Neurosurgery Service, Alicante University General Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL - FISABIO Foundation), Alicante, Spain.
Frequently it is a wide necked aneurysm with an irregular shape, incorporate parent vessels, and are associated with significant variations in vascular anatomy.
The most common site of rupture of very small intracranial aneurysms was the anterior communicating artery (ACoA). Rupture of small and very small aneurysms is unpredictable, and treatment may be considered in selected high-risk patients according to factors such as young age, ACoA location, and hypertension 4).
A1 segment hypoplasia of the anterior cerebral artery is frequently observed in patients with anterior communicating artery aneurysms. The effect of this anatomical variant on ACoA aneurysm morphology is not well understood 5).
In clinic, it’s very common to find out the unequal development of section A1 of anteromedial brain artery. The resulting hemodynamic changes are considered to be one of the main reasons for the formation of anterior communicating artery aneurysms 6).
An asymmetry of the A1 segment of the anterior cerebral artery (A1SA) was identified on digital subtraction angiography studies from 127 patients (21.4%) and was strongly associated with ACoAA (p < 0.0001, OR 13.7). An A1SA independently correlated with the occurrence of ACA infarction in patients with ACoAA (p = 0.047) and in those without an ACoAA (p = 0.015). Among patients undergoing ACoAA coiling, A1SA was independently associated with the severity of ACA infarction (p = 0.023) and unfavorable functional outcome (p = 0.045, OR = 2.4).
An A1SA is a common anatomical variation in SAH patients and is strongly associated with ACoAA. Moreover, the presence of A1SA independently increases the likelihood of ACA infarction. In SAH patients undergoing ACoAA coiling, A1SA carries the risk for severe ACA infarction and thus an unfavorable outcome. Clinical trial registration no.: DRKS00005486 (http://www.drks.de/) 7).
Vascular imaging was evaluated with 3D Slicer© to generate models of the aneurysms and surrounding vasculature. Morphological parameters were examined using univariate and multivariate analysis and included aneurysm volume, aspect ratio, size ratio, distance to bifurcation, aneurysm angle, vessel angle, flow angle, and parent-daughter angle. Multivariate logistic regression revealed that size ratio, flow angle, and parent-daughter angle were associated with aneurysm rupture after adjustment for age, sex, smoking history, and other clinical risk factors. Simple morphological parameters such as size ratio, flow angle, and parent-daughter angle may thus aid in the evaluation of rupture risk of anterior communicating artery aneurysms 8).
Weisberg reviewed the CT findings in 40 patients with ruptured aneurysms of the anterior cerebral or anterior communicating arteries. Within 3 days of the ictus, the common patterns included blood in the pericallosal cistern and interhemispheric fissure, blood in the caval-septal region, unilateral or bilateral frontal hematoma, and diffuse symmetric intraventricular and basal cisternal blood 9).
For CT classification see the Modified Fisher scale.
Cohen et al., describe a technique for T-configured stent-assisted coiling in the management of ruptured wide-necked AcomA aneurysms by means of two simultaneous microsystems that allowed placement of two nitinol self-expandable Leo+ Baby stents (Balt Therapeutics, Montmorency, France) followed by coiling. Technical details and comparison to other dual stent configurations were presented and briefly discussed 10).
A 69-year-old male without a past history of mental disorders and neurological symptoms presented with a 2-month history of anxiety, sadness, lack of pleasure in usual activities, fatigue, difficulties falling asleep and waking up early in the morning, reduced appetite, and weight loss. The patient was diagnosed with major depressive disorder and antidepressant treatment was initiated. Subsequent non-contrast computed tomography (CT) of the head demonstrated hypointense oval-shaped lesion within the projection of the anterior communicating artery. CT angiography confirmed the diagnosis of a 0.8 × 0.6 cm saccular aneurysm originating from the anterior communicating artery and anterior cerebral artery. The patient underwent microsurgical clipping of the aneurysm. On psychiatric assessment 1 month after the surgery, there were no signs of depressive disorder and antidepressive treatment was discontinued. On follow-up visit 1 year after the surgery, the patient did not have any mood symptoms.
The case indicates that organic brain lesions, including intracranial aneurysms, should be suspected in elderly patients presenting with their first episode of mental disorder 11).
Seung et al., present an unusual case of bitemporal hemianopsia caused by a large intracranial aneurysm of the ACoA. A 41-year-old woman was admitted to our neurosurgical department with a sudden-onset bursting headache and visual impairment. On admission, her vision was decreased to finger counting at 30 cm in the left eye and 50 cm in the right eye, and a severe bitemporal hemianopsia was demonstrated on visual field testing. A brain computed tomography scan revealed a subarachnoid hemorrhage at the basal cistern, and conventional cerebral catheter angiography of the left internal carotid artery demonstrated an 18×8 mm dumbbell-shaped aneurysm at the ACoA. Microscopic aneurysmal clipping was performed. An ACoA aneurysm can produce visual field defects by compressing the optic chiasm or nerves. We emphasize that it is important to diagnose an aneurysm through cerebrovascular study to prevent confusing it with pituitary apoplexy 12).
A 55-year-old man presented with a 3-year history of visual impairment associated with personality changes. His sister had died after an intracerebral aneurysmal rupture. An examination revealed poor visual acuity in the right eye with a field defect, as well as impaired neurocognition. Computed tomographic (CT) angiography (Panel A) and magnetic resonance imaging of the brain revealed a partially thrombosed, calcified, 7-cm aneurysm of the anterior communicating artery, with surrounding edema (Panel B). Thrombectomy and aneurysmal repair were performed to reduce the risk of aneurysmal rupture and to alleviate the mass effect. The patient recovered from surgery and had improvement in his neurocognitive deficits and vision, and he was able to return to work. His condition remained stable 2 years later, and delayed CT showed collapse of the aneurysmal sac (Panel C). Giant aneurysms (>2.5 cm) represent a small proportion of brain aneurysms but are associated with a high rupture rate when left untreated. Approximately 20% of patients with a brain aneurysm have a first-degree relative with a brain aneurysm 13).
A study reports the case of a 42-year-old man who suffered a ruptured aneurysm of the anterior communicating artery. His memory capabilities were assessed after a considerable recovery period during which many of his memory deficits ameliorated. His scan revealed a left frontal lesion and many of his deficits were characteristic of frontal impairment. He was impaired on temporal discrimination, and he showed marked source forgetting. He also performed badly on the Brown-Peterson task, and we suggest that this is another task that may be characteristic of frontal impairment. In contrast, the patient showed normal or near normal performance on some memory tasks but not on others. It is concluded that the patient's frontal signs are similar to those found in Korsakoff's Syndrome, but that his memory impairment is qualitatively different from that encountered in patients with the amnesic syndrome 14).