of the aneurysms were located on the MCA: 629 (38.59%), ICA: 466 (28.59%) and AComA: 192 (11.78%). Cerebral arterial fenestration showed a non-statistically significant elevated risk for brain aneurysms in the entire study population (OR: 1.157; 95% CI: 0.826−1.621; p = 0.39). Among 6545 cranial CTA examinations, cerebral vessel fenestration was found in 49 of them, which constituted 0.75%. The most common vascular fenestrations were those located in the ACA (30.61%), BA (30.61%) and AComA (22.45%), while other fenestrations occurred infrequently. There were no significant differences in the age of patients in the individuals with vascular fenestration (p > 0.05). VA fenestration was slightly more common in men (16.67%) than in women (5.41%). However, these differences were not statistically significant (p = 0.216). Limitations: Our study has several limitations, including selection bias regarding examined population. Second, we assume that the total number of fenestrations detected in our study was underestimated due to the limitations of the CT method in comparison to other radiologic modalities. Conclusions: Cerebral arterial fenestrations are rare vascular malformations. The ACA is the most common localization of fenestrations, followed by BA and AComA. Fenestrations of cerebral arteries insignificantly increase the risk of cerebral aneurysm formation. Further prospective studies are necessary to make this association more precise.