[Radiologic anatomy of the labyrinth artery]

Prior research has shown that the labyrinth artery, also known as the artery of the labyrinth (AL), plays a role in supplying blood to the inner ear. However, no prior work had resolved the detailed anatomical variations of this vessel in a large patient cohort. It was already known that the AL originates from the posterior circulation, but the specific branching patterns and morphological differences remained unclear. That uncertainty drove the need for a systematic angiographic analysis to map the AL's origin and course. The posterior inferior cerebellar artery and basilar artery were suspected as potential sources, but the frequency of each had not been quantified. No prior work had resolved the symmetry of the AL between the left and right sides. The anatomical variability of the AL could impact diagnostic imaging and surgical planning in the posterior cranial region. This gap motivated a study using digital subtraction angiography to document the AL's morphology in a clinical setting.

The aim of this study was to describe the radiologic anatomy of the artery of the labyrinth using angiographic data from a sample of 96 patients. The researchers wanted to clarify the origin, length, and curvature of the AL in different anatomical contexts. They focused on the posterior circulation, particularly the inferior anterior cerebellar artery and the basilar artery, as potential sources. The study sought to quantify the proportion of patients in which the AL originated from each of these vessels. The researchers also intended to assess the AL's path as it approached the internal acoustic meatus. They aimed to determine whether the AL formed loops or semiloops in this region. The study further aimed to evaluate the symmetry of the AL between the left and right sides. This information could help improve the accuracy of neuroimaging and surgical interventions involving the posterior cranial fossa.

The study used digital subtraction angiography to visualize the artery of the labyrinth in 96 inpatients. The researchers analyzed the origin of the AL from the inferior anterior cerebellar artery or the basilar artery. They measured the length of the AL in both anatomical variants. The curvature of the AL was assessed based on its origin and path. The researchers documented the AL's position relative to the upper edge of the pyramid. They evaluated the formation of loops or semiloops within or at the internal acoustic meatus. The study compared the left and right ALs for symmetry in morphology and length. The data were compiled to describe the frequency and characteristics of each anatomical variant.

The AL originated from the distal part of the inferior anterior cerebellar artery in 66.3% of cases. In these instances, the AL had a straight morphology. When the AL originated from the proximal part of the basilar artery, it was shorter, measuring 0.8 ± 0.3 cm. These ALs were also curved in shape. The AL consistently ran along the upper edge of the pyramid before entering the internal acoustic meatus. Within or at the meatus, the AL formed a loop or semiloop in all observed cases. The AL's length from the inferior anterior cerebellar artery was 2.5 ± 0.8 cm. Symmetry between the left and right ALs was observed in 61.8% of patients.

The study suggests that the AL's origin and morphology vary significantly among individuals. The AL most commonly originates from the distal part of the inferior anterior cerebellar artery. When it arises from the basilar artery, it is shorter and curved. The AL's path along the upper edge of the pyramid is consistent across anatomical variants. The formation of loops or semiloops within the internal acoustic meatus is a characteristic feature. Symmetry between the left and right ALs occurs in a minority of cases. These findings may help improve the interpretation of cerebrovascular imaging. The anatomical variability of the AL could influence surgical approaches in the posterior cranial region. The results propose that radiologists should be aware of these variations to avoid misinterpretation.