Blood flow velocity in the arteries of the anterior cerebral artery complex in patients with an azygos anterior cerebral artery aneurysm: A transcranial color-coded sonography study

Anterior Interhemispheric Approach for the Surgical Treatment of Azygos Anterior Cerebral Artery Aneurysms: A Case Series

The azygos artery is an uncommon vascular variant of the anterior cerebral artery (ACA). This anomaly is associated in a high percentage with aneurysms. Management of azygos ACA aneurysms represents a surgical challenge. We present five patients who underwent microsurgical treatment for distal azygos ACA aneurysms with complex morphology. Four patients showed subarachnoid hemorrhage (SAH) and one complained of sentinel headache. Early preoperative digital subtraction angiography (DSA) or computerized tomography angiography (CTA) was performed. All patients were treated by surgical clipping via an anterior interhemispheric approach. During follow-up, all patients had a satisfactory outcome, with postoperative angiograms showing complete resolution of aneurysms.

Endovascular treatment of a ruptured blister-like aneurysm at an azygos anterior cerebral artery: A case report and review of the literature

Background

Endovascular treatment for a ruptured blister-like aneurysm (BLA) has recently become a hopeful approach. BLAs are usually located on the dorsal wall of the internal carotid artery, whereas one located on the azygos anterior cerebral artery (ACA) is so rare, it has never been reported. We report a case of a ruptured BLA arising at the distal bifurcation of an azygos ACA treated by stent-assisted coil embolization.

Case Description

A 73-year-old woman presented with a disturbance of consciousness. Computed tomography showed diffuse subarachnoid hemorrhage, which was observed to be particularly dense in the interhemispheric fissure. Three-dimensional rotation angiography showed a tiny and conical bulge on the distal bifurcation of the azygos trunk. Follow-up digital subtraction angiography performed on day 4 showed enlargement of the aneurysm, and a BLA arising at the azygos bifurcation was diagnosed. Stent-assisted coiling (SAC) was performed using a low-profile visualized intraluminal support (LVIS) Jr. stent, which was implanted from the left pericallosal artery to the azygos trunk. Follow-up angiography showed that the aneurysm thrombosed gradually and reached complete occlusion 90 days after onset.

Conclusion

SAC for a BLA at the distal bifurcation of an azygos ACA might be an effective treatment option leading to early complete occlusion, but thrombus formation as an intraoperative complication should be noted in the BLA at the bifurcation or the peripheral artery, as in the present case.

Transcranial Doppler ultrasonography (uses, limitations, and potentials): a review article

Background

The additional information that transcranial Doppler can provide as part of a multimodal imaging protocol in many clinical settings has not been evaluated.

Main body

Transcranial Doppler is a bedside procedure used to assess cerebral blood flow velocity via cerebral circulation and pulsatility index (PI). Many diseases can lead to cerebral vessels vasospasm as in subarachnoid hemorrhage and trauma. Cerebral vessels vasospasm represented by abnormal elevation of cerebral blood flow velocity. Intracranial pressure can be monitored by pulsatility index which reflects blood flow resistance in cerebral vessels. Transcranial Doppler ultrasonography is also the unique modality for detection of micro emboli in high-risk patients. Also, it can be used for evaluation of circulatory arrest with subsequent confirmation of brain death

Conclusion

Transcranial Doppler ultrasonography is the only diagnostic modality that provides a reliable assessment of cerebral blood flow patterns in real time. The physiological information obtained from TCD is complementary to the anatomical details obtained from other neuroimaging modalities. TCD is relatively cheap, can be performed bedside, and allows monitoring in acute emergency settings.

A De Novo Aneurysm of the Anterior Cerebral Azygos Artery Following a Middle Cerebral Arterial Aneurysm with Subarachnoid Hemorrhage

A de novo aneurysm of a cerebral artery, defined as a newly growing aneurysm after aneurysmal clipping, but not close to a previously clipped one, is relatively rare. Five studies have reported that the annual incidence of de novo aneurysm formation ranged from 0.3% to 1.8%. A 56-year-old man presented with headache. Magnetic resonance angiography (MRA) and computed tomography (CT) showed an aneurysm with arachnoid hemorrhage located at the left middle cerebral artery (MCA) associated with an azygos anterior cerebral artery (ACA). Eight years later, the patient complained of dizziness, and MRA demonstrated no visualization of the MCA on the left due to metal artifact, but a new lesion, an azygos ACA aneurysm, 9 mm in diameter, was seen. Clipping was performed using multiple clips through the interhemispheric space. Late follow-up examination with MRA or three-dimensional CT to detect de novo aneurysms should be considered in a patient with this vascular anomaly after subarachnoid hemorrhage.

Anatomical variants of anterior communicating artery complex. A study by Computerized Tomographic Angiography

Advances in imaging techniques have led to the identification of normal variations and abnormalities of cerebral arteries. Although the anterior communicating artery complex (ACAC) variations are usually asymptomatic, their description is essential in the radiologic report, since they can have clinical relevance. The aim of this study is to describe arterial anomalies of the ACAC and their prevalence. A retrospective observational descriptive analysis of ACAC variations in Computerized Tomographic Angiography (CTA) was performed. All CTA (426 studies) obtained in our center from 2015 to 2017 were included. Presence of aneurysm was recorded and its relationship with arterial variants was analyzed with a Chi-square test. The most common variants found in our study are linked to the A1 segment (42.3%) of the anterior cerebral artery (ACA): absence: 10.6%, hypoplasia: 31.2%, fenestration: 0.5%. A2 segment variants were present in 15.3% (absence: 0.2%; hypoplasia 8.5%; Azygos artery: 1.4%; triple ACA: 5.2%). Anterior Communicanting Artery was typical in 92.5%, absent in 4.7%, double/fenestrated in 0.9%, triple in 0.2%, X-shape in 1.2% and Y-shape in 0.2%. Aneurysms were present in 10.7%. Anterior circulation aneurysm involved the 50% of patients with aneurysm. Although the 60.9% of them showed artery variants, they did not reach statistical significance (p = 0.6). In conclusion, the Anterior Communicating Artery Complex presents variations in its anatomy. The most common anterior circulation vascular variants are the hypoplasia and the absence of the A1 segment. There does not appear to be a clear association between intracranial aneurysms and anatomical variations.

A case of delayed distal coil migration after coil embolization of an unruptured distal azygos anterior cerebral artery aneurysm: A case report and literature review

Intraprocedural coil migration during endovascular treatment for an aneurysm that might carry serious ischemic complications is well known. On the other hand, delayed coil migration after endovascular treatment for an aneurysm is very rare. A 77-year-old woman was incidentally diagnosed with unruptured aneurysm associated with distal azygos anterior cerebral artery (ACA). The aneurysm was located at the distal bifurcation of the azygos ACA and was wide necked (approximately 7 mm in diameter). Endovascular coil embolization was selected and the aneurysm was occluded successfully, but 29 days after endovascular therapy, follow-up computed tomography (CT) and magnetic resonance (MR) angiography revealed distal coil migration in the peripheral portion of the ACA. In addition, CT on day 57 after therapy revealed the migrated coil had moved more distally. Fortunately, in the course of these events, the patient remained asymptomatic. To the best of our knowledge, this represents the first case of delayed distal coil migration associated with relatively rare azygos ACA aneurysm, and also the first report confirming more distal coil movement over time. In the future, a large number of patients could develop this complication as more aneurysms are aggressively treated with endovascular treatment. Knowledge regarding the possibility of delayed coil migration is thus important.

Types of Azygos Distal Anterior Cerebral Artery Branching Patterns: Relevance in Aneurysmal Surgery

Azygos distal anterior cerebral artery (Az.DACA) is a rare anatomical variant. This variant has been found to be associated with aneurysms in a significant proportion of patients. We present two cases of Az.DACA aneurysms associated with this anatomical variant with different branching patterns and the corresponding technical difficulties in clipping such aneurysms. Aneurysms associated with Az.DACA present unique technical challenges in proportion to the number of branches arising near the neck and should be managed at high volume centres with the best of facilities.

Giant saccular distal azygos artery aneurysm: Report of a case and review of literature

An azygos anterior cerebral artery (ACA) is a rare variant of normal embryogenesis in which confluence of two A1 segments results in a single A2 segment with the absence of anterior communicating artery. The occurrence of an aneurysm at the bifurcation of azygos ACA is rare with few cases reported in the literature. We report a case of a 40-year-old lady who presented with subarachnoid hemorrhage following rupture of a giant, saccular distal azygos ACA aneurysm. Bifrontal craniotomy and clipping of an aneurysm was performed. The clinical significance of azygos ACA and surgical strategies in clipping these aneurysms are discussed with a review of literature.