Anterior communicating artery aneurysm classification

J.Sales-Llopis

Neurosurgery Service,General University Hospital Alicante, Spain.

• Angiographic Occlusion After Flow Diversion of Ruptured and Unruptured Intracranial Aneurysms Using the Flow Redirection Endoluminal Device-X: A Multicenter Analysis
• High-resolution CT angiography for follow-up evaluation of intracranial aneurysms treated with the Woven EndoBridge device: comparison with digital subtraction angiography
• Association between body mass index and intracranial procedural complications in patients undergoing endovascular treatment for unruptured aneurysms
• DWI-based deep learning radiomics nomogram for predicting the impaired quality of life in patients with unruptured intracranial aneurysm developing new iatrogenic cerebral infarcts following stent placement: a multicenter cohort study
• Evaluation of techniques for automated classification and artery quantification of the circle of Willis on TOF-MRA images: The CROWN challenge
• Assessing Occlusion and Recovery in Large and Giant Intracranial Aneurysms: A Comparative Retrospective Study of Flow Diversion Alone Versus Combined With Coiling and the Role of Packing Density
• Middle cerebral artery aneurysms in older women with autosomal dominant polycystic kidney disease
• Interdependence of First-coil and Global volume embolization ratios (VERs) calculated by Sim&Size in predicting aneurysm occlusion outcomes

(Anteroinferior)-Projecting (Unruptured) (Saccular) (Wide necked) (Giant) anterior communicating artery aneurysm

Anterior communicating artery aneurysm orientation

see Intracranial aneurysm classification

Giant anterior communicating artery aneurysms are rare.

Ruptured anterior communicating artery aneurysm.

Unruptured anterior communicating artery aneurysm.

see Wide necked anterior communicating artery aneurysm.

Anterior communicating artery aneurysms frequently present wide aneurysm necks and incorporate parent vessels. They are associated with significant variations in vascular anatomy, especially hypoplasia or aplasia of one of the proximal anterior cerebral artery.

Morphological Scoring System of Choi

Unfavourable for endovascular treatment (score ≥2).

see Aspect ratio.

see Dome Neck ratio.

see Neck Dimension.

According to 2D-DSA, the points of aneurysm are divided into 5 types ^{1) 2)}.

Chen et al., classified as Type I, II (IIa, IIb), III and IV, based on the various projections and size of aneurysm. The principle for the choice of operative side was designed based on the type of aneurysm and the A2 fork orientation (the interrelations between the plane of bilateral A2, AComA, and mid-saggital plane) ³⁾.

Small aneurysms located at the anterior communicating artery carry significant procedural challenges due to a complex anatomy.

A retrospective analysis was performed of 155 patients with ruptured AComA-located aneurysms. The percentage of difference between both A1 arteries was measured on computed tomography angiography images and neck locations were determined. Accordingly, AComA-located aneurysms were classified into 2 groups. In both groups, A1 and A2 arteries and neck size diameters were measured and their relation with aneurysmal depth was studied. The aspect ratio was calculated.

Eleven patients in which the aneurysm neck originates from the AComA proper with almost equal A1s were classified as the true AComA aneurysm group whereas 144 patients in whom the aneurysm neck originates at the dominant A1 bifurcation into the AComA and A2 with the average difference between both A1s of about 84.44% were classified as the dominant A1-bifurcation group. There is significant correlation between aneurysmal depth and neck diameter in both groups (P ≤ 0.05, P < 0.001). The aspect ratio was calculated as equal to 1.166.

The dominant A1 bifurcation type is the most common type of AComA-located aneurysm. The present classification provides clinical value in understanding how AComA aneurysms grow and behave. It helps to understand the geometry of multilobulated aneurysms such as ruptured blebs locations during treatment procedures respecting the direction of the dominant A1 axis in group II. Multiple anatomic variations of this complex AComA area can clarify future subtypes of these 2 groups. Thus, further investigation of more patients is needed ⁴⁾.

Of 2332 intracranial aneurysm patients, 1.76% (n = 41) had a total of 42 A1 aneurysms. Twenty-six of these (62%) were proximal A1 segment aneurysms, 9 (21%) were distal A1 segment aneurysms, and 7 (17%) were fusiform A1 aneurysms. A1 aneurysms can be classified into 3 main types. Types IA and IB originate from the posterior wall of the proximal A1 segment. Type IA projects posterior-inferiorly, whereas type IB projects posterior-superiorly. Type IIA originates from the distal trunk of the A1 artery. Type IIB originates from an angle of an abnormal cortical branch or a ring of an A1 arterial fenestration. Type III consists of fusiform or dissecting aneurysms located anywhere along the A1 segment. After studying the range of treatments and outcomes, when treating these complex morphologies, we recommend clipping type I and II A1 aneurysms and embolizing type III A1 aneurysms.

A1 artery aneurysms are a rare type of aneurysm with unique characteristics. The classification system proposed here accurately summarizes these characteristics to better guide treatment strategies ⁵⁾.

Ten aneurysms of the horizontal portion of the anterior cerebral artery (A1) were analyzed. These 10 aneurysms were classified into three types according to the mode of the origin of the neck of the aneurysm from the A1 segment: (a) an aneurysm originating from the junction of the A1 segment and the lenticulostriate artery, (b) one from the proximal end of the fenestration of the A1, and © one from the top of the A1 loop (elongation and kinking of the A1 segment). In these aneurysms, their size, the side of the A1 segment with an aneurysm, the multiplicity of aneurysms, the coexistence of hypertension, the grade of the patients, the laterality of the subarachnoid blood clots (as seen on computed tomography scans) and surgical outcome were analyzed ⁶⁾.

Anterior communicating artery aneurysm and pericallosal artery aneurysm.